Effect of hydraulic retention time on the performance of down-flow hanging sponge system treating grey wastewater.

PubMed

Tawfik, Ahmed; Wahab, Rifaat Abdel; Al-Asmer, Azza; Matary, Fatma

2011-08-01

Grey wastewater (GW) treatment via down-flow hanging sponge (DHS) system was the subject of the study. The reactor was operated at different hydraulic retention times (HRTs) of 11.7, 5.8 and 2.9 h, corresponding to organic loading rates (OLRs) of 1.9, 3.6 and 6.8 kgCOD/m3 day, respectively. The results obtained revealed that decreasing the HRT from 11.7 to 2.9 h negatively affected on the performance of the DHS system. COD(total), COD(soluble), COD(particulate) and detergent removal efficiency were reduced from 96 ± 2.4 to 90 ± 2.3%, from 83 ± 10 to 69 ± 8%, from 98 ± 2 to 94 ± 3% and from 96 ± 12 to 88 ± 6.9%, respectively. However, the removal efficiency of the distinguished COD fractions and detergent remained unaffected when decreasing the HRT from 11.7 to 5.8 h. The DHS system provided a removal efficiency of 95 ± 1% for COD(total), 79 ± 8% for COD(soluble), 98 ± 2 for COD(particulate) and 94.7% for detergent at an HRT of 5.8 h. Based on these results, it is recommended to operate such a system at an HRT of 5.8 h and OLR not exceeding 3.6 kgCOD/m3 day for producing an effluent quality complying for reuse in unrestricted irrigation purposes. The removal of TKj-N and nitrification efficiency in the DHS system was significantly affected by increasing the OLR from 1.9 to 3.6 kgCOD/m3 day and from 3.6 to 6.8 kgCOD/m3 day. At an OLR of 1.9 kgCOD/m3 day, the DHS system removed 80 ± 12% of TKj-N and 91 ± 22% of ammonia which is significantly higher than that at an OLR of 3.6 (58.5 ± 13%) and 6.8 kgCOD/m3 day (26.8 ± 16%). Similar results were recorded for the removal of total coliform (TC), viz., the efficiencies dropped for TC from 99.8 ± 0.2 to 99.4 ± 0.8% and from 99.4 ± 0.8 to 90.0 ± 7.6%, respectively. DHS profile results showed that the major part of COD was removed in the upper portion of the system while the nitrification process was taken place in the lower part of the DHS system at OLR of 1.9 kgCOD/m3 day and HRT of 11.7 h.

Multi-stage hybrid subsurface flow constructed wetlands for treating piggery and dairy wastewater in cold climate.

PubMed

Zhang, Xiaomeng; Inoue, Takashi; Kato, Kunihiko; Izumoto, Hayato; Harada, June; Wu, Da; Sakuragi, Hiroaki; Ietsugu, Hidehiro; Sugawara, Yasuhide

2017-01-01

This study followed three field-scale hybrid subsurface flow constructed wetland (CW) systems constructed in Hokkaido, northern Japan: piggery O (2009), dairy G (2011), and dairy S (2006). Treatment performance was monitored from the outset of operation for each CW. The ranges of overall purification efficiency for these systems were 70-86%, 40-85%, 71-90%, 91-96%, 94-98%, 84-97%, and 70-97% for total N (TN), NH 4 -N, total P, chemical oxygen demand (COD), biochemical oxygen demand, suspended solid, and total Coliform, respectively. The hybrid system's removal rates were highest when influent loads were high. COD removal rates were 46.4 ± 49.2, 94.1 ± 36.6, and 25.1 ± 15.5 g COD m -2 d -1 in piggery O, dairy G, and dairy S, with average influent loads of 50.5 ± 51.5, 98.9 ± 37.1, and 26.9 ± 16.0 g COD m -2 d -1 , respectively. The systems had overall COD removal efficiencies of around 90%. TN removal efficiencies were 62 ± 19%, 82 ± 9%, and 82 ± 15% in piggery O, dairy G, and dairy S, respectively. NH 4 -N removal efficiency was adversely affected by the COD/TN ratio. Results from this study prove that these treatment systems have sustained and positive pollutant removal efficiencies, which were achieved even under extremely cold climate conditions and many years after initial construction.

Treatment of hazardous landfill leachate using Fenton process followed by a combined (UASB/DHS) system.

PubMed

Ismail, Sherif; Tawfik, Ahmed

2016-01-01

Fenton process for pre-treatment of hazardous landfill leachate (HLL) was investigated. Total, particulate and soluble chemical oxygen demand (CODt, CODp and CODs) removal efficiency amounted to 67%, 47% and 64%, respectively, at pH value of 3.5, molar ratio (H2O2/Fe(2+)) of 5, H2O2 dosage of 25 ml/L and contact time of 15 min. Various treatment scenarios were attempted and focused on studying the effect of pre-catalytic oxidation process on the performance of up-flow anaerobic sludge blanket (UASB), UASB/down-flow hanging sponge (DHS) and DHS system. The results obtained indicated that pre-catalytic oxidation process improved the CODt removal efficiency in the UASB reactor by a value of 51.4%. Overall removal efficiencies of CODt, CODs and CODp were 80 ± 6%, 80 ± 7% and 78 ± 16% for UASB/DHS treating pre-catalytic oxidation effluent, respectively. The removal efficiencies of CODt, CODs and CODp were, respectively, decreased to 54 ± 2%, 49 ± 2% and 71 ± 16% for UASB/DHS system without pre-treatment. However, the results for the combined process (UASB/DHS) system is almost similar to those obtained for UASB reactor treating pre-catalytic oxidation effluent. The DHS system achieved average removal efficiencies of 52 ± 4% for CODt, 51 ± 4% for CODs and 52 ± 15% for CODp. A higher COD fractions removal was obtained when HLL was pre-treated by Fenton reagent. The combined processes provided a removal efficiency of 85 ± 1% for CODt, 85 ± 1% for CODs and 83 ± 8% for CODp. The DHS system is not only effective for organics degradation but also for ammonia oxidation. Almost complete ammonia (NH4-N) removal (92 ± 3.6%) was occurred and the nitrate production amounted to 37 ± 6 mg/L in the treated effluent. This study strongly recommends applying Fenton process followed by DHS system for treatment of HLL.

Pathway governing nitrogen removal in artificially aerated constructed wetlands: Impact of aeration mode and influent chemical oxygen demand to nitrogen ratios.

PubMed

Hou, Jie; Wang, Xin; Wang, Jie; Xia, Ling; Zhang, Yiqing; Li, Dapeng; Ma, Xufa

2018-06-01

This study aimed at assessing the influence of aeration mode and influent COD/N ratio on nitrogen removal in constructed wetlands (CWs). The results showed that a simultaneous partial nitrification, anammox and denitrification (SNAD) process was established in the intermittent aerated V1. While nitrogen removal pathway gradually changed from partial nitrification-denitrification to complete nitrification-denitrification along with reducing COD/N ratio in the continuous limited aerated V2. Effective inhibition of NOBs under intermittent aeration conditions, good retention of anammox bacteria biomass and much faster depletion of COD prior to substantial NH 4 + -N conversion jointly led to the successful achievement of stable SNDA process with elevated influent COD/N ratios in V1. Furthermore, the presence of SNAD ensured a robust ammonium (84-92%) and TN (80-91%) removal efficiency in V1 under varying COD loading rates. In contrast, the TN removal efficiency decreased rapidly along with the reducing influent COD/N ratios in V2. Copyright © 2018 Elsevier Ltd. All rights reserved.

Optimizing TOC and COD removal for the biodiesel wastewater by electrocoagulation

NASA Astrophysics Data System (ADS)

Tanattı, N. Pınar; Şengil, İ. Ayhan; Özdemir, Abdil

2018-05-01

In this study, the chemical oxygen demand (COD) and the total organic carbon content (TOC) in biodiesel wastewater iron and aluminum electrodes arranged in a bipolar position. In the EC of the biodiesel wastewater, the effects of the supporting electrolyte, initial pH, electrolysis time and current density were examined. The results showed that the majority of the pollutants in the biodiesel wastewater were effectively removed when the iron or aluminum electrodes were used as a sacrificial anode. The highest COD and TOC removal efficiencies were successfully obtained with the iron electrode. COD removal efficiencies are 91.74 and 90.94% for iron and aluminum electrode, respectively. In the same way, TOC removal efficiencies were obtained as 91.79 and 91.98% for the iron and aluminum electrodes, respectively, at initial pH of 6, the current density of 0.3226 mA/cm2, NaCl concentration 1 g/L and 1 min of operating time.

Removal of pharmaceuticals and organic matter from municipal wastewater using two-stage anaerobic fluidized membrane bioreactor.

PubMed

Dutta, Kasturi; Lee, Ming-Yi; Lai, Webber Wei-Po; Lee, Chien Hsien; Lin, Angela Yu-Chen; Lin, Cheng-Fang; Lin, Jih-Gaw

2014-08-01

The aim of present study was to treat municipal wastewater in two-stage anaerobic fluidized membrane bioreactor (AFMBR) (anaerobic fluidized bed reactor (AFBR) followed by AFMBR) using granular activated carbon (GAC) as carrier medium in both stages. Approximately 95% COD removal efficiency could be obtained when the two-stage AFMBR was operated at total HRT of 5h (2h for AFBR and 3h for AFMBR) and influent COD concentration of 250mg/L. About 67% COD and 99% TSS removal efficiency could be achieved by the system treating the effluent from primary clarifier of municipal wastewater treatment plant, at HRT of 1.28h and OLR of 5.65kg COD/m(3)d. The system could also effectively remove twenty detected pharmaceuticals in raw wastewaters with removal efficiency in the range of 86-100% except for diclofenac (78%). No other membrane fouling control was required except scouring effect of GAC for flux of 16LMH. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tertiary treatment of textile wastewater with combined media biological aerated filter (CMBAF) at different hydraulic loadings and dissolved oxygen concentrations.

PubMed

Liu, Fang; Zhao, Chao-Cheng; Zhao, Dong-Feng; Liu, Guo-Hua

2008-12-15

An up-flow biological aerated filter packed with two layers media was employed for tertiary treatment of textile wastewater secondary effluent. Under steady state conditions, good performance of the reactor was achieved and the average COD, NH(4)(+)-N and total nitrogen (TN) in the effluent were 31, 2 and 8mg/L, respectively. For a fixed dissolved oxygen (DO) concentration, an increase of hydraulic loading resulted in a decrease in substrate removal. With the increase of hydraulic loadings from 0.13 to 0.78m(3)/(m(2)h), the removal efficiencies of COD, NH(4)(+)-N and TN all decreased, which dropped from 52 to 38%, from 90 to 68% and from 45 to 33%, respectively. In addition, the results also confirmed that the increase of COD and NH(4)(+)-N removal efficiencies resulted from the increase of DO concentrations, but this variation trend was not observed for TN removal. With the increase of DO concentrations from 2.4 to 6.1mg/L, the removal efficiencies of COD and NH(4)(+)-N were 39-53% and 64-88%, whenas TN removal efficiencies increased from 39 to 42% and then dropped to 35%.

Performance of an anaerobic membrane bioreactor for pharmaceutical wastewater treatment.

PubMed

Svojitka, Jan; Dvořák, Lukáš; Studer, Martin; Straub, Jürg Oliver; Frömelt, Heinz; Wintgens, Thomas

2017-04-01

Anaerobic treatment of wastewater and waste organic solvents originating from the pharmaceutical and chemical industries was tested in a pilot anaerobic membrane bioreactor, which was operated for 580days under different operational conditions. The goal was to test the long-term treatment efficiency and identify inhibitory factors. The highest COD removal of up to 97% was observed when the influent concentration was increased by the addition of methanol (up to 25gL -1 as COD). Varying and generally lower COD removal efficiency (around 78%) was observed when the anaerobic membrane bioreactor was operated with incoming pharmaceutical wastewater as sole carbon source. The addition of waste organic solvents (>2.5gL -1 as COD) to the influent led to low COD removal efficiency or even to the breakdown of anaerobic digestion. Changes in the anaerobic population (e.g., proliferation of the genus Methanosarcina) resulting from the composition of influent were observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical or electrochemical techniques, followed by ion exchange, for recycle of textile dye wastewater.

PubMed

Raghu, S; Ahmed Basha, C

2007-10-22

This paper examines the use of chemical or electrocoagulation treatment process followed by ion-exchange process of the textile dye effluent. The dye effluent was treated using polymeric coagulant (cationic dye-fixing agent) or electrocoagulation (iron and aluminum electrode) process under various conditions such as various current densities and effect of pH. Efficiencies of COD reduction, colour removal and power consumption were studied for each process. The chemical or electrochemical treatment are indented primarily to remove colour and COD of wastewater while ion exchange is used to further improve the removal efficiency of the colour, COD, Fe concentration, conductivity, alkalinity and total dissolved solids (TDS). From the results chemical coagulation, maximum COD reduction of about 81.3% was obtained at 300 mg/l of coagulant whereas in electrocoagulation process, maximum COD removal of about 92.31% (0.25 A/dm2) was achieved with energy consumption of about 19.29 k Wh/kg of COD and 80% (1A/dm(2)) COD removal was obtained with energy consumption of about 130.095 k Wh/kg of COD at iron and aluminum electrodes, respectively. All the experimental results, throughout the present study, have indicated that chemical or electrocoagulation treatment followed by ion-exchange methods were very effective and were capable of elevating quality of the treated wastewater effluent to the reuse standard of the textile industry.

Comparison of COD removal from pharmaceutical wastewater by electrocoagulation, photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes.

PubMed

Farhadi, Sajjad; Aminzadeh, Behnoush; Torabian, Ali; Khatibikamal, Vahid; Alizadeh Fard, Mohammad

2012-06-15

This work makes a comparison between electrocoagulation (EC), photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes to investigate the removal of chemical oxygen demand (COD) from pharmaceutical wastewater. The effects of operational parameters such as initial pH, current density, applied voltage, amount of hydrogen peroxide and electrolysis time on COD removal efficiency were investigated and the optimum operating range for each of these operating variables was experimentally determined. In electrocoagulation process, the optimum values of pH and voltage were determined to be 7 and 40 V, respectively. Desired pH and hydrogen peroxide concentration in the Fenton-based processes were found to be 3 and 300 mg/L, respectively. The amounts of COD, pH, electrical conductivity, temperature and total dissolved solids (TDS) were on-line monitored. Results indicated that under the optimum operating range for each process, the COD removal efficiency was in order of peroxi-electrocoagulation > peroxi-photoelectrocoagulation > photoelectrocoagulation>electrocoagulation. Finally, a kinetic study was carried out using the linear pseudo-second-order model and results showed that the pseudo-second-order equation provided the best correlation for the COD removal rate. Copyright © 2012 Elsevier B.V. All rights reserved.

The role of COD/N ratio on the start-up performance and microbial mechanism of an upflow microaerobic reactor treating piggery wastewater.

PubMed

Meng, Jia; Li, Jiuling; Li, Jianzheng; Astals, Sergi; Nan, Jun; Deng, Kaiwen; Antwi, Philip; Xu, Pianpian

2018-07-01

This study investigated the role of COD/N ratio on the start-up and performance of an upflow microaerobic sludge reactor (UMSR) treating piggery wastewater at 0.5 mgO 2 /L. At high COD/N ratio (6.24 and 4.52), results showed that the competition for oxygen between ammonia-oxidizing bacteria, nitrite-oxidizing bacteria and heterotrophic bacteria limited the removal of nitrogen. Nitrogen removal efficiency was below 40% in both scenarios. Decreasing the influent COD/N ratio to 0.88 allowed achieving high removal efficiencies for COD (∼75%) and nitrogen (∼85%) due to the lower oxygen consumption for COD mineralization. Molecular biology techniques showed that nitrogen conversion at a COD/N ratio 0.88 was dominated by the anammox pathway and that Candidatus Brocadia sp. was the most important anammox bacteria in the reactor with a relative abundance of 58.5% among the anammox bacteria. Molecular techniques also showed that Nitrosomonas spp. was the major ammonia-oxidiser bacteria (relative abundance of 86.3%) and that denitrification via NO 3 - and NO 2 - also contributed to remove nitrogen from the system. Copyright © 2018 Elsevier Ltd. All rights reserved.

High-rate activated sludge system for carbon management--Evaluation of crucial process mechanisms and design parameters.

PubMed

Jimenez, Jose; Miller, Mark; Bott, Charles; Murthy, Sudhir; De Clippeleir, Haydee; Wett, Bernhard

2015-12-15

The high-rate activated sludge (HRAS) process is a technology suitable for the removal and redirection of organics from wastewater to energy generating processes in an efficient manner. A HRAS pilot plant was operated under controlled conditions resulting in concentrating the influent particulate, colloidal, and soluble COD to a waste solids stream with minimal energy input by maximizing sludge production, bacterial storage, and bioflocculation. The impact of important process parameters such as solids retention time (SRT), hydraulic residence time (HRT) and dissolved oxygen (DO) levels on the performance of a HRAS system was demonstrated in a pilot study. The results showed that maximum removal efficiencies of soluble COD were reached at a DO > 0.3 mg O2/L, SRT > 0.5 days and HRT > 15 min which indicates that minimizing the oxidation of the soluble COD in the high-rate activated sludge process is difficult. The study of DO, SRT and HRT exhibited high degree of impact on the colloidal and particulate COD removal. Thus, more attention should be focused on controlling the removal of these COD fractions. Colloidal COD removal plateaued at a DO > 0.7 mg O2/L, SRT > 1.5 days and HRT > 30 min, similar to particulate COD removal. Concurrent increase in extracellular polymers (EPS) production in the reactor and the association of particulate and colloidal material into sludge flocs (bioflocculation) indicated carbon capture by biomass. The SRT impacted the overall mass and energy balance of the high-rate process indicating that at low SRT conditions, lower COD mineralization or loss of COD content occurred. In addition, the lower SRT conditions resulted in higher sludge yields and higher COD content in the WAS. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhanced nitrogen removal from piggery wastewater with high NH4+ and low COD/TN ratio in a novel upflow microaerobic biofilm reactor.

PubMed

Meng, Jia; Li, Jiuling; Li, Jianzheng; Antwi, Philip; Deng, Kaiwen; Nan, Jun; Xu, Pianpian

2018-02-01

To enhance nutrient removal more cost-efficiently in microaerobic process treating piggery wastewater characterized by high ammonium (NH 4 + -N) and low chemical oxygen demand (COD) to total nitrogen (TN) ratio, a novel upflow microaerobic biofilm reactor (UMBR) was constructed and the efficiency in nutrient removal was evaluated with various influent COD/TN ratios and reflux ratios. The results showed that the biofilm on the carriers had increased the biomass in the UMBR and enhanced the enrichment of slow-growth-rate bacteria such as nitrifiers, denitrifiers and anammox bacteria. The packed bed allowed the microaerobic biofilm process perform well at a low reflux ratio of 35 with a NH 4 + -N and TN removal as high as 93.1% and 89.9%, respectively. Compared with the previously developed upflow microaerobic sludge reactor, the UMBR had not changed the dominant anammox approach to nitrogen removal, but was more cost-efficiently in treating organic wastewater with high NH 4 + -N and low COD/TN ratio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined ultrasound and Fenton (US-Fenton) process for the treatment of ammunition wastewater.

PubMed

Li, Yangang; Hsieh, Wen-Pin; Mahmudov, Rovshan; Wei, Xiaomei; Huang, C P

2013-01-15

A wastewater collected from a regional ammunition process site was treated with combined US-Fenton process. Factors such as pH, temperature, reaction time, US energy intensity, initial TOC concentration, and the molar ratio of iron to hydrogen peroxide that might affect the treatment efficiency were investigated. The removal of TOC, COD, and color increased with decreasing pH and increasing temperature and US intensity. Color was removed rapidly reaching 85% in 10 min; whereas TOC and COD were removed slowly, only about 20% for both in 10 min and approaching 65 and 92% removal in 120 min, respectively. The optimal molar ratio of Fe(II) to H(2)O(2) for TOC and COD removal was 500. The results showed that the change in the average carbon oxidation number (ACON) was parallel to that of the removal efficiency of TOC, COD, and color. The toxicity of treated wastewater was reduced as assessed by the respiration rate of Escherichia coli. Copyright © 2013 Elsevier B.V. All rights reserved.

[Electricity generation from sweet potato fuel ethanol wastewater using microbial fuel cell technology].

PubMed

Cai, Xiao-Bo; Yang, Yi; Sun, Yan-Ping; Zhang, Liang; Xiao, Yao; Zhao, Hai

2010-10-01

Air cathode microbial fuel cell (MFC) were investigated for electricity production from sweet potato fuel ethanol wastewater containing 5000 mg/L of chemical oxygen demand (COD). Maximum power density of 334.1 mW/m2, coulombic efficiency (CE) of 10.1% and COD removal efficiency of 92.2% were approached. The effect of phosphate buffer solution (PBS) and COD concentration on the performance of MFC was further examined. The addition of PBS from 50 mmol/L to 200 mmol/L increased the maximum power density and CE by 33.4% and 26.0%, respectively. However, the COD removal efficiency was not relative to PBS concentration in the wastewater. When the COD increased from 625 mg/L to 10 000 mg/L, the maximum value of COD removal efficiency and the maximum power density were gained at the wastewater strength of 5 000 mg/L. But the CE ranged from 28.9% to 10.3% with a decreasing trend. These results demonstrate that sweet potato fuel ethanol wastewater can be used for electricity generation in MFC while at the same time achieving wastewater treatment. The increasing of PBS concentration can improve the power generation of MFC. The maximum power density of MFC increases with the rise of COD concentration, but the electricity generation will decrease for the acidification of high wastewater concentration.

[Treatment of Urban Runoff Pollutants by a Multilayer Biofiltration System].

PubMed

Wang, Xiao-lu; Zuo, Jian-e; Gan, Li-li; Xing, Wei; Miao, Heng-feng; Ruan, Wen-quan

2015-07-01

In order to control the non-point source pollution from road runoff in Wuxi City effectively, a multilayer biofiltration system was designed to remove a variety of pollutants according to the characteristics of road runoff in Wuxi, and the experimental research was carried out to study the effect on rainwater pollution purification. The results show that the system has a good performance on removing suspended solids (SS), organic pollutant (COD), nitrogen and phosphorus: all types of multilayer biofiltration systems have a high removal rate for SS, which can reach 90%. The system with activated carbon (GAC) has higher removal rates for COD and phosphorus. The system with zeolite (ZFM) has a relatively better removal efficiency for nitrogen. The addition of wood chips in the system can significantly improve the system efficiency for nitrogen removal. Between the two configurations of layered and distributed wood chips, configurations of distributed wood chips reach higher COD, phosphorus and nitrogen pollutants removal efficiencies since they can reduce the release of wood chips dissolution.

Pretreatment of bakery wastewater by coagulation-flocculation and dissolved air flotation.

PubMed

Liu, J C; Lien, C S

2001-01-01

The pretreatment of wastewater from a large-scale bakery was studied. In the coagulation-flocculation reaction, it was found that both alum and FeCl3 were effective in the jar tests. When at coagulant dosage of 90 to 100 mg/l, 55% of COD and 95 to 100% of SS could be removed. The optimum pH was at 6.0. In addition, the removal of SS was affected by pH more significantly, while the removal of COD was not affected in the pH range of 6.0 to 8.0. In the DAF experiments, 48.6% of COD and 69.8% of SS were removed in 10 min at a pressure of 4 kg/cm2, recycle ratio of 0.3 l/min, and pH of 6.0. Upon the addition of 100 mg/l of alum, the removal efficiency of COD did not increase while SS removal increased to 82.1%. It was found that 5-min flocculation time did improve the COD removal while it had little effect on SS removal. Flocculation for longer than 5 min did not enhance the flotation performance. Similar phenomena were observed when FeCl3 was used as the coagulant, except that flocculation had an insignificant effect on COD and SS removal. It was also found that FeCl3 was relatively more effective than alum. In summary, both coagulation-flocculation and DAF were efficient for the pretreatment. The advantages and disadvantages were discussed.

Sewage treatment in integrated system of UASB reactor and duckweed pond and reuse for aquaculture.

PubMed

Mohapatra, D P; Ghangrekar, M M; Mitra, A; Brar, S K

2012-06-01

The performance of a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and a duckweed pond containing Lemna gibba was investigated for suitability for treating effluent for use in aquaculture. While treating low-strength sewage having a chemical oxygen demand (COD) of typically less than 200 mg/L, with an increase in hydraulic retention time (HRT) from 10.04 to 33.49 h, COD removal efficiency of the UASB reactor decreased owing to a decrease in organic loading rate (OLR) causing poor mixing in the reactor. However, even at the lower OLR (0.475 kg COD/(m3 x d)), the UASB reactor gave a removal efficiency of 68% for COD and 74% for biochemical oxygen demand (BOD). The maximum COD, BOD, ammonia-nitrogen and phosphate removal efficiencies of the duckweed pond were 40.77%, 38.01%, 61.87% and 88.57%, respectively. Decreasing the OLR by increasing the HRT resulted in an increase in efficiency of the duckweed pond for removal of ammonia-nitrogen and phosphate. The OLR of 0.005 kg COD/(m2 x d) and HRT of 108 h in the duckweed pond satisfied aquaculture quality requirements. A specific growth rate of 0.23% was observed for tilapia fish fed with duckweed harvested from the duckweed pond. The economic analysis proved that it was beneficial to use the integrated system of a UASB reactor and a duckweed pond for treatment of sewage.

An integrated anaerobic digestion and UV photocatalytic treatment of distillery wastewater.

PubMed

Apollo, Seth; Onyango, Maurice S; Ochieng, Aoyi

2013-10-15

Anaerobic up-flow fixed bed reactor and annular photocatalytic reactor were used to study the efficiency of integrated anaerobic digestion (AD) and ultraviolet (UV) photodegradation of real distillery effluent and raw molasses wastewater (MWW). It was found that UV photodegradation as a stand-alone technique achieved colour removal of 54% and 69% for the distillery and MWW, respectively, with a COD reduction of <20% and a negligible BOD reduction. On the other hand, AD as a single treatment technique was found to be effective in COD and BOD reduction with efficiencies of above 75% and 85%, respectively, for both wastewater samples. However, the AD achieved low colour removal efficiency, with an increase in colour intensity of 13% recorded when treating MWW while a colour removal of 51% was achieved for the distillery effluent. The application of UV photodegradation as a pre-treatment method to the AD process reduced the COD removal and biogas production efficiency. However, an integration in which UV photodegradation was employed as a post-treatment to the AD process achieved high COD removal of above 85% for both wastewater samples, and colour removal of 88% for the distillery effluent. Thus, photodegradation can be employed as a post-treatment technique to an AD system treating distillery effluent for complete removal of the biorecalcitrant and colour imparting compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparison between a moving bed membrane bioreactor and a conventional membrane bioreactor on organic carbon and nitrogen removal.

PubMed

Yang, Shuai; Yang, Fenglin; Fu, Zhimin; Lei, Ruibo

2009-04-01

A membrane bioreactor filled with carriers instead of activated sludge named a moving bed membrane bioreactor (MBMBR) was investigated for simultaneously removing organic carbon and nitrogen in wastewater. Its performance was compared with a conventional membrane bioreactor (CMBR) at various influent COD/TN ratios of 8.9-22.1. The operational parameters were optimized to increase the treatment efficiency. COD removal efficiency averaged at 95.6% and 96.2%, respectively, for MBMBR and CMBR during the 4 months experimental period. The MBMBR system demonstrated good performance on nitrogen removal at different COD/TN ratios. When COD/TN was 8.9 and the total nitrogen (TN) load was 7.58 mg/l h, the TN and ammonium nitrogen removal efficiencies of the MBMBR were maintained over 70.0% and 80.0%, respectively, and the removed total nitrogen (TN) load reached to 5.31 mg/l h. Multifunctional microbial reactions in the carrier, such as simultaneous nitrification and denitrification (SND), play important roles in nitrogen removal. In comparison, the CMBR did not perform so well. Its TN removal was not stable, and the removed total nitrogen (TN) load was only 1.02 mg/l h at COD/TN ratio 8.9. The specific oxygen utilization rate (SOUR) showed that the biofilm has a better microbial activity than an activated sludge. Nevertheless, the membrane fouling behavior was more severe in the MBMBR than in the CMBR due to a thick and dense cake layer formed on the membrane surface, which was speculated to be caused by the filamentous bacteria in the MBMBR.

Removal of carbon, nitrogen and phosphorus from the separated liquid phase of hog manure by the multi-zone BioCAST technology.

PubMed

Yerushalmi, Laleh; Alimahmoodi, Mahmood; Afroze, Niema; Godbout, Stephane; Mulligan, Catherine N

2013-06-15

The removal of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) at concentrations of 960 ± 38 to 2400 ± 96 mg/L, 143 ± 9 to 235 ± 15 mg/L and 25 ± 2 to 57 ± 4 mg/L, respectively, from the separated liquid phase of hog manure by the multi-zone BioCAST technology is discussed. Despite the inhibitory effect of hog waste toward microbial activities, removal efficiencies up to 89.2% for COD, 69.2% for TN and 47.6% for TP were obtained during 185 d of continuous operation. The free ammonia inhibition was postulated to be responsible for the steady reduction of COD and TP removal with the increase of TN/TP ratio from 3.6 to 5.8. On the contrary, the increase of COD/TN ratio from 4.8 to 14.1 improved the removal of all contaminants. Nitrogen removal did not show any dependence on the COD/TP ratio, despite the steady increase of COD and TP removal with this ratio in the range of 19.3-50.6. The removal efficiencies of organic and inorganic contaminants increased progressively owing to the adaptation of microbial biomass, resulting from the presence of suspended biomass in the mixed liquor that circulated continuously between the three zones of aerobic, microaerophilic and anoxic, as well as the attached biomass immobilized inside the aerobic zone. Copyright © 2013 Elsevier B.V. All rights reserved.

Shrimp pond wastewater treatment using pyrolyzed chicken feather as adsorbent

NASA Astrophysics Data System (ADS)

Moon, Wei Chek; Jbara, Mohamad Hasan; Palaniandy, Puganeshwary; Yusoff, Mohd Suffian

2017-10-01

In this study, chicken feather fiber was used as a raw material to prepare a non-expensive adsorbent by pyrolysis without chemical activation. The main pollutants treated in this study were chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N) from shrimp pond wastewater containing high concentrations of nutrients, which caused the eutrophication phenomenon in adjacent water. Batch adsorption studies were performed to investigate the effect of pH (5-8), mass of adsorbent (0.5-3 g), and shaking time (0.5-2 h) on the removal efficiency of COD and NH3- N. Experimental results showed that the optimum conditions were as follows: pH 5, 0.5 g of adsorbent, and 0.5 h of shaking. Under these conditions, 34.01% and 40.47% of COD and NH3-N were removed, respectively, from shrimp pond wastewater. The adsorption processes were best described by the Langmuir isotherm model for COD and NH3-N removal, with maximum monolayer adsorption capacity of 36.9 and 7.24 mg/g for COD and NH3-N, respectively. The results proved that chicken feather could remove COD and NH3-N from shrimp pond wastewater. However, further studies on thermal treatment should be carried out to increase the removal efficiency of pyrolyzed chicken feather fiber.

Synergic treatment for monosodium glutamate wastewater by Saccharomyces cerevisiae and Coriolus versicolor.

PubMed

Jia, Cuiying; Kang, Ruijuan; Zhang, Yuhui; Cong, Wei; Cai, Zhaoling

2007-03-01

Biodegradation and decolorization of monosodium glutamate wastewater were carried out by using an acidophilus yeast strain of Saccharomyces cerevisiae and Coriolus versicolor. For the yeast treatment, the highest COD removal and reducing sugar removal efficiency were 76.6% and 80.2%, respectively. The color removal was only 2%. For C. versicolor treatment, the highest COD removal, color removal and reducing sugar removal efficiencies were 78.7%, 56.5% and 90.9%, respectively. The synergic treatment process, in which the yeast and C. versicolor were successively applied,exhibited great advantage over the individual process.

Cosmetic wastewater treatment by the ZVI/H2O2 process.

PubMed

Bogacki, Jan; Marcinowski, Piotr; Zapałowska, Ewa; Maksymiec, Justyna; Naumczyk, Jeremi

2017-10-01

The ZVI/H 2 O 2 process was applied for cosmetic wastewater treatment. Two commercial zero-valent iron (ZVI) types with different granulations were chosen: Hepure Ferrox PRB and Hepure Ferrox Target. In addition, the pH and stirring method influence on ZVI/H 2 O 2 process efficiency was studied. During the ZVI and ZVI/H 2 O 2 processes, linear Fe ions concentration increase was observed. The addition of H 2 O 2 significantly accelerated the iron dissolution process. The highest COD removal was obtained using finer ZVI (Hepure Ferrox Target) for doses of reagents ZVI/H 2 O 2 1500/1600 mg/L, in a H 2 O 2 /COD weight ratio 2:1, at pH 3.0 with stirring on a magnetic stirrer. After 120 min of the process, 84.0% COD removal (from 796 to 127 mg/L) was achieved. It was found that the efficiency of the process depends, as in the case of the Fenton process, on the ratio of the reagents (ZVI/H 2 O 2 ) and their dose in relation to the COD (H 2 O 2 /COD) but does not depend on the dose of the iron itself. Statistical analysis confirms that COD removal efficiency depends primarily on H 2 O 2 /COD ratio and ZVI granulation, but ZVI dose influence is not statistically significant. The head space, solid-phase microextraction, gas chromatography, mass spectrometry results confirm high efficiency of the ZVI/H 2 O 2 process.

Natural attenuation, biostimulation and bioaugmentation of landfill leachate management

NASA Astrophysics Data System (ADS)

Er, X. Y.; Seow, T. W.; Lim, C. K.; Ibrahim, Z.

2018-04-01

Landfills used for solid waste management will lead to leachate production. Proper leachate management is highly essential to be paid attention to protect the environment and living organisms’ health and safety. In this study, the remedial strategies used for leachate management were natural attenuation, biostimulation and bioaugmentation. All treatment samples were treated via 42-days combined anaerobic-aerobic treatment and the treatment efficiency was studied by measuring the removal rate of COD and ammonia nitrogen. In this study, all remedial strategies showed different degrees of contaminants removal. Lowest contaminants removal rate was achieved via bioaugmentation of B. panacihumi strain ZB1, which were 39.4% of COD and 37.6% of ammonia nitrogen removed from the leachate sample. Higher contaminants removal rate was achieved via natural attenuation and biostimulation. Native microbial population was able to remove 41% of COD and 59% of ammonia nitrogen from the leachate sample. The removal efficiency could be further improved via biostimulation to trigger microbial growth and decontamination rate. Through biostimulation, 58% of COD and 51.8% of ammonia nitrogen were removed from the leachate sample. In conclusion, natural attenuation and biostimulation should be the main choice for leachate management to avoid any unexpected impacts due to introduction of exogenous species.

Sono assisted electrocoagulation process for the removal of pollutant from pulp and paper industry effluent.

PubMed

Asaithambi, P; Aziz, Abdul Raman Abdul; Sajjadi, Baharak; Daud, Wan Mohd Ashri Bin Wan

2017-02-01

In the present work, the efficiency of the sonication, electrocoagulation, and sono-electrocoagulation process for removal of pollutants from the industrial effluent of the pulp and paper industry was compared. The experimental results showed that the sono-electrocoagulation process yielded higher pollutant removal percentage compared to the sonication and electrocoagulation process alone. The effect of the operating parameters in the sono-electrocoagulation process such as electrolyte concentration (1-5 g/L), current density (1-5 A/dm 2 ), effluent pH (3-11), COD concentration (1500-6000 mg/L), inter-electrode distance (1-3 cm), and electrode combination (Fe and Al) on the color removal, COD removal, and power consumption were studied. The maximum color and COD removal percentages of 100 and 95 %, respectively, were obtained at the current density of 4 A/dm 2 , electrolyte concentration of 4 g/L, effluent pH of 7, COD concentration of 3000 mg/L, electrode combination of Fe/Fe, inter-electrode distance of 1 cm, and reaction time of 4 h, respectively. The color and COD removal percentages were analyzed by using an UV/Vis spectrophotometer and closed reflux method. The results showed that the sono-electrocoagulation process could be used as an efficient and environmental friendly technique for complete pollutant removal.

Start-up of an UASB-septic tank for community on-site treatment of strong domestic sewage.

PubMed

Al-Shayah, Mohammad; Mahmoud, Nidal

2008-11-01

Two community on-site UASB-septic tanks were operated in parallel over a six months period under two different hydraulic retention times (HRT) of 2 days for R1 and 4 days for R2 at mean sewage temperature of 24 degrees C. The sewage was characterised by a high COD(tot) concentration of 1189 mg/L, with a large fraction of COD(sus), viz. 54%. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), BOD5 and TSS were "56%, 87%, 59% and 81%" and "58%, 90%, 60% and 82%" for both systems, respectively. R2 achieved a marginal but significant (p<0.05) better removal efficiencies of those parameters as compared to R1. The COD(col) and COD(dis) removals in R1 and R2 were respectively 31% and 20%, and 34% and 22%. The sludge accumulation was very low suggesting that the desludging frequency will be of several years. Accordingly, the reactor can be adequately designed at 2 days HRT.

Anodic oxidation of slaughterhouse wastewater on boron-doped diamond: process variables effect.

PubMed

Abdelhay, Arwa; Jum'h, Inshad; Abdulhay, Enas; Al-Kazwini, Akeel; Alzubi, Mashael

2017-12-01

A non-sacrificial boron-doped diamond electrode was prepared in the laboratory and used as a novel anode for electrochemical oxidation of poultry slaughterhouse wastewater. This wastewater poses environmental threats as it is characterized by a high content of recalcitrant organics. The influence of several process variables, applied current density, initial pH, supporting electrolyte nature, and concentration of electrocoagulant, on chemical oxygen demand (COD) removal, color removal, and turbidity removal was investigated. Results showed that raising the applied current density to 3.83 mA/cm 2 has a positive effect on COD removal, color removal, and turbidity removal. These parameters increased to 100%, 90%, and 80% respectively. A low pH of 5 favored oxidants generation and consequently increased the COD removal percentage to reach 100%. Complete removal of COD had occurred in the presence of NaCl (1%) as supporting electrolyte. Na 2 SO 4 demonstrated lower efficiency than NaCl in terms of COD removal. The COD decay kinetics follows the pseudo-first-order reaction. The simultaneous use of Na 2 SO 4 and FeCl 3 decreased the turbidity in wastewater by 98% due to electrocoagulation.

[Research on the treatment of wastewater containing PVA by ozonation-activated sludge process].

PubMed

Xing, Xiao-Qiong; Huang, Cheng-Lan; Liu, Min; Chen, Ying

2012-11-01

The wastewater containing polyvinyl alcohol (PVA) was characterized with poor biodegradability, and was difficult to remove. In order to find an economically reasonable and practical technology, the research on the removal efficiency of different concentration wastewater containing PVA by ozonation-activated sludge process was studied, and the result was compared with the traditional activated sludge process. The results showed that the ozonation-activated sludge process was not suitable for treating influent with COD below 500 mg x L(-1) and the wastewater PVA concentration was 10-30 mg x L(-1). When the influent COD was between 500-800 mg x L(-1) and the PVA concentration was 15-60 mg x L(-1), the system had advantages on dealing with this kind of wastewater, and the average removal efficiency of COD and PVA were 92.8% and 57.4%, which were better than the traditional activated sludge process 4.1% and 15.2% respectively. In addition, the effluent concentrations of COD could keep between 30-60 mg x L(-1). When the influent COD was 1 000-1 200 mg x L(-1) and the PVA concentration was 20-70 mg x L(-1), the average removal efficiencies of COD and PVA were 90.9% and 45.3%, which were better than the traditional activated sludge process 12.8% and 12.1% respectively, but the effluent should to be further treated. Compared with the traditional activated sludge process, ozonation-activated sludge process had high treatment efficiency, stable running effect, and effectively in dealing with industrial wastewater containing PVA.

Evaluation of the impact of organic material on the anaerobic methane and ammonium removal in a membrane aerated biofilm reactor (MABR) based on the multispecies biofilm modeling.

PubMed

Wu, Jun; Zhang, Yue

2017-01-01

The simultaneous nitrogen and methane removal by the combined nitritation, anaerobic ammonium oxidation (anammox), and nitrite dependent anaerobic methane oxidation (n-damo) processes in the membrane aerated biofilm reactor (MABR) offers clear advantages in term of energy saving and greenhouse gas emission mitigation. The rejected water from sludge digestion usually contained high ammonium, COD, and dissolved methane. The impact of influent COD on the anaerobic methane and ammonium removal in an MABR was evaluated in the model based study. The results indicated that the influent COD did not reduce the methane and ammonium removal efficiency at C/N ratio (influent COD/NH 4 + -N) less than 0.1. At high C/N ratio, the oxygen transfer coefficient needed to be increased to achieve high methane and nitrogen removal. Substrate flux analysis indicated that heterotrophic denitrification in the outside layer of biofilm reduced the impact of influent COD. Heterotrophic growth needed to be limited at the outside layer by using NO 3 - as electron acceptor; otherwise, the heterotrophic bacteria would compete NO 2 - and space with anammox and n-damo bacteria in the inner layers and reduce the nitrogen and methane removal efficiency.

Application of integrated ozone and granular activated carbon for decolorization and chemical oxygen demand reduction of vinasse from alcohol distilleries.

PubMed

Hadavifar, Mojtaba; Younesi, Habibollah; Zinatizadeh, Ali Akbar; Mahdad, Faezeh; Li, Qin; Ghasemi, Zahra

2016-04-01

This study investigates the treatment of the distilleries vinasse using a hybrid process integrating ozone oxidation and granular activated carbons (GAC) in both batch and continuous operation mode. The batch-process studies have been carried out to optimize initial influent pH, GAC doses, the effect of the ozone (O3) and hydrogen peroxide (H2O2) concentrations on chemical oxygen demand (COD) and color removal of the distilleries vinasse. The continuous process was carried out on GAC and ozone treatment alone as well as the hybrid process comb both methods to investigate the synergism effectiveness of the two methods for distilleries vinasse COD reduction and color removal. In a continuous process, the Yan model described the experimental data better than the Thomas model. The efficiency of ozonation of the distilleries vinasse was more effective for color removal (74.4%) than COD removal (25%). O3/H2O2 process was not considerably more effective on COD and color removal. Moreover, O3/GAC process affected negatively on the removal efficiency by reducing COD and color from distilleries vinasse. The negative effect decreased by increasing pH value of the influent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks.

PubMed

Elmitwalli, T A; Sayed, S; Groendijk, L; van Lier, J; Zeeman, G; Lettinga, G

2003-01-01

The decentralised treatment of concentrated sewage (about 3,600 mgCOD/l) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m3). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each reactor. The system was fed with concentrated domestic sewage, mainly black water from about 40 toilets flushed with only 4 litre of water and a limited amount of grey water. The system showed high removal efficiency for the different COD fractions. Mean removal efficiencies in the two-step AH-septic tank at 5 days HRT and 13 degrees C were 94, 98, 74 and 78% for total COD, suspended COD, colloidal COD and dissolved COD respectively. The results of short run experiments indicated that the presence of reticulated polyurethane foam (RPF) media in the AH-septic tank improved the removal of suspended COD by 22%. The first AH-septic tank was full of sludge after 4 months of operation due to the high removal of particulate COD and the limited hydrolysis at low temperature conditions. Therefore, a simple mathematical model was developed based on ADM1 (the IWA model in 2002). Based on the experimental results and the mathematical model, only a one-step AH septic tank is required. An HRT of 5.5-7.5 days is needed for that one-step AH septic tank to treat concentrated sewage at a low temperature of 13 degrees C. Such a system can provide a total COD removal as high as 87% and will be full of sludge after a period of more than a year.

Removal of High -Concentration and Refractory Organic Matter from Diosgenin Manufacture Wastewater : a case study of a demonstration project in Hubei Province, P R China

NASA Astrophysics Data System (ADS)

Bao, J.; Wang, L.

2009-12-01

Wastewater from diosgenin manufacture is dark brown (3,500 ~4,000 times of the chroma) and acidic(pH=0.8~1.5)with high concentration of organic matter(COD=25,000~38,000 mg/L)and poor biodegradability(BOD5/COD= 0.25~0.30). It is highly toxic to biota due to the water-soluble saponin, tannins and pectin. Therefore removal of the organic matter is of great importance before the discharge of the wastewater into the environment. Here we presented a set of data from a demonstration project in Hubei province, P R China with an improved technics. This technics, focusing on the treatment of diosgenin wastewater, included hydrolytic acidification, internal electrolysis, neutralization, aerating-improved Up-flow Anaerobic Sludge Bed (UASB) and bio-contact oxidation treatment in sequence to remove the organic matter. After 60 days of starting-up, the water quality from hydrolytic acidification reactor was greatly improved. The effluent became clear, indicating the obvious removal of suspended solids in the water; the ratio of BOD/COD increased to 0.44, suggesting an significant increase of biodegradability; the content of volatile fatty acid (VFA) increased from 22.6 mmol/L to 86.8 mmol/L and the volume loading of COD reached 9.48 kg COD/(m3d). Basically at this stage the removal efficiency of COD was stabilized at 25%. Further treatment was conducted on the effluent from hydrolytic acidification reactor through the Improved UASB Reactor after the internal electrolysis and neutralization. The Improved UASB Reactor can start up at room temperature with an influent of 1,500 mg/L COD and inflow rate of 50(m3/d). Then, temperature was increased gradually to 38 oC (± 2 oC) to optimize the growth of the mesophilic anaerobes in the reactor. The content of VFA of the effluent was controlled below 8 mmol/L to guarantee the pH in the range of 6.8~7.2. After 150 days of debugging, the COD of the influent to UASB increased to 9,600 mg/L, hydraulic retaining time (HRT) was around 70 hrs , the volume loading and the removal efficiency of COD reached 3.42 kg COD/(m3.d) and 75% respectively. Bio-contact oxidation process dealt with the effluent from the Improved UASB at room temperature. The HRT was 54 hrs and dissolved oxygen was controlled between 2 to 4 mg/L. Currently, the COD volume loading reached 1.05 kg COD/(m3.d) and the removal efficiency of COD was over 90%. The total removal efficiencies of COD and color were over 99% and 98% respectively in the overall process. The pH, color and COD content of the final effluent were 7, about 200 mg/L and 50 times of the chroma respectively. All these indexes met the criteria of “The National Discharge Standard of Industry Water Pollutants for Sapogenin”(GB 20425-2006). This work was supported by National Key Technologies R&D Program No. 2006BAB04A14-2), the Hubei Provincial Science and Technology Department (No. 2006AA305A05) and Wuhan Science and Technology Bureau (20066002101).

Biodegradation of textile wastewater: enhancement of biodegradability via the addition of co-substrates followed by phytotoxicity analysis of the effluent.

PubMed

Ceretta, María Belén; Durruty, Ignacio; Orozco, Ana Micaela Ferro; González, Jorge Froilán; Wolski, Erika Alejandra

2018-05-01

This work reports on the biodegradation of textile wastewater by three alternative microbial treatments. A bacterial consortium, isolated from a dyeing factory, showed significant efficacy in decolourizing wastewater (77.6 ± 3.0%); the decolourization rate was 5.80 ± 0.31 mg of azo dye·L -1 ·h -1 , without the addition of an ancillary carbon source (W). The degradation was 52% (measured as COD removal) and the products of the treatment showed low biodegradability (COD/BOD 5 = 4.2). When glucose was added to the wastewater, (W + G): the decolourization efficiency increased to 87.24 ± 2.5% and the decolourization rate significantly improved (25.67 ± 3.62 mg·L -1 ·h -1 ), although the COD removal efficiency was only 44%. Finally, the addition of starch (W + S) showed both a similar decolourization rate and efficiency to the W treatment, but a higher COD removal efficiency (72%). In addition, the biodegradability of the treated wastewater was considerably improved (COD/BOD 5 = 1.2) when starch was present. The toxicity of the degradation products was tested on Lactuca sativa seeds. In all treatments, toxicity was reduced with respect to the untreated wastewater. The W + S treatment gave the best performance.

Quali-quantitative characterization and wastewater treatment of a winery located in the mid-west of Santa Catarina state, South of Brazil.

PubMed

Ortigara, A R C; Sezerino, P H; Bento, A P; Scaratti, D

2009-01-01

This paper analyses variations in the quali-quantitative characterization of winery wastewater, and the behavior of the treatment of these effluents. The wastewater produced is sent to two disposition systems: Point A receives the wastewater from the production area whereas Point B receives the wastewater from the area where the washing of bottles takes place. Two Aerated Submerged Biofilter (ASB) reactors (with oyster shells as support material) were built at lab scale to promote the treatment of the winery effluent. Water usage and effluent production values of the 2008 harvest season indicate that grape processing accounted for 30% of the total water usage. The median value found for the effluent at Point A was 8,260 mg COD L(-1) and at Point B 358 mg COD L(-1). The average C/N/P ratio found at Point A was 100/0.29/0.28 during the harvest and 100/0.27/0.25 during the non harvest. For ASB 1 the COD removal efficiency ranged from 56% to 90%, with the removed organic load ranging from 1.5 kg COD m(-3) d(-1) to 2.7 kg COD m(-3) d(-1), respectively. For ASB 2 the COD removal efficiency ranged from 63% to 82%, with the removed organic load ranging from 1.8 kg COD m(-3) d(-1) to 1.7 kg COD m(-3) d(-1), respectively.

Treatment of oily wastewater of a gas refinery by electrocoagulation using aluminum electrodes.

PubMed

Saeedi, Mohesn; Khalvati-Fahlyani, Amin

2011-03-01

Oily wastewaters are the most important discharges of gas refineries from an environmental point-of-view. In the present study, treatment of gas refinery oily wastewater by electrocoagulation using aluminum electrodes was investigated. The effects of electrode distance, initial pH, sodium sulfate (Na2SO4) as a supporting electrolyte, polyaluminum chloride dosage as a coagulant aid, and current density on the efficiency of chemical oxygen demand (COD) removal were examined. The results revealed that the COD removal rate increases by applying more current density and polyaluminum chloride and, to a lesser extent, Na2SO4 dosage. The results also showed that 97% COD can be removed at optimum operational conditions. Specific electrical energy consumption could be reduced from 19.48 kWh (kg COD removal)(-1) to 11.057 kWh (kg COD removal)(-1) using Na2SO4 as a supporting electrolyte. Gas chromatographic analysis of raw and treated wastewater also revealed that most normal hydrocarbons (nearly 99%) were removed during the electrocoagulation process.

Combined System of Activated Sludge and Ozonation for the Treatment of Kraft E1 Effluent

PubMed Central

Assalin, Marcia Regina; dos Santos Almeida, Edna; Durán, Nelson

2009-01-01

The treatment of paper mill effluent for COD, TOC, total phenols and color removal was investigated using combined activated sludge-ozonation processes and single processes. The combined activated sludge-O3/pH 10 treatment was able to remove around 80% of COD, TOC and color from Kraft E1 effluent. For the total phenols, the efficiency removal was around 70%. The ozonation post treatment carried out at pH 8.3 also showed better results than the single process. The COD, TOC, color and total phenols removal efficiency obtained were 75.5, 59.1, 77 and 52.3%, respectively. The difference in the concentrations of free radical produced by activated sludge-O3/pH 10 and activated sludge-O3/pH 8.3 affected mainly the TOC and total phenol removal values. PMID:19440438

Removing Organic Matter and Nutrients from Pig Farm Wastewater with a Constructed Wetland System

PubMed Central

De La Mora-Orozco, Celia; González-Acuña, Irma Julieta; Saucedo-Terán, Ruben Alfonso; Flores-López, Hugo Ernesto; Rubio-Arias, Hector Osbaldo; Ochoa-Rivero, Jesús Manuel

2018-01-01

Pollutants from pig farms in Mexico have caused problems in many surface water reservoirs. Growing concern has driven the search for low-cost wastewater treatment solutions. The objective of this research was to evaluate the potential of an in-series constructed wetland to remove nutrients from wastewater from a pig farm. The wetland system had a horizontal flow that consisted of three cells, the first a surface water wetland, the second a sedimentation cell, and the third a subsurface flow wetland. The vegetation used was Thypa sp. and Scirpus sp. A mix of soil with red volcanic rock (10–30 mm diameter) and yellow sand (2–8 mm diameter) was used as a substrate for the vegetation. The experiments were carried out in duplicate. Water samples were collected at the inflow and outflow of the cells. Two hydraulic retention times (HRT) (5 and 10 days) and three treatments were evaluated: 400, 800, and 1200 mg·L−1 of chemical oxygen demand (COD) concentration. Data was collected in situ for temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), and total dissolved solids (TDS). COD, total Kjeldahl nitrogen (TKN), ammonia nitrogen (NH3–N), and total phosphorous (TP) were analyzed in the laboratory. The results showed that the in-series constructed wetland is a feasible system for nutrient pollutant removal, with COD removal efficiency of 76% and 80% mg·L−1 for a 5- and 10-day HRT, respectively. The removal efficiency for TKN, NH3–N, and TP reached about 70% with a 5-day HRT, while a removal of 85% was obtained with a 10-day HRT. The wetland reached the maximum removal efficiency with a 10-day HRT and an inflow load of 400 mg·L−1 of organic matter. The results indicate that HRT positively affects removal efficiency of COD and TDS. On the other hand, the HRT was not the determining factor for TP removal. Treatment one, with an initial COD concentration of 400 mg·L−1, had the highest removal of the assessed pollutants, allowing for the use of water for irrigation according to Mexican regulatory standards (NOM-001). The water quality resulting from treatments two and three (T2 = 800 mg·L−1 of COD and T3 = 1200 mg·L−1 of COD) did not comply with minimal requirements for irrigation water. PMID:29883370

Coupling of anodic oxidation and adsorption by granular activated carbon for chemical oxygen demand removal from 4,4'-diaminostilbene-2,2'-disulfonic acid wastewater.

PubMed

Wang, Lizhang; Zhao, Yuemin

2010-01-01

Experiments were performed to reduce chemical oxygen demand (COD) from 4,4'-diaminostilbene-2,2'-disulfonic (DSD) acid manufacturing wastewater using electrochemical oxidation coupled with adsorption by granular activated carbon. The COD removal is affected by the residence time and applied voltage. When the residence time is increased, lower value of COD effluent could be obtained, however, the average current efficiency (ACE) decreased rapidly, and so does the applied voltage. In addition, aeration could effectively enhance COD removal efficiency and protect anodes from corrosion. Furthermore, the acidic condition is beneficial to the rapid decrease of COD and the values of pH effluent are independent of the initial solution pH. The optimization conditions obtained from these experiments are applied voltage of 4.8 V, residence time of 180 min and air-liquid ratio of 4.2 with the COD effluent of about 690 mg L⁻¹. In these cases, the ACE and energy consumption are 388% and 4.144 kW h kg⁻¹ COD, respectively. These perfect results from the experiments illustrate that the combined process is a considerable alternative for the treatment of industrial wastewater containing high concentration of organic pollutants and salinity.

Improved removal performance and mechanism investigation of papermaking wastewater treatment using manganese enhanced Fenton reaction.

PubMed

Wang, Yingcai; Wang, Can; Shi, Shuai; Fang, Shuai

2018-06-01

The effects of Mn(II) on Fenton system to treat papermaking wastewater and the mechanism of Mn(II) enhanced Fenton reaction were investigated in this study. The chemical oxygen demand (COD) removal efficiency was enhanced in the presence of Mn(II), which increased by 19% compared with that of the Fenton system alone. The pseudo-first order reaction kinetic rate constant of Mn(II)/Fenton system was 2.11 times higher than that of Fenton system. 67%-81% COD were removed with the increasing Mn(II) concentration from 0 to 0.8 g/L. COD removal efficiency was also enhanced in a wider pH range (3-7), which indicated the operation parameters of Fenton technology could be broadened to a milder condition. The study of the mechanism showed that Mn(II) participated in the oxidation and coagulation stages in Fenton system. In the oxidation stage, Mn(II) promotes the production of HO 2 •/ O 2 • - , then HO 2 •/ O 2 • - reacts with Fe(III) to accelerate the formation of Fe(II), and finally accelerates the production of HO•. Meantime MnMnO 3 and Fe(OH) 3 forms in the coagulation stage, facilitating the removal of suspended substances and a large amount of COD, which enhances the overall COD removal of papermaking wastewater. This study provided a detailed mechanism to improve practical applications of Fenton technology.

Study on the effect of total dissolved solids (TDS) on the performance of an SBR for COD and nutrients removal.

PubMed

Wu, Sarah Xiao; Maskaly, Jason

2018-01-28

In this study, the effect of total dissolved solids (TDS) on the performance of a sequencing batch reactor (SBR) system to treat synthetic wastewater with microbial inoculum was evaluated. The SBR was operated continuously for eight days on a 6-h cycle with anaerobic/anoxic/aerobic phases in each cycle after entering the steady state, and the influent TDS was tested at five levels, i.e., 750, 1500, 3000, 4500, and 6000 mg L -1 . The results showed that only two TDS levels (750 and 1500 mg L -1 ) could achieve good COD removal efficiencies (94.8 and 92.2%, respectively). For TDS levels equal to, or greater than, 3000 mg L -1 , a 20% reduction in COD removal efficiency resulted. Different from COD, removal of NH 4 + -N appeared not to be affected by the TDS content, and a removal efficiency of higher than 97% was obtained, regardless of the TDS content. However, only the lowest two TDS levels achieved high phosphate removals (>99%), and the removal efficiency dropped to 57.8 and 45.9%, respectively, for TDS levels of 3000 and 4500 mg L -1 . More interestingly, a phosphate release, instead of uptake, was observed at the TDS level of 6000 mg L -1 . It may be concluded that for effective phosphate removal, the TDS level in the liquid should be controlled under 1500 mg L -1 , and higher liquid TDS levels were detrimental to the aerobes and could disrupt the aerobic metabolism, leading to the failure of the SBR treatment system. A tendency that raising TDS content would adversely affect the aerobic oxygen uptake rate was observed, which could also result in SBR upset. A power regression with an R of 0.9844 was established between the influent TDS concentration and the TDS removal efficiency, which may be used to estimate the SBR performance in TDS removal based on the influent TDS content.

Biological treatment of produced water in a sequencing batch reactor by a consortium of isolated halophilic microorganisms.

PubMed

Pendashteh, A R; Fakhru'l-Razi, A; Chuah, T G; Radiah, A B Dayang; Madaeni, S S; Zurina, Z A

2010-10-01

Produced water or oilfield wastewater is the largest volume ofa waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m(-3) d(-1), 1.8 kg COD m(-3) d(-1) and 3.6 kg COD m(-3) d(-1)) and different total dissolved solids (TDS) concentration (35,000 mg L(-1), 100,000 mg L(-1), 150,000 mg L(-1), 200,000 mg L(-1) and 250,000 mg L(-1)). It was found that with an OLR of 0.9 kg COD m(-3) d(-1) and 1.8 kg COD m(-3) d(-1), average oil and grease (O&G) concentrations in the effluent were 7 mg L(-1) and 12 mg L(-1), respectively. At TDS concentration of 35,000 mg L(-1) and at an OLR of 1.8 kg COD m(-3)d(-1), COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L(-1), COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83%, and 85%, respectively.

COD removal characteristics in air-cathode microbial fuel cells.

PubMed

Zhang, Xiaoyuan; He, Weihua; Ren, Lijiao; Stager, Jennifer; Evans, Patrick J; Logan, Bruce E

2015-01-01

Exoelectrogenic microorganisms in microbial fuel cells (MFCs) compete with other microorganisms for substrate. In order to understand how this affects removal rates, current generation, and coulombic efficiencies (CEs), substrate removal rates were compared in MFCs fed a single, readily biodegradable compound (acetate) or domestic wastewater (WW). Removal rates based on initial test conditions fit first-order kinetics, but rate constants varied with circuit resistance. With filtered WW (100Ω), the rate constant was 0.18h(-)(1), which was higher than acetate or filtered WW with an open circuit (0.10h(-)(1)), but CEs were much lower (15-24%) than acetate. With raw WW (100Ω), COD removal proceeded in two stages: a fast removal stage with high current production, followed by a slower removal with little current. While using MFCs increased COD removal rate due to current generation, secondary processes will be needed to reduce COD to levels suitable for discharge. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pollutant removal characteristics of a two-influent-line BNR process performing denitrifying phosphorus removal: role of sludge recycling ratios.

PubMed

Liu, Hongbo; Leng, Feng; Chen, Piao; Kueppers, Stephan

2016-11-01

This paper studied denitrifying phosphorus removal of a novel two-line biological nutrient removal process treating low strength domestic wastewater under different sludge recycling ratios. Mass balance of intracellular compounds including polyhydroxyvalerate, polyhydroxybutyrate and glycogen was investigated together with total nitrogen (TN) and total phosphorus (TP). Results showed that sludge recycling ratios had a significant influence on the use of organics along bioreactors and 73.6% of the average removal efficiency was obtained when the influent chemical oxygen demand (COD) ranged from 175.9 mgL -1 to 189.9 mgL -1 . The process performed better under a sludge recycling ratio of 100% compared to 25% and 50% in terms of ammonia and COD removal rates. Overall, TN removal efficiency for 50% and 100% sludge recycling ratios were 56.4% and 61.9%, respectively, unlike the big gap for carbon utilization and the TP removal rates, indicating that the effect of sludge recycling ratio on the anaerobic compartments had been counteracted by change in the efficiency of other compartments. The higher ratio of sludge recycling was conducive to the removal of TN, not in favor of TP, and less influence on COD. Thus, 25% was considered to be the optimal sludge recycling ratio.

Effect of time on dyeing wastewater treatment

NASA Astrophysics Data System (ADS)

Ye, Tingjin; Chen, Xin; Xu, Zizhen; Chen, Xiaogang; Shi, Liang; He, Lingfeng; Zhang, Yongli

2018-03-01

The preparation of carboxymethylchitosan wrapping fly-ash adsorbent using high temperature activated fly ash and sodium carboxymethyl chitosan (CWF), as with the iron-carbon micro-electrolysis process simulation and actual printing and dyeing wastewater. The effects of mixing time and static time on decolorization ratio, COD removing rate and turbidness removing rate were investigated. The experimental results show that the wastewater stirring times on the decolorization rate and COD removal rate and turbidity removal rate influence, with increasing of the stirring time, three showed a downward trend, and reached the peak at 10 min time; wastewater time on the decolorization ratio and COD removing efficiency and turbidness removing rate influence, along with standing time increase, three who declined and reached the maximum in 30min time.

Application of Box-Wilson experimental design method for 2,4-dinitrotoluene treatment in a sequential anaerobic migrating blanket reactor (AMBR)/aerobic completely stirred tank reactor (CSTR) system.

PubMed

Kuşçu, Özlem Selçuk; Sponza, Delia Teresa

2011-03-15

A sequential aerobic completely stirred tank reactor (CSTR) following the anaerobic migrating blanket reactor (AMBR) was used to treat a synthetic wastewater containing 2,4-dinitrotoluene (2,4-DNT). A Box-Wilson statistical experiment design was used to determine the effects of 2,4-DNT and the hydraulic retention times (HRTs) on 2,4-DNT and COD removal efficiencies in the AMBR reactor. The 2,4-DNT concentrations in the feed (0-280 mg/L) and the HRT (0.5-10 days) were considered as the independent variables while the 2,4-DNT and chemical oxygen demand (COD) removal efficiencies, total and methane gas productions, methane gas percentage, pH, total volatile fatty acid (TVFA) and total volatile fatty acid/bicarbonate alkalinity (TVFA/Bic.Alk.) ratio were considered as the objective functions in the Box-Wilson statistical experiment design in the AMBR. The predicted data for the parameters given above were determined from the response functions by regression analysis of the experimental data and exhibited excellent agreement with the experimental results. The optimum HRT which gave the maximum COD (97.00%) and 2,4-DNT removal (99.90%) efficiencies was between 5 and 10 days at influent 2,4-DNT concentrations 1-280 mg/L in the AMBR. The aerobic CSTR was used for removals of residual COD remaining from the AMBR, and for metabolites of 2,4-DNT. The maximum COD removal efficiency was 99% at an HRT of 1.89 days at a 2,4-DNT concentration of 239 mg/L in the aerobic CSTR. It was found that 280 mg/L 2,4-DNT transformed to 2,4-diaminotoluene (2,4-DAT) via 2-amino-4-nitrotoluene (2-A-4-NT) and 4-amino-2-nitrotoluene (4-A-2-NT) in the AMBR. The maximum 2,4-DAT removal was 82% at an HRT of 8.61 days in the aerobic CSTR. The maximum total COD and 2,4-DNT removal efficiencies were 99.00% and 99.99%, respectively, at an influent 2,4-DNT concentration of 239 mg/L and at 1.89 days of HRT in the sequential AMBR/CSTR. Copyright © 2011 Elsevier B.V. All rights reserved.

Optimization of rotational speed and hydraulic retention time of a rotational sponge reactor for sewage treatment.

PubMed

Hewawasam, Choolaka; Matsuura, Norihisa; Takimoto, Yuya; Hatamoto, Masashi; Yamaguchi, Takashi

2018-05-26

A rotational sponge (RS) reactor was proposed as an alternative sewage treatment process. Prior to the application of an RS reactor for sewage treatment, this study evaluated reactor performance with regard to organic removal, nitrification, and nitrogen removal and sought to optimize the rotational speed and hydraulic retention time (HRT) of the system. RS reactor obtained highest COD removal, nitrification, and nitrogen removal efficiencies of 91%, 97%, and 65%, respectively. For the optimization, response surface methodology (RSM) was employed and optimum conditions of rotational speed and HRT were 18 rounds per hour and 4.8 h, respectively. COD removal, nitrification, and nitrogen removal efficiencies at the optimum conditions were 85%, 85%, and 65%, respectively. Corresponding removal rates at optimum conditions were 1.6 kg-COD m -3 d -1 , 0.3 kg-NH 4 + -N m -3 d -1 , and 0.12 kg-N m -3 d -1 . Microbial community analysis revealed an abundance of nitrifying and denitrifying bacteria in the reactor, which contributed to nitrification and nitrogen removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Performance of Grass Swales for Controlling Pollution of Roadway Runoff in Field Experiments].

PubMed

Huang, Jun-jie; Shen, Qing-ran; Li, Tian

2015-06-01

Two different styles of grass swales were built in new Binhu region of Hefei city to monitor the flux and quality of the influent and effluent water under actual precipitation conditions, in order to evaluate the performance of water quality purification and pollution load control for roadway runoff. The results showed that both of the grass swales could effectively remove the pollutants such as TSS, COD, Pb, Cu, Cd, Zn in roadway runoff; the median EMC removal efficiencies of TSS and COD were 67.1%, 46.7% respectively,for facility I, and the median EMC removal efficiencies of TSS and COD were 78.6%, 58.6% respectively, for facility II; the concentrations of Pb, Cu, Zn in the effluent of facility II could meet the requirements of the surface water quality class V; release of nitrogen and phosphorus occurred in both facilities I and I[ in several rainfall events, mainly in heavy storms; the removal efficiencies of TP in the two grass swales were improved with the increase of influent concentration; the mean removal efficiencies of TP in facilities I and II were 14.7% and 45.4%, respectively; the load control performance of facility II for pollutants such as TSS, COD, TP, TN, NH4+ -N and NO3- -N was better than that of facility I; in the district with poor soil permeability and low ground slope, application of dry swale could achieve better performance in water quality control and pollution load reduction of roadway runoff.

Treatment of industrial estate wastewater by the application of electrocoagulation process using iron electrodes.

PubMed

Yavuz, Y; Ögütveren, Ü B

2018-02-01

In this study electrocoagulation (EC) of industrial estate wastewater taken from the inlet of wastewater treatment plant was investigated using sacrificial iron electrodes. Employing a pole changer to homogenous consumption of electrodes, studies on the parameters such as current density, supporting electrolyte concentration and initial pH, which have significant effects on COD removal and hence the energy consumption, were performed. Hydrogen peroxide was used in different concentrations to observe its effects on COD removal efficiency and the energy consumption. Sludge productions were also calculated for all experiments. COD removal efficiency of ∼92% was obtained at the best experimental conditions (i = 30 mA/cm 2 , SE = 3 mM Na 2 SO 4 , pH = original pH (∼6) of the wastewater, 1500 mg/L H 2 O 2 ) with an energy cost of €3.41/m 3 wastewater treated and the sludge production of 5.45 g per g COD removed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of powdered activated carbon technology on short-cut nitrogen removal for coal gasification wastewater.

PubMed

Zhao, Qian; Han, Hongjun; Xu, Chunyan; Zhuang, Haifeng; Fang, Fang; Zhang, Linghan

2013-08-01

A combined process consisting of a powdered activated carbon technology (PACT) and short-cut biological nitrogen removal reactor (SBNR) was developed to enhance the removal efficiency of the total nitrogen (TN) from the effluent of an upflow anaerobic sludge bed (UASB) reactor, which was used to treat coal gasification wastewater (CGW). The SBNR performance was improved with the increasing of COD and TP removal efficiency via PACT. The average removal efficiencies of COD and TP in PACT were respectively 85.80% and 90.30%. Meanwhile, the NH3-N to NO2-N conversion rate was achieved 86.89% in SBNR and the total nitrogen (TN) removal efficiency was 75.54%. In contrast, the AOB in SBNR was significantly inhibited without PACT or with poor performance of PACT in advance, which rendered the removal of TN. Furthermore, PAC was demonstrated to remove some refractory compounds, which therefore improved the biodegradability of the coal gasification wastewater. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Advanced purification of petroleum refinery wastewater by catalytic vacuum distillation.

PubMed

Yan, Long; Ma, Hongzhu; Wang, Bo; Mao, Wei; Chen, Yashao

2010-06-15

In our work, a new process, catalytic vacuum distillation (CVD) was utilized for purification of petroleum refinery wastewater that was characteristic of high chemical oxygen demand (COD) and salinity. Moreover, various common promoters, like FeCl(3), kaolin, H(2)SO(4) and NaOH were investigated to improve the purification efficiency of CVD. Here, the purification efficiency was estimated by COD testing, electrolytic conductivity, UV-vis spectrum, gas chromatography-mass spectrometry (GC-MS) and pH value. The results showed that NaOH promoted CVD displayed higher efficiency in purification of refinery wastewater than other systems, where the pellucid effluents with low salinity and high COD removal efficiency (99%) were obtained after treatment, and the corresponding pH values of effluents varied from 7 to 9. Furthermore, environment estimation was also tested and the results showed that the effluent had no influence on plant growth. Thus, based on satisfied removal efficiency of COD and salinity achieved simultaneously, NaOH promoted CVD process is an effective approach to purify petroleum refinery wastewater. Copyright 2010 Elsevier B.V. All rights reserved.

Transformation characteristics of refractory pollutants in plugboard wastewater by an optimal electrocoagulation and electro-Fenton process.

PubMed

Zhao, Xu; Zhang, Baofeng; Liu, Huijuan; Chen, Fayuan; Li, Angzhen; Qu, Jiuhui

2012-05-01

The treatment of the plugboard wastewater was performed by an optimal electrocoagulation and electro-Fenton. The organic components with suspended fractions accounting for 30% COD were preferably removed via electrocoagulation at initial 5 min. In contrast, the removal efficiency was increased to 76% with the addition of H(2)O(2). The electrogenerated Fe(2+) reacts with H(2)O(2) and leads to the generation of (·)OH, which is responsible for the higher COD removal. However, overdosage H(2)O(2) will consume (·)OH generated in the electro-Fenton process and lead to the low COD removal. The COD removal efficiency decreased with the increased pH. The concentration of Fe(2+) ions was dependent on the solution pH, H(2)O(2) dosage and current density. The changes of organic characteristics in coagulation and oxidation process were differenced and evaluated using gel permeation chromatography, fluorescence excitation-emission scans and Fourier transform infrared spectroscopy. The fraction of the wastewater with aromatic structure and large molecular weight was decomposed into aliphatic structure and small molecular weight fraction in the electro-Fenton process. Copyright © 2012. Published by Elsevier Ltd.

Submerged anaerobic membrane bioreactor (SAnMBR) performance on sewage treatment: removal efficiencies, biogas production and membrane fouling.

PubMed

Chen, Rong; Nie, Yulun; Ji, Jiayuan; Utashiro, Tetsuya; Li, Qian; Komori, Daisuke; Li, Yu-You

2017-09-01

A submerged anaerobic membrane reactor (SAnMBR) was employed for comprehensive evaluation of sewage treatment at 25 °C and its performance in removal efficiency, biogas production and membrane fouling. Average 89% methanogenic degradation efficiency as well as 90%, 94% and 96% removal of total chemical oxygen demand (TCOD), biochemical oxygen demand (BOD) and nonionic surfactant were obtained, while nitrogen and phosphorus were only subjected to small removals. Results suggest that SAnMBRs can effectively decouple organic degradation and nutrients disposal, and reserve all the nitrogen and phosphorus in the effluent for further possible recovery. Small biomass yields of 0.11 g mixed liquor volatile suspended solids (MLVSS)/gCOD were achieved, coupled to excellent methane production efficiencies of 0.338 NLCH 4 /gCOD, making SAnMBR an attractive technology characterized by low excess sludge production and high bioenergy recovery. Batch tests revealed the SAnMBR appeared to have the potential to bear a high food-to-microorganism ratio (F/M) of 1.54 gCOD/gMLVSS without any inhibition effect, and maximum methane production rate occurred at F/M 0.7 gCOD/gMLVSS. Pore blocking dominated the membrane fouling behaviour at a relative long hydraulic retention time (HRT), i.e. >12 hours, while cake layer dominated significantly at shorter HRTs, i.e. <8 hours.

Preliminary screening oxidative degradation methyl orange using ozone/ persulfate

NASA Astrophysics Data System (ADS)

Aqilah Razali, Nur; Zulzikrami Azner Abidin, Che; An, Ong Soon; Ridwan, Fahmi Muhammad; Haqi Ibrahim, Abdul; Nasuha Sabri, Siti; Huan Kow, Su

2018-03-01

The present study focusing on the performances of advanced oxidation process by using ozonation method towards Methyl Orange based on the efficiency of colour removal and Chemical Oxygen Demand (COD) removal. Factorial design with response surface methodology (RSM) was used to evaluate the interaction between operational conditions, such as pH, initial concentration, contact time and persulfate dosage to obtain the optimum range conditions using a semi-batch reactor. The range of independent variables investigated were pH (3-11), initial concentration (100-500mg/L), contact time (10-50min) and persulfate dosage (20-100mM) while the response variables were colour removal and COD removal of Methyl Orange. The experimental results and statistical analysis showed all the parameters were significant. Thus, from this findings, optimization of operational conditions that had been suggested from the ozone/persulfate RSM analysis were (pH 3, 100 mg/L, 50min, 60mM) that would be produced 99% Colour Removal and 80% COD Removal and help in promoting an efficient ozonation process. The effect list data that showed the most contributed effects to increase the percentages of colour removal were pH and persulfate dosage whereas the contact time and initial concentration had the highest positive effects on the COD removal. Other than that, the interaction between pH, contact time and persulfate dosage were found to be the most influencing interaction. Therefore the least influencing interaction was interaction between persulfate dosage and pH. In this study, the correlation coefficient value R2 for colour removal and COD removal of Methyl Orange were R2= 0.9976 and R2= 0.9924 which suggested a good fit of the first-order regression model with the experimental data.

Effect of feed characteristics on the organic matter, nitrogen and phosphorus removal in an activated sludge system treating piggery slurry.

PubMed

González, C; García, P A; Muñoz, R

2009-01-01

Piggery wastewater is characterized by its high content in nitrogen and phosphorus, as well as by a low C/N ratio. This type of wastewater is traditionally spread to croplands (with its subsequent leaching to groundwater) or rarely discharged into natural water bodies, which ultimately cause severe episodes of eutrophication in aquatic ecosystems. In this context, activated sludge systems constitute a robust and efficient treatment option. The performance of an activated sludge process using a pre-denitrification configuration treating both sieved and flocculated swine slurry at a hydraulic retention time (HRT) of 7.7 days was evaluated. In order to avoid bacterial wash-out, sludge from the settler was recirculated to the anoxic tank to accomplish denitrification. Once the biomass was acclimatized, the reactor was fed with swine slurry containing 19, 2.6, and 0.27 g/L of total chemical oxygen demand (COD), total Kjeldhal nitrogen (TKN), and soluble P, respectively. Nitrogen removal showed a clear dependency on the influent composition. When the influent TKN/total COD and soluble COD/total COD ratios were respectively 0.12-0.15 and 0.7, the reactor exhibited good removal efficiencies (up to 99 and 91 for N-NH(4)(+), TKN, respectively) while PO(4)(3-) was removed up to 65%. However, when the influent TKN/total COD ratio rose to 0.26 and soluble COD/total COD decreased to 0.3, the denitrification process was severely hindered concomitant with and accumulation of nitrite. Nevertheless, organic matter degradation was not affected by influent composition. At the last stage of the experiment, removals of dissolved phosphorus fell to 40% when the redox potential (ORP) profile showed a constant value of -400 mV, likely due to phosphate released from bacterial sludge.

Textile wastewater treatment: colour and COD removal of reactive black-5 by ozonation

NASA Astrophysics Data System (ADS)

Suryawan, I. W. K.; Helmy, Q.; Notodarmojo, S.

2018-01-01

Textile industries produced a large amount of highly coloured wastewater containing variety of dyes in different concentrations. Due to the high concentration of organics in the effluents and the higher stability of modern synthetic dyes, the conventional biological treatment methods are ineffective for the complete colour removal and degradation of organics and dyes. On the other hand, physical-chemical treatment are not destructive, mainly just concentrate and separate the pollutants phases. This research paper investigates the removal of colour and chemical oxygen demand/COD from textile wastewater using ozone treatment. Varied ozone dosages of 1.16; 3.81; 18.79; and 40.88 mg/minute were used in the experiment. Varied wastewater containing Reactive Black 5 (RB-5) concentrations of 40 mg/L, 100 mg/L were also applied. Research result showed the highest colour removal efficiency of 96.9 % was achieved after 5 hours incubation time, while the highest COD removal efficiency of 77.5% was achieved after 2 hours incubation time.

Dual purpose recovered coagulant from drinking water treatment residuals for adjustment of initial pH and coagulation aid in electrocoagulation process.

PubMed

Jung, Kyung-Won; Ahn, Kyu-Hong

2016-01-01

The present study is focused on the application of recovered coagulant (RC) by acidification from drinking water treatment residuals for both adjusting the initial pH and aiding coagulant in electrocoagulation. To do this, real cotton textile wastewater was used as a target pollutant, and decolorization and chemical oxygen demand (COD) removal efficiency were monitored. A preliminary test indicated that a stainless steel electrode combined with RC significantly accelerated decolorization and COD removal efficiencies, by about 52% and 56%, respectively, even at an operating time of 5 min. A single electrocoagulation system meanwhile requires at least 40 min to attain the similar removal performances. Subsequently, the interactive effect of three independent variables (applied voltage, initial pH, and reaction time) on the response variables (decolorization and COD removal) was evaluated, and these parameters were statistically optimized using the response surface methodology. Analysis of variance showed a high coefficient of determination values (decolorization, R(2) = 0.9925 and COD removal, R(2) = 0.9973) and satisfactory prediction second-order polynomial quadratic regression models. Average decolorization and COD removal of 89.52% and 94.14%, respectively, were achieved, corresponding to 97.8% and 98.1% of the predicted values under statistically optimized conditions. The results suggest that the RC effectively played a dual role of both adjusting the initial pH and aiding coagulant in the electrocoagulation process.

Municipal waste liquor treatment via bioelectrochemical and fermentation (H2 + CH4) processes: Assessment of various technological sequences.

PubMed

Rózsenberszki, Tamás; Koók, László; Bakonyi, Péter; Nemestóthy, Nándor; Logroño, Washington; Pérez, Mario; Urquizo, Gladys; Recalde, Celso; Kurdi, Róbert; Sarkady, Attila

2017-03-01

In this paper, the anaerobic treatment of a high organic-strength wastewater-type feedstock, referred as the liquid fraction of pressed municipal solid waste (LPW) was studied for energy recovery and organic matter removal. The processes investigated were (i) dark fermentation to produce biohydrogen, (ii) anaerobic digestion for biogas formation and (iii) microbial fuel cells for electrical energy generation. To find a feasible alternative for LPW treatment (meeting the two-fold aims given above), various one- as well as multi-stage processes were tested. The applications were evaluated based on their (i) COD removal efficiencies and (ii) specific energy gain. As a result, considering the former aspect, the single-stage processes could be ranked as: microbial fuel cell (92.4%)> anaerobic digestion (50.2%)> hydrogen fermentation (8.8%). From the latter standpoint, an order of hydrogen fermentation (2277 J g -1  COD removed  d -1 )> anaerobic digestion (205 J g -1  COD removed  d -1 )> microbial fuel cell (0.43 J g -1  COD removed  d -1 ) was attained. The assessment showed that combined, multi-step treatment was necessary to simultaneously achieve efficient organic matter removal and energy recovery from LPW. Therefore, a three-stage system (hydrogen fermentation-biomethanation-bioelectrochemical cell in sequence) was suggested. The different approaches were characterized via the estimation of COD balance, as well. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation of Anaerobic Fluidized Bed Reactor/ Aerobic Moving Bed Bio Reactor (AFBR/MMBR) System for Treatment of Currant Wastewater

PubMed Central

JAFARI, Jalil; MESDAGHINIA, Alireza; NABIZADEH, Ramin; FARROKHI, Mehrdad; MAHVI, Amir Hossein

2013-01-01

Background: Anaerobic treatment methods are more suitable for the treatment of concentrated wastewater streams, offer lower operating costs, the production of usable biogas product. The aim of this study was to investigate the performance of an Anaerobic Fluidized Bed Reactor (AFBR)-Aerobic Moving Bed Bio Reactor (MBBR) in series arrangement to treat Currant wastewater. Methods: The bed materials of AFBR were cylindrical particles made of PVC with a diameter of 2–2.3 mm, particle density of 1250 kg/m3. The volume of all bed materials was 1.7 liter which expanded to 2.46 liters in fluidized situation. In MBBR, support media was composed of 1.5 liters Bee-Cell 2000 having porosity of 87% and specific surface area of 650m2/m3. Results: When system operated at 35 ºC, chemical oxygen demand (COD) removal efficiencies were achieved to 98% and 81.6% for organic loading rates (OLR) of 9.4 and 24.2 g COD/l.d, and hydraulic retention times (HRT) of 48 and 18 h, in average COD concentration feeding of 18.4 g/l, respectively. Conclusion: The contribution of AFBR in total COD removal efficiency at an organic loading rate (OLR) of 9.4 g COD/l.d was 95%, and gradually decreased to 76.5% in OLR of 24.2 g COD/l.d. Also with increasing in organic loading rate the contribution of aerobic reactor in removing COD gradually decreased. In this system, the anaerobic reactor played the most important role in the removal of COD, and the aerobic MBBR was actually needed to polish the anaerobic treated wastewater. PMID:26056640

Potential for enhancement of aerobic biological removal of recalcitrant organic matter in bleached pulp mill effluents.

PubMed

Mounteer, A H; Souza, L C; Silva, C M

2007-02-01

Increasingly stringent effluent quality limits for bleached kraft pulp mills pose a great challenge to mill wastewater system managers since these limits can require levels of chemical oxygen demand (COD) removal efficiency rarely reported for biological treatment of these types of effluents. The present study was therefore undertaken to better understand the nature of recalcitrant COD in bleached kraft pulp effluents that persists through the biological treatment system. Bleaching effluents from a Brazilian eucalypt bleached kraft pulp mill were collected and treated in a bench-scale sequencing batch reactor. Organic matter in raw and treated effluents was characterized before and after separation into low and high molecular mass fractions. Biological treatment removed 71% of the COD, with 83% removal of the low molecular mass COD but only 36% removal of the high molecular mass COD. Microorganisms capable of degrading the recalcitrant COD were isolated from enrichment cultures of the original activated sludge fed on fractions of the bleaching effluent that presented low biodegradabilities. Use of a microbial consortium composed of ten of these isolates to treat the biologically treated effluent removed a further 12% of the effluent COD, all from the high molecular mass fraction. Results of this research indicate that microorganisms with potential for degrading recalcitrant COD are present in activated sludge, but that these are not metabolically active during normal activated sludge treatment of mill effluents. The use of biological selectors in the treatment system to promote growth of such microorganisms may enhance removal of recalcitrant organic matter.

Continuous electrocoagulation of cheese whey wastewater: an application of Response Surface Methodology.

PubMed

Tezcan Un, Umran; Kandemir, Ayse; Erginel, Nihal; Ocal, S Eren

2014-12-15

In this study, treatment of cheese whey wastewater was performed using a uniquely-designed continuous electrocoagulation reactor, not previously encountered in the literature. An iron horizontal rotating screw type anode was used in the continuous mode. An empirical model, in terms of effective operational factors, such as current density (40, 50, 60 mA/cm(2)), pH (3, 5, 7) and retention time (20, 40, 60 min), was developed through Response Surface Methodology. An optimal region characterized by low values of Chemical Oxygen Demand (COD) was determined. As a result of experiments, a linear effect in the removal efficiency of COD was obtained for current density and retention time, while the initial pH of the wastewater was found to have a quadratic effect in the removal efficiency of COD. The best fit nonlinear mathematical model, with a coefficient of determination value (R(2)) of 85%, was defined. An initial COD concentration of 15.500 mg/L was reduced to 2112 mg/L with a removal efficiency of 86.4%. In conclusion, it can be said that electrocoagulation was successfully applied for the treatment of cheese whey wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical Oxygen Demand abatement in sewage using Micro-Aeration Enhanced Ecological Floating Bed

NASA Astrophysics Data System (ADS)

Shi, Hongle; Zhou, Gaofeng; Liu, Yiqing; Tan, Jiancong; Fu, Yongsheng

2018-02-01

The traditional ecological floating bed combined with micro-aeration system and artificial medium was developed for the removal of contaminants and remediation of surface water. This micro-aeration enhanced ecological floating bed (MAEEFB) consisted of aeration unit, microbial processing unit and aquatic plant unit. Batch experiments were conducted in different operating conditions on the removal of chemical oxygen demand (COD) in the sewage using MAEEFB. The removal rate of COD by MAEEFB, enhanced ecological floating bed (EEFB) and traditional ecological floating bed (TEFB) in the same reaction conditions was 59.2%, 56.9% and 30.6%, respectively, indicating that the combination of micro-aeration system and artificial medium could enhance the removal efficiency of COD in TEFB. In MAEEFB, the aeration intensity should be designed reasonablely considering both treatment efficiency and operation cost. Only increasing the specific surface area of the packing cannot effectively improve the purification efficiency of water. Factors like packing material, ability of intercepting organics and complicated extent of microorganisms attaching on the packing should also be considered.

Advanced treatment of biologically pretreated coal chemical industry wastewater using the catalytic ozonation process combined with a gas-liquid-solid internal circulating fluidized bed reactor.

PubMed

Li, Zhipeng; Liu, Feng; You, Hong; Ding, Yi; Yao, Jie; Jin, Chao

2018-04-01

This paper investigated the performance of the combined system of catalytic ozonation and the gas-liquid-solid internal circulating fluidized bed reactor for the advanced treatment of biologically pretreated coal chemical industry wastewater (CCIW). The results indicated that with ozonation alone for 60min, the removal efficiency of chemical oxygen demand (COD) could reach 34%. The introduction of activated carbon, pumice, γ-Al 2 O 3 carriers improved the removal performance of COD, and the removal efficiency was increased by 8.6%, 4.2%, 2%, respectively. Supported with Mn, the catalytic performance of activated carbon and γ-Al 2 O 3 were improved significantly with COD removal efficiencies of 46.5% and 41.3%, respectively; however, the promotion effect of pumice supported with Mn was insignificant. Activated carbon supported with Mn had the best catalytic performance. The catalytic ozonation combined system of MnO X /activated carbon could keep ozone concentration at a lower level in the liquid phase, and promote the transfer of ozone from the gas phase to the liquid phase to improve ozonation efficiency.

Cultivation of Chlorella vulgaris JSC-6 with swine wastewater for simultaneous nutrient/COD removal and carbohydrate production.

PubMed

Wang, Yue; Guo, Wanqian; Yen, Hong-Wei; Ho, Shih-Hsin; Lo, Yung-Chung; Cheng, Chieh-Lun; Ren, Nanqi; Chang, Jo-Shu

2015-12-01

Swine wastewater, containing a high concentration of COD and ammonia nitrogen, is suitable for the growth of microalgae, leading to simultaneous COD/nutrients removal from the wastewater. In this study, an isolated carbohydrate-rich microalga Chlorella vulgaris JSC-6 was adopted to perform swine wastewater treatment. Nearly 60-70% COD removal and 40-90% NH3-N removal was achieved in the mixotrophic and heterotrophic culture, depending on the dilution ratio of the wastewater, while the highest removal percentage was obtained with 20-fold diluted wastewater. Mixotrophic cultivation by using fivefold diluted wastewater resulted in the highest biomass concentration of 3.96 g/L. The carbohydrate content of the microalga grown on the wastewater can reach up to 58% (per dry weight). The results indicated that the microalgae-based wastewater treatment can efficiently reduce the nutrients and COD level, and the resulting microalgal biomass had high carbohydrate content, thereby having potential applications for the fermentative production of biofuels or chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Performance of anaerobic fluidized membrane bioreactors using effluents of microbial fuel cells treating domestic wastewater.

PubMed

Kim, Kyoung-Yeol; Yang, Wulin; Ye, Yaoli; LaBarge, Nicole; Logan, Bruce E

2016-05-01

Anaerobic fluidized membrane bioreactors (AFMBRs) have been mainly developed as a post-treatment process to produce high quality effluent with very low energy consumption. The performance of an AFMBR was examined using the effluent from a microbial fuel cell (MFC) treating domestic wastewater, as a function of AFMBR hydraulic retention times (HRTs) and organic matter loading rates. The MFC-AFMBR achieved 89 ± 3% removal of the chemical oxygen demand (COD), with an effluent of 36 ± 6 mg-COD/L over 112 days operation. The AFMBR had very stable operation, with no significant changes in COD removal efficiencies, for HRTs ranging from 1.2 to 3.8h, although the effluent COD concentration increased with organic loading. Transmembrane pressure (TMP) was low, and could be maintained below 0.12 bar through solids removal. This study proved that the AFMBR could be operated with a short HRT but a low COD loading rate was required to achieve low effluent COD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anodic oxidation of coke oven wastewater: Multiparameter optimization for simultaneous removal of cyanide, COD and phenol.

PubMed

Sasidharan Pillai, Indu M; Gupta, Ashok K

2016-07-01

Anodic oxidation of industrial wastewater from a coke oven plant having cyanide including thiocyanate (280 mg L(-1)), chemical oxygen demand (COD - 1520 mg L(-1)) and phenol (900 mg L(-1)) was carried out using a novel PbO2 anode. From univariate optimization study, low NaCl concentration, acidic pH, high current density and temperature were found beneficial for the oxidation. Multivariate optimization was performed with cyanide including thiocyanate, COD and phenol removal efficiencies as a function of changes in initial pH, NaCl concentration and current density using Box-Behnken experimental design. Optimization was performed for maximizing the removal efficiencies of these three parameters simultaneously. The optimum condition was obtained as initial pH 3.95, NaCl as 1 g L(-1) and current density of 6.7 mA cm(-2), for which the predicted removal efficiencies were 99.6%, 86.7% and 99.7% for cyanide including thiocyanate, COD and phenol respectively. It was in agreement with the values obtained experimentally as 99.1%, 85.2% and 99.7% respectively for these parameters. The optimum conditions with initial pH constrained to a range of 6-8 was initial pH 6, NaCl as 1.31 g L(-1) and current density as 6.7 mA cm(-2). The predicted removal efficiencies were 99%, 86.7% and 99.6% for the three parameters. The efficiencies obtained experimentally were in agreement at 99%, 87.8% and 99.6% respectively. The cost of operation for degradation at optimum conditions was calculated as 21.4 USD m(-3). Copyright © 2016 Elsevier Ltd. All rights reserved.

Community onsite treatment of cold strong sewage in a UASB-septic tank.

PubMed

Al-Jamal, Wafa; Mahmoud, Nidal

2009-02-01

Two community onsite UASB-septic tanks namely R1 and R2 were operated under two different HRT (2 days for R1 and 4 days for R2) in parallel over a year and monitored over the cold half of the year. During the monitoring period, the sewage was characterised by a high COD(tot) of 905mg/l with a high fraction of COD(ss), viz. about 43.7%, and rather low temperature of 17.3 degrees C. The achieved removal efficiencies in R1 and R2 for COD(tot), COD(sus), COD(col), COD(dis), BOD(5) and TSS were "51%, 83%, 20%, 24%, 45% and 74%" and "54%, 87%, 10%, 28%, 49% and 78%", respectively. The difference in the removal efficiencies of those parameters in R1 and R2 is marginal and was only significant (p<0.05) for COD(sus). The sludge filling period of the reactors is expected to be 4-7 years. In view of that, the UASB-septic tank system is a robust and compact system as it can be adequately designed in Palestine at 2 days HRT.

Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors

PubMed Central

Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

2014-01-01

This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m−3·d−1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

Composite wastewater treatment by aerated electrocoagulation and modified peroxi-coagulation processes.

PubMed

Kumar, Abhijeet; Nidheesh, P V; Suresh Kumar, M

2018-08-01

Treatment of composite wastewater generating from the industrial estates is a great challenge. The present study examines the applicability of aerated electrocoagulation and modified peroxi-coagulation processes for removing color and COD from composite wastewater. Iron plates were used as anodes and cathodes in both electrochemical processes and experiments were carried out in a working volume of 2 L. Aeration enhanced the efficiency of electrocoagulation process significantly. More than 50% of COD and 60% of color were removed after 1 h of electrocoagulation process operated at pH 3 and applied voltage of 1 V. Efficiency of the modified peroxi-coagulation process was significantly higher than that of aerated electrocoagulation. COD and color removal efficiencies of the modified peroxi-coagulation process were found as 77.7% and 97%, respectively after 1 h of electrolysis operated at 1 V, solution pH 3 and 50 mM hydrogen peroxide addition. This improved efficiency of modified peroxi-coagulation compared to aerated electrocoagulation is mainly due to the attack of in-situ generated hydroxyl radicals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Grey water treatment by the slanted soil system with unsorted soil media.

PubMed

Ushijima, Ken; Tanaka, Erina; Suzuki, Laís Yuko; Hijikata, Nowaki; Funamizu, Naoyuki; Ito, Ryusei

2015-01-01

This study evaluated the performance of unsorted soil media in the slanted soil treatment system, in terms of removal efficiency in suspended solids (SS), chemical oxygen demand (COD), linear alkylbenzene sulphonate (LAS) and Escherichia coli, and lifetime until clogging occurs. Unsorted soil performed longer lifetime until clogging than sorted fine soil. Removal of SS, COD, and LAS also performed same or better level in unsorted soil than fine soil. As reaction coefficients of COD and LAS were described as a function of the hydraulic loading rate, we can design a slanted soil system according to the expected hydraulic loading rate and the targeted level of COD or LAS in effluent. Regarding bacteria removal, unsorted soil performed sufficient reduction of E. coli for 5 weeks; however, the removal process occurred throughout all four chambers, while that of fine soil occurred in one to two chambers.

Reuse the pulp and paper industry wastewater by using fashionable technology

NASA Astrophysics Data System (ADS)

Sudarshan, K.; Maruthaiya, K.; Kotteeswaran, P.; Murugan, A.

2017-10-01

This proposed method is a promising way, which can be implemented in pulp and paper industries by effective removal of the color and chemical oxygen demand (COD) and the resulting treated water may surely reuse to the other streams. Fourier Transformer Infra Red spectra confirmed the presence of the respective functional groups in the removed pollutants from the wastewater. The efficiency of Non-ferric Alum (NF Alum) and cationic polyacrylamide (C-PAM) with and without power boiler fly ash was also studied. The reduction efficiency of color and chemical oxygen demand (COD) is evaluated at the optimum dosage of NF Alum, fly ash, and C-PAM. At the optimized pH attained from these coagulants using to treat the wastewater, the flocs formation/settling and the pollutant removal efficiency are encouraging and the resulting color of the wastewater is to 40 PtCo units from 330 PtCo units and COD to 66 mg/L from 218 mg/L. While using NF Alum alone with C-PAM for the treatment of wastewater, the highest reduction efficiency of COD is 97 mg/L from 218 mg/L and the color is 60 from 330 PtCo units at pH 4.8 was noted. From these observations, NF Alum and power boiler fly ash with C-PAM can effectively remove the pollutants from the pulp and paper mill wastewater and the water can be reused for other streams.

Organic pollutants removal from 2,4,6-trinitrotoluene (TNT) red water using low cost activated coke.

PubMed

Zhang, Mohe; Zhao, Quanlin; Ye, Zhengfang

2011-01-01

We treated 2,4,6-trinitrotoluene (TNT) red water from the Chinese explosive industry with activated coke (AC) from lignite. Since the composition of TNT red water was very complicated, chemical oxygen demand (COD) was used as the index for evaluating treatment efficiency. This study focused on sorption kinetics and equilibrium sorption isotherms of AC for the removal of COD from TNT red water, and the changes of water quality before and after adsorption were evaluated using high performance liquid chromatography, UV-Vis spectra and gas chromatography/mass spectroscopy. The results showed that the sorption kinetics of COD removal from TNT red water onto AC fitted well with the pseudo second-order model. The adsorption process was an exothermic and physical process. The sorption isotherm was in good agreement with Redlich-Peterson isotherm. At the conditions of initial pH = 6.28, 20 degrees C and 3 hr of agitation, under 160 g/L AC, 64.8% of COD was removed. The removal efficiencies of 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO3-) and 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO3-) were 80.5% and 84.3%, respectively. After adsorption, the acute toxicity of TNT red water reduced greatly, compared with that of unprocessed TNT red water.

Removal of refractory contaminants in municipal landfill leachate by hydrogen, oxygen and palladium: a novel approach of hydroxyl radical production.

PubMed

Yu, Yingjian; Chen, Zhulei; Guo, Zhiyuan; Liao, Zhuwei; Yang, Lie; Wang, Jia; Chen, Zhuqi

2015-04-28

Municipal solid waste (MSW) leachate contains various refractory pollutants that pose potential threats to both surface water and groundwater. This paper established a novel catalytic oxidation process for leachate treatment, in which OH is generated in situ by pumping both H2 and O2 in the presence of Pd catalyst and Fe(2+). Volatile fatty acids in the leachate were removed almost completely by aeration and/or mechanical mixing. In this approach, a maximum COD removal of 56.7% can be achieved after 4h when 200mg/L Fe(2+) and 1250mg/L Pd/Al2O3 (pH 3.0) are used as catalysts. After oxidation, the BOD/COD ratio in the proposed process increased from 0.03 to 0.25, indicating that the biodegradability of the leachate was improved. By comparing the efficiency on COD removal and economical aspect of the proposed Pd-based in-situ process with traditional Fenton, electro-Fenton and UV-Fenton for leachate treatments, the proposed Pd-based in-situ process has potential economic advantages over other advanced oxidation processes while the COD removal efficiency was maintained. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous removal of aniline, nitrogen and phosphorus in aniline-containing wastewater treatment by using sequencing batch reactor.

PubMed

Jiang, Yu; Wang, Hongyu; Shang, Yu; Yang, Kai

2016-05-01

The high removal efficiencies of traditional biological aniline-degrading systems always lead to accumulation of ammonium. In this study, simultaneous removal of aniline, nitrogen and phosphorus in a single sequencing batch reactor was achieved by using anaerobic/aerobic/anoxic (A/O/A) operational process. The removal efficiencies of COD, NH4(+)-N, TN, TP were over 95.80%, 83.03%, 87.13%, 90.95%, respectively in most cases with 250mgL(-1) of initial aniline at 6h cycle when DO was 5.5±0.5mgL(-1). Aniline was able to be completely degraded when initial concentrations were less than 750mgL(-1). When DO increased, the removal rate of NH4(+)-N and TP slightly increased along with the moderate decrease of removal efficiencies of TN. The variation of HRT had obvious influence on removal performance of pollutants. The system showed high removal efficiencies of aniline, COD and nutrients during the variation of operating conditions, which might contribute to disposal of aniline-rich industrial wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

A case study of coupling upflow anaerobic sludge blanket (UASB) and ANITA™ Mox process to treat high-strength landfill leachate.

PubMed

Lu, Ting; George, Biju; Zhao, Hong; Liu, Wenjun

2016-01-01

A pilot study was conducted to study the treatability of high-strength landfill leachate by a combined process including upflow anaerobic sludge blanket (UASB), carbon removal (C-stage) moving bed biofilm reactor (MBBR) and ANITA™ Mox process. The major innovation on this pilot study is the patent-pending process invented by Veolia that integrates the above three unit processes with an effluent recycle stream, which not only maintains the low hydraulic retention time to enhance the treatment performance but also reduces inhibiting effect from chemicals present in the high-strength leachate. This pilot study has demonstrated that the combined process was capable of treating high-strength leachate with efficient chemical oxygen demand (COD) and nitrogen removals. The COD removal efficiency by the UASB was 93% (from 45,000 to 3,000 mg/L) at a loading rate of 10 kg/(m(3)·d). The C-stage MBBR removed an additional 500 to 1,000 mg/L of COD at a surface removal rate (SRR) of 5 g/(m(2)·d) and precipitated 400 mg/L of calcium. The total inorganic nitrogen removal efficiency by the ANITA Mox reactor was about 70% at SRR of 1.0 g/(m(2)·d).

Enhanced energy recovery from cassava ethanol wastewater through sequential dark hydrogen, photo hydrogen and methane fermentation combined with ammonium removal.

PubMed

Lin, Richen; Cheng, Jun; Yang, Zongbo; Ding, Lingkan; Zhang, Jiabei; Zhou, Junhu; Cen, Kefa

2016-08-01

Cassava ethanol wastewater (CEW) was subjected to sequential dark H2, photo H2 and CH4 fermentation to maximize H2 production and energy yield. A relatively low H2 yield of 23.6mL/g soluble chemical oxygen demand (CODs) was obtained in dark fermentation. To eliminate the inhibition of excessive NH4(+) on sequential photo fermentation, zeolite was used to remove NH4(+) in residual dark solution (86.5% removal efficiency). The treated solution from 5gCODs/L of CEW achieved the highest photo H2 yield of 369.7mL/gCODs, while the solution from 20gCODs/L gave the lowest yield of 259.6mL/gCODs. This can be explained that photo H2 yield was correlated to soluble metabolic products (SMPs) yield in dark fermentation, and specific SMPs yield decreased from 38.0 to 18.1mM/g CODs. The total energy yield significantly increased to 8.39kJ/gCODs by combining methanogenesis with a CH4 yield of 117.9mL/gCODs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system.

PubMed

Kheradmand, S; Karimi-Jashni, A; Sartaj, M

2010-06-01

The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during 8 months experiment (COD concentrations of 48,552-62,150 mg/L). It was found that the system could reduce the COD of the leachate by 94% at a loading rate of 2.25g COD/L/d and 93% at loading rate of 3.37g COD/L/d. The anaerobic digester treatment was quite effective in removing Fe, Cu, Mn, and Ni. However, in the case of Zn, removal efficiency was about 50%. For the rest of the HMs the removal efficiencies were in the range 88.8-99.9%. Ammonia reduction did not occur in anaerobic digesters. Anaerobic reactors increased alkalinity about 3.2-4.8% in the 1st digester and 1.8-7.9% in the 2nd digester. In activated sludge unit, alkalinity and ammonia removal efficiency were 49-60% and 48.6-64.7%, respectively. Methane production rate was in the range of 0.02-0.04, 0.04-0.07, and 0.02-0.04 L/g COD(rem) for the 1st digester, the 2nd digester, and combination of both digesters, respectively; the methane content of the biogas varied between 60% and 63%. Copyright 2010 Elsevier Ltd. All rights reserved.

Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kheradmand, S.; Karimi-Jashni, A., E-mail: akarimi@shirazu.ac.i; Sartaj, M.

2010-06-15

The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during 8 months experiment (COD concentrations of 48,552-62,150 mg/L). It was found that the system could reduce the COD of the leachate by 94% at a loading rate of 2.25 g COD/L/d and 93% at loading rate of 3.37 g COD/L/d.more » The anaerobic digester treatment was quite effective in removing Fe, Cu, Mn, and Ni. However, in the case of Zn, removal efficiency was about 50%. For the rest of the HMs the removal efficiencies were in the range 88.8-99.9%. Ammonia reduction did not occur in anaerobic digesters. Anaerobic reactors increased alkalinity about 3.2-4.8% in the 1st digester and 1.8-7.9% in the 2nd digester. In activated sludge unit, alkalinity and ammonia removal efficiency were 49-60% and 48.6-64.7%, respectively. Methane production rate was in the range of 0.02-0.04, 0.04-0.07, and 0.02-0.04 L/g COD{sub rem} for the 1st digester, the 2nd digester, and combination of both digesters, respectively; the methane content of the biogas varied between 60% and 63%.« less

Combined heterogeneous Electro-Fenton and biological process for the treatment of stabilized landfill leachate.

PubMed

Baiju, Archa; Gandhimathi, R; Ramesh, S T; Nidheesh, P V

2018-03-15

Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm 2 . Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L. Copyright © 2018 Elsevier Ltd. All rights reserved.

Treatment of fruit-juice industry wastewater in a two-stage anaerobic hybrid (AH) reactor system followed by a sequencing batch reactor (SBR).

PubMed

Tawfik, A; El-Kamah, H

2012-01-01

This study has been carried out to assess the performance of a combined system consisting of an anaerobic hybrid (AH) reactor followed by a sequencing batch reactor (SBR) for treatment of fruit-juice industry wastewater at a temperature of 26 degrees C. Three experimental runs were conducted in this investigation. In the first experiment, a single-stage AH reactor was operated at a hydraulic retention time (HRT) of 10.2 h and organic loading rate (OLR) of 11.8 kg COD m(-3) d(-1). The reactor achieved a removal efficiency of 42% for chemical oxygen demand (COD), 50.8% for biochemical oxygen demand (BOD5), 50.3% for volatile fatty acids (VFA) and 56.4% for total suspended solids (TSS). In the second experiment, two AH reactors connected in series achieved a higher removal efficiency for COD (67.4%), BOD5 (77%), and TSS (71.5%) at a total HRT of 20 h and an OLR of 5.9 kg COD m(-3) d(-1). For removal of the remaining portions of COD, BOD5 and TSS from the effluent of the two-stage AH system, a sequencing batch reactor (SBR) was investigated as a post-treatment unit. The reactor achieved a substantial reduction in total COD, resulting in an average effluent concentration of 50 mg L(-1) at an HRT of 11 h and OLR of 5.3 kg COD m(-3) d(-1). Almost complete removal of total BOD5 and oil and grease was achieved, i.e. 10 mg L(-1) and 1.2 mg L(-1), respectively, remained in the final effluent of the SBR.

Influence of COD/sulfate ratios on the integrated reactor system for simultaneous removal of carbon, sulfur and nitrogen.

PubMed

Yuan, Ye; Chen, Chuan; Zhao, Youkang; Wang, Aijie; Sun, Dezhi; Huang, Cong; Liang, Bin; Tan, Wenbo; Xu, Xijun; Zhou, Xu; Lee, Duu-Jung; Ren, Nanqi

2015-01-01

An integrated reactor system was developed for the simultaneous removal of carbon, sulfur and nitrogen from sulfate-laden wastewater and for elemental sulfur (S°) reclamation. The system mainly consisted of an expanded granular sludge bed (EGSB) for sulfate reduction and organic carbon removal (SR-CR), an EGSB for denitrifying sulfide removal (DSR), a biological aerated filter for nitrification and a sedimentation tank for sulfur reclamation. This work investigated the influence of chemical oxygen demand (COD)/sulfate ratios on the performance of the system. Influent sulfate and ammonium were fixed to the level of 600 mg SO(4)(2-) L⁻¹ and 120 mg NH(4)(+) L⁻¹, respectively. Lactate was introduced to generate COD/SO(4)(2-) = 0.5:1, 1:1, 1.5:1, 2:1, 3:1, 3.5:1 and 4:1. The experimental results indicated that sulfate could be efficiently reduced in the SR-CR unit when the COD/SO(4)(2-) ratio was between 1:1 and 3:1, and sulfate reduction was inhibited by the growth of methanogenic bacteria when the COD/SO(4)(2-) ratio was between 3.5:1 and 4:1. Meanwhile, the Org-C/S²⁻/NO(3)(-) ratios affected the S(0) reclamation efficiency in the DSR unit. When the influent COD/SO(4)(2-) ratio was between 1:1 and 3:1, appropriate Org-C/S²⁻/NO(3)(-) ratios could be achieved to obtain a maximum S° recovery in the DSR unit. For the microbial community of the SR-CR unit at different COD/SO(4)(2-) ratios, 16S rRNA gene-based high throughput Illumina MiSeq sequencing was used to analyze the diversity and potential function of the dominant species.

Integration of ozonation and an anaerobic sequencing batch reactor (AnSBR) for the treatment of cherry stillage.

PubMed

Alvarez, Pedro M; Beltrán, Fernando J; Rodríguez, Eva M

2005-01-01

Cherry stillage is a high strength organic wastewater arising from the manufacture of alcoholic products by distillation of fermented cherries. It is made up of biorefractory polyphenols in addition to readily biodegradable organic matter. An anaerobic sequencing batch reactor (AnSBR) was used to treat cherry stillage at influent COD ranging from 5 to 50 g/L. Different cycle times were selected to test biomass organic loading rates (OLR(B)), from 0.3 to 1.2 g COD/g VSS.d. COD and TOC efficiency removals higher than 80% were achieved at influent COD up to 28.5 g/L but minimum OLR(B) tested. However, as a result of the temporary inhibition of acetogens and methanogens, volatile fatty acids (VFA) noticeably accumulated and methane production came to a transient standstill when operating at influent COD higher than 10 g/L. At these conditions, the AnSBR showed signs of instability and could not operate efficiently at OLR(B) higher than 0.3 g COD/g VSS.d. A feasible explanation for this inhibition is the presence of toxic polyphenols in cherry stillage. Thus, an ozonation step prior to the AnSBR was observed to be useful, since more than 75% of polyphenols could be removed by ozone. The integrated process was shown to be a suitable treatment technology as the following advantages compared to the single AnSBR treatment were observed: greater polyphenols and color removals, higher COD and TOC removal rates thus enabling the process to effectively operate at higher OLR, higher degree of biomethanation, and good stability with less risk of acidification.

Winery wastewater treatment by combination of Cryptococcus laurentii and Fenton's reagent.

PubMed

Santos, Cátia; Lucas, Marco S; Dias, Albino A; Bezerra, Rui M F; Peres, José A; Sampaio, Ana

2014-12-01

Winery wastewaters (WW) have high levels of organic matter, resulting in high COD and BOD and suspended solids. This paper studies the combination of biological and chemical processes in WW treatment. Among 10 yeast isolates, Filobasidium sp. (AGG 577) and Cryptococcus laurentii (AGG 726) were selected due to their superior performance in COD removal. During WW degradation, COD and total polyphenols (TPP) content removal of 89-90% for Filobasidium sp. and 90-93% for C. laurentii were obtained. However, despite similar degradation efficiency for both yeasts, COD kinetics and pH evolution during treatment reveals that C. laurentii presents a faster response than Filobasidium sp. The toxicity (inhibition of Vibrio fischeri luminescence) of C. laurentii treated WW decreases to an inhibition value below 2.5%. However, treated WW exceeds the legal limits, making necessary an additional treatment. In this case, the selection of Fenton's reagent as a chemical final polish step process is a good compromise between efficiency and lower practical complexity. The best results for both COD and TPP removal were obtained with H2O2 initial concentration of 39.2mM and a H2O2:Fe(2+) molar ratio of 15:1. The combined C. laurentii - Fenton's reagent treatment of WW achieved a total reduction of 98% and 96%, for COD and TPP, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

The removal of COD and NH3-N from atrazine production wastewater treatment using UV/O3: experimental investigation and kinetic modeling.

PubMed

Jing, Liang; Chen, Bing; Wen, Diya; Zheng, Jisi; Zhang, Baiyu

2018-01-01

In this study, a UV/O 3 hybrid advanced oxidation system was used to remove chemical oxygen demand (COD), ammonia nitrogen (NH 3 -N), and atrazine (ATZ) from ATZ production wastewater. The removal of COD and NH 3 -N, under different UV and O 3 conditions, was found to follow pseudo-first-order kinetics with rate constants ranging from 0.0001-0.0048 and 0.0015-0.0056 min -1 , respectively. The removal efficiency of ATZ was over 95% after 180 min treatment, regardless the level of UV power. A kinetic model was further proposed to simulate the removal processes and to quantify the individual roles and contributions of photolysis, direct O 3 oxidation, and hydroxyl radical (OH·) induced oxidation. The experimental and kinetic modeling results agreed reasonably well with deviations of 12.2 and 13.1% for the removal of COD and NH 3 -N, respectively. Photolysis contributed appreciably to the degradation of ATZ, while OH· played a dominant role for the removal of both COD and NH 3 -N, especially in alkaline environments. This study provides insights into the treatment of ATZ containing wastewater using UV/O 3 and broadens the knowledge of kinetics of ozone-based advanced oxidation processes.

Removal of chemical oxygen demand, nitrogen, and heavy metals using a sequenced anaerobic-aerobic treatment of landfill leachates at 10-30 degrees C.

PubMed

Kalyuzhnyi, Sergey; Gladchenko, Marina; Epov, Andrey; Appanna, Vasu

2003-01-01

As a first step of treatment of landfill leachates (total chemical oxygen demand [COD]: 1.43-3.81 g/L; total nitrogen: 90-162 mg/L), performance of laboratory upflow anaerobic sludge bed reactors was investigated under mesophilic (30 degrees C), submesophilic (20 degrees C), and psychrophilic (10 degrees C) conditions. Under hydraulic retention times (HRTs) of about 0.3 d, when the average organic loading rates (OLRs) were about 5 g of COD/(L.d), the total COD removal accounted for 81% (on average) with the effluent concentrations close to the anaerobic biodegradability limit (0.25 g of COD/L) for mesophilic and submesophilic regimes. The psychrophilic treatment conducted under an average HRT of 0.34 d and an average OLR of 4.22 g of COD/(L.d) showed a total COD removal of 47%, giving effluents (0.75 g of COD/L) more suitable for subsequent biologic nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulfides inside the sludge bed. The application of aerobic/ anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated wastewater.

Application of microbial electrolysis cells to treat spent yeast from an alcoholic fermentation.

PubMed

Sosa-Hernández, Ornella; Popat, Sudeep C; Parameswaran, Prathap; Alemán-Nava, Gibrán Sidney; Torres, César I; Buitrón, Germán; Parra-Saldívar, Roberto

2016-01-01

Spent yeast (SY), a major challenge for the brewing industry, was treated using a microbial electrolysis cell to recover energy. Concentrations of SY from bench alcoholic fermentation and ethanol were tested, ranging from 750 to 1500mgCOD/L and 0 to 2400mgCOD/L respectively. COD removal efficiency (RE), coulombic efficiency (CE), coulombic recovery (CR), hydrogen production and current density were evaluated. The best treatment condition was 750mgCOD/LSY+1200mgCOD/L ethanol giving higher COD RE, CE, CR (90±1%, 90±2% and 81±1% respectively), as compared with 1500mgCOD/LSY (76±2%, 63±7% and 48±4% respectively); ethanol addition was significantly favorable (p value=0.011), possibly due to electron availability and SY autolysis. 1500mgCOD/LSY+1200mgCOD/L ethanol achieved higher current density (222.0±31.3A/m(3)) and hydrogen production (2.18±0.66 [Formula: see text] ) but with lower efficiencies (87±2% COD RE, 71.0±.4% CE). Future work should focus on electron sinks, acclimation and optimizing SY breakdown. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Achieving mainstream nitrogen removal through simultaneous partial nitrification, anammox and denitrification process in an integrated fixed film activated sludge reactor.

PubMed

Wang, Chao; Liu, Sitong; Xu, Xiaochen; Zhang, Chaolei; Wang, Dong; Yang, Fenglin

2018-07-01

The anaerobic ammonium oxidation (anammox) is becoming a critical technology for energy neutral in mainstream wastewater treatment. However, the presence of chemical oxygen demanding in influent would result in a poor nitrogen removal efficiency during the deammonification process. In this study, the simultaneous partial nitrification, anammox and denitrification process (SNAD) for mainstream nitrogen removal was investigated in an integrated fixed film activated sludge (IFAS) reactor. SNAD-IFAS process achieved a total nitrogen (TN) removal efficiency of 72 ± 2% and an average COD removal efficiency was 88%. The optimum COD/N ratio for mainstream wastewater treatment was 1.2 ± 0.2. Illumina sequencing analysis and activity tests showed that anammox and denitrifying bacteria were the dominant nitrogen removal microorganism in the biofilm and the high COD/N ratios (≥2.0) leaded to the proliferation of heterotrophic bacteria (Hydrogenophaga) and nitrite-oxidizing bacteria (Nitrospira) in the suspended sludge. Network analysis confirmed that anammox bacteria (Candidatus Kuenenia) could survive in organic matter environment due to that anammox bacteria displayed significant co-occurrence through positive correlations with some heterotrophic bacteria (Limnobacter) which could protect anammox bacteria from hostile environments. Overall, the results of this study provided more comprehensive information regarding the community composition and assemblies in SNAD-IFAS process for mainstream nitrogen removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ammoniacal nitrogen and COD removal from semi-aerobic landfill leachate using a composite adsorbent: fixed bed column adsorption performance.

PubMed

Halim, Azhar Abdul; Aziz, Hamidi Abdul; Johari, Megat Azmi Megat; Ariffin, Kamar Shah; Adlan, Mohd Nordin

2010-03-15

The performance of a carbon-mineral composite adsorbent used in a fixed bed column for the removal of ammoniacal nitrogen and aggregate organic pollutant (COD), which are commonly found in landfill leachate, was evaluated. The breakthrough capacities for ammoniacal nitrogen and COD adsorption were 4.46 and 3.23 mg/g, respectively. Additionally, the optimum empty bed contact time (EBCT) was 75 min. The column efficiency for ammoniacal nitrogen and COD adsorption using fresh adsorbent was 86.4% and 92.6%, respectively, and these values increased to 90.0% and 93.7%, respectively, after the regeneration process. (c) 2009 Elsevier B.V. All rights reserved.

Effect of persulfate and persulfate/H₂O₂ on biodegradability of an anaerobic stabilized landfill leachate.

PubMed

Hilles, Ahmed H; Abu Amr, Salem S; Hussein, Rim A; Arafa, Anwar I; El-Sebaie, Olfat D

2015-10-01

The current study investigated the effects of S2O8(2-) and S2O8(2-)/H2O2 oxidation processes on the biodegradable characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46% after S2O8(2-) oxidation (using 4.2 g S2O8(2-)/1g COD0, at pH 7, for 60 min reaction time and at 350 rpm shaking speed), and improved to 81% following S2O8(2-)/H2O2 oxidation process (using 5.88 g S2O8(2-) dosage, 8.63 g H2O2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of BOD5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S2O8(2-) and S2O8(2-)/H2O2 oxidation processes, respectively. The fractions of COD were determined before and after each oxidation processes (S2O8(2-) and S2O8(2-)/H2O2). The fraction of biodegradable COD(bi) increased from 36% in raw leachate to 57% and 68% after applying S2O8(2-) and S2O8(2-)/H2O2 oxidation, respectively. As for soluble COD(s), its removal efficiency was 39% and 78% following S2O8(2-) and S2O8(2-)/H2O2 oxidation, respectively. The maximum removal for particulate COD was 94% and was obtained after 120 min of S2O8(2-)/H2O2 oxidation. As a conclusion, S2O8(2-)/H2O2 oxidation could be an efficient method for improving the biodegradability of anaerobic stabilized leachate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effective removal of contaminants in landfill leachate membrane concentrates by coagulation.

PubMed

Long, Yuyang; Xu, Jing; Shen, Dongsheng; Du, Yao; Feng, Huajun

2017-01-01

Leachate membrane concentrates containing high concentrations of organics and trace toxic compounds pose a major threat to the environment, and their treatment is an urgent issue. In this work, various coagulants were used to treat leachate membrane concentrates. Appropriate pH values for treatments with FeCl 2 , FeSO 4 , polyaluminum chloride, and FeCl 3 were 3, 5, 5, and 4, respectively. FeCl 3 achieved the highest total organic carbon (TOC) removal efficiency. The effect of the various anions in ferric coagulants [FeCl 3 , Fe 2 (SO 4 ) 3 , and Fe(NO 3 ) 3 ] on the TOC removal efficiency was negligible. The main organics remaining in the leachate membrane concentrates after coagulation were humic and fulvic acids. The conditions for coagulation with FeCl 3 were optimized using the response surface method (RSM). The highest TOC, chemical oxygen demand (COD), and chromaticity reduction efficiencies, 81%, 82%, and 97%, respectively, were achieved at pH 4 using FeCl 3 (5 g L -1 ) and polyacrylamide (PAM; 0.07 g L -1 ). The COD of leachate membrane concentrates was reduced from 4000 to 718 mg L -1 . The mole ratio of removed COD and Fe(III) (2.4 mol) at 5 g L -1 FeCl 3 (pH 4, PAM 0.07 g L -1 ) was lower than that (3.8 mol) at 3 g L -1 FeCl 3 (pH 4, PAM 0.07 g L -1 ); based on the cost and COD removal efficiency, the latter conditions were the best choice. Our work provides guidelines for the treatment of leachate membrane concentrates in engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

Utilization of Natural Zeolite and Perlite as Landfill Liners for in Situ Leachate Treatment in Landfills

PubMed Central

Ozel, Ummukulsum; Akdemir, Andaç; Ergun, Osman Nuri

2012-01-01

The potential long term environmental impacts of a landfill on groundwater quality depend on its liner material properties. In case synthetic liner materials are damaged during the construction or operation, many of the original chemical and biological constituents are removed by filtration and the adsorptive action of natural liner materials such as natural zeolite, perlite and bentonite minerals. Before leachate treatment, reduction of these constituents is important not only to leachate percolation, but also treatment cost and efficiency. In this study, the pollutant removal efficiency from the leachate was investigated for natural natural zeolite, expanded perlite and bentonite. Experimental studies was performed in boxes made of glass and with 1:10 sloping. Leachate quantity was determined and pH, electrical conductivity (EC), nitrate (NO3-N), ammonium-nitrogen (NH4-N), phosphate (PO4), chemical oxygen demand (COD) and organic matter in leachate samples were measured and the measurement was compared with control process (System 4). The results showed that natural zeolite was effective in removing NO3, NH4, PO4, COD and organic matter with removal efficiencies of 91.20, 95.6, 95.5, 83.4 and 87.8%, respectively. Expanded perlite has high efficiency removing of NO3, PO4 and COD 83.2, 91.0 and 62.5%, respectively, but it was unsuccessful in reducing NH4 (1.5%). PMID:22754458

Utilization of natural zeolite and perlite as landfill liners for in situ leachate treatment in landfills.

PubMed

Ozel, Ummukulsum; Akdemir, Andaç; Ergun, Osman Nuri

2012-05-01

The potential long term environmental impacts of a landfill on groundwater quality depend on its liner material properties. In case synthetic liner materials are damaged during the construction or operation, many of the original chemical and biological constituents are removed by filtration and the adsorptive action of natural liner materials such as natural zeolite, perlite and bentonite minerals. Before leachate treatment, reduction of these constituents is important not only to leachate percolation, but also treatment cost and efficiency. In this study, the pollutant removal efficiency from the leachate was investigated for natural natural zeolite, expanded perlite and bentonite. Experimental studies was performed in boxes made of glass and with 1:10 sloping. Leachate quantity was determined and pH, electrical conductivity (EC), nitrate (NO(3)-N), ammonium-nitrogen (NH(4)-N), phosphate (PO(4)), chemical oxygen demand (COD) and organic matter in leachate samples were measured and the measurement was compared with control process (System 4). The results showed that natural zeolite was effective in removing NO(3), NH(4), PO(4), COD and organic matter with removal efficiencies of 91.20, 95.6, 95.5, 83.4 and 87.8%, respectively. Expanded perlite has high efficiency removing of NO(3), PO(4) and COD 83.2, 91.0 and 62.5%, respectively, but it was unsuccessful in reducing NH(4) (1.5%).

Aspergillus niger P6 and Rhodotorula mucilaginosa CH4 used for olive mill wastewater (OMW) biological treatment in single pure and successive cultures.

PubMed

Jarboui, Raja; Magdich, Salwa; Ayadi, Raja Jarboui; Gargouri, Ali; Gharsallah, Néji; Ammar, Emna

2013-01-01

The aim of this study was to investigate the Rhodotorula mucilaginosa CH4 and Aspergillus niger P6 abilities to purify olive mill wastewater (OMW) in single pure and mixed cultures during the treatment. Both fungi were molecularly identified. OMW was used at five dilutions from 5% to 30% with chemical oxygen demand (COD) ranging from 11,600 to 24,600 mg L(-1). Firstly, each fungus was used separately, then they were successively used to treat the OMW. In single pure culture, A. niger showed a better efficiency in OMW purification than R. mucilaginosa. Furthermore, when successively used, the two studied strains exhibited improvements in the decrease of COD, polyphenolic compounds concentration and effluent colour. COD removals were 95.68-56.71% by R. mucilaginosa and 98.02-69.51% by A. niger for OMW dilutions varying from 5% to 30%. Both strains showed an important polyphenolic compounds removal of 83-45% by R. mucilaginosa and 94-58% by A. niger, in accordance with the OMW COD initially used. The COD and phenolic compound removals fitted simple equation models, with high regression coefficients. The strains' growth kinetics decreased according to the OMW concentration, but, when successively used, fungal growth was improved, allowing efficient effluent treatment.

Treatment of soft drink process wastewater by ozonation, ozonation-H₂O₂ and ozonation-coagulation processes.

PubMed

García-Morales, M A; Roa-Morales, G; Barrera-Díaz, C; Balderas-Hernández, P

2012-01-01

In this research, we studied the treatment of wastewater from the soft drink process using oxidation with ozone. A scheme composed of sequential ozonation-peroxide, ozonation-coagulation and coagulation-ozonation treatments to reduce the organic matter from the soft drink process was also used. The samples were taken from the conventional activated sludge treatment of the soft drink process, and the experiments using chemical oxidation with ozone were performed in a laboratory using a reactor through a porous plate glass diffuser with air as a feedstock for the generation of ozone. Once the sample was ozonated, the treatments were evaluated by considering the contact time, leading to greater efficiency in removing colour, turbidity and chemical oxygen demand (COD). The effect of ozonation and coagulant coupled with treatment efficiency was assessed under optimal conditions, and substantial colour and turbidity removal were found (90.52% and 93.33%, respectively). This was accompanied by a 16.78% reduction in COD (initial COD was 3410 mg/L). The absorbance spectra of the oxidised products were compared using UV-VIS spectroscopy to indicate the level of oxidation of the wastewater. We also determined the kinetics of decolouration and the removal of turbidity with the best treatment. The same treatment was applied to the sample taken from the final effluent of the activated sludge system, and a COD removal efficiency of 100% during the first minute of the reaction with ozone was achieved. As a general conclusion, we believe that the coagulant polyaluminum chloride - ozone (PAC- ozone) treatment of wastewater from the manufacturing of soft drinks is the most efficient for removing turbidity and colour and represents an advantageous option to remove these contaminants because their removal was performed in minutes compared to the duration of traditional physical, chemical and biological processes that require hours or days.

Reactor performance and microbial community of an EGSB reactor operated at 20 and 15 degrees C.

PubMed

Xing, W; Zuo, J-E; Dai, N; Cheng, J; Li, J

2009-09-01

To investigate the effects of low temperatures on the performance and microbial community of anaerobic wastewater treatment. An expanded granular sludge bed (EGSB) reactor was employed to treat synthetic brewery wastewater at 20 and 15 degrees C. Reactor performance was represented by chemical oxygen demand (COD) removal efficiency, while the microbial community was analysed using denaturing gradient gel electrophoresis (DGGE) and clone technology. When the hydraulic retention time (HRT) was maintained at 18 h, COD removal efficiencies above 85% were obtained at both 20 and 15 degrees C, with influent COD concentrations up to 7300 and 4100 mg l(-1), respectively. At 15 degrees C, the COD removal efficiency was more easily manipulated by increasing the influent COD concentration. DGGE and clone results for both temperatures revealed that Methanosaeta and Methanobacterium were two dominant methanogens, and that the majority of the eubacterial clones were represented by Firmicutes. When the temperature decreased from 20 to 15 degrees C, both archaeal and eubacterial communities had higher diversity, and the proportion of Methanosaeta (acetate-utilizing methanogens) decreased markedly from 60.0% to 49.3%, together with an increase in proportions of hydrogen-utilizing methanogens (especially Methanospirillum). The feasibility of psychrophilic anaerobic treatment of low and medium strength organic wastewaters was demonstrated, although lower temperature could significantly affect both reactor performance and the anaerobic microbial community. The findings enrich the theory involving the microbial community and the application of anaerobic treatment in a psychrophilic environment.

Phenolic refinery wastewater biodegradation by an expanded granular sludge bed reactor.

PubMed

Almendariz, F J; Meraz, M; Olmos, A D; Monroy, O

2005-01-01

Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SW(CO2)) and 83% of H2S was striped during this procedure, remaining an aromatic portion that contained 2123, 2730 and 1379 mg L(-1) of phenol, p-cresol and o-cresol, respectively. The mixture was teated anaerobically in an EGSB reactor fed with 1.5 gCOD L(-1) d(-1), without mineral supplements causing loss of COD removal efficiency that dropped to 23%, methane production ceased and no phenol or cresols were biodegraded. The EGSB experiments were resumed by feeding the reactor with nutrients and phenol at 1.0 gCOD L(-1) d(-1). The mixture SC/SWco2 added to the phenol load, was step increased from 0.10 to 0.87 gCODL(-1) d(-1) maximum. When total organic load was increased to 1.6, COD removal efficiency was 90% and at the highest load attained, 1.87, efficiency dropped to 23% attributed to the toxic effect produced by cresols.

Kinetic of carbonaceous substrate in an upflow anaerobic sludge sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP).

PubMed

Sponza, Delia Teresa; Uluköy, Ayşen

2008-01-01

The performance of an upflow anaerobic sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP) was evaluated at different hydraulic retention times (HRTs) using synthetic wastewater in order to obtain the growth substrate (glucose-COD) and 2,4 DCP removal kinetics. Treatment efficiencies of the UASB reactor were investigated at different hydraulic retention times (2-20 h) corresponding to a food to mass (F/M) ratio of 1.2-1.92 g-COD g(-1) VSS day(-1). A total of 65-83% COD removal efficiencies were obtained at HRTs of 2-20 h. In all, 83% and 99% 2,4 DCP removals were achieved at the same HRTs in the UASB reactor. Conventional Monod, Grau Second-order and Modified Stover-Kincannon models were applied to determine the substrate removal kinetics of the UASB reactor. The experimental data obtained from the kinetic models showed that the Monod kinetic model is more appropriate for correlating the substrate removals compared to the other models for the UASB reactor. The maximum specific substrate utilization rate (k) (mg-COD mg(-1) SS day(-1)), half-velocity concentration (K(s)) (mg COD l(-1)), growth yield coefficient (Y) (mg mg(-1)) and bacterial decay coefficient (b) (day(-1)) were 0.954 mg-COD mg(-1) SS day(-1), 560.29 mg-COD l(-1), 0.78 mg-SS g(-1)-COD, 0.093 day(-1) in the Conventional Monod kinetic model. The second-order kinetic coefficient (k(2)) was calculated as 0.26 day(-1) in the Grau reaction kinetic model. The maximum COD removal rate constant (U(max)) and saturation value (K(B)) were calculated as 7.502 mg CODl(-1)day(-1) and 34.56 mg l(-1)day(-1) in the Modified Stover-Kincannon Model. The (k)(mg-2,4 DCP mg(-1) SS day(-1)), (K(s)) (mg 2,4 DCPl(-1)), (Y) (mg SS mg(-1) 2,4 DCP) and (k(d)) (day(-1)) were 0.0041 mg-2,4 DCP mg(-1) SS day(-1), 2.06 mg-COD l(-1), 0.0017 mg-SS mg(-1) 2,4 DCP and 3.1 x 10(-5) day(-1) in the Conventional Monod kinetic model for 2,4 DCP degradation. The second-order kinetic coefficient (k(2)) was calculated as 0.30 day(-1) in the Grau reaction kinetic model. The maximum 2,4 DCP removal rate constant (U(max)) and saturation value (K(B)) were calculated as 0.01 mg COD l(-1) day(-1) and 9.8 x 10(-3) mg l(-1) day(-1) in the Modified Stover-Kincannon model.

[Research on removal efficiency of Cd (II)-bearing wastewater by sulfate-reducing biological filter].

PubMed

Wu, Xuan; Tan, Ke-Yan; Hu, Xi-Jia; Gu, Yun; Yang, Hong

2014-04-01

At the temperature of 18.0-22.3 degrees C, biological carriers were produce from pure SRB and zeolite by the embedding immobilized method, and a sulfate-reducing biological filter filled with filter carriers was built to treat cadmium-containing wastewater. Experimental research on removal efficiency of Cd2+, COD and SO4(2-) in wastewater by the biological filter was carried out after SRB domestication. Results show that cadmium can be removed satisfactorily from wastewater using SRB by the biological filter filled with sulfate-reducing bacteria. When the filtration rate was 0.4 m x h(-1) and the cadmium concentration in wastewater was not more than 15 mg x L(-1), the processing efficiency was the best. In the formal running period, the removal rates of Cd2+, COD and SO4(2-) by the biological filter were more than 99%, 75% and 50%. The effluent Cd2+ concentration was less than 0.1 mg x L(-1), which could meet the cadmium emission requirements in the wastewater quality standards for discharge to municipal sewers (CJ 343-2010). The removal of Cd2+, COD and SO4(2-) by biological filter mainly occurs in the top 60 cm of the filter bed during stable operation. When the filtration rate was less than 0.6 m x h(-1), Cd(2+) can be removed by the biological filter with high efficiency and stability.

Hybrid process, electrocoagulation-biofiltration for landfill leachate treatment.

PubMed

Dia, Oumar; Drogui, Patrick; Buelna, Gerardo; Dubé, Rino

2018-05-01

Landfill leachates are known for their high and complex composition of organic, inorganic and microbial pollutants. As a result, it is quite challenging to treat these effluents by using only one treatment process. A combining approach is generally required to treat efficiently these wastewaters and comply with the discharge standards. In this present study, electrocoagulation (EC) and biofiltration (BF) processes were sequentially used to treat landfill leachate. EC process has been able to remove 37 ± 2% of the initial total COD. A fractionation of organic compounds showed that EC was particularly efficient to remove insoluble COD and humic acids. In addition, other pollutants such as turbidity, true color, Zn and phosphorus were significantly reduced by EC with 82 ± 2.7%, 60 ± 13%, 95 ± 2.6% and 82 ± 5.5% of removal respectively. The subsequent treatment by BF process led to completely removal of ammonia pollution (>99% of NH 4 removal) and a partial removal of dissolved organic compounds (42 ± 7% of COD removal). The hybrid process EC/BF could form the basis of a process capable of removing organic and inorganic pollutants from many refractory wastewaters (mature landfill leachates, industrial and municipal wastewaters). Copyright © 2018 Elsevier Ltd. All rights reserved.

Management of wastewater from the vegetable dehydration industry in Egypt--a case study.

PubMed

El-Gohary, Fatma; El-Kamah, Hala; Abdel Wahaab, Rifaat; Mahmoud, Mohamed; Ibrahim, Hamdy A

2012-01-01

Management of wastewater from the vegetable dehydration industry was the subject of this study. A continuous monitoring programme for wastewater was carried out for almost four months. The characterization of the wastewater indicated that the vegetable dehydration wastewater contains moderate concentrations of organics, solids and nutrients. The wastewater was subjected to three different treatment processes, namely aerobic treatment, anaerobic treatment and chemical coagulation-flocculation treatment. For aerobic treatment, the removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and total suspended solids (TSS) was accomplished within 5 h, and no further reduction was observed after that, with the steady state COD and BOD5 removal efficiencies being 95% +/- 10% and 97% +/- 8%, respectively. For anaerobic treatment, the removal efficiencies for COD, BOD5 and TSS were 67-81%, 70-86% and 56-69%, respectively at hydraulic retention times (HRTs) of 5, 6 and 8 h. Chemical coagulation-flocculation treatment also achieved good results. The COD removal efficiency was 72%, 51% and 75% for ferric chloride (56 g/m3 of wastewater), lime (140 g/m3 of wastewater) and ferric chloride aided with lime (100 g/m3 for ferric chloride and 200 g/m3 for lime), respectively. The corresponding TSS removal values were 92% +/- 17%, 20% +/- 7% and 93% +/- 9%. Based on the available results and the seasonally operated mode of this industry in Egypt, the chemical coagulation-flocculation process is therefore considered to be moste applicable from a technical point of view and for the simplicity of operation and maintenance.

Hybrid MF and membrane bioreactor process applied towards water and indigo reuse from denim textile wastewater.

PubMed

Couto, Carolina Fonseca; Marques, Larissa Silva; Balmant, Janine; de Oliveira Maia, Andreza Penido; Moravia, Wagner Guadagnin; Santos Amaral, Miriam Cristina

2018-03-01

This work investigates the application of a microfiltration (MF)-membrane bioreactor (MBR) hybrid process for textile dyeing process wastewater reclamation. The indigo blue dye was efficiently retained by the MF membrane (100%), which allows its recovery from the concentrate stream. MF promotes 100% of colour removal, and reduces the chemical oxygen demand (COD) and conductivity by about 65% and 25%, respectively, and improves the wastewater biodegradability. MF flux decline was mostly attributed to concentration polarization and the chemical cleaning was efficient enough to recover initial hydraulic resistance. The MBR provides to be a stable process maintaining its COD and ammonia removal efficiency (73% and 100%, respectively) mostly constant throughout and producing a permeate that meets the reuse criteria for some industry activities, such as washing-off and equipment washdown. The use of an MF or ultrafiltration (UF) membrane in the MBR does not impact the MBR performance in terms of COD removal. Although the membrane of MBR-UF shows permeability lower than MBR-MF membrane, the UF membrane contributes to a more stable operation in terms of permeability.

Combined anaerobic-aerobic treatment of landfill leachates under mesophilic, submesophilic and psychrophilic conditions.

PubMed

Kalyuzhnyi, S; Gladchenko, M; Epov, A

2003-01-01

As a first step of treatment of landfill leachates (total COD--1,430-3,810 mg/l, total nitrogen 90-162 mg/l), a performance of laboratory UASB reactors has been investigated under mesophilic (30 degrees C), sub-mesophilic (20 degrees C) and psychrophilic (10 degrees C) conditions. Under hydraulic retention times (HRT) of around 7 h, when the average organic loading rates (OLR) were around 5 g COD/l/day, the total COD removal accounted for 81% (on the average) with the effluent concentrations close to anaerobic biodegradability limit (0.25 g COD/l) for mesophilic and sub-mesophilic regimes. The psychrophilic treatment conducted under the average HRT of 8 h and the average OLR of 4.22 g COD/l/day showed a total COD removal of 47% producing the effluents (0.75 g COD/l) more suitable for subsequent biological nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulphides inside the sludge bed. The application of aerobic/anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated wastewater.

Nitrogen removal performance and microbial community of an enhanced multistage A/O biofilm reactor treating low-strength domestic wastewater.

PubMed

Chen, Han; Li, Ang; Wang, Qiao; Cui, Di; Cui, Chongwei; Ma, Fang

2018-06-01

The low-strength domestic wastewater (LSDW) treatment with low chemical oxygen demand (COD) has drawn extensive attention for the poor total nitrogen (TN) removal performance. In the present study, an enhanced multistage anoxic/oxic (A/O) biofilm reactor was designed to improve the TN removal performance of the LSDW treatment. Efficient nitrifying and denitrifying biofilm carriers were cultivated and then filled into the enhanced biofilm reactor as the sole microbial source. Step-feed strategy and internal recycle were adopted to optimize the substrate distribution and the organics utilization. Key operational parameters were optimized to obtain the best nitrogen and organics removal efficiencies. A hydraulic retention time of 8 h, an influent distribution ratio of 2:1 and an internal recycle ratio of 200% were tested as the optimum parameters. The ammonium, TN and COD removal efficiencies under the optimal operational parameters separately achieved 99.75 ± 0.21, 59.51 ± 1.95 and 85.06 ± 0.79% with an organic loading rate at around 0.36 kg COD/m 3  d. The high-throughput sequencing technology confirmed that nitrifying and denitrifying biofilm could maintain functional bacteria in the system during long-period operation. Proteobacteria and Bacteroidetes were the dominant phyla in all the nitrifying and denitrifying biofilm samples. Nitrosomonadaceae_uncultured and Nitrospira sp. stably existed in nitrifying biofilm as the main nitrifiers, while several heterotrophic genera, such as Thauera sp. and Flavobacterium sp., acted as potential genera responsible for TN removal in denitrifying biofilm. These findings suggested that the enhanced biofilm reactor could be a promising route for the treatment of LSDW with a low COD level.

Effects of influent C/N ratios and treatment technologies on integral biogas upgrading and pollutants removal from synthetic domestic sewage.

PubMed

Xu, Jie; Wang, Xue; Sun, Shiqing; Zhao, Yongjun; Hu, Changwei

2017-09-07

Three different treatment technologies, namely mono-algae culture, algal-bacterial culture, and algal-fungal culture, were applied to remove pollutants form synthetic domestic sewage and to remove CO 2 from biogas in a photobioreactor. The effects of different initial influent C/N ratios on microalgal growth rates and pollutants removal efficiencies by the three microalgal cultures were investigated. The best biogas upgrading and synthetic domestic sewage pollutants removal effect was achieved in the algal-fungal system at the influent C/N ratio of 5:1. At the influent C/N ratio of 5:1, the algal-fungal system achieved the highest mean chemical oxygen demand (COD) removal efficiency of 81.92% and total phosphorus (TP) removal efficiency of 81.52%, respectively, while the algal-bacterial system demonstrated the highest mean total nitrogen (TN) removal efficiency of 82.28%. The average CH 4 concentration in upgraded biogas and the removal efficiencies of COD, TN, and TP were 93.25 ± 3.84% (v/v), 80.23 ± 3.92%, 75.85 ± 6.61%, and 78.41 ± 3.98%, respectively. These results will provide a reference for wastewater purification ad biogas upgrading with microalgae based technology.

Efficient Utilization of Waste Carbon Source for Advanced Nitrogen Removal of Landfill Leachate

PubMed Central

Yin, Wenjun; Tan, Fengxun

2017-01-01

A modified single sequencing batch reactor (SBR) was developed to remove the nitrogen of the real landfill leachate in this study. To take the full advantage of the SBR, stir phase was added before and after aeration, respectively. The new mechanism in this experiment could improve the removal of nitrogen efficiently by the utilization of carbon source in the raw leachate. This experiment adopts the SBR process to dispose of the real leachate, in which the COD and ammonia nitrogen concentrations were about 3800 mg/L and 1000 mg/L, respectively. Results showed that the removal rates of COD and total nitrogen were above 85% and 95%, respectively, and the effluent COD and total nitrogen were less than 500 mg/L and 40 mg/L under the condition of not adding any carbon source. Also, the specific nitrogen removal rate was 1.48 mgN/(h·gvss). In this process, polyhydroxyalkanoate (PHA) as a critical factor for the highly efficient nitrogen removal (>95%) was approved to be the primary carbon source in the sludge. Because most of the organic matter in raw water was used for denitrification, in the duration of this 160-day experiment, zero discharge of sludge was realized when the effluent suspended solids were 30–50 mg/L. PMID:29435456

Sodium hypochlorite as an alternative to hydrogen peroxide in Fenton process for industrial scale.

PubMed

Behin, Jamshid; Akbari, Abbas; Mahmoudi, Mohsen; Khajeh, Mehdi

2017-09-15

In present work, the treatment of aromatic compounds of simulated wastewater was performed by Fenton and NaOCl/Fe 2+ processes. The model solution was prepared based on the wastewater composition of Diisocyanate unit of Karoon Petrochemical Company/Iran containing Diamino-toluenes, Nitro-phenol, Mononitro-toluene, Nitro-cresol, and Dinitro-toluene. Experiments were conducted in a batch mode to examine the effects of operating variables such as pH, oxidant dosages, ferrous ion concentration and numbers of feeding on COD removal. Taguchi experimental design was used to determine the optimum conditions. The COD removal efficiency under optimum conditions (suggested by Taguchi design) in Fenton and NaOCl/Fe 2+ processes was 88.7% and 83.4%, respectively. The highest contribution factor in Fenton process belongs to pH (47.47%) and in NaOCl/Fe 2+ process belongs to NaOCl/pollutants (50.26%). High regression coefficient (R 2 : 0.98) obtained for Taguchi method, indicates that models are statistically significant and are in well agreement with each other. The NaOCl/Fe 2+ process utilizing a conventional oxidant, in comparison to hydrogen peroxide, is an efficient cost effective process for COD removal from real wastewater, although the removal efficiency is not as high as in Fenton process; however it is a suitable process to replace Fenton process in industrial scale for wastewater involved aromatic compounds with high COD. This process was successfully applied in Karoon Petrochemical Company/Iran. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of temperature on the efficiency of the thermo- and mesophilic aerobic batch biodegradation of high-strength distillery wastewater (potato stillage).

PubMed

Krzywonos, Małgorzata; Cibis, Edmund; Miśkiewicz, Tadeusz; Kent, Chris A

2008-11-01

The objective of the study was to assess the effect of temperature on the extent of aerobic batch biodegradation of potato stillage with a mixed culture of bacteria of the genus Bacillus. The experiments were performed in a 5-l stirred-tank reactor at 20, 30, 35, 40, 45, 50, 55, 60, 63 and 65 degrees C with the pH of 7. Only at 65 degrees C, no reduction in chemical oxygen demand (COD) was found to occur. Over the temperature range of 20-63 degrees C, the removal efficiency was very high (with an extent of COD reduction following solids separation that varied between 77.57% and 89.14% after 125 h). The process ran at the fastest rate when the temperature ranged from 30 to 45 degrees C; after 43 h at the latest, COD removal amounted to 90% of the final removal efficiency value obtained for the process. At 20, 55, 60 and 63 degrees C, a 90% removal was attained after 80 h. Two criteria were proposed for the identification of the point in time when the process is to terminate. One of these consists in maximising the product of the extent of COD reduction and the extent of N-NH4 content reduction. The other criterion is a simplified one and involves the search for the minimal value of N-NH4 concentration.

Optimizing COD removal from greywater by photoelectro-persulfate process using Box-Behnken design: assessment of effluent quality and electrical energy consumption.

PubMed

Ahmadi, Mehdi; Ghanbari, Farshid

2016-10-01

Greywater (GW) is a potential source for water reuse in various applications. However, GW treatment is still a vital issue in water reuse in cases of environmental standards and risk to public health. This study investigates optimization and modeling of a hybrid process for COD removal from GW. Persulfate (PS) was simultaneously activated by electrogenerated ferrous ion (EC) and UV to generate sulfate radical. Photoelectro-persulfate (PEPS) was optimized by Box-Behnken design and the effects of four variables (pH, PS dosage, current density, and electrolysis time) were evaluated on COD removal. The results and several coefficients showed that the obtained model was acceptable for predicting the COD removal. Moreover, under optimum conditions (pH = 6.9, PS = 8.8 mM, current density = 2.0 mA/cm(2), and 49.3 min electrolysis time), BOD5, turbidity, TSS, phosphate, and UV254 were effectively removed and COD and BOD5 values reached to discharge standards. Different configurations of the processes were assessed for COD removal. The order of COD removal efficiency followed: PS < Fe(II) < UV/PS ≤ Fe(II)/PS < Fe(II)/PS/UV < electrocoagulation ≤ electrocoagulation/UV < electro-PS < PEPS. The monitoring PS concentration during 60 min reaction time in the aforesaid processes indicated that PEPS could remarkably activate PS. The solution pH was also monitored and related results revealed that the presence of PS during the 10 min first time decreased pH value while production of hydroxide ion at cathode increased pH significantly. Finally, the contribution of electrochemical process in the electrical energy consumption was far less than that of photolysis process in hybrid PEPS process.

Treatment of synthetic wastewater and hog waste with reduced sludge generation by the multi-environment BioCAST technology.

PubMed

Yerushalmi, L; Alimahmoodi, M; Mulligan, C N

2013-01-01

Simultaneous removal of carbon, nitrogen and phosphorus was examined along with reduced generation of biological sludge during the treatment of synthetic wastewater and hog waste by the BioCAST technology. This new multi-environment wastewater treatment technology contains both suspended and immobilized microorganisms, and benefits from the presence of aerobic, microaerophilic, anoxic and anaerobic conditions for the biological treatment of wastewater. The influent concentrations during the treatment of synthetic wastewater were 1,300-4,000 mg chemical oxygen demand (COD)/L, 42-115 mg total nitrogen (TN)/L, and 19-40 mg total phosphorus (TP)/L. The removal efficiencies reached 98.9, 98.3 and 94.1%, respectively, for carbon, TN and TP during 225 days of operation. The removal efficiencies of carbon and nitrogen showed a minimal dependence on the nitrogen-to-phosphorus (N/P) ratio, while the phosphorus removal efficiency showed a remarkable dependence on this parameter, increasing from 45 to 94.1% upon the increase of N/P ratio from 3 to 4.5. The increase of TN loading rate had a minimal impact on COD removal rate which remained around 1.7 kg/m(3) d, while it contributed to increased TP removal efficiency. The treatment of hog waste with influent COD, TN and TP concentrations of 960-2,400, 143-235 and 25-57 mg/L, respectively, produced removal efficiencies up to 89.2, 69.2 and 47.6% for the three contaminants, despite the inhibitory effects of this waste towards biological activity. The treatment system produced low biomass yields with average values of 3.7 and 8.2% during the treatment of synthetic wastewater and hog waste, respectively.

Removal of organic pollutants from produced water using Fenton oxidation

NASA Astrophysics Data System (ADS)

Afzal, Talia; Hasnain Isa, Mohamed; Mustafa, Muhammad Raza ul

2018-03-01

Produced water (PW) is the largest stream of wastewater from oil and gas exploration. It is highly polluted and requires proper treatment before disposal. The main objective of this study was to investigate the effectiveness of Fenton oxidation in degradation of organic matter in PW. The role of operating factors viz., H2O2 concentration (0.12 × 10-3 moles/L to 3 moles/L), [H2O2]/[Fe2+] molar ratio (2 to 75), and reaction time (30 to 200 minutes), on COD removal was determined through a series of batch experiments conducted in acidic environment at room temperature. The experiments were conducted with 500 mL PW samples in 1L glass beakers covered on the outside with aluminum foil to protect them from sunlight. Pre-decided amounts of ferrous sulfate heptahydrate (FeSO4.7H2O) and hydrogen peroxide (H2O2) were added to initiate the Fenton reaction. An increase in COD removal was observed with increase in reaction time and [H2O2]/[Fe2+] molar ratio. COD removal also increased with H2O2 concentration up to 0.01 moles/L; further increase in H2O2 concentration decreased the COD removal efficiency. Over 90% COD removal was achieved under optimum reaction conditions. The study indicates that Fenton oxidation is effective for remediation of PW in terms of organic matter removal.

Preparation of Bamboo Chars and Bamboo Activated Carbons to Remove Color and COD from Ink Wastewater.

PubMed

Hata, Motohide; Amano, Yoshimasa; Thiravetyan, Paitip; Machida, Motoi

2016-01-01

Bamboo chars and bamboo activated carbons prepared by steam activation were applied for ink wastewater treatment. Bamboo char at 800 °C was the best for the removal of color and chemical oxygen demand (COD) from ink wastewater compared to bamboo chars at 300 to 700 °C due to higher surface area and mesopore volume. Bamboo activated carbon at 600 °C (S600) was the best compared to bamboo activated carbon at 800 °C (S800), although S800 had larger surface area (1108 m(2)/g) than S600 (734 m(2)/g). S600 had higher mesopore volume (0.20 cm(3)/g) than S800 (0.16 cm(3)/g) and therefore achieved higher color and COD removal. All bamboo activated carbons showed higher color and COD removal efficiency than commercial activated carbon. In addition, S600 had the superior adsorption capacity for methylene blue (0.89 mmol/g). Therefore, bamboo is a suitable material to prepare adsorbents for removal of organic pollutants.

Effect of organic matter strength on anammox for modified greenhouse turtle breeding wastewater treatment.

PubMed

Chen, Chongjun; Huang, Xiaoxiao; Lei, Chenxiao; Zhang, Tian C; Wu, Weixiang

2013-11-01

Anaerobic ammonium-N removal from modified greenhouse turtle breeding wastewater with different chemical oxygen demand (COD) strengths (194.0-577.8 mg L(-1)) at relatively fixed C/N ratios (≈ 2) was investigated using a lab-scale up-flow anaerobic sludge blanket (UASB) anammox reactor. During the entire experiment, the total nitrogen (TN) removal efficiency was about 85% or higher, while the average COD removal efficiency was around 56.5 ± 7.9%. Based on the nitrogen and carbon balance, the nitrogen removal contribution was 79.6 ± 4.2% for anammox, 12.7 ± 3.0% for denitrification+denitritation and 7.7 ± 4.9% for other mechanisms. Denaturing gradient gel electrophoresis (DGGE) analyses revealed that Planctomycete, Proteobacteria and Chloroflexi bacteria were coexisted in the reactor. Anammox was always dominant when the reactor was fed with different COD concentrations, which indicated the stability of the anammox process with the coexistence of the denitrification process in treating greenhouse turtle breeding wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Treatment of leachate by electrocoagulation using aluminum and iron electrodes.

PubMed

Ilhan, Fatih; Kurt, Ugur; Apaydin, Omer; Gonullu, M Talha

2008-06-15

In this paper, treatment of leachate by electrocoagulation (EC) has been investigated in a batch process. The sample of leachate was supplied from Odayeri Landfill Site in Istanbul. Firstly, EC was compared with classical chemical coagulation (CC) process via COD removal. The first comparison results with 348 A/m2 current density showed that EC process has higher treatment performance than CC process. Secondly, effects of process variables such as electrode material, current density (from 348 to 631 A/m2), pH, treatment cost, and operating time for EC process are investigated on COD and NH4-N removal efficiencies. The appropriate electrode type search for EC provided that aluminum supplies more COD removal (56%) than iron electrode (35%) at the end of the 30 min operating time. Finally, EC experiments were also continued to determine the efficiency of ammonia removal, and the effects of current density, mixing, and aeration. All the findings of the study revealed that treatment of leachate by EC can be used as a step of a joint treatment.

Azo dyes wastewater treatment and simultaneous electricity generation in a novel process of electrolysis cell combined with microbial fuel cell.

PubMed

Zou, Haiming; Wang, Yan

2017-07-01

A new process of electrolysis cell (EC) coupled with microbial fuel cell (MFC) was developed here and its feasibility in methyl red (MR) wastewater treatment and simultaneous electricity generation was assessed. Results indicate that an excellent MR removal and electricity production performance was achieved, where the decolorization and COD removal efficiencies were 100% and 89.3%, respectively and a 0.56V of cell voltage output was generated. Electrolysis voltage showed a positive influence on decolorization rate (DR) but also cause a rapid decrease in current efficiency (CE). Although a low COD removal rate of 38.5% was found in EC system, biodegradability of MR solution was significantly enhanced, where the averaged DR was 85.6%. Importantly, COD removal rate in EC-MFC integrated process had a 50.8% improvement compared with the single EC system. The results obtained here would be beneficial to provide a prospective alternative for azo dyes wastewater treatment and power production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Conventional and thermophilic aerobic treatability of high strength oily pet food wastewater using membrane-coupled bioreactors.

PubMed

Kurian, R; Acharya, C; Nakhla, G; Bassi, A

2005-11-01

Although thermophilic treatment systems have recently gained considerable interest, limited information exists on the comparative performances of membrane-coupled bioreactors (MBR) at thermophilic and conventional conditions. In this study aerobic MBRs operating at room temperature (20 degrees C) and at lower thermophilic range (45 degrees C) were investigated for the treatment of dissolved air flotation (DAF) pretreated pet food wastewater. The particular wastewater is characterized by oil and grease (O & G) concentrations as high as 6 g/L, COD of 51 g/L, BOD of 16 g/L and volatile fatty acid (VFA) of 8.3 g/L. The performances of the two systems in terms of COD, BOD and O & G removal at varying hydraulic retention time (HRT) are compared. COD removal efficiencies in the thermophilic MBR varied from 75% to 98% and remained constant at 94% in the conventional MBR. The O & G removal efficiencies were 66-86% and 98% in the thermophilic and conventional MBR, respectively. Interestingly, high concentrations of VFA were recorded, equivalent to 50-73% of total COD, in the thermophilic MBR effluent. The observed yield in the thermophilic MBR was 40% of that observed in the conventional MBR.

Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands.

PubMed

Rossmann, Maike; Matos, Antonio Teixeira; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca; Borges, Alisson Carraro

2013-10-15

The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of Fenton and ozone-based advanced oxidation processes as mature landfill leachate pre-treatments.

PubMed

Cortez, Susana; Teixeira, Pilar; Oliveira, Rosário; Mota, Manuel

2011-03-01

Fenton treatment (Fe(2+)/H(2)O(2)) and different ozone-based Advanced Oxidation Processes (AOPs) (O(3), O(3)/OH(-) and O(3)/H(2)O(2)) were evaluated as pre-treatment of a mature landfill leachate, in order to improve the biodegradability of its recalcitrant organic matter for subsequent biological treatment. With a two-fold diluted leachate, at optimised experimental conditions (initial pH 3, H(2)O(2) to Fe(2+) molar ratio of 3, Fe(2+) dosage of 4 mmol L(-1), and reaction time of 40 min) Fenton treatment removed about 46% of chemical oxygen demand (COD) and increased the five-day biochemical oxygen demand (BOD(5)) to COD ratio (BOD(5)/COD) from 0.01 to 0.15. The highest removal efficiency and biodegradability was achieved by ozone at higher pH values, solely or combined with H(2)O(2). These results confirm the enhanced production of hydroxyl radical under such conditions. After the application for 60 min of ozone at 5.6 g O(3)h(-1), initial pH 7, and 400 mg L(-1) of hydrogen peroxide, COD removal efficiency was 72% and BOD(5)/COD increased from 0.01 to 0.24. An estimation of the operating costs of the AOPs processes investigated revealed that Fe(2+)/H(2)O(2) was the most economical system (8.2 € m(-3)g(-1) of COD removed) to treat the landfill leachate. This economic study, however, should be treated with caution since it does not consider the initial investment, prices at plant scale, maintenance and labour costs. Copyright © 2010 Elsevier Ltd. All rights reserved.

Role of algal biofilm in improving the performance of free surface, up-flow constructed wetland.

PubMed

Badhe, Neha; Saha, Shaswati; Biswas, Rima; Nandy, Tapas

2014-10-01

The role of algal biofilm in a pilot-scale, free-surface, up-flow constructed wetland (CW), was studied for its effect on chemical oxygen demand (COD), ammonia and phosphate removal during three seasons-autumn, winter and early spring. Effect of hydraulic retention time (HRT) was also investigated in presence and absence of algal biofilm. Principal Component Analysis was used to identify the independent factors governing the performance of CW. The study showed algal biofilm significantly improved nutrient removal, especially phosphate. Ammonia removal varied with HRT, biofilm and ambient temperature. Increase in biofilm thickness affected ammonia removal efficiency adversely. Algal biofilm-assisted COD removal compensated for reduced macrophyte density during winter. Two-way ANOVA test and the coefficients of dependent factors derived through multiple linear regression model confirmed role of algal biofilm in improving nutrient removal in CW. The study suggests that algal biofilm can be a green solution for bio-augmenting COD and nutrient removal in CW. Copyright © 2014 Elsevier Ltd. All rights reserved.

A combined electrochemical-irradiation treatment of highly colored and polluted industrial wastewater

NASA Astrophysics Data System (ADS)

Barrera-Díaz, C.; Ureña-Nuñez, F.; Campos, E.; Palomar-Pardavé, M.; Romero-Romo, M.

2003-07-01

This study reports on the attainment of optimal conditions for two electrolytic methods to treat wastewater: namely, electrocoagulation and particle destabilization of a highly polluted industrial wastewater, and electrochemically induced oxidation induced by in situ generation of Fenton's reactive. Additionally, a combined method that consisted of electrochemical treatment plus γ-irradiation was carried out. A typical composition of the industrial effluent treated was COD 3400 mg/l, color 3750 Pt/Co units, and fecal coliforms 21000 MPN/ml. The best removal efficiency was obtained with electrochemical oxidation induced in situ , that resulted in the reduction of 78% for the COD, 86% color and 99.9% fecal coliforms removal. A treatment sequence was designed and carried out, such that after both electrochemical processes, a γ-irradiation technique was used to complete the procedure. The samples were irradiated with various doses in an ALC γ-cell unit provided with a Co-60 source. The removal efficiency obtained was 95% for the COD values, 90% color and 99.9% for fecal coliforms.

Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter.

PubMed

Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M

2009-10-15

The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

Influence of chlorothalonil on the removal of organic matter in horizontal subsurface flow constructed wetlands.

PubMed

Casas-Zapata, Juan C; Ríos, Karina; Florville-Alejandre, Tomás R; Morató, Jordi; Peñuela, Gustavo

2013-01-01

This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT.

Laboratory septic tank performance response to electrolytic stimulation.

PubMed

Zaveri, Rahul M; Flora, Joseph R V

2002-11-01

This research investigated the effects of electrolytic stimulation on the performance of two laboratory-scale septic tanks. The tanks were fed a synthetic solution that included cellulose, peptone trypticase, beef extract, and urea. After a baseline period with no passed current, currents ranging from 100 to 500 mA were passed through the electrodes. The chemical oxygen demand (COD) removal efficiency from the tanks improved when a current was passed, with higher removal efficiencies observed at higher levels of passed current. Hydrolytic reactions resulted in ammonia and phosphate levels in the tanks that were higher than the influent. At currents > 300 mA, these hydrolytic reactions were suppressed, resulting in phosphate levels similar to the influent and ammonia levels lower than the influent because of the settling of ammonia-containing components of the feed solution. A slight increase in nitrate levels was observed when a current was passed, indicating minimal stimulation of nitrification activity. Abiotic studies confirmed that the COD can be removed via electrolysis and the removal was proportional to the passed current. Under the conditions of this study, the primary benefit of electrolytic stimulation of the septic tank is enhanced COD removal.

Treatment of coal gasification wastewater by membrane bioreactor hybrid powdered activated carbon (MBR–PAC) system.

PubMed

Jia, Shengyong; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng; Fang, Fang; Zhao, Qian

2014-12-01

A laboratory-scale membrane bioreactor hybrid powdered activated carbon (MBR–PAC) system was developed to treat coal gasification wastewater to enhance the COD, total phenols (TPh), NH4+ removals and migrate the membrane fouling. Since the MBR–PAC system operated with PAC dosage of 4 g L−1, the maximum removal efficiencies of COD, TPh and NH4+ reached 93%, 99% and 63%, respectively with the corresponding influent concentrations of 2.27 g L−1, 497 mg L−1 and 164 mg N L−1; the PAC extraction efficiencies of COD, TPh and NH4+ were 6%, 3% and 13%, respectively; the transmembrane pressure decreased 34% with PAC after 50 d operation. The results demonstrate that PAC played a key role in the enhancement of biodegradability and mitigation of membrane fouling.

Performance of CSTR-EGSB-SBR system for treating sulfate-rich cellulosic ethanol wastewater and microbial community analysis.

PubMed

Shan, Lili; Zhang, Zhaohan; Yu, Yanling; Ambuchi, John Justo; Feng, Yujie

2017-06-01

Performance and microbial community composition were evaluated in a two-phase anaerobic and aerobic system treating sulfate-rich cellulosic ethanol wastewater (CEW). The system was operated at five different chemical oxygen demand (COD)/SO 4 2- ratios (63.8, 26.3, 17.8, 13.7, and 10.7). Stable performance was obtained for total COD removal efficiency (94.5%), sulfate removal (89.3%), and methane production rate (11.5 L/day) at an organic loading rate of 32.4 kg COD/(m 3 ·day). The acidogenic reactor made a positive contribution to net VFAs production (2318.1 mg/L) and sulfate removal (60.9%). Acidogenic bacteria (Megasphaera, Parabacteroides, unclassified Ruminococcaceae spp., and Prevotella) and sulfate-reducing bacteria (Butyrivibrio, Megasphaera) were rich in the acidogenic reactor. In the methanogenic reactor, high diversity of microorganisms corresponded with a COD removal contribution of 83.2%. Moreover, methanogens (Methanosaeta) were predominant, suggesting that these organisms played an important role in the acetotrophic methanogenesis pathway. The dominant aerobic bacteria (Truepera) appeared to have been responsible for the COD removal of the SBR. These results indicate that dividing the sulfate reduction process could effectively minimize sulfide toxicity, which is important for the successful operation of system treating sulfate-rich CEW.

Nitrogen removal from wastewater and bacterial diversity in activated sludge at different COD/N ratios and dissolved oxygen concentrations.

PubMed

Zielińska, Magdalena; Bernat, Katarzyna; Cydzik-Kwiatkowska, Agnieszka; Sobolewska, Joanna; Wojnowska-Baryła, Irena

2012-01-01

The impact of the organic carbon to nitrogen ratio (chemical oxygen demand (COD)/N) in wastewater and dissolved oxygen (DO) concentration on carbon and nitrogen removal efficiency, and total bacteria and ammonia-oxidizing bacteria (AOB) communities in activated sludge in constantly aerated sequencing batch reactors (SBRs) was determined. At DO of 0.5 and 1.5 mg O2/L during the aeration phase, the efficiency of ammonia oxidation exceeded 90%, with nitrates as the main product. Nitrification and denitrification achieved under the same operating conditions suggested the simultaneous course of these processes. The most effective nitrogen elimination (above 50%) was obtained at the COD/N ratio of 6.8 and DO of 0.5 mg O2/L. Total bacterial diversity was similar in all experimental series, however, for both COD/N ratios of 6.8 and 0.7, higher values were observed at DO of 0.5 mg O2/L. The diversity and abundance of AOB were higher in the reactors with the COD/N ratio of 0.7 in comparison with the reactors with the COD/N of 6.8. For both COD/N ratios applied, the AOB population was not affected by oxygen concentration. Amplicons with sequences indicating membership of the genus Nitrosospira were the determinants of variable technological conditions.

Coupling biofiltration process and electrocoagulation using magnesium-based anode for the treatment of landfill leachate.

PubMed

Oumar, Dia; Patrick, Drogui; Gerardo, Buelna; Rino, Dubé; Ihsen, Ben Salah

2016-10-01

In this research paper, a combination of biofiltration (BF) and electrocoagulation (EC) processes was used for the treatment of sanitary landfill leachate. Landfill leachate is often characterized by the presence of refractory organic compounds (BOD/COD < 0.13). BF process was used as secondary treatment to remove effectively ammonia nitrogen (N-NH4 removal of 94%), BOD (94% removed), turbidity (95% removed) and phosphorus (more than 98% removed). Subsequently, EC process using magnesium-based anode was used as tertiary treatment. The best performances of COD and color removal from landfill leachate were obtained by applying a current density of 10 mA/cm(2) through 30 min of treatment. The COD removal reached 53%, whereas 85% of color removal was recorded. It has been proved that the alkalinity had a negative effect on COD removal during EC treatment. COD removal efficiencies of 52%, 41% and 27% were recorded in the presence of 1.0, 2.0 and 3.0 g/L of sodium bicarbonate (NaHCO3), respectively. Hydroxide ions produced at the cathode electrode reacted with the bicarbonate ions to form carbonates. The presence of bicarbonates in solution hampered the increase in pH, so that the precipitation of magnesium hydroxides could not take place to effectively remove organic pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biological treatment of wastewaters from a dye manufacturing company using a trickling filter.

PubMed

Kornaros, M; Lyberatos, G

2006-08-10

The aim of this work was to assess the effectiveness of a biological trickling filter for the treatment of wastewaters produced by a company manufacturing organic dyes and varnishes. The combined wastewater effluent was fed to a pilot-scale trickling filter in two feeding modes, continuously and as a sequencing batch reactor (SBR). The biodegradability of the diluted wastewaters that were subjected to physicochemical treatment, using Ca(OH)(2) and FeSO(4), was initially studied using a continuously operated trickling filter. The system efficiency ranged up to 60-70% for a hydraulic loading of 1.1 m(3)/m(2)day and up to 80-85% for a hydraulic loading 0.6 m(3)/m(2)day. A stable chemical oxygen demand (COD) removal efficiency of 60-70% was achieved even in the case of undiluted wastewater at a hydraulic loading of 1.1 m(3)/m(2)day. The effectiveness of biological treatment of a mixture of the company's main wastewater streams was also examined. The microorganisms developed in the trickling filter were able to efficiently remove COD levels up to 36,000 mg/L, under aerobic conditions at pH values between 5.5 and 8.0. Depending on the operating conditions of the system, about 30-60% of the total COD removal was attributed to air stripping caused by the air supply at the bottom of the filter, whereas the rest of the COD was clearly removed through biological action. The proposed biological treatment process based on a trickling filter, which was operated either continuously or even better in an SBR mode, appears as a promising pretreatment step for coping with dye manufacturing wastewaters in terms of removing a significant portion of the organic content.

Effect of COD/SO4(2-) ratio on anaerobic treatment of landfill leachate during the start-up period.

PubMed

Yilmaz, Tuba; Erdirencelebi, Dilek; Berktay, Ali

2012-01-01

This study investigates the performance of an anaerobic baffled reactor (ABR) during the start-up period of raw young landfill leachate treatment at two chemical oxygen demand (COD) to SO4(2-) ratios of 20 and 4. The reactor was operated at ambient temperature and low organic loading rates (0.52, 0.76 and 1.05 kg COD/m3 per day). During the study, sulfate-reducing bacteria (SRB) activity increased at the lower ratio of COD/SO4(2-) producing higher levels of sulfide and alkalinity. The dissolved sulfide concentration reached an inhibitory level above 250 mg/L, which caused a sharp reduction in the total COD removal efficiency from 77-80% to 32%. Total volatile fatty acid (TVFA) production proceeded at a constant level despite increased organic loading. As the effluent total and organic COD concentrations increased, the inhibitory effect of the inborn sulfide was correlated to the limitation experienced in the hydrolysis/acidogenesis stages, and thus VFA production and organic matter removal.

Floating treatment wetlands for domestic wastewater treatment.

PubMed

Faulwetter, J L; Burr, M D; Cunningham, A B; Stewart, F M; Camper, A K; Stein, O R

2011-01-01

Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ∼50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment.

Biodegradation of potato slops from a rural distillery by thermophilic aerobic bacteria.

PubMed

Cibis, Edmund; Kent, Christopher A; Krzywonos, Malgorzata; Garncarek, Zbigniew; Garncarek, Barbara; Miśkiewicz, Tadeusz

2002-10-01

A study has been made of thermophilic aerobic biodegradation of the liquid fraction of potato slops (distillation residue) from a rural distillery. The COD of this fraction ranged from 49 to 104 g O2/l, the main contributions to the COD coming from organic acids, reducing substances, and glycerol. It was found that biodegradation could be divided into the following stages: organic acids were removed first, followed by reducing substances and glycerol. The extent of removal varied according to the process temperature. At 50 degrees C, acetic and malic acids were removed completely, but the amount of isobutyric acid increased. At 60 degrees C, organic acid removal ranged from 51.2% (isobutyric acid) to 99.6% (lactic acid). Removals of glycerol and reducing substances were 86.2% and 87.4%, respectively. COD reduction was also temperature dependent, the highest removal efficiency (76.7%) being achieved at 60 degrees C. Dissolved oxygen may have limited the biodegradation process, as indicated by the DOT-versus-time profile.

Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.

PubMed

Luostarinen, S; Rintala, J

2006-01-01

Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10-20 degrees C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 degrees C. Removal of total chemical oxygen demand (COD1) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperature decrease had little effect on COD removals, though the need for phase 2 increased with decreasing temperature, especially with BWKW. Post-treatment of BWKW in MBBR resulted in approx. 50% nitrogen removal, but suffered from lack of carbon for denitrification. With carbon addition, removal of ca. 83% was achieved.

Comparison of coagulation, ozone and ferrate treatment processes for color, COD and toxicity removal from complex textile wastewater.

PubMed

Malik, Sameena N; Ghosh, Prakash C; Vaidya, Atul N; Waindeskar, Vishal; Das, Sera; Mudliar, Sandeep N

2017-09-01

In this study, the comparative performance of coagulation, ozone, coagulation + ozone + coagulation and potassium ferrate processes to remove chemical oxygen demand (COD), color, and toxicity from a highly polluted textile wastewater were evaluated. Experimental results showed that ferrate alone had no effect on COD, color and toxicity removal. Whereas, in combination with FeSO 4 , it has shown the highest removal efficiency of 96.5%, 83% and 75% for respective parameters at the optimal dose of 40 mgL -1 + 3 ml FeSO 4 (1 M) in comparison with other processes. A seed germination test using seeds of Spinach (Spinacia oleracea) also indicated that ferrate was more effective in removing toxicity from contaminated textile wastewater. Potassium ferrate also produces less sludge with maximum contaminant removal, thereby making the process more economically feasible. Fourier transform infrared spectroscopy (FTIR) analysis also shows the cleavage of the chromophore group and degradation of textile wastewater during chemical and oxidation treatment processes.

Nutrients removal from undiluted cattle farm wastewater by the two-stage process of microalgae-based wastewater treatment.

PubMed

Lv, Junping; Liu, Yang; Feng, Jia; Liu, Qi; Nan, Fangru; Xie, Shulian

2018-05-24

Chlorella vulgaris was selected from five freshwater microalgal strains of Chlorophyta, and showed a good potential in nutrients removal from undiluted cattle farm wastewater. By the end of treatment, 62.30%, 81.16% and 85.29% of chemical oxygen demand (COD), ammonium (NH 4 + -N) and total phosphorus (TP) were removed. Then two two-stage processes were established to enhance nutrients removal efficiency for meeting the discharge standards of China. The process A was the biological treatment via C. vulgaris followed by the biological treatment via C. vulgaris, and the process B was the biological treatment via C. vulgaris followed by the activated carbon adsorption. After 3-5 d of treatment of wastewater via the two processes, the nutrients removal efficiency of COD, NH 4 + -N and TP were 91.24%-92.17%, 83.16%-94.27% and 90.98%-94.41%, respectively. The integrated two-stage process could strengthen nutrients removal efficiency from undiluted cattle farm wastewater with high organic substance and nitrogen concentration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Application of a membrane bioreactor for winery wastewater treatment.

PubMed

Bolzonella, D; Fatone, F; Pavan, P; Cecchi, F

2010-01-01

Winery wastewaters are variable in nature and are hard to treat by means of the conventional activated sludge process because of the high organic loading associated with their production, especially during vintage. To face this situation, recently, membrane bioreactors have been widely applied to treat winery wastewaters. In this study, a full-scale membrane bioreactor treated some 110 m(3)/d of wastewater and organic loadings up to 1,600 kg COD per day. The average removal efficiency was 95% while the corresponding sludge yield was only 0.1 kg MLVSS per kg COD removed, as usual for these wastewaters. A detailed analysis of energy consumption showed specific energy demands of 2.0-3.6 kWh/m(3) of treated wastewater or 1 kWh per kg of COD removed.

The use of waterworks sludge for the treatment of vegetable oil refinery industry wastewater.

PubMed

Basibuyuk, M; Kalat, D G

2004-03-01

Water treatment works using coagulation/flocculation in the process stream will generate a waste sludge. This sludge is termed as ferric, alum, or lime sludge based on which coagulant was primarily used. The works in Adana, Turkey uses ferric chloride. The potential for using this sludge for the treatment of vegetable oil refinery industry wastewater by coagulation has been investigated. The sludge acted as a coagulant and excellent oil and grease, COD and TSS removal efficiencies were obtained. The optimum conditions were a pH of 6 and a sludge dose of 1100 mg SS l(-1). The efficiency of sludge was also compared with alum and ferric chloride for the vegetable oil refinery wastewater. At doses of 1300-1900 mg SS l(-1), the sludge was as effective as ferric chloride and alum at removing oil and grease, COD, and TSS. In addition, various combinations of ferric chloride and waterworks sludge were also examined. Under the condition of 12.5 mg l(-1) fresh ferric chloride and 1000 mg SS l(-1) sludge dose, 99% oil and grease 99% TSS and 83% COD removal efficiencies were obtained.

Study of the efficiency of moving bed biofilm reactor (MBBR) in LAS Anionic Detergent removal from hospital wastewater: determination of removing model according to response surface methodology (RSM).

PubMed

Shokoohi, Reza; Torkshavand, Zahra; Zolghadnasab, Hassan; Alikhani, Mohammad Yousef; Hemmat, Meisam Sedighi

2017-04-01

Detergents are considered one of the important pollutants in hospital wastewater. Achieving efficient and bio-friendly methods for the removal of these pollutants is considered as a concern for environmental researchers. This study aims at studying the efficiency of a moving bed biofilm reactor (MBBR) system for removing linear alkyl benzene sulfonate (LAS) from hospital wastewater with utilization of response surface methodology (RSM). The present study was carried out on a reactor with continuous hydraulic flow using media k 1 at pilot scale to remove detergent from hospital wastewater. The effect of independent variables including contact time, percentage of media filling and mixed liquor suspended solids (MLSS) concentration of 1000-3000 mg/l on the system efficiency were assessed. Methylene blue active substances (MBAS) and chemical oxygen demand (COD) 750-850 mg/l were used by closed laboratory method in order to measure the concentration of LAS. The results revealed that the removal efficiency of LAS detergent and COD using media k 1 , retention time of 24 hours, and MLSS concentration of around 3,000 mg/l were 92.3 and 95.8%, respectively. The results showed that the MBBR system as a bio-friendly compatible method has high efficiency in removing detergents from hospital wastewater and can achieve standard output effluent in acceptable time.

Evaluating photo-degradation of COD and TOC in petroleum refinery wastewater by using TiO2/ZnO photo-catalyst.

PubMed

Aljuboury, Dheeaa Al Deen Atallah; Palaniandy, Puganeshwary; Abdul Aziz, Hamidi Bin; Feroz, Shaik; Abu Amr, Salem S

2016-09-01

The aim of this study is to investigate the performance of combined solar photo-catalyst of titanium oxide/zinc oxide (TiO 2 /ZnO) with aeration processes to treat petroleum wastewater. Central composite design with response surface methodology was used to evaluate the relationships between operating variables for TiO 2 dosage, ZnO dosage, air flow, pH, and reaction time to identify the optimum operating conditions. Quadratic models for chemical oxygen demand (COD) and total organic carbon (TOC) removals prove to be significant with low probabilities (<0.0001). The obtained optimum conditions included a reaction time of 170 min, TiO 2 dosage (0.5 g/L), ZnO dosage (0.54 g/L), air flow (4.3 L/min), and pH 6.8 COD and TOC removal rates of 99% and 74%, respectively. The TOC and COD removal rates correspond well with the predicted models. The maximum removal rate for TOC and COD was 99.3% and 76%, respectively at optimum operational conditions of TiO 2 dosage (0.5 g/L), ZnO dosage (0.54 g/L), air flow (4.3 L/min), reaction time (170 min) and pH (6.8). The new treatment process achieved higher degradation efficiencies for TOC and COD and reduced the treatment time comparing with other related processes.

Treatment of soil eluate containing nitro aromatic compounds by adsorption on activated coke (AC).

PubMed

Zhang, Yiping; Jiang, Zhenming; Zhao, Quanlin; Zhang, Zhenzhong; Su, Hongping; Gao, Xuewen; Ye, Zhengfang

2016-01-01

Soil washing is a kind of physical method to remove organic matters from contaminated soil. However, its eluate after washing may result in secondary pollution to the environment. In this study, activated coke (AC) was used to remove organic pollutants from contaminated soil eluate. The effect of temperature, initial chemical oxygen demand (COD) and AC dosage on COD removal efficiency was investigated. The results showed that the organic matter can be removed in the eluate because the COD dropped a lot. When the AC dosage was 20 g·L(-1), 88.92% of COD decreased after 480 min of adsorption at 50 °C. The process of adsorption can be described by the Redlich-Peterson isotherm. The adsorption was spontaneous and endothermic. The pseudo-second-order model can be used to describe the adsorption process. After adsorption, the acute toxicity of the eluate was reduced by 76%, and the water qualities were in agreement with Chinese discharge standard GB 14470.1-2002, which means the eluate could be discharged to the environment.

Evaluating the efficiency of carbon utilisation via bioenergetics between biological aerobic and denitrifying phosphorus removal systems

PubMed Central

Jin, Zhan; He, Yin; Xu, Xuan; Zheng, Xiang-yong

2017-01-01

There are two biological systems available for removing phosphorus from waste water, conventional phosphorus removal (CPR) and denitrifying phosphorus removal (DPR) systems, and each is characterized by the type of sludge used in the process. In this study, we compared the characteristics associated with the efficiency of carbon utilization between CPR and DPR sludge using acetate as a carbon source. For DPR sludge, the heat emitted during the phosphorus release and phosphorus uptake processes were 45.79 kJ/mol e- and 84.09 kJ/mol e-, respectively. These values were about 2 fold higher than the corresponding values obtained for CPR sludge, suggesting that much of the energy obtained from the carbon source was emitted as heat. Further study revealed a smaller microbial mass within the DPR sludge compared to CPR sludge, as shown by a lower sludge yield coefficient (0.05 gVSS/g COD versus 0.36 gVSS/g COD), a result that was due to the lower energy capturing efficiency of DPR sludge according to bioenergetic analysis. Although the efficiency of anoxic phosphorus removal was only 39% the efficiency of aerobic phosphorus removal, the consumption of carbon by DPR sludge was reduced by 27.8% compared to CPR sludge through the coupling of denitrification with dephosphatation. PMID:29065157

Combined process of electrocoagulation and photocatalytic degradation for the treatment of olive washing wastewater.

PubMed

Ates, Hasan; Dizge, Nadir; Yatmaz, H Cengiz

2017-01-01

In this study, an electrocoagulation reactor (ECR) and photocatalytic reactor (PCR) were tested to understand the performance of combined electrocoagulation and photocatalytic-degradation of olive washing wastewater (OWW). The effects of initial pH (6.0, 6.9, 8.0, 9.0), applied voltage (10.0, 12.5, 15.0 V), and operating time (30, 60, 90, 120 min) were investigated in the electrocoagulation reactor when aluminum electrodes were used as both anode and cathode. The pH, conductivity, color, chemical oxygen demand (COD), and phenol were measured versus time to determine the efficiency of the ECR and PCR process. It was observed that electrocoagulation as a single treatment process supplied the COD removal of 62.5%, color removal of 98.1%, and total phenol removal of 87% at optimum conditions as pH 6.9, applied voltage of 12.5 V, and operating time of 120 min. Moreover, final pH and conductivity were 7.7 and 980 μS/cm, respectively. On the other hand, the effect of semiconductor catalyst type (TiO 2 and ZnO) and loading (1, 2, 3 g/L) were tested using PCR as a stand-alone technique. It was found that photocatalytic degradation as a single treatment process when using 1 g/L ZnO achieved the COD removal of 46%, color removal of 99% with a total phenol removal of 41% at optimum conditions. Final pH and conductivity were 6.2 and 915 μS/cm, respectively. Among semiconductor catalysts, TiO 2 and ZnO performed identical efficiencies for both COD and total phenol removal. Moreover, combination in which electrochemical degradation was employed as a pre-treatment to the photocatalytic degradation process obtained high COD removal of 88% and total phenol, as well as color removal of 100% for the OWW. The electrochemical treatment alone was not effective, but in combination with the photocatalytic process, led to a high-quality effluent. Finally, sludge collected from the electrocoagulation process was characterized by attenuated total reflection Fourier transform infrared and X-ray powder diffraction analyses.

Utilization of moving bed biofilm reactor for industrial wastewater treatment containing ethylene glycol: kinetic and performance study.

PubMed

Hassani, Amir Hessam; Borghei, Seyed Mehdi; Samadyar, Hassan; Ghanbari, Bastam

2014-01-01

One of the requirements for environmental engineering, which is currently being considered, is the removal of ethylene glycol (EG) as a hazardous environmental pollutant from industrial wastewater. Therefore, in a recent study, a moving bed biofilm reactor (MBBR) was applied at pilot scale to treat industrial effluents containing different concentrations of EG (600, 800, 1200, and 1800 mg L-1 ). The removal efficiency and kinetic analysis of the system were examined at different hydraulic retention times of 6, 8, 10, and 12 h as well as influent chemical oxygen demand (COD) ranged between values of 1000 and 3000mg L-1. In minimum and maximum COD Loadings, the MBBR showed 95.1% and 60.7% removal efficiencies, while 95.9% and 66.2% EG removal efficiencies were achieved in the lowest and highest EG concentrations. The results of the reactor modelling suggested compliance of the well-known modified Stover-Kincannon model with the system.

Mechanism of Electro-Coagulation with Al/Fe Periodically Reversing Treating Berberine Pharmaceutical Wastewater

NASA Astrophysics Data System (ADS)

Sun, Zhaonan; Liu, Zheng; Hu, Xiaomin

2017-05-01

The method of treating pharmaceutical wastewater by electro-coagulation with Al/Fe periodically reversing (ECPR) was proposed based on traditional electrochemical method. The principle of ECPR was generalized. Mechanism of ECPR to treat berberine pharmaceutical wastewater was investigated. Treatability and mechanism studies were conducted under laboratory conditions. For berberine wastewater (800 mg/L), decolourization efficiency and COD removal efficiency were highest to 98% and 95% respectively when voltage was 8V, reaction time was 60 min, alternating period was 10 S electrolyte concentration was 0.015 mol/L, stirring speed was 750 rpm, pH value was 3-10 and distance between two plates was 0.6 cm. For removal berberine, flocculation, floatation and oxidation provided 73%, 8% and 18% removal efficiency, which can be inferred by analysing UV-visible absorption spectrum, acidification experiment, EDTA shielding experiment, structure-activity relationship, oxidation and floatation. Meanwhile decolourization and COD removal conformed to apparent pseudo-first order and zero-order kinetics for 200mg/L and 400-1000 mg/L berberine wastewater respectively.

Microbial communities in the functional areas of a biofilm reactor with anaerobic-aerobic process for oily wastewater treatment.

PubMed

Li, Jianhua; Sun, Shanshan; Yan, Ping; Fang, Li; Yu, Yang; Xiang, Yangdong; Wang, Di; Gong, Yejing; Gong, Yanjun; Zhang, Zhongzhi

2017-08-01

Microbial communities in the functional areas of biofilm reactors with large height-diameter ratio using the anaerobic-aerobic (A/O) reflux process was investigated to treat heavy oil refinery wastewater without pretreatment. In the process, chemical oxygen demand (COD) and total nitrogen (TN) removal reached 93.2% and 82.8%, and the anaerobic biofilm reactor was responsible for 95% and 99%, respectively. Areas for hydrolysis acidification and acetic acid production, methane production, and COD recovery were obvious in the anaerobic reactor. Among all areas, area for hydrolysis acidification and acetic acid production was the key factor to improve COD removal efficiency. High throughput sequencing of 16S rDNA gene showed that the native community was mainly composed of functional groups for hydrocarbon degradation, syntrophic bacteria union body, methanogenesis, nitrification, denitrification, and sulfate reduction. The deviations between predicted values and actual COD and TN removal were less than 5% in the optimal prediction model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Artificial intelligence based model for optimization of COD removal efficiency of an up-flow anaerobic sludge blanket reactor in the saline wastewater treatment.

PubMed

Picos-Benítez, Alain R; López-Hincapié, Juan D; Chávez-Ramírez, Abraham U; Rodríguez-García, Adrián

2017-03-01

The complex non-linear behavior presented in the biological treatment of wastewater requires an accurate model to predict the system performance. This study evaluates the effectiveness of an artificial intelligence (AI) model, based on the combination of artificial neural networks (ANNs) and genetic algorithms (GAs), to find the optimum performance of an up-flow anaerobic sludge blanket reactor (UASB) for saline wastewater treatment. Chemical oxygen demand (COD) removal was predicted using conductivity, organic loading rate (OLR) and temperature as input variables. The ANN model was built from experimental data and performance was assessed through the maximum mean absolute percentage error (= 9.226%) computed from the measured and model predicted values of the COD. Accordingly, the ANN model was used as a fitness function in a GA to find the best operational condition. In the worst case scenario (low energy requirements, high OLR usage and high salinity) this model guaranteed COD removal efficiency values above 70%. This result is consistent and was validated experimentally, confirming that this ANN-GA model can be used as a tool to achieve the best performance of a UASB reactor with the minimum requirement of energy for saline wastewater treatment.

Treatment of highly concentrated tannery wastewater using electrocoagulation: Influence of the quality of aluminium used for the electrode.

PubMed

Elabbas, S; Ouazzani, N; Mandi, L; Berrekhis, F; Perdicakis, M; Pontvianne, S; Pons, M-N; Lapicque, F; Leclerc, J-P

2016-12-05

This paper deals with the ability of electrocoagulation (EC) to remove simultaneously COD and chromium from a real chrome tanning wastewater in a batch stirred electro-coagulation cell provided with two aluminium-based electrodes (aluminium/copper/magnesium alloy and pure aluminium). Effects of operating time, current density and initial concentration of Cr(III) and COD have been investigated. The concentrations of pollutants have been successfully reduced to environmentally acceptable levels even if the concentrated effluent requires a long time of treatment of around 6h with a 400A/m(2) current density. The aluminium alloy was found to be more efficient than pure aluminium for removal of COD and chromium. Dilution of the waste has been tested for treatment: high abatement levels could be obtained with shorter time of treatment and lower current densities. Energy consumption of the electrocoagulation process was also discussed. The dilution by half of the concentrated waste leads to a higher abatement performance of both COD and chromium with the best energy efficiency. Copyright © 2016 Elsevier B.V. All rights reserved.

Treatment of a textile effluent by adsorption with cork granules and titanium dioxide nanomaterial.

PubMed

Castro, Margarida; Nogueira, Verónica; Lopes, Isabel; Vieira, Maria N; Rocha-Santos, Teresa; Pereira, Ruth

2018-05-12

This study aimed to explore the efficiency of two adsorbents, cork granules with different granulometry and titanium dioxide nanomaterial, in the removal of chemical oxygen demand (COD), colour and toxicity from a textile effluent. The adsorption assays with cork were unsatisfactory in the removal of chemical parameters however they eliminated the acute toxicity of the raw effluent to Daphnia magna. The assay with TiO 2 NM did not prove to be efficient in the removal of colour and COD even after 240 min of contact; nevertheless it also reduced the raw effluent toxicity. The best approach for complete remediation of the textile effluent has not yet been found however promising findings were achieved, which may be an asset in future adsorption assays.

Pulsed corona discharge for improving treatability of coking wastewater.

PubMed

Liu, Ming; Preis, Sergei; Kornev, Iakov; Hu, Yun; Wei, Chao-Hai

2018-02-01

Coking wastewater (CW) contains toxic and macromolecular substances that inhibit biological treatment. The refractory compounds remaining in biologically treated coking wastewater (BTCW) provide chemical oxygen demand (COD) and color levels that make it unacceptable for reuse or disposal. Gas-phase pulsed corona discharge (PCD) utilizing mostly hydroxyl radicals and ozone as oxidants was applied to both raw coking wastewater (RCW) and BTCW wastewater as a supplemental treatment. The energy efficiency of COD, phenol, thiocyanate and cyanide degradation by PCD was the subject of the research. The cost-effective removal of intermediate oxidation products with addition of lime was also studied. The energy efficiency of oxidation was inversely proportional to the pulse repetition frequency: lower frequency allows more effective utilization of ozone at longer treatment times. Oxidative treatment of RCW showed the removal of phenol and thiocyanate at 800 pulses per second from 611 to 227mg/L and from 348 to 86mg/L, respectively, at 42kWh/m 3 delivered energy, with substantial improvement in the BOD 5 /COD ratio (from 0.14 to 0.43). The COD and color of BTCW were removed by 30% and 93%, respectively, at 20kWh/m 3 , showing energy efficiency for the PCD treatment exceeding that of conventional ozonation by a factor of 3-4. Application of lime appeared to be an effective supplement to the PCD treatment of RCW, degrading COD by about 28% at an energy input of 28kWh/m 3 and the lime dose of 3.0kg/m 3 . The improvement of RCW treatability is attributed to the degradation of toxic substances and fragmentation of macromolecular compounds. Copyright © 2017. Published by Elsevier B.V.

An experimental model of COD abatement in MBBR based on biofilm growth dynamic and on substrates' removal kinetics.

PubMed

Siciliano, Alessio; De Rosa, Salvatore

2016-08-01

In this study, the performance of a lab-scale Moving Bed Biofilm Reactor (MBBR) under different operating conditions was analysed. Moreover, the dependence of the reaction rates both from the concentration and biodegradability of substrates and from the biofilm surface density, by means of several batch kinetic tests, was investigated. The reactor controls exhibited an increasing COD (Chemical Oxygen Demand) removal, reaching maximum yields (close to 90%) for influent loadings of up to12.5 gCOD/m(2)d. From this value, the pilot plant performance decreased to yields of only about 55% for influent loadings greater than 16 gCOD/m(2)d. In response to the influent loading increase, the biofilm surface density exhibited a logistic growing trend until reaching a maximum amount of total attached solids of about 9.5 g/m(2). The kinetic test results indicated that the COD removal rates for rapidly biodegradable, rapidly hydrolysable and slowly biodegradable substrates were not affected by the organic matter concentrations. Instead, first-order kinetics were detected with respect to biofilm surface density. The experimental results permitted the formulation of a mathematical model to predict the MBBR organic matter removal efficiency. The validity of the model was successfully tested in the lab-scale plant.

Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes.

PubMed

Zayas Pérez, Teresa; Geissler, Gunther; Hernandez, Fernando

2007-01-01

The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes (AOP) had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H2O2, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand (COD) and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater.

A novel pilot-scale stacked microbial fuel cell for efficient electricity generation and wastewater treatment.

PubMed

Wu, Shijia; Li, Hui; Zhou, Xuechen; Liang, Peng; Zhang, Xiaoyuan; Jiang, Yong; Huang, Xia

2016-07-01

A novel stacked microbial fuel cell (MFC) which had a total volume of 72 L with granular activated carbon (GAC) packed bed electrodes was constructed and verified to present remarkable power generation and COD removal performance due to its advantageous design of stack and electrode configuration. During the fed-batch operation period, a power density of 50.9 ± 1.7 W/m(3) and a COD removal efficiency of 97% were achieved within 48 h. Because of the differences among MFC modules in the stack, reversal current occurred in parallel circuit connection with high external resistances (>100 Ω). This reversal current consequently reduced the electrochemical performance of some MFC modules and led to a lower power density in parallel circuit connection than that in independent circuit connection. While increasing the influent COD concentrations from 200 to 800 mg/L at hydraulic retention time of 1.25 h in continuous operation mode, the power density of stacked MFC increased from 25.6 ± 2.5 to 42.1 ± 1.2 W/m(3) and the COD removal rates increased from 1.3 to 5.2 kg COD/(m(3) d). This study demonstrated that this novel MFC stack configuration coupling with GAC packed bed electrode could be a feasible strategy to effectively scale up MFC systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrochemical treatment of domestic wastewater using boron-doped diamond and nanostructured amorphous carbon electrodes.

PubMed

Daghrir, Rimeh; Drogui, Patrick; Tshibangu, Joel; Delegan, Nazar; El Khakani, My Ali

2014-05-01

The performance of the electrochemical oxidation process for efficient treatment of domestic wastewater loaded with organic matter was studied. The process was firstly evaluated in terms of its capability of producing an oxidant agent (H2O2) using amorphous carbon (or carbon felt) as cathode, whereas Ti/BDD electrode was used as anode. Relatively high concentrations of H2O2 (0.064 mM) was produced after 90 min of electrolysis time, at 4.0 A of current intensity and using amorphous carbon at the cathode. Factorial design and central composite design methodologies were successively used to define the optimal operating conditions to reach maximum removal of chemical oxygen demand (COD) and color. Current intensity and electrolysis time were found to influence the removal of COD and color. The contribution of current intensity on the removal of COD and color was around 59.1 and 58.8%, respectively, whereas the contribution of treatment time on the removal of COD and color was around 23.2 and 22.9%, respectively. The electrochemical treatment applied under 3.0 A of current intensity, during 120 min of electrolysis time and using Ti/BDD as anode, was found to be the optimal operating condition in terms of cost/effectiveness. Under these optimal conditions, the average removal rates of COD and color were 78.9 ± 2 and 85.5 ± 2 %, whereas 70% of total organic carbon removal was achieved.

Treatment of high salinity organic wastewater by membrane electrolysis

NASA Astrophysics Data System (ADS)

Dongfang, Shen; Jinghuan, Ma; Ying, Liu; Chenguang, Zhao

2018-03-01

The effects of different operating conditions on the treatment of electrolytic wastewater were investigated by analyzing the removal rate of ammonia and COD before and after wastewater treatment by cation exchange membrane. Experiment shows that as the running time increases the electrolysis effect first increases after the smooth. The removal rate of ammonia will increase with the increase of current density, and the removal rate of COD will increase first and then decrease with the increase of current density. The increase of the temperature of the electrolytic solution will slowly increase the COD removal rate to saturation, but does not affect the removal of ammonia nitrogen. When the flow rate is less than 60L / h, the change of influent flow rate will not affect the removal of ammonia nitrogen, but the effect on COD is small, which will increase and decrease slightly. After the experiment, the surface of the cation exchange membrane was analyzed by cold field scanning electron microscopy and X-ray energy dispersive spectrometer. The surface contamination and the pollutant were determined. The experimental results showed that the aggregates were mainly chlorinated Sodium, calcium and magnesium inorganic salts, which will change the morphology of the film to reduce porosity, reduce the mass transfer efficiency, affecting the electrolysis effect.

[Anaerobic membrane bioreactors for treating agricultural and food processing wastewater at high strength].

PubMed

Wei, Yuan-Song; Yu, Da-Wei; Cao, Lei

2014-04-01

As the second largest amounts of COD discharged in 41 kinds of industrial wastewater, it is of great urgency for the agricultural and food processing industry to control water pollution and reduce pollutants. Generally the agricultural and food processing industrial wastewater with high strength COD of 8 000-30 000 mg x L(-1), is mainly treated with anaerobic and aerobic processes in series, but which exists some issues of long process, difficult maintenance and high operational costs. Through coupling anaerobic digestion and membrane separation together, anaerobic membrane bioreactor (AnMBR) has typical advantages of high COD removal efficiency (92%-99%), high COD organic loading rate [2.3-19.8 kg x (m3 x d)(-1)], little sludge discharged (SRT > 40 d) and low cost (HRT of 8-12 h). According to COD composition of high strength industrial wastewater, rate-limiting step of methanation could be either hydrolysis and acidification or methanogenesis. Compared with aerobic membrane bioreactor (MBR), membrane fouling of AnMBR is more complicated in characterization and more difficult in control. Measures for membrane fouling control of AnMBR are almost the same as those of MBR, including cross flow, air sparging and membrane relaxation. For meeting discharging standard of food processing wastewater with high strength, AnMBR is a promising technology with very short process, by enhancing COD removal efficiency, controlling membrane fouling and improving energy recovery.

Cultivation of aerobic granules in a novel configuration of sequencing batch airlift reactor.

PubMed

Rezaei, Laya Siroos; Ayati, Bita; Ganjidoust, Hossein

2012-01-01

Aerobic granules can be formed in sequencing batch airlift reactors (SBAR) and sequencing batch reactors (SBR). Comparing these two systems, the SBAR has excellent mixing condition, but due to a high height-to-diameter ratio (H/D), there is no performance capability at full scale at the present time. This research examined a novel configuration of SBAR at laboratory scale (with a box structure) for industrial wastewater treatment. To evaluate chemical oxygen demand (COD) removal efficiency and granule formation of the novel reactor (R1), in comparison a conventional SBAR (R2) was operated under similar conditions during the experimental period. R1 and R2 with working volumes of 3.6 L and 4.5 L, respectively, were used to cultivate aerobic granules. Both reactors were operated for 4 h per cycle. Experiments were done at different organic loading rates (OLRs) ranging from 0.6-4.5 kg COD/m3.d for R1 and from 0.72-5.4 kg COD/m3.d for R2. After 150 days of operation, large-sized black filamentous granules with diameters of 0.5-2 mm and 2-11 mm were formed in R1 and R2, respectively. In the second part of the experiment, the efficiency of removal of a toxic substance by aerobic granules was investigated using aniline as a carbon source with a concentration in the range 1.2-6.6 kg COD/m3.d and 1.44-7.92 kg COD/m3.d in R1 and R2, respectively. It was found that COD removal efficiency of the novel airlift reactor was over 97% and 94.5% using glucose and aniline as carbon sources, respectively. Sludge volume index (SVI) was also decreased to 30 mL/g by granulation in the novel airlift reactor.

Preparation, Characterization of Coal Ash Adsorbent and Orthogonal Experimental Rsearch on Treating Printing and Dyeing Wastewater

NASA Astrophysics Data System (ADS)

Wang, Qingyu; He, Lingfeng; Shi, Liang; Chen, Xiaogang; Chen, Xin; Xu, Zizhen; Zhang, Yongli

2018-03-01

Using high temperature activated sodium flying ash and carboxymethyl chitosan as raw material to prepare carboxymethylchitosan wrapping fly-ash adsorbent (CWF), combined with iron-carbon micro-electrolysis treatment of simulated and actual printing and dyeing wastewater. The conditions for obtaining are from the literature: the best condition for CWF to treat simulated printing and dyeing wastewater pretreated with iron-carbon micro-electrolysis is that the mixing time is 10min, the resting time is 30 min, pH=6, and the adsorbent dosage is 0.75 g/L. The results showed that COD removal efficiency and decoloration rate were above 97 %, and turbidity removal rate was over 90 %. The optimum dyeing conditions were used to treat the dyeing wastewater. The decolorization rate was 97.30 %, the removal efficiency of COD was 92.44 %, and the turbidity removal rate was 90.37 %.

Solids and nutrient removal from flushed swine manure using polyacrylamides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanotti, M.B.; Hunt, P.G.

1999-12-01

Most of the organic nutrients and reduced carbon (C) materials in liquid swine manure are contained in fine suspended particles that are not separated by available mechanical separators. Treatment with polyacrylamide (PAM) polymers prior to mechanical removal or gravity settling has the potential for enhancing solids-liquid separation, thus concentrating nitrogen (N), phosphorus (P), and organic C. In this work, the authors determined PAM charge and density characteristics most desirable for swine wastewater applications and established the optimum chemical requirement. Treatments were applied to flushed manure from two swine operations in North Carolina. Cationic PAMs significantly increased solids separation while performancemore » of neutral and anionic types was not different from a control. Cationic PAMs with moderate-charge density (20%) were more effective than polymers with higher charge density. Flocs were large and effectively retained with a 1-mm screen. Optimum PAM rate varied with the amount of total suspended solids (TSS) in the liquid manure; 26 and 79 mg PAM/L for samples containing 1.5 and 4.1 g TSS/L, respectively. Corresponding TSS removal efficiencies were 90 to 94%. In contrast, screening without PAM treatment captured only 5 to 14% of the suspended solids. Polymer usage rate was consistent and averaged 2.0{degree} based on weight of dry solids produced. Volatile suspended solids (VSS) were highly correlated with TSS and comprised 79.5% of TSS. Chemical oxygen demand (COD) and organic nutrient concentrations in the effluent were also significantly decreased by PAM treatment. The decrease of COD concentration, an important consideration for odor control, was linearly related with removal of suspended solids, at a rate of 2.0 g COD/g TSS and 2.6 g COD/g VSS. Removal efficiency of organic N and P followed approximately a 1:1 relationship with removal efficiency of TSS. Chemical cost to capture 90% of the suspended solids was estimated to be $0.026 per hog per day ($2.79 per finished hog). Results obtained indicate that PAM treatment is very effective for removal of manure solids, COD, and organic nutrients from flushed swine effluents. The technology provides an attractive alternative to existing liquid manure handling methods for conserving nutrients and avoiding excessive nutrient application in areas where swine production is concentrated.« less

Anaerobic degradation of aircraft deicing fluid (ADF) in upflow anaerobic sludge blanket (UASB) reactors and the fate of ADF additives

NASA Astrophysics Data System (ADS)

Pham, Thi Tham

2002-11-01

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions were conducted in continuous mode. The development of four empirical models describing process responses (i.e., chemical oxygen demand (COD) removal efficiency, biomass specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time (HRT), and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass specific acetoclastic activity was improved by almost two-fold during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. Predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate (OLR) was increased. ADF toxicity effects were evident for 1.6% ADF at medium specific organic loadings (SOLR above 0.5 g COD/g VSS/d). In contrast, good reactor stability and excellent removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73 g COD/g VSS/d). Acclimation to ADF resulted in an initial reduction in the biomass settling velocity. The fate of ADF additives was also investigated. There was minimal sorption of benzotriazole (BT), 5-methyl-1 H-benzotriazole (MeBT), and 5,6-dimethyl-1 H-benzotriazole (DiMeBT) to anaerobic granules. A higher sorption capacity was measured for NP. Active transport may be one of the mechanisms for NP sorption. Ethylene glycol degradation experiments indicated that BT, MeBT, DiMeBT, and the nonionic surfactant Tergitol NP-4 had no significant effects on acidogenesis and methanogenesis at the concentration levels studied. A significant inhibition of acetoclastic activity was observed for NP at 100 mg/L, with acetic acid consumption rate at 38% of that for controls. No evidence for anaerobic degradation of benzotriazole and its derivatives was observed; however, both batch and continuous experiments suggested that anaerobic degradation of NP occurred. Kinetic analysis of operational data obtained for the anaerobic treatment of ADF in UASB reactors indicated that the substrate utilization rate was independent of the reactor biomass concentration. The maximum rate of substrate utilization and the half-velocity constants for ADF treatment were 28.4 g COD/L/d and 648 mg COD/L, respectively. For 1.2% ADF, the biomass yield and endogenous decay coefficients were 0.027 g VSS/g COD and 0.012 d-1 , respectively.

Assessing the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units.

PubMed

Lou, Jie-Chung; Lin, Yung-Chang

2008-02-01

Wastewater reuse can significantly reduce environmental pollution and save the water sources. The study selected Cheng-Ching Lake water treatment plant in southern Taiwan to discuss the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units. The treatment units of this plant include wastewater basin, sedimentation basin, sludge thickener and sludge dewatering facility. In this study, the treatment efficiency of SS and turbidity were 48.35-99.68% and 24.15-99.36%, respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH(3)-N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH(3)-N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible.

Use of constructed wetland systems with Arundo and Sarcocornia for polishing high salinity tannery wastewater.

PubMed

Calheiros, Cristina S C; Quitério, Paula V B; Silva, Gabriela; Crispim, Luís F C; Brix, Hans; Moura, Sandra C; Castro, Paula M L

2012-03-01

Treatment of tannery wastewater is problematic due to high and variable concentrations of complex pollutants often combined with high salinity levels. Two series of horizontal subsurface flow constructed wetlands (CWs) planted with Arundo donax and Sarcocornia fruticosa were set up after a conventional biological treatment system operating at a tannery site. The aim of the CWs was polishing organics and nitrogen from the high salinity effluent (2.2-6.6 g Cl(-) L(-1)). Both plant species established and grew well in the CW. Arundo, however, had more vigorous growth and a higher capacity to take up nutrients. The CWs were efficient in removing COD and BOD(5) with removal efficiencies varying between 51 and 80% for COD (inlet: 68-425 mg L(-1)) and between 53 and 90% for BOD(5) (inlet: 16-220 mg L(-1)). Mass removal rates were up to 615 kg COD ha(-1) d(-1) and 363 BOD(5) kg ha(-1) d(-1). Removal efficiencies were 40-93% for total P, 31-89% for NH(4)(+) and 41-90% for Total Kjeldahl Nitrogen. CW systems planted with salt tolerant plant species are a promising solution for polishing saline secondary effluent from the tannery industry to levels fulfilling the discharge standards. Copyright © 2011 Elsevier Ltd. All rights reserved.

Biofilm development during the start-up of a sulfate-reducing down-flow fluidized bed reactor at different COD/SO4(2-) ratios and HRT.

PubMed

Piña-Salazar, E Z; Cervantes, F J; Meraz, M; Celis, L B

2011-01-01

In sulfate-reducing reactors, it has been reported that the sulfate removal efficiency increases when the COD/SO4(2-) ratio is increased. The start-up of a down-flow fluidized bed reactor constitutes an important step to establish a microbial community in the biofilm able to survive under the operational bioreactor conditions in order to achieve effective removal of both sulfate and organic matter. In this work the influence of COD/SO4(2-) ratio and HRT in the development of a biofilm during reactor start-up (35 days) was studied. The reactor was inoculated with 1.6 g VSS/L of granular sludge, ground low density polyethylene was used as support material; the feed consisted of mineral medium at pH 5.5 containing 1 g COD/L (acetate:lactate, 70:30) and sodium sulfate. Four experiments were conducted at HRT of 1 or 2 days and COD/SO4(2-) ratio of 0.67 or 2.5. The results obtained indicated that a COD/SO4(2-) ratio of 2.5 and HRT 2 days allowed high sulfate and COD removal (66.1 and 69.8%, respectively), whereas maximum amount of attached biomass (1.9 g SVI/L support) and highest sulfate reducing biofilm activity (10.1 g COD-H2S/g VSS-d) was achieved at HRT of 1 day and at COD/sulfate ratios of 0.67 and 2.5, respectively, which suggests that suspended biomass also played a key role in the performance of the reactors.

Efficiency analysis of the electrocoagulation and electroflotation treatment of poultry slaughterhouse wastewater using aluminum and graphite anodes.

PubMed

Paulista, Larissa Oliveira; Presumido, Pedro Henrique; Theodoro, Joseane Debora Peruço; Pinheiro, Alexei Lorenzetti Novaes

2018-05-08

The application of electrocoagulation (EC) and electroflotation (EF) was investigated for the treatment of poultry slaughterhouse wastewater in a bench scale unit cell electrolyzer with different EC-to-EF ratios at current densities of 3, 9, and 15 mA cm -2 . The EC-to-EF ratio was controlled by current reversal using aluminum and graphite electrodes. The electrochemical treatment showed satisfactory removal efficiencies for Al coagulant loads greater than 51.8 mg L -1 . The 4/5 EC to EF ratio (69.1 mg L -1 Al and 32.2 NmL L -1 additional EF gas) and 3/5 (51.8 mg L -1 Al/64 NmL L -1 additional EF gas) presented the best results for the removal of COD (76-85%), color (93-99%), and turbidity (95-99%), with the additional benefit of reducing the electrode consumption and sludge disposal costs proportionally to the EC-to-EF ratio. The effects of the EC-to-EF ratio and the current density on efficiency of the electrochemical treatment for the removal of COD, apparent color, turbidity, TSS, TSD, and NH 3 -N were discussed in the light of the physicochemical and electrochemical processes underlying the removal mechanism for each parameter. In particular, the blow-off mechanism seems to play an important role in the NH 3 -N removal, whereas indirect electrooxidation mechanism accounts for a fraction of the soluble COD removal for the electrodes configuration used in the treatment.

Compounds of parasitic roundworm absorbing in the visible region: target molecules for detection of roundworm in Atlantic cod.

PubMed

Stormo, Svein K; Ernstsen, Arild; Nilsen, Heidi; Heia, Karsten; Sivertsen, Agnar H; Elvevoll, Edel

2004-07-01

The objective of this study was to contribute to the development of technology that will be able to replace manual operations in processing of fish fillets. Removal of parasites, black lining, remnants of skin, and bloodstains are costly and time-consuming operations to the fish processing industry. The presence of parasites in fish products tends to spoil consumers' appetites. Recent reports questioning the safety of eating cod infected with parasites might lower consumer acceptance of seafood. Presently, parasites are detected and removed manually. An average efficiency of about 75% under commercial conditions has been reported. In this study, we focused on biochemical differences between cod muscle and the prevalent anisakine nematode species (Anisakis simplex and Pseudoterranova decipiens) infecting Atlantic cod (Gadus morhua). Using reversed phase high-performance liquid chromatography equipped with a photodiode array detector, substances absorbing in the range 300 to 600 nm were identified in extracts from parasite material. These substances were not detected in extracts from cod tissue. Significant biochemical differences between cod muscle and parasite material have thus been demonstrated.

Influence of ozonation on COD in stabilized landfill leachate: Case study at Alor Pongsu landfill site, Perak

NASA Astrophysics Data System (ADS)

Zakaria, Siti Nor Farhana; Aziz, Hamidi Abdul

2017-10-01

One of an anaerobic stabilized landfill leachate in Malaysia underwent ozonation process. The sample rich in chemical oxygen demand (COD) was collected from Alor Pongsu Landfill Site, Perak (APLS). This site has been operating since year 2000. The leachate also contains other pollutants that exceeded the standard discharge limit for wastewater effluents. The effectiveness of ozone (O3) dosage, pH variation, and reaction time during ozonation was evaluated to measure the performance of O3 and determine the maximum operational conditions for this treatment. The maximum removal efficiency for COD was 50% at an ozone dosage of 31 g/m3, natural of pH 8.5, and reaction time of 60 min. The biodegradability ratio (BOD5/COD) improved from 0.08 to 0.23 after treatment with O3. The ozonation method has enhanced the biodegradability ratio and resulted high percentage removal of COD. This improvement showed that oxidation has a great potential to remediate recalcitrant pollutant wastes, such as landfill leachate.

Biotic conversion of sulphate to sulphide and abiotic conversion of sulphide to sulphur in a microbial fuel cell using cobalt oxide octahedrons as cathode catalyst.

PubMed

Chatterjee, Pritha; Ghangrekar, M M; Rao, Surampalli; Kumar, Senthil

2017-05-01

Varying chemical oxygen demand (COD) and sulphate concentrations in substrate were used to determine reaction kinetics and mass balance of organic matter and sulphate transformation in a microbial fuel cell (MFC). MFC with anodic chamber volume of 1 L, fed with wastewater having COD of 500 mg/L and sulphate of 200 mg/L, could harvest power of 54.4 mW/m 2 , at a Coulombic efficiency of 14%, with respective COD and sulphate removals of 90 and 95%. Sulphide concentration, even up to 1500 mg/L, did not inhibit anodic biochemical reactions, due to instantaneous abiotic oxidation to sulphur, at high inlet sulphate. Experiments on abiotic oxidation of sulphide to sulphur revealed maximum oxidation taking place at an anodic potential of -200 mV. More than 99% sulphate removal could be achieved in a MFC with inlet COD/sulphate of 0.75, giving around 1.33 kg/m 3  day COD removal. Bioelectrochemical conversion of sulphate facilitating sulphur recovery in a MFC makes it an interesting pollution abatement technique.

Azo dye degradation pathway and bacterial community structure in biofilm electrode reactors.

PubMed

Cao, Xian; Wang, Hui; Zhang, Shuai; Nishimura, Osamu; Li, Xianning

2018-05-31

In this study, the degradation pathway of the azo dye X-3B was explored in biofilm electrode reactors (BERs). The X-3B and chemical oxygen demand (COD) removal efficiencies were evaluated under different voltages, salinities, and temperatures. The removal efficiencies increased with increasing voltage. Additionally, the BER achieved maximum X-3B removal efficiencies of 66.26% and 75.27% at a NaCl concentration of 0.33 g L -1 and temperature of 32 °C, respectively; it achieved a COD removal efficiency of 75.64% at a NaCl concentration of 0.330 g L -1 . Fourier transform infrared spectrometry and gas chromatography-mass spectrometry analysis indicated that the X-3B biodegradation process first involved the interruption of the conjugated double-bond, resulting in aniline, benzodiazepine substance, triazine, and naphthalene ring formation. These compounds were further degraded into lower-molecular-weight products. From this, the degradation pathway of the azo dye X-3B was proposed in BERs. The relative abundances of the microbial community at the phylum and genus levels were affected by temperature, the presence of electrons, and an anaerobic environment in the BERs. To achieve better removal efficiencies, further studies on the functions of the microorganisms are needed. Copyright © 2018. Published by Elsevier Ltd.

Baffled duckweed pond system for treatment of agricultural drainage water containing pharmaceuticals.

PubMed

Bassuney, Doaa; Tawfik, Ahmed

2017-08-03

The aim of the study is to assess the efficiency of a novel bioremediation system namely baffled duckweed pond (BDWP) system for the treatment of agricultural drainage water containing pharmaceuticals at different hydraulic retention times (HRTs). The removal efficiencies of acetaminophen (ACT), amoxicillin (AMX), and ampicillin (AMP) increased from 69.3 ± 8.6 to 87.3 ± 3.5%, from 52.9 ± 9.4 to 82.9 ± 5.2%, and from 55.3 ± 7.9 to 90.6 ± 2.8% at increasing the HRT from 6 to 8 days, respectively. However, ACT, AMX, and AMP removal efficiencies were slightly improved at increasing the HRT from 8 to 12 days. Diclofenac (DFC) removal efficiencies amounted to 56.6 ± 11.6, 55.7 ± 11.9, and 28.3 ± 12.9% at an HRTs of 12, 8, and 6 days, respectively. The results showed no relationship between the uptake/absorption of pharmaceuticals fractions and BOD 5 /chemical oxygen demand (COD) ratio except ACT where R 2 was 0.84. The effect of COD/N ratio on the removal efficiency of pharmaceuticals fractions was slight. Additional removal of pharmaceuticals fractions and nitrification occurred in carrier sponge media situated in the last compartment of the BDWP.

Study on the effect of landfill leachate on nutrient removal from municipal wastewater.

PubMed

Yuan, Qiuyan; Jia, Huijun; Poveda, Mario

2016-05-01

In this study, landfill leachate with and without pre-treatment was co-treated with municipal wastewater at different mixing ratios. The leachate pre-treatment was achieved by air stripping to removal ammonia. The objective of this study was to investigate the effect of landfill leachate on nutrient removal of the wastewater treatment process. It was demonstrated that when landfill leachate was co-treated with municipal wastewater, the high ammonia concentration in the leachate did not have a negative impact on the nitrification. The system was able to adapt to the environment and was able to improve nitrification capacity. The readily biodegradable portion of chemical oxygen demand (COD) in the leachate was utilized by the system to improve phosphorus and nitrate removal. However, this portion was small and majority of the COD ended up in the effluent thereby decreased the quality of the effluent. The study showed that the 2.5% mixing ratio of leachate with wastewater improved the overall biological nutrient removal process of the system without compromising the COD removal efficiency. Copyright © 2015. Published by Elsevier B.V.

Buoyant Filter Bio-Reactor (BFBR)--a novel anaerobic wastewater treatment unit.

PubMed

Panicker, Soosan J; Philipose, M C; Haridas, Ajit

2008-01-01

The Buoyant Filter Bio-Reactor (BFBR) is a novel and very efficient method for the treatment of complex wastewater. Sewage is a complex wastewater containing insoluble COD contributed by fat and proteins. The fat and proteins present in the domestic sewage cause operational problems and underperformance in the Upflow Anaerobic Sludge Blanket Reactor, used now for treating sewage anaerobically. The biogas yield from the BFBR is 0.36 m3/kg COD reduced and the methane content was about 70-80%. Production of methane by anaerobic digestion of organic waste had the benefit of lower energy costs for treatment and is thus environmentally beneficial to the society by providing a clean fuel from renewable feed stocks. The BFBR achieved a COD removal efficiency of 80-90% for an organic loading rate of 4.5 kg/m3/d at a hydraulic retention time of 3.25 hours. The effluent COD was less than 100 mg/l, thus saving on secondary treatment cost. No pretreatment like sedimentation was required for the influent to the BFBR. The BFBR can produce low turbidity effluent as in the activated sludge process (ASP). The land area required for the BFBR treatment plant is less when compared to ASP plant. Hence the problem of scarcity of land for the treatment plant is reduced. The total expenditure for erecting the unit was less than 50% as that of conventional ASP for the same COD removal efficiency including land cost. IWA Publishing 2008.

Simultaneous nitrification and denitrification in a novel membrane bioelectrochemical reactor with low membrane fouling tendency.

PubMed

Li, Hui; Zuo, Wei; Tian, Yu; Zhang, Jun; Di, Shijing; Li, Lipin; Su, Xinying

2017-02-01

Microbial fuel cells (MFCs) can use nitrate as a cathodic electron acceptor for electrochemical denitrification, yet there is little knowledge about how to apply them into current wastewater treatment process to achieve efficient nitrogen removal. In this study, two dual-chamber MFCs were integrated with an aerobic membrane bioreactor to construct a novel membrane bioelectrochemical reactor (MBER) for simultaneous nitrification and denitrification under specific aeration. The effects of chemical oxygen demand (COD) loading rate, COD/N ratio, hydraulic retention time (HRT), and external resistance on the system performance were investigated. High effluent quality was obtained in the MBER in terms of COD and ammonium. During the operation, denitrification simultaneously occurred with nitrification at the bio-cathode of the MBER, achieving a maximal nitrogen removal efficiency of 84.3 %. A maximum power density of 1.8 W/m 3 and a current density of 8.5 A/m 3 were achieved with a coulombic efficiency of 12.1 %. Furthermore, compared to the control system, the MBER exhibited lower membrane fouling tendency due to mixed liquor volatile suspended solids (MLVSSs) and extracellular polymeric substance (EPS) reductions, EPSp/EPSc ratio decrease, and particle size increase of the sludge. These results suggest that the MBER holds potential for efficient nitrogen removal, electricity production, and membrane fouling mitigation.

A modeling understanding on the phosphorous removal performances of A2O and reversed A2O processes in a full-scale wastewater treatment plant.

PubMed

Xie, Wen-Ming; Zeng, Raymond J; Li, Wen-Wei; Wang, Guo-Xiang; Zhang, Li-Min

2018-05-31

Reversed A 2 O process (anoxic-anaerobic-aerobic) and conventional A 2 O process (anaerobic-anoxic-aerobic) are widely used in many wastewater treatment plants (WWTPs) in Asia. However, at present, there are still no consistent results to figure out which process has better total phosphorous (TP) removal performance and the mechanism for this difference was not clear yet. In this study, the treatment performances of both processes were compared in the same full-scale WWTP and the TP removal dynamics was analyzed by a modeling method. The treatment performance of full-scale WWTP showed the TP removal efficiency of the reversed A 2 O process was more efficient than in the conventional A 2 O process. The modeling results further reveal that the TP removal depends highly on the concentration and composition of influent COD. It had more efficient TP removal than the conventional A 2 O process only under conditions of sufficient influent COD and high fermentation products content. This study may lay a foundation for appropriate selection and optimization of treatment processes to suit practical wastewater properties.

Mesophilic and thermophilic activated sludge post-treatment of paper mill process water.

PubMed

Vogelaar, J C T; Bouwhuis, E; Klapwijk, A; Spanjers, H; van Lier, J B

2002-04-01

Increasing system closure in paper mills and higher process water temperatures make the applicability of thermophilic treatment systems increasingly important. The use of activated sludge as a suitable thermophilic post-treatment system for anaerobically pre-treated paper process water from a paper mill using recycled wastepaper was studied. Two lab-scale plug flow activated sludge reactors were run in parallel for 6 months; a thermophilic reactor at 55 degrees C and a reference reactor at 30 degrees C. Both reactors were operated simultaneously at 20, 15 and 10 days SRT. The effects of temperature and SRT on sludge settleability and chemical oxygen demand (COD) removal efficiencies of different fractions were studied. Total COD removal percentages over the whole experimental period were 58+/-5% at 30 degrees C and 48 +/- 10% at 55 degrees C. The effect of the SRT on the total COD removal was negligible. Differences in total COD removal between both systems were due to a lesser removal of soluble and colloidal COD at 55 degrees C compared to the reference system. At 30 degrees C, colloidal COD removal percentages were 65+/-25%, 75+/-17% and 86+/-22% at 20, 15 and 10 days SRT, respectively. At 55 degrees C, these percentages were 48+/-34%, 40+/-28% and 70+/-25%, respectively. The effluent concentrations of colloidal COD in both systems were related to the influent concentration of colloidal material. The thermophilic sludge was not able to retain influent colloidal material as well as the mesophilic sludge causing a higher thermophilic effluent turbidity. Sludge settling properties were excellent in both reactor systems. These were neither temperature nor SRT dependent but were rather caused by extensive calcium precipitation in the aeration tanks creating a very dense sludge. For application in the board industry, a thermophilic in line treatment system seems feasible. The higher effluent turbidity is most likely offset by the energy gains of treatment under thermophilic conditions.

Integrating sequencing batch reactor with bio-electrochemical treatment for augmenting remediation efficiency of complex petrochemical wastewater.

PubMed

Yeruva, Dileep Kumar; Jukuri, Srinivas; Velvizhi, G; Naresh Kumar, A; Swamy, Y V; Venkata Mohan, S

2015-01-01

The present study evaluates the sequential integration of two advanced biological treatment methods viz., sequencing batch reactor (SBR) and bioelectrochemical treatment systems (BET) for the treatment of real-field petrochemical wastewater (PCW). Initially two SBR reactors were operated in aerobic (SBR(Ae)) and anoxic (SBR(Ax)) microenvironments with an organic loading rate (OLR) of 9.68 kg COD/m(3)-day. Relatively, SBR(Ax) showed higher substrate degradation (3.34 kg COD/m(3)-day) compared to SBR(Ae) (2.9 kg COD/m(3)-day). To further improve treatment efficiency, the effluents from SBR process were fed to BET reactors. BET(Ax) depicted higher SDR (1.92 kg COD/m(3)-day) with simultaneous power generation (17.12 mW/m(2)) followed by BET(Ae) (1.80 kg COD/m(3)-day; 14.25 mW/m(2)). Integrating both the processes documented significant improvement in COD removal efficiency due to the flexibility of combining multiple microenvironments sequentially. Results were supported with GC-MS and FTIR, which confirmed the increment in biodegradability of wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

Treatment of Actual Chemical Wastewater by a Heterogeneous Fenton Process Using Natural Pyrite

PubMed Central

Sun, Liang; Li, Yan; Li, Aimin

2015-01-01

Wastewater from chemical plants has remarkable antibiotic effects on the microorganisms in traditional biological treatment processes. An enhanced Fenton system catalyzed by natural pyrite was developed to degrade this kind of wastewater. Approximately 30% chemical oxygen demand (COD) was removed within 120 min when 50 mmol/L H2O2 and 10 g/L natural pyrite were used at initial pH from 1.8 to 7. A BOD5/COD enhancement efficiency of 210% and an acute biotoxicity removal efficiency of 84% were achieved. The COD removal efficiency was less sensitive to initial pH than was the classic Fenton process. Excessive amounts of pyrite and H2O2 did not negatively affect the pyrite Fenton system. The amount of aniline generated indicated that nitrobenzene reduction by pyrite was promoted using a low initial concentration of H2O2 (<5 mmol/L). Fluorescence excitation emission matrix analyses illustrated that H2O2 facilitated the reduction by natural pyrite of organic molecules containing an electron-withdrawing group to electron-donating group. Thus, the Fenton-like process catalyzed by pyrite can remediate wastewater containing organic pollutants under mild reaction conditions and provide an alternative environmentally friendly method by which to reuse natural pyrite. PMID:26516893

Electrocoagulation of bio-filtrated landfill leachate: Fractionation of organic matter and influence of anode materials.

PubMed

Dia, Oumar; Drogui, Patrick; Buelna, Gerardo; Dubé, Rino; Ihsen, Ben Salah

2017-02-01

Electrocoagulation (EC) was employed to treat residual organic matter from a landfill leachate pretreated by an aerated bio-filter system. Organic matter (humic acids (HA), fulvic acids (FA) and hydrophilic compounds (Hyl)) was fractionated using DAX-8 resin in order to estimate the efficiency of EC on each fraction. Initial characterization of the bio-filtrated landfill leachate showed that humic substances (HA + FA) represented nearly 90% of TOC. The effects of current densities, type of anode (Aluminum versus iron), and treatment time on the performance of COD removal were investigated. The best COD removal performances were recorded at a current density ranging between 8.0 and 10 mA cm -2 during 20 min of treatment time. Under these conditions, 70% and 65% of COD were removed using aluminum and iron electrodes, respectively. The fractionating of organic matter after EC treatment revealed that HA was completely removed using either aluminum or iron anode. However, FA and Hyl fractions were partially removed, with the percentages varying from 57 to 60% and 37-46%, respectively. FA and Hyl removal were quite similar using either aluminum or iron anode. Likewise, a significant decrease in 254-nm absorbance was recorded (UV 254 removal of 79-80%) using either type of anode. These results proved that EC is a suitable and efficient approach for treating the residual refractory organic matter from a landfill leachate previously treated by a biological system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic digestion of blackwater from vacuum toilets and kitchen refuse in a continuous stirred tank reactor (CSTR).

PubMed

Wendland, C; Deegener, S; Behrendt, J; Toshev, P; Otterpohl, R

2007-01-01

The objective of this research was mesophilic anaerobic digestion of blackwater from vacuum toilets (BW) and kitchen refuse (KR) in a CSTR within an ecological sanitation system. A detailed investigation of the BW characteristics was carried out. Research on anaerobic digestion was performed with CSTR of 101 volume at HRT of 10, 15 and 20 days. The digestion of BW at 20 days HRT showed stable performance without inhibition effects, in spite of relatively high ammonium concentrations. The removal of total and particulate COD was 61% and 53%, respectively, and the methane yield 10/CH4/cap/day. The addition of kitchen refuse (KR) improved the performance of the CSTR in terms of COD removal efficiency and methane yield. At 20 days HRT the removal of total and particulate COD increased up to 71% and 67%, respectively, and the methane yield to 27/CH4/cap/day. The results at 15 days HRT showed similar performance. At HRT of 10 days, the anaerobic treatment was limited but reached steady state conditions at higher VFA concentrations in the effluent, with a decrease of COD removal of 30 to 33% and of methane yields of 19 to 21%.

Comparison of the performance of MBBR and SBR systems for the treatment of anaerobic reactor biowaste effluent.

PubMed

Comett-Ambriz, I; Gonzalez-Martinez, S; Wilderer, P

2003-01-01

Anaerobic reactor biowaste effluent was treated with biofilm and activated sludge sequencing batch reactors to compare the performance of both systems. The treatment targets were organic carbon removal and nitrification. The pilot plant was operated in two phases. During the first phase, it was operated like a Moving Bed Biofilm Reactor (MBBR) with the Natrix media, with a specific surface area of 210 m2/m3. The MBBR was operated under Sequencing Batch Reactor (SBR) modality with three 8-hour cycles per day over 70 days. During the second phase of the experiment, the pilot plant was operated over 79 days as a SBR. In both phases the influent was fed to the reactor at a flow rate corresponding to a Hydraulic Retention Time (HRT) of 4 days. Both systems presented a good carbon removal for this specific wastewater. The Chemical Oxygen Demand (COD) total removal was 53% for MBBR and 55% for SBR. MBBR offered a higher dissolved COD removal (40%) than SBR (30%). The limited COD removal achieved is in agreement with the high COD to BOD5 ratio (1/3) of the influent wastewater. In both systems a complete nitrification was obtained. The different efficiencies in both systems are related to the different biomass concentrations.

Catalytic mechanism of cationic red GTL at wide pH using the Mo-Zn-Al-O nanocatalyst under room conditions.

PubMed

Xu, Yin; Li, Xiaoyi; Sun, Dezhi

2014-09-01

Catalytic mechanism of cationic red GTL at wide pH using the Mo-Zn-Al-O nanocatalyst under room conditions was investigated. The experimental results indicate that initial pH significantly affected the removal of cationic red GTL, the removal of COD, the pH value and residual oxygen in the reaction. In the range of pH value from 4 to 10, decolorization of cationic red GTL was almost above 90%. COD removal efficiency was enhanced with the decrease of pH in CWAO process and 79% of the COD was removed at pH 4.0, whereas only 57% COD removal was observed at pH 10.0. The terminal pH was in the range of 5.0-6.0 and the highest terminal concentrations of aqueous oxygen with 5.5 mg/L were observed at pH = 4.0. The radical inhibition experiments also carried out and the generation of *OH and 1O2 in catalytic wet air oxidation process were detected. It was found that the degradation of cationic red GTL occurs mainly via oxidation by 1O2 radical generated by Mo-Zn-Al-O nanocatalyst under acid conditions and *OH radical under alkaline conditions.

Treatment of old landfill leachate with high ammonium content using aerobic granular sludge.

PubMed

Ren, Yanan; Ferraz, Fernanda; Kang, Abbass Jafari; Yuan, Qiuyan

2017-01-01

Aerobic granular sludge has become an attractive alternative to the conventional activated sludge due to its high settling velocity, compact structure, and higher tolerance to toxic substances and adverse conditions. Aerobic granular sludge process has been studied intensively in the treatment of municipal and industrial wastewater. However, information on leachate treatment using aerobic granular sludge is very limited. This study investigated the treatment performance of old landfill leachate with different levels of ammonium using two aerobic sequencing batch reactors (SBR): an activated sludge SBR (ASBR) and a granular sludge SBR (GSBR). Aerobic granules were successfully developed using old leachate with low ammonium concentration (136 mg L -1  NH 4 + -N). The GSBR obtained a stable chemical oxygen demand (COD) removal of 70% after 15 days of operation; while the ASBR required a start-up of at least 30 days and obtained unstable COD removal varying from 38 to 70%. Ammonium concentration was gradually increased in both reactors. Increasing influent ammonium concentration to 225 mg L -1  N, the GSBR removed 73 ± 8% of COD; while COD removal of the ASBR was 59 ± 9%. The GSBR was also more efficient than the ASBR for nitrogen removal. The granular sludge could adapt to the increasing concentrations of ammonium, achieving 95 ± 7% removal efficiency at a maximum influent concentration of 465 mg L -1  N. Ammonium removal of 96 ± 5% was obtained by the ASBR when it was fed with a maximum of 217 mg L -1  NH 4 + -N. However, the ASBR was partially inhibited by free-ammonia and nitrite accumulation rate increased up to 85%. Free-nitrous acid and the low biodegradability of organic carbon were likely the main factors affecting phosphorus removal. The results from this research suggested that aerobic granular sludge have advantage over activated sludge in leachate treatment.

Optimizing the performance of microbial fuel cells fed a combination of different synthetic organic fractions in municipal solid waste.

PubMed

Pendyala, Brahmaiah; Chaganti, Subba Rao; Lalman, Jerald A; Heath, Daniel D

2016-03-01

The objective of this study was to establish the impact of different steam exploded organic fractions in municipal solid waste (MSW) on electricity production using microbial fuel cells (MFCs). In particular, the influence of individual steam exploded liquefied waste components (food waste (FW), paper-cardboard waste (PCW) and garden waste (GW)) and their blends on chemical oxygen demand (COD) removal, columbic efficiency (CE) and microbial diversity was examined using a mixture design. Maximum power densities from 0.56 to 0.83 W m(-2) were observed for MFCs fed with different feedstocks. The maximum COD removed and minimum CE were observed for a GW feed. However, a reverse trend (minimum COD removed and maximum CE) was observed for the FW feed. A maximum COD removal (78%) accompanied with a maximum CE (24%) was observed for a combined feed of FW, PCW plus GW in a 1:1:1 ratio. Lactate, the major byproduct detected, was unutilized by the anodic biofilm community. The organic fraction of municipal solid waste (OFMSW) could serve as a potential feedstock for electricity generation in MFCs; however, elevated protein levels will lead to reduced COD removal. The microbial communities in cultures fed FW and PCW was highly diversified; however, the communities in cultures fed FW or a feed mixture containing high FW levels were similar and dominated by Bacteroidetes and β-proteobacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of organic carbon and nitrogen in a membraneless flow-through microbial electrolysis cell.

PubMed

Hussain, Abid; Lebrun, Frédérique Matteau; Tartakovsky, Boris

2017-07-01

This study evaluated performance of an upflow membraneless microbial electrolysis cell (MEC) with flow-through electrodes for wastewater treatment. First, methane production and COD removal were evaluated in continuous flow experiments carried out using synthetic and municipal wastewater. A 29-75% increase in methane production was observed under bioelectrochemical conditions as compared to an anaerobic control. Next, simultaneous removal of COD and nitrogen was studied under microaerobic conditions created by continuous air injection to the anodic compartment of the MEC. While the presence of oxygen decreased Coulombic efficiency due to aerobic degradation of COD, enhanced ammonium removal with near zero nitrite and nitrate effluent concentrations was observed. Evidence of direct ammonium oxidation at the anode as well as nitrite and nitrate reduction at the cathode was obtained by comparing performances of MECs operated under anaerobic and microaerobic conditions with the control reactor operated at zero applied voltage. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Biomass and pigments production in photosynthetic bacteria wastewater treatment: effects of light sources.

PubMed

Zhou, Qin; Zhang, Panyue; Zhang, Guangming

2015-03-01

This study is aimed at enhancing biomass and pigments production together with pollution removal in photosynthetic bacteria (PSB) wastewater treatment via different light sources. Red, yellow, blue, white LED and incandescent lamp were used. Results showed different light sources had great effects on the PSB. PSB had the highest biomass production, COD removal and biomass yield with red LED. The corresponding biomass, COD removal and biomass yield reached 2580 mg/L, 88.6% and 0.49 mg-biomass/mg-COD-removal, respectively. The hydraulic retention time of wastewater treatment could be shortened to 72 h with red LED. Mechanism analysis showed higher ATP was produced with red LED than others. Light sources could significantly affect the pigments production. The pigments productions were greatly higher with LED than incandescent lamp. Yellow LED had the highest pigments production while red LED produced the highest carotenoid/bacteriochlorophyll ratio. Considering both efficiency and energy cost, red LED was the optimal light source. Copyright © 2014 Elsevier Ltd. All rights reserved.

Antibiotic Fermentation Broth Treatment by a pilot upflow anaerobic sludge bed reactor and kinetic modeling.

PubMed

Coskun, T; Kabuk, H A; Varinca, K B; Debik, E; Durak, I; Kavurt, C

2012-10-01

In this study, an upflow anaerobic sludge blanket (UASB) mesophilic reactor was used to remove antibiotic fermentation broth wastewater. The hydraulic retention time was held constant at 13.3 days. The volumetric organic loading value increased from 0.33 to 7.43 kg(COD)m(-3)d(-1) using antibiotic fermentation broth wastewater gradually diluted with various ratios of domestic wastewater. A COD removal efficiency of 95.7% was obtained with a maximum yield of 3,700 L d(-1) methane gas production. The results of the study were interpreted using the modified Stover-Kincannon, first-order, substrate mass balance and Van der Meer and Heertjes kinetic models. The obtained kinetic coefficients showed that antibiotic fermentation broth wastewater can be successfully treated using a UASB reactor while taking COD removal and methane production into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simultaneous enzymatic hydrolysis and anaerobic biodegradation of lipid-rich wastewater from poultry industry

NASA Astrophysics Data System (ADS)

Dors, Gisanara; Mendes, Adriano A.; Pereira, Ernandes B.; de Castro, Heizir F.; Furigo, Agenor

2013-03-01

Simultaneous enzymatic hydrolysis and anaerobic biodegradation of lipid-rich wastewater from poultry industry with porcine pancreatic lipase at different concentrations (from 1.0 to 3.0 g L-1) were performed. The efficiency of the enzymatic pretreatment was measured by the Chemical Oxygen Demand (COD) removal and formation of methane. All samples pretreated with lipase showed a positive effect on the COD removal and formation of methane. After 30 days of anaerobic biodegradation the methane production varied from 569 ± 95 to 1,101 ± 10 mL for crude wastewater and pretreated at 3.0 g L-1 enzyme, respectively. COD removal of wastewater supplemented at different enzyme concentrations was found to be threefold higher than crude wastewater. The use of lipases seems to be a promising alternative for treating lipid-rich wastewaters such as those from the poultry industry.

AnSBBR applied to organic matter and sulfate removal: interaction effect between feed strategy and COD/sulfate ratio.

PubMed

Friedl, Gregor F; Mockaitis, Gustavo; Rodrigues, José A D; Ratusznei, Suzana M; Zaiat, Marcelo; Foresti, Eugênio

2009-10-01

A mechanically stirred anaerobic sequencing batch reactor containing anaerobic biomass immobilized on polyurethane foam cubes, treating low-strength synthetic wastewater (500 mg COD L(-1)), was operated under different operational conditions to assess the removal of organic matter and sulfate. These conditions were related to fill time, defined by the following feed strategies: batch mode of 10 min, fed-batch mode of 3 h and fed-batch mode of 6 h, and COD/[SO(4)(2-)] ratios of 1.34, 0.67, and 0.34 defined by organic matter concentration of 500 mg COD L(-1) and sulfate concentrations of 373, 746, and 1,493 mg SO(4)(2-) L(-1) in the influent. Thus, nine assays were performed to investigate the influence of each of these parameters, as well as the interaction effect, on the performance of the system. The reactor operated with agitation of 400 rpm, total volume of 4.0 L, and treated 2.0 L synthetic wastewater in 8-h cycles at 30 +/- 1 degrees C. During all assays, the reactor showed operational stability in relation to the monitored variables such as COD, sulfate, sulfide, sulfite, volatile acids, bicarbonate alkalinity, and solids, thus demonstrating the potential to apply this technology to the combined removal of organic matter and sulfate. In general, the results showed that the 3-h fed-batch operation with a COD/[SO(4)(2-)] ratio of 0.34 presented the best conditions for organic matter removal (89%). The best efficiency for sulfate removal (71%) was accomplished during the assay with a COD/[SO(4)(2-)] ratio of 1.34 and a fill time of 6 h. It was also observed that as fill time and sulfate concentration in the influent increased, the ratio between removed sulfate load and removed organic load also increased. However, it should be pointed out that the aim of this study was not to optimize the removal of organic matter and sulfate, but rather to analyze the behavior of the reactor during the different feed strategies and applied COD/[SO(4)(2-)] ratios, and mainly to analyze the interaction effect, an aspect that has not yet been explored in the literature for batch reactors.

Biotreatment of zinc-containing wastewater in a sulfidogenic CSTR: Performance and artificial neural network (ANN) modelling studies.

PubMed

Sahinkaya, Erkan

2009-05-15

Sulfidogenic treatment of sulfate (2-10g/L) and zinc (65-677mg/L) containing simulated wastewater was studied in a mesophilic (35 degrees C) CSTR. Ethanol was supplemented (COD/sulfate=0.67) as carbon and energy source for sulfate-reducing bacteria (SRB). The robustness of the system was studied by increasing Zn, COD and sulfate loadings. Sulfate removal efficiency, which was 70% at 2g/L feed sulfate concentration, steadily decreased with increasing feed sulfate concentration and reached 40% at 10g/L. Over 99% Zn removal was attained due to the formation of zinc-sulfide precipitate. COD removal efficiency at 2g/L feed sulfate concentration was over 94%, whereas, it steadily decreased due to the accumulation of acetate at higher loadings. Alkalinity produced from acetate oxidation increased wastewater pH remarkably when feed sulfate concentration was 5g/L or lower. Electron flow from carbon oxidation to sulfate reduction averaged 83+/-13%. The rest of the electrons were most likely coupled with fermentative reactions as the amount of methane production was insignificant. The developed ANN model was very successful as an excellent to reasonable match was obtained between the measured and the predicted concentrations of sulfate (R=0.998), COD (R=0.993), acetate (R=0.976) and zinc (R=0.827) in the CSTR effluent.

Comparison of phthalic acid removal from aqueous solution by electrochemical methods: Optimization, kinetic and sludge study.

PubMed

Sandhwar, Vishal Kumar; Prasad, Basheshwar

2017-12-01

In this work, comparative study between electrochemical processes such as electrocoagulation (EC), peroxi-coagulation (PC) and peroxi-electrocoagulation (PEC) was performed for the removal of phthalic acid (PA) and chemical oxygen demand (COD) from aqueous medium. Initially, acid treatment was studied at various pH (1-3) and temperature (10-55 °C). Subsequently, the supernatant was re-treated by electrochemical processes such as EC, PC and PEC separately. Independent parameters viz. pH, current density (CD), electrolyte concentration (m), electrode gap (g), H 2 O 2 concentration and electrolysis time (t) were optimized by Central Composite Design (CCD) for these electrochemical processes. All three processes were compared based on removal, energy consumption, kinetic analysis, operating cost and sludge characteristics. In this study, PEC process was found more efficient among EC, PC and PEC processes in order to get maximum removal, minimum energy consumption and minimum operating cost. Maximum removal of PA- 68.21%, 74.36%, 82.25% & COD- 64.79%, 68.15%, 75.21% with energy consumption - 120.95, 97.51, 65.68 (kWh/kg COD removed) were attained through EC, PC and PEC processes respectively at their corresponding optimum conditions. Results indicated that PA and COD removals are in order of PEC > PC > EC under optimum conditions. First order kinetic model was found able to describe the degradation kinetics and provided best correlation for the removal rate within the acceptable error range. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of the Treatment Process of Landfill Leachate Using the Toxicity Assessment Method

PubMed Central

Qiu, Aifeng; Cai, Qiang; Zhao, Yuan; Guo, Yingqing; Zhao, Liqian

2016-01-01

Landfill leachate is composed of a complex composition with strong biological toxicity. The combined treatment process of coagulation and sedimentation, anaerobics, electrolysis, and aerobics was set up to treat landfill leachate. This paper explores the effect of different operational parameters of coagulation and sedimentation tanks and electrolytic cells, while investigating the combined process for the removal efficiency of physicochemical indices after processing the landfill leachate. Meanwhile, a battery of toxicity tests with Vibrio fischeri, zebrafish larvae, and embryos were conducted to evaluate acute toxicity and calculated the toxicity reduction efficiency after each treatment process. The combined treatment process resulted in a 100% removal efficiency of Cu, Cd and Zn, and a 93.50% and an 87.44% removal efficiency of Ni and Cr, respectively. The overall removal efficiency of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), and total nitrogen (TN) were 93.57%, 97.46% and 73.60%, respectively. In addition, toxicity test results showed that the acute toxicity of landfill leachate had also been reduced significantly: toxicity units (TU) decreased from 84.75 to 12.00 for zebrafish larvae, from 82.64 to 10.55 for zebrafish embryos, and from 3.41 to 0.63 for Vibrio fischeri. The combined treatment process was proved to be an efficient treatment method to remove heavy metals, COD, NH4+-N, and acute bio-toxicity of landfill leachate. PMID:28009808

Evaluation of the Treatment Process of Landfill Leachate Using the Toxicity Assessment Method.

PubMed

Qiu, Aifeng; Cai, Qiang; Zhao, Yuan; Guo, Yingqing; Zhao, Liqian

2016-12-21

Landfill leachate is composed of a complex composition with strong biological toxicity. The combined treatment process of coagulation and sedimentation, anaerobics, electrolysis, and aerobics was set up to treat landfill leachate. This paper explores the effect of different operational parameters of coagulation and sedimentation tanks and electrolytic cells, while investigating the combined process for the removal efficiency of physicochemical indices after processing the landfill leachate. Meanwhile, a battery of toxicity tests with Vibrio fischeri , zebrafish larvae, and embryos were conducted to evaluate acute toxicity and calculated the toxicity reduction efficiency after each treatment process. The combined treatment process resulted in a 100% removal efficiency of Cu, Cd and Zn, and a 93.50% and an 87.44% removal efficiency of Ni and Cr, respectively. The overall removal efficiency of chemical oxygen demand (COD), ammonium nitrogen (NH₄⁺-N), and total nitrogen (TN) were 93.57%, 97.46% and 73.60%, respectively. In addition, toxicity test results showed that the acute toxicity of landfill leachate had also been reduced significantly: toxicity units (TU) decreased from 84.75 to 12.00 for zebrafish larvae, from 82.64 to 10.55 for zebrafish embryos, and from 3.41 to 0.63 for Vibrio fischeri . The combined treatment process was proved to be an efficient treatment method to remove heavy metals, COD, NH₄⁺-N, and acute bio-toxicity of landfill leachate.

Comparative study on the treatment of raw and biologically treated textile effluents through submerged nanofiltration.

PubMed

Chen, Qing; Yang, Ying; Zhou, Mengsi; Liu, Meihong; Yu, Sanchuan; Gao, Congjie

2015-03-02

Raw and biologically treated textile effluents were submerged filtrated using lab-fabricated hollow fiber nanofiltration membrane with a molecular weight cut-off of about 650 g/mol. Permeate flux, chemical oxygen demand (COD) reduction, color removal, membrane fouling, and cleaning were investigated and compared by varying the trans-membrane pressure (TMP) and volume concentrating factor (VCF). It was found that both raw and biologically treated textile effluents could be efficiently treated through submerged nanofiltration. The increase of TMP resulted in a decline in water permeability, COD reduction, color removal, and flux recovery ratio, while the increase of VCF resulted in both increased COD reduction and color removal. Under the TMP of 0.4 bar and VCF of 5.0, fluxes of 1.96 and 2.59 l/m(2)h, COD reductions of 95.7 and 94.2%, color removals of 99.0, and 97.3% and flux recovery ratios of 91.1 and 92.9% could be obtained in filtration of raw and biologically treated effluents, respectively. After filtration, the COD and color contents of the raw effluent declined sharply from 1780 to 325 mg/l and 1.200 to 0.060 Abs/cm, respectively, while for the biologically treated effluent, they decreased from 780 to 180 mg/l and 0.370 to 0.045 Abs/cm, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Veratric acid removal from water by electrochemical oxidation on BDD anode

NASA Astrophysics Data System (ADS)

Jum'h, Inshad; Abdelhay, Arwa; Telfah, Ahmad; Al-Akhras, M.-Ali; Al-Kazwini, Akeel; Rosiwal, Stefan

2018-02-01

The efficiency of boron doped diamond (BDD) in the electrochemical treatment of synthetically contaminated water with veratric acid (VA), one kind of polyphenolic type compounds, is investigated in this work. A BDD electrode was practically fabricated using hot filament chemical vapor deposition (HFCVD). Later on, the BDD electrode was implemented as an anode in a batch electrolytic reactor. The effect of operating factors such as the initial concentration of VA, NaCl addition, and supporting electrolyte type (H2SO4, H3PO4 and Na2SO4) was studied. The chemical oxygen demand (COD) measurements were conducted to study the VA electrolysis kinetics. The experimental data suggested that sodium sulfate was the best supporting electrolyte as the COD removal reached a percentage of 100% using 1 mmol/dm3 as VA concentration. The kinetics of the COD decay of the VA electrolysis were found to obey the pseudo-first order model. Remarkably, the electrolysis process is significantly speeded up once chloride is added to the reaction. The complete COD removal was achieved in 60 minutes of treatment.

Effects of titanium dioxide mediated dairy waste activated sludge deflocculation on the efficiency of bacterial disintegration and cost of sludge management.

PubMed

Godvin Sharmila, V; Kavitha, S; Rajashankar, K; Yeom, Ick Tae; Rajesh Banu, J

2015-12-01

This investigation explores the influence of titanium dioxide (TiO2) in deflocculating (removal of extracellular polymeric substance - EPS) the sludge and subsequent biomass disintegration by bacterial pretreatment. The EPS removed at an optimized TiO2 dosage of 0.03g/g of SS of TiO2 and a solar radiation exposure time of 15min to enhance the subsequent bacterial disintegration. The outcomes of the bacterial pretreatment reveal SS reduction and COD solubilization for the deflocculated (EPS removed and bacterially pretreated) sludge was observed to be 22.8% and 22.9% which was comparatively greater than flocculated (raw sludge inoculated with bacteria) and control (raw) sludge. The higher methane production potential of about 0.43(gCOD/gVSS) was obtained in deflocculated sludge than the flocculated (0.20gCOD/gVSS) and control (0.073gCOD/gVSS). Economic assessment of this study provides a net profit of about 131.9USD/Ton in deflocculated sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of coagulation-flocculation treatment on paper-recycling wastewater: Application of response surface methodology.

PubMed

Birjandi, Noushin; Younesi, Habibollah; Bahramifar, Nader; Ghafari, Shahin; Zinatizadeh, Ali Akbar; Sethupathi, Sumathi

2013-01-01

The application of coagulation-flocculation (CF) process for treating the paper-recycling wastewater in jar-test experiment was employed. The purpose of the study was aimed to examine the efficiency of alum and poly aluminum chloride (PACl) in combination with a cationic polyacrylamide (C-PAM) in removal of chemical oxygen demand (COD) and turbidity from paper-recycling wastewater. Optimization of CF process were performed by varying independent parameters (coagulants dosage, flocculants dosage, initial COD and pH) using a central composite design (CCD) under response surface methodology (RSM). Maximum set required 4.5 as pH, 40 mg/L coagulants dosage and 4.5 mg/L flocculants dosage at which gave 92% reduction of turbidity, 97% of COD removal and SVI 80 mL/g. The best coagulant and flocculants were alum and chemfloc 3876 at dose of 41 and 7.52 mg/L, respectively, correspondingly at pH of 6.85. These conditions gave 91.30% COD and 95.82% turbidity removals and 12 mL/g SVI.

High-strength wastewater treatment in a pure oxygen thermophilic process: 11-year operation and monitoring of different plant configurations.

PubMed

Collivignarelli, M C; Bertanza, G; Sordi, M; Pedrazzani, R

2015-01-01

This research was carried out on a full-scale pure oxygen thermophilic plant, operated and monitored throughout a period of 11 years. The plant treats 60,000 t y⁻¹ (year 2013) of high-strength industrial wastewaters deriving mainly from pharmaceuticals and detergents production and landfill leachate. Three different plant configurations were consecutively adopted: (1) biological reactor + final clarifier and sludge recirculation (2002-2005); (2) biological reactor + ultrafiltration: membrane biological reactor (MBR) (2006); and (3) MBR + nanofiltration (since 2007). Progressive plant upgrading yielded a performance improvement chemical oxygen demand (COD) removal efficiency was enhanced by 17% and 12% after the first and second plant modification, respectively. Moreover, COD abatement efficiency exhibited a greater stability, notwithstanding high variability of the influent load. In addition, the following relevant outcomes appeared from the plant monitoring (present configuration): up to 96% removal of nitrate and nitrite, due to denitrification; low-specific biomass production (0.092 kgVSS kgCODremoved⁻¹), and biological treatability of residual COD under mesophilic conditions (BOD5/COD ratio = 0.25-0.50), thus showing the complementarity of the two biological processes.

Analysis of chemical reaction kinetics of depredating organic pollutants from secondary effluent of wastewater treatment plant in constructed wetlands.

PubMed

Wang, Hao; Jiang, Dengling; Yang, Yong; Cao, Guoping

2013-01-01

Four subsurface constructed wetlands were built to treat the secondary effluent of a wastewater treatment plant in Tangshan, China. The chemical pollutant indexes of chemical oxygen demand (COD) were analyzed to evaluate the removal efficiency of organic pollutants from the secondary effluent of the wastewater treatment plant. In all cases, the subsurface constructed wetlands were efficient in treating organic pollutants. Under the same hydraulic loading condition, the horizontal flow wetlands exhibited better efficiency of COD removal than vertical flow wetlands: the removal rates in horizontal flow wetlands could be maintained at 68.4 ± 2.42% to 92.2 ± 1.61%, compared with 63.8 ± 1.19% to 85.0 ± 1.25% in the vertical flow wetlands. Meanwhile, the chemical reaction kinetics of organic pollutants was analyzed, and the results showed that the degradation courses of the four subsurface wetlands all corresponded with the first order reaction kinetics to a large extent.

Treatment performance and microorganism community structure of integrated vertical-flow constructed wetland plots for domestic wastewater.

PubMed

Wu, Su-qing; Chang, Jun-jun; Dai, Yanran; Wu, Zhen-bin; Liang, Wei

2013-06-01

In order to investigate the treatment performance and microorganism mechanism of IVCW for domestic wastewater in central of China, two parallel pilot-scale IVCW systems were built to evaluate purification efficiencies, microbial community structure and enzyme activities. The results showed that mean removal efficiencies were 81.03 % for COD, 51.66 % for total nitrogen (TN), 42.50 % for NH4 (+)-N, and 68.01 % for TP. Significant positive correlations between nitrate reductase activities and TN and NH4 (+)-N removal efficiencies, along with a significant correlation between substrate enzyme activity and operation time, were observed. Redundancy analysis demonstrated gram-negative bacteria were mainly responsible for urease and phosphatase activities, and also played a major role in dehydrogenase and nitrate reductase activities. Meanwhile, anaerobic bacteria, gram-negative bacteria, and saturated FA groups, gram-positive bacteria exhibited good correlations with the removal of COD (p=0.388), N (p=0.236), and TP (p=0.074), respectively. The IVCW system can be used to treat domestic wastewater effectively.

Investigation of furfural biodegradation in a continuous inflow cyclic biological reactor.

PubMed

Moussavi, Gholamreza; Leili, Mostafa; Nadafi, Kazem

2016-01-01

The performance of a continuous inflow cyclic biological reactor (CBR) containing moving media was investigated for the degradation of high concentrations of furfural. The effects of hydraulic retention time (HRT) and furfural initial concentrations (loading rate), as main operating parameters, on the bioreactor performance were studied. The results indicated that the CBR could remove over 98% of furfural and 71% of its chemical oxygen demand (COD) at inlet furfural concentrations up to 1,200 mg L(-1) (2.38 g L(-1) d(-1)), a 6-h cycle time and HRT of 12.1 h. The removal efficiency decreased slightly from 98 to 94% when HRT decreased from 12.1 to 10.5 h. The average removal efficiency of furfural and COD during the 345-day operational period under steady-state conditions were 97.7% and 82.1%, respectively. The efficiency also increased approximately 17.2% after addition of synthetic polyurethane cubes as moving media at a filling ratio of 10%.

The use of food waste as a carbon source for on-site treatment of nutrient-rich blackwater from an office block.

PubMed

Tannock, Simon J C; Clarke, William P

2016-09-01

Wastewater from office blocks is typically dominated by blackwater and is therefore concentrated and nutrient-rich. A pilot plant was operated for 260 days, receiving 300 L d(-1) of wastewater directly from an office building to determine whether nutrient removal could be achieved using food waste (FW) as a supplemental carbon source. The pilot plant consisted of a 600 L prefermenter and a 600 L membrane bioreactor that was operated as a sequential batch reactor in order to cycle through anoxic, anaerobic and aerobic phases. The influent wastewater Chemical Oxygen Demand (COD)/N/P was, on average, 1438/275/40 mg L(-1), considerably higher than typical municipal wastewater. Treatment trials on the wastewater alone showed that the COD was only marginally sufficient to exhaust nitrate, and initiate anaerobic conditions required for phosphate removal. The addition of 15 kg d(-1) of macerated FW increased the average influent COD/N/P concentrations to 20,072/459/66 mg L(-1). The suitability of FW as a carbon source was demonstrated by denitrification to NOx-N concentration of <1 mg L(-1) during the biological nutrient removal (BNR) cycles. N removal was limited by nitrification. FW also induced the anaerobic phase within the BNR cycles necessary for P removal. The final average COD (non-recalcitrant)/N/P effluent concentrations under FW supplementation were 7/50/13 mg L(-1) which equates to 99%, 89% and 80% COD/N/P removal, respectively, meeting the highest nutrient removal efficiency standards stipulated by state jurisdictions for on-site systems in the USA.

Treatment of wastewater containing o-phenylenediamine by ozone in a rotor-stator reactor.

PubMed

Arowo, Moses; Li, Yingwen; Chu, Guangwen; Sun, Baochang; Chen, Jianfeng; Shao, Lei

2016-01-01

This work employed a novel rotor-stator reactor (RSR) to intensify the degradation process of o-phenylenediamine (o-PDA) by ozone. The effects of different operating parameters including initial pH, temperature, rotation speed, liquid volumetric flow rate and inlet ozone concentration on the removal efficiency of o-PDA were investigated in an attempt to establish the optimum conditions. The removal efficiency was evaluated in terms of degradation ratio and chemical oxygen demand (COD) reduction ratio of the o-PDA wastewater. Results indicate that the removal efficiency decreased with increasing liquid volumetric flow rate but increased with an increase in pH and inlet ozone concentration. Also, the removal efficiency increased up to a certain level with an increase in rotation speed and temperature. Additionally, a comparison experiment was carried out in a stirred tank reactor (STR), and the results show that the degradation and COD reduction ratios reached a maximum of 94.6% and 61.2% in the RSR as compared to 45.3% and 28.6% in the STR, respectively. This work demonstrates that ozone oxidation carried out in RSR may be a promising alternative for pre-treatment of o-PDA wastewater.

Effective swine wastewater treatment by combining microbial fuel cells with flocculation.

PubMed

Ding, Weijun; Cheng, Shaoan; Yu, Liliang; Huang, Haobin

2017-09-01

Microbial fuel cells (MFCs) provide a cost-effective method for treating swine wastewater treatment and simultaneously producing electricity, yet they need to be combined with other wastewater treatment processes to improve the effluent water quality. In this paper, we constructed single-chamber air-cathode MFCs with a compact configuration for nitrogen and COD removal and high electricity production and combined them with a low-cost flocculation process to discharge higher quality wastewater. We show that MFCs could remove ammonia at a rate of 269.2 ± 0.5 g m -3 d -1 (99.1± 0.1% ammonia removal efficiency) with a maximum power density of 37.5 W m -3 and 21.6% of coulombic efficiency at a 40:60 ratio of raw swine wastewater to denitrification effluent of swine wastewater. Up to 82.5 ± 0.5% COD could be removed with MFCs, from 2735 ± 15 mg L -1 to 480 ± 15 mg L -1 , and flocculation further reduced levels to 90 ± 1 mg L -1 for a 96.6 ± 0.2% overall COD removal efficiency of the combination technology. Cost analysis of the combined MFC and flocculation process showed a net economic benefit of $ 0.026 m -3 . In summary, this novel combination wastewater treatment method provides an effective way to treat swine wastewater to low pollutant levels in the effluent at low cost (a net gain). Copyright © 2017 Elsevier Ltd. All rights reserved.

Pollutant removal from oily wastewater discharged from car washes through sedimentation-coagulation.

PubMed

Rubí, H; Fall, C; Ortega, R E

2009-01-01

Wastewater from car washes represents a potential problem for the sewer system due to its emulsified oils and suspended material. Treatment of wastewater discharged from four car washes was investigated by sedimentation and coagulation. The effect of the coagulants Servical P (aluminium hydroxychloride), Servican 50 (poly(diallyldimethylammonium chloride)), aluminium sulfate and ferric chloride was evaluated. The achieved removal using sedimentation was of 82%, 88% 73% and 51% for oils, total suspended solids, COD, and turbidity, respectively. In the treatment by coagulation we achieved average efficiencies nearly to 74% for COD removal, greater than 88% in the case of total suspended solids removal and 92% in the case of turbidity and except the performance of Servican 50 greater than 90% in oil removal. We concluded that the oil residual concentration and COD in the treated water allows pouring it in the sewer system complying with the limits of the Mexican rule NOM-002-ECOL-1996 and it is possible even its reuse, at least in the case of the chassis washing of cars.

Microbial monitoring of ammonia removal in a UASB reactor treating pre-digested chicken manure with anaerobic granular inoculum.

PubMed

Yangin-Gomec, Cigdem; Pekyavas, Goksen; Sapmaz, Tugba; Aydin, Sevcan; Ince, Bahar; Akyol, Çağrı; Ince, Orhan

2017-10-01

Performance and microbial community dynamics in an upflow anaerobic sludge bed (UASB) reactor coupled with anaerobic ammonium oxidizing (Anammox) treating diluted chicken manure digestate (Total ammonia nitrogen; TAN=123±10mg/L) were investigated for a 120-d operating period in the presence of anaerobic granular inoculum. Maximum TAN removal efficiency reached to above 80% with as low as 20mg/L TAN concentrations in the effluent. Moreover, total COD (tCOD) with 807±215mg/L in the influent was removed by 60-80%. High-throughput sequencing revealed that Proteobacteria, Actinobacteria, and Firmicutes were dominant phyla followed by Euryarchaeota and Bacteroidetes. The relative abundance of Planctomycetes significantly increased from 4% to 8-9% during the late days of the operation with decreased tCOD concentration, which indicated a more optimum condition to favor ammonia removal through anammox route. There was also significant association between the hzsA gene and ammonia removal in the UASB reactor. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance and microbial community of anammox in presence of micro-molecule carbon source.

PubMed

He, Shilong; Yang, Wan; Qin, Meng; Mao, Zhen; Niu, Qigui; Han, Ming

2018-08-01

Because ammonium (NH 4 + -N) coexists with organic matter in some wastewaters, the possible adverse influences of organic matter become a major concern in the applications of anaerobic ammonium oxidation (anammox). In this study, the effects of acetate, as a representative of micro-molecule organic matter, on anammox were investigated. Efficient nitrogen removal was realized because denitrifying bacteria and anammox bacteria (AnAOB) had a better synergistic effect under the condition of chemical oxygen demand (COD) concentrations lower than 251 ± 7 mg L -1 . Furthermore, the nitrogen removal efficiency (NRE) decreased to 82.02 ± 3.14% when COD was increased to 730 ± 9 mg L -1 , and effluent free ammonia (FA) reached 21.93 ± 4.71 mg L -1 might be one of factors leading to inhibition. However, the nitrogen-removal contribution rate of anammox remained steady at 61.97 ± 2.84% at COD of 730 ± 9 mg L -1 , which indicated that anammox was still dominant in the system. AnAOB, such as Ca. Kuenenia and Ca. Jettenia, and denitrifying bacteria, such as Denitratisoma and Thauera, were found to coexist in the reactor. Interestingly, Ca. Kuenenia presented in the trend of first decreased then increased with the increasing of organic matter concentration, which might be one of reasons that anammox played an important role in nitrogen removal at high COD concentration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Performance of combined persulfate/aluminum sulfate for landfill leachate treatment.

PubMed

Abu Amr, Salem S; Alkarkhi, Abbas F M; Alslaibi, Tamer M; Abujazar, Mohammed Shadi S

2018-08-01

Although landfilling is still the most suitable method for solid waste disposal, generation of large quantity of leachate is still considered as one of the main environmental problem. Efficient treatment of leachate is required prior to final discharge. Persulfate (S 2 O 8 2- ) recently used for leachate oxidation, the oxidation potential of persulfate can be improved by activate and initiate sulfate radical. The current data aimed to evaluate the performance of utilizing Al 2 SO4 reagent for activation of persulfate to treat landfill leachate. The data on chemical oxygen demand (COD), color, and NH 3 -H removals at different setting of the persulfate, Al 2 SO 4 dosages, pH, and reaction time were collected using a central composite design (CCD) were measured to identify the optimum operating conditions. A total of 30 experiments were performed, the optimum conditions for S 2 O 8 2- /Al 2 SO 4 oxidation process was obtained. Quadratic models for chemical oxygen demand (COD), color, and NH 3 -H removals were significant with p-value < 0.0001. The experimental results were in agreement with the optimum results for COD and NH 3 -N removal rates to be 67%, 81%, and 48%, respectively). The results obtained in leachate treatment were compared with those from other treatment processes, such as S 2 O 8 2- only and Al 2 SO 4 only, to evaluate its effectiveness. The combined method (i.e., /S 2 O 8 2- /Al 2 SO 4 ) showed higher removal efficiency for COD, color, and NH 3 -N compared with other studied applications.

Use of Ceramic Membranes in a Membrane Filtration Supported by Coagulation for the Treatment of Dairy Wastewater.

PubMed

Zielińska, Magdalena; Galik, Maciej

2017-01-01

A membrane filtration system was used to remove organic compounds, suspended solids, colour and turbidity from anaerobically treated dairy wastewater. Direct microfiltration (MF), ultrafiltration (UF), MF-UF and a combination of UF with coagulation using two conventional coagulants were investigated. The installation with ceramic membranes was operated at a pressure of 0.15 MPa (MF) and 0.3 MPa (UF). COD removal was 89 ± 2% in MF, 95 ± 1% in UF and 99% in MF-UF. Apart from size exclusion, removal was also the result of adsorption of organics on the membrane; 3-18% of COD removal was attributed to adsorption. In all these membrane systems, colour removal was 96-98%. Coagulation removed 63-72% of COD at all coagulant doses. In combination with UF, 96-97% of COD was removed. The use of coagulants was ineffective for colour removal; further treatment by UF resulted in above 98% removal. Because of complete rejection of suspended solids, turbidity removal exceeded 99% under all conditions. The use of increased coagulant doses did not have an effect on total efficiency of pollutant removal and on the permeate flux. Coagulation pre-treatment enhanced the performance of filtration only by lengthening the filtration cycle by about 12% as compared to direct UF. Not only was pollutant removal highest in MF-UF, but also the average permeate flux was about 80% higher in this two-stage system than in direct UF. This study shows that the most effective strategy to mitigate membrane fouling is the use of MF as a pre-treatment preceding UF.

Anaerobic digestion of municipal wastewater sludges using anaerobic fluidized bed bioreactor.

PubMed

Mustafa, Nizar; Elbeshbishy, Elsayed; Nakhla, George; Zhu, Jesse

2014-11-01

The anaerobic digestion of primary sludge (PS) and thickened waste activated sludge (TWAS) using an anaerobic fluidized bed bioreactor (AnFBR) employing zeolite particles as the carrier media was investigated at different organic loading rates (OLRs). PS was tested at OLRs from 4.2 to 39kgCOD/m(3)-d corresponding to hydraulic retention times (HRTs) from 1.0 to 8.9days. The highest COD removal and VSS destruction efficiencies for primary sludge of 85% and 88%, respectively, were achieved at an HRT of 8.9days and OLR of 4.2kgCOD/m(3)-d. For TWAS, VSS destruction efficiencies varied from 42% at an HRT of 2.6days and OLR of 13.1kgCOD/m(3)-d to 69% at an HRT of 8.8days and an OLR of 4.2kgCOD/m(3)-d. The first-order COD biodegradation rates in the AnFBR for PS and TWAS were 0.4d(-1) and 0.1d(-1), respectively, almost double the rates in conventional high-rate digesters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of a high-strength sulphate-rich alkaline leachate using an anaerobic filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Z.; Banks, C.J.

2007-07-01

The research looks at the feasibility of treating an alkaline sulphate-rich leachate arising from the co-disposal of municipal solid waste with cement kiln dust by means of an anaerobic filter (AF). This type of leachate with a high sulphate concentration is commonly prohibited for discharge to sewer and requires an on-site treatment solution. The AF used had a working volume of 4 l and contained reticulated polyurethane foam as the biomass support material. The filters were operated over a 152 day experimental period during which the COD loading onto the filter was increased from 0.76 to 7.63 kg COD m{supmore » -3} d{sup -1}. In the early stages of operation at low loading, soluble sulphides accumulated that inhibited methanogenic activity. This was restored by dosing FeCl{sub 3} to the reactor. The continued dosing allowed efficient COD removal of between 75% and 90% until the nominal retention time in the reactor was 3 days, at which point reactor performance declined significantly. The main mechanism for COD removal was by sulphate-reducing bacteria, which also resulted in up to 88% sulphate removal from the leachate. The average methane generation rate was 0.10 l g{sup -1} COD removed. The results indicate the potential for using this approach as a pre-treatment that could significantly reduce the COD load to a second stage treatment process, but problems associated with the implementation of the technology at a larger scale have been identified.« less

Effect of activated sludge culture conditions on Waxberry wastewater

NASA Astrophysics Data System (ADS)

Shi, Liang; He, Lingfeng; Zhang, Yongli

2018-03-01

Treated activated sludge is suitable for the treatment of wastewater. Biochemical method is used to treat the wastewater, and the influence of time on the COD index is investigated. The results showed that time had a significant effect on COD, and then affected the performance of activated sludge. Under different time, according to the order of time from short to long, COD decreases in turn. Under the action of activated sludge, the degradation of myrica rubra wastewater samples, after 25 h aeration for 96 h, the effect is better. Under this condition, the COD value was reduced at 72 mg/L, and the COD removal efficiency of myrica rubra wastewater was up to 93.39 %, and reached the two level discharge standard of municipal wastewater treatment.

Flocculent Settling of Food Wastes.

PubMed

Chowdhury, Mohammad Monirul Islam; Kim, Mingu; Haroun, Basem Mikhaeil; Nakhla, George; Keleman, Michael

2016-07-01

This study evaluated the flocculent settling in water and municipal wastewater (MWW) in a 10.6 ft deep column. A total of eight runs at three different testing conditions involving MWW alone, food waste (FW) alone, and FW in MWW (FW+MWW) were conducted. Total suspended solid (TSS), total BOD (TBOD), total COD (TCOD), total nitrogen (TN), and total phosphorous (TP) removal efficiencies after 3 hours of settling were 62%, 46%, 49%, 46% and 62% for FW, and 50%, 43%, 39%, 37% and 24% for MWW. Removal efficiencies of particulate COD (PCOD) and particulate BOD (PBOD) at the lowest surface overflow rate (SOR) of 1.1 m3/m2/hr corresponding to the longest settling time of 3 hours were 59% and 64% for FW, and 65% and 70% for FW with MWW samples. On the other hand, no significant variation between FW and FW with MWW was observed for PN removal after 3 hours of settling.

Photocatalytic pretreatment of oily wastewater from the restaurant by a vacuum ultraviolet/TiO2 system.

PubMed

Kang, Jian-xiong; Lu, Lu; Zhan, Wei; Li, Bo; Li, Dao-sheng; Ren, Yong-zheng; Liu, Dong-qi

2011-02-15

The present study aims at investigating the performance of a vacuum ultraviolet (VUV, 185 nm) and TiO(2) oxidation system for the pretreatment of oily wastewater from restaurant. The influence of irradiation time, pH, dissolved oxygen (DO), the dosage of TiO(2) and the initial chemical oxygen demand (COD) concentration on COD removal efficiency was ascertained and optimum process conditions for stable and effective operation were determined. Under the optimum conditions of irradiation 10 min, initial COD 3981 mg/L, TiO(2) 150 mg/L, pH 7.0 and flow rate of air 40 L/h, the process of VUV and TiO(2)/VUV achieved removal efficiencies of COD, BOD(5) and oil as 50±3%, 37±2%, 86±3%, and 63±3%, 43±2%, 70±3%, respectively. The biodegradability factor f(B) of the wastewater was determined as 1.56 which indicated that the VUV/TiO(2) process improved the biodegradability of the oily wastewater significantly. Results clearly indicate that VUV/TiO(2) photolysis tends to destruct parts of COD, BOD(5), and ammonia, as well as enhances the biodegradability of the oily wastewater simultaneously. Thus, this technique could be used as a pretreatment step for conventional biological treatment of oily wastewater. Copyright © 2010 Elsevier B.V. All rights reserved.

Addition of anaerobic tanks to an oxidation ditch system to enhance removal of phosphorus from wastewater.

PubMed

Liu, Jun-xin; van Groenestijn, J W; Doddema, H J; Wang, Bao-zhen

2002-04-01

The oxidation ditch has been used for many years all over the world as an economic and efficient wastewater treatment technology. It can remove COD, nitrogen and a part of phosphorus efficiently. In the experiment described, a pilot scale Pasveer oxidation ditch system has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that influent total phosphorus(TP) was removed for 35%-50%. After this, two anaerobic tanks with total volume of 11 m3 were added to the system to release phosphorus. As a result, the TP removal efficiency increased by about 20%. At an anaerobic HRT of about 6 hours, a TP removal efficiency of 71% was achieved.

Simultaneous carbon and nitrogen removal from anaerobic effluent of the cassava ethanol industry.

PubMed

Yin, Zhixuan; Xie, Li; Zhou, Qi; Bi, Xuejun

2018-03-01

This study investigated the simultaneous carbon and nitrogen removal from anaerobic effluent of cassava stillage using a lab-scale integrated system consisting of an upflow anaerobic sludge blanket (UASB) reactor and an activated sludge (AS) process. Simultaneous denitrification and methanogenesis (SDM) was observed in the UASB with nitrate recirculation. Compared with the blank reactor without recirculation, the overall chemical oxygen demand (COD) removal efficiencies in the combined system with nitrate recirculation were similar (80-90%), while the TN removal efficiencies were significantly improved from 4.7% to 71.0%. Additionally, the anaerobic COD removal efficiencies increased from 21% to 40% as the recirculation ratio decreased from 3 to 1. Although the influent nitrate concentrations fluctuated (60-140 mg N/L), the nitrate removal efficiencies could be maintained at about 97% under different recirculation conditions. With the decreasing recirculation ratio from 3 to 1, the CH 4 content in biogas improved from 2% to 40% while the N 2 content reduced from 95.8% to 50.6%. The 16S rDNA sequencing results indicated that bacteria diversity in anaerobic SDM granular sludge was much higher than archaea. The effect of recirculation ratios on the bacterial and archaeal communities in SDM granular sludge could be further confirmed by the relative abundance of denitrifying bacteria. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

The removal efficiency of constructed wetlands filled with the zeolite-slag hybrid substrate for the rural landfill leachate treatment.

PubMed

He, Hailing; Duan, Zhiwei; Wang, Zhenqing; Yue, Bo

2017-07-01

The removal efficiencies of two horizontal subsurface flow constructed wetlands (HSSF CWs, down-flow (F1) and up-flow (F2)) filled with the zeolite-slag hybrid substrate for the rural landfill leachate treatment were investigated. The adsorption experiment was conducted to evaluate the potential of zeolite and slag as the wetland substrate. The effects of distance variations along the longitudinal profile of wetland bed on pollutant removal were assessed by sampling at four locations (inlet, outlet, 0.55 m, and 1.10 m from the inlet). During the operation time, the influent and effluent concentrations of chemical oxygen demand (COD), ammonia nitrogen (NH 3 -N), total nitrogen (TN), heavy metals, and polycyclic aromatic hydrocarbon (PAH) were measured. The results showed that the constructed wetlands were capable of removing COD, 20.5-48.2% (F1) and 18.6-61.2% (F2); NH 3 -N, 84.0-99.9% (F1) and 93.5-99.2% (F2); TN, 80.3-92.1% (F1) and 80.3-91.2% (F2); and heavy metals, about 90% (F1 and F2). The zeolite-slag hybrid substrate performed excellent removal efficiency for the nitrogen and heavy metals. The inlet area was the most active region of leachate removal. The up-flow constructed wetland (F2) has a higher removal efficiency for the PAH compounds. The significant removal efficiency illustrated that the rural landfill leachate can be treated using the horizontal subsurface flow constructed wetland filled with the zeolite-slag hybrid substrate.

Upflow bio-filter circuit (UBFC): biocatalyst microbial fuel cell (MFC) configuration and application to biodiesel wastewater treatment.

PubMed

Sukkasem, Chontisa; Laehlah, Sunee; Hniman, Adilan; O'thong, Sompong; Boonsawang, Piyarat; Rarngnarong, Athirat; Nisoa, Mudtorlep; Kirdtongmee, Pansak

2011-11-01

A biodiesel wastewater treatment technology was investigated for neutral alkalinity and COD removal by microbial fuel cell. An upflow bio-filter circuit (UBFC), a kind of biocatalyst MFC was renovated and reinvented. The developed system was combined with a pre-fermented (PF) and an influent adjusted (IA) procedure. The optimal conditions were operated with an organic loading rate (OLR) of 30.0 g COD/L-day, hydraulic retention time (HRT) of 1.04 day, maintained at pH level 6.5-7.5 and aerated at 2.0 L/min. An external resistance of circuit was set at 10 kΩ. The purposed process could improve the quality of the raw wastewater and obtained high efficiency of COD removal of 15.0 g COD/L-day. Moreover, the cost of UBFC system was only US$1775.7/m3 and the total power consumption was 0.152 kW/kg treated COD. The overall advantages of this invention are suitable for biodiesel wastewater treatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparison of laboratory-scale thermophilic biofilm and activated sludge processes integrated with a mesophilic activated sludge process.

PubMed

Suvilampi, J; Lehtomäki, A; Rintala, J

2003-07-01

A combined thermophilic-mesophilic wastewater treatment was studied using a laboratory-scale thermophilic activated sludge process (ASP) followed by mesophilic ASP or a thermophilic suspended carrier biofilm process (SCBP) followed by mesophilic ASP, both systems treating diluted molasses (dilution factor 1:500 corresponding GF/A-filtered COD (COD(filt)) of 1900+/-190 mgl(-1)). With hydraulic retention times (HRTs) of 12-18 h the thermophilic ASP and thermophilic SCBP removed 60+/-13% and 62+/-7% of COD(filt), respectively, with HRT of 8 h the removals were 48+/-1% and 69+/-4%. The sludge volume index (SVI) was notably lower in the thermophilic SCBP (measured from suspended sludge) than in the thermophilic ASP. Under the lowest HRT the mesophilic ASP gave better performance (as SVI, COD(filt), and COD(tot) removals) after the thermophilic SCBP than after the thermophilic ASP. Measured sludge yields were low (less than 0.1 kg suspended solids (SS) kg COD(filt removed)(-1)) in all processes. Both thermophilic treatments removed 80-85% of soluble COD (COD(sol)) whereas suspended COD (COD(susp)) and colloidal COD (COD(col)) were increased. Both mesophilic post-treatments removed all COD(col) and most of the COD(susp) from the thermophilic effluents. In conclusion, combined thermophilic-mesophilic treatment appeared to be easily operable and produced high effluent quality.

Denitrifying bioreactor clogging potential during wastewater treatment.

PubMed

Christianson, Laura E; Lepine, Christine; Sharrer, Kata L; Summerfelt, Steven T

2016-11-15

Chemoheterotrophic denitrification technologies using woodchips as a solid carbon source (i.e., woodchip bioreactors) have been widely trialed for treatment of diffuse-source agricultural nitrogen pollution. There is growing interest in the use of this simple, relatively low-cost biological wastewater treatment option in waters with relatively higher total suspended solids (TSS) and chemical oxygen demand (COD) such as aquaculture wastewater. This work: (1) evaluated hydraulic retention time (HRT) impacts on COD/TSS removal, and (2) assessed the potential for woodchip clogging under this wastewater chemistry. Four pilot-scale woodchip denitrification bioreactors operated for 267 d showed excellent TSS removal (>90%) which occurred primarily near the inlet, and that COD removal was maximized at lower HRTs (e.g., 56% removal efficiency and 25 g of COD removed per m 3 of bioreactor per d at a 24 h HRT). However, influent wastewater took progressively longer to move into the woodchips likely due to a combination of (1) woodchip settling, (2) clogging due to removed wastewater solids and/or accumulated bacterial growth, and (3) the pulsed flow system pushing the chips away from the inlet. The bioreactor that received the highest loading rate experienced the most altered hydraulics. Statistically significant increases in woodchip P content over time in woodchip bags placed near the bioreactor outlets (0.03 vs 0.10%P 2 O 5 ) and along the bioreactor floor (0.04 vs. 0.12%P 2 O 5 ) confirmed wastewater solids were being removed and may pose a concern for subsequent nutrient mineralization and release. Nevertheless, the excellent nitrate-nitrogen and TSS removal along with notable COD removal indicated woodchip bioreactors are a viable water treatment technology for these types of wastewaters given they are used downstream of a filtration device. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Removal of slowly biodegradable COD in combined thermophilic UASB and MBBR systems.

PubMed

Ji, M; Yu, J; Chen, H; Yue, P L

2001-09-01

Starch, cellulose and polyvinyl alcohol (PVA) are common substrates of the slowly biodegradable COD (SBCOD) in industrial wastewaters. Removal of the individual and mixed SbCOD substrates was investigated in a combined system of thermophilic upflow anaerobic sludge blanket (TUASB) reactor (55 degrees C) and aerobic moving bed biofilm reactor (MBBR). The removal mechanisms of the three SBCOD substrates were quite different. Starch-COD was almost equally utilized and removed in the two reactors. Cellulose-COD was completely (97-98%) removed from water in the TUASB reactor by microbial entrapment and sedimentation of the cellulose fibers. PVA alone was hardly biodegraded and removed by the combined reactors. However, PVA-COD could be removed to some extent in a binary solution of starch (77%) plus PVA (23%). The PVA macromolecules in the binary solution actually affected the microbial activity in the TUASB reactor resulting accumulation of volatile fatty acids, which shifted the overall COD removal from the TUASB to the MBBR reactor where SBCOD including PVA-COD was removed. Since the three SBCOD substrates were removed by different mechanisms, the combined reactors showed a better and more stable performance than individual reactors.

Removal of nutrients in denitrification system using coconut coir fibre for the biological treatment of aquaculture wastewater.

PubMed

Manoj, Valsa Remony; Vasudevan, Namasivayam

2012-03-01

Ideal bacterial support medium for fixed film denitrification processes/bioreactors must be inexpensive, durable and possess large surface area with sufficient porosity. The present study has been focussed on removing nitrate nitrogen at two different nitrate nitrogen loading rates (60 (NLR I) and 120 (NLR II) mg l(-1)) from simulated aquaculture wastewater. Coconut coir fibre and a commercially available synthetic reticulated plastic media (Fujino Spirals) were used as packing medium in two independent upflow anaerobic packed bed column reactors. Removal of nitrate nitrogen was studied in correlation with other nutrients (COD, TKN, dissolved orthophosphate). Maximum removal of 97% at NLR-I and 99% at NLR - II of nitrate nitrogen was observed in with either media. Greater consistency in the case of COD removal of upto 81% was observed at NLR II where coconut coir was used as support medium compared to 72% COD removal by Fujino Spirals. The results observed indicate that the organic support medium is just as efficient in nitrate nitrogen removal as conventionally used synthetic support medium. The study is important as it specifically focuses on denitrification of aquaculture wastewater using cheaper organic support medium in anoxic bioreactors for the removal of nitrate nitrogen; which is seldom addressed as a significant problem.

Sequential hydrogen and methane coproduction from sugary wastewater treatment by "CSTRHyd-UASBMet" system

NASA Astrophysics Data System (ADS)

Hao, Ping

2017-10-01

Potentiality of sequential hydrogen bioproduction from sugary wastewater treatment was investigated using continuous stirred tank reactor (CSTR) for various substrate COD concentrations and HRTs. At optimum substrate concentration of 6 g COD/L, hydrogen could be efficiently produced from CSTR with the highest production rate of 3.00 (±0.04) L/L reactor d at HRT of 6 h. The up flow anaerobic sludge bed (UASB) reactor was used for continuous methane bioproduction from the effluents of hydrogen bioproduction. At optimal HRT 12 h, methane could be produced with a production rate of 2.27 (±0.08) L/L reactor d and the COD removal efficiency reached up to the maximum 82.3%.

Variables affecting efficiency of molasses fermentation wastewater ozonation.

PubMed

Coca, M; Peña, M; González, G

2005-09-01

The main operating variables affecting ozonation efficiencies of wastewater from beet molasses alcoholic fermentation have been studied. Semibatch experiments have been performed in order to analyze the influence of pH, bicarbonate ion, temperature and stirring rate on color and organic matter removals. The efficiencies were similar regardless of the pH, which indicates that direct reactions of ozone with wastewater organics were predominant to radical reactions. Gel permeation chromatography confirmed the reduction in the concentration of organics absorbing light at 475 nm after ozonation. The elimination of bicarbonate ion, strong inhibitor of hydroxyl radical reactions, yielded an improvement in both color and COD reduction efficiencies. Acidification for removing bicarbonate ions produced a shift of colored compounds to smaller molecular weights. The highest efficiencies were achieved at 40 degrees C. Color and COD reductions at 40 degrees C were about 90% and 37%, respectively. In no case, the percentage of TOC removed was higher than 10-15%. Stirring rate had a slightly positive effect during the first stage of the ozonation showing that mass transfer played a role only during the initial reaction phase when direct attack of ozone molecules to aromatic/olefinic structures of colored substances was the predominant pathway.

Ultrasonic sludge disintegration for enhanced methane production in anaerobic digestion: effects of sludge hydrolysis efficiency and hydraulic retention time.

PubMed

Kim, Dong-Jin; Lee, Jonghak

2012-01-01

Hydrolysis of waste activated sludge (WAS) has been regarded as the rate limiting step of anaerobic sludge digestion. Therefore, in this study, the effect of ultrasound and hydraulic residence time during sludge hydrolysis was investigated with the goal of enhancing methane production from anaerobic digestion (AD). WAS was ultrasonically disintegrated for hydrolysis, and it was semi-continuously fed to an anaerobic digesters at various hydraulic retention times (HRTs). The results of these experiments showed that the solids and chemical oxygen demand (COD) removal efficiencies when using ultrasonically disintegrated sludge were higher during AD than the control sludge. The longer the HRT, the higher the removal efficiencies of solids and COD, while methane production increased with lower HRT. Sludge with 30% hydrolysis produced 7 × more methane production than the control sludge. The highest methane yields were 0.350 m(3)/kg volatile solids (VS)(add) and 0.301 m(3)/kg COD(con) for 16 and 30% hydrolyzed sludge, respectively. In addition, we found that excess ultrasound irradiation may inhibit AD since the 50% hydrolyzed sludge produced lower methane yields than 16 and 30% hydrolyzed sludge.

Optimization of conventional Fenton and ultraviolet-assisted oxidation processes for the treatment of reverse osmosis retentate from a paper mill.

PubMed

Hermosilla, Daphne; Merayo, Noemí; Ordóñez, Ruth; Blanco, Angeles

2012-06-01

According to current environmental legislation concerned with water scarcity, paper industry is being forced to adopt a zero liquid effluent policy. In consequence, reverse osmosis (RO) systems are being assessed as the final step of effluent treatment trains aiming to recover final wastewater and reuse it as process water. One of the most important drawbacks of these treatments is the production of a retentated stream, which is usually highly loaded with biorecalcitrant organic matter and inorganics; and this effluent must meet current legislation stringent constraints before being ultimately disposed. The treatment of biorefractory RO retentate from a paper mill by several promising advanced oxidation processes (AOPs) - conventional Fenton, photo-Fenton and photocatalysis - was optimized considering the effect and interaction of reaction parameters; particularly using response surface methodology (RSM) when appropriate (Fenton processes). The economical cost of these treatments was also comparatively assessed. Photo-Fenton process was able to totally remove the COD of the retentate, and resulted even operatively cheaper at high COD removal levels than conventional Fenton, which achieved an 80% reduction of the COD at best. In addition, although these optimal results were produced at pH=2.8, it was also tested that Fenton processes are able to achieve good COD reduction efficiencies (>60%) without adjusting the initial pH value, provided the natural pH of this wastewater was close to neutral. Finally, although TiO(2)-photocatalysis showed the least efficient and most expensive figures, it improved the biodegradability of the retentate, so its combination with a final biological step almost achieved the total removal of the COD. Copyright © 2011 Elsevier Ltd. All rights reserved.

Multi-phased anaerobic baffled reactor treating food waste.

PubMed

Ahamed, A; Chen, C-L; Rajagopal, R; Wu, D; Mao, Y; Ho, I J R; Lim, J W; Wang, J-Y

2015-04-01

This study was conducted to identify the performance of a multi-phased anaerobic baffled reactor (MP-ABR) with food waste (FW) as the substrate for biogas production and thereby to promote an efficient energy recovery and treatment method for the wastes with high organic solid content through phase separation. A four-chambered ABR was operated at an HRT of 30 days with an OLR of 0.5-1.0 g-VS/Ld for a period of 175 days at 35 ± 1°C. Consistent overall removal efficiencies of 85.3% (CODt), 94.5% (CODs), 89.6% (VFA) and 86.4% (VS) were observed throughout the experiment displaying a great potential to treat FW. Biogas generated was 215.57 mL/g-VS removed d. Phase separation was observed and supported by the COD and VFA trends, and an efficient recovery of bioenergy from FW was achieved. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nitrogen removal from high organic loading wastewater in modified Ludzack-Ettinger configuration MBBR system.

PubMed

Torkaman, Mojtaba; Borghei, Seyed Mehdi; Tahmasebian, Sepehr; Andalibi, Mohammad Reza

2015-01-01

A moving bed biofilm reactor with pre-denitrification configuration was fed with a synthetic wastewater containing high chemical oxygen demand (COD) and ammonia. By changing different variables including ammonium and COD loading, nitrification rate in the aerobic reactor and denitrification rate in the anoxic reactor were monitored. Changing the influent loading was achieved via adjusting the inlet COD (956-2,096 mg/L), inlet ammonium (183-438 mg/L), and hydraulic retention time of the aerobic reactor (8, 12, and 18 hours). The overall organic loading rate was in the range of 3.60-17.37 gCOD/m2·day, of which 18.5-91% was removed in the anoxic reactor depending on the operational conditions. Considering the complementary role of the aerobic reactor, the overall COD removal was in the range 87.3-98.8%. In addition, nitrification rate increased with influent ammonium loading, the maximum rate reaching 3.05 gNH4/m2·day. One of the most important factors affecting nitrification rate was influent C:N entering the aerobic reactor, by increasing which nitrification rate decreased asymptotically. Nitrate removal efficiency in the anoxic reactor was also controlled by the inlet nitrate level entering the anoxic reactor. Furthermore, by increasing the nitrate loading rate from 0.91 to 3.49 gNO/m3·day, denitrification rate increased from 0.496 to 2.47 gNO/m3·day.

Nitrogen and COD removal from domestic and synthetic wastewater in subsurface-flow constructed wetlands.

PubMed

Collison, R S; Grismer, M E

2013-09-01

Comparisons of the performance of constructed-wetland systems (CWs) for treating domestic wastewater in the laboratory and field may use pathogen-free synthetic wastewater to avoid regulatory health concerns. However, little to no data are available describing the relative treatment efficiencies of CWs to both actual and synthetic domestic wastewaters so as to enable such comparison. To fill this gap, treatment performances with respect to organics (chemical organic demand; COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) and a similar-strength synthetic wastewater under planted and non-planted subsurface-flow CWs are determined. One pair of CWs was planted with cattails in May 2008, whereas the adjacent system was non-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each CWs, and effluent samples were collected and tested for COD and nitrogen species regularly during four different periods over six months. Overall, statistically significant greater removal of COD (-12%) and nitrogen (-5%) occurred from the synthetic as compared with the domestic wastewater from the planted and non-planted CWs. Effluent BOD5/COD ratios from the synthetic wastewater CWs averaged nearly twice that from the domestic wastewater CWs (0.17 vs 0.10), reflecting greater concentrations of readily degraded compounds. That removal fractions were consistent across the mid-range loading rates to the CWs suggests that the synthetic wastewater can be used in testing laboratory CWs with reasonable success in application of their results to the field.

Simultaneous wastewater treatment and biogas production using integrated anaerobic baffled reactor granular activated carbon from baker's yeast wastewater.

PubMed

Pirsaheb, Meghdad; Mohamadi, Samira; Rahmatabadi, Sama; Hossini, Hooshyar; Motteran, Fabrício

2017-08-30

In this study, simultaneous degradation of organic matter and color removal from food processing industries wastewater using an integrated anaerobic baffled reactor granular activated carbon (IABRGAC) was investigated. Theretofore, effective parameters such as hydraulic retention time (HRT) and granular activated carbon (GAC) filling ratio were studied. The bioreactor was operated at 3, 4 and 5 d of HRT and GAC filling ratio of 20%, 35% and 50%. To analyze and optimize the independent operating variables, response surface methodology was applied. Operating condition was optimized for HRT (4 d) and GAC filling ratio (50%). Better COD (94.6%) and BOD (93.7%) removal efficiency occurred with loading COD of 15,000 mg/L, with diminished wastewater color around 54% and turbidity to 54 NTU. In addition, methane production, methane yielding rate (Y m ) and specific methanogenic activity (SMA) test in an integrated system were investigated. The system IABRGAC was able to generate a volumetric rate about 0.31 and 0.44 L/g COD removed d at the experimental condition. The Y m was between 0.31 and 0.44 L/g COD removed .d and SMA was between 0.13 and 0.38 g COD/g volatile suspended solid. Based on results it can be concluded that the IABRGAC to be a successful pretreatment for highstrength wastewater before discharging the final effluent to sewerage and aerobic treating processes.

SBR treatment of olive mill wastewaters: dilution or pre-treatment?

PubMed

Farabegoli, G; Chiavola, A; Rolle, E

2012-01-01

The olive-oil extraction industry is an economically important activity for many countries of the Mediterranean Sea area, with Spain, Greece and Italy being the major producers. This activity, however, may represent a serious environmental problem due to the discharge of highly polluted effluents, usually referred to as 'olive mill wastewaters' (OMWs). They are characterized by high values of chemical oxygen demand (COD) (80-300 g/L), lipids, total polyphenols (TPP), tannins and other substances difficult to degrade. An adequate treatment before discharging is therefore required to reduce the pollutant load. The aim of the present paper was to evaluate performances of a biological process in a sequencing batch reactor (SBR) fed with pre-treated OMWs. Pre-treatment consisted of a combined acid cracking (AC) and granular activated carbon (GAC) adsorption process. The efficiency of the system was compared with that of an identical SBR fed with the raw wastewater only diluted. Combined AC and GAC adsorption was chosen to be used prior to the following biological process due to its capability of providing high removal efficiencies of COD and TPP and also appreciable improvement of biodegradability. Comparing results obtained with different influents showed that best performances of the SBR were obtained by feeding it with raw diluted OMWs (dOMWs) and at the lowest dilution ratio (1:25): in this case, the removal efficiencies were 90 and 76%, as average, for COD and TPP, respectively. Feeding the SBR with either the pre-treated or the raw dOMWs at 1:50 gave very similar values of COD reduction (74%); however, an improvement of the TPP removal was observed in the former case.

Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

PubMed

Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

2014-04-01

A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Aerobic granules formation and nutrients removal characteristics in sequencing batch airlift reactor (SBAR) at low temperature.

PubMed

Bao, Ruiling; Yu, Shuili; Shi, Wenxin; Zhang, Xuedong; Wang, Yulan

2009-09-15

To understand the effect of low temperature on the formation of aerobic granules and their nutrient removal characteristics, an aerobic granular sequencing batch airlift reactor (SBAR) has been operated at 10 degrees C using a mixed carbon source of glucose and sodium acetate. The results showed that aerobic granules were obtained and that the reactor performed in stable manner under the applied conditions. The granules had a compact structure and a clear out-surface. The average parameters of the granules were: diameter 3.4mm, wet density 1.036 g mL(-1), sludge volume index 37 mL g(-1), and settling velocity 18.6-65.1 cm min(-1). Nitrite accumulation was observed, with a nitrite accumulation rate (NO(2)(-)-N/NO(x)(-)-N) between 35% and 43% at the beginning of the start-up stage. During the stable stage, NO(x) was present at a level below the detection limit. However, when the influent COD concentration was halved (resulting in COD/N a reduction of the COD/N from 20:1 to 10:1) nitrite accumulation was observed once more with an effluent nitrite accumulation rate of 94.8%. Phosphorus release was observed in the static feeding phase and also during the initial 20-30 min of the aerobic phase. Neither the low temperature nor adjustment of the COD/P ratio from 100:1 to 25:1 had any influence on the phosphorus removal efficiency under the operating conditions. In the granular reactor with the influent load rates for COD, NH(4)(+)-N, and PO(4)(3-)-P of 1.2-2.4, 0.112 and 0.012-0.024 kg m(-3)d(-1), the respective removal efficiencies at low temperature were 90.6-95.4%, 72.8-82.1% and 95.8-97.9%.

Fine-tuning key parameters of an integrated reactor system for the simultaneous removal of COD, sulfate and ammonium and elemental sulfur reclamation.

PubMed

Yuan, Ye; Chen, Chuan; Liang, Bin; Huang, Cong; Zhao, Youkang; Xu, Xijun; Tan, Wenbo; Zhou, Xu; Gao, Shuang; Sun, Dezhi; Lee, Duujong; Zhou, Jizhong; Wang, Aijie

2014-03-30

In this paper, we proposed an integrated reactor system for simultaneous removal of COD, sulfate and ammonium (integrated C-S-N removal system) and investigated the key parameters of the system for a high level of elemental sulfur (S(0)) production. The system consisted of 4 main units: sulfate reduction and organic carbon removal (SR-CR), autotrophic and heterotrophic denitrifying sulfide removal (A&H-DSR), sulfur reclamation (SR), and aerated filter for aerobic nitrification (AN). In the system, the effects of key operational parameters on production of elemental sulfur were investigated, including hydraulic retention time (HRT) of each unit, sulfide/nitrate (S(2-)-S/NO3(-)-N) ratios, reflux ratios between the A&H-DSR and AN units, and loading rates of chemical oxygen demand (COD), sulfate and ammonium. Physico-chemical characteristics of biosulfur were studied for acquiring efficient S(0) recovery. The experiments successfully explored the optimum parameters for each unit and demonstrated 98% COD, 98% sulfate and 78% nitrogen removal efficiency. The optimum HRTs for SR-CR, A&H-DSR and AN were 12h, 3h and 3h, respectively. The reflux ratio of 3 could provide adequate S(2-)-S/NO3(-)-N ratio (approximately 1:1) to the A&H-DSR unit for obtaining maximum sulfur production. In this system, the maximum production of S(0) reached 90%, but only 60% S(0) was reclaimed from effluent. The S(0) that adhered to the outer layer of granules was deposited in the bottom of the A&H-DSR unit. Finally, the microbial community structure of the corresponding unit at different operational stage were analyzed by 16S rRNA gene based high throughput Illumina MiSeq sequencing and the potential function of dominant species were discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Assessment of coagulation pretreatment of leachate by response surface methodology.

PubMed

Lessoued, Ridha; Souahi, Fatiha; Castrillon Pelaez, Leonor

2017-11-01

Coagulation-flocculation is a relatively simple technique that can be used successfully for the treatment of old leachate by poly-aluminum chloride (PAC). The main objectives of this study are to design the experiments, build models and optimize the operating parameters, dosage m and pH, using the central composite design and response surface method. Developed for chemical organic matter (COD) and turbidity responses, the quadratic polynomial model is suitable for prediction within the range of simulated variables as it showed that the optimum conditions were m of 5.55 g/L at pH 7.05, with a determination coefficient R² at 99.33%, 99.92% and adjusted R² at 98.85% and 99.86% for both COD and turbidity. We confirm that the initial pH and PAC dosage have significant effects on COD and turbidity removal. The experimental data and model predictions agreed well and the removal efficiency of COD, turbidity, Fe, Pb and Cu reached respectively 61%, 96.4%, 97.1%, 99% and 100%.

Hydrogen production from continuous flow, microbial reverse-electrodialysis electrolysis cells treating fermentation wastewater.

PubMed

Watson, Valerie J; Hatzell, Marta; Logan, Bruce E

2015-11-01

A microbial reverse-electrodialysis electrolysis cell (MREC) was used to produce hydrogen gas from fermentation wastewater without the need for additional electrical energy. Increasing the number of cell pairs in the reverse electrodialysis stack from 5 to 10 doubled the maximum current produced from 60 A/m(3) to 120 A/m(3) using acetate. However, more rapid COD removal required a decrease in the anolyte hydraulic retention time (HRT) from 24 to 12 h to stabilize anode potentials. Hydrogen production using a fermentation wastewater (10 cell pairs, HRT=8 h) reached 0.9±0.1 L H2/Lreactor/d (1.1±0.1 L H2/g-COD), with 58±5% COD removal and a coulombic efficiency of 74±5%. These results demonstrated that consistent rates of hydrogen gas production could be achieved using an MREC if effluent anolyte COD concentrations are sufficient to produce stable anode potentials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Start-up, steady state performance and kinetic evaluation of a thermophilic integrated anaerobic-aerobic bioreactor (IAAB).

PubMed

Chan, Yi Jing; Chong, Mei Fong; Law, Chung Lim

2012-12-01

Thermophilic treatment of palm oil mill effluent (POME) was studied in a novel integrated anaerobic-aerobic bioreactor (IAAB). The IAAB was subjected to a program of steady-state operation over a range of organic loading rate (OLR)s, up to 30 g COD/L day in order to evaluate its treatment capacity. The thermophilic IAAB achieved high chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of more than 99% for OLR up to 18.5 g COD/L day. High methane yield of 0.32 LCH(4) (STP)/g COD(removed) with compliance of the final treated effluent to the discharge limit were achieved. This is higher than that of the mesophilic system due to the higher maximum specific growth rate (μ(max)) of the thermophilic microorganisms. Besides, coupling the model of Grau second order model (anaerobic system) with the model of Monod (aerobic system) will completely define the IAAB system. Copyright © 2012 Elsevier Ltd. All rights reserved.

Improved Nitrogen Removal Effect In Continuous Flow A2/O Process Using Typical Extra Carbon Source

NASA Astrophysics Data System (ADS)

Wu, Haiyan; Gao, Junyan; Yang, Dianhai; Zhou, Qi; Cai, Bijing

2010-11-01

In order to provide a basis for optimal selection of carbon source, three typical external carbon sources (i.e. methanol, sodium acetate and leachate) were applied to examine nitrogen removal efficiency of continuous flow A2/O system with the influent from the effluent of grit chamber in the second Kunming wastewater treatment plant. The best dosage was determined, and the specific nitrogen removal rate and carbon consumption rate were calculated with regard to individual external carbon source in A2/O system. Economy and technology analysis was also conducted to select the suitable carbon source with a low operation cost. Experimental results showed that the external typical carbon source caused a remarkable enhancement of system nitrate degradation ability. In comparison with the blank test, the average TN and NH3-N removal efficiency of system with different dosing quantities of external carbon source was improved by 15.2% and 34.2%, respectively. The optimal dosage of methanol, sodium acetate and leachate was respectively up to 30 mg/L, 40 mg/L and 100 mg COD/L in terms of a high nitrogen degradation effect. The highest removal efficiency of COD, TN and NH3-N reached respectively 92.3%, 73.9% and 100% with methanol with a dosage of 30 mg/L. The kinetic analysis and calculation revealed that the greatest denitrification rate was 0.0107 mg TN/mg MLVSSṡd with sodium acetate of 60 mg/L. As to carbon consumption rate, however, the highest value occurred in the blank test with a rate of 0.1955 mg COD/mg MLVSSṡd. Also, further economic analysis proved leachate to be pragmatic external carbon source whose cost was far cheaper than methanol.

Comparison of constructed wetland and stabilization pond for the treatment of digested effluent of swine wastewater.

PubMed

Liu, Gang-Jin; Zheng, Dan; Deng, Liang-Wei; Wen, Quan; Liu, Yi

2014-01-01

A laboratory-scale horizontal subsurface flow constructed wetland (HSFCW) and a stabilization pond (SP) were constructed to compare their performances on the treatment of digested effluent of swine wastewater. After 457 days of operation, the removal efficiencies of the HSFCW were as follows: chemical oxygen demand (COD), 17-54%; total phosphorus (TP), 32-45% and ammonia nitrogen [Formula: see text], 27-88%, while they were 25-55%, 31-56% and 56-98%, respectively, for the SP, with a hydraulic retention time of 54 days and hydraulic loading of 0.01 m³ m⁻² d⁻¹. The average removed loads for the HSFCW were as follows: COD, 0.25-4.33; TP, 0.01-0.11 and [Formula: see text], 0.34-2.54 g m⁻² d⁻¹, while they were 0.25-4.45, 0.02-0.13 and 0.72-2.87 g m⁻² d⁻¹, respectively, for the SP. The SP performed better than the HSFCW because the SP showed a 20% of higher removal efficiency for [Formula: see text] than the HSFCW. Especially, the COD removal rate of SP was 10% higher than the HSFCW when the influent concentration was at the lowest and highest stages. Meanwhile, given the lower costs, the SP is more suitable for the treatment of digested effluent of swine wastewater than the HSFCW.

Treatment of winery wastewater in a conventional municipal activated sludge process: five years of experience.

PubMed

Bolzonella, D; Zanette, M; Battistoni, P; Cecchi, F

2007-01-01

A full-scale wastewater treatment plant where municipal and winery wastewaters were co-treated was studied for five years. The experimental results showed that suspended solids, COD, nitrogen and phosphorous were effectively removed both during the treatment of municipal wastewater and the cotreatment of municipal and winery wastewater. The sludge production increase from 4 tons to 5.5 tons per day during the harvesting and wine making period. In any case the specific sludge production was 0.2 kgMLVSS per kgCOD(removed) despite the organic loading increasing. About 70% of the COD was removed through respiration. Also the energy demand increased from 6,000 to 7,000 kWh per day. The estimated costs for the treatment of the winery wastewater was 0.2-0.3 Euros per m3 of treated wastewater. With reference to the process efficiency, the nitrogen removal was just 20%. The co-treatment of municipal and winery wastewater in conventional activated sludge processes can be a feasible solution for the treatment of these streams at relatively low costs.

Investigation and optimization of the novel UASB-MFC integrated system for sulfate removal and bioelectricity generation using the response surface methodology (RSM).

PubMed

Zhang, Baogang; Zhang, Jing; Yang, Qi; Feng, Chuanping; Zhu, Yuling; Ye, Zhengfang; Ni, Jinren

2012-11-01

COD/sulfate ratio and hydraulic residence time (HRT), both of which influence sulfate loadings jointly, are recognized as the most two important affecting factors for sulfate removal and bioelectricity generation in the novel up-flow anaerobic sludge blanket reactor-microbial fuel cell (UASB-MFC) integrated system. The response surface methodology (RSM) was employed for the optimization of this system and the optimum condition with COD/sulfate ratio of 2.3 and HRT of 54.3h was obtained with the target of maximizing the power output. In terms of maximizing the total sulfate removal efficiency, the obtained optimum condition was COD/sulfate ratio of 3.7 and HRT of 55.6h. Experimental results indicated the undistorted simulation and reliable optimized results. These demonstrated that RSM was effective to evaluate and optimize the UASB-MFC system for sulfate removal and energy recovery, providing a promising guide to further improvement of the system for potential applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

Rotating belt sieves for primary treatment, chemically enhanced primary treatment and secondary solids separation.

PubMed

Rusten, B; Rathnaweera, S S; Rismyhr, E; Sahu, A K; Ntiako, J

2017-06-01

Fine mesh rotating belt sieves (RBS) offer a very compact solution for removal of particles from wastewater. This paper shows examples from pilot-scale testing of primary treatment, chemically enhanced primary treatment (CEPT) and secondary solids separation of biofilm solids from moving bed biofilm reactors (MBBRs). Primary treatment using a 350 microns belt showed more than 40% removal of total suspended solids (TSS) and 30% removal of chemical oxygen demand (COD) at sieve rates as high as 160 m³/m²-h. Maximum sieve rate tested was 288 m³/m²-h and maximum particle load was 80 kg TSS/m²-h. When the filter mat on the belt increased from 10 to 55 g TSS/m², the removal efficiency for TSS increased from about 35 to 60%. CEPT is a simple and effective way of increasing the removal efficiency of RBS. Adding about 1 mg/L of cationic polymer and about 2 min of flocculation time, the removal of TSS typically increased from 40-50% without polymer to 60-70% with polymer. Using coagulation and flocculation ahead of the RBS, separation of biofilm solids was successful. Removal efficiencies of 90% TSS, 83% total P and 84% total COD were achieved with a 90 microns belt at a sieve rate of 41 m³/m²-h.

Treatment of laundrette wastewater using Starbon and Fenton's reagent.

PubMed

Tony, Maha A; Parker, Helen L; Clark, James H

2016-09-18

The use of grey water for a variety of purposes is gaining increased popularity as a means of preserving scarce freshwater resources. In this work, catalytic oxidation over Fenton's reagent and adsorption techniques using Starbon (mesoporous material derived from polysaccharides) has been applied. These novel techniques are used as an alternative to already studied treatments of grey water such as filtration and/or biological processes. In this study, grey water, collected from a commercial laundrette, has been used. Treatment efficiency was determined by changes in the chemical oxygen demand (COD) of the grey water. Experiments using Fenton's reagent at optimum conditions of Fe(3+) = 40 mg L(-1); H2O2 = 400 mg L(-1) and pH 3 were very successful, resulting in a 95% COD removal after 15 min. Treatment with Starbon adsorption was also effective, reaching up to 81% COD removal at pH 3 within 1 h. The combined treatment with Fenton's reagent and Starbon resulted in a 93% COD removal at a significantly reduced concentration of Fenton's reagent compared to the treatment with solo Fenton's reagent. This lower chemical dose has the advantage of reducing costs and lowering sludge generation.

Treatment of sanitary landfill leachates in a lab-scale gradual concentric chamber (GCC) reactor.

PubMed

Mendoza, Lourdes; Verstraete, Willy; Carballa, Marta

2010-03-01

Sanitary landfill leachates are a major environmental problem in South American countries where sanitary landfills are still constructed and appropriate designs for the treatment of these leachates remain problematic. The performance of a lab-scale Gradual Concentric Chamber (GCC) reactor for leachates treatment is presented in this study. Two types of sanitary landfill residuals were evaluated, one directly collected from the garbage trucks (JGL), with high organic strength (84 g COD/l) and the second one, a 6-month-generated leachate (YL) collected from the lagoon of the sanitary landfill in Quito, Ecuador, with an organic strength of 66 g COD/l. Different operational parameters, such as organic loading rate (OLR), temperature, recycling and aeration, were tested. The GCC reactor was found to be a robust technology to treat these high-strength streams with organic matter removal efficiencies higher than 65%. The best performance of the reactors (COD removal efficiencies of 75-80%) was obtained at a Hydraulic Retention Time (HRT) of around 20 h and at 35 degrees C, with an applied OLR up to 70 and 100 g COD/l per day. Overall, the GCC reactor concept appears worth to be further developed for the treatment of leachates in low-income countries.

Treatment and utilization of septic tank effluent using vertical-flow constructed wetlands and vegetable hydroponics.

PubMed

Cui, Li-Hua; Luo, Shi-Ming; Zhu, Xi-Zhen; Liu, Ying-Hu

2003-01-01

Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effluent was treated by vertical flow filter. So the concentration of COD and BOD5 in the treated effluent could meet the quality standard for irrigation water. After that the treated effluent was used for hydroponic cultivation of water spinach and romaine lettuce, the removal efficiencies of the whole system for COD, BOD5, SS, TN and TP were 71.4%, 97.5%, 96.9%, 86.3%, and 87.4%, respectively. And it could meet the integrated wastewater discharge standard for secondary biological treatment plant. It was found that using treated effluent for hydroponic cultivation of vegetables could reduce the nitrate content in vegetables. The removal rates for total bacteria and coliform index by using vertical flow bed system with cinder substrate were 80%-90% and 85%-96%, respectively.

Effect of carbon source on nitrogen removal in anaerobic ammonium oxidation (anammox) process.

PubMed

Zhu, Weiqiang; Zhang, Peiyu; Dong, Huiyu; Li, Jin

2017-04-01

Anaerobic ammonium oxidation (anammox) has been regarded as an efficient process to treat high-strength wastewater without organic carbon source. To investigate nitrogen removal performance of anammox in presence of organic carbon source can broaden its application on organic wastewater treatment. In this work, effect of carbon source on anammox process was explored. Operating temperature was set at 35 ± 1°C. Influent pH and hydraulic retention time were 7.5 and 6 h, respectively. Effluent [Formula: see text] was affected little with COD no more than 480 mg/L. Independent of carbon source content, nitrite removal rate was around 99%. The variation of [Formula: see text] lagged behind [Formula: see text] at high COD content, and pH could be used as an indicator for [Formula: see text] removal. Specific anammox activity dropped from 0.39 to 0.19  [Formula: see text] at COD=720 mg/L. The remodified logistic model was quite appropriate for describing the nitrogen removal kinetics and predicting the performance of anammox process in presence of carbon source. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Organic and nitrogen removal from landfill leachate in aerobic granular sludge sequencing batch reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei Yanjie; Key Laboratory of Environmental Protection in Water Transport Engineering Ministry of Communications, Tianjin Research Institute of Water Transport Engineering, Tianjin 300456; Ji Min, E-mail: jmtju@yahoo.cn

2012-03-15

Highlights: Black-Right-Pointing-Pointer Aerobic granular sludge SBR was used to treat real landfill leachate. Black-Right-Pointing-Pointer COD removal was analyzed kinetically using a modified model. Black-Right-Pointing-Pointer Characteristics of nitrogen removal at different ammonium inputs were explored. Black-Right-Pointing-Pointer DO variations were consistent with the GSBR performances at low ammonium inputs. - Abstract: Granule sequencing batch reactors (GSBR) were established for landfill leachate treatment, and the COD removal was analyzed kinetically using a modified model. Results showed that COD removal rate decreased as influent ammonium concentration increasing. Characteristics of nitrogen removal at different influent ammonium levels were also studied. When the ammonium concentration inmore » the landfill leachate was 366 mg L{sup -1}, the dominant nitrogen removal process in the GSBR was simultaneous nitrification and denitrification (SND). Under the ammonium concentration of 788 mg L{sup -1}, nitrite accumulation occurred and the accumulated nitrite was reduced to nitrogen gas by the shortcut denitrification process. When the influent ammonium increased to a higher level of 1105 mg L{sup -1}, accumulation of nitrite and nitrate lasted in the whole cycle, and the removal efficiencies of total nitrogen and ammonium decreased to only 35.0% and 39.3%, respectively. Results also showed that DO was a useful process controlling parameter for the organics and nitrogen removal at low ammonium input.« less

Effect of organic matter to nitrogen ratio on membrane bioreactor performance.

PubMed

Hao, L; Liao, B Q

2015-01-01

Effect of chemical oxygen demand (COD) to nitrogen (COD:N) ratio in feed on the performance of aerobic membrane bioreactor (MBR) for treating a synthetic high-strength industrial waste water containing glucose was studied for over 370 days. The widely recommended nutrients ratio (COD:N:P = 100:5:1) is not necessary for aerobic biological industrial waste water treatment. An increased COD:N ratio from 100:5 to 100:2.5 and 100:1.8 had a limited impact on COD removal efficiency and further led to a significant improvement in membrane performance, a reduced sludge yield, and improved effluent quality in terms of residual nutrients. An increased COD:N ratio will benefit the industrial waste water treatment using MBRs by reducing membrane fouling and sludge yield, saving chemical costs, and reducing secondary pollution by nutrients addition. Optimization of nutrients usage should be conducted for specific industrial waste water streams.

Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)

NASA Astrophysics Data System (ADS)

Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

2010-11-01

This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

Microalgal cultivation in wastewater from the fermentation effluent in Riboflavin (B2) manufacturing for biodiesel production.

PubMed

Sun, Xuefei; Wang, Cunwen; Li, Zihao; Wang, Weiguo; Tong, Yanjie; Wei, Jiang

2013-09-01

In this work, the acclimation of Chlorella pyrenoidosa in diluted wastewater was studied to produce biomass and remove chemical oxygen demand (COD), ammonia-N and phosphorous. The results indicated that the optimal conditions (the volume ratio of wastewater, light intensity, culture temperature, CO2 concentration in feeding gas) which could influence the wastewater treatment efficiency were 0.05, 250 photons m(-2) s(-1), 28 °C and 5%, respectively. Under these conditions, the removal efficiency of COD reached up to 89.2%, while the total nitrogen and total phosphorous decreased by 64.52% and 82.20%, respectively. With the second treatment, COD in the wastewater was further reduced to less than 100 mg/L while it was only reduced to 542.9 mg/L after the first treatment. The treated wastewater could be discharged directly or subjected to for further treatment for recycling. In addition, 1.25 g/L of the biomass and 38.27% (dry basis, w%) of lipid content were reached after microalgal cultivation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optimization of stabilized leachate treatment using ozone/persulfate in the advanced oxidation process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abu Amr, Salem S.; Aziz, Hamidi Abdul, E-mail: cehamidi@eng.usm.my; Adlan, Mohd Nordin

Highlights: ► Ozone and persulfate reagent (O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) was used to treat stabilized leachate. ► Central composite design (CCD) with response surface methodology (RSM) was applied. ► Operating variables including ozone and persulfate dosage, pH variance, and reaction time. ► Optimum removal of COD, color, and NH{sub 3}–N was 72%, 96%, and 76%, respectively. ► A good value of ozone consumption (OC) obtained with 0.60 (kg O{sub 3}/kg COD). - Abstract: The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate inmore » an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH{sub 3}–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m{sup 3} ozone, 1 g/1 g COD{sub 0}/S{sub 2}O{sub 8}{sup 2-} ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH{sub 3}–N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O{sub 3}/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S{sub 2}O{sub 8}{sup 2-} only, to evaluate its effectiveness. The combined method (i.e., O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) achieved higher removal efficiencies for COD, color, and NH{sub 3}–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.« less

Effect of static magnetic field on electricity production and wastewater treatment in microbial fuel cells.

PubMed

Tao, Qinqin; Zhou, Shaoqi

2014-12-01

The effect of a magnetic field (MF) on electricity production and wastewater treatment in two-chamber microbial fuel cells (MFCs) has been investigated. Electricity production capacity could be improved by the application of a low-intensity static MF. When a MF of 50 mT was applied to MFCs, the maximum voltage, total phosphorus (TP) removal efficiency, and chemical oxygen demand (COD) removal efficiency increased from 523 ± 2 to 553 ± 2 mV, ∼93 to ∼96 %, and ∼80 to >90 %, respectively, while the start-up time and coulombic efficiency decreased from 16 to 10 days and ∼50 to ∼43 %, respectively. The MF effects were immediate, reversible, and not long lasting, and negative effects on electricity generation and COD removal seemed to occur after the MF was removed. The start-up and voltage output were less affected by the MF direction. Nitrogen compounds in magnetic MFCs were nitrified more thoroughly; furthermore, a higher proportion of electrochemically inactive microorganisms were found in magnetic systems. TP was effectively removed by the co-effects of microbe absorption and chemical precipitation. Chemical precipitates were analyzed by a scanning electron microscope capable of energy-dispersive spectroscopy (SEM-EDS) to be a mixture of phosphate, carbonate, and hydroxyl compounds.

[Wastewater from the condensation and drying section of ABS was pretreated by microelectrolysis].

PubMed

Lai, Bo; Qin, Hong-Ke; Zhou, Yue-Xi; Song, Yu-Dong; Cheng, Jia-Yun; Sun, Li-Dong

2011-04-01

Wastewater from the condensation and drying section of acrylonitrile-butadiene-styrene (ABS) resin plant was pretreated by the microelectrolysis, and the effect of the influent pH value on the pollution removal efficiency of the microelectrolysis was mainly studied. In order to study the electrochemical action of the microelectrolysis for the degradation of toxic refractory organic pollutants, two control experiments of activated carbon and iron were set up. The results showed that the TOC removal efficiencies were all fluctuated between 40% and 60% under the condition of different influent pH values. The microelectrolysis can decompose and transform the toxic refractory organic pollutants and increase the BOD5/COD ratio from 0.32 to 0.60, which increased the biodegradability of ABS resin wastewater significantly. When the pH value of influent was 4.0, the BOD5/COD ratio of effluent reached 0.71. The result of UV-vis spectra indicates that the removal efficiency of the organic nitrile was the highest with influent pH was 4.0. Therefore, the best influent pH value of microelectrolysis was 4.0.

Ozonation of exhausted dark shade reactive dye bath for reuse.

PubMed

Sundrarajan, M; Vishnu, G; Joseph, Kurian

2006-10-01

Exhausted reactive dye bath of dark shades were collected from cotton knit wear dyeing units in Tirupur. Ozonation was conducted in a column reactor system fed with ozone at the rate of 0.16 g/min to assess its efficiency in reducing the color, chemical oxygen demand and total organic carbon. The potential of the decolorized dye bath for its repeated reuse was also analyzed. The results from the reusability studies indicate that the dyeing quality was not affected by the reuse of decolorized dye bath for two successive cycles. Complete decolorization of the effluent was achieved in 60 minutes contact time at an ozone consumption of 183 mg/L for Red, 175 for Navy Blue and 192 for Green shades respectively. The corresponding COD removal was 60%, 54% and 63% for the three shades while TOC removal efficiency was 59%, 55% and 62% respectively. It is concluded that ozonation is efficient in decolorization of exhausted dye bath effluents containing conventional reactive dyes. However, the corresponding removal of COD from the textile effluent was not significant.

Effect of the anode feeding composition on the performance of a continuous-flow methane-producing microbial electrolysis cell.

PubMed

Zeppilli, Marco; Villano, Marianna; Aulenta, Federico; Lampis, Silvia; Vallini, Giovanni; Majone, Mauro

2015-05-01

A methane-producing microbial electrolysis cell (MEC) was continuously fed at the anode with a synthetic solution of soluble organic compounds simulating the composition of the soluble fraction of a municipal wastewater. The MEC performance was assessed at different anode potentials in terms of chemical oxygen demand (COD) removal efficiency, methane production, and energy efficiency. As a main result, about 72-80% of the removed substrate was converted into current at the anode, and about 84-86% of the current was converted into methane at the cathode. Moreover, even though both COD removed and methane production slightly decreased as the applied anode potential decreased, the energy efficiency (i.e., the energy recovered as methane with respect to the energy input into the system) increased from 54 to 63%. Denaturing gradient gel electrophoresis (DGGE) analyses revealed a high diversity in the anodic bacterial community with the presence of both fermentative (Proteiniphilum acetatigenes and Petrimonas sulphurifila) and aerobic (Rhodococcus qingshengii) microorganisms, whereas only two microorganisms (Methanobrevibacter arboriphilus and Methanosarcina mazei), both assignable to methanogens, were observed in the cathodic community.

Fungi immobilization for landfill leachate treatment.

PubMed

Saetang, Jenjira; Babel, Sandhya

2010-01-01

This paper investigated treatment of landfill leachate collected from Nonthaburi landfill site, Thailand, by using immobilized white rot fungi, namely, Trametes versicolor BCC 8725 and Flavodon flavus BCC 17421. Effects of pH and co-substrates were investigated at different contact times. Three types of co-substrates as carbon source used in this study are glucose, corn starch and cassava. Treatment efficiency was evaluated based on color, BOD, and COD removal. Initial BOD and COD were found to be 5,600 and 34,560 mg/L, respectively. The optimum pH was found to be 4, the optimum co-substrate concentration (glucose, corn starch and cassava) was 3 g/L and the optimum contact time was 10 days for both types of fungi. Addition of glucose, corn starch and cassava as co-substrate at optimum conditions could remove 78, 74, and 66% of color, respectively for T. versicolor and 73, 68, and 60%, respectively, for F. flavus. Moreover, for T. versicolor, BOD and COD reduction of 69 and 57%, respectively, could be achieved at optimum conditions when using glucose as a co-substrate. For F. flavus, BOD and COD reduction of 66 and 52%, respectively were obtained when using glucose as a co-substrate. White rot fungi can be considered potentially useful in the treatment of landfill leachate as they can help in removing color, BOD and COD due to their biodegradative abilities.

Anaerobic digestion of olive mill wastewaters in biofilm reactors packed with granular activated carbon and "Manville" silica beads.

PubMed

Bertin, Lorenzo; Berselli, Sara; Fava, Fabio; Petrangeli-Papini, Marco; Marchetti, Leonardo

2004-01-01

Anaerobic digestion is one of the most promising technologies for disposing olive mill wastewaters (OMWs). The process is generally carried out in the conventional contact bioreactors, which however are often unable to efficiently remove OMW phenolic compounds, that therefore occur in the effluents. The possibility of mitigating this problem by employing an anaerobic OMW-digesting microbial consortium passively immobilized in column reactors packed with granular activated carbon (GAC) or "Manville" silica beads (SB) was here investigated. Under batch conditions, both GAC- and SB-packed-bed biofilm reactors exhibited OMW COD and phenolic compound removal efficiencies markedly higher (from 60% to 250%) than those attained in a parallel anaerobic dispersed growth reactor developed with the same inoculum; GAC-reactor exhibited COD and phenolic compound depletion yields higher by 62% and 78%, respectively, than those achieved with the identically configured SB-biofilm reactor. Both biofilm reactors also mediated an extensive OMW remediation under continuous conditions, where GAC-reactor was much more effective than the corresponding SB-one, and showed a tolerance to high and variable organic loads along with a volumetric productivity in terms of COD and phenolic compound removal significantly higher than those averagely displayed by most of the conventional and packed-bed laboratory-scale reactors previously proposed for the OMW digestion.

Aerobic digestion of starch wastewater in a fluidized bed bioreactor with low density biomass support.

PubMed

Rajasimman, M; Karthikeyan, C

2007-05-08

A solid-liquid-gas, multiphase, fluidized bed bioreactor with low density particles was used in this study to treat the high organic content starch industry wastewater. The characteristics of starch wastewater were studied. It shows high organic content and acidic nature. The performance of a three phase fluidized bed bioreactor with low density biomass support was studied under various average initial substrate concentrations, by varying COD values (2250, 4475, 6730 and 8910 mg/L) and for various hydraulic retention times (8, 16, 24, 32 and 40 h) based on COD removal efficiency. The optimum bed height for the maximum COD reduction was found to be 80 cm. Experiments were carried out in the bioreactor at an optimized bed height, after the formation of biofilm on the surface of low-density particles (density=870 kg/m(3)). Mixed culture obtained from the sludge, taken from starch industry effluent treatment plant, was used as the source for microorganisms. From the results it was observed that increase in initial substrate concentration leads to decrease in COD reduction and COD reduction increases with increase in hydraulic retention time. The optimum COD removal of 93.8% occurs at an initial substrate concentration of 2250 mg/L and for the hydraulic retention time of 24h.

Effects of electric potential, NaCl, pH and distance between electrodes on efficiency of electrolysis in landfill leachate treatment.

PubMed

Erabee, Iqbal K; Ahsan, Amimul; Jose, Bipin; Arunkumar, T; Sathyamurthy, R; Idrus, Syazwani; Daud, N N Nik

2017-07-03

This study investigated the effects of different parameters on the removal efficiencies of organic and inorganic pollutants in landfill leachate treatment by electrolysis. Different parameters were considered such as the electric potential (e.g., 24, 40 and 60 V), hydraulic retention time (HRT) (e.g., 40, 60, 80, 100 and 120 min), sodium chloride (NaCl) concentration (e.g., 1, 3, 5 and 7%), pH (e.g., 3, 7 and 9), electrodes materials [e.g., aluminum (Al) and iron (Fe)] and distance between electrodes (e.g., 1, 2 and 3 cm). The best operational condition of electrolysis was then recommended. The electric potential of 60 V with HRT of 120 min at 5% of NaCl solution using Al as anode and Fe as cathode (kept at a distance of 3 cm) was the most efficient condition which increased the removal efficiencies of various parameters such as turbidity, salinity, total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and heavy metals (e.g., Zn and Mn). The higher removal percentages of many parameters, especially COD (94%) and Mn (93%) indicated that the electrolysis is an efficient technique for multi-pollutants (e.g., organic, inorganic and heavy metals) removal from the landfill leachate.

Incorporating biodegradation and advanced oxidation processes in the treatment of spent metalworking fluids.

PubMed

MacAdam, Jitka; Ozgencil, Haci; Autin, Olivier; Pidou, Marc; Temple, Clive; Parsons, Simon; Jefferson, Bruce

2012-12-01

The treatment of spent metalworking fluids (MWFs) is difficult due to their complex and variable composition. Small businesses often struggle to meet increasingly stringent legislation and rising costs as they need to treat this wastewater on site annually over a short period. Larger businesses that treat their wastewater continuously can benefit from the use of biological processes, although new MWFs designed to resist biological activity represent a challenge. A three-stage treatment is generally applied, with the oil phase being removed first, followed by a reduction in COD loading and then polishing of the effluent's quality in the final stage. The performance of advanced oxidation processes (AOPs), which could be of benefit to both types of businesses was studied. After assessing the biodegradability of spent MFW, different AOPs were used (UV/H2O2, photo-Fenton and UV/TiO2) to establish the treatability of this wastewater by hydroxyl radicals (*OH). The interactions of both the chemical and biological treatments were also investigated. The wastewater was found to be readily biodegradable in the Zahn-Wellens test with 69% COD and 74% DOC removal. The UV/TiO2 reactor was found to be the cheapest option achieving a very good COD removal (82% at 20 min retention time and 10 L min(-1) aeration rate). The photo-Fenton process was found to be efficient in terms of degradation rate, achieving 84% COD removal (1 M Fe2+, 40 M H2O2, 20.7 J cm(-2), pH 3) and also improving the wastewater's biodegradability. The UV/H202 process was the most effective in removing recalcitrant COD in the post-biological treatment stage.

Performance of hybrid subsurface constructed wetland system for piggery wastewater treatment.

PubMed

Zhang, X; Inoue, T; Kato, K; Harada, J; Izumoto, H; Wu, D; Sakuragi, H; Ietsugu, H; Sugawara, Y

2016-01-01

The objective of this study was to evaluate performance of a hybrid constructed wetland (CW) built for high organic content piggery wastewater treatment in a cold region. The system consists of four vertical and one horizontal flow subsurface CWs. The wetland was built in 2009 and water quality was monitored from the outset. Average purification efficiency of this system was 95±5, 91±7, 89±8, 70±10, 84±15, 90±6, 99±2, and 93±16% for biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total carbon (TC), total nitrogen (TN), ammonium-N (NH4-N), total phosphorus (TP), total coliform (T. Coliform), and suspended solids (SS), respectively during August 2010-December 2013. Pollutant removal rate was 15±18 g m(-2) d(-1), 49±52 g m(-2) d(-1), 6±4 g m(-2) d(-1), 7±5 g m(-2) d(-1), and 1±1 g m(-2) d(-1) for BOD5, COD, TN, NH4-N, and TP, respectively. The removal efficiency of BOD5, COD, NH4-N, and SS improved yearly since the start of operation. With respect to removal of TN and TP, efficiency improved in the first three years but slightly declined in the fourth year. The system performed well during both warm and cold periods, but was more efficient in the warm period. The nitrate increase may be attributed to a low C/N ratio, due to limited availability of carbon required for denitrification.

Simultaneous removal of carbon and nitrogen by mycelial pellets of a heterotrophic nitrifying fungus-Penicillium sp. L1.

PubMed

Liu, Yuxiang; Hu, Tingting; Zhao, Jing; Lv, Yongkang; Ren, Ruipeng

2017-02-01

A novel heterotrophic nitrifying fungus, defined as Penicillium sp. L1, can form mycelial pellets in liquid medium in this study. The effects of inoculation method, C/N ratio, initial pH, and temperature were gradually evaluated to improve the simultaneous removal of total nitrogen (TN) and chemical oxygen demand (COD) in wastewater by Penicillium sp. L1. Results showed that compared with spore inoculation, 48 h pellet inoculum could significantly increase the pellet size (from about 1.5 mm to 3.2 mm) and improve the removal capability, particularly for COD removal (from less than 50-86.20%). The removal efficiencies of TN and COD reached 98.38% (from 136.01 mg/L to 2.20 mg/L) and 92.40% (from 10,720 mg/L to 815 mg/L) under the following conditions: C/N 36, pH 3, 30°C, and inoculation with 48 h pellets. The pellet diameter reached 4.8 mm after 4-day cultivation. In this case, Penicillium sp. L1 removed TN from 415.93 mg/L to 43.39 mg/L, as well as COD from 29,533 mg/L to 8850 mg/L. Overall, the results indicated that the pellet size was closely related to the pollutant-removal ability of Penicillium sp. L1. Furthermore, mycelial pellets (4.8 mm, dead) only adsorbed 38.08% TN (from 125.45 mg/L to 77.78 mg/L), which indicated that adsorption did not play a major role in the nitrogen-removal process. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Characterization and treatment of Denizli landfill leachate using anaerobic hybrid/aerobic CSTR systems.

PubMed

Ağdağ, Osman Nuri

2011-01-01

Leachate generated in municipal solid waste landfill contains large amounts of organic and inorganic contaminants. In the scope of the study, characterization and anaerobic/aerobic treatability of leachate from Denizli (Turkey) Sanitary Landfill were investigated. Time-based fluctuations in characteristics of leachate were monitored during a one-year period. In characterization study; chemical oxygen demand (COD), biochemical oxygen demand (BOD) dissolved oxygen, temperature, pH, alkalinity, volatile fatty acids, total nitrogen, NH4-N, BOD5/COD ratio, suspended solid, inert COD, anaerobic toxicity assay and heavy metals concentrations in leachate were monitored. Average COD, BOD and NH4-N concentration in leachate were measured as 18034 mg/l, 11504 mg/l and 454 mg/l, respectively. Generally, pollution parameters in leachate were higher in summer and relatively lower in winter due to dilution by precipitation. For treatment of leachate, two different reactors, namely anaerobic hybrid and aerobic completely stirred tank reactor (CSTR) having effective volumes of 17.7 and 10.5 litres, respectively, were used. After 41 days of start-up period, leachate was loaded to hybrid reactor at 10 different organic loading rates (OLRs). OLR was increased by increasing COD concentrations. COD removal efficiency of hybrid reactor was carried out at a maximum of 91%. A percentage of 96% of residual COD was removed in the aerobic reactor. NH4-N removal rate in CSTR was quite high. In addition, high methane content was obtained as 64% in the hybrid reactor. At the end of the study, after 170 operation days, it can be said that the hybrid reactor and CSTR were very effective for leachate treatment.

The impact of microbial ecology and chemical profile on the enhanced biological phosphorus removal (EBPR) process: a case study of Northern Wastewater Treatment Works, Johannesburg.

PubMed

Kamika, Ilunga; Coetzee, Martie; Mamba, Bhekie Brilliance; Msagati, Titus; Momba, Maggy N B

2014-03-10

The impact of polyphosphate-accumulating organism (PAO) and glycogen-accumulating organism (GAO) populations as well as of the chemical profile on the performance of Unit-3 (open elutriation tanks) and Unit-5 (covered elutriation tank) of the City of Johannesburg Northern Wastewater Treatment Works was determined. Physicochemical parameters of wastewater samples were measured using standard methods. Bacterial diversity was determined using 16S rRNA gene amplicon pyrosequencing of the variable region V1-3. Results showed soluble COD concentrations from settled sewage for Unit-3 at 192.8 mg COD/L and for Unit-5 at 214.6 mg COD/L, which increased to 301.8 mg COD/L and 411.6 mg COD/L in the overflow from elutriation tanks and decreased to 170.9 mg COD/L and 256.3 mg COD/L at the division boxes, respectively. Both long-chain volatile fatty acids (heptanoic acid, isobutyric acid, 3-methylbutanoic acid, pentanoic acid, 4-methylpentanoic acid, methylheptanoic acid) and short-chain volatile fatty acids (acetic acid, propionic acid, isobutyric acid) were present within concentration ranges of 17.19 mg/L to 54.98 mg/L and 13.64 mg/L to 87.6 mg/L for Unit 3 and 38.61 mg/L to58.85 mg/L and 21.63 mg/L to 92.39 mg/L for Unit 5, respectively. In the secondary settling tanks, the phosphate-removal efficiency in Unit-5 appeared to be slightly higher (0.08 mg P/L) compared to that of Unit-3 (0.11 mg P/L). The average DO concentrations (2.1 mg/L and 2.2 mg/L) as well as the pH values (pH 7 to pH 7.5) were found to be slightly higher in Unit-5 in the aerobic zones. The high presence of PAOs in the bioreactors (Unit-5: Dechloromonas (14.96%), Acinetobacter (6.3%), Zoogloea (4.72%) in the anaerobic zone and Dechloromonas (22.37 %) in the aerobic zone; Unit-3: Dechloromonas (37.25%) in the anaerobic zone and Dechloromonas (23.97%) in the aerobic zone) confirmed the phosphate-removal efficiencies of both units. Negligible GAOs were found in the aerobic zones (Defluviicoccus spp.: 0.33% for Unit-5 and 0.68% for Unit-3) and in the anaerobic zones (Defluviicoccus: 9.8% for Unit-3). The high microbial diversity and a negligible percentage of GAOs in Unit-5 could contribute to its high phosphate-removal efficiency, although results did not indicate statistically significant differences between the unit with a covered elutriation tank (Unit-5) and that with open elutriation tanks (Unit-3).

The Impact of Microbial Ecology and Chemical Profile on the Enhanced Biological Phosphorus Removal (EBPR) Process: A Case Study of Northern Wastewater Treatment Works, Johannesburg

PubMed Central

Kamika, Ilunga; Coetzee, Martie; Mamba, Bhekie Brilliance; Msagati, Titus; Momba, Maggy N. B.

2014-01-01

The impact of polyphosphate-accumulating organism (PAO) and glycogen-accumulating organism (GAO) populations as well as of the chemical profile on the performance of Unit-3 (open elutriation tanks) and Unit-5 (covered elutriation tank) of the City of Johannesburg Northern Wastewater Treatment Works was determined. Physicochemical parameters of wastewater samples were measured using standard methods. Bacterial diversity was determined using 16S rRNA gene amplicon pyrosequencing of the variable region V1-3. Results showed soluble COD concentrations from settled sewage for Unit-3 at 192.8 mg COD/L and for Unit-5 at 214.6 mg COD/L, which increased to 301.8 mg COD/L and 411.6 mg COD/L in the overflow from elutriation tanks and decreased to 170.9 mg COD/L and 256.3 mg COD/L at the division boxes, respectively. Both long-chain volatile fatty acids (heptanoic acid, isobutyric acid, 3-methylbutanoic acid, pentanoic acid, 4-methylpentanoic acid, methylheptanoic acid) and short-chain volatile fatty acids (acetic acid, propionic acid, isobutyric acid) were present within concentration ranges of 17.19 mg/L to 54.98 mg/L and 13.64 mg/L to 87.6 mg/L for Unit 3 and 38.61 mg/L to58.85 mg/L and 21.63 mg/L to 92.39 mg/L for Unit 5, respectively. In the secondary settling tanks, the phosphate-removal efficiency in Unit-5 appeared to be slightly higher (0.08 mg P/L) compared to that of Unit-3 (0.11 mg P/L). The average DO concentrations (2.1 mg/L and 2.2 mg/L) as well as the pH values (pH 7 to pH 7.5) were found to be slightly higher in Unit-5 in the aerobic zones. The high presence of PAOs in the bioreactors (Unit-5: Dechloromonas (14.96%), Acinetobacter (6.3%), Zoogloea (4.72%) in the anaerobic zone and Dechloromonas (22.37 %) in the aerobic zone; Unit-3: Dechloromonas (37.25%) in the anaerobic zone and Dechloromonas (23.97%) in the aerobic zone) confirmed the phosphate-removal efficiencies of both units. Negligible GAOs were found in the aerobic zones (Defluviicoccus spp.: 0.33% for Unit-5 and 0.68% for Unit-3) and in the anaerobic zones (Defluviicoccus: 9.8% for Unit-3). The high microbial diversity and a negligible percentage of GAOs in Unit-5 could contribute to its high phosphate-removal efficiency, although results did not indicate statistically significant differences between the unit with a covered elutriation tank (Unit-5) and that with open elutriation tanks (Unit-3). PMID:24619121

Lipid production from tapioca wastewater by culture of Scenedesmus sp. with simultaneous BOD, COD and nitrogen removal

NASA Astrophysics Data System (ADS)

Romaidi; Hasanudin, Muhammad; Kholifah, Khusnul; Maulidiyah, Alik; Putro, Sapto P.; Kikuchi, Akira; Sakaguchi, Toshifumi

2018-05-01

The use of microalgae to produce biodiesel or possibly remove nutrients from industrial wastewater has gained important attention during recent years due to their photosynthetic rate and its versatile nature to grow in various wastewater systems. In this study, a microalgae, Scenedesmus sp., was cultured to enhance the lipid production and nutrients removal from tapioca wastewater sample. To assess lipid production, Scenedesmus sp. was cultured in different concentration of tapioca wastewater sample (from 0 to 100 %), and nutrient removal including BOD, COD, NH4, NO2, NO3 level by Scenedesmus sp. was assessed in 100% of tapioca wastewater culture. After 8 days of culture, it was found out that 50% of tapioca wastewater sample resulted in highest concentration of lipid content than that of the other concentrations. The level of environment indicator as nutrient removal such as BOD, COD, NH4, NO2, NO3 were also decreased up to 74%, 72%, 95%, 91%, and 91%, respectively. The pH condition changed from initial condition acidic (pH: 4) to neutral or basic condition (pH: 7-8) as recommended in wastewater treatment system. This research provided a novel approach and achieved efficient simultaneous lipid production and nutrients removal from tapioca wastewater sample by Scenedesmus’s culture system.

Nutrients removal in hybrid fluidised bed bioreactors operated with aeration cycles.

PubMed

Martin, Martin; Enríquez, L López; Fernández-Polanco, M; Villaverde, S; Garcia-Encina, P A

2007-01-01

Abstract Two hybrid fluidised bed reactors filled with sepiolite and granular activated carbon (GAC) were operated with short cycled aeration for removing organic matter, total nitrogen and phosphorous, respectively. Both reactors were continuously operated with synthetic and/or industrial wastewater containing 350-500 mg COD/L, 110-130 mg NKT/L, 90-100 mg NH3-N/L and 12-15 mg P/L for 8 months. The reactor filled with sepiolite, treating only synthetic wastewater, removed COD, ammonia, total nitrogen and phosphorous up to 88, 91, 55 and 80% with a hydraulic retention time (HRT) of 10 h, respectively. These efficiencies correspond to removal rates of 0.95 kgCODm(-3)d(-1) and 0.16 kg total N m(-3)d(-1). The reactor filled with GAC was operated for 4 months with synthetic wastewater and 4 months with industrial wastewater, removing 98% of COD, 96% of ammonia, and 66% of total nitrogen, with an HRT of 13.6 h. No significant phosphorous removing activity was observed in this reactor. Microbial communities growing with both reactors were followed using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) techniques. The microbial fingerprints, i.e. DGGE profiles, indicated that biological communities in both reactors were stable along the operational period even when the operating conditions were changed.

Decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process.

PubMed

Mohd Nasir, Norlirubayah; Teo Ming, Ting; Ahmadun, Fakhru'l-Razi; Sobri, Shafreeza

2010-01-01

The research conducted a study on decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process. The purposes of this research are to remove pollutant through decomposition and to enhance the biodegradability of textile wastewater. The wastewater is treated using electron beam irradiation as a pre-treatment before undergo an activated sludge process. As a result, for non-irradiated wastewater, the COD removal was achieved to be between 70% and 79% after activated sludge process. The improvement of COD removal efficiency increased to 94% after irradiation of treated effluent at the dose of 50 kGy. Meanwhile, the BOD(5) removal efficiencies of non-irradiated and irradiated textile wastewater were reported to be between 80 and 87%, and 82 and 99.2%, respectively. The maximum BOD(5) removal efficiency was achieved at day 1 (HRT 5 days) of the process of an irradiated textile wastewater which is 99.2%. The biodegradability ratio of non-irradiated wastewater was reported to be between 0.34 and 0.61, while the value of biodegradability ratio of an irradiated wastewater increased to be between 0.87 and 0.96. The biodegradability enhancement of textile wastewater is increased with increasing the doses. Therefore, an electron beam radiation holds a greatest application of removing pollutants and also on enhancing the biodegradability of textile wastewater.

Investigation of Oxidation Methods for Waste Soy Sauce Treatment.

PubMed

Jang, Hyun-Hee; Seo, Gyu-Tae; Jeong, Dae-Woon

2017-10-07

To obtain a suitable oxidation method for removing the color and lowering the chemical oxygen demand (COD) of waste soy sauce, Fenton (Fe 2+ ), Fenton-like (Fe 3+ ), and ozone (O₃) oxidation methods are used as the target reactions. In experimental conditions for Fenton oxidation, the dose of Fe 2+ and Fe 3+ was varied between 100 mg/L and 300 mg/L. The dose of hydrogen peroxide for the reaction was injected from 100-1000 mg/L. For ozone oxidation, the pH was increased from 3 to 14 and the O₃-containing gas was supplied continuously for 30 min through a gas diffuser at the bottom of the reactor at different applied O₃ doses (10-90 mg/L). We subjected it to a simple 1:20 dilution with deionized water to identify the comparison result in detail. O 3 oxidation shows the highest efficiencies of color removal (81.1%) and COD lowering (64.9%) among the three oxidation methods. This is mainly due to the fact that it has a relatively large amount of hydroxyl radical, resulting in the degradation of organics. Thus, O₃ oxidation could be a promising method for removing the color and lowering the COD of waste soy sauce. The critical parameters (pH and applied O₃ dose) were varied systematically to optimize O₃ oxidation. It was found that the optimum pH and applied O₃ dose are 11.0 mg/L and 50.0 mg/L, respectively (color removal = 34.2%, COD removal = 27.4%).

Research on dispose of wastewater from printing and dyeing by CWF combined with Iron-carbon Microelectrolysis

NASA Astrophysics Data System (ADS)

Chen, Xin; Ye, Tingjin; Xu, Zizhen; Chen, Xiaogang; Shi, Liang; He, Lingfeng; Zhang, Yongli

2018-03-01

The carboxymethylchitosan cladding coal ash (CWF) was oxidized by the high temperature using coal ash and sodium carboxymethyl chitosan as raw and processed material for treatment of simulated and actual printing and dyeing wastewater over iron-carbon micro-electrolysis. The results on pH and CWF dosage for effluent dispose were evaluated by the decolorization rate, COD removal efficiency and turbidity removal rate. The experimental results indicated that the decolorization rate was first augmented and then declined with the increase of pH, and attained a peak value when pH was at 5-6. The COD removal efficiency augmented with the augmented of pH, and attained a peak value when pH was 6-7. The turbidity removal rate was first increases and afterwards decreases with the augment of pH, and attained a peak value when pH was at 5-6. Furthermore, the optimum pH for the treatment of simulated dyeing wastewater was 6 over iron-carbon micro-electrolysis, which indicated that the appropriate pH can promote the degradation of wastewater.

Features of Golenkinia sp. and microbial fuel cells used for the treatment of anaerobically digested effluent from kitchen waste at different dilutions.

PubMed

Hou, Qingjie; Cheng, Juan; Nie, Changliang; Pei, Haiyan; Jiang, Liqun; Zhang, Lijie; Yang, Zhigang

2017-09-01

The aim of this work was to study Golenkinia sp. and microbial fuel cells (MFCs) for the treatment of anaerobically digested effluent from kitchen waste (ADE-KW) with different dilution factors. A dual-chamber MFC was fabricated for treating ADE-KW in the two chambers of the MFC and harvesting Golenkinia sp. All the anodic TN was removed more than 80%. COD removal efficiency increased from 48.2% to 76% when the dilution factor increased from 1 to 4. Maximum COD and TN removal rates were 3.56 and 3.71mg·L -1 ·h -1 when ADE-KW was treated without dilution in the anodic chamber. All the cathodic TN and TP removal efficiencies were approximately 90%. The highest open circuit voltage (OCV) and power density were approximately 400mV and 400mW when ADE-KW was treated directly (undiluted) in the MFC, with the highest biomass and total lipid content production of Golenkinia sp. in the cathodic chamber. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biological denitrification from mature landfill leachate using a food-waste-derived carbon source.

PubMed

Yan, Feng; Jiang, Jianguo; Zhang, Haowei; Liu, Nuo; Zou, Quan

2018-05-15

The mature landfill leachate containing high ammonia concentration (>1000 mg/L) is a serious threat to environment; however, the low COD to TN ratio (C/N, <3) strongly inhibits the denitrification process and poses a severe obstacle for efficient treatment. Herein, two kinds of acidogenic liquids, fermented from oil-removed food waste and oil-added food waste, were first applied as external carbon sources for the biological nitrogen removal from mature landfill leachate in an aerobic/anoxic membrane bioreactor. "Acidogenic liquid b" served quite better than commercial sodium acetate, considering the higher denitrification efficiency and the slightly rapider denitrification rate. The effect of C/N and temperature were investigated under hydraulic retention time (HRT) of 7 d, which showed that C/N ≥ 7 (25 °C) was enough to meet the general discharge standards of NH 4 + -N, TN and COD in China. Even for some special areas of China, the more stringent discharge standards (NH 4 + -N ≤ 8 mg/L, TN ≤ 20 mg/L) could also be achieved under longer HRT of 14 d and C/N ≥ 6. Notably, the COD concentration in effluent could also be well reduced to 50-55 mg/L, without further physical-chemical treatment. This proposed strategy, involving the high-value utilization of food waste, is thus promising for efficient nitrogen removal from mature landfill leachate. Copyright © 2018 Elsevier Ltd. All rights reserved.

Survey of dissolved air flotation system efficiency for reduce of pollution of vegetable oil industry wastewater.

PubMed

Keramati, H; Alidadi, H; Parvaresh, A R; Movahedian, H; Mahvi, A H

2008-10-01

The aim of this research was to sudy the reduction of pollution of vegetable oil manufacturing wastewater with DAF system. At first phase of this examination, the optimum dosage of the coagulants was determined. The coagulants that used in this study were Alum and Ferric Chloride. The second phase was flotation in this series of examinations, oil, COD, total solid, volatile solid, fixed solid and suspended solid measured in raw wastewater and the effluent of the DAF pilot. Optimum value of pH for alum and ferric chloride obtained 7.5 and 5.5, respectively. Optimum dosage for these obtained 30 and 32 mg L(-1) in this research. Mean removal for the parameters ofoil, COD, total solid, volatile solid, fixed solid and suspended solid obtained 75.85, 78.27, 77.32, 82.47, 73.52 and 85.53%, respectively. With pressure rising from 3 to 4 and 5 atm removing rate of COD, total solid, volatile solid, fixed solid parameters reduced, but oil and suspended solid have increase. In addition, following increase of flotation time up to 120 sec all of the measured parameters have increase in removing rate. Optimum A/S for removal of COD, total solid, volatile solid, fixed solid parameters obtained 0.001 and for oil and suspended solid obtained 0.0015.

Different treatment strategies for highly polluted landfill leachate in developing countries.

PubMed

Mahmud, Kashif; Hossain, Md Delwar; Shams, Shahriar

2012-11-01

The aim of this research was to determine appropriate treatment technique for effective treatment of heavily polluted landfill leachate. We accomplished several treatment experiments: (i) aerobic biological treatment, (ii) chemical coagulation, (iii) advanced oxidation process (AOP) and (iv) several combined treatment strategies. Efficiency of these treatment procedures were monitored by analysing COD and colour removal. Leachate used for this study was taken from Matuail landfill site at Dhaka city. With extended aeration process which is currently used in Matuail landfill site for leachate treatment, maximum COD and colour removal of 36% and 20%, respectively could be achieved with optimum retention period of 7 days. With optimum aluminium sulphate dose of 15,000 mg/L and pH value of 7.0, maximum COD and colour removals of 34% and 66%, respectively were observed by using chemical coagulation. With optimum pH of 5.0 and optimum dosages of reagents having H(2)O(2)/Fe(2+) molar ratio of 1.3 the highest removal of COD and colour were found 68% and 87%, respectively with sludge production of 55%. Fenton treatment which is an advanced oxidation process was the most successful between these three separate treatment procedures. Among the combined treatment options performed, extended aeration followed by Fenton method was the most suitable one. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electrochemical treatment of cetrimonium chloride with boron-doped diamond anodes. A technical and economical approach.

PubMed

de Araújo, Brenda R S; Linares León, José J

2018-05-15

This study presents the results of the electrochemical degradation of the emulsifier cetrimonium chloride (CTAC) on a boron-doped diamond (BDD) anode under different current densities and flow rates. Higher values of these parameters result in a more rapid removal. Nevertheless, operation at low current reduces the required applied charge and increases the chemical oxygen demand (COD) removal efficiency, as there is less development of ineffective parasitic reactions. On the other hand, high flow rates reduce the required volumetric applied charge and increase the COD removal current efficiency. In order to assist and enrich the study, an economic analysis has been performed. For short expected plant lifespans, operation at low current is advantageous due to the lower investment required, whereas for longer expected lifespans, the operational costs make the lower current densities less costly. High flow rates are always advantageous from a financial point of view. Copyright © 2018 Elsevier Ltd. All rights reserved.

Treatment of winery wastewater by electrochemical methods and advanced oxidation processes.

PubMed

Orescanin, Visnja; Kollar, Robert; Nad, Karlo; Mikelic, Ivanka Lovrencic; Gustek, Stefica Findri

2013-01-01

The aim of this research was development of new system for the treatment of highly polluted wastewater (COD = 10240 mg/L; SS = 2860 mg/L) originating from vine-making industry. The system consisted of the main treatment that included electrochemical methods (electro oxidation, electrocoagulation using stainless steel, iron and aluminum electrode sets) with simultaneous sonication and recirculation in strong electromagnetic field. Ozonation combined with UV irradiation in the presence of added hydrogen peroxide was applied for the post-treatment of the effluent. Following the combined treatment, the final removal efficiencies of the parameters color, turbidity, suspended solids and phosphates were over 99%, Fe, Cu and ammonia approximately 98%, while the removal of COD and sulfates was 77% and 62%, respectively. A new approach combining electrochemical methods with ultrasound in the strong electromagnetic field resulted in significantly better removal efficiencies for majority of the measured parameters compared to the biological methods, advanced oxidation processes or electrocoagulation. Reduction of the treatment time represents another advantage of this new approach.

Effects of ultrasonic and hydrodynamic cavitation on the treatment of cork wastewater by flocculation and Fenton processes.

PubMed

Wu, Zhilin; Yuste-Córdoba, Francisco J; Cintas, Pedro; Wu, Zhansheng; Boffa, Luisa; Mantegna, Stefano; Cravotto, Giancarlo

2018-01-01

This paper reports that ultrasonic (US) and hydrodynamic cavitation (HC) are efficient strategies for the environmental remediation of cork wastewater (CW). It is necessary to remove toxic, inhibitory or refractory organic matter from CW using physical and chemical techniques (pre-treatment) prior to performing conventional biological treatment. After this biological treatment, it is also critical to further decontaminate (post-treatment) in order to meet the discharge limitation. The pre-treatment of diluted CW using Fenton oxidation (FE) alone led to COD and polyphenol (PP) removal values of 30% and 61%, respectively, while HC and US resulted in 83-90% increases in COD reduction and 26-33% increases in PP reduction. Whereas 55% and 91% COD and PP removal were achieved using flocculation (Floc) alone, COD elimination was increased by a further 7-18% under HC and US. No noticeable improvement in PP elimination was observed. US did not enhance the Floc decontamination of the original concentrated CW, however, considerable quantities of white biofilm were surprisingly generated on the CW surface after the pre-treatment, thus indicating the improvement of biodegradability of the resulting liquid. In fact, the post-treatment stage, using FE alone after having filtered the biofilms, led to reductions of 53% in COD and 90% in PP. The HC and US protocols resulted in 26-34% increases in COD elimination. HC further enhanced PP elimination caused by FE, while US resulted in lower levels of PP elimination. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhancement of a UASB-septic tank performance for decentralised treatment of strong domestic sewage.

PubMed

Mahmoud, Nidal; van Lier, Jules B

2011-01-01

The possibility of enhancing the process performance of the UASB-septic tank for treating strong sewage in Palestine by means of inoculating the reactor with well adapted anaerobic sludge and/or adding a packing media to the upper part of the reactor, creating an anaerobic hybrid (AH)-septic tank, was investigated. To achieve these objectives, two community onsite UASB-septic tank and AH-septic tank were operated in parallel at 2 days HRT for around 8 months overlapping the cold and hot periods of the year in Palestine. The achieved removal efficiencies of CODtot in the UASB-septic tank and AH-septic tank during the first months of operation, coinciding with the cold period and the subsequent hot period, were respectively 50 (+/- 15)% and 48 (+/- 15)% and 66 (+/- 8)% and 55 (+/- 8)%. This shows that the UASB-septic tank performed significantly better (p < 0.05) than the AH-septic tank after rather long periods of operation. The difference in the CODtot removal efficiency was mainly due to the better CODss removal efficiencies in the UASB-septic tank. The removal efficiencies over the last 50 days of operation for CODtot, CODsus, CODcol and CODdis were 70, 72, 77 and 55% and 53, 54, 78 and 45% for the UASB-septic tank and AH-septic tank, respectively. Comparing the here achieved COD removal efficiencies with previously reported efficiencies of UASB-septic tanks operated in Palestine shows that the reactor performance in terms of COD removal and conversion, during the first 8 months of operation, has improved substantially by being started with well adapted anaerobic sludge, simulating and predicting long-term performance. Adding packing media did not lead to an improvement.

Formation and hydrodynamic characteristics of aerobic granules in an activated sludge system.

PubMed

Ganesan, M V; Saravanan, V; Sreekrishnan, T R

2007-02-01

Development of aerobic granules in the aeration tank of an activated sludge system has been studied. The introduction of activated carbon particles into the aeration tank resulted in the formation of biogranules containing activated carbon as core nuclei. The presence of activated carbon also induced the formation of self-immobilized granules, which did not have any carrier particle at their core. The presence of aerobic granules enhanced the treatment efficiency of the reactor. At an organic loading rate of 32.8 kg COD m(-3)d(-1) and 0.78 h hydraulic retention time (HRT), the reactor showed 96% COD removal efficiency. At an HRT of 0.272 h and organic loading rate of 46.7 kg COD m(-3)d(-1), the reactor outlet COD remained below 100 mg l(-1). Settling velocity studies carried out on the biogranules showed that the drag coefficient of biogranules is greater than that of the rigid particle at the same Reynolds number.

Potential for methane production from anaerobic co-digestion of swine manure with winery wastewater.

PubMed

Riaño, B; Molinuevo, B; García-González, M C

2011-03-01

This work examines the methane production potential for the anaerobic co-digestion of swine manure (SM) with winery wastewater (WW). Batch and semi-continuous experiments were carried out under mesophilic conditions. Batch experiments revealed that the highest specific methane yield was 348 mL CH(4)g(-1) COD added, obtained at 85.4% of WW and 0.7 g COD g(-1)VS. Specific methane yield from SM alone was 27 mL CH(4)g(-1) COD added d(-1). Furthermore, specific methane yields were 49, 87 and 107 mL CH(4)g(-1) COD added d(-1) for the reactors co-digesting mixtures with 10% WW, 25% WW and 40% WW, respectively. Co-digestion with 40% WW improved the removal efficiencies up to 52% (TCOD), 132% (SCOD) and 61% (VSS) compared to SM alone. These results suggest that methane can be produced very efficiently by the co-digestion of swine manure with winery wastewater. Copyright © 2011 Elsevier Ltd. All rights reserved.

Removing organic matter from sulfate-rich wastewater via sulfidogenic and methanogenic pathways.

PubMed

Vilela, Rogerio Silveira; Damianovic, Márcia Helena Rissato Zamariolli; Foresti, Eugenio

2014-01-01

The simultaneous organic matter removal and sulfate reduction in synthetic sulfate-rich wastewater was evaluated for various chemical oxygen demand (COD)/sulfate ratios applied in a horizontal-flow anaerobic immobilized sludge (HAIS) reactor. At higher COD/sulfate ratios (12.5 and 7.5), the removal of organic matter was stable, likely due to methanogenesis. A combination of sulfate reduction and methanogenesis was clearly established at COD/sulfate ratios of 3.0 and 1.9. At a COD/sulfate ratio of 1.0, the organic matter removal was likely influenced by methanogenesis inhibition. The quantity of sulfate removed at a COD/sulfate ratio of 1.0 was identical to that obtained at a ratio of 1.9, indicating a lack of available electron donors for sulfidogenesis. The sulfate reduction and organic matter removal were not maximized at the same COD/sulfate ratio; therefore, competitive inhibition must be the predominant mechanism in establishing an electron flow.

Treatment and Energy Valorisation of an Agro-Industrial Effluent in Upflow Anaerobic Sludge Reactor (UASB)

NASA Astrophysics Data System (ADS)

Martins, Ramiro; Boaventura, Rui; Paulista, Larissa

2017-12-01

The accelerated growth of the population brings with it an increase in the generation of agro-industrial effluents. The inadequate discharge of these effluents significantly affects the quality of water resources. In this way, it becomes important to invest in treatment processes for agro-industrial effluents, particularly low-cost ones. In this context, the present study includes the design and construction of an UASB reactor and optimization of the anaerobic digestion treatment of the raw effluent from sweet chestnut production in the agro-industrial company Sortegel. The efficiency of the system was evaluated through the determination / monitoring of oxygen chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), biogas production rate and quality (% methane). The reactor was fed for 25 weeks and operated under mesophilic conditions (temperature 30-40 °C). Different values were tested for the hydraulic retention time (HRT) and volumetric flow rate (VF): 0.66 days (VF=1509 L.m-3.d-1); 1.33 days (VF=755 L.m-3.d-1); 2.41 d days (VF=415 L.m-3.d-1). The average COD removal efficiency reached values of 69%, 82% and 75%, respectively, and simultaneously the associated BOD5 removal efficiency was 84%, 91% and 70%. As regards TSS, removal values were 78%, 94% and 63%. In addition, high methane production rates were obtained, between 2500 and 4800 L CH4.kg-1 COD removed d-1. For all the hydraulic retention times tested, high concentrations of methane in the biogas were recorded: 66-75%, 70% and 75% for HRT of 0.66, 1.33 and 2.41 days, respectively.

An anaerobic-aerobic sequential batch process with simultaneous methanogenesis and short-cut denitrification for the treatment of marine biofoulings.

PubMed

Akizuki, S; Toda, T

2018-04-01

Although combination of denitritation and methanogenesis for wastewater treatment has been widely investigated, an application of this technology to solid waste treatment has been rarely studied. This study investigated an anaerobic-aerobic batch system with simultaneous denitritation-methanogenesis as an effective treatment for marine biofoulings, which is a major source of intermittently discharged organic solid wastes. Preliminary NO 2 - -exposed sludge was inoculated to achieve stable methanogenesis process without NO 2 - inhibition. Both high NH 4 + -N removal of 99.5% and high NO 2 - -N accumulation of 96.4% were achieved on average during the nitritation step. Sufficient CH 4 recovery of 101 L-CH 4 kg-COD -1 was achieved, indicating that the use of NO 2 - -exposed sludge is effective to avoid NO 2 - inhibition on methanogenesis. Methanogenesis was the main COD utilization pathway when the substrate solubilization occurred actively, while denitritation was the main when solubilization was limited because of substrate shortage. The results showed a high COD removal efficiency of 96.0% and a relatively low nitrogen removal efficiency of 64.4%. Fitting equations were developed to optimize the effluent exchange ratio. The estimated results showed that the increase of effluent exchange ratio during the active solubilization period increased the nitrogen removal efficiency but decreased CH 4 content in biogas. An appropriate effluent exchange ratio with high anaerobic effluent quality below approximately 120 mg-N L -1 as well as sufficient CH 4 gas quality which can be used as fuel for gas engine generator was achieved by daily effluent exchange of 80% during the first week and 5% during the subsequent 8 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal Efficiency of Electrocoagulation Treatment Using Aluminium Electrode for Stabilized Leachate

NASA Astrophysics Data System (ADS)

Mohamad Zailani, L. W.; Amdan, N. S. Mohd; Zin, N. S. M.

2018-04-01

This research was conducted to investigate the performance of aluminium electrode in electrocoagulation process removing chemical oxygen demand (COD), ammonia, turbidity, colour and suspended solid (SS) from Simpang Renggam landfill leachate. Effects of current density, electrolysis duration and pH were observed in this study. From the data obtained, optimum condition at current density was recorded at 200 A/m2with the electrolysis duration of 20-minutes and optimum pH value at 4. The removal recorded at this condition for COD, ammonia, colour, turbidity and suspended solid were 60%, 37%, 94%, 88% and 89% respectively. Electrocoagulation treatment give a better result and can be applied for leachate treatment in future. Thus, electrocoagulation treatment has the potential to be used in treatment of leachate.

Landfill leachate treatment using a rotating biological contactor and an upward-flow anaerobic sludge bed reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castillo, E.; Vergara, M.; Moreno, Y.

2007-07-01

This paper describes the feasibility of an aerobic system (rotating biological contactor, RBC) and a biological anaerobic system (upward-flow anaerobic sludge bed reactor) at small scale for the treatment of a landfill leachate. In the first phase of the aerobic system study, a cyclic-batch RBC system was used to select perforated acetate discs among three different acetate disc configurations. These discs were chosen on the basis of high COD removal (65%) and biological stability. In the second phase, the RBC system (using four stages) was operated continuously at different hydraulic retention times (HRT), at different rotational speeds, and with varyingmore » organic concentrations of the influent leachate (2500-9000 mg L{sup -1}). Forty percent of the total surface area of each perforated disc was submerged in the leachate. A COD removal of about 52% was obtained at an HRT of 24 h and a rotational speed of 6 rpm. For the anaerobic system, the reactor was evaluated with a volumetric organic load of 3273 g-COD m{sup -3} day{sup -1} at an HRT of 54, 44, 39, 24 and 17 h. At these conditions, the system reached COD removal efficiencies of 62%, 61%, 59%, 44% and 24%, respectively.« less

Extraction of antioxidants from olive mill wastewater and electro-coagulation of exhausted fraction to reduce its toxicity on anaerobic digestion.

PubMed

Khoufi, Sonia; Aloui, Fathi; Sayadi, Sami

2008-03-01

Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive mill wastewater (OMW), a polluting by-product of olive oil production process, and to reduce their toxicity for a subsequent aerobic or anaerobic digestion. Phenolic compounds were identified in untreated and treated OMW by gas chromatography coupled to mass spectrometry (GC-MS). The experimental results of ethyl acetate extraction showed that the monomers recovery efficiency was over 90%. This pre-treatment resulted in the removal of the major LMM phenolic compounds and a small part of HMM polyphenols. The aerobic treatment of the exhausted OMW fraction removed 78.7% of the soluble COD. In the case of anaerobic digestion at OLR ranged from 1 to 3.5 gCOD l(-1)day(-1), methanisation process exhibited high methane yield as 0.3 l CH4 produced per g COD introduced and high COD removal (80%). However, a disruption of the process was observed when the OLR was increased to 4.5 gCODl(-1)day(-1). A pre-treatment by electro-coagulation resulted in decreasing the toxicity and enhancing the performance of methanisation operated at higher OLR from 4 to 7.5 gCODl(-1)day(-1).

Treatment of kraft evaporator condensate using a thermophilic submerged anaerobic membrane bioreactor.

PubMed

Liao, B Q; Xie, K; Lin, H J; Bertoldo, Daniel

2010-01-01

The feasibility of using a thermophilic submerged anaerobic membrane bioreactor (SAnMBR) for kraft evaporator condensate treatment was studied at 55+/-1 degrees C over 6.5 months. Under tested organic loading rate of 1-7 kg COD/m(3) day, a soluble COD removal efficiency of 85-97% was obtained. The methane production rate was 0.35+/-0.1 L methane/g COD and the produced biogas was of excellent fuel quality with 80-90% methane. A higher membrane fouling rate was related to the presence of a larger portion of fine colloidal particles (1-10 mum). The thermophilic SAnMBR was sensitive to the presence of toxic compounds in feed and unexpected pH probe failure (leading to a higher pH). Feed toxic shock caused sludge deflocculation and thus deteriorated membrane performance. Operating the reactor as a conventional anaerobic reactor to waste some of the fine flocs in treated effluent during the start-up process was an effective strategy to reduce membrane fouling. The experimental results from this study indicate that treatment of kraft evaporator condensate is feasible in terms of COD removal and biogas production using thermophilic SAnMBRs but pre-treatment may be needed to remove toxic sulfur compounds and membrane fouling caused by the large portion of fine particles may be a challenge.

Treatment of winery wastewater by an anaerobic sequencing batch reactor.

PubMed

Ruíz, C; Torrijos, M; Sousbie, P; Lebrato Martínez, J; Moletta, R; Delgenès, J P

2002-01-01

Treatment of winery wastewater was investigated using an anaerobic sequencing batch reactor (ASBR). Biogas production rate was monitored and permitted the automation of the bioreactor by a simple control system. The reactor was operated at an organic loading rate (ORL) around 8.6 gCOD/L.d with soluble chemical oxygen demand (COD) removal efficiency greater than 98%, hydraulic retention time (HRT) of 2.2 d and a specific organic loading rate (SOLR) of 0.96 gCOD/gVSS.d. The kinetics of COD and VFA removal were investigated for winery wastewater and for simple compounds such as ethanol, which is a major component of winery effluent, and acetate, which is the main volatile fatty acid (VFA) produced. The comparison of the profiles obtained with the 3 substrates shows that, overall, the acidification of the organic matter and the methanisation of the VFA follow zero order reactions, in the operating conditions of our study. The effect on the gas production rate resulted in two level periods separated by a sharp break when the acidification stage was finished and only the breaking down of the VFA continued.

Removal of organic matter and ammonia nitrogen from landfill leachate by ultrasound.

PubMed

Wang, Songlin; Wu, Xiaohui; Wang, Yansong; Li, Qifen; Tao, Meijun

2008-09-01

Experiments on the removal of organic matters and ammonia nitrogen from landfill leachate by ultrasound irradiation were carried out. The effects of COD reduction and ammonia removal of power input, initial concentration, initial pH and aeration were studied. It was found that the sonolysis of organic matters proceeds via reaction with ()OH radicals; a thermal reaction also occurs with a small contribution. The rise of COD at some intervals could be explained by the complexity of organic pollutant sonolysis in landfill leachate. Ultrasonic irradiation was shown to be an effective method for the removal of ammonia nitrogen from landfill leachate. After 180 min ultrasound irradiation, up to 96% ammonia nitrogen removal efficiency can be obtained. It was found that the mechanism of ammonia nitrogen removal by ultrasound irradiation is largely that the free ammonia molecules in leachate enter into the cavitation bubbles and transform into nitrogen molecules and hydrogen molecules via pyrolysis under instant high temperature and high pressure in the cavitation bubbles.

Organic semiconductor wastewater treatment using a four-stage Bardenpho with membrane system.

PubMed

Chung, Jinwook; Fleege, Daniel; Ong, Say Kee; Lee, Yong-Woo

2014-01-01

Electronic wastewater from a semiconductor plant was treated with a pilot-scale four-stage Bardenpho process with membrane system. The system was operated over a 14-month period with an overall hydraulic retention time (HRT) ranging from 9.5 to 30 h. With a few exceptions, the pilot plant consistently treated the electronic wastewater with an average removal efficiency of chemical oxygen demand (COD) and total nitrogen of 97% and 93%, respectively, and achieving effluent quality of COD<15 mg/L, turbidity<1, and silt density index<1. Based on removal efficiencies of the pilot plant, it is possible to lower the HRT to less than 9.5 h to achieve comparable removal efficiencies. An energy-saving configuration where an internal recycle line was omitted and the biomass recycle was rerouted to the pre-anoxic tank, can reduce energy consumption by 8.6% and gave removal efficiencies that were similar to the Bardenpho process. The system achieved pre-anoxic and post-anoxic specific denitrification rate values with a 95% confidence interval of 0.091 ± 0.011 g NO₃-N/g MLVSS d and 0.087 ± 0.016 g NO₃-N/g MLVSS d, respectively. The effluent from the four-stage Bardenpho with membrane system can be paired with a reverse osmosis system to provide further treatment for reuse purposes.

[Energy saving achieved by limited filamentous bulking under low dissolved oxygen: experimental validation in A/O process].

PubMed

Guo, Jian-hua; Wang, Shu-ying; Peng, Yong-zhen; Zheng, Ya-nan; Huang, Hui-jun; Ge, Shi-jian; Sun, Zhi-rong

2008-12-01

Preliminary studies had been conducted to determine the correctness of the theory and technique of energy saving achieved by limited filamentous bulking under low DO using a lab-scale A/O reactor with real domestic wastewater as the influent. The results showed that SVI could be maintained 150-230 mL/g and sludge settleability would not become very poor under the condition of low DO. During the period of limited filamentous bulking, COD and total nitrogen removal efficiencies were improved, and distinct simultaneous nitrification and denitrification (SND) was achieved, while ammonia removal efficiency would slightly decline with decreasing of DO, compared with the period of good settleability sludge under high DO. COD, ammonia and total nitrogen removal efficiencies were 86%, 70% and 63%, respectively. It was found that about 10%-25% nitrogen would be removed by SND based on the mass balance of nitrogen. Besides, SS in the effluent was almost negligible and the effluent turbidity was lower than 3 NTU. Significantly, aeration consumptions would be decreased by 17% under the condition with DO of 0.5 mg/L compared with 2.0 mg/L according to theoretical calculation of air requirements to keep different DO levels, which was about 57% in lab-scale reactor correspondingly.

Combined coagulation-flocculation and sequencing batch reactor with phosphorus adjustment for the treatment of high-strength landfill leachate: experimental kinetics and chemical oxygen demand fractionation.

PubMed

El-Fadel, M; Matar, F; Hashisho, J

2013-05-01

The treatability of high-strength landfill leachate is challenging and relatively limited. This study examines the feasibility of treating high-strength landfill leachate (chemical oxygen demand [COD]: 7,760-11,770 mg/L, biochemical oxygen demand [BOD5]: 2,760-3,569 mg/L, total nitrogen [TN] = 980-1,160 mg/L) using a sequencing batch reactor (SBR) preceded by a coagulation-flocculation process with phosphorus nutritional balance under various mixing and aeration patterns. Simulations were also conducted to define kinetic parameters and COD fractionation. Removal efficiencies reached 89% for BOD5, 60% for COD, and 72% for TN, similar to and better than reported studies, albeit with a relatively lower hydraulic retention time (HRT) and solid retention time (SRT). The coupled experimental and simulation results contribute in filling a gap toward managing high-strength landfill leachate and providing guidelines for corresponding SBR applications. The treatability of high-strength landfill leachate, which is challenging and relatively limited, was demonstrated using a combined coagulation-flocculation with SBR technology and nutrient balance adjustment. The most suitable coagulant, kinetic design parameters, and COD fractionation were defined using coupled experimental and simulation results contributing in filling a gap toward managing high-strength leachate by providing guidelines for corresponding SBR applications and anticipating potential constraints related to the non-biodegradable COD fraction. In this context, while the combined coagulation-flocculation and SBR process improved removal efficiencies, posttreatment may be required for high-strength leachate, depending on discharge standards and ultimate usage of the treated leachate.

Effect of EDTA and Fe-EDTA complex concentration on TCF Kraft mill effluent degradability. Batch and continuous treatments.

PubMed

Diez, M C; Pouleurs, D; Navia, R; Vidal, G

2005-09-01

The effect of ethylenediaminetetracetic acid (EDTA) and Fe-EDTA complex on synthetic totally chlorine-free (TCF) effluent degradability in batch and continuously operating reactors was evaluated. Under batch treatment, the addition of EDTA and Fe-EDTA complex was studied in the range of 80 to 320 mg l(-1). Under continuously operated reactors, the Fe-EDTA complex concentration varied from 20 to 80 mg l(-1), and the hydraulic retention time (HRT) varied from 48 to 24 h. Sludge oxygen uptake rate (OUR) and chemical oxygen demand (COD) removal decreased when EDTA concentration increased in the influent under batch treatment; however, this inhibitory effect was reduced by the addition of Fe-EDTA complex. Without the addition of EDTA, COD removal decreased from 71% to 8%. The most efficient EDTA removal treatment (almost 10%) was the treatment of 80 mg l(-1) Fe-EDTA. Under continuously operated reactors, COD removal was greater than 57% in the synthetic TCF effluent with a Fe-EDTA concentration that varied from 20 to 80 mg l(-1); however, EDTA removal was lower than 25% in all cases. Synthetic TCF effluent with a Fe -EDTA concentration higher than 80 mg l(-1) could not be treated by the activated sludge treatment due to EDTA's inhibitory effect on the sludge.

Acetaminophen degradation by electro-Fenton and photoelectro-Fenton using a double cathode electrochemical cell.

PubMed

de Luna, Mark Daniel G; Veciana, Mersabel L; Su, Chia-Chi; Lu, Ming-Chun

2012-05-30

Acetaminophen is a widely used drug worldwide and is one of the most frequently detected in bodies of water making it a high priority trace pollutant. This study investigated the applicability of the electro-Fenton and photoelectro-Fenton processes using a double cathode electrochemical cell in the treatment of acetaminophen containing wastewater. The Box-Behnken design was used to determine the effects of initial Fe(2+) and H(2)O(2) concentrations and applied current density. Results showed that all parameters positively affected the degradation efficiency of acetaminophen with the initial Fe(2+) concentration being the most significant parameter for both processes. The acetaminophen removal efficiency for electro-Fenton was 98% and chemical oxygen demand (COD) removal of 43% while a 97% acetaminophen removal and 42% COD removal were observed for the photoelectro-Fenton method operated at optimum conditions. The electro-Fenton process was only able to obtain 19% total organic carbon (TOC) removal while the photoelectro-Fenton process obtained 20%. Due to negligible difference between the treatment efficiencies of the two processes, the electro-Fenton method was proven to be more economically advantageous. The models obtained from the study were applicable to a wide range of acetaminophen concentrations and can be used in scale-ups. Thirteen different types of intermediates were identified and a degradation pathway was proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

Sequential use of bentonites and solar photocatalysis to treat winery wastewater.

PubMed

Rodríguez, Eva; Márquez, Gracia; Carpintero, Juan Carlos; Beltrán, Fernando J; Alvarez, Pedro

2008-12-24

The sequential use of low-cost adsorbent bentonites and solar photocatalysis to treat winery wastewater has been studied. Three commercial sodium-bentonites (MB-M, MB-G, and MB-P) and one calcium-bentonite (Bengel) were characterized and used in this study. These clay materials were useful to totally remove turbidity (90-100%) and, to a lesser extent, color, polyphenols (PPh), and soluble chemical oxygen demand (CODS) from winery wastewater. Both surface area and cation exchange capacity (CEC) of bentonite had a positive impact on treatment efficiency. The effect of pH on turbidity removal by bentonites was studied in the 3.5-12 pH range. The bentonites were capable of greatly removing turbidity from winery wastewater at pH 3.5-5.5, but removal efficiency decreased with pH increase beyond this range. Settling characteristics (i.e., sludge volume index (SVI) and settling rate) of bentonites were also studied. Best settling properties were observed for bentonite doses around 0.5 g/L. The reuse of bentonite for winery wastewater treatment was found not to be advisable as the turbidity and PPh removal efficiencies decreased with successive uses. The resulting wastewater after bentonite treatment was exposed to solar radiation at oxic conditions in the presence of Fe(III) and Fe(III)/H2O2 catalysts. Significant reductions of COD, total organic carbon (TOC), and PPh were achieved by these solar photocatalytic processes.

Nitrogen removal performance of anaerobic ammonia oxidation (ANAMMOX) in presence of organic matter.

PubMed

Zhu, Weiqiang; Zhang, Peiyu; Yu, Deshuang; Dong, Huiyu; Li, Jin

2017-06-01

A sequencing batch reactor (SBR) was used to test the nitrogen removal performance of anaerobic ammonium oxidation (ANAMMOX) in presence of organic matter. Mesophilic operation (30 ± 0.5 °C) was performed with influent pH 7.5. The results showed, independent of organic matter species, ANAMMOX reaction was promoted when COD was lower than 80 mg/L. However, specific ANAMMOX activity decreased with increasing organic matter content. Ammonium removal efficiency decreased to 80% when COD of sodium succinate, sodium potassium tartrate, peptone and lactose were 192.5, 210, 225 and 325 mg/L, respectively. The stoichiometry ratio resulting from different OM differed largely and R 1 could be as an indicator for OM inhibition. When COD concentration was 240 mg/L, the loss of SAA resulting from lactose, peptone, sodium potassium tartrate and sodium succinate were 28, 36, 50 and 55%, respectively. Sodium succinate had the highest inhibitory effect on SAA. When ANAMMOX process was used to treat wastewater containing OM, the modified Logistic model could be employed to predict the NRE max .

Palm oil mill effluent treatment using a two-stage microbial fuel cells system integrated with immobilized biological aerated filters.

PubMed

Cheng, Jia; Zhu, Xiuping; Ni, Jinren; Borthwick, Alistair

2010-04-01

An integrated system of two-stage microbial fuel cells (MFCs) and immobilized biological aerated filters (I-BAFs) was used to treat palm oil mill effluent (POME) at laboratory scale. By replacing the conventional two-stage up-flow anaerobic sludge blanket (UASB) with a newly proposed upflow membrane-less microbial fuel cell (UML-MFC) in the integrated system, significant improvements on NH(3)-N removal were observed and direct electricity generation implemented in both MFC1 and MFC2. Moreover, the coupled iron-carbon micro-electrolysis in the cathode of MFC2 further enhanced treatment efficiency of organic compounds. The I-BAFs played a major role in further removal of NH(3)-N and COD. For influent COD and NH(3)-N of 10,000 and 125 mg/L, respectively, the final effluents COD and NH(3)-N were below 350 and 8 mg/L, with removal rates higher than 96.5% and 93.6%. The GC-MS analysis indicated that most of the contaminants were satisfactorily biodegraded by the integrated system. Copyright 2009 Elsevier Ltd. All rights reserved.

Treatment of crystallized-fruit wastewater by UV-A LED photo-Fenton and coagulation-flocculation.

PubMed

Rodríguez-Chueca, Jorge; Amor, Carlos; Fernandes, José R; Tavares, Pedro B; Lucas, Marco S; Peres, José A

2016-02-01

This work reports the treatment of crystallized-fruit effluents, characterized by a very low biodegradability (BOD5/COD <0.19), through the application of a UV-A LED photo-Fenton process. Firstly, a Box-Behnken design of Response Surface Methodology was applied to achieve the optimal conditions for the UV-A LED photo-Fenton process, trying to maximize the efficiency by saving chemicals and time. Under the optimal conditions ([H2O2] = 5459 mg/L; [Fe(3+)] = 286 mg/L; time >180 min), a COD removal of 45, 64 and 74% was achieved after 360 min, using an irradiance of 23, 70 and 85 W/m(2) respectively. Then a combination of UV-A LED photo-Fenton with coagulation-flocculation-decantation attained a higher COD removal (80%), as well as almost total removal of turbidity (99%) and total suspended solids (95%). Subsequent biodegradability of treated effluents increased, allowing the application of a biological treatment step after the photochemical/CFD with 85 W/m(2). Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource.

PubMed

Li, Yu-Long; Wang, Jin; Yue, Zheng-Bo; Tao, Wei; Yang, Hai-Bin; Zhou, Yue-Fei; Chen, Tian-Hu

2017-07-01

Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO 4 2- mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO 4 2- ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Performance of double-layer biofilter packed with coal fly ash ceramic granules in treating highly polluted river water.

PubMed

Jing, Zhaoqian; Li, Yu-You; Cao, Shiwei; Liu, Yuyu

2012-09-01

To improve trickling filters' denitrification efficiency, a biofilter with a trickling upper layer and a submerged lower layer was developed and applied in treating highly polluted river water. It was packed with porous coal fly ash ceramic granules. Its start-up characteristics, influence of hydraulic loading rates (HLR), carbon/nitrogen (C/N) ratio and filter depth on pollutants removal were investigated. The results indicated this biofilter was started quickly in 16 days with river sediment as inoculum. Alternating nitrification and denitrification were achieved when water flowed downwards. COD and nitrogen were mainly removed in the upper layer and the lower layer, respectively. With HLR of 4.0-5.0m(3)/(m(2)d), chemical oxygen demand (COD), ammonium (NH(4)(+)-N) and total nitrogen (TN) in the effluent were below 50, 5 and 15 mg/L, respectively. This biofilter removed more than 80% of COD, 85% of NH(4)(+)-N and 60% of TN with C/N ratios ranging from 6 to 10. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biodegradation of organics in landfill leachate by immobilized white rot fungi, Trametes versicolor BCC 8725.

PubMed

Saetang, Jenjira; Babel, Sandhya

2012-12-01

Immobilized Trametes versicolor BCC 8725 was evaluated for the biodegradation of the organic components of four different types of landfill leachate collected at different time periods and locations from the Nonthaburi landfill site of Thailand in batch treatment. The effects of carbon source, ammonia and organic loading on colour, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal, and the reuse of immobilized fungi were investigated. It was found that fungi can remove 78% of colour, reduce BOD by 68% and reduce COD by 57% in leachate within 15 days at optimum conditions. Organic loading and ammonia were the factors that affected the biodegradation. When immobilized T versicolor on polyurethane foam (PUF) was subjected to repeated use for treatment over the course of three cycles, the decolourization efficiency of the first and the second cycle was very similar, whereas the third cycle was about 20% lower than the first cycle under similar conditions. The obtained removal of colour, BOD and COD indicates the effectiveness of fungi for leachate treatment with high organic loading and varied leachate characteristics.

Influence of diligent disintegration on anaerobic biomass and performance of microbial fuel cell.

PubMed

Divyalakshmi, Palanisamy; Murugan, Devaraj; Rai, Chockalingam Lajapathi

2017-12-01

To enhance the performance of microbial fuel cells (MFC) by increasing the surface area of cathode and diligent mechanical disintegration of anaerobic biomass. Tannery effluent and anaerobic biomass were used. The increase in surface area of the cathode resulted in 78% COD removal, with the potential, current density, power density and coulombic efficiency of 675 mV, 147 mA m -2 , 33 mW m -2 and 3.5%, respectively. The work coupled with increased surface area of the cathode with diligent mechanical disintegration of the biomass, led to a further increase in COD removal of 82% with the potential, current density, power density and coulombic efficiency of 748 mV, 229 mA m -2 , 78 mW m -2 and 6% respectively. Mechanical disintegration of the biomass along with increased surface area of cathode enhances power generation in vertical MFC reactors using tannery effluent as fuel.

Semi-aerobic stabilized landfill leachate treatment by ion exchange resin: isotherm and kinetic study

NASA Astrophysics Data System (ADS)

Zamri, Mohd Faiz Muaz Ahmad; Kamaruddin, Mohamad Anuar; Yusoff, Mohd Suffian; Aziz, Hamidi Abdul; Foo, Keng Yuen

2017-05-01

This study was carried out to investigate the treatability of ion exchange resin (Indion MB 6 SR) for the removal of chromium (VI), aluminium (III), zinc (II), copper (II), iron (II), and phosphate (PO4)3-, chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and colour from semi-aerobic stabilized leachate by batch test. A range of ion exchange resin dosage was tested towards the removal efficiency of leachate parameters. It was observed that equilibrium data were best represented by the Langmuir model for metal ions and Freundlich was ideally fit for COD, NH3-N and colour. Intra particle diffusion model, pseudo first-order and pseudo second-order isotherm models were found ideally fit with correlation of the experimental data. The findings revealed that the models could describe the ion exchange kinetic behaviour efficiently, which further suggests comprehensive outlook for the future research in this field.

Comparison of biomass from integrated fixed-film activated sludge (IFAS), moving bed biofilm reactor (MBBR) and membrane bioreactor (MBR) treating recalcitrant organics: Importance of attached biomass.

PubMed

Huang, Chunkai; Shi, Yijing; Xue, Jinkai; Zhang, Yanyan; Gamal El-Din, Mohamed; Liu, Yang

2017-03-15

This study compared microbial characteristics and oil sands process-affected water (OSPW) treatment performance of five types of microbial biomass (MBBR-biofilm, IFAS-biofilm, IFAS-floc, MBR-aerobic-floc, and MBR-anoxic-floc) cultivated from three types of bioreactors (MBBR, IFAS, and MBR) in batch experiments. Chemical oxygen demand (COD), ammonium, acid extractable fraction (AEF), and naphthenic acids (NAs) removals efficiencies were distinctly different between suspended and attached bacterial aggregates and between aerobic and anoxic suspended flocs. MBR-aerobic-floc and MBR-anoxic-floc demonstrated COD removal efficiencies higher than microbial aggregates obtained from MBBR and IFAS, MBBR and IFAS biofilm had higher AEF removal efficiencies than those obtained using flocs. MBBR-biofilm demonstrated the most efficient NAs removal from OSPW. NAs degradation efficiency was highly dependent on the carbon number and NA cyclization number according to UPLC/HRMS analysis. Mono- and di-oxidized NAs were the dominant oxy-NA species in OSPW samples. Microbial analysis with quantitative polymerase chain reaction (q-PCR) indicated that the bacterial 16S rRNA gene abundance was significantly higher in the batch bioreactors with suspended flocs than in those with biofilm, the NSR gene abundance in the MBR-anoxic bioreactor was significantly lower than that in aerobic batch bioreactors, and denitrifiers were more abundant in the suspended phase of the activated sludge flocs. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel technique of semi-aerobic aged refuse biofilter for leachate treatment.

PubMed

Han, Zhi-Yong; Liu, Dan; Li, Qi-Bin; Li, Gui-Zhi; Yin, Zhao-Yang; Chen, Xin; Chen, Jian-Nan

2011-08-01

We developed a semi-aerobic aged refuse biofilter (SAARB) for leachate treatment and examined its advantages and disadvantages compared to previous aged refuse biofilters (ARBs). To assess its treatment capability, decontamination mechanisms and optimal performance parameters, a single-period experiment and L(9)(3(4)) orthogonal array design experiments were conducted on artificial leachate. The SAARB markedly enhanced the treatment capability and removal efficiency of organic matter and nitrogen pollutants due to the alternating aerobic-anoxic-anaerobic zones in situ. The reduction in chemical oxygen demand (COD), ammonia nitrogen (NH(4)(+)-N) and total nitrogen (TN) exceeded 98%, 94%, and 80%, respectively. After the leachate was distributed onto the SAARB surface, the effluent velocity decreased as a logarithmic function, and there was a concomitant reduction in leachate effluent volume. Based on the capacity for removal of COD, NH(4)(+)-N, and TN, the effective height of aged refuse in a SAARB was enough to be 900mm. An excellent treatment efficiency could be achieved at 20-35°C, with a leachate distribution time of 1h once every period of 2-3 days, hydraulic loading of 11-30L/(m(3)day), and COD loading of 550-1200g/(m(3)day). This new SAARB system demonstrates superior efficacy for biofilter compared to other ARB systems, especially for nitrogen removal from leachate. Copyright © 2011 Elsevier Ltd. All rights reserved.

Removal of veterinary antibiotics from anaerobically digested swine wastewater using an intermittently aerated sequencing batch reactor.

PubMed

Zheng, Wei; Zhang, Zhenya; Liu, Rui; Lei, Zhongfang

2018-03-01

A lab-scale intermittently aerated sequencing batch reactor (IASBR) was applied to treat anaerobically digested swine wastewater (ADSW) to explore the removal characteristics of veterinary antibiotics. The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand (COD) volumetric loadings, solid retention times (SRT) and ratios of COD to total nitrogen (TN) or COD/TN. Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics. Mass balance analysis revealed that greater than 60% of antibiotics in the influent were biodegraded in the IASBR, whereas averagely 24% were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium. Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand (COD) volumetric loadings, which could achieve up to 85.1%±1.4% at 0.17±0.041kgCOD/m -3 /day, while dropped to 75.9%±1.3% and 49.3%±12.1% when COD volumetric loading increased to 0.65±0.032 and 1.07±0.073kgCOD/m -3 /day, respectively. Tetracyclines, the dominant antibiotics in ADSW, were removed by 87.9% in total at the lowest COD loading, of which 30.4% were contributed by sludge sorption and 57.5% by biodegradation, respectively. In contrast, sulfonamides were removed about 96.2%, almost by biodegradation. Long SRT seemed to have little obvious impact on antibiotics removal, while a shorter SRT of 30-40day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge. Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work. Copyright © 2017. Published by Elsevier B.V.

Study on nitrogen removal enhanced by shunt distributing wastewater in a constructed subsurface infiltration system under intermittent operation mode.

PubMed

Li, Yinghua; Li, Haibo; Sun, Tieheng; Wang, Xin

2011-05-15

Subsurface wastewater infiltration system is an efficient and economic technology in treating small scattered sewage. The removal rates are generally satisfactory in terms of COD, BOD(5), TP and SS removal; while nitrogen removal is deficient in most of the present operating SWIS due to the different requirements for the presence of oxygen for nitrification and denitrification processes. To study the enhanced nitrogen removal technologies, two pilot subsurface wastewater infiltration systems were constructed in a village in Shenyang, China. The filled matrix was a mixture of 5% activated sludge, 65% brown soil and 30% coal slag in volume ratio for both systems. Intermittent operation mode was applied in to supply sufficient oxygen to accomplish the nitrification; meanwhile sewage was supplemented as the carbon source to the lower part in to denitrify. The constructed subsurface wastewater infiltration systems worked successfully under wetting-drying ratio of 1:1 with hydraulic loading of 0.081 m(3)/(m(2)d) for over 4 months. Carbon source was supplemented with shunt ratio of 1:1 and shunt position at the depth of 0.5m. The experimental results showed that intermittent operation mode and carbon source supplementation could significantly enhance the nitrogen removal efficiency with little influence on COD and TP removal. The average removal efficiencies for NH(3)-N and TN were 87.7 ± 1.4 and 70.1 ± 1.0%, increased by 12.5 ± 1.0 and 8.6 ± 0.7%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Investigation of Oxidation Methods for Waste Soy Sauce Treatment

PubMed Central

Jang, Hyun-Hee; Seo, Gyu-Tae

2017-01-01

To obtain a suitable oxidation method for removing the color and lowering the chemical oxygen demand (COD) of waste soy sauce, Fenton (Fe2+), Fenton-like (Fe3+), and ozone (O3) oxidation methods are used as the target reactions. In experimental conditions for Fenton oxidation, the dose of Fe2+ and Fe3+ was varied between 100 mg/L and 300 mg/L. The dose of hydrogen peroxide for the reaction was injected from 100–1000 mg/L. For ozone oxidation, the pH was increased from 3 to 14 and the O3-containing gas was supplied continuously for 30 min through a gas diffuser at the bottom of the reactor at different applied O3 doses (10–90 mg/L). We subjected it to a simple 1:20 dilution with deionized water to identify the comparison result in detail. O3 oxidation shows the highest efficiencies of color removal (81.1%) and COD lowering (64.9%) among the three oxidation methods. This is mainly due to the fact that it has a relatively large amount of hydroxyl radical, resulting in the degradation of organics. Thus, O3 oxidation could be a promising method for removing the color and lowering the COD of waste soy sauce. The critical parameters (pH and applied O3 dose) were varied systematically to optimize O3 oxidation. It was found that the optimum pH and applied O3 dose are 11.0 mg /L and 50.0 mg /L, respectively (color removal = 34.2%, COD removal = 27.4%). PMID:28991163

Pecan shell-based granular activated carbon for treatment of chemical oxygen demand (COD) in municipal wastewater.

PubMed

Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

2004-09-01

The present investigation was undertaken to compare the adsorption efficiency of pecan shell-based granular activated carbon with the adsorption efficiency of the commercial carbon Filtrasorb 200 with respect to uptake of the organic components responsible for the chemical oxygen demand (COD) of municipal wastewater. Adsorption efficiencies for these two sets of carbons (experimental and commercial) were analyzed by the Freundlich adsorption model. The results indicate that steam-activated and acid-activated pecan shell-based carbons had higher adsorption for organic matter measured as COD, than carbon dioxide-activated pecan shell-based carbon or Filtrasorb 200 at all the carbon dosages used during the experiment. The higher adsorption may be related to surface area as the two carbons with the highest surface area also had the highest organic matter adsorption. These results show that granular activated carbons made from agricultural waste (pecan shells) can be used with greater effectiveness for organic matter removal from municipal wastewater than a coal-based commercial carbon. Copyright 2004 Elsevier Ltd.

Performance assessment of aquatic macrophytes for treatment of municipal wastewater

PubMed Central

2014-01-01

The objective of the study was to evaluate the performance of three different aquatic macrophytes for treatment of municipal wastewater collected from Taxila (Pakistan). A physical model of treatment plant was constructed and was operated for six experimental runs with each species of macrophyte. Every experimental run consist of thirty days period. Regular monitoring of influent and effluent concentrations were made during each experimental run. For the treatment locally available macrophyte species i.e. water hyacinth, duckweed & water lettuce were selected to use. To evaluate the treatment performance of each macrophyte, BOD5, COD, and Nutrients (Nitrogen and Phosphorus) were monitored in effluent from model at different detention time of every experimental run after ensuring steady state conditions. The average reduction of effluent value of each parameter using water hyacinth were 50.61% for BOD5, 46.38% for COD, 40.34% for Nitrogen and 18.76% for Phosphorus. For duckweed the average removal efficiency for selected parameters were 33.43% for BOD5, 26.37% for COD, 17.59% for Nitrogen and 15.25% for Phosphorus and for Water Lettuce the average removal efficiency were 33.43% for BOD5, 26.37% for COD, 17.59% for Nitrogen and 15.25% for Phosphorus. The mechanisms of pollutant removal in this system include both aerobic and anaerobic microbiological conversions, sorption, sedimentation, volatilization and chemical transformations. The rapid growth of the biomass was measured within first ten days detention time. It was also observed that performance of macrophytes is influenced by variation of pH and Temperature. A pH of 6-9 and Temperature of 15-38°C is most favorable for treatment of wastewater by macrophytes. The option of macrophytes for treatment of Municipal sewage under local environmental conditions can be explored by further verifying the removal efficiency under variation of different environmental conditions. Also this is need of time that macrophyte system should be used for treatment of wastewater because their performance is comparable to conventional wastewater treatment plants and also the system has very low O&M costs. PMID:25089203

Application of food waste disposers and alternate cycles process in small-decentralized towns: a case study.

PubMed

Battistoni, Paolo; Fatone, Francesco; Passacantando, Daniele; Bolzonella, David

2007-02-01

The use of food waste disposers (FWDs) can be an interesting option to integrate the management of municipal wastewaters and household organic waste in small towns and decentralized areas. This strategy can be even more environmentally friendly if a suitable treatment process of the resulting sewage is performed in order to control nutrients emission. However, still nowadays, part of the scientific and technical community considers the application of this technology a possible source of problems. In this study, the FWDs were applied, with a market penetration factor of 67%, in a mountain village of 250 inhabitants. Further, the existing wastewater treatment plant (WWTP) was upgraded by applying an automatically controlled alternate cycles process for the management of nutrients removal. With specific reference to the observed results, the impact of the ground food waste on the sewerage system did not show particular solids sedimentation or significant hydraulic overflows. Further, the WWTP was able to face the overloads of 11, 55 and 2g per capita per day of TSS, COD and TN, respectively. Then, the increase of the readily biodegradable COD (rbCOD/COD from 0.20 to 0.25) and the favourable COD/TN ratio (from 9.9 to 12) led to a specific denitrification rate of some 0.06kgNO(3)-N/(kg MLVSS day). Therefore, not only COD removal, but also the total nitrogen removal increased: the denitrification efficiency reached 85%. That led to a better exploitation of the nitrogen-bound oxygen and a consequent reduction of energy requirements of 39%. The final economic evaluation showed the benefits of the application of this technology with a pay back time of 4-5 years.

Inhibitory effect of high NH4(+)-N concentration on anaerobic biotreatment of fresh leachate from a municipal solid waste incineration plant.

PubMed

Liu, Zhao; Dang, Yan; Li, Caihua; Sun, Dezhi

2015-09-01

Fresh leachate from municipal solid waste (MSW) incineration plants generally contains extremely high NH4(+)-N concentration which could inhibit the bioactivity of microorganisms. The inhibitory effect of high NH4(+)-N concentration on anaerobic biotreatment of fresh leachate from a MSW incineration plant in China has been investigated in this study. The inhibition processes was studied by both static tests and a laboratory-scale expanded granular sludge bed (EGSB) reactor. The specific methanogenic activity (SMA) of the microorganisms in anaerobic granular sludge was inhibited with the NH4(+)-N concentration increasing to 1000mg/L in static tests. As well the chemical oxygen demand (COD) removal efficiency and the methane yield decreased in the EGSB reactor, while the volatile fatty acids (VFAs) accumulated and extracellular polymeric substances (EPS) of the anaerobic granular sludge increased with NH4(+)-N concentration rising to 1000mg/L, without any rebounding during 30days of operation. Decreasing NH4(+)-N concentration to 500mg/L in influent, the COD removal efficiency recovered to about 85% after 26days. 1000mg/L of NH4(+)-N in leachate was suggested to be the inhibition threshold in EGSB reactor. High-throughput sequencing results showed little changes in microbial communities of the sludge for a high NH4(+)-N concentration, indicating that the survival of most microorganisms was not affected under such a condition. It inhibited the bioactivity of the microorganisms, resulting in decrease of the COD removal efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

Use of ozone in a pilot-scale plant for textile wastewater pre-treatment: physico-chemical efficiency, degradation by-products identification and environmental toxicity of treated wastewater.

PubMed

Somensi, Cleder A; Simionatto, Edésio L; Bertoli, Sávio L; Wisniewski, Alberto; Radetski, Claudemir M

2010-03-15

In this study, ozonation of raw textile wastewater was conducted in a pilot-scale plant and the efficiency of this treatment was evaluated based on the parameters color removal and soluble organic matter measured as chemical oxygen demand (COD), at two pH values (9.1 and 3.0). Identification of intermediate and final degradation products of ozone pre-treatment, as well as the evaluation of the final ecotoxicity (Lumistox test) of pre-treated wastewater, was also carried out. After 4h of ozone treatment with wastewater recirculation (flow rate of 0.45 m(3)h(-1)) the average efficiencies for color removal were 67.5% (pH 9.1) and 40.6% (pH 3.0), while COD reduction was 25.5% (pH 9.1) and 18.7% (pH 3.0) for an ozone production capacity of 20 g h(-1). Furthermore, ozonation enhances the biodegradability of textile wastewater (BOD(5)/COD ratios) by a factor of up to 6.8-fold. A GC-MS analysis of pre-treated textile wastewater showed that some products were present at the end of the pre-treatment time. In spite of this fact, the bacterial luminescence inhibition test (Lumistox test) showed a significant toxicity reduction on comparing the raw and treated textile wastewater. In conclusion, pre-ozonation of textile wastewater is an important step in terms of improving wastewater biodegradability, as well as reducing acute ecotoxicity, which should be removed completely through sequential biological treatment. (c) 2009. Published by Elsevier B.V.

Zero Liquid Discharge approach in plating industry: treatment of degreasing effluents by electrocoagulation and anodic oxidation.

PubMed

Hermon, S; Grange, D; Pellet, Y; Lloret, G; Oyonarte, S; Bosch, F; Coste, M

2008-01-01

Degreasing waste effluents issued from a surface treatment plant were treated by electrochemical techniques in an attempt to reduce COD so that clean water can be returned to the rinse bath. Electrocoagulation, both with iron and aluminium anodes, and anodic oxidation with boron doped diamond (BDD) anodes were tested. In the electrocoagulation tests, the nature of the anodes did not impact significantly the reduction of COD. Electrocoagulation showed good COD removal rates, superior to 80%, but it was not able to reduce COD down to low levels. Anodic oxidation was able to reduce COD down to discharge limits; the oxidation efficiency was superior to 50%. Economical calculations show that anodic oxidation is best used as a polishing step after electrocoagulation. The bulk of the COD would be reduced by electrocoagulation and, then, anodic oxidation would reduce COD below discharge limits. The maximum treatable flow is somewhat hindered by the small sizes of current BDD installation but it would reach 600 m(3)/year if anodic oxidation is coupled with electrocoagulation, the operational cost being 2.90 Euros /m(3). (c) IWA Publishing 2008.

The effect and biological mechanism of COD/TN ratio on nitrogen removal in a novel upflow microaerobic sludge reactor treating manure-free piggery wastewater.

PubMed

Li, Jianzheng; Meng, Jia; Li, Jiuling; Wang, Cheng; Deng, Kaiwen; Sun, Kai; Buelna, Gerardo

2016-06-01

A novel upflow microaerobic sludge reactor (UMSR) was constructed to treat manure-free piggery wastewater with high NH4(+)-N concentration and low COD/TN ratio, and the effect and biological mechanism of COD/TN ratio on nitrogen removal were investigated at a constant hydraulic retention time of 8h and 35°C. The results showed that the UMSR could treat the wastewater with a better synchronous removal of COD, NH4(+)-N and TN. The microaerobic UMSR allowed nitrifiers, and heterotrophic and autotrophic denitrifiers to thrive in the flocs, revealing a multiple nitrogen removal mechanism in the reactor. Both the nitrifiers and denitrifiers would be restricted by an influent COD/TN ratio more than 0.82, resulting in a decrease of TN removal in the UMSR. To get a TN removal over 80% with a TN load removal above 0.86kg/(m(3)·d) in the UMSR, the influent COD/TN ratio should be less than 0.70. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment.

PubMed

Cho, Kangwoo; Qu, Yan; Kwon, Daejung; Zhang, Hao; Cid, Clément A; Aryanfar, Asghar; Hoffmann, Michael R

2014-02-18

We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2(-)·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment.

Electricity generation from food wastes and microbial community structure in microbial fuel cells.

PubMed

Jia, Jianna; Tang, Yu; Liu, Bingfeng; Wu, Di; Ren, Nanqi; Xing, Defeng

2013-09-01

Microbial fuel cell (MFC) was studied as an alternate and a novel way to dispose food wastes (FWs) in a waste-to-energy form. Different organic loading rate obviously affected the performance of MFCs fed with FWs. The maximum power density of ~18 W/m(3) (~556 mW/m(2)) was obtained at COD of 3200±400 mg/L and the maximum coulombic efficiency (CE) was ~27.0% at COD of 4900±350 mg/L. The maximum removals of COD, total carbohydrate (TC) and total nitrogen (TN) were ~86.4%, ~95.9% and ~16.1%, respectively. Microbial community analysis using 454 pyrosequencing of 16S rRNA gene demonstrated the combination of the dominant genera of the exoelectrogenic Geobacter and fermentative Bacteroides effectively drove highly efficient and reliable MFC systems with functions of organic matters degradation and electricity generation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Investigation of titanium dioxide/ tungstic acid -based photocatalyst for human excrement wastewater treatment

NASA Astrophysics Data System (ADS)

Xu, Fei; Wang, Can; Xiao, Kemeng; Gao, Yufeng; Zhou, Tong; Xu, Heng

2018-05-01

An activated carbon (AC) coated with tungstic acid (WO3)/titanium dioxide (TiO2) nanocomposites photocatalytic material (ACWT) combined with Three-phase Fluidized Bed (TFB) was investigated for human excrement wastewater treatment. Under the ultraviolet (UV) and fluorescent lamp illumination, the ACWT had shown a good performance on chemical oxygen demand (COD) and total nitrogen (TN) removal but inefficient on ammonia nitrogen (NH3-N) removal. Optimized by Taguchi method, COD and TN removal efficiency was up to 88.39% and 55.07%, respectively. Among all the parameters, the dosage of ACWT had the largest contribution on the process. Bacterial community changes after treatment demonstrated that this photocatalytic system had a great sterilization effect on wastewater. These results confirmed that ACWT could be applied for the human excrement wastewater treatment.

Nitrogen removal on recycling water process of wastewater treatment plant effluent using subsurface horizontal wetland with continuous feed

NASA Astrophysics Data System (ADS)

Tazkiaturrizki, T.; Soewondo, P.; Handajani, M.

2018-01-01

Recycling water is a generic term for water reclamation and reuse to solve the scarcity of water. Constructed wetlands have been recognized as providing many benefits for wastewater treatment including water supply and control by recycling water. This research aims to find the best condition to significantly remove nitrogen using constructed wetland for recycling water of Bojongsoang Waste Water Treatment Plan (WWTP) effluent. Using media of soil, sand, gravel, and vegetation (Typha latifolia and Scirpus grossus) with an aeration system, BOD and COD parameters have been remarkably reduced. On the contrary, the removal efficiency for nitrogen is only between 50-60%. Modifications were then conducted by three step of treatment, i.e., Step I is to remove BOD/COD using Typha latifolia with an aeration system, Step II is todecrease nitrogen using Scirpus grossus with/without aeration, and Step III isto complete the nitrogen removal with denitrification process by Glycine max without aeration. Results of the research show that the nitrogen removal has been successfully increased to a high efficiency between 80-99%. The combination of aeration system and vegetation greatly affects the nitrogen removal. The vegetation acts as the organic nitrogen consumer (plant uptake) for amino acids, nitrate, and ammonium as nutrition, as well as theoxygen supplier to the roots so that aerobic microsites are formed for ammonification microorganisms.

Electrocoagulation and nanofiltration integrated process application in purification of bilge water using response surface methodology.

PubMed

Akarsu, Ceyhun; Ozay, Yasin; Dizge, Nadir; Elif Gulsen, H; Ates, Hasan; Gozmen, Belgin; Turabik, Meral

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box-Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5-15 V), initial pH (4.5-8.0) and time (30-90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P > 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R(2) and Radj(2) values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R(2) values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage-time and pH-time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology.

PubMed

Yang, Xiaoyi

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Hydrogen and lipid production from starch wastewater by co-culture of anaerobic sludge and oleaginous microalgae with simultaneous COD, nitrogen and phosphorus removal.

PubMed

Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Ren, Nanqi

2015-11-15

Anaerobic sludge (AS) and microalgae were co-cultured to enhance the energy conversion and nutrients removal from starch wastewater. Mixed ratio, starch concentration and initial pH played critical roles on the hydrogen and lipid production of the co-culture system. The maximum hydrogen production of 1508.3 mL L(-1) and total lipid concentration of 0.36 g L(-1) were obtained under the optimized mixed ratio (algae:AS) of 30:1, starch concentration of 6 g L(-1) and initial pH of 8. The main soluble metabolites in dark fermentation were acetate and butyrate, most of which can be consumed in co-cultivation. When sweet potato starch wastewater was used as the substrate, the highest COD, TN and TP removal and energy conversion efficiencies reached 80.5%, 88.7%, 80.1% and 34.2%, which were 176%, 178%, 200% and 119% higher than that of the control group (dark fermentation), respectively. This research provided a novel approach and achieved efficient simultaneous energy recovery and nutrients removal from starch wastewater by the co-culture system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of pentachlorophenol and chemical oxygen demand mass concentrations in influent on operational behaviors of upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Shen, Dong-Sheng; He, Ruo; Liu, Xin-Wen; Long, Yan

2006-08-25

Upflow anaerobic sludge blanket (UASB) reactor that was seeded with anaerobic sludge acclimated to chlorophenols was used to investigate the feasibility of anaerobic biotreatment of synthetic wastewater containing pentachlorophenol (PCP) with additional sucrose as carbon source. Two sets of UASB reactors were operated at one time. But the seeded sludge for the two reactors was different and Reactor I was seeded with the sludge that was acclimated to PCP completely for half a year, and Reactor II was seeded with the mixed sludge that was acclimated for half a year to PCP, 4-CP, 3-CP or 2-CP, respectively. The degradation of PCP and the operation fee treating the wastewater are affected by the concentration of MEDS (microorganism easily degradable substrate). So the confirmation of the suitable ratio of [COD] and [PCP] was the key factor of treating the wastewater containing PCP economically and efficiently. During the experiment, the synthetic wastewater with 180.0 mg L(-1) PCP and 1250-10000 mg L(-1) COD could be treated steadily in the experimental Reactor I. The removal efficiency of PCP was more than 99.5% and the removal efficiency of COD was up to 90%. [PCP] (concentration of PCP) in effluent was less than 0.5 mg L(-1). [PCP] in influent could affect proper [COD] (concentration of COD) range in influent that was required for maintenance of steady running of the experimental reactor with a hydraulic retention time (HRT) from 20 to 22 h. [PCP] in influent would directly affect the necessary [COD] in influent when the UASB reactor ran normally and treated the wastewater containing PCP. When [PCP] was 100.4, 151.6 and 180.8 mg L(-1) in influent, respectively, [COD] in influent had to be controlled about 1250-7500, 2500-5000 and 5000 mg L(-1) to maintain the UASB reactor steady running normally and contemporarily ensure that [COD] and [PCP] in effluent were less than 300 and 0.5 mg L(-1), respectively. With the increase of [PCP] in influent, the range of variation of [COD] in influent endured by the UASB reactor was decreasing. The ratios of [COD] and [PCP] in influent could affect removal efficiency of PCP and COD, the concentration of total volatile fatty acids (VFA) in effluent, biogas quantity and methane content in biogas. [PCP] in influent was linearly or semi-logarithmically correlated to [COD] in effluent when [COD] in influent was 5750+/-250 mg L(-1), and so was the relationship between [COD] in influent and [PCP] in effluent when [PCP] in influent was 100.4 or 151.6 mg L(-1), less than the maximum permissible [PCP]. The sources of seeded sludge, the way of sludge acclimation and the characteristics of anaerobic sludge could all affect the UASB reactor capacity treating PCP. When [PCP] were less than 180.8 mg L(-1) for Reactor I and 151.6 mg L(-1) for Reactor II, the variation of [PCP] in influent had little effect on the UASB reactor volume gas production rate and substrate gas production rate. And [VFA] and pH value in effluent were affected a little. Volume biogas production rate and substrate biogas production rate of the UASB reactor were only affected by [COD] and loading rate in influent. But when [PCP] was more than 151.6 mg L(-1) for Reactor II, the biogas production fell quickly and was over 3 days later. [VFA] in effluent from Reactor II increased up to 2198.1 mg L(-1) quickly and the pH value fell to less than 7. Reactor II could not run normally. The component of VFA accumulated quickly was mainly acetate (above 50%). With [PCP] increased from 7.9 to 180.8 mg L(-1) gradually in influent, the methane content in biogas from Reactor II decreased from 70% to 60%, but the reactor could still run normally. Then as for Reactor II, the content of methane have fallen from 75% to 45% or so quickly. And Reactor II could not run steadily. So the conclusion could be drown that too high [PCP] in influent for UASB reactor mainly inhibited the activity of methane-producing bacteria cultures utilizing the acetate.

Soft drink wastewater treatment by electrocoagulation-electrooxidation processes.

PubMed

Linares Hernández, Ivonne; Barrera Díaz, Carlos; Valdés Cerecero, Mario; Almazán Sánchez, Perla Tatiana; Castañeda Juárez, Monserrat; Lugo Lugo, Violeta

2017-02-01

The aim of this work was to implement a coupled system, a monopolar Electrocoagulation (EC)-Electrooxidation (EO) processes, for the treatment of soft drink wastewater. For the EC test, Cu-Cu, anode-cathode were used at current densities of 17, 51 and 68 mA cm -2 . Only 37.67% of chemical oxygen demand (COD) and 27% of total organic carbon (TOC) were removed at 20 min with an optimum pH of 8, this low efficiency can be associated with the high concentration of inorganic ions which inhibit the oxidation of organic matter due to their complexation with copper ions. Later EO treatment was performed with boron-doped diamond-Cu electrodes and a current density of 30 Am -2 . The coupled EC-EO system was efficient to reduce organic pollutants from initial values of 1875 mg L -1 TOC and 4300 mg L -1 COD, the removal efficiencies were 75% and 85%, respectively. Electric energy consumption to degrade a kilogram of a pollutant in the soft drink wastewater using EC was 3.19 kWh kg -1 TOC and 6.66 kWh kg -1 COD. It was concluded that the coupled system EC-EO was effective for the soft drink wastewater treatment, reducing operating costs and residence time, and allowing its reuse in indirect contact with humans, thus contributing to the sustainable reuse as an effluent of industrial wastewater.

The effect of different surface materials on runoff quality in permeable pavement systems.

PubMed

Li, Haiyan; Li, Zhifei; Zhang, Xiaoran; Li, Zhuorong; Liu, Dongqing; Li, Tanghu; Zhang, Ziyang

2017-09-01

To investigate the effect of different permeable pavement surface materials on the removal of pollutants from urban storm-runoff, six commonly surface materials (porous asphalt, porous concrete, cement brick, ceramic brick, sand base brick, and shale brick) were selected in this study and the research was carried out by column experiments. Except the concentrations of total suspended solids (TSS), chemical oxygen demand (COD), ammonia nitrogen (NH 4 -N), nitrate nitrogen (NO 3 -N), total nitrogen (TN), and total phosphorus (TP) in the influent and effluent that were measured, the removal mechanism of pollutants was discussed further. The results indicate that the surface materials influence the removal efficiency of pollutants greatly and have different effects on certain pollutant. Furthermore, the physical interception and adsorption would be the main mechanism for the removal of pollutants from runoff. For example, for all surface materials, the average removal efficiency of TSS is nearly about 90.0% because of physical interception. Due to the amount of iron oxide, the removal efficiency of COD, NO 3 -N, and TN of shale brick was 88.2, 35.1, and 17.5%, respectively. NH 4 -N and TN can be easily removed by porous asphalt due to the high content of organic matter. By lacking of useful adsorption sites, all the surface materials had little effect on the removal of TP from runoff. This research could offer useful guidelines for the better design of permeable pavement system and promote the insight into the removal mechanism of pollutants in permeable pavement system. Graphical abstract Different types of materials for the different types of pollutants in the runoff purification capacity were significantly different, overall, shale brick and porous asphalt Shale bricks and porous asphalt have a better purification effect according to the six kinds of materials.

Performance evaluation of a large sewage treatment plant in Brazil, consisting of an upflow anaerobic sludge blanket reactor followed by activated sludge.

PubMed

Saliba, Pollyane Diniz; von Sperling, Marcos

2017-10-01

The objective of this study was to evaluate the behaviour of a system comprising an upflow anaerobic sludge blanket reactor followed by activated sludge to treat domestic sewage. The Betim Central sewage treatment plant, Brazil, was designed to treat a mean influent flow of 514 L/s. The study consisted of statistical treatment of monitoring data from the treatment plant covering a period of 4 years. This work presents the concentrations and removal efficiencies of the main constituents in each stage of the treatment process, and a mass balance of chemical oxygen demand (COD) and nitrogen. The results highlight the good overall performance of the system, with high mean removal efficiencies: BOD (biochemical oxygen demand) (94%), COD (91%), ammonia (72%) and total suspended solids (92%). As expected, this system was not effective for the removal of nutrients, since it was not designed for this purpose. The removal of Escherichia coli (99.83%) was higher than expected. There was no apparent influence of operational and design parameters on the effluent quality in terms of organic matter removal, with the exceptions of the BOD load upstream of the aeration tank and the sludge age in the unit. Results suggest that this system is well suited for the treatment of domestic sewage.

Behaviour of molecular weight distribution for the liquid fraction of pig slurry treated by anaerobic digestion.

PubMed

Rodríguez, D C; Belmonte, M; Peñuela, G; Campos, J L; Vidal, G

2011-01-01

Pig slurry was treated in an upflow anaerobic sludge blanket (UASB) reactor. To maintain a stable operation, the organic loading rate (OLR) applied to the system was increased stepwise by decreasing the dilution ratio of the pig slurry. Finally, during the last operational stage, no dilution was applied to the influent. The reactor maintained a soluble chemical oxygen demand (CODs) removal efficiency of 82% when OLRs lower than 1.73 g CODs l(-1) d(-1) were applied, although its efficiency fell to 55% when operated at 2.48 g CODs l(-1) d(-1). System performance was not affected by the presence of free ammonia (concentrations up to 375 mg NH3 l(-1)). The distribution of the different molecular weight fractions changed significantly during anaerobic digestion. Proteins contained in the fractions higher than 10,000 Daltons are less degraded than those belonging to the lower fractions. An important percentage of both COD and BOD5 in the effluent were observed in the lowest fraction, probably caused by the presence of volatile fatty acids (VFA).

Roughness and temperature effects on the filter media of a trickling filter for nitrification.

PubMed

Kishimoto, Naoyuki; Ohara, Tetsuya; Hinobayashi, Jouji; Hashimoto, Tsutomu

2014-01-01

The performance of trickling filters using two types of plastic media with the same material, the same shape and different roughness was evaluated during a temperature-decreasing period to understand the roughness and temperature effects on the filter media. Real restaurant wastewater was used for the experiments. The chemical oxygen demand (COD) removal and nitrification performance of plastic media with a rough surface (LT-15) was superior to that with a smooth surface (KT-15). Because the biomass of microorganisms attached on the LT-15 was twice that attached on the KT-15, the larger biomass attached on the LT-15 was thought to be responsible for the higher performance. During the operation, the COD loading and water temperature varied in the range from 0.37 to 1.9 kg m(-3) d(-1) and 17.0--10.0 degrees C, respectively. However, the COD removal performance was not dependent on the COD loading or water temperature. On the contrary, the COD loading and the water temperature influenced the nitrification performance. Although a nitrification efficiency of 100% was recorded at a COD loading of 0.37 kg m(-3) d(-1), it deteriorated to 17-28% at higher COD loading. Moreover, a decline in the water temperature decreased the nitrification performance. The temperature-activity coefficient for nitrification was estimated to be 1.096. Based on this value, it was inferred that the COD loading should be set at less than 0.20 kg m(-3) d(-1) for the complete nitrification of the restaurant wastewater in winter, when the water temperature usually drops to around 10 degrees C.

Anaerobic membrane bioreactor for the treatment of leachates from Jebel Chakir discharge in Tunisia.

PubMed

Zayen, Amal; Mnif, Sami; Aloui, Fathi; Fki, Firas; Loukil, Slim; Bouaziz, Mohamed; Sayadi, Sami

2010-05-15

Landfill leachate (LFL) collected from the controlled discharge of Jebel Chakir in Tunisia was treated without any physical or chemical pretreatment in an anaerobic membrane bioreactor (AnMBR). The organic loading rate (OLR) in the AnMBR was gradually increased from 1 g COD l(-1)d(-1) to an average of 6.27 g COD l(-1)d(-1). At the highest OLR, the biogas production was more than 3 volumes of biogas per volume of the bioreactor. The volatile suspended solids (VSSs) reached a value of approximately 3 g l(-1) in the bioreactor. At stable conditions, the treatment efficiency was high with an average COD reduction of 90% and biogas yield of 0.46 l biogas per g COD removed. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Two-stage conversion of crude glycerol to energy using dark fermentation linked with microbial fuel cell or microbial electrolysis cell.

PubMed

Chookaew, Teera; Prasertsan, Poonsuk; Ren, Zhiyong Jason

2014-03-25

Crude glycerol is a main byproduct of the biodiesel industry, and the beneficial use of waste glycerol has been a major challenge. This study characterises the conversion of crude glycerol into bioenergy such as H2 and electricity using a two-stage process linking dark fermentation with a microbial fuel cell (MFC) or microbial electrolysis cell (MEC). The results showed that fermentation achieved a maximum H2 rate of 332 mL/L and a yield of 0.55 mol H2/mol glycerol, accompanied by 20% of organic removal. Fed with the raw fermentation products with an initial COD of 7610 mg/L, a two-chamber MFC produced 92 mW/m(2) in power density and removed 50% of COD. The Columbic efficiency was 14%. When fed with 50% diluted fermentation product, a similar power output (90m W/m(2)) and COD removal (49%) were obtained, but the CE doubled to 27%. Similar substrates were used to produce H2 in two-chamber MECs, and the diluted influent had a higher performance, with the highest yield at 106 mL H2/g COD and a CE of 24%. These results demonstrate that dark fermentation linked with MFC/MEC can be a feasible option for conversion of waste glycerol into bioenergy. Copyright © 2013 Elsevier B.V. All rights reserved.

TREATMENT OF LANDFILL LEACHATE BY COUPLING COAGULATION-FLOCCULATION OR OZONATION TO GRANULAR ACTIVATED CARBON ADSORPTION.

PubMed

Oloibiri, Violet; Ufomba, Innocent; Chys, Michael; Audenaert, Wim; Demeestere, Kristof; Van Hulle, Stijn W H

2015-01-01

A major concern for landfilling facilities is the treatment of their leachate. To optimize organic matter removal from this leachate, the combination of two or more techniques is preferred in order to meet stringent effluent standards. In our study, coagulation-flocculation and ozonation are compared as pre- treatment steps for stabilized landfill leachate prior to granular activated carbon (GAC) adsorption. The efficiency of the pre treatment techniques is evaluated using COD and UVA254 measurements. For coagulation- flocculation, different chemicals are compared and optimal dosages are determined. After this, iron (III) chloride is selected for subsequent adsorption studies due to its high percentage of COD and UVA254 removal and good sludge settle-ability. Our finding show that ozonation as a single treatment is effective in reducing COD in landfill leachate by 66% compared to coagulation flocculation (33%). Meanwhile, coagulation performs better in UVA254 reduction than ozonation. Subsequent GAC adsorption of ozonated effluent, coagulated effluent and untreated leachate resulted in 77%, 53% and 8% total COD removal respectively (after 6 bed volumes). The effect of the pre-treatment techniques on GAC adsorption properties is evaluated experimentally and mathematically using Thomas and Yoon-Nelson models. Mathematical modelling of the experimental GAC adsorption data shows that ozonation increases the adsorption capacity and break through time with a factor of 2.5 compared to coagulation-flocculation.

Quantitative characterization of organic diffusion using an analytical diffusion-reaction model and its application to assessing BOD removal when treating municipal wastewater in a plug flow reactor.

PubMed

Fan, Chihhao; Kao, Chen-Fei; Liu, Yu-Hsi

2017-09-15

The present study aimed to derive an analytical formula to quantify the diffusion of organic contaminant in a biofilm. The experiments were conducted to investigate the BOD degradation under the conditions of influent COD concentration from 50 to 300 mg/L, COD:N:P ratios of 100:5:1 and 100:15:3, with and without auxiliary aeration. The BOD removal rate was around 73% for non-aerated influent COD of 50 mg/L with 1-h hydraulic retention time. The BOD removal rate increased as the influent loading and hydraulic retention time increased while the influent COD was no more than 150 mg/L. Without aeration, the removal rate dropped significantly when influent COD increased to the range no less than 200 mg/L, due to the fact that the BOD diffusive flux driven by the biomass uptake was not further enhanced by higher ambient organic loading. The diffusion coefficient was calculated to be 1.12 × 10 -6  m 2 /d with influent COD of 50 mg/L at COD:N:P ratio of 100:5:1 and 1 h hydraulic retention time and aeration, and the coefficient increased to 3.35 × 10 -6  m 2 /d as the influent COD concentration increased to 300 mg/L. The diffusion coefficient decreased to 4.09 × 10 -7  m 2 /d as the retention time increased to 3 h. The overall diffusion coefficients showed an increasing trend as the influent organic loading increased. The difference in diffusion coefficients between 1 and 2 h was apparently greater than that between 2 and 3 h, indicating a smaller overall diffusive flux due to a longer retention time. Further analysis revealed that BOD diffusion activity exhibited a declining trend as the wastewater travelled through the system. An analytical diffusion-reaction model was developed to characterize the diffusion behaviour, and applied to estimating the treatment efficiency for real domestic sewage. The result showed that the estimated effluent BOD concentrations were quite comparable to those from experimental measurements. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics and efficiency of ozone for treatment of landfill leachate including the effect of previous microbiological treatment.

PubMed

Lovato, María; Buffelli, José Real; Abrile, Mariana; Martín, Carlos

2018-03-19

The application of conventional physicochemical and microbiological techniques for the removal of organic pollutants has limitations for its utilization on wastewaters as landfill leachates because of their high concentration of not easily biodegradable organic compounds. The use of ozone-based technologies is an alternative and complementary treatment for this type of wastewaters. This paper reports the study of the degradation of landfill leachates from different stages of a treatment plant using ozone and ozone + UV. The experimental work included the determination of the temporal evolution of COD, TOC, UV254, and color. Along the experimental runs, the instantaneous off-gas ozone concentration was measured. The reaction kinetics follows a global second order expression with respect to COD and ozone concentrations. A kinetic model which takes into account the gas liquid mass transfer coupled with the chemical reaction was developed, and the corresponding parameters of the reacting system were determined. The mathematical model is able to appropriately simulate COD and ozone concentrations but exhibiting limitations when varying the leachate type. The potential application of ozone was verified, although the estimated efficiencies for COD removal and ozone consumption as well as the effect of UV radiation show variations on their trends. In this sense, it is interesting to note that the relative ozone yield has significant oscillations as the reaction proceeds. Finally, the set of experimental results demonstrates the crucial importance of the selection of process conditions to improve ozone efficiencies. This approach should consider variations in the ozone supply in order to minimize losses as well as the design of exhaustion methods as multiple stage reactors using chemical engineering design tools.

Performance of enhanced biological SBR process for aniline treatment by mycelial pellet as biomass carrier.

PubMed

Zhang, Si; Li, Ang; Cui, Di; Yang, Jixian; Ma, Fang

2011-03-01

Mycelial pellet of Aspergillus niger Y3 was used as a biomass carrier to immobilize the aniline-degrading bacterium, Acinetobacter calcoaceticus JH-9 and the mix culture of the COD rapid degradation bacteria. In order to investigate its removal effect on aniline and COD, the combined mycelial pellets were applied in the SBR. Comparison of the performances was conducted between another SBR inoculated with sole strain JH-9 and the above SBR. The results showed that the stable degradations of aniline and COD were observed in both reactors. In the SBR with combined mycelial pellet, the biological removal efficiency was about 0.9 mg aniline/(L·d). It was much higher than that in the activated sludge reactor. Meanwhile, the performances of the sedimentation velocity, liquid-solid phase separation and the effluent quality were better in the SBR. According to SEM images and PCR-DGGE analysis, the species immobilized on the biomass carrier were more predominant in this system. Copyright © 2010 Elsevier Ltd. All rights reserved.

Potential of tin (IV) chloride for treatment in Alor Pongsu as stabilized landfill leachate

NASA Astrophysics Data System (ADS)

Zainal, Sharifah Farah Fariza Syed; Aziz, Hamidi Abdul

2017-10-01

Leachate production from landfilling contributes crucial pollutants to the environment. This study examined the potential of tin (IV) chloride as coagulant that involved charge neutralization and sweep flocculation mechanisms. The negative charge of leachate is neutralized by adding tin (IV) chloride as cationic coagulant which resulted precipitation and swept most of the colloids and dissolved solids that entrapped in the settling as hydrous oxide floc. Parameters such as suspended solid (SS) content, color, and chemical oxygen demand (COD) were analyzed using standard jar test procedures. The best condition was observed at pH 8, with removal efficiencies of 75.99 %, 99.29 % and 98.36 % for COD, SS, and color, respectively. At optimum dosage, tin (IV) chloride successfully removed 98.40 % for color, 99.54 % for SS and 71.53 % for COD. These results indicated the satisfactory performance of tin (IV) chloride. Hence, tin (IV) chloride is a potential coagulant for the treatment of Alor Pongsu Landfill leachate.

Effects of organic loading rates on reactor performance and microbial community changes during thermophilic aerobic digestion process of high-strength food wastewater.

PubMed

Jang, Hyun Min; Lee, Jae Won; Ha, Jeong Hyub; Park, Jong Moon

2013-11-01

To evaluate the applicability of single-stage thermophilic aerobic digestion (TAD) process treating high-strength food wastewater (FWW), TAD process was operated at four organic loading rates (OLRs) from 9.2 to 37.2 kg COD/m(3)d. The effects of OLRs on microbial community changes were also examined. The highest volumetric removal rate (13.3 kg COD/m(3)d) and the highest thermo-stable protease activity (0.95 unit/mL) were detected at OLR=18.6 kg COD/m(3)d. Denaturing gradient gel electrophoresis (DGGE) profiles and quantitative PCR (qPCR) results showed significant microbial community shifts in response to changes in OLR. In particular, DGGE and phylogenetic analysis demonstrate that the presence of Bacillus sp. (phylum of Firmicutes) was strongly correlated with efficient removal of organic particulates from high-strength food wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Anaerobic co-digestion of acetate-rich with lignin-rich wastewater and the effect of hydrotalcite addition.

PubMed

Rodriguez-Chiang, Lourdes; Llorca, Jordi; Dahl, Olli

2016-10-01

The methane potential and biodegradability of different ratios of acetate and lignin-rich effluents from a neutral sulfite semi-chemical (NSSC) pulp mill were investigated. Results showed ultimate methane yields up to 333±5mLCH4/gCOD when only acetate-rich substrate was added and subsequently lower methane potentials of 192±4mLCH4/gCOD when the lignin fraction was increased. The presence of lignin showed a linear decay in methane production, resulting in a 41% decrease in methane when the lignin-rich feed had a 30% increase. A negative linear correlation between lignin content and biodegradability was also observed. Furthermore, the effect of hydrotalcite (HT) addition was evaluated and showed increase in methane potential of up to 8%, a faster production rate and higher soluble lignin removal (7-12% higher). Chemical oxygen demand (COD) removal efficiencies between 64 and 83% were obtained for all samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance and fouling characteristics of a submerged anaerobic membrane bioreactor for kraft evaporator condensate treatment.

PubMed

Xie, K; Lin, H J; Mahendran, B; Bagley, D M; Leung, K T; Liss, S N; Liao, B Q

2010-04-14

Submerged anaerobic membrane bioreactor (SAnMBR) technology was studied for kraft evaporator condensate treatment at 37 +/- 1 degrees C over a period of 9 months. Under tested organic loading rates of 1-24 kg COD/m3/day, a chemical oxygen demand (COD) removal efficiency of 93-99% was achieved with a methane production rate of 0.35 +/- 0.05 L methane/g COD removed and a methane content of 80-90% in produced biogas. Bubbling of recycled biogas was effective for in-situ membrane cleaning, depending on the biogas sparging rate used. The membrane critical flux increased and the membrane fouling rate decreased with an increase in the biogas sparging rate. The scanning electron microscopy images showed membrane pore clogging was not significant and sludge cake formation on the membrane surface was the dominant mechanism of membrane fouling. The results suggest that the SAnMBR is a promising technology for energy recovery from kraft evaporator condensate.

Start-up and operation strategies on the liquefied food waste anaerobic digestion and a full-scale case application.

PubMed

Meng, Ying; Shen, Fei; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Chufo, Akiber; Jaffar, Muhammad; Li, Xiujin

2014-11-01

Batch anaerobic digestion was employed to investigate the efficient start-up strategies for the liquefied food waste, and sequencing batch digestion was also performed to determine maximum influent organic loading rate (OLR) for efficient and stable operation. The results indicated that the start-up could be well improved using appropriate wastewater organic load and food-to-microorganism ratios (F/M). When digestion was initialized at low chemical oxygen demand (COD) concentration of 20.0 gCOD L(-1), the start-up would go well using lower F/M ratio of 0.5-0.7. The OLR 7.0 gCOD L(-1) day(-1) was recommended for operating the ASBR digestion, in which the COD conversion of 96.7 ± 0.53% and biomethane yield of 3.5 ± 0.2 L gCOD(-1) were achieved, respectively. The instability would occur when OLR was higher than 7.0 gCOD L(-1) day(-1), and this instability was not recoverable. Lipid was suggested to be removed before anaerobic digestion. The anaerobic digestion process in engineering project ran well, and good performance was achieved when the start-up and operational strategies from laboratory study were applied. For case application, stable digestion performance was achieved in a digester (850 m(3) volume) with biogas production of 1.0-3.8 m(3) m(-3) day(-1).

Mainstream upflow nitritation-anammox system with hybrid anaerobic pretreatment: Long-term performance and microbial community dynamics.

PubMed

Li, Xiaojin; Sun, Shan; Yuan, Heyang; Badgley, Brian D; He, Zhen

2017-11-15

Mainstream nitritation-anammox is of strong interest to energy- and resource-efficient domestic wastewater treatment. However, there lack in-depth studies of pretreatment, tests of actual wastewater, and examination of long-term performance. Herein, an upflow nitritation-anammox granular reactor has been investigated to treat primary effluent with a hybrid anaerobic reactor (HAR) as pretreatment for more than 300 days. This system achieved 92% of COD removal, 75% of which was accomplished by the HAR, and had an average final effluent COD concentration of 22 mg L -1 . More than 90% of ammonium was removed in the nitritation-anammox reactor, achieving a nitrogen removal rate of 81.0 g N m -3  d -1 in the last stage. The accumulation of sulfate-reducing bacteria in the HAR evidenced the effect of sulfate on COD removal and subsequent nitrogen removal. Anammox bacteria (predominantly Ca. Jettenia asiatica) accounted for up to 40.2% of total granular communities, but their abundance decreased over time in the suspended communities. The dynamics of major metabolisms and functional genes involved in nitrogen conversion were predicted by PICRUSt based on the taxonomic data, providing more insights into the functions of the microbial communities. These results have demonstrated the effectiveness and importance of anaerobic pretreatment to successful mainstream nitritation-anammox. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multiple response optimization for high efficiency energy saving treatment of rhodamine B wastewater in a three-dimensional electrochemical reactor.

PubMed

Ji, Jing; Liu, Yang; Yang, Xue-Yuan; Xu, Juan; Li, Xiu-Yan

2018-07-15

The removal of high-concentration rhodamine B (RhB) wastewater was investigated in a three-dimensional electrochemical reactor (3DER) packed with granular activated carbon (GAC) particle electrodes. Response surface methodology (RSM) coupled with grey relational analysis (GRA) was used to evaluate the effects of voltage, initial pH, aeration rate and NaCl dosage on RhB removal and energy consumption of the 3DER. The optimal conditions were determined as voltage 7.25 V, pH 5.99, aeration rate 151.13 mL/min, and NaCl concentration 0.11 mol/L. After 30 min electrolysis, COD removal rate could arrive at 60.13% with an extremely low energy consumption of 6.22 kWh/kg COD. The voltage and NaCl were demonstrated to be the most significant factors affecting the COD removal and energy consumption of 3DER. The intermediates generated during the treatment process were identified and the possible degradation pathway of RhB was proposed. It is worth noting that 3DER also showed an excellent performance in total nitrogen (TN) removal under the optimal condition. The activated chlorine generated from chloride had great contributions to eliminate carbon and nitrogen of RhB wastewater. The treatment effluent had a good biodegradability, which was suitable for subsequent biological treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Organic compounds removal and toxicity reduction of landfill leachate by commercial bakers' yeast and conventional bacteria based membrane bioreactor integrated with nanofiltration.

PubMed

Reis, Beatriz Gasparini; Silveira, Amanda Lemes; Tostes Teixeira, Luiza Procópio; Okuma, Adriana Akemi; Lange, Liséte Celina; Amaral, Miriam Cristina Santos

2017-12-01

This study aimed to compare the performance of a commercial bakers' yeast (MBRy) and conventional bacteria (MBRb) based membrane bioreactor integrated with nanofiltration (NF) in the removal of landfill leachate toxicity. Performances were evaluated using physicochemical analyses, toxicity tests and identification of organic compounds. The MBR b and MBR y were operated with a hydraulic retention time (HRT) of 48h and solids retention time (SRT) of 60 d. The MBR y demonstrated better removal efficiencies for COD (69±7%), color (54±11%) and ammoniacal nitrogen (34±7%) compared to MBR b , which showed removal efficiencies of 27±5%, 33±4% and 27±7%, for COD, color and ammoniacal nitrogen. Although the MBR y seems to be the configuration that presented the highest efficiency; it generated toxic permeate whose toxicity cannot be explained by physicochemical results. The identification of compounds shows that there is a wide range of compounds in the landfill leachate in addition to others that are produced in the biological treatment steps. The NF plays a crucial role in the polishing of the final effluents by the either complete or partial retention of compounds, that attribute toxicity to the leachate, and inorganic contaminants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of lab-scale horizontal subsurface flow constructed wetlands treating industrial cork boiling wastewater.

PubMed

Gomes, Arlindo C; Silva, Lúcia; Albuquerque, António; Simões, Rogério; Stefanakis, Alexandros I

2018-09-01

The feasibility and treatment efficiency of horizontal subsurface flow constructed wetlands (HSFCW) was assessed for the first time for cork boiling wastewater (CBW) through laboratory experiments. CBW is known for its high content of phenolic compounds, complex composition of biorecalcitrant and toxic nature. Two lab-scale units, one planted with Phragmites australis (CWP) and one unplanted (CWC), were used to evaluate the removals of COD, BOD, total phenolic compounds (TPh) and decolourization over a 2.5-years monitoring period under Mediterranean climatic conditions. Seven organic and hydraulic loading rates ranging from 2.6 to 11.5 g COD/m 2 /d and 5.7-9.1 L/m 2 /d were tested under average hydraulic retention time (HRT) of 5 ± 1 days required due to the CWB limited biodegradability (i.e., BOD 5 /COD of 0.19). Average removals of the CWP exceeded those of the CWC and reached 74.6%, 91.7% and 69.1% for COD, BOD 5 and TPh, respectively, with respective mass removals rates up to 7.0, 1.7 and 0.5 (in g/m 2 /d). Decolourization was limited to 35%, since it mainly depends on physical processes rather than biodegradation. CBW concentration of nine phenolic compounds ranged from 1.2 to 38.4 mg/L (for the syringic and ellagic acids, respectively) in the raw CBW, with respective removals in the CWP unit ranging from 41.8 to 76.3%, higher than those in the control unit. Despite CBW high concentration of TPhs (average of 116.3 mg/L), the HSFCW reached organic load removals higher than those of conventional biological treatment methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electrocoagulation efficiency of the tannery effluent treatment using aluminium electrodes.

PubMed

Espinoza-Quiñones, Fernando R; Fornari, Marilda M T; Módenes, Aparecido N; Palácio, Soraya M; Trigueros, Daniela E G; Borba, Fernando H; Kroumov, Alexander D

2009-01-01

An electro-coagulation laboratory scale system using aluminium plates electrodes was studied for the removal of organic and inorganic pollutants as a by-product from leather finishing industrial process. A fractional factorial 2(3) experimental design was applied in order to obtain optimal values of the system state variables. The electro-coagulation (EC) process efficiency was based on the chemical oxygen demand (COD), turbidity, total suspended solid, total fixed solid, total volatile solid, and chemical element concentration values. Analysis of variance (ANOVA) for final pH, total fixed solid (TFS), turbidity and Ca concentration have confirmed the predicted models by the experimental design within a 95% confidence level. The reactor working conditions close to real effluent pH (7.6) and electrolysis time in the range 30-45 min were enough to achieve the cost effective reduction factors of organic and inorganic pollutants' concentrations. An appreciable improvement in COD removal efficiency was obtained for electro-coagulation treatment. Finally, the technical-economical analysis results have clearly shown that the electro-coagulation method is very promising for industrial application.

Unravelling the active microbial community in a thermophilic anaerobic digester-microbial electrolysis cell coupled system under different conditions.

PubMed

Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

2017-03-01

Thermophilic anaerobic digestion (AD) of pig slurry coupled to a microbial electrolysis cell (MEC) with a recirculation loop was studied at lab-scale as a strategy to increase AD stability when submitted to organic and nitrogen overloads. The system performance was studied, with the recirculation loop both connected and disconnected, in terms of AD methane production, chemical oxygen demand removal (COD) and volatile fatty acid (VFA) concentrations. Furthermore, the microbial population was quantitatively and qualitatively assessed through DNA and RNA-based qPCR and high throughput sequencing (MiSeq), respectively to identify the RNA-based active microbial populations from the total DNA-based microbial community composition both in the AD and MEC reactors under different operational conditions. Suppression of the recirculation loop reduced the AD COD removal efficiency (from 40% to 22%) and the methane production (from 0.32 to 0.03 m 3  m -3  d -1 ). Restoring the recirculation loop led to a methane production of 0.55 m 3  m -3  d -1 concomitant with maximum MEC COD and ammonium removal efficiencies of 29% and 34%, respectively. Regarding microbial analysis, the composition of the AD and MEC anode populations differed from really active microorganisms. Desulfuromonadaceae was revealed as the most active family in the MEC (18%-19% of the RNA relative abundance), while hydrogenotrophic methanogens (Methanobacteriaceae) dominated the AD biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of textile wastewater by a hybrid electrocoagulation/nanofiltration process.

PubMed

Aouni, Anissa; Fersi, Cheïma; Ben Sik Ali, Mourad; Dhahbi, Mahmoud

2009-09-15

Untreated effluents from textile industries are usually highly coloured and contain a considerable amount of contaminants and pollutants. Stringent environmental regulation for the control of textile effluents is enforced in several countries. Previous studies showed that many techniques have been used for the treatment of textile wastewater, such as adsorption, biological treatment, oxidation, coagulation and/or flocculation, among them coagulation is one of the most commonly used techniques. Electrocoagulation is a process consisting in creating metallic hydroxide flocks within the wastewater by the electrodissolution of soluble anodes, usually made of iron or aluminium. This method has been practiced for most of the 20th century with limited success. In recent years, however, it started to regain importance with the progress of the electrochemical processes and the increase in environmental restrictions in effluent wastewater. This paper examines the use of electrocoagulation treatment process followed by nanofiltration process of a textile effluent sample. The electrocoagulation process was studied under several conditions such as various current densities and effect of experimental tense. Efficiencies of COD and turbidity reductions and colour removal were studied for each experiment. The electrochemical treatment was indented primarily to remove colour and COD of wastewater while nanofiltration was used to further improve the removal efficiency of the colour, COD, conductivity, alkalinity and total dissolved solids (TDS). The experimental results, throughout the present study, have indicated that electrocoagulation treatment followed by nanofiltration processes were very effective and were capable of elevating quality of the treated textile wastewater effluent.

Effects of sludge recirculation rate and mixing time on performance of a prototype single-stage anaerobic digester for conversion of food wastes to biogas and energy recovery.

PubMed

Ratanatamskul, Chavalit; Saleart, Tawinan

2016-04-01

Food wastes have been recognized as the largest waste stream and accounts for 39.25 % of total municipal solid waste in Thailand. Chulalongkorn University has participated in the program of in situ energy recovery from food wastes under the Ministry of Energy (MOE), Thailand. This research aims to develop a prototype single-stage anaerobic digestion system for biogas production and energy recovery from food wastes inside Chulalongkorn University. Here, the effects of sludge recirculation rate and mixing time were investigated as the main key parameters for the system design and operation. From the results obtained in this study, it was found that the sludge recirculation rate of 100 % and the mixing time of 60 min per day were the most suitable design parameters to achieve high efficiencies in terms of chemical oxygen demand (COD), total solids (TS), and total volatile solid (TVS) removal and also biogas production by this prototype anaerobic digester. The obtained biogas production was found to be 0.71 m(3)/kg COD and the composition of methane was 61.6 %. Moreover, the efficiencies of COD removal were as high as 82.9 % and TVS removal could reach 83.9 % at the optimal condition. Therefore, the developed prototype single-stage anaerobic digester can be highly promising for university canteen application to recover energy from food wastes via biogas production.

Treatment of table olive washing water using trickling filters, constructed wetlands and electrooxidation.

PubMed

Tatoulis, Triantafyllos; Stefanakis, Alexandros; Frontistis, Zacharias; Akratos, Christos S; Tekerlekopoulou, Athanasia G; Mantzavinos, Dionissios; Vayenas, Dimitrios V

2017-01-01

The production of table olives is a significant economic activity in Mediterranean countries. Table olive processing generates large volumes of rinsing water that are characterized by high organic matter and phenol contents. Due to these characteristics, a combination of more than one technology is imperative to ensure efficient treatment with low operational cost. Previously, biological filters were combined with electrooxidation to treat table olive washing water. Although this combination was successful in reducing pollutant loads, its cost could be further reduced. Constructed wetlands could be an eligible treatment method for integrated table olive washing water treatment as they have proved tolerant to high organic matter and phenol loads. Two pilot-scale horizontal subsurface constructed wetlands, one planted and one unplanted, were combined with a biological filter and electrooxidation over a boron-doped diamond anode to treat table olive washing water. In the biological filter inlet, chemical oxygen demand (COD) concentrations ranged from 5500 to 15,000 mg/L, while mean COD influent concentration in the constructed wetlands was 2800 mg/L. The wetlands proved to be an efficient intermediate treatment stage, since COD removal levels for the planted unit reached 99 % (mean 70 %), while the unplanted unit presented removal rates of around 65 %. Moreover, the concentration of phenols in the effluent was typically below 100 mg/L. The integrated trickling filter-constructed wetland-electrooxidation treatment system examined here could mineralize and decolorize table olive washing water and fully remove its phenolic content.

Comparison of photo-Fenton, O3/H2O2/UV and photocatalytic processes for the treatment of gray water.

PubMed

Hassanshahi, Nahid; Karimi-Jashni, Ayoub

2018-06-21

This research was carried out to compare and optimize the gray water treatment performance by the photo-Fenton, photocatalysis and ozone/H 2 O 2 /UV processes. Experimental design and optimization were carried out using Central Composite Design of Response Surface Methodology. The results of experiments showed that the most effective and influencing factors in photo-Fenton process were H 2 O 2 /Fe 2+ ratio, in ozone/H 2 O 2 /UV experiment were O 3 concentration, H 2 O 2 concentration, reaction time and pH and in photocatalytic process were TiO 2 concentration, pH and reaction time. The highest COD removal in photo-Fenton, ozone/H 2 O 2 /UV and photocatalytic process were 90%, 92% and 55%, respectively. The results were analyzed by design expert software and for all three processes second-order models were proposed to simulate the COD removal efficiency. In conclusion the ozone/H 2 O 2 /UV process is recommended for the treatment of gray water, since it was able to remove both COD and turbidity by 92% and 93%, respectively. Copyright © 2018 Elsevier Inc. All rights reserved.

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, ZhiPing, E-mail: liulqs@163.com; Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020; Wu, WenHui

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by themore » combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.« less

Simultaneous efficient removal of high-strength ammonia nitrogen and chemical oxygen demand from landfill leachate by using an extremely high ammonia nitrogen-resistant strain.

PubMed

Yu, Dahai; Yang, Jiyu; Fang, Xuexun; Ren, Hejun

2015-01-01

Bioaugmentation is a promising technology for pollutant elimination from stressed environments, and it would provide an efficient way to solve challenges in traditional biotreatment of wastewater with high strength of ammonia nitrogen (NH4(+)-N). A high NH4(+)-N-resistant bacteria strain, identified as Bacillus cereus (Jlu BC), was domesticated and isolated from the bacteria consortium in landfill leachate. Jlu BC could survive in 100 g/L NH4(+)-N environment, which indicated its extremely high NH4(+)-N tolerance than the stains found before. Jlu BC was employed in the bioaugmented system to remove high strength of NH4(+)-N from landfill leachate, and to increase the removal efficiency, response surface methodology (RSM) was used for optimizing bioaugmentation degradation conditions. At the optimum condition (initial pH 7.33, 4.14 days, initial chemical oxygen demand [COD] concentration [18,000 mg/L], 3.5 mL inoculated domesticated bacteria strain, 0.3 mg/mL phosphorus supplement, 30 °C, and 170 rpm), 94.74 ± 3.8% removal rate of NH4(+)-N was obtained, and the experiment data corresponded well with the predicted removal rate of the RSM models (95.50%). Furthermore, COD removal rate of 81.94 ± 1.4% was obtained simultaneously. The results presented are promising, and the screened strain would be of great practical importance in mature landfill leachate and other NH4(+)-N enrichment wastewater pollution control. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Reduction of selenite to elemental selenium nanoparticles by activated sludge.

PubMed

Jain, Rohan; Matassa, Silvio; Singh, Satyendra; van Hullebusch, Eric D; Esposito, Giovanni; Lens, Piet N L

2016-01-01

Total selenium removal by the activated sludge process, where selenite is reduced to colloidal elemental selenium nanoparticles (BioSeNPs) that remain entrapped in the activated sludge flocs, was studied. Total selenium removal efficiencies with glucose as electron donor (2.0 g chemical oxygen demand (COD) L(-1)) at neutral pH and 30 °C gave 2.9 and 6.8 times higher removal efficiencies as compared to the electron donors lactate and acetate, respectively. Total selenium removal efficiencies of 79 (±3) and 86 (±1) % were achieved in shake flasks and fed batch reactors, respectively, at dissolved oxygen (DO) concentrations above 4.0 mg L(-1) and 30 °C when fed with 172 mg L(-1) (1 mM) Na2SeO3 and 2.0 g L(-1) COD of glucose. Continuously operated reactors operating at neutral pH, 30 °C and a DO >3 mg L(-1) removed 33.98 and 36.65 mg of total selenium per gram of total suspended solids (TSS) at TSS concentrations of 1.3 and 3.0 g L(-1), respectively. However, selenite toxicity to the activated sludge led to failure of a continuously operating activated sludge reactor at the applied loading rates. This suggests that a higher hydraulic retention time (HRT) or different reactor configurations need to be applied for selenium-removing activated sludge processes. Graphical Abstract Scheme representing the possible mechanisms of selenite reduction at high and low DO levels in the activated sludge process.

Oil refinery wastewater treatment using coupled electrocoagulation and fixed film biological processes

NASA Astrophysics Data System (ADS)

Pérez, Laura S.; Rodriguez, Oscar M.; Reyna, Silvia; Sánchez-Salas, José Luis; Lozada, J. Daniel; Quiroz, Marco A.; Bandala, Erick R.

2016-02-01

Oil refinery wastewater was treated using a coupled treatment process including electrocoagulation (EC) and a fixed film aerobic bioreactor. Different variables were tested to identify the best conditions using this procedure. After EC, the effluent was treated in an aerobic biofilter. EC was capable to remove over 88% of the overall chemical oxygen demand (COD) in the wastewater under the best working conditions (6.5 V, 0.1 M NaCl, 4 electrodes without initial pH adjustment) with total petroleum hydrocarbon (TPH) removal slightly higher than 80%. Aluminum release from the electrodes to the wastewater was found an important factor for the EC efficiency and closely related with several operational factors. Application of EC allowed to increase the biodegradability of the sample from 0.015, rated as non-biodegradable, up to 0.5 widely considered as biodegradable. The effluent was further treated using an aerobic biofilter inoculated with a bacterial consortium including gram positive and gram negative strains and tested for COD and TPH removal from the EC treated effluent during 30 days. Cell count showed the typical bacteria growth starting at day three and increasing up to a maximum after eight days. After day eight, cell growth showed a plateau which agreed with the highest decrease on contaminant concentration. Final TPHs concentration was found about 600 mgL-1 after 30 days whereas COD concentration after biological treatment was as low as 933 mgL-1. The coupled EC-aerobic biofilter was capable to remove up to 98% of the total TPH amount and over 95% of the COD load in the oil refinery wastewater.

Performance of air-cathode stacked microbial fuel cells systems for wastewater treatment and electricity production.

PubMed

Estrada-Arriaga, Edson Baltazar; Guillen-Alonso, Yvonne; Morales-Morales, Cornelio; García-Sánchez, Liliana; Bahena-Bahena, Erick Obed; Guadarrama-Pérez, Oscar; Loyola-Morales, Félix

2017-07-01

Two different air-cathode stacked microbial fuel cell (MFC) configurations were evaluated under continuous flow during the treatment of municipal wastewater and electricity production at a hydraulic retention time (HRT) of 3, 1, and 0.5 d. Stacked MFC 1 was formed by 20 individual air-cathode MFC units. The second stacked MFC (stacked MFC 2) consisted of 40 air-cathode MFC units placed in a shared reactor. The maximum voltages produced at closed circuit (1,000 Ω) were 170 mV for stacked MFC 1 and 94 mV for stacked MFC 2. Different power densities in each MFC unit were obtained due to a potential drop phenomenon and to a change in chemical oxygen demand (COD) concentrations inside reactors. The maximum power densities from individual MFC units were up to 1,107 mW/m 2 for stacked MFC 1 and up to 472 mW/m 2 for stacked MFC 2. The maximum power densities in stacked MFC 1 and MFC 2 connected in series were 79 mW/m 2 and 4 mW/m 2 , respectively. Electricity generation and COD removal efficiencies were reduced when the HRT was decreased. High removal efficiencies of 84% of COD, 47% of total nitrogen, and 30% of total phosphorus were obtained during municipal wastewater treatment.

A submerged tubular ceramic membrane bioreactor for high strength wastewater treatment.

PubMed

Sun, D D; Zeng, J L; Tay, J H

2003-01-01

A 4 L submerged tubular ceramic membrane bioreactor (MBR) was applied in laboratory scale to treat 2,400 mg-COD/L high strength wastewater. A prolonged sludge retention time (SRT) of 200 day, in contrast to the conventional SRT of 5 to 15 days, was explored in this study, aiming to reduce substantially the amount of disposed sludge. The MBR system was operated for a period of 142 days in four runs, differentiated by specific oxygen utilization rate (SOUR) and hydraulic retention time (HRT). It was found that the MBR system produced more than 99% of suspended solid reduction. Mixed liquor suspended solids (MLSS) was found to be adversely proportional to HRT, and in general higher than the value from a conventional wastewater treatment plant. A chemical oxygen demand (COD) removal efficiency was achieved as high as 98% in Run 1, when SOUR was in the range of 100-200 mg-O/g-MLVSS/hr. Unexpectedly, the COD removal efficiency in Run 2 to 4 was higher than 92%, on average, where higher HRT and abnormally low SOUR of 20-30 mg-O/g-MLVSS/hr prevailed. It was noted that the ceramic membrane presented a significant soluble nutrient rejection when the microbial metabolism of biological treatment broke down.

Biological nutrient removal and molecular biological characteristics in an anaerobic-multistage anaerobic/oxic (A-MAO) process to treat municipal wastewater.

PubMed

Huang, Xiao; Dong, Wenyi; Wang, Hongjie; Jiang, Shilong

2017-10-01

This study aimed to present an anaerobic-multistage anaerobic/oxic (A-MAO) process to treat municipal wastewater. The average COD, NH 4 + -N, TN, and TP removal efficiency were 91.81%, 96.26%, 83.73% and 94.49%, respectively. Temperature plunge and C/N decrease have a certain impact on the modified process. Characteristics of microbial community, function microorganism, and correlation of microbial community with environmental variables in five compartments were carried out by Illumina Miseq high-throughput sequencing. The differences of microbial community were observed and Blastocatella, Flavobacterium and Pseudomonas were the dominant genus. Nitrosomonas and Nitrospira occupied a dominant position in AOB and NOB, respectively. Rhodospirillaceae and Rhodocyclaceae owned a considerable proportion in phosphorus removal bacteria. DO and COD played significant roles on affecting the microbial components. The A-MAO process in this study demonstrated a high potential for nutrient removal from municipal wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Treatment of phthalic acid esters by electrocoagulation with stainless steel electrodes using dimethyl phthalate as a model compound.

PubMed

Kabdaşli, Işik; Keleş, Asuman; Olmez-Hanci, Tuğba; Tünay, Olcay; Arslan-Alaton, Idil

2009-11-15

In this study, treatment of phthalates by electrocoagulation employing stainless steel electrodes was investigated using dimethyl phthalate (DMP) as a model compound. DMP was completely destructed within 30 min up to the high initial concentration of 100mg/L while total mineralization was also obtained within a couple of hours. The applied current density of 22.5 mA/cm(2) and electrolyte (NaCl) concentrations varying between 1000 and 1500 mg/L as chloride resulted in the highest treatment performance. The initial solution pH (2-6) had practically no effect on the process efficiency. Desorption experiments and the reaction rates obtained for DMP, COD and TOC abatements appeared to be a strong evidence of an oxidative removal mechanism. DMP removal fitted first order kinetics. COD and TOC removals began after the total DMP removal and also fitted first order kinetics. Activated sludge inhibition experiments revealed that toxicity could be significantly reduced by electrocoagulation application.

Performance analysis of a continuous serpentine flow reactor for electrochemical oxidation of synthetic and real textile wastewater: Energy consumption, mass transfer coefficient and economic analysis.

PubMed

Pillai, Indu M Sasidharan; Gupta, Ashok K

2017-05-15

A continuous flow electrochemical reactor was developed, and its application was tested for the treatment of textile wastewater. A parallel plate configuration with serpentine flow was chosen for the continuous flow reactor. Uniparameter optimization was carried out for electrochemical oxidation of synthetic and real textile wastewater (collected from the inlet of the effluent treatment plant). Chemical Oxygen Demand (COD) removal efficiency of 90% was achieved for synthetic textile wastewater (initial COD - 780 mg L -1 ) at a flow rate of 500 mL h -1 (retention time of 6 h) and a current density of 1.15 mA cm -2 and the energy consumption for the degradation was 9.2 kWh (kg COD) -1 . The complete degradation of real textile wastewater (initial COD of 368 mg L -1 ) was obtained at a current density of 1.15 mA cm -2 , NaCl concentration of 1 g L -1 and retention time of 6 h. Energy consumption and mass transfer coefficient of the reactions were calculated. The continuous flow reactor performed better than batch reactor with reference to energy consumption and economy. The overall treatment cost for complete COD removal of real textile wastewater was 5.83 USD m -3 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Tertiary treatment of landfill leachates by adsorption.

PubMed

Marañón, Elena; Castrillón, Leonor; Fernández-Nava, Yoland; Fernández-Méndez, Alejandro; Fernández-Sánchez, Arcadio

2009-08-01

The leachates produced at the municipal solid waste (MSW) landfill of Asturias (Spain) were submitted to a biological treatment consisting of a pressurized nitrification-denitrification process followed by ultrafiltration. The effluent from this treatment plant has a high chemical oxygen demand : biochemical oxygen demand (COD : BOD( 5)) ratio (about 25 : 1). The COD values of the effluent are above the discharge limits permitted by current legislation and therefore require a final treatment. In the present study, adsorption was investigated as a possible post-treatment. Three activated carbons (Organosorb 10, Organosorb 10MB and Filtracarb CC65/1240) were selected and equilibrium and column data were obtained. The best results were obtained with Organosorb 10MB, although adsorption capacities obtained were low and equilibrium was unfavourable. Adsorption capacities ranged between 150 and 157 mg COD g(-1) for an activated carbon dosage of 1 mg L(-1) and between 13.3 and 18.4 mg COD g(-1) for a dosage of 20 mg L(-1). As regards colour, adsorption capacities ranged between 145 and 175 UPtCo g(-1) for the lower dosage and between 16 and 29 UPtCo g(-1) for the higher dosage. Removal efficiency increased with the dosage of activated carbon employed, obtaining maximum COD and colour removals of 63 and 45%, respectively, for a dosage of 20 mg L(-1) after 5 h contact time.

Potential of hydrolysis of particulate COD in extended anaerobic conditions to enhance biological phosphorous removal.

PubMed

Jabari, P; Yuan, Q; Oleszkiewicz, J A

2016-11-01

The effect of anaerobic hydrolysis of particulate COD (pCOD) on biological phosphorous removal in extended anaerobic condition was investigated through (i) sequencing batch reactors (SBR)s with anaerobic hydraulic retention time (HRT) of 0.8, 2, and 4 h; (ii) batch tests using biomass from a full scale biological nutrient removal (BNR) plant; and (iii) activated sludge modeling (BioWin 4.1 simulation). The results from long-term SBRs operation showed that phosphorus removal was correlated to the ratio of filtered COD (FCOD) to total phosphorus (TP) in the influent. Under conditions with low FCOD/TP ratio (average of 20) in the influent, extending anaerobic HRT to 4 h in the presence of pCOD did not significantly improve overall phosphorous removal. During the period with high FCOD/TP ratio (average of 37) in the influent, all SBRs removed phosphorous completely, and the long anaerobic HRT did not have negative effect on overall phosphorous removal. The batch tests also showed that pCOD at different concentration during 4 h test did not affect the rate of anaerobic phosphorus release. The rate of anaerobic hydrolysis of pCOD was significantly low and extending the anaerobic HRT was ineffective. The simulation (BioWin 4.1) of SBRs with low influent FCOD/TP ratio showed that the default kinetics of anaerobic hydrolysis in ASM2d overestimated phosphorous removal in the SBRs (high anaerobic hydrolysis of pCOD). The default anaerobic hydrolysis rate in BioWin 4.1 (ten times lower) could produce similar phosphorous removal to that in the experiment. Results showed that the current kinetics of anaerobic hydrolysis in ASM2d could lead to considerable error in predicting phosphorus removal in processes with extended anaerobic HRT. Biotechnol. Bioeng. 2016;113: 2377-2385. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Removal of volatile organic compounds at extreme shock-loading using a scaled-up pilot rotating drum biofilter.

PubMed

Sawvel, Russell A; Kim, Byung; Alvarez, Pedro J J

2008-11-01

A pilot-scale rotating drum biofilter (RDB), which is a novel biofilter design that offers flexible flow-through configurations, was used to treat complex and variable volatile organic compound (VOC) emissions, including shock loadings, emanating from paint drying operations at an Army ammunition plant. The RDB was seeded with municipal wastewater activated sludge. Removal efficiencies up to 86% and an elimination capacity of 5.3 g chemical oxygen demand (COD) m(-3) hr(-1) were achieved at a filter-medium contact time of 60 sec. Efficiency increased at higher temperatures that promote higher biological activity, and decreased at lower pH, which dropped down to pH 5.5 possibly as a result of carbon dioxide and volatile fatty acid production and ammonia consumption during VOC degradation. In comparison, other studies have shown that a bench-scale RDB could achieve a removal efficiency of 95% and elimination capacity of 331 g COD m(-3) hr(-1). Sustainable performance of the pilot-scale RDB was challenged by the intermittent nature of painting operations, which typically resulted in 3-day long shutdown periods when bacteria were not fed. This challenge was overcome by adding sucrose (2 g/L weekly) as an auxiliary substrate to sustain metabolic activity during shutdown periods.

Performance of different substrates in constructed wetlands planted with E. crassipes treating low-strength sewage under subtropical conditions.

PubMed

Lima, M X; Carvalho, K Q; Passig, F H; Borges, A C; Filippe, T C; Azevedo, J C R; Nagalli, A

2018-07-15

The present study aimed to assess removal potential of chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), total ammonia nitrogen (TAN), total phosphorus (TP) and acetylsalicylic acid (ASA) in synthetic wastewater simulating low-strength sewage by sequencing-batch mode constructed wetlands (CWs). Six CWs with three substrates (gravel, light expanded clay and clay bricks) and one CW of each substrate was planted with E. crassipes to verify the feasibility of using a floating macrophyte in CWs and verify the best optimized substrate. Results showed that the presence of E. crassipes enhanced the removal of COD for systems with gravel, increasing the removal efficiency from 37% in the unplanted system (CW G-U ) to 60% in the planted system (CW G-P ). The vegetated CW with clay bricks (CW B-P ) presented the best performance for both TKN and TAN removal, with maximum removal efficiencies of 68% and 35%, respectively. Phosphorus was observed to be efficiently removed in systems with clay bricks, both planted (CW B-U ) and unplanted (CW B-P ), with mean removal efficiencies of 82% and 87%, respectively, probably via adsorption. It was also observed that after 296days of operation, no desorption or increase on phosphorus in effluent samples were observed, thus indicating that the material was not yet saturated and phosphorus probably presents a strong binding to the media. ASA removal efficiency varied from 34% to 92% in CWs, probably due to plant uptake through roots and microbial biodegradation. Plant direct uptake varied from 4 to 74% of the total nitrogen and from 26 to 71% of the total phosphorus removed in CW G-P , CW C-P and CW B-P . E. crassipes was able to uptake up to 4.19g of phosphorus in CW C-P and 11.84g of nitrogen in CW B-P . The findings on this study suggest that E. crassipes could be used in CWs and clay bricks could significantly enhance phosphorus removal capacity in CWs. Copyright © 2018 Elsevier B.V. All rights reserved.

Performance of Multilevel Contact Oxidation in the Treatment of Wastewater from Automobile Painting Industry

NASA Astrophysics Data System (ADS)

Zhu, Tong; Zhu, Yufang; Fienko, Udo; Yuanhua, Xie; Kuo, Zhang

2017-01-01

A multilevel contact oxidation system was applied in a pilot-scale experiment to treat the automobile painting wastewater, which had poor biodegradability and contained high concentration of Chemical Oxygen Demand (COD). The wastewater used for this experiment study was the actual painting wastewater which had been pre-treated by the physic-chemical process, and its Biological Oxygen Demand (BOD5)/COD was less than 0.1,COD concentration was 800∼1500mg/L. The results showed that the multilevel contact oxidation system could efficiently degrade the COD of the painting wastewater. When the experimental system kept stable operation, the total removal rate of COD and suspended solid (SS) were 84% and 82.5% respectively with the Hydraulic Retention Time (HRT) of 8 hours. Meanwhile, this system had a strong ability to resist the impact of COD concentration change. The COD concentration of final treated wastewater was less than 500 mg/L, which could reach the factory discharge requirement for the paint shop. Besides, this system with simple structure was able to reduce the excess sludge production greatly, which would reduce much cost for the treatment of painting wastewater.

Optimization of moving bed biofilm reactors for oil sands process-affected water treatment: The effect of HRT and ammonia concentrations.

PubMed

Shi, Yijing; Huang, Chunkai; Gamal El-Din, Mohamed; Liu, Yang

2017-11-15

Two moving bed biofilm reactors (MBBRs) were optimized to improve the biodegradation of organic compounds in raw and ozonated OSPW by changing the hydraulic retention time (HRT) and the influent ammonia concentrations. During the five stages, the average COD removal reached 50.8±3.4%, 52.8±6.5%, 54.7±4.3%, 56.3±2.2%, and 58.0±2.3% respectively in raw OSPW MBBR, and 54.6±3.8%, 57.2±7.1%, 55.5±5.8%, 58.3±2.2%, and 60.7±2.3% respectively in ozonated OSPW MBBR. Welch's weighted ANOVA tests show that the increase in ammonia levels significantly improved the COD removal in the two systems, while the HRT was an important parameter for COD decrease in the raw OSPW MBBR. Compared to the HRT, the increase in ammonia concentrations were more beneficial for acid extractable fraction (AEF) degradation and the average AEF removal reached 29.80% (raw OSPW MBBR) and 16.50% (ozonated OSPW MBBR) by the end of the optimization (Stage V; HRT=96h, 60mg/L NH 4 + -N). >98% of the NH 4 + -N was removed in the two MBBR systems, showing good nitrification. Microtoxicity tests showed that no significant correlations were found between HRT/ammonia levels and the OSPW toxicity changes toward V. fischeri. Spearman's rank correlation analysis was applied for q-PCR data, showing that positive correlations between the removal efficiencies of AEF and NSR and NirK gene copies were observed in the raw OSPW MBBR system, while positive correlations between AEF removal efficiency and total bacteria gene, NSR, Nitro, and NirK gene copies were observed in the ozonated OSPW MBBR system. Copyright © 2017 Elsevier B.V. All rights reserved.

Aerobic biological treatment of leachates from municipal solid waste landfill.

PubMed

Andrés, P; Gutierrez, F; Arrabal, C; Cortijo, M

2004-01-01

The main objective of the study was to improve chemical oxygen demand (COD) elimination by secondary biological treatment from leachate of municipal solid waste landfill. This effluent was a supernatant liquid obtained after physicochemical processes and coagulating with Al3+ followed by ammoniacal stripping. First, respirometric assays were carried out to determine the substrate biodegradability. Specific sludge respiration rate (R(s)) vs. concentration of substrate (S), showed an increasing specific rate of assimilation of substrate (Rs), which reached the highest value, when the substrate concentration (COD) was between 75 and 200 mg O2 L(-1). Second, continuous experiments were made in an aerobic digester to test the previous respirometric data and the results showed removal efficiency of COD between 83 and 69%, and a substrate assimilation rate between 1.3 and 3.1 g COD g(-1) volatile suspended solids d(-1).

Biological treatment of winery wastewater: an overview.

PubMed

Andreottola, G; Foladori, P; Ziglio, G

2009-01-01

The treatment of winery wastewater can realised using several biological processes based both on aerobic or anaerobic systems using suspended biomass or biofilms. Several systems are currently offered by technology providers and current research envisages the availability of new promising technologies for winery wastewater treatment. The present paper intends to present a brief state of the art of the existing status and advances in biological treatment of winery wastewater in the last decade, considering both lab, pilot and full-scale studies. Advantages, drawbacks, applied organic loads, removal efficiency and emerging aspects of the main biological treatments were considered and compared. Nevertheless in most treatments the COD removal efficiency was around 90-95% (remaining COD is due to the un-biodegradable soluble fraction), the applied organic loads are very different depending on the applied technology, varying for an order of magnitude. Applied organic loads are higher in biofilm systems than in suspended biomass while anaerobic biofilm processes have the smaller footprint but in general a higher level of complexity.

Treatment of ferrous-NTA-based NO x scrubber solution by an up-flow anaerobic packed bed bioreactor.

PubMed

Chandrashekhar, B; Sahu, Nidhi; Tabassum, Heena; Pai, Padmaraj; Morone, Amruta; Pandey, R A

2015-06-01

A bench scale system consisting of an up-flow packed bed bioreactor (UAPBR) made of polyurethane foam was used for the treatment and regeneration of aqueous solution of ferrous-NTA scrubbed with nitric oxide (NO). The biomass in the UAPBR was sequentially acclimatized under denitrifying and iron reducing conditions using ethanol as electron donor, after which nitric oxide (NO) gas was loaded continuously to the system by absorption. The system was investigated for different parameters viz. pH, removal efficiency of nitric oxide, biological reduction efficiency of Fe(II)NTA-NO and COD utilization. The Fe(II)NTA-NO reduction efficiency reached 87.8 % at a loading rate of 0.24 mmol L(-1) h(-1), while the scrubber efficiency reached more than 75 % with 250 ppm NO. Stover-Kincannon and a Plug-flow kinetic model based on Michaelis-Menten equation were used to describe the UAPBR performance with respect to Fe(II)NTA-NO and COD removal. The Stover-Kincannon model was found capable of describing the Fe(II)NTA-NO reduction (R m = 8.92 mM h(-1) and K NO = 11.46 mM h(-1)) while plug-flow model provided better fit to the COD utilization (U m = 66.62 mg L(-1) h(-1), K COD = 7.28 mg L(-1)). Analyses for pH, Fe(III)NTA, ammonium, nitrite concentration, and FTIR analysis of the medium samples indicated degradation of NTA, which leads to ammonium and nitrite accumulation in the medium, and affect the regeneration process.

Evaluation of the process performance of a down-flow hanging sponge reactor for direct treatment of domestic wastewater in Bangkok, Thailand.

PubMed

Miyaoka, Yuma; Yoochatchaval, Wilasinee; Sumino, Haruhiko; Banjongproo, Pathan; Yamaguchi, Takashi; Onodera, Takashi; Okadera, Tomohiro; Syutsubo, Kazuaki

2017-08-24

This study assesses the performance of an aerobic trickling filter, down-flow hanging sponge (DHS) reactor, as a decentralized domestic wastewater treatment technology. Also, the characteristic eukaryotic community structure in DHS reactor was investigated. Long-term operation of a DHS reactor for direct treatment of domestic wastewater (COD = 150-170 mg/L and BOD = 60-90 mg/L) was performed under the average ambient temperature ranged from 28°C to 31°C in Bangkok, Thailand. Throughout the evaluation period of 550 days, the DHS reactor at a hydraulic retention time of 3 h showed better performance than the existing oxidation ditch process in the removal of organic carbon (COD removal rate = 80-83% and BOD removal rate = 91%), nitrogen compounds (total nitrogen removal rate = 45-51% and NH 4 + -N removal rate = 95-98%), and low excess sludge production (0.04 gTS/gCOD removed). The clone library based on the 18S ribosomal ribonucleic acid gene sequence revealed that phylogenetic diversity of 18S rRNA gene in the DHS reactor was higher than that of the present oxidation ditch process. Furthermore, the DHS reactor also demonstrated sufficient COD and NH 4 + -N removal efficiency under flow rate fluctuation conditions that simulates a small-scale treatment facility. The results show that a DHS reactor could be applied as a decentralized domestic wastewater treatment technology in tropical regions such as Bangkok, Thailand.

Performances and microbial features of an aerobic packed-bed biofilm reactor developed to post-treat an olive mill effluent from an anaerobic GAC reactor

PubMed Central

Bertin, Lorenzo; Colao, Maria Chiara; Ruzzi, Maurizio; Marchetti, Leonardo; Fava, Fabio

2006-01-01

Background Olive mill wastewater (OMW) is the aqueous effluent of olive oil producing processes. Given its high COD and content of phenols, it has to be decontaminated before being discharged. Anaerobic digestion is one of the most promising treatment process for such an effluent, as it combines high decontamination efficiency with methane production. The large scale anaerobic digestion of OMWs is normally conducted in dispersed-growth reactors, where however are generally achieved unsatisfactory COD removal and methane production yields. The possibility of intensifying the performance of the process using a packed bed biofilm reactor, as anaerobic treatment alternative, was demonstrated. Even in this case, however, a post-treatment step is required to further reduce the COD. In this work, a biological post-treatment, consisting of an aerobic biological "Manville" silica bead-packed bed aerobic reactor, was developed, tested for its ability to complete COD removal from the anaerobic digestion effluents, and characterized biologically through molecular tools. Results The aerobic post-treatment was assessed through a 2 month-continuous feeding with the digested effluent at 50.42 and 2.04 gl-1day-1 of COD and phenol loading rates, respectively. It was found to be a stable process, able to remove 24 and 39% of such organic loads, respectively, and to account for 1/4 of the overall decontamination efficiency displayed by the anaerobic-aerobic integrated system when fed with an amended OMW at 31.74 and 1.70 gl-1day-1 of COD and phenol loading rates, respectively. Analysis of 16S rRNA gene sequences of biomass samples from the aerobic reactor biofilm revealed that it was colonized by Rhodobacterales, Bacteroidales, Pseudomonadales, Enterobacteriales, Rhodocyclales and genera incertae sedis TM7. Some taxons occurring in the influent were not detected in the biofilm, whereas others, such as Paracoccus, Pseudomonas, Acinetobacter and Enterobacter, enriched significantly in the biofilter throughout the treatment. Conclusion The silica-bead packed bed biofilm reactor developed and characterized in this study was able to significantly decontaminate anaerobically digested OMWs. Therefore, the application of an integrated anaerobic-aerobic process resulted in an improved system for valorization and decontamination of OMWs. PMID:16595023

Landfill leachate treatment by an experimental subsurface flow constructed wetland in tropical climate countries.

PubMed

Ujang, Z; Soedjono, E; Salim, M R; Shutes, R B

2005-01-01

Municipal leachate was treated in an experimental unit of constructed wetlands of subsurface flow type. The parameters studied were organics (BOD and COD), solids and heavy metals (Zn, Ni, Cu, Cr and Pb). Using two types of emergent plants of Scirpus globulosus and Eriocaulon sexangulare, more than 80% removal was achieved for all the parameters. E. sexangulare removed organics and heavy metals better than Scirpus globulosus. A higher concentration of heavy metals in the influent did not change the removal efficiency.

Investigation on pretreatment of centrifugal mother liquid produced in the production of polyvinyl chloride by air-Fenton technique.

PubMed

Sun, Yingying; Hua, Xiuyi; Ge, Rui; Guo, Aitong; Guo, Zhiyong; Dong, Deming; Sun, Wentian

2013-08-01

Centrifugal mother liquid (CML) is one of the main sources of wastewater produced during the production of polyvinyl chloride in chlor-alkali industry. CML is a typical poorly biodegradable organic wastewater, containing many kinds of refractory pollutants. Specifically, it contains dissolved refractory polymers, especially polyvinyl alcohol (PVA), which can pass though the biotreatment processes and clog the membranes used for further treatment. In this study, to ensure the CML applicable to biotreatment and membrane treatment, a novel efficient and mild technique, air-Fenton treatment, was employed as a pretreatment technique to improve biodegradability of the CML and to break down the polymers in the CML. Firstly, the technique was optimized for the CML treatment by optimizing the main parameters, including the dosage of ferrous sulfate, initial pH of the wastewater, [H2O2]/[Fe(2+)], aeration rate, reaction time, and temperature, based on removal efficiency of COD and PVA from the CML. Then, the optimized technique was tested and evaluated. The results indicated that under the optimized conditions, the air-Fenton treatment could remove 66, 98, and 55 % of the COD, PVA, and TOC, respectively, from the CML. After the treatment, biodegradability of the wastewater increased significantly (BOD/COD increased from 0.31 to 0.68), and almost all of the PVA polymers were removed or broken down. Meanwhile, concentration of the remaining iron ions, which were added during the treatment, was also quite low (only 2.9 mg/L). Furthermore, most of the suspended materials and ammonia nitrogen, and some of the phosphorus in the wastewater were removed simultaneously.

Ozonation and ultrafiltration for the treatment of olive mill wastewaters: effect of key operating conditions and integration schemes.

PubMed

Martins, Rui C; Ferreira, Ana M; Gando-Ferreira, Licínio M; Quinta-Ferreira, Rosa M

2015-10-01

With the objective of reaching suitable techniques for olive mill wastewater treatment, ozonation and ultrafiltration were studied individually and combined. A continuous reactor was run for the treatment of a phenolic mixture mimicking an actual olive mill wastewater (OMW) by ozonation. The effect of the main operating parameters was analysed (pH, liquid flow rate and ozone inlet concentration). The increase of pH and ozone dose improved ozonation efficiency. As expected, the highest residence time led to higher steady-state degradation (35 % of chemical oxygen demand (COD) abatement). Even if the rise on ozone inlet gas concentration was able to remove COD in a higher extent, it should be taken into consideration that with the lowest oxidant load (15 g O3/m(3)), the maximum steady-state biochemical oxygen demand (BOD5)/COD ratio was reached which would reduce the process costs. These operating conditions (pH 9, 1 mL/min of liquid flow rate and 15 g O3/m(3)) were applied to an actual OMW leading to 80 % of phenolic content abatement and 12 % of COD removal at the steady state. Regarding ultrafiltration, it was concluded that the best total phenolic content (TPh) and COD abatement results (55 and 15 %) are attained for pH 9 and using a transmembrane pressure drop of 1 bar. Among the integration schemes that were tested, ultrafiltration followed by ozonation was able to reach 93 and 20 % of TPh and COD depletion, respectively. Moreover, this sequence led to an effluent with a BOD5/COD ratio of about 0.55 which means that it likely can be posteriorly refined in a municipal wastewater treatment plant.

Cosmetic wastewater treatment using the Fenton, Photo-Fenton and H2O2/UV processes.

PubMed

Marcinowski, Piotr P; Bogacki, Jan P; Naumczyk, Jeremi H

2014-01-01

Advanced Oxidation Processes (AOPs), such as the Fenton, photo-Fenton and H2O2/UV processes, have been investigated for the treatment of cosmetic wastewaters that were previously coagulated by FeCl3. The Photo-Fenton process at pH 3.0 with 1000/100 mg L(-1) H2O2/Fe(2+) was the most effective (74.0% Chemical Oxygen Demand (COD) removal). The Fenton process with 1200/500 mg L(-1) H2O2/Fe(2+) achieved a COD removal of 72.0%, and the H2O2/UV process achieved a COD removal of 47.0%. Spreading the H2O2 doses over time to obtain optimal conditions did not improve COD removal. The kinetics of the Fenton and photo-Fenton processes may be described by the following equation: d[COD]/dt = -a[COD] t(m) (t represents time and a and m are constants). The rate of COD removal by the H2O2/UV process may be described by a second-order reaction equation. Head Space, Solid-Phase MicroExtraction, Gas Chromatography and Mass Spectrometry (HS-SPME-GC-MS) were used to identify 48 substances in precoagulated wastewater. Among these substances, 26 were fragrances. Under optimal AOP conditions, over 99% of the identified substances were removed in 120 min.

Simultaneous photocatalytic and microbial degradation of dye-containing wastewater by a novel g-C3N4-P25/photosynthetic bacteria composite

PubMed Central

Zhang, Xinying; Wu, Yan; Xiao, Gao; Tang, Zhenping; Wang, Meiyin; Liu, Fuchang; Zhu, Xuefeng

2017-01-01

Azo dyes are very resistant to light-induced fading and biodegradation. Existing advanced oxidative pre-treatment methods based on the generation of non-selective radicals cannot efficiently remove these dyes from wastewater streams, and post-treatment oxidative dye removal is problematic because it may leave many byproducts with unknown toxicity profiles in the outgoing water, or cause expensive complete mineralization. These problems could potentially be overcome by combining photocatalysis and biodegradation. A novel visible-light-responsive hybrid dye removal agent featuring both photocatalysts (g-C3N4-P25) and photosynthetic bacteria encapsulated in calcium alginate beads was prepared by self-assembly. This system achieved a removal efficiency of 94% for the dye reactive brilliant red X-3b and also reduced the COD of synthetic wastewater samples by 84.7%, successfully decolorized synthetic dye-contaminated wastewater and reduced its COD, demonstrating the advantages of combining photocatalysis and biocatalysis for wastewater purification. The composite apparently degrades X-3b by initially converting the dye into aniline and phenol derivatives whose aryl moieties are then attacked by free radicals to form alkyl derivatives, preventing the accumulation of aromatic hydrocarbons that might suppress microbial activity. These alkyl intermediates are finally degraded by the photosynthetic bacteria. PMID:28273118

How the novel integration of electrolysis in tidal flow constructed wetlands intensifies nutrient removal and odor control.

PubMed

Ju, Xinxin; Wu, Shubiao; Huang, Xu; Zhang, Yansheng; Dong, Renjie

2014-10-01

Intensified nutrient removal and odor control in a novel electrolysis-integrated tidal flow constructed wetland were evaluated. The average removal efficiencies of COD and NH4(+)-N were above 85% and 80% in the two experimental wetlands at influent COD concentration of 300 mg/L and ammonium nitrogen concentration of 60 mg/L regardless of electrolysis integration. Effluent nitrate concentration decreased from 2.5mg/L to 0.5mg/L with the reduction in current intensity from 1.5 mA/cm(2) to 0.57 mA/cm(2). This result reveals the important role of current intensity in nitrogen transformation. Owing to the ferrous and ferric iron coagulant formed through the electro-dissolution of the iron anode, electrolysis integration not only exerted a positive effect on phosphorus removal but also effectively inhibited sulfide accumulation for odor control. Although electrolysis operation enhanced nutrient removal and promoted the emission of CH4, no significant difference was observed in the microbial communities and abundance of the two experimental wetlands. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of the treatability of a winery distillery (vinasse) wastewater by UASB, anoxic-aerobic UF-MBR and chemical precipitation/adsorption.

PubMed

Petta, Luigi; De Gisi, Sabino; Casella, Patrizia; Farina, Roberto; Notarnicola, Michele

2017-10-01

A multi-stage pilot-scale treatment cycle consisting of an Upflow Anaerobic Sludge Blanket reactor (UASB) followed by an anoxic-aerobic Ultra Filtration Membrane Bio Reactor (UF-MBR) and a post treatment based on chemical precipitation with lime or adsorption on Granular Activated Carbons (GAC), was applied in order to evaluate the treatment feasibility of a real winery distillery wastewater at laboratory and bench scale. The wastewater was classified as high strength with acidic pH (3.8), and concentrations of 44,600, 254, 604 and 660 mg/l for COD tot , total nitrogen, total phosphorous and phenols, respectively. The UASB reactor was operated at Organic Loading Rates (OLR) in the range 3.0-11.5 kgCOD tot /m 3 /d achieving treatment efficiency up to 97%, with an observed methane production of 340 L of CH 4 /kgCOD. The MBR system was operated with an organic load in the range 0.070-0.185 kgCOD/kgVSS/d, achieving a removal up to 48%, 67% and 65% of the influent COD, total nitrogen and phenols, respectively. The combination of UASB and UF-MBR treatment units was not effective in phosphate and colour removal assigning to further chemical precipitation and adsorption processes, respectively, their complete removal in order to comply with legal standards for wastewater discharge. Subsequently, the optimization of the investigated treatment chain was assessed by applying a chemical precipitation step upstream and downstream the UASB reactor, and a related treatment unit cost assessment is presented in view of a further technological scale-up. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coagulation-flocculation sequential with Fenton or Photo-Fenton processes as an alternative for the industrial textile wastewater treatment.

PubMed

GilPavas, Edison; Dobrosz-Gómez, Izabela; Gómez-García, Miguel Ángel

2017-04-15

In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al 2 (SO 4 ) 3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al 2 (SO 4 ) 3  at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD 5 /COD ratio from 0.137 to 0.212. Subsequently, the C-F effluent was treated using each of AOPs. Their performances were optimized by the Response Surface Methodology (RSM) coupled with a Box-Behnken experimental design (BBD). The following optimal conditions of both Fenton (Fe 2+ /H 2 O 2 ) and Photo-Fenton (Fe 2+ /H 2 O 2 /UV) processes were found: Fe 2+ concentration = 1 mM, H 2 O 2 dose = 2 mL/L (19.6 mM), and pH = 3. The combination of C-F pre-treatment with the Fenton reagent, at optimized conditions, let to remove 74% of COD during 90 min of the process. The C-F sequential with Photo-Fenton process let to reach 87% of COD removal, in the same time. Moreover, the BOD 5 /COD ratio increased from 0.212 to 0.68 and from 0.212 to 0.74 using Fenton and Photo-Fenton processes, respectively. Thus, the enhancement of biodegradability with the physico-chemical treatment was proved. The depletion of H 2 O 2 was monitored during kinetic study. Strategies for improving the reaction efficiency, based on the H 2 O 2 evolution, were also tested. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.

PubMed

Dumas, C; Perez, S; Paul, E; Lefebvre, X

2010-04-01

The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. Copyright 2009 Elsevier Ltd. All rights reserved.

A new installation for treatment of road runoff: up-flow filtration by porous polypropylene media.

PubMed

Lee, B C; Matsui, S; Shimizu, Y; Matsuda, T; Tanaka, Y

2005-01-01

We installed a new device on a paved road to treat runoff from a roadway surface. All the stormwater runoff was transferred into the device and the runoff equivalent to 10 mm/hr or less was treated. The treatment method consists of sedimentation and up-flow filtration with porous polypropylene (PPL) processes. The treated runoff was discharged into the existing storm drainage pipe. The average removal efficiency of the initial runoff at the beginning of rainfall which has high pollution intensity was about 90% for SS, about 70% for COD, about 40% for total phosphorus (T-P), about 80% for Pb and Cd, about 70% for Zn, Cu, Mn and Cr, and about 60% for polycyclic aromatic hydrocarbons (PAHs). The overall removal efficiencies of the experiment that ran for four months remained > 60% of SS, > 40% of COD, > 60% of heavy metals, and > 40% of PAHs. The PPL is excellent for removing smaller size particulates of suspended solids, which originate basically from diesel exhaust, as well as larger size particulates from automobile tires, asphalt roads, and other accumulated source(s) of clay and sand, etc.

Continuous energy recovery and nutrients removal from molasses wastewater by synergistic system of dark fermentation and algal culture under various fermentation types.

PubMed

Ren, Hong-Yu; Kong, Fanying; Ma, Jun; Zhao, Lei; Xie, Guo-Jun; Xing, Defeng; Guo, Wan-Qian; Liu, Bing-Feng; Ren, Nan-Qi

2018-03-01

Synergistic system of dark fermentation and algal culture was initially operated at batch mode to investigate the energy production and nutrients removal from molasses wastewater in butyrate-type, ethanol-type and propionate-type fermentations. Butyrate-type fermentation was the most appropriate fermentation type for the synergistic system and exhibited the accumulative hydrogen volume of 658.3 mL L -1 and hydrogen yield of 131.7 mL g -1 COD. By-products from dark fermentation (mainly acetate and butyrate) were further used to cultivate oleaginous microalgae. The maximum algal biomass and lipid content reached 1.01 g L -1 and 38.5%, respectively. In continuous operation, the synergistic system was stable and efficient, and energy production increased from 8.77 kJ L -1  d -1 (dark fermentation) to 17.3 kJ L -1  d -1 (synergistic system). Total COD, TN and TP removal efficiencies in the synergistic system reached 91.1%, 89.1% and 85.7%, respectively. This study shows the potential of the synergistic system in energy recovery and wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

[NH4+-N removal stability of zeolite media packed multistage-biofilm system for coke-plant wastewater treatment].

PubMed

Zhao, Wen-Tao; Huang, Xia; He, Miao; Zhang, Peng-Yi; Zuo, Chen-Yan

2009-02-15

The practical ammonia stripping effectiveness of coke-plant wastewater treatment may vary widely, and high NH4+-N shock loading will lead to the fluctuation of residual NH4+-N concentration of biological effluent. A zeolite media packed multistage-biofilm system (ZMBS) was used for coke-plant wastewater treatment for enhancing the NH4+-N treatment ability of the bio-system to shock loading, as well as achieving high COD removal efficiency. Treatment performance during steady-state and shock loading and transformation of organic pollutants in the system were investigated systematically. The experiment results indicated that when the system was operated at NH4+-N loading 0.21 kg/(m3 x d) and COD loading < or = 1.35 kg/(m3 x d), the average effluent NH4+-N and COD concentrations were (2.2 +/- 1.2) mg/L, (228 +/- 60) mg/L with average removal efficiencies of (99.1 +/- 0.5)% and (86.0 +/- 2.6)%. During the twice NH4+-N shock loadings [0.03 kg/(m3 x d) and 0.06 kg/(m3 x d)], ZMBS showed a strong resisting ability with average removal efficiencies of 99.0% and 92.9% higher than those of a compared system's 96.8% and 89.3%. By monitoring the change of water quality along the length of the ZMBS's cells, two function zones for different pollutant removal were found to exist, named as decarbonization/nitrification (C/N) zone and nitrification (N) zone, and the NH4+-N removal rate in N zone was 2-8 times as that in C/N zone. TOC concentrations of organic matters with relative molecular weight < 1 x 10(3), 1 x 10(3) to 1 x 10(4), and > 1 x 10(4), were 227.6, 104.8 and 35.0 mg/L in raw wastewater, and 31.2, 22.9 and 31.5 mg/L in the effluent, respectively. Organic matters with relative molecular weight < 1 x 10(3) and 1 x 10(3) to 1 x 10(4) in raw wastewater were removed effectively by ZMBS, but those with relative molecular weight > 1x 10(3) were the main remained substances in the effluent.

Role of UASBs in River Water Quality Conservation in India

NASA Astrophysics Data System (ADS)

Gali, Veeresh; Thakur, Manisha; Gupta, Ashok Kumar; Ganguly, Rajiv

2018-03-01

Appropriate low-cost treatment technologies are a prerequisite for sound management of natural water resources against pollution in developing countries. Among the existing technologies available, UASB is found to be economically viable for India when considering all factors including operation and maintenance cost and treatment efficiency. However, this technology suffers setbacks in meeting the effluent guidelines prescribed by the government of India. Post treatment is supplemental to this process to meet the effluent standards in terms of removal of organic matter, suspended solids, pathogens and nutrients. Recent stringent effluent guidelines notified by the Ministry of Environment, Forests and Climate Change, Government of India has further reduced the limits of BOD by 3 times, COD and TSS by 5 times, NH4-N and total Nitrogen by 10 times as compared to the previous guidelines. Fecal Coliforms has been specified as <100MPN/100mL. In this paper, the present scenario of UASB based STPs and their role in river conservation is reviewed against the backdrop of stringent effluent guidelines. The minimum removal rates of BOD, COD and TSS in these plants are around 42 - 44% and the average removal rates are reported to be 66%, 61% and 65% respectively. The enhanced removal of BOD (97%), COD (98%) and TSS has been reported in STPs in conjunction with post treatment facilities such as facultative aerated lagoons, aeration tanks and polishing ponds.

Inhibitory Effects of Silver Nanoparticles on Removal of Organic Pollutants and Sulfate in an Anaerobic Biological Wastewater Treatment Process.

PubMed

Rasool, Kashif; Lee, Dae Sung

2016-05-01

The increasing use of silver nanoparticles (AgNPs) in commercial products and industrial processes raises issues regarding the toxicity of sludge biomass in biological wastewater treatment plants, due to potential antimicrobial properties. This study investigated the effects of AgNPs on removal of organic pollutants and sulfate in an anaerobic biological sulfate reduction process. At AgNPs concentrations of up to 10 mg/L, no significant inhibition of sulfate and COD removal was observed. However, at higher concentrations (50-200 mg/L) sulfate and COD removal efficiencies were significantly decreased to 51.8% and 33.6%, respectively. Sulfate and COD reduction followed first-order kinetics at AgNPs concentrations of up to 10 mg/L and second-order kinetics at AgNPs concentrations of 50-200 mg/L. Lactate dehydrogenase release profiles showed increases in cytotoxicity at AgNPs concentrations greater than 50 mg/L suggesting cell membrane disruption. Analysis of extracellular polymeric substances (EPS) from sulfidogenic sludge biomass and of Fourier transform infrared (FT-IR) spectra showed a decrease in concentrations of carbohydrates, proteins, humic substances, and lipids in the presence of AgNPs. Moreover, the interaction of AgNPs with sludge biomass and the damage caused to cell walls were confirmed through scanning electron microscopy with energy dispersive X-ray spectroscopy.

Sequencing Batch Reactor (SBR) for the removal of Hg2+ and Cd2+ from synthetic petrochemical factory wastewater.

PubMed

Malakahmad, Amirhossein; Hasani, Amirhesam; Eisakhani, Mahdieh; Isa, Mohamed Hasnain

2011-07-15

Petrochemical factories which manufacture vinyl chloride monomer and poly vinyl chloride (PVC) are among the largest industries which produce wastewater contains mercury and cadmium. The objective of this research is to evaluate the performance of a lab-scale Sequencing Batch Reactor (SBR) to treat a synthetic petrochemical wastewater containing mercury and cadmium. After acclimatization of the system which lasted 60 days, the SBR was introduced to mercury and cadmium in low concentrations which then was increased gradually to 9.03±0.02 mg/L Hg and 15.52±0.02 mg/L Cd until day 110. The SBR performance was assessed by measuring Chemical Oxygen Demand, Total and Volatile Suspended Solids as well as Sludge Volume Index. At maximum concentrations of the heavy metals, the SBR was able to remove 76-90% of Hg(2+) and 96-98% of Cd(2+). The COD removal efficiency and MLVSS (microorganism population) in the SBR was affected by mercury and cadmium concentrations in influent. Different species of microorganisms such as Rhodospirilium-like bacteria, Gomphonema-like algae, and sulfate reducing-like bacteria were identified in the system. While COD removal efficiency and MLVSS concentration declined during addition of heavy metals, the appreciable performance of SBR in removal of Hg(2+) and Cd(2+) implies that the removal in SBR was not only a biological process, but also by the biosorption process of the sludge. Copyright © 2011 Elsevier B.V. All rights reserved.

Removal of Heavy Metals from Solid Wastes Leachates Coagulation-Flocculation Process

NASA Astrophysics Data System (ADS)

Yousefi, Z.; Zazouli, M. A.

The main objectives of present research were to determine heavy metals (Ni, Cd, Cr, Zn and Cu) and COD concentration in raw leachate in Esfahan (Iran) composting plant and to examine the application of coagulation-flocculation process for the treatment of raw leachates. Jar-test experiments were employed in order to determine the optimum conditions (effective dosage and optimum pH) for the removal of COD and heavy metals. Alum (aluminum sulphate) and Ferric chloride were tested as conventional coagulants. Ten times had taken sampling from leachates as standard methods in the composting plant prior to composting process. The results showed that Leachate pH was 4.3-5.9 and the average was 4.98±0.62. The concentration of Leachate pollutants were more than effluent standard limits (Environment protection Agency). And also the results indicated, Cd and Zn with concentration 0.46±0.41 and 5.81±3.69 mg L-1, had minimum and maximum levels, respectively. The results of coagulation and flocculation tests showed that in optimum conditions, the removal efficiency of heavy metals and COD by using alum were 77-91 and 21%, respectively. While removal of heavy metals and COD by ferric chloride were 68-85.5% and 28%, respectively. Also the residues of heavy metals after treatment get to under of standard limits of Iran EPA. The results have indicated optimum pH of two coagulants for leachate treatment was 6.5 and 10 and also effective coagulant dosages were 1400 and 1000 mg L-1 for alum and ferric chloride, respectively. In view of economical, ferric chloride is cost benefit. The physico-chemical process may be used as a useful pretreatment step, especially for fresh leachates.

Advanced treatment of biotreated textile industry wastewater with ozone, virgin/ozonated granular activated carbon and their combination.

PubMed

Arslan-Alaton, Idil; Seremet, Ozden

2004-01-01

Biotreated textile wastewater (CODo = 248 mg L(-1); TOCo = 58 mg L(-1); A620 = 0.007 cm(-1); A525 = 0.181 cm(-1); A436 = 0.198 cm(-1)) was subjected to advanced treatment with ozonation, granular activated carbon (GAC) adsorption in serial and simultaneous applications. Experiments were conducted to investigate the effects of applied ozone dose, ozone absorption rate, specific ozone absorption efficiency, GAC dose, and reaction pH on the treatment performance of the selected tertiary treatment scheme. In separate experiments, the impact of virgin GAC ozonation on its adsorptive capacity for biotreated and biotreated + ozonated textile effluent was also investigated. Ozonation appeared to be more effective for decolorization (kd = 0.15 min(-1) at pH = 3), whereas GAC adsorption yielded higher COD removal rates (54% at pH = 3). It was also found that GAC addition (4 g/L) at pH = 7 and 9 enhanced the COD abatement rate of the ozonation process significantly and that the sequential application of ozonation (at pH = 3-11, 675 mg L(-1) O3) followed by GAC adsorption (at pH = 3-7, 10 g L(-1) GAC) resulted in the highest treatment performances both in terms of color and COD reduction. Simultaneous application of GAC and ozone at acidic and alkaline pH seriously inhibited COD abatement rates as a consequence of competitive adsorption and partial oxidation of textile components and GAC. It could also be established that ozone absorption efficiency decreased after color removal was complete. Ozonation of biotreated textile wastewater with 113 mg L(-1) ozone resulted in an appreciable enhancement of GAC adsorptive capacity in terms of residual color removal. Ozonation of GAC at relatively low doses (= 10.8 mg/g GAC) did not improve its overall adsorption capacity.

Influence of carbon source on nutrient removal performance and physical-chemical characteristics of aerobic granular sludge.

PubMed

Lashkarizadeh, Monireh; Yuan, Qiuyan; Oleszkiewicz, Jan A

2015-01-01

The impact of carbon source variation on the physical and chemical characteristics of aerobic granular sludge and its biological nutrient (nitrogen and phosphorus) removal performance was investigated. Two identical sequencing batch reactors, R1 and R2, were set up. Granular biomass was cultivated to maturity using acetate-based synthetic wastewater. After mature granules in both reactors with simultaneous chemical oxygen demand (COD), ammonium and phosphorus removal capability were achieved, the feed of R2 was changed to municipal wastewater and R1 was continued on synthetic feed as control. Biological phosphorus removal was completely inhibited in R2 due to lack of readily biodegradable COD; however, the biomass maintained high ammonium and COD removal efficiencies. The disintegration of the granules in R2 occurred during the first two weeks after the change of feed, but it did not have significant impacts on settling properties of the sludge. Re-granulation of the biomass in R2 was then observed within 30 d after granules' disintegration when the biomass acclimated to the new substrate. The granular biomass in R1 and R2 maintained a Sludge Volume Index close to 60 and 47 mL g(-1), respectively, during the experimental period. It was concluded that changing the carbon source from readily biodegradable acetate to the more complex ones present in municipal wastewater did not have significant impacts on aerobic granular sludge characteristics; it particularly did not affect its settling properties. However, sufficient readily biodegradable carbon would have to be provided to maintain simultaneous biological nitrate and phosphorus removal.

Simulated sugar factory wastewater remediation kinetics using algal-bacterial raceway reactor promoted by polyacrylate polyalcohol.

PubMed

Memon, Abdul Rehman; Andresen, John; Habib, Muddasar; Jaffar, Muhammad

2014-04-01

The remediation kinetics of simulated sugar factory wastewater (SFW) using an algal-bacterial culture (ABC) of Chlorella vulgaris in association with Pseudomonas putida in a raceway reactor was found to be enhanced by 89% with the addition of 80ppm of copolymer Polyacrylate polyalcohol (PAPA). This was achieved by efficient suspension of the ABC throughout the water body maintaining optimum pH and dissolved oxygen that led to rapid COD removal and improved algal biomass production. The suspension of the ABC using the co-polymer PAPA maintained a DO of 8-10mgl(-1) compared to 2-3mgl(-1) when not suspended. As a result, the non-suspended ABC only achieved a 50% reduction in COD after 96h compared to a 89% COD removal using 80ppm PAPA suspension. In addition, the algae biomass increased from 0.4gl(-1)d(-1) for the non-suspended ABC to 1.1gl(-1)d(-1) when suspended using 80ppm PAPA. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemically pretreating slaughterhouse solid waste to increase the efficiency of anaerobic digestion.

PubMed

Flores-Juarez, Cyntia R; Rodríguez-García, Adrián; Cárdenas-Mijangos, Jesús; Montoya-Herrera, Leticia; Godinez Mora-Tovar, Luis A; Bustos-Bustos, Erika; Rodríguez-Valadez, Francisco; Manríquez-Rocha, Juan

2014-10-01

The combined effect of temperature and pretreatment of the substrate on the anaerobic treatment of the organic fraction of slaughterhouse solid waste was studied. The goal of the study was to evaluate the effect of pretreating the waste on the efficiency of anaerobic digestion. The effect was analyzed at two temperature ranges (the psychrophilic and the mesophilic ranges), in order to evaluate the effect of temperature on the performance of the anaerobic digestion process for this residue. The experiments were performed in 6 L batch reactors for 30 days. Two temperature ranges were studied: the psychrophilic range (at room temperature, 18°C average) and the mesophilic range (at 37°C). The waste was pretreated with NaOH before the anaerobic treatment. The result of pretreating with NaOH was a 194% increase in the soluble chemical oxygen demand (COD) with a dose of 0.6 g NaOH per g of volatile suspended solids (VSS). In addition, the soluble chemical oxygen demand/total chemical oxygen demand ratio (sCOD/tCOD) increased from 0.31 to 0.7. For the anaerobic treatment, better results were observed in the mesophilic range, achieving 70.7%, 47% and 47.2% removal efficiencies for tCOD, total solids (TS), and volatile solids (VS), respectively. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Optimization of leachate treatment using persulfate/H2O2 based advanced oxidation process: case study: Deir El-Balah Landfill Site, Gaza Strip, Palestine.

PubMed

Hilles, Ahmed H; Abu Amr, Salem S; Hussein, Rim A; Arafa, Anwar I; El-Sebaie, Olfat D

2016-01-01

The objective of this study was to investigate the performance of employing H2O2 reagent in persulfate activation to treat stabilized landfill leachate. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as persulfate and H2O2 dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following two responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD) and NH3-N removal. The obtained optimum conditions included a reaction time of 116 min, 4.97 g S2O8(2-), 7.29 g H2O2 dosage and pH 11. The experimental results were corresponding well with predicted models (COD and NH3-N removal rates of 81% and 83%, respectively). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as persulfate only and H2O2 only, to evaluate its effectiveness. The combined method (i.e., /S2O8(2-)/H2O2) achieved higher removal efficiencies for COD and NH3-N compared with other studied applications.

Optimization of Fenton's oxidation of herbicide dicamba in water using response surface methodology

NASA Astrophysics Data System (ADS)

Sangami, Sanjeev; Manu, Basavaraju

2017-12-01

In this study Fenton's oxidation of dicamba in aqueous medium was investigated by using the response surface methodology. The influence of H2O2/COD ( A), H2O2/Fe2+ ( B), pH ( C) and reaction time ( D) as independent variables were studied on two responses (COD and dicamba removal efficiency). The dosage of H2O2 (5.35-17.4 mM) and Fe2+ (0.09-2.13 mM) were varied and optimum percentage removal of dicamba of 84.01% with H2O2 and Fe2+ dosage of 11.38 and 0.33 mM respectively. The whole oxidation process was monitored by high performance liquid chromatography (HPLC) along with liquid chromatography/mass spectrometry (LC/MS). It was found that 82% of dicamba was mineralized to oxalic acid, chloride ion, CO2 and H2O, which was confirmed with COD removal of 81.53%. The regression analysis was performed, in which standard deviation (<4%), coefficient of variation (<8), F value (Fisher's Test) (>2.74), coefficient of correlation ( R 2 = R_{adj}2) and adequate precision (>12) were in good agreement with model values. Finally, the treatment process was validated by performing the additional experiments.

Organics removal, nitrogen removal and N2O emission in subsurface wastewater infiltration systems amended with/without biochar and sludge.

PubMed

Sun, Yafei; Qi, Shiyue; Zheng, Fanping; Huang, Linli; Pan, Jing; Jiang, Yingying; Hou, Wanyuan; Xiao, Lu

2018-02-01

Organics removal, nitrogen removal, N 2 O emission and nitrogen removal functional gene abundances in four subsurface wastewater infiltration systems (SWISs), named SWIS A (no intermittent aeration without biochar and sludge), SWIS B (no intermittent aeration with biochar and sludge), SWIS C (intermittent aeration without biochar and sludge), SWIS D (intermittent aeration with biochar and sludge) were investigated. Intermittent aeration enhanced chemical oxygen demand (COD), ammonia nitrogen (NH 4 + -N), total nitrogen (TN) removal and the abundances of nitrogen removal functional genes (amoA, nxrA, napA, narG, nirS, nirK, qnorB and nosZ) compared to non-aerated SWISs. High COD (95.4 ± 0.2%), NH 4 + -N (96.2 ± 0.6%), TN (86.4 ± 0.5%) removal efficiencies and low N 2 O emission rate (18.4 mg/(m 2  d)) were obtained simultaneously in intermittent aerated SWIS amended with biochar and sludge. The results suggested that intermittent aerated SWISs amended with biochar and sludge could be an effective and appropriate method for improving treatment performance and reducing N 2 O emission. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methanogenic degradation of toilet-paper cellulose upon sewage treatment in an anaerobic membrane bioreactor at room temperature.

PubMed

Chen, Rong; Nie, Yulun; Kato, Hiroyuki; Wu, Jiang; Utashiro, Tetsuya; Lu, Jianbo; Yue, Shangchao; Jiang, Hongyu; Zhang, Lu; Li, Yu-You

2017-03-01

Toilet-paper cellulose with rich but refractory carbon sources, are the main insoluble COD fractions in sewage. An anaerobic membrane bioreactor (AnMBR) was configured for sewage treatment at room temperature and its performance on methanogenic degradation of toilet paper was highlighted. The results showed, high organic removal (95%), high methane conversion (90%) and low sludge yield (0.08gVSS/gCOD) were achieved in the AnMBR. Toilet-paper cellulose was fully biodegraded without accumulation in the mixed liquor and membrane cake layer. Bioconversion efficiency of toilet paper approached 100% under a high organic loading rate (OLR) of 2.02gCOD/L/d and it could provide around 26% of total methane generation at most of OLRs. Long sludge retention time and co-digestion of insoluble/soluble COD fractions achieving mutualism of functional microorganisms, contributed to biodegradation of toilet-paper cellulose. Therefore the AnMBR successfully implemented simultaneously methanogenic bioconversion of toilet-paper cellulose and soluble COD in sewage at room temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of process variables on the sulfate reduction process in bioreactors treating metal-containing wastewaters: factorial design and response surface analyses.

PubMed

Villa-Gomez, D K; Pakshirajan, K; Maestro, R; Mushi, S; Lens, P N L

2015-07-01

The individual and combined effect of the pH, chemical oxygen demand (COD) and SO4 (2-) concentration, metal to sulfide (M/S(2-)) ratio and hydraulic retention time (HRT) on the biological sulfate reduction (SR) process was evaluated in an inverse fluidized bed reactor by factorial design analysis (FDA) and response surface analysis (RSA). The regression-based model of the FDA described the experimental results well and revealed that the most significant variable affecting the process was the pH. The combined effect of the pH and HRT was barely observable, while the pH and COD concentration positive effect (up to 7 and 3 gCOD/L, respectively) enhanced the SR process. Contrary, the individual COD concentration effect only enhanced the COD removal efficiency, suggesting changes in the microbial pathway. The RSA showed that the M/S(2-) ratio determined whether the inhibition mechanism to the SR process was due to the presence of free metals or precipitated metal sulfides.

Investigation of endogenous biomass efficiency in the treatment of unhairing effluents from the tanning industry.

PubMed

Mlaik, Najwa; Bouzid, Jalel; Gharsallah, Neji; Belbahri, Lassad; Woodward, Steve; Mechichi, Tahar

2009-08-01

The tanning industry is of great economic importance worldwide; however, the potential environmental impact of tanning is significant. An important component in tanning is the removal of hair from the hide (unhairing), a process which generates considerable amounts of toxic effluent characterized by a high concentration of sulphur, rich mineral compounds, a high alkalinity and a high organic load. The purpose of the work described here was to evaluate the biodegradability of the unhairing wastewater by endogenous biomass in batch culture and continuous systems. The detoxification of the effluent was assessed by seed germination tests. The batch culture experiments showed that variations in COD, temperature and pH significantly affected the endogenous biomass growth and activity. The optimal treatment condition corresponded to an initial COD of 6 g/L, pH of 7 and 30 degrees C. Under continuous culture conditions, the reactor was fed for 48 days with the unhairing effluent. The optimal COD removal efficiency was 85.5%. During treatment, a transformation of sulphides into thiosulphates and then sulphates was also observed. The effect of untreated and treated unhairing wastewater on seed germination of different plant species was studied. The data suggested that treatment decreased the wastewater toxicity. Indeed, germination was inhibited when the effluent dilution was lower than 20% and 10% for treated and untreated wastewater, respectively.

Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system.

PubMed

Oosterkamp, Margreet J; Méndez-García, Celia; Kim, Chang-H; Bauer, Stefan; Ibáñez, Ana B; Zimmerman, Sabrina; Hong, Pei-Ying; Cann, Isaac K; Mackie, Roderick I

2016-01-01

This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40 °C) and thermophilic (55 °C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Energy and sugar cane stillage have a high chemical oxygen demand (COD of 43 and 30 g/L, respectively) and low pH (pH 4.3). Furthermore, the acetate concentration in sugar cane stillage was high (45 mM) but was not detected in energy cane stillage. There was also a high amount of lactate in both types of stillage (35-37 mM). The amount of sugars was 200 times higher in energy cane stillage compared to sugar cane stillage. Although there was a high concentration of sulfate (18 and 23 mM in sugar and energy cane stillage, respectively), both thin stillages were efficiently digested anaerobically with high COD removal under mesophilic and thermophilic temperature conditions and with an organic loading rate of 15-21 g COD/L/d. The methane production rate was 0.2 L/g COD, with a methane percentage of 60 and 64, and 92 and 94 % soluble COD removed, respectively, by the mesophilic and thermophilic reactors. Although both treatment processes were equally efficient, there were different microbial communities involved possibly arising from the differences in the composition of energy cane and sugar cane stillage. There was more acetic acid in sugar cane stillage which may have promoted the occurrence of aceticlastic methanogens to perform a direct conversion of acetate to methane in reactors treating sugar cane stillage. Results showed that thin stillage contains easily degradable compounds suitable for anaerobic digestion and that hybrid reactors can efficiently convert thin stillage to methane under mesophilic and thermophilic conditions. Furthermore, we found that optimal conditions for biological treatment of thin stillage were similar for both mesophilic and thermophilic reactors. Bar-coded pyrosequencing of the 16S rRNA gene identified different microbial communities in mesophilic and thermophilic reactors and these differences in the microbial communities could be linked to the composition of the thin stillage.

Dry anaerobic co-digestion of cow dung with pig manure for methane production.

PubMed

Li, Jianzheng; Jha, Ajay Kumar; Bajracharya, Tri Ratna

2014-07-01

The performance of dry anaerobic digestions of cow dung, pig manure, and their mixtures into different ratios were evaluated at 35 ± 1 °C in single-stage batch reactors for 63 days. The specific methane yields were 0.33, 0.37, 0.40, 0.38, 0.36, and 0.35 LCH4/gVSr for cow dung to pig manure ratios of 1:0, 4:1, 3:2, 2:3, 1:4, and 0:1, respectively, while volatile solid (VS) and chemical oxygen demand (COD) removal efficiencies were 48.59, 50.79, 53.20, 47.73, 46.10, and 44.88 % and 55.44, 57.96, 60.32, 56.96, 53.32, and 50.86 %, respectively. The experimental results demonstrated that the co-digestions resulted in 5.10-18.01 % higher methane yields, 2.03-12.95 % greater VS removals, 2.98-12.52 % greater COD degradation and so had positive synergism. The various mixtures of pig manure with cow dung might persuade a better nutrient balance and dilution of high ammonia concentration in pig manure and therefore enhanced digester performance efficiency and higher biogas yields. The dry co-digestion of 60 % cow dung and 40 % pig manure achieved the highest methane yield and the greatest organic materials removal efficiency than other mixtures and controls.

Influence of co-substrate on textile wastewater treatment and microbial community changes in the anaerobic biological sulfate reduction process.

PubMed

Rasool, Kashif; Mahmoud, Khaled A; Lee, Dae Sung

2015-12-15

This study investigated the anaerobic treatment of sulfate-rich synthetic textile wastewater in three sulfidogenic sequential batch reactors (SBRs). The experimental protocol was designed to examine the effect of three different co-substrates (lactate, glucose, and ethanol) and their concentrations on wastewater treatment performance. Sulfate reduction and dye degradation were improved when lactate and ethanol were used as electron donors, as compared with glucose. Moreover, under co-substrate limited concentrations, color, sulfate, and chemical oxygen demand (COD) removal efficiencies were declined. By reducing co-substrate COD gradually from 3000 to 500 mg/L, color removal efficiencies were decreased from 98.23% to 78.46%, 63.37%, and 69.10%, whereas, sulfate removal efficiencies were decreased from 98.42%, 82.35%, and 87.0%, to 30.27%, 21.50%, and 10.13%, for lactate, glucose, and ethanol fed reactors, respectively. Fourier transform infrared spectroscopy (FTIR) and total aromatic amine analysis revealed lactate to be a potential co-substrate for further biodegradation of intermediate metabolites formed after dye degradation. Pyrosequencing analysis showed that microbial community structure was significantly affected by the co-substrate. The reactor with lactate as co-substrate showed the highest relative abundance of sulfate reducing bacteria (SRBs), followed by ethanol, whereas the glucose-fed reactor showed the lowest relative abundance of SRB. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of the efficiency and economic viability of various methods of treatment of sanitary landfill leachate.

PubMed

Gupta, S K; Singh, Gurdeep

2007-12-01

This study assesses the efficiency of various physico-chemical, biological and other tertiary methods for treating leachate. An evaluation study on the treatability of the leachate from methane phase bed (MPB) reactor indicated that at an optimum hydraulic retention time of 6 days, the efficiency of the reactor in terms of biological oxygen demand (BOD) and chemical oxygen demand (COD) removal was 91.29 and 82.69%, respectively. Recycling of the treated leachate through the municipal solid waste layers in the leachate recycling unit (LRU) resulted in a significant increase in the biodegradation of organics present in the leachate. Optimum BOD and COD removal efficiencies were achieved at the third recycle; additional recycling of the leachate did not produce any significant improvement. Physico-chemical treatment of the leachate demonstrated that alum and lime (Option 2) were more economical than coagulants lime and MgCO(3). A cost analysis of the economics of the various treatments revealed that the alternative treatment consisting of a MPB bed followed by a LRU and aerated lagoon is the most cost-effective treatment. However, the alternative consisting of a MPB followed by the LRU and a soil column, which is slightly more costly, would be the most appropriate treatment when adequate land is readily available.

[Air stripping-UASB process for the treatment of evaporator condensate from a Kraft pulp mill].

PubMed

Zhou, Wei-li; Qin, Xiao-peng; Yu, Jun; Imai, Tsuyoshi; Ukita, Masao

2006-04-01

Evaporator condensate from a kraft pulp mill is characterized by high temperature, high strength, poor nutrition, and some odor and inhibitive materials. In this study, air stripping-UASB process was developed to treat the wastewater from a kraft pulp mill. The lab scale study demonstrated that air stripping process removed 70%-80% of the volatile organic sulfur compounds. After that, the UASB reactor showed high efficiency, at the organic loading rate (COD) of 30 kg x (m3 x d)(-1), COD removal was retained about 95%. On the other hand, the inoculated granules were broken in the new surroundings and were replaced with the newly formed granules The scanning electronic microscope (SEM) observation showed wide difference of the predominant anaerobic microorganisms in the seed and newly formed granules.

Removal of antibiotics from piggery wastewater by biological aerated filter system: Treatment efficiency and biodegradation kinetics.

PubMed

Chen, Jun; Liu, You-Sheng; Zhang, Jin-Na; Yang, Yong-Qiang; Hu, Li-Xin; Yang, Yuan-Yuan; Zhao, Jian-Liang; Chen, Fan-Rong; Ying, Guang-Guo

2017-08-01

This study aimed to investigate the removal efficiency and mechanism for antibiotics in swine wastewater by a biological aerated filter system (BAF system) in combination with laboratory aerobic and anaerobic incubation experiments. Nine antibiotics including sulfamonomethoxine, sulfachloropyridazine, sulfamethazine, trimethoprim, norfloxacin, ofloxacin, lincomycin, leucomycin and oxytetracycline were detected in the wastewater with concentrations up to 192,000ng/L. The results from this pilot study showed efficient removals (>82%) of the conventional wastewater pollutants (BOD 5 , COD, TN and NH 3 -N) and the detected nine antibiotics by the BAF system. Laboratory simulation experiment showed first-order dissipation kinetics for the nine antibiotics in the wastewater under aerobic and anaerobic conditions. The biodegradation kinetic parameters successfully predicted the fate of the nine antibiotics in the BAF system. This suggests that biodegradation was the dominant process for antibiotic removal in the BAF system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Treatment of purified terephthalic acid wastewater using a bio-waste-adsorbent bagasse fly ash (BFA).

PubMed

Verma, Shilpi; Prasad, Basheshwar; Mishra, Indra Mani

2017-01-01

Purified terephthalic acid (PTA) plant of a petrochemical unit generates wastewater having high pollution load. Acid treatment of this wastewater reduces the chemical oxygen demand (COD) load by more than 50%, still leaving substantial COD load (>1500 mg/L) which should be removed. The present study reports on the use of a bio-waste-adsorbent bagasse fly ash (BFA) for the reduction of COD and other recalcitrant acids from this wastewater. The BFA showed basic character and was mesoporous with a BET specific surface area of 82.4 m 2 /g. Optimum conditions for the adsorptive treatment of acid-pretreated PTA wastewater were found to be as follows: initial pH (pH i ) = 4, BFA dosage = 15 g/L, and contact time = 3 h. Adsorption treatment resulted in 58.2% removal of COD, 96.3% removal of terephthalic acid (TA), and 99.9% removal of benzoic acid (BA). TA and BA were removed from the pretreated PTA wastewater through precipitation and sedimentation of un-dissociated acid molecules inside the mesopores of the BFA. The results showed that the COD removed by the BFA followed pseudo-second-order kinetics. Equilibrium sorption data were best correlated by the Freundlich isotherm. The process of adsorptive removal of COD was found to be exothermic. The change in the Gibbs free energy was found to be negative, suggesting that the adsorption process is spontaneous and feasible for the treatment of PTA wastewater.

Evaluating the photo-catalytic application of Fenton's reagent augmented with TiO(2) and ZnO for the mineralization of an oil-water emulsion.

PubMed

Tony, Maha A; Zhao, Y Q; Purcell, P J; El-Sherbiny, M F

2009-04-01

In the present study, homogenous (photo-Fenton) and heterogeneous photo-assisted systems (Fenton/TiO(2)/UV, Fenton/ZnO/UV and Fenton/TiO(2)/UV/Air) were investigated for the treatment of a diesel-oil wastewater emulsion. The augmentation of the photo-Fenton process by heterogeneous TiO(2) increased the reaction rate, in terms of COD reduction efficiency from 61% to 71%. Furthermore, the COD removal efficiency was increased to 84% when air was bubbled through the reactants. However, if the Fenton/TiO(2) /UV/Air process is to be utilized as a treatment for this wastewater, the separation of the TiO(2) from the treated effluent would need further consideration.

Performance of denitrifying microbial fuel cell subjected to variation in pH, COD concentration and external resistance.

PubMed

Li, Jin-Tao; Zhang, Shao-Hui; Hua, Yu-Mei

2013-01-01

The effects of pH, chemical oxygen demand (COD) concentration and external resistance on denitrifying microbial fuel cell were evaluated in terms of electricity generation characteristics and pollutant removal performance. The results showed that anodic influent with weakly alkaline or neutral pH and cathodic influent with weakly acidic pH favored pollutant removal and electricity generation. The suitable influent pH of the anode and cathode were found to be 7.5-8.0 and 6.0-6.5, respectively. In the presence of sufficient nitrate in the cathode, higher influent COD concentration led to more electricity generation and greater pollutant removal rates. With an anodic influent pH of 8.0 and a cathodic influent pH of 6.0, an influent COD concentration of 400 mg/L was deemed to be appropriate. Low external resistance favored nitrate and COD removal. The results suggest that operation of denitrifying microbial fuel cell at a lower external resistance would be desirable for pollutant removal but not electricity generation.

Evaluation of humic substances removal from leachates originating from solid waste landfills in Rio de Janeiro State, Brazil.

PubMed

Lima, Letícia S M S; De Almeida, Ronei; Quintaes, Bianca R; Bila, Daniele M; Campos, Juacyara C

2017-07-29

This study aimed to evaluate the use of coagulation/flocculation and Fenton processes for the removal of the recalcitrant component, in particular humic substances, from two different leachates generated in the Gericinó and Gramacho landfills in Rio de Janeiro State (Brazil). A coagulation/flocculation process, using FeCl 3 ·6H 2 O as the coagulant, was applied to the two leachate samples. In the case of the leachate from Gericinó landfill, the treatment removed 93% of color, 71% of TOC, 69% of COD, 76% of HS, 73% of humic acids (HA) and 82% of fulvic acids (FA). In addition, there was a 75% reduction in the absorbance at 254 nm, using 3,000 mg L -1 of coagulant. In the case of the leachate from Gramacho landfill, the treatment removed 91% of color, 69% of TOC, 68% of COD, 77% of HS, 75% of HA and 80% of FA. In addition, there was a 70% reduction in the absorbance at 254 nm using the same concentration of coagulant (3,000 mg L -1 ). The Fenton processes, using FeSO 4 ·7H 2 O and H 2 O 2 in a ratio of 1:5, were also applied to the two leachate samples. In the case of the Gericinó leachate, the Fenton treatment removed 95% of color, 75% of TOC, 68% of COD, 82% of HS, 77% of HA and 93% of FA. In addition, there was a 93% reduction in the absorbance at 254 nm. In the case of the Gramacho leachate, the Fenton treatment removed 93% of color, 73% of TOC, 71% of COD, 81% of HS, 76% of HA, 90% of FA, and there was an 84% reduction in the absorbance at 254 nm. The results of humic substances, color, organic matter and aromatic organic matter (absorbance at 254 nm) demonstrate that the coagulation/flocculation and Fenton processes were efficient in the removal of recalcitrant organic matter from landfill leachates.

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Elmitwalli, Tarek A; Otterpohl, Ralf

2007-03-01

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).

Activated carbon fiber felt and polymer fiber as biofilm carrier in a modified University of Cape Town process for sewage treatment.

PubMed

Zhou, Dongkai

2013-01-01

Biofilms on fiber-based carriers have attracted much concern in wastewater treatment processes recently. In this study: (1) a novel sandwich structure fiber-based biofilm carrier was produced, which consisted of an inner core composed of polyacrylonitrile-based activated carbon fiber felt (PAN-ACFF) and an outer coat made of polyester reticular cloth with polypropylene fiber loops; (2) the novel carrier was filled in a step-feeding pilot-scale modified University of Cape Town process (MUCT) for sewage treatment; the MUCT contained a series of pre-anoxic/anaerobic/anoxic-1/anoxic-2/oxic tanks, wherein nitrification liquor was recycled to the anoxic-2 tank and an extra liquor return from the anoxic-1 to the pre-anoxic tank was set up; and (3) the removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were continuously tested for two periods as operational parameters alternated. The optimum values were collected in Period II, when the influent loads were 2,100.6 ± 120.3 gCOD/(d m(3)), 205.5 ± 20.4 gTN/(d m(3)), 39.9 ± 3.9 gTP/(d m(3)), the removal percentages were 93.1 ± 1.1% of COD, 39.4 ± 3.5% of TN, and 84.6 ± 3.4% of TP. For COD, NH4(+)-N, and TP, the specific removal loads of filler were 291.5 ± 18.2, 22.9 ± 3.1, 4.8 ± 0.5 (g d)/kg.

High current densities enable exoelectrogens to outcompete aerobic heterotrophs for substrate.

PubMed

Ren, Lijiao; Zhang, Xiaoyuan; He, Weihua; Logan, Bruce E

2014-11-01

In mixed-culture microbial fuel cells (MFCs), exoelectrogens and other microorganisms compete for substrate. It has previously been assumed that substrate losses to other terminal electron acceptors over a fed-batch cycle, such as dissolved oxygen, are constant. However, a constant rate of substrate loss would only explain small increases in coulombic efficiencies (CEs, the fraction of substrate recovered as electrical current) with shorter cycle times, but not the large increases in CE that are usually observed with higher current densities and reduced cycle times. To better understand changes in CEs, COD concentrations were measured over time in fed-batch, single-chamber, air-cathode MFCs at different current densities (external resistances). COD degradation rates were all found to be first-order with respect to COD concentration, even under open circuit conditions with no current generation (first-order rate constant of 0.14 ± 0.01 h(-1) ). The rate of COD removal increased when there was current generation, with the highest rate constant (0.33 ± 0.02 h(-1) ) obtained at the lowest external resistance (100 Ω). Therefore, as the substrate concentration was reduced more quickly due to current generation, the rate of loss of substrate to non-exoelectrogens decreased due to this first-order substrate-concentration dependence. As a result, coulombic efficiencies rapidly increased due to decreased, and not constant, removal rates of substrate by non-exoelectrogens. These results show that higher current densities (lower resistances) redirect a greater percentage of substrate into current generation, enabling large increase in CEs with increased current densities. Biotechnol. Bioeng. 2014;111: 2163-2169. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

Influence of organic loading rate on integrated bioreactor treating hypersaline mustard wastewater.

PubMed

Kang, Wei; Chai, Hongxiang; Yang, Shiwei; Du, Guojun; Zhou, Jian; He, Qiang

2016-07-01

Mustard tuber wastewater is characterized by high salinity and high organic content that is potentially detrimental to the biological treatment system and affects the treatment efficiency accordingly. The experiment used the integrated bioreactor to reduce much of the organics in mustard tuber wastewater, and found the influence of organic loading rate on effluent chemical oxygen demand (COD) and phosphate (PO4 (3-) -P). Results showed that under the condition of 10-15 °C, 6 mg/L of dissolved oxygen, the reduction value of COD removal rate in anaerobic and aerobic area was 14.5% and 31.7% when the organic loading rate increased from 2.0 to 4.0 kg COD/m(3) /day. Therefore, an integrated bioreactor should take 2.0 kg COD/m(3) /day organic loading rate in mustard wastewater treatment if the effluent is expected to meet the third level of "Integrated Wastewater Discharge Standard" (GB 8978-1996). © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Characteristics of sludge developed under different loading conditions during UASB reactor start-up and granulation.

PubMed

Ghangrekar, M M; Asolekar, S R; Joshi, S G

2005-03-01

Sludge characteristics available inside the reactor are of vital importance to maximize advantages of UASB reactor. The organic loading rate and sludge loading rate applied during start-up are among the important parameters to govern the sludge characteristics. Effects of these loading rates on the characteristics of the sludge developed are evaluated in six laboratory scale UASB reactors. The sludge characteristics considered are VSS/SS ratio of the sludge, sludge volume index, specific gravity, settling velocity and metal contents of the sludge developed under different loading rates. The experimental results indicate that, for developing good characteristics sludge, during primary start-up from flocculent inoculum sludge, organic loading rate and sludge loading rate should be in the range of 2.0-4.5 kg COD/m3 d and 0.1-0.25 kg COD/kg VSS d, respectively (chemical oxygen demand, COD). Proper sludge granulation and higher COD removal efficiency will be achieved by these loading rates.

First-order hydrothermal oxidation kinetics of digested sludge compared with raw sludge.

PubMed

Shanableh, A; Imteaz, M

2008-09-01

This article presents an assessment of the first-order hydrothermal oxidation kinetics of a selected digested sludge at subcritical (< 374 degrees C) and supercritical (> 374 degrees C) temperatures in the range of 250-460 degrees C. Furthermore, the results were compared with reported oxidation kinetics of raw sludge treated under identical experimental conditions. In the assessment, oxidation was considered to proceed in two steps: (1) decomposition of the particulate, or non-filterable, chemical oxygen demand (PCOD); followed by (2) ultimate oxidation and removal of the total, particulate and soluble, COD. The accumulation and removal of soluble COD (SCOD) was determined from the difference between the rates of sludge decomposition and ultimate oxidation. Using results from batch and continuous-flow hydrothermal treatment experiments, the reacting organic ingredients were separated into groups according to the ease or difficulty at which they were decomposed or removed, with Arrhenius-type activation energy levels assigned to the different groups. The analysis confirmed that within the treatment range of 75% to more than 97% COD removal, the oxidation kinetics of the digested and raw sludges were nearly identical despite differences in the proportions of their original organic ingredients. The original organic ingredients were mostly removed above 75% COD removal, and the oxidation kinetics appeared to be dominated by the removal of acetic acid, an intermediate by-product which constituted 50% to more than 80% of the remaining COD. Furthermore, the oxidation kinetics of both sludge types were consistent with reported first-order oxidation kinetics of pure acetic acid solutions. The resulting kinetic models adequately represented hydrothermal oxidation of digested sludge, in terms of COD and PCOD removals, as well as accumulation and removal of the soluble SCOD.

[Phosphorus removal characteristics by aerobic granules in normal molasses wastewater after anaerobic treatment].

PubMed

Wang, Shuo; Yu, Shui-Li; Shi, Wen-Xin; Bao, Rui-Ling; Yi, Xue-Song; Li, Jian-Zheng

2012-04-01

COD decreased obviously in normal molasses wastewater after anaerobic treatment, however, concentrations of nitrogen and phosphorus were still higher in the effluent which seriously damaged the ecological balance. In this study, aerobic granules cultivated in sequencing batch airlift reactor (SBAR) were carried out for treating the effluent; phosphorus removal processes and characteristics were discussed as well. The mean diameter of aerobic granules cultivated by multiple carbon sources (acetate, propionate and butyrate) was 1.7 mm. The average phosphorus removal efficiency was 90.9% and the level of phosphorus in effluent was only 1.3 mg x L(-1); TP released per COD consumed was 0.571 and the specific rate of TP released was 5.73 mg x (g x h)(-1). NO3(-) -N usage of phosphorus accumulating organisms (PAOs) improved during denitrifying process because the concentration of propionate and butyrate increased in multiple carbon sources which means the phosphorus uptake efficiency increased when per NO3(-) -N consumed. Phosphorus content represented a stronger correlation with magnesium, calcium and ferrum contents in aerobic granules and their extracellular polymeric substances (EPS), the phosphorus adsorption by EPS could enhance phosphorus removal. 61.9% of phosphorus accumulating organisms were denitrifying phosphorus accumulating organisms in aerobic granules and TP uptake per NO3(-) -N consumed was 1.14 which was higher than that of aerobic granules only cultivated by acetate.

Combined membrane bioreactor (MBR) and reverse osmosis (RO) system for thin-film transistor-liquid crystal display TFT-LCD, industrial wastewater recycling.

PubMed

Chen, T K; Chen, J N

2004-01-01

In TFT-LCD industry, water plays a variety of roles as a cleaning agent and reaction solvent. As good quality water is increasingly a scarce resource and wastewater treatment costs rises, the once-through use of industrial water is becoming uneconomical and environmentally unacceptable. Instead, recycling of TFT-LCD industrial wastewater is become more attractive from both an economic and environmental perspective. This research is mainly to explore the capacity of TFT-LCD industrial wastewater recycling by the process combined with membrane bioreactor and reverse osmosis processes. Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 97.3%. For TOC and BOD5 items, the average removal efficiencies were 97.8 and 99.4% respectively. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of the UF membrane device incorporated with biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After treatment of RO, excellent water quality of permeate were under 5 mg/l, 2.5 mg/l and 150 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled for the cooling tower make-up water or other purposes.

The effect of primary sedimentation on full-scale WWTP nutrient removal performance.

PubMed

Puig, S; van Loosdrecht, M C M; Flameling, A G; Colprim, J; Meijer, S C F

2010-06-01

Traditionally, the performance of full-scale wastewater treatment plants (WWTPs) is measured based on influent and/or effluent and waste sludge flows and concentrations. Full-scale WWTP data typically have a high variance which often contains (large) measurement errors. A good process engineering evaluation of the WWTP performance is therefore difficult. This also makes it usually difficult to evaluate effect of process changes in a plant or compare plants to each other. In this paper we used a case study of a full-scale nutrient removing WWTP. The plant normally uses presettled wastewater, as a means to increase the nutrient removal the plant was operated for a period by-passing raw wastewater (27% of the influent flow). The effect of raw wastewater addition has been evaluated by different approaches: (i) influent characteristics, (ii) design retrofit, (iii) effluent quality, (iv) removal efficiencies, (v) activated sludge characteristics, (vi) microbial activity tests and FISH analysis and, (vii) performance assessment based on mass balance evaluation. This paper demonstrates that mass balance evaluation approach helps the WWTP engineers to distinguish and quantify between different strategies, where others could not. In the studied case, by-passing raw wastewater (27% of the influent flow) directly to the biological reactor did not improve the effluent quality and the nutrient removal efficiency of the WWTP. The increase of the influent C/N and C/P ratios was associated to particulate compounds with low COD/VSS ratio and a high non-biodegradable COD fraction. Copyright 2010 Elsevier Ltd. All rights reserved.

Unraveling the influence of the COD/sulfate ratio on organic matter removal and methane production from the biodigestion of sugarcane vinasse.

PubMed

Kiyuna, Luma Sayuri Mazine; Fuess, Lucas Tadeu; Zaiat, Marcelo

2017-05-01

Throughout the sugarcane harvest, it is common for sulfate to accumulate in the vinasse of sugar and ethanol plants. However, little is known regarding the influence of sulfate on the anaerobic digestion (AD) of vinasse, which may lead to severe performance losses. This study assessed the influence of various COD/sulfate ratios (12.0, 10.0 and 7.5) on both COD removal and methane (CH 4 ) production from sugarcane vinasse AD. Batch assays were conducted in thermophilic conditions. At a COD/sulfate ratio of 7.5, CH 4 production was 35% lower compared with a ratio of 12.0, considering a diversion of approximately 13.6% of the electron flow to sulfidogenesis. The diversion of electrons to sulfidogenesis was negligible at COD/sulfate ratios higher than 25, considering the exponential increase in CH 4 production. Organic matter degradation was not greatly affected by sulfidogenesis, with COD removal levels higher than 80%, regardless of the initial COD/sulfate ratio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of submerged anaerobic membrane bioreactor (SAMBR) containing powdered activated carbon (PAC) for the treatment of textile effluents.

PubMed

Baêta, B E L; Ramos, R L; Lima, D R S; Aquino, S F

2012-01-01

This work investigated the use of submerged anaerobic membrane bioreactors (SAMBRs) in the presence and absence of powdered activated carbon (PAC) for the treatment of genuine textile wastewater. The reactors were operated at 35 °C with an HRT of 24 h and the textile effluent was diluted (1:10) with nutrient solution containing yeast extract as the source of the redox mediation riboflavin. The results showed that although both SAMBRs exhibited an excellent performance, the presence of PAC inside SAMBR-1 enhanced reactor stability and removal efficiency of chemical oxygen demand (COD), volatile fatty acids (VFA), turbidity and color. The median removal efficiencies of COD and color in SAMBR-1 were, 90 and 94% respectively; whereas for SAMBR-2 (without PAC) these values were 79 and 86%, In addition, the median values of turbidity and VFA were 8 NTU and 8 mg/L for SAMBR-1 and 14 NTU and 26 mg/L for SAMBR-2, indicating that the presence of PAC inside SAMBR-1 led to the production of an anaerobic effluent of high quality regarding such parameters.

Electricity generation and brewery wastewater treatment from sequential anode-cathode microbial fuel cell.

PubMed

Wen, Qing; Wu, Ying; Zhao, Li-xin; Sun, Qian; Kong, Fan-ying

2010-02-01

A sequential anode-cathode double-chamber microbial fuel cell (MFC), in which the effluent of anode chamber was used as a continuous feed for an aerated cathode chamber, was constructed in this experiment to investigate the performance of brewery wastewater treatment in conjugation with electricity generation. Carbon fiber was used as anode and plain carbon felt with biofilm as cathode. When hydraulic retention time (HRT) was 14.7 h, a relatively high chemical oxygen demand (COD) removal efficiency of 91.7%-95.7% was achieved under long-term stable operation. The MFC displayed an open circuit voltage of 0.434 V and a maximum power density of 830 mW/m(3) at an external resistance of 300 Omega. To estimate the electrochemical performance of the MFC, electrochemical measurements were carried out and showed that polarization resistance of anode was the major limiting factor in the MFC. Since a high COD removal efficiency was achieved, we conclude that the sequential anode-cathode MFC constructed with bio-cathode in this experiment could provide a new approach for brewery wastewater treatment.

Impact of mild alkali dosage on immobilized Exiguobacterium spp. mediated cost and energy efficient sludge disintegration.

PubMed

Rajesh Banu, J; Ushani, U; Rajkumar, M; Naresh Kumar, R; Parthiba Karthikeyan, O

2017-12-01

Approaches to (extracellular polymeric substance) EPS removal were studied with major aim to enhance the biodegradability and sludge solubilization. In this study, a novel approach of entrapment of bacterial strain was carried out to achieve long term activity of protease secreting bacteria Exiguobacterium sp. A mild treatment of potassium hydroxide (KOH) was applied to remove EPS which was followed by entrapment under the biological pretreatment. The efficiency of Exiguobacterium was predicted through dissolvable organic and suspended solids (SS) reduction. The maximum dissolvable organic matter released was 2300mg/L with the solubilization of 23% which was obtained for sludge without EPS (SWOE). For dissolvable organic release, SWOE showed higher final methane production of 232mL/g COD at the production rate of 16.2mL/g COD.d. The SWOE pretreatment was found to be cost effective and less energy intensive beneficial in terms of energy and cost (43.9KWh and -8.2USD) when compared to sludge with EPS (SWE) pretreatment (-177.6KWh and -91.23USD). Copyright © 2017 Elsevier Ltd. All rights reserved.

Electricity generation and brewery wastewater treatment from sequential anode-cathode microbial fuel cell*

PubMed Central

Wen, Qing; Wu, Ying; Zhao, Li-xin; Sun, Qian; Kong, Fan-ying

2010-01-01

A sequential anode-cathode double-chamber microbial fuel cell (MFC), in which the effluent of anode chamber was used as a continuous feed for an aerated cathode chamber, was constructed in this experiment to investigate the performance of brewery wastewater treatment in conjugation with electricity generation. Carbon fiber was used as anode and plain carbon felt with biofilm as cathode. When hydraulic retention time (HRT) was 14.7 h, a relatively high chemical oxygen demand (COD) removal efficiency of 91.7%–95.7% was achieved under long-term stable operation. The MFC displayed an open circuit voltage of 0.434 V and a maximum power density of 830 mW/m3 at an external resistance of 300 Ω. To estimate the electrochemical performance of the MFC, electrochemical measurements were carried out and showed that polarization resistance of anode was the major limiting factor in the MFC. Since a high COD removal efficiency was achieved, we conclude that the sequential anode-cathode MFC constructed with bio-cathode in this experiment could provide a new approach for brewery wastewater treatment. PMID:20104642

Effect of water depth on the removal of organic matter in horizontal subsurface flow constructed wetlands.

PubMed

Aguirre, Paula; Ojeda, Esther; García, Joan; Barragán, Jesús; Mujeriego, Rafael

2005-01-01

The objective of this article is to evaluate the effect of water depth on organic matter removal efficiency in horizontal subsurface flow constructed wetlands (SSFs). Experiments were carried out in a pilot plant comprising eight parallel SSF of almost equal surface area (54-56 m2 each) and treating urban wastewater. Each SSF differs from the others in the aspect ratio or the size of the granular medium or the water depth. During a period of two years, the shallow SSFs (0.27 m water depth) removed more chemical oxygen demand (COD) (72-81%), biochemical oxygen demand (BOD)5 (72-85%), ammonia (35-56%), and dissolved reactive phosphorus (DRP) (8-23%) than deep SSFs (0.5 m water depth) (59-64% for COD; 51-57% for BOD5; 18-29% for ammonia; and 0-7% for DRP). Experiments carried out during the summer indicated that sulphate reduction accounted for a clearly higher organic matter removal in the deep SSFs than in the shallow ones. Denitrification seemed to be a significant mechanism for organic matter removal to occur in shallow SSFs. The results suggest that the relative contribution of different metabolic pathways varies with depth.

Anaerobic on-site treatment of black water and dairy parlour wastewater in UASB-septic tanks at low temperatures.

PubMed

Luostarinen, Sari A; Rintala, Jukka A

2005-01-01

Anaerobic on-site treatment of synthetic black water (BW) and dairy parlour wastewater (DPWW) was studied in two-phased upflow anaerobic sludge blanket (UASB)-septic tanks at low temperatures (10-20 degrees C). At all temperatures, total chemical oxygen demand (COD(t)) removal was above 90% with BW and above 80% with DPWW and removal of total suspended solids (TSS) above 90% with both wastewaters. Moreover, dissolved COD (COD(dis)) removal was approx. 70% with both wastewaters indicating good biological activity of the sludges. With BW, a single-phased reactor was found sufficient for good COD removals, while with DPWW, a two-phased process was required. Temperature optimum of reactor sludges was still 35 degrees C after long (398d) operation. Most of the nutrients from BW were removed with TSS, while with DPWW nutrient removal was low. In conclusion, UASB-septic tank was found feasible for (pre)treatment of BW and DPWW at low temperatures.

Controlling the COD removal of an A-stage pilot study with instrumentation and automatic process control.

PubMed

Miller, Mark W; Elliott, Matt; DeArmond, Jon; Kinyua, Maureen; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

2017-06-01

The pursuit of fully autotrophic nitrogen removal via the anaerobic ammonium oxidation (anammox) pathway has led to an increased interest in carbon removal technologies, particularly the A-stage of the adsorption/bio-oxidation (A/B) process. The high-rate operation of the A-stage and lack of automatic process control often results in wide variations of chemical oxygen demand (COD) removal that can ultimately impact nitrogen removal in the downstream B-stage process. This study evaluated the use dissolved oxygen (DO) and mixed liquor suspended solids (MLSS) based automatic control strategies through the use of in situ on-line sensors in the A-stage of an A/B pilot study. The objective of using these control strategies was to reduce the variability of COD removal by the A-stage and thus the variability of the effluent C/N. The use of cascade DO control in the A-stage did not impact COD removal at the conditions tested in this study, likely because the bulk DO concentration (>0.5 mg/L) was maintained above the half saturation coefficient of heterotrophic organisms for DO. MLSS-based solids retention time (SRT) control, where MLSS was used as a surrogate for SRT, did not significantly reduce the effluent C/N variability but it was able to reduce COD removal variation in the A-stage by 90%.

Some properties of a granular activated carbon-sequencing batch reactor (GAC-SBR) system for treatment of textile wastewater containing direct dyes.

PubMed

Sirianuntapiboon, Suntud; Sadahiro, Ohmomo; Salee, Paneeta

2007-10-01

Resting (living) bio-sludge from a domestic wastewater treatment plant was used as an adsorbent of both direct dyes and organic matter in a sequencing batch reactor (SBR) system. The dye adsorption capacity of the bio-sludge was not increased by acclimatization with direct dyes. The adsorption of Direct Red 23 and Direct Blue 201 onto the bio-sludge was almost the same. The resting bio-sludge showed higher adsorption capacity than the autoclaved bio-sludge. The resting bio-sludge that was acclimatized with synthetic textile wastewater (STWW) without direct dyes showed the highest Direct Blue 201, COD, and BOD(5) removal capacities of 16.1+/-0.4, 453+/-7, and 293+/-9 mg/g of bio-sludge, respectively. After reuse, the dye adsorption ability of deteriorated bio-sludge was recovered by washing with 0.1% sodium dodecyl sulfate (SDS) solution. The direct dyes in the STWW were also easily removed by a GAC-SBR system. The dye removal efficiencies were higher than 80%, even when the system was operated under a high organic loading of 0.36kgBOD(5)/m(3)-d. The GAC-SBR system, however, showed a low direct dye removal efficiency of only 57+/-2.1% with raw textile wastewater (TWW) even though the system was operated with an organic loading of only 0.083kgBOD(5)/m(3)-d. The dyes, COD, BOD(5), and total kjeldalh nitrogen removal efficiencies increased up to 76.0+/-2.8%, 86.2+/-0.5%, 84.2+/-0.7%, and 68.2+/-2.1%, respectively, when 0.89 g/L glucose (organic loading of 0.17kgBOD(5)/m(3)-d) was supplemented into the TWW.

Impact of leachate composition on the advanced oxidation treatment.

PubMed

Oulego, Paula; Collado, Sergio; Laca, Adriana; Díaz, Mario

2016-01-01

Advanced oxidation processes (AOPs) are gaining importance as an alternative to the biological or physicochemical treatments for the management of leachates. In this work, it has been studied the effect of the characteristics of the leachate (content in humic acids, landfill age and degree of stabilization) on the wet oxidation process and final quality of the treated effluent. A high concentration of humic acids in the leachate had a positive effect on the COD removal because this fraction is more easily oxidizable. Additionally, it has been demonstrated that the simultaneous presence of humic acid and the intermediates generated during the oxidation process improved the degradation of this acid, since such intermediates are stronger initiators of free radicals than the humic acid itself. Similar values of COD removals (49% and 51%) and biodegradability indices (0.30 and 0.35) were observed, after 8 h of wet oxidation, for the stabilised leachate (biologically pretreated) and the raw one, respectively. Nevertheless, final colour removal was much higher for the stabilised leachate, achieving values up to 91%, whereas for the raw one only 56% removal was attained for the same reaction time. Besides, wet oxidation treatment was more efficient for the young leachate than for the old one, with final COD conversions of 60% and 37%, respectively. Eventually, a triangular "three-lump" kinetic model, which considered direct oxidation to CO2 and partial oxidation through intermediate compounds, was here proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Visible light photocatalytic disintegration of waste activated sludge for enhancing biogas production.

PubMed

Anjum, Muzammil; Al-Talhi, Hasan A; Mohamed, Saleh A; Kumar, Rajeev; Barakat, M A

2018-06-15

Biogas production using waste activated sludge (WAS) is one of the most demanding technologies for sludge treatment and generating energy in sustainable manner. The present study deals with the photocatalytic pretreatment of WAS using ZnO-ZnS@polyaniline (ZnO-ZnS@PANI) nanocomposite as means for increasing its degradability for improved biogas production by anaerobic digestion (AD). Photocatalysis accelerated the hydrolysis of WAS and increased the sCOD by 6.7 folds after 6 h and transform tCOD into bioavailable sCOD. After the AD of WAS, a removal of organic matter (60.6%) and tCOD (69.3%) was achieved in photocatalytic pretreated sludge. The biogas production was 1.6 folds higher in photocatalytic sludge with accumulative biogas up to 1645.1 ml L -1 vs after 45 days compared with the raw sludge (1022.4 ml L -1 VS ). Moreover, the photocatalysis decrease the onset of methanogenesis from 25 to 12 days while achieve the maximum conversion rate of reducing sugars into organic acids at that time. These results suggested that photocatalysis is an efficient pretreatment method and ZnO-ZnS@PANI can degrade sludge efficiently for enhance biogas production in anaerobic digestion process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nutrient removal and biogas upgrading by integrating freshwater algae cultivation with piggery anaerobic digestate liquid treatment.

PubMed

Xu, Jie; Zhao, Yongjun; Zhao, Guohua; Zhang, Hui

2015-08-01

An integrated approach that combined freshwater microalgae Scenedesmus obliquus (FACHB-31) cultivation with piggery anaerobic digestate liquid treatment was investigated in this study. The characteristics of algal growth, biogas production, and nutrient removal were examined using photobioreactor bags (PBRbs) to cultivate S. obliquus (FACHB-31) in digestate with various digestate dilutions (the concentration levels of 3200, 2200, 1600, 1200, 800, and 400 mg L(-1) chemical oxygen demand (COD)) during 7-day period. The effects of the level of pollutants on nutrient removal efficiency and CO2 removal process were investigated to select the optimum system for effectively upgrade biogas and simultaneously reduce the nutrient content in digestate. The treatment performance displayed that average removal rates of COD, total nitrogen (TN), total phosphorous (TP), and CO2 were 61.58-75.29, 58.39-74.63, 70.09-88.79, and 54.26-73.81 %, respectively. All the strains grew well under any the dilution treatments. With increased initial nutrient concentration to a certain range, the CO4 content (v/v) of raw biogas increased. Differences in the biogas enrichment of S. obliquus (FACHB-31) in all treatments mainly resulted from variations in biomass productivity and CO2 uptake. Notably, the diluted digestate sample of 1600 mg L(-1) COD provided an optimal nutrient concentration for S. obliquus (FACHB-31) cultivation, where the advantageous nutrient and CO2 removals, as well as the highest productivities of biomass and biogas upgrading, were revealed. Results showed that microalgal biomass production offered real opportunities to address issues such as CO2 sequestration, wastewater treatment, and biogas production.

Performance of sequential anaerobic/aerobic digestion applied to municipal sewage sludge.

PubMed

Tomei, M Concetta; Rita, Sara; Mininni, Giuseppe

2011-07-01

A promising alternative to conventional single phase processing, the use of sequential anaerobic-aerobic digestion, was extensively investigated on municipal sewage sludge from a full scale wastewater treatment plant. The objective of the work was to evaluate sequential digestion performance by testing the characteristics of the digested sludge in terms of volatile solids (VS), Chemical Oxygen Demand (COD) and nitrogen reduction, biogas production, dewaterability and the content of proteins and polysaccharides. VS removal efficiencies of 32% in the anaerobic phase and 17% in the aerobic one were obtained, and similar COD removal efficiencies (29% anaerobic and 21% aerobic) were also observed. The aerobic stage was also efficient in nitrogen removal providing a decrease of the nitrogen content in the supernatant attributable to nitrification and simultaneous denitrification. Moreover, in the aerobic phase an additional marked removal of proteins and polysaccharides produced in the anaerobic phase was achieved. The sludge dewaterability was evaluated by determining the Optimal Polymer Dose (OPD) and the Capillary Suction Time (CST) and a significant positive effect due to the aerobic stage was observed. Biogas production was close to the upper limit of the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. From a preliminary analysis it was found that the energy demand of the aerobic phase was significantly lower than the recovered energy in the anaerobic phase and the associated additional cost was negligible in comparison to the saving derived from the reduced amount of sludge to be disposed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Study on COD removal mechanism and reaction kinetics of oilfield wastewater.

PubMed

Yin, Xian-Qing; Jing, Bo; Chen, Wen-Juan; Zhang, Jian; Liu, Qian; Chen, Wu

2017-11-01

The chemical oxygen demand (COD) removal mechanism and reaction kinetics were mainly studied in the treatment of oilfield oily sewage containing polymer by three-dimensional electrode reactor. The results proved that the residual active oxides O 3 , H 2 O 2 , •OH and active chlorine in the system of electrochemical reaction could be effectively detected, and the COD removal mechanism was co-oxidation of active oxides; Under these experimental conditions: the electrolysis current of 6 A, surface/volume ratio of 6/25(cm 2 ·L -1 ), the reaction time of 50 min, the COD cr of treated sewage was no more than 50 mg·L -1 ; the removal reaction of COD conformed to apparent second-order reaction kinetic model, the correlation coefficient R 2 was 0.9728, and the apparent reaction rate constant was k = 3.58 × 10 -4 (L·min -1 ·mg -1 ·m -2 ). To reach the goal, the COD cr was no more than 50 mg·L -1 in treated sewage, and the theory minimum processing time was 45.73 min. The verification of experimental results was consistent with kinetic equations.

Anaerobic treatment of landfill leachate by sulfate reduction.

PubMed

Henry, J G; Prasad, D

2000-01-01

The present study was conducted to investigate the effectiveness of the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The effects of several COD/SO4 ratios (keeping COD constant) and loadings on anaerobic filter performance were studied and compared with the results from anaerobic filters which followed the methanogenic pathway. Results indicated that the treatability of leachate by sulphate reducing bacteria (SRB) was dependent upon the leachate strength. With high strength leachate (COD = 15,000 mg/L) from the Keele Valley Landfill, it was found that at lower COD/SO4 ratios (< or = 1.6) toxic conditions developed in the system that were more inhibitory to the SRB than to the methane producing bacteria (MPB). As the COD/SO4 ratio increased, methanogenesis predominated. No predominance of SRB occurred at any COD/SO4 ratio with high strength leachate. The highest COD removal achieved was about 70% of which 20% was accomplished by the SRB at a COD/SO4 ratio of 1.6 and an organic loading rate (OLR) of 4 kg COD/m3.d. With low strength leachate (COD = 1500-3300 mg/L) from the Brock West Landfill, and a COD/SO4 ratio < or = 1, SRB became predominant. In these anaerobic filters in which SRB were predominant, the SRB reduced the COD as well as the MPB could. Sulphide inhibition did not take place at any loading in units treating low strength leachate. Consequently, both SRB and MPB should function at COD/SO4 ratios between 1 and 3. About 60% COD removal was achieved at a loading of 2.8 kg COD/m3.d and a COD/SO4 ratio of 1.0. However at a loading of 6 kg COD/m3.d only 27% COD removal was achieved, all of it through the sulphate-reduction pathway. These OLR values are comparable to those applied in systems where methanogenesis was dominant. It was also observed that once the methanogens were established in the units, it was not possible to displace them completely. However, where methanogenesis had not been previously established, it was found that sulphate-reduction could be the sole pathway for COD removal. From this study, it can be concluded that there is no advantage to the sulphate-reduction pathway in the anaerobic treatment of landfill leachate. The other options for increasing the loadings, i.e. the use of high surface/volume filter media (to achieve higher biomass concentrations) or high rate systems are likely to be more successful.

Inhibitory effect of high NH{sub 4}{sup +}–N concentration on anaerobic biotreatment of fresh leachate from a municipal solid waste incineration plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zhao; Dang, Yan; Li, Caihua

2015-09-15

Highlights: • High NH{sub 4}{sup +}–N concentrations inhibit anaerobic treatment of leachate. • Inhibitory effect of NH{sub 4}{sup +}–N concentrations on anaerobic granular sludge is reversible. • High NH{sub 4}{sup +}–N concentrations inhibit bioactivities of microorganisms instead of survival. - Abstract: Fresh leachate from municipal solid waste (MSW) incineration plants generally contains extremely high NH{sub 4}{sup +}–N concentration which could inhibit the bioactivity of microorganisms. The inhibitory effect of high NH{sub 4}{sup +}–N concentration on anaerobic biotreatment of fresh leachate from a MSW incineration plant in China has been investigated in this study. The inhibition processes was studied by bothmore » static tests and a laboratory-scale expanded granular sludge bed (EGSB) reactor. The specific methanogenic activity (SMA) of the microorganisms in anaerobic granular sludge was inhibited with the NH{sub 4}{sup +}–N concentration increasing to 1000 mg/L in static tests. As well the chemical oxygen demand (COD) removal efficiency and the methane yield decreased in the EGSB reactor, while the volatile fatty acids (VFAs) accumulated and extracellular polymeric substances (EPS) of the anaerobic granular sludge increased with NH{sub 4}{sup +}–N concentration rising to 1000 mg/L, without any rebounding during 30 days of operation. Decreasing NH{sub 4}{sup +}–N concentration to 500 mg/L in influent, the COD removal efficiency recovered to about 85% after 26 days. 1000 mg/L of NH{sub 4}{sup +}–N in leachate was suggested to be the inhibition threshold in EGSB reactor. High-throughput sequencing results showed little changes in microbial communities of the sludge for a high NH{sub 4}{sup +}–N concentration, indicating that the survival of most microorganisms was not affected under such a condition. It inhibited the bioactivity of the microorganisms, resulting in decrease of the COD removal efficiency.« less

Re-use of winery wastewaters for biological nutrient removal.

PubMed

Rodríguez, L; Villaseñor, J; Buendía, I M; Fernández, F J

2007-01-01

The aim of this study was to evaluate the feasibility of the re-use of the winery wastewater to enhance the biological nutrient removal (BNR) process. In batch experiments it was observed that the addition of winery wastewater mainly enhanced the nitrogen removal process because of the high denitrification potential (DNP), of about 130 mg N/g COD, of the contained substrates. This value is very similar to that obtained by using pure organic substrates such as acetate. The addition of winery wastewater did not significantly affect either phosphorus or COD removal processes. Based on the experimental results obtained, the optimum dosage to remove each mg of N-NO3 was determined, being a value of 6.7 mg COD/mg N-NO3. Because of the good properties of the winery wastewater to enhance the nitrogen removal, the viability of its continuous addition in an activated sludge pilot-scale plant for BNR was studied. Dosing the winery wastewater to the pilot plant a significant increase in the nitrogen removal was detected, from 58 to 75%. The COD removal was slightly increased, from 89 to 95%, and the phosphorus removal remained constant.

Electrooxidation of industrial wastewater containing 1,4-dioxane in the presence of different salts.

PubMed

Barndõk, H; Hermosilla, D; Cortijo, L; Torres, E; Blanco, A

2014-04-01

The treatment of 1,4-dioxane solution by electrochemical oxidation on boron-doped diamond was studied using a central composite design and the response surface methodology to investigate the use of SO4 (2-) and HCO3 (-) as supporting electrolytes considering the applied electric current, initial chemical oxygen demand (COD) value, and treatment time. Two industrial effluents containing bicarbonate alkalinity, one just carrying 1,4-dioxane (S1), and another one including 1,4-dioxane and 2-methyl-1,3-dioxolane (S2), were treated under optimized conditions and subsequently subjected to biodegradability assays with a Pseudomonas putida culture. Electrooxidation was compared with ozone oxidation (O3) and its combination with hydrogen peroxide (O3/H2O2). Regarding the experimental design, the optimal compromise for maximum COD removal at minimum energy consumption was shown at the maximum tested concentrations of SO4 (2-) and HCO3 (-) (41.6 and 32.8 mEq L(-1), respectively) and the maximum selected initial COD (750 mg L(-1)), applying a current density of 11.9 mA cm(-2) for 3.8 h. Up to 98 % of the COD was removed in the electrooxidation treatment of S1 effluent using 114 kWh per kg of removed COD and about 91 % of the COD from S2 wastewater applying 49 kWh per kg of removed COD. The optimal biodegradability enhancement was achieved after 1 h of electrooxidation treatment. In comparison with O3 and O3/H2O2 alternatives, electrochemical oxidation achieved the fastest degradation rate per oxidant consumption unit, and it also resulted to be the most economical treatment in terms of energy consumption and price per unit of removed COD.

Influence of powdered activated carbon addition on water quality, sludge properties, and microbial characteristics in the biological treatment of commingled industrial wastewater.

PubMed

Hu, Qing-Yuan; Li, Meng; Wang, Can; Ji, Min

2015-09-15

A powdered activated carbon-activated sludge (PAC-AS) system, a traditional activated sludge (AS) system, and a powdered activated carbon (PAC) system were operated to examine the insights into the influence of PAC addition on biological treatment. The average COD removal efficiencies of the PAC-AS system (39%) were nearly double that of the AS system (20%). Compared with the average efficiencies of the PAC system (7%), COD removal by biodegradation in the PAC-AS system was remarkably higher than that in the AS system. The analysis of the influence of PAC on water quality and sludge properties showed that PAC facilitated the removal of hydrophobic matter and metabolic acidic products, and also enhanced the biomass accumulation, sludge settleability, and specific oxygen uptake rate inside the biological system. The microbial community structures in the PAC-AS and AS systems were monitored. The results showed that the average well color development in the PAC-AS system was higher than that in the AS system. The utilization of various substrates by microorganisms in the two systems did not differ. The dissimilarity index was far less than one; thus, showing that the microbial community structures of the two systems were the same. Copyright © 2015 Elsevier B.V. All rights reserved.

Performance of the subsurface flow constructed wetlands for pretreatment of slightly polluted source water.

PubMed

Yang, Xu; Zhang, Xueping; Wang, Jifu; Zhao, Guangying; Wang, Baojian

2014-05-01

The slightly polluted source water of Yellow River was pretreated in a horizontal subsurface flow constructed wetland (HSFCW) and a lateral subsurface flow constructed wetland (LSFCW) in the Ji'nan city Reservoir, Shandong, China. During almost one years run, the results showed that at the hydraulic loading rate of 1 m/day, the removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN), ammonium nitrogen (NH4 (+)-N) and total phosphorus (TP) in the HSFCW were 48.9, 51.4, 48.7 and 48.9 %, respectively, and the corresponding removal efficiencies in the LSFCW were 50.51, 53.12, 50.44 and 50.83 %, respectively. The HSFCW and LSFCW had a similar high potential for nutrients removal and LSFCW was slightly better. According to the China standard for surface water resources (GB3838-2002), mean effluent COD can reach the Class I (≤ 15 mg/L), and NH4 (+)-N and TP and TN can reach nearly the Class I (≤ 0.015 mg/L), the Class III (≤ 0.05 mg/L) and the Class IV (≤ 1.5 mg/L), respectively. It can be concluded that the slightly polluted source water from Reservoir was pretreated well by the constructed wetland.

Microbial Community Analysis of Anaerobic Reactors Treating Soft Drink Wastewater

PubMed Central

Narihiro, Takashi; Kim, Na-Kyung; Mei, Ran; Nobu, Masaru K.; Liu, Wen-Tso

2015-01-01

The anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors containing methanogenic microbial consortia were applied to treat synthetic soft drink wastewater, which contains polyethylene glycol (PEG) and fructose as the primary constituents. The AP and HP reactors achieved high COD removal efficiency (>95%) after 80 and 33 days of the operation, respectively, and operated stably over 2 years. 16S rRNA gene pyrotag analyses on a total of 25 biofilm samples generated 98,057 reads, which were clustered into 2,882 operational taxonomic units (OTUs). Both AP and HP communities were predominated by Bacteroidetes, Chloroflexi, Firmicutes, and candidate phylum KSB3 that may degrade organic compound in wastewater treatment processes. Other OTUs related to uncharacterized Geobacter and Spirochaetes clades and candidate phylum GN04 were also detected at high abundance; however, their relationship to wastewater treatment has remained unclear. In particular, KSB3, GN04, Bacteroidetes, and Chloroflexi are consistently associated with the organic loading rate (OLR) increase to 1.5 g COD/L-d. Interestingly, KSB3 and GN04 dramatically decrease in both reactors after further OLR increase to 2.0 g COD/L-d. These results indicate that OLR strongly influences microbial community composition. This suggests that specific uncultivated taxa may take central roles in COD removal from soft drink wastewater depending on OLR. PMID:25748027

Depth treatment of coal-chemical engineering wastewater by a cost-effective sequential heterogeneous Fenton and biodegradation process.

PubMed

Fang, Yili; Yin, Weizhao; Jiang, Yanbin; Ge, Hengjun; Li, Ping; Wu, Jinhua

2018-05-01

In this study, a sequential Fe 0 /H 2 O 2 reaction and biological process was employed as a low-cost depth treatment method to remove recalcitrant compounds from coal-chemical engineering wastewater after regular biological treatment. First of all, a chemical oxygen demand (COD) and color removal efficiency of 66 and 63% was achieved at initial pH of 6.8, 25 mmol L -1 of H 2 O 2 , and 2 g L -1 of Fe 0 in the Fe 0 /H 2 O 2 reaction. According to the gas chromatography-mass spectrometer (GC-MS) and gas chromatography-flame ionization detector (GC-FID) analysis, the recalcitrant compounds were effectively decomposed into short-chain organic acids such as acetic, propionic, and butyric acids. Although these acids were resistant to the Fe 0 /H 2 O 2 reaction, they were effectively eliminated in the sequential air lift reactor (ALR) at a hydraulic retention time (HRT) of 2 h, resulting in a further decrease of COD and color from 120 to 51 mg L -1 and from 70 to 38 times, respectively. A low operational cost of 0.35 $ m -3 was achieved because pH adjustment and iron-containing sludge disposal could be avoided since a total COD and color removal efficiency of 85 and 79% could be achieved at an original pH of 6.8 by the above sequential process with a ferric ion concentration below 0.8 mg L -1 after the Fe 0 /H 2 O 2 reaction. It indicated that the above sequential process is a promising and cost-effective method for the depth treatment of coal-chemical engineering wastewaters to satisfy discharge requirements.

Application and microbial ecology of psychrotrophs in domestic wastewater treatment at low temperature.

PubMed

Xu, Zhenzhen; Ben, Yue; Chen, Zhonglin; Jiang, Anxi; Shen, Jimin; Han, Xiaoyun

2018-01-01

The feasibility of a bunch of screened psychrotrophs being applied to low-temperature wastewater treatment was investigated. The screened psychrophillic strains are capable of growth at a broad temperature-range from 0 to 40 °C and exhibit a preferable TTC-dehydrogenase activity at low temperature (4-10 °C). Along the sharply fluctuant temperatures (25-4-25 °C), the screened psychrotrophs (compared with the indigenous mesophiles) demonstrate less fluctuations of COD removal and more rapid recovery after temperature shocks. COD removal of approximate 80% was recorded by single psychrotrophs (while only 10% by single mesophiles) at low temperature (4 °C). Soft polyurethane foam showed better performance for psychrotrophs immobilization, with the optimal filling rate of 30% (v/v) in the bioreactor. The observation shows that the immobilized psychrotrophs demonstrated a relatively high performance on both conventional and emerging organic contaminants removals at low temperature. In order to check the feasibility of the screened psychrotrophs in treating actual domestic wastewater, a pilot-scale ICABR bioreactor was operated firstly at low temperature (4 °C) and then at seasonal varying temperatures (0-30 °C) for one year, the influent COD of 150-600 mg L -1 was efficiently reduced to 40 ± 18 mg L -1 under the conditions of an overall hydraulic retention time of 10 h. Furthermore, psychrotrophs performed stably as the predominant bacteria family during the whole operation. This study provides evidence that microbial intensification with psychrotrophs was a feasible strategy to improve the efficiency of conventional wastewater treatment process at low temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

A soil infiltration system incorporated with sulfur-utilizing autotrophic denitrification (SISSAD) for domestic wastewater treatment.

PubMed

Kong, Zhe; Feng, Chuanping; Chen, Nan; Tong, Shuang; Zhang, Baogang; Hao, Chunbo; Chen, Kun

2014-05-01

To enhance the denitrification performance of soil infiltration, a soil infiltration system incorporated with sulfur-utilizing autotrophic denitrification (SISSAD) for domestic wastewater treatment was developed, and the SISSAD performance was evaluated using synthetic domestic wastewater in this study. The aerobic respiration and nitrification were mainly taken place in the upper aerobic stage (AES), removed 88.44% COD and 89.99% NH4(+)-N. Moreover, autotrophic denitrification occurred in the bottom anaerobic stage (ANS), using the CO2 produced from AES as inorganic carbon source. Results demonstrated that the SISSAD showed a remarkable performance on COD removal efficiency of 95.09%, 84.86% for NO3(-)-N, 95.25% for NH4(+)-N and 93.15% for TP. This research revealed the developed system exhibits a promising application prospect for domestic wastewater in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterisation of medical-waste sterilisation-plant wastewater and a preliminary study of coagulation-flocculation treatment options.

PubMed

Ozkan, O; Mihçiokur, H; Azgin, S T; Ozdemir, O

2010-01-01

Wastewater from a medical-waste sterilisation plant (MWSP) contains unique pollutants and requires on-site treatment to prevent contamination of the municipal sewage system and receiving water bodies. Therefore, to meet the prescribed discharge standards and comply with the legal regulations, pre-treatment must be applied to MWSP wastewater. In this study, the capabilities of coagulation-flocculation processes were investigated for MWSP wastewater treatment. Processes using ferric chloride, ferrous sulfate and aluminium sulfate as coagulants were characterised. During the coagulation experiments, seven different coagulant dosages and four different pH values were evaluated to determine the optimum coagulant dosage and pH value. The highest removal efficiency of chemical oxygen demand (COD) was obtained using 300 mg/L of ferric chloride at pH 10. A COD removal of about 60% as well as considerable reductions in the amounts of suspended solids, nitrogen and phosphorus were realised.

Influence of sludge reflux ratios on biodegradation performance in a coupled landfill leachate treatment process based on UASB and submerged MBR.

PubMed

Wang, Bing; Li, Wei; Liu, Lei; Huang, Guo He

2016-07-28

This study was undertaken to investigate the effects of different sludge reflux ratios (SRRs) on the overall performance and the fouling behavior of the up-flow anaerobic sludge blanket (UASB) reactor-anoxic-membrane bioreactor (MBR). The leachate and synthetic municipal wastewater were mixed in order to improve the biodegradability of the old leachate. Results showed that excellent removal efficiencies for chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) were obtained by using the integrated UASB-anoxic-MBR process. The average COD removals were 91.01%, 93.90%, and 92.67% and that of NH3-N were 98.1%, 98.5%, and 98.9% when SRRs were 100%, 300%, and 500%, respectively. The study of the membrane fouling mechanism indicated that proteins, hydrocarbons and inorganic matter are the main elements of the cake layers.

A novel anoxic-aerobic biofilter process using new composite packing material for the treatment of rural domestic wastewater.

PubMed

Pan, L T; Han, Y

2016-01-01

A pilot scale experiment was conducted to evaluate the characteristics of contaminants removal in a continuously two-stage biological process composed of an anoxic biofilter (AF) and an biological aerated filter (BAF). This novel process was developed by introducing new composite packing material (MZF) into bioreactors to treat rural domestic wastewater. A comparative study conducted by the same process with ceramsite as packing material under the same conditions showed that a MZF system with a Fe proportion in the packing material performed better in chemical oxygen demand (COD) removal (average 91.5%), ammonia (NH4(+)-N) removal (average 98.3%), total nitrogen (TN) removal (average 64.8%) and total phosphorus (TP) removal (average 90%). After treatment of the MZF system, the concentrations of COD, NH4(+)-N, TN and TP in effluent were 20.3 mg/L, 0.5 mg/L, 11.5 mg/L and 0.3 mg/L, respectively. The simultaneously high efficiencies of nitrification, denitrification and phosphorus removal were achieved by the coupling effects of biological and chemical processes in the MZF system. The results of this study showed that the application of MZF might be a favorable choice as packing material in biofilters for treatment of rural domestic wastewater.

Cosmetic wastewater treatment by coagulation and advanced oxidation processes.

PubMed

Naumczyk, Jeremi; Bogacki, Jan; Marcinowski, Piotr; Kowalik, Paweł

2014-01-01

In this study, the treatment process of three cosmetic wastewater types has been investigated. Coagulation allowed to achieve chemical oxygen demand (COD) removal of 74.6%, 37.7% and 74.0% for samples A (Al2(SO4)3), B (Brentafloc F3) and C (PAX 16), respectively. The Fenton process proved to be effective as well - COD removal was equal to 75.1%, 44.7% and 68.1%, respectively. Coagulation with FeCl3 and the subsequent photo-Fenton process resulted in the best values of final COD removal equal to 92.4%, 62.8% and 90.2%. In case of the Fenton process, after coagulation these values were equal to 74.9%, 50.1% and 84.8%, while in case of the H2O2/UV process, the obtained COD removal was 83.8%, 36.2% and 80.9%. High value of COD removal in the Fenton process carried out for A and C wastewater samples was caused by a significant contribution of the final neutralization/coagulation. Very small effect of the oxidation reaction in the Fenton process in case of sample A resulting from the presence of antioxidants, 'OH radical scavengers' in the wastewater.

Enhancing nitrogen removal from low carbon to nitrogen ratio wastewater by using a novel sequencing batch biofilm reactor.

PubMed

Zou, Jinte; Li, Jun; Ni, Yongjiong; Wei, Su

2016-12-01

Removing nitrogen from wastewater with low chemical oxygen demand/total nitrogen (COD/TN) ratio is a difficult task due to the insufficient carbon source available for denitrification. Therefore, in the present work, a novel sequencing batch biofilm reactor (NSBBR) was developed to enhance the nitrogen removal from wastewater with low COD/TN ratio. The NSBBR was divided into two units separated by a vertical clapboard. Alternate feeding and aeration was performed in the two units, which created an anoxic unit with rich substrate content and an aeration unit deficient in substrate simultaneously. Therefore, the utilization of the influent carbon source for denitrification was increased, leading to higher TN removal compared to conventional SBBR (CSBBR) operation. The results show that the CSBBR removed up to 76.8%, 44.5% and 10.4% of TN, respectively, at three tested COD/TN ratios (9.0, 4.8 and 2.5). In contrast, the TN removal of the NSBBR could reach 81.9%, 60.5% and 26.6%, respectively, at the corresponding COD/TN ratios. Therefore, better TN removal performance could be achieved in the NSBBR, especially at low COD/TN ratios (4.8 and 2.5). Furthermore, it is easy to upgrade a CSBBR into an NSBBR in practice. Copyright © 2016. Published by Elsevier B.V.

MBR/RO/ozone processes for TFT-LCD industrial wastewater treatment and recycling.

PubMed

Chen, T K; Ni, C H; Chan, Y C; Lu, M C

2005-01-01

This research is mainly to explore the treatment capacity for TFT-LCD industrial wastewater recycling by the processes combined with membrane bioreactor (MBR), reverse osmosis (RO) and ozone(O3). The organic wastewater from the TFT-LCD industry was selected as the target. MBR, RO and ozone plants were established for evaluation. An MBR plant consisted of a 2-stage anoxic/aerobic bioreactor and an immersed UF membrane unit was employed. The effluent of MBR was conducted into the RO system then into the ozone system. The RO system consisted of a spiral membrane in the vessel. One bubble column, 75 cm high and diameter 5 cm, were used as the ozonation reactor. On the bottom of ozonation reactor is a porous diffuser for releasing gas, with an aperture of 100 microm (0.1 cm). Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 98.5%. For the TOC item, the average removal efficiency was 97.4%. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of an immersed UF membrane device incorporated with the biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After the treatment of RO, excellent water quality was found. The water quality of permeate was under 5 mg/I, 2 mg/l and 50 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled and reused for the cooling tower make-up water or other purposes. After the treatment of ozone, the treated water quality was under 5 mg/l and 0.852 mg/l for COD and TOC respectively. The test results of MBR, MBR/RO and MBR/RO/ozone processes were compared as possible appropriate treatment technologies applied in TFT-LCD industrial wastewater reuse and recycling.

Integrated aerobic biological-chemical treatment of winery wastewater diluted with urban wastewater. LED-based photocatalysis in the presence of monoperoxysulfate.

PubMed

Solís, Rafael R; Rivas, Francisco Javier; Ferreira, Leonor C; Pirra, Antonio; Peres, José A

2018-01-28

The oxidation of Winery Wastewater (WW) by conventional aerobic biological treatment usually leads to inefficient results due to the presence of organic substances, which are recalcitrant or toxic in conventional procedures. This study explores the combination of biological and chemical processes in order to complete the oxidation of biodegradable and non-biodegradable compounds in two sequential steps. Thus, a biological oxidation of a diluted WW is carried out by using the activated sludge process. Activated sludge was gradually acclimated to the Diluted Winery Wastewater (DWW). Some aspects concerning the biological process were evaluated (kinetics of the oxidation and sedimentation of the sludge produced). The biological treatment of the DWW led to a 40-50% of Chemical Oxygen Demand (COD) removal in 8 h, being necessary the application of an additional process. Different chemical processes combining UVA-LEDs radiation, monoperoxysulfate (MPS) and photocatalysts were applied in order to complete the COD depletion and efficient removal of polyphenols content, poorly oxidized in the previous biological step. From the options tested, the combination of UVA, MPS and a novel LaCoO 3 -TiO 2 composite, with double route of MPS decomposition through heterogeneous catalysis and photocatalysis, led to the best results (95% of polyphenol degradation, and additional 60% of COD removal). Initial MPS concentration and pH effect in this process were assessed.

Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration

PubMed Central

Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

2015-01-01

Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively. PMID:26729180

Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration.

PubMed

Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

2015-12-31

Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively.

Bioaugmentation for treatment of full-scale diethylene glycol monobutyl ether (DGBE) wastewater by Serratia sp. BDG-2.

PubMed

Chen, Maoxia; Fan, Rong; Zou, Wenhui; Zhou, Houzhen; Tan, Zhouliang; Li, Xudong

2016-05-15

A novel bacterial strain BDG-2 was isolated and used to augment the treatment of silicon plate manufacturing wastewater that primarily contains diethylene glycol monobutyl ether (DGBE). BDG-2 was identified as a Serratia sp. Under the optimal conditions of 30 °C, pH 9 and DGBE concentration of 2000 mg L(-1), the bioaugmented system achieved 96.92% COD removal after 39.9h. Laboratory-scale technological matching results indicated that, in a biofilm process with the addition of 100 mg L(-1) ammonia and 5 mg L(-1) total phosphorus (TP), 70.61% COD removal efficiency could be obtained in 46 h. Addition of polyaluminium chloride (PAC) to the reactors during the suspension process enhanced the settleability of the BDG-2 culture. Subsequently, successful start-up and stable operation of a full-scale bioaugmented treatment facilities were accomplished, and the volumetric organic load in the plug-flow aeration tank was 2.17 ± 0.81 kg m(-3) d(-1). The effluent COD of the facilities was stable and always below 100 mg L(-1). Copyright © 2016 Elsevier B.V. All rights reserved.

Pilot-Scale Hydrolysis-Aerobic Treatment for Actual Municipal Wastewater: Performance and Microbial Community Analysis

PubMed Central

Bian, Xiao; Wang, Kaijun

2018-01-01

Low-energy cost wastewater treatment is required to change its current energy-intensive status. Although promising, the direct anaerobic digestion of municipal wastewater treatment faces challenges such as low organic content and low temperature, which require further development. The hydrolysis-aerobic system investigated in this study utilized the two well-proven processes of hydrolysis and aerobic oxidation. These have the advantages of efficient COD removal and biodegradability improvement with limited energy cost due to their avoidance of aeration. A pilot-scale hydrolysis-aerobic system was built for performance evaluation with actual municipal wastewater as feed. Results indicated that as high as 39–47% COD removal was achieved with a maximum COD load of 1.10 kg/m3·d. The dominant bacteria phyla included Proteobacteria (36.0%), Planctomycetes (15.4%), Chloroflexi (9.7%), Bacteroidetes (7.7%), Firmicutes (4.4%), Acidobacteria (2.5%), Actinobacteria (1.8%) and Synergistetes (1.3%), while the dominant genera included Thauera (3.42%) and Dechloromonas (3.04%). The absence of methanogens indicates that the microbial community was perfectly retained in the hydrolysis stage instead of in the methane-producing stage. PMID:29522450

Bio-energy generation in an affordable, single-chamber microbial fuel cell integrated with adsorption hybrid system: effects of temperature and comparison study.

PubMed

Tee, Pei-Fang; Abdullah, Mohammad Omar; Tan, Ivy A W; Amin, Mohamed A M; Nolasco-Hipolito, Cirilo; Bujang, Kopli

2018-04-01

A microbial fuel cell (MFC) integrated with adsorption system (MFC-AHS) is tested under various operating temperatures with palm oil mill effluent as the substrate. The optimum operating temperature for such system is found to be at ∼35°C with current, power density, internal resistance (R in ), Coulombic efficiency (CE) and maximum chemical oxygen demand (COD) removal of 2.51 ± 0.2 mA, 74 ± 6 mW m -3 , 25.4 Ω, 10.65 ± 0.5% and 93.57 ± 1.2%, respectively. Maximum current density increases linearly with temperature at a rate of 0.1772 mA m -2  °C -1 , whereas maximum power density was in a polynomial function. The temperature coefficient (Q 10 ) is found to be 1.20 between 15°C and 35°C. Present studies have demonstrated better CE performance when compared to other MFC-AHSs. Generally, MFC-AHS has demonstrated higher COD removals when compared to standalone MFC regardless of operating temperatures. ACFF: activated carbon fiber felt; APHA: American Public Health Association; CE: Coulombic efficiency; COD: chemical oxygen demand; ECG: electrocardiogram; GAC: granular activated carbon; GFB: graphite fiber brush; MFC: microbial fuel cell; MFC-AHS: microbial fuel cell integrated with adsorption hybrid system; MFC-GG: microbial fuel cell integrated with graphite granules; POME: palm oil mill effluent; PTFE: polytetrafluoroethylene; SEM: scanning electron microscope.

Treatment of reverse-osmosis concentrate of printing and dyeing wastewater by electro-oxidation process with controlled oxidation-reduction potential (ORP).

PubMed

Wang, Jiade; Zhang, Tian; Mei, Yu; Pan, Bingjun

2018-06-01

Reverse osmosis concentrate (ROC) of printing and dyeing wastewater remains as a daunting environmental issue, which is characterized by high salinity, chemical oxygen demand (COD), chroma and low biodegradability. In this study electro-oxidation process (PbO 2 /Ti electrode) coupled with oxidation-reduction potential (ORP) online monitor was applied to treat such a ROC effluent. The results show that with the increase of specific electrical charge (Q sp ), the removal efficiencies of COD, TN and chroma increased significantly at the incipience and then reached a gentle stage; the optimal total current efficiency (12.04 kWh m -3 ) was obtained with the current density of 10 mA cm -2 (Q sp , 3.0 Ah L -1 ). Meanwhile, some inorganic ions can be simultaneously removed to varying degrees. FTIR analyses indicated that the macromolecular organics were decomposed into smaller molecules. A multi-parameter linear relationship between ORP and Q sp , COD and Cl - concentration was established, which can quantitatively reflect the effect of current density, chloride ion concentration, pollutants and reaction time on the performance of the electro-oxidation system. As compared to a traditional constant-current system, the constant-ORP system developed in this study (through the back-propagation neural network [BPN] model with ORP monitoring) approximately reduced the energy cost by 24-29%. The present work is expected to provide a potential alternative in optimizing the electro-oxidation process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Treatment of oilfield produced water by anaerobic process coupled with micro-electrolysis.

PubMed

Li, Gang; Guo, Shuhai; Li, Fengmei

2010-01-01

Treatment of oilfield produced water was investigated using an anaerobic process coupled with micro-electrolysis (ME), focusing on changes in chemical oxygen demand (COD) and biodegradability. Results showed that COD exhibited an abnormal change in the single anaerobic system in which it increased within the first 168 hr, but then decreased to 222 mg/L after 360 hr. The biological oxygen demand (five-day) (BODs)/COD ratio of the water increased from 0.05 to 0.15. Hydrocarbons in the wastewater, such as pectin, degraded to small molecules during the hydrolytic acidification process. Comparatively, the effect of ME was also investigated. The COD underwent a slight decrease and the BOD5/COD ratio of the water improved from 0.05 to 0.17 after ME. Removal of COD was 38.3% under the idealized ME conditions (pH 6.0), using iron and active carbon (80 and 40 g/L, respectively). Coupling the anaerobic process with ME accelerated the COD removal ratio (average removal was 53.3%). Gas chromatography/mass spectrometry was used to analyze organic species conversion. This integrated system appeared to be a useful option for the treatment of water produced in oilfields.

The Effectiveness of Organic Pollutants Removal in Constructed Wetland with Horizontal Sub-Surface Flow / Efektywność Usuwania Zanieczyszczeń Organicznych W Oczyszczalni Hydrofitowej

NASA Astrophysics Data System (ADS)

Jakubaszek, Anita; Sadecka, Zofia

2015-03-01

This paper presents the results of the research work related to the removal efficiency from wastewater organic pollutants and suspended solids at HSSF (horizontal subsurface flow) constructed wetland. The average effectiveness defined as loss of value COD in wastewater has reached 77%, for BOD5 - 80% and TOC - 82%. The effect of seasonal temperature changes and the period of plant vegetation and rest on the effectiveness of wastewater treatment were also analyzed. The results of the presented research showed a decrease in the efficiency of removing organic pollutants from wastewater and suspended solids in the autumn and winter. During the vegetation the object in Małyszyn has been characterized by the effectiveness of wastewater treatment at the level of 78% for COD, 82% for BOD5, and in the non-vegetation period the effectiveness has decreased up to 75% for COD and 74% for BOD5. During the plants growth the total suspension was removed in 88%, whereas during the plants rest efficiency of removing lowered to 69%. W pracy przedstawiono wyniki badań dotyczące efektywności usuwania ze ścieków zanieczyszczeń organicznych w oczyszczalni hydrofitowej. Średnia skuteczność oczyszczania wyrażona jako obniżenie wartości ChZT w ściekach była na poziomie 77%, dla BZT5 80%, a dla OWO 82%. Analizowano również wpływ sezonowych zmian temperatury oraz okresu wegetacji i spoczynku roślin na skuteczność oczyszczania ścieków. Wyniki badań wykazały obniżenie efektywności usuwania zanieczyszczeń organicznych ze ścieków wyrażonych przez ChZT i BZT5 oraz zawiesiny ogólnej w okresie jesienno-zimowym. W okresie wegetacyjnym obiekt w Małyszynie charakteryzował się efektywnością oczyszczania ścieków na poziomie: 78% dla ChZT, 82% dla BZT5, a w sezonie pozawegetacyjnym skuteczność uległa obniżeniu do 75% w przypadku ChZT oraz 74% dla BZT5. Zawiesina ogólna w okresie wegetacji trzciny usuwana była w 88%, a w okresie powegetacyjnym w 69%.

Using one filter stage of unsaturated/saturated vertical flow filters for nitrogen removal and footprint reduction of constructed wetlands.

PubMed

Morvannou, Ania; Troesch, Stéphane; Esser, Dirk; Forquet, Nicolas; Petitjean, Alain; Molle, Pascal

2017-07-01

French vertical flow constructed wetlands (VFCW) treating raw wastewater have been developed successfully over the last 30 years. Nevertheless, the two-stage VFCWs require a total filtration area of 2-2.5 m 2 /P.E. Therefore, implementing a one-stage system in which treatment performances reach standard requirements is of interest. Biho-Filter ® is one of the solutions developed in France by Epur Nature. Biho-Filter ® is a vertical flow system with an unsaturated layer at the top and a saturated layer at the bottom. The aim of this study was to assess this new configuration and to optimize its design and operating conditions. The hydraulic functioning and pollutant removal efficiency of three different Biho-Filter ® plants commissioned between 2011 and 2012 were studied. Outlet concentrations of the most efficient Biho-Filter ® configuration are 70 mg/L, 15 mg/L, 15 mg/L and 25 mg/L for chemical oxygen demand (COD), 5-day biological oxygen demand (BOD 5 ), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN), respectively. Up to 60% of total nitrogen is removed. Nitrification efficiency is mainly influenced by the height of the unsaturated zone and the recirculation rate. The optimum recirculation rate was found to be 100%. Denitrification in the saturated zone works at best with an influent COD/NO 3 -N ratio at the inflet of this zone larger than 2 and a hydraulic retention time longer than 0.75 days.

Improvement of the degradation of sulfate rich wastewater using sweetmeat waste (SMW) as nutrient supplement.

PubMed

Das, Bidus Kanti; Roy, Shantonu; Dev, Subhabrata; Das, Debabrata; Bhattacharya, Jayanta

2015-12-30

External dosing of sweetmeat waste (SMW) dosing into exhausted upflow packed bed bioreactor (PBR) resulted in prompt reactivation of SO4(2-) removal. Different SMW concentrations in terms of chemical oxygen demand (COD)/SO4(2-) ratios (1, 2, 4 and 8) were introduced into four identical PBR where process stability was found within 3 weeks of operation. SO4(2-) removal was proportional to COD/SO4(2-) ratios up to 4 at which maximum sulfate removal (99%) was achieved at a rate of 607 mg/d. The value of COD consumption:SO4(2-)removal was much higher at ratio 4 than 8 whereas, ratio 2 was preferred over all. Net effluent acetate concentration profile and total microbial population attached to the reactor matrices were corresponding to COD/SO4(2-) ratio as 4>8>2>1. Sulfate reducing bacteria (SRB) population was found to be inversely proportional to COD/SO4(2-) ratio in which acetate oxidizing SRB and fermentative bacteria were the dominant. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous removal of AOX and COD from real recycled paper wastewater using GAC-SBBR.

PubMed

Osman, Wan Hasnidah Wan; Abdullah, Siti Rozaimah Sheikh; Mohamad, Abu Bakar; Kadhum, Abdul Amir H; Rahman, Rakmi Abd

2013-05-30

A lab-scale granular activated carbon sequencing batch biofilm reactor (GAC-SBBR), a combined adsorption and biological process, was developed to treat real wastewater from a recycled paper mill. In this study, one-consortia of mixed culture (4000-5000 mg/L) originating from recycled paper mill activated sludge from Kajang, Malaysia was acclimatized. The GAC-SBBR was fed with real wastewater taken from the same recycled paper mill, which had a high concentration of chemical oxygen demand (COD) and adsorbable organic halides (AOX). The operational duration of the GAC-SBBR was adjusted from 48 h to 24, 12 and finally 8 h to evaluate the effect of the hydraulic retention time (HRT) on the simultaneous removal of COD and AOX. The COD and AOX removals were in the range of 53-92% and 26-99%, respectively. From this study, it was observed that the longest HRT (48 h) yielded a high removal of COD and AOX, at 92% and 99%, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Overall effect of carbon production and nutrient release in sludge holding tank on mainstream biological nutrient removal efficiency.

PubMed

Jabari, Pouria; Yuan, Qiuyan; Oleszkiewicz, Jan A

2017-09-11

The potential of hydrolysis/fermentation of activated sludge in sludge holding tank (SHT) to produce additional carbon for the biological nutrient removal (BNR) process was investigated. The study was conducted in anaerobic batch tests using the BNR sludge (from a full-scale Westside process) and the mixture of BNR sludge with conventional non-BNR activated sludge (to have higher biodegradable particulate chemical oxygen demand (bpCOD) in sludge). The BioWin 4.1 was used to simulate the anaerobic batch test of the BNR sludge. Also, the overall effect of FCOD production and nutrient release on BNR efficiency of the Westside process was estimated. The experimental results showed that the phosphorous uptake of sludge increased during hydrolysis/ fermentation condition up to the point when poly-P was completely utilized; afterwards, it decreased significantly. The BioWin simulation could not predict the loss of aerobic phosphorous uptake after poly-P was depleted. The results showed that in the case of activated sludge with relatively higher bpCOD (originating from plants with short sludge retention time or without primary sedimentation), beneficial effect of SHT on BNR performance is feasible. In order to increase the potential of SHT to enhance BNR efficiency, a relatively low retention time and high sludge load is recommended.

Treatment of real coal gasification wastewater using a novel integrated system of anoxic hybrid two stage aerobic processes: performance and the role of pure oxygen microbubble.

PubMed

Zhuang, Haifeng; Han, Hongjun; Shan, Shengdao

2016-06-01

A novel integrated system of anoxic-pure oxygen microbubble-activated sludge reactor-moving bed biofilm reactor was employed in treatment of real coal gasification wastewater. The results showed the integrated system had efficient performance of pollutants removal in short hydraulic retention time. While pure oxygen microbubble with the flow rate of 1.5 L/h and NaHCO3 dosage ratio of 2:1 (amount NaHCO3 to NH4 (+)-N ratio, mol: mol) were used, the removal efficiencies of COD, total phenols (TPh) and NH4 (+)-N reached 90, 95, and 95 %, respectively, with the influent loading rates of 3.4 kg COD/(m(3) d), 0.81 kg TPh/(m(3) d), and 0.28 kg NH4 (+)-N/(m(3) d). With the recycle ratio of 300 %, the concentrations of NO2 (-)-N and NO3 (-)-N in effluent decreased to 12 and 59 mg/L, respectively. Meanwhile, pure oxygen microbubble significantly improved the enzymatic activities and affected the effluent organic compositions and reduced the foam expansion. Thus, the novel integrated system with efficient, stable, and economical advantages was suitable for engineering application.

Treatment of azo dye Acid Orange 52 using ozonation and completed-mixed activated sludge process

NASA Astrophysics Data System (ADS)

Abidin, C. Z. A.; Fahmi; Ong, S. A.; Ahmad, R.; Sabri, S. N.

2017-06-01

In this study, the characteristic of colour and COD removal of azo dye Acid Orange 52 (AO52) by ozonation, in combination with complete-mixed activated sludge process (CMAS) was evaluated. The experimentation was arranged in two phases: during the first one, only ozonation was performed, while, during the second phase, it was integrated with CMAS. The performance of colour and COD concentration of AO52 with and without CMAS treatment, is compared and evaluated. From the results, it is obvious that high decolourization from the start of CMAS was contributed from the pre-treatments. The colour removal was due to the fact that ozonation able to cleave the azo bonds that represent colour. Thus, CMAS without pre-treatment are unable to decolourize the dyes sufficiently. 59.6% COD was removed from the first-stage, while merely 9.8% COD fraction removed from the subsequence second-stage CMAS. It is suggested that the rapid COD removal without ozonation are due to activated sludge adsorption processes. The decreased of mixed liquor suspended solids (MLSS) affected the CMAS performances, as the biomass decreased due to lack of nutrient for activated sludge microorganisms to multiply. Results from pre-ozonation alone contributed more than 50% of total COD removal, which indicated that at higher ozone dosage, tend to mineralize azo dye. Thus, ozonation not oxidized the dye though complete mineralization that produce carbon dioxide and water. However, it is a potential process for enhancing colour removal and biodegradability of dye-containing wastewater, once the appropriate ozonation time is determined. Therefore, the role of ozonation seems to break down the dye molecules and created ozonation by-product that is easily biodegraded in the subsequent biological treatment.

High rate manure supernatant digestion.

PubMed

Bergland, Wenche Hennie; Dinamarca, Carlos; Toradzadegan, Mehrdad; Nordgård, Anna Synnøve Røstad; Bakke, Ingrid; Bakke, Rune

2015-06-01

The study shows that high rate anaerobic digestion may be an efficient way to obtain sustainable energy recovery from slurries such as pig manure. High process capacity and robustness to 5% daily load increases are observed in the 370 mL sludge bed AD reactors investigated. The supernatant from partly settled, stored pig manure was fed at rates giving hydraulic retention times, HRT, gradually decreased from 42 to 1.7 h imposing a maximum organic load of 400 g COD L(-1) reactor d(-1). The reactors reached a biogas production rate of 97 g COD L(-1) reactor d(-1) at the highest load at which process stress signs were apparent. The yield was ∼0.47 g COD methane g(-1) CODT feed at HRT above 17 h, gradually decreasing to 0.24 at the lowest HRT (0.166 NL CH4 g(-1) CODT feed decreasing to 0.086). Reactor pH was innately stable at 8.0 ± 0.1 at all HRTs with alkalinity between 9 and 11 g L(-1). The first stress symptom occurred as reduced methane yield when HRT dropped below 17 h. When HRT dropped below 4 h the propionate removal stopped. The yield from acetate removal was constant at 0.17 g COD acetate removed per g CODT substrate. This robust methanogenesis implies that pig manure supernatant, and probably other similar slurries, can be digested for methane production in compact and effective sludge bed reactors. Denaturing gradient gel electrophoresis (DGGE) analysis indicated a relatively fast adaptation of the microbial communities to manure and implies that non-adapted granular sludge can be used to start such sludge bed bioreactors. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Electrochemical oxidation of textile industry wastewater by graphite electrodes.

PubMed

Bhatnagar, Rajendra; Joshi, Himanshu; Mall, Indra D; Srivastava, Vimal C

2014-01-01

In the present article, studies have been performed on the electrochemical (EC) oxidation of actual textile industry wastewater by graphite electrodes. Multi-response optimization of four independent parameters namely initial pH (pHo): 4-10, current density (j): 27.78-138.89 A/m(2), NaCl concentration (w): 0-2 g/L and electrolysis time (t): 10-130 min have been performed using Box-Behnken (BB) experimental design. It was aimed to simultaneously maximize the chemical oxygen demand (COD) and color removal efficiencies and minimize specific energy consumption using desirability function approach. Pareto analysis of variance (ANOVA) showed a high coefficient of determination value for COD (R(2) = 0.8418), color (R(2) = 0.7010) and specific energy (R(2) = 0.9125) between the experimental values and the predicted values by a second-order regression model. Maximum COD and color removal and minimum specific energy consumed was 90.78%, 96.27% and 23.58 kWh/kg COD removed, respectively, were observed at optimum conditions. The wastewater, sludge and scum obtained after treatment at optimum condition have been characterized by various techniques. UV-visible study showed that all azo bonds of the dyes present in the wastewater were totally broken and most of the aromatic rings were mineralized during EC oxidation with graphite electrode. Carbon balance showed that out of the total carbon eroded from the graphite electrodes, 27-29.2% goes to the scum, 71.1-73.3% goes into the sludge and rest goes to the treated wastewater. Thermogravimetric analysis showed that the generated sludge and scum can be dried and used as a fuel in the boilers/incinerators.

Significance of dissolved methane in effluents of anaerobically treated low strength wastewater and potential for recovery as an energy product: A review.

PubMed

Crone, Brian C; Garland, Jay L; Sorial, George A; Vane, Leland M

2016-11-01

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10-30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11-100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Microporous membranes can recover up to 98.9% of dissolved methane in AnMBR effluents which have low COD and SS concentrations. Sequential Down-flow Hanging Sponge (DHS) reactors have been used to recover between 57 and 88% of dissolved methane from Upflow Anaerobic Sludge Blanket (UASB) reactor effluent at concentrations of greater than 30% and oxidize the rest for a 99% removal of total dissolved methane. They can also remove 90% of suspended solids and COD in UASB effluents and produce a high quality effluent. In situ degassing can increase process stability, COD removal, biomass retention, and headspace methane concentrations. A model for estimating energy consumption associated with membrane-based dissolved methane recovery predicts that recovered dissolved and headspace methane may provide all the energy required for operation of an anaerobic system treating DWW at psychrophilic temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Upgrading the hydrolytic potential of immobilized bacterial pretreatment to boost biogas production.

PubMed

Ushani, U; Kavitha, S; Johnson, M; Yeom, Ick Tae; Banu, J Rajesh

2017-01-01

In this study, surfactant dioctyl sodium sulphosuccinate (DOSS)-mediated immobilized bacterial pretreatment of waste activated sludge (WAS) was experimentally proved to be an efficient and economically feasible process for enhancing the biodegradability of WAS. The maximal floc disruption with negligible cell cleavage was achieved at surfactant dosage of 0.009 g/g SS. Results of the outcome of bacterial pretreatment of sludge biomass revealed that chemical oxygen demand (COD) solubilization for deflocculated (EPS removed-bacterially pretreated) sludge was 20 %, which was higher than that of flocculated (14 %) or control (5 %). The pretreatment was swift in deflocculated sludge with a rate constant of about 0.064 h -1 . Biochemical methane potential (BMP) assay resulted in significant methane yield at 0.24 gCOD/gCOD for deflocculated sludge. Economic assessment of the proposed method showed a net profit of about 57.39 USD/ton of sludge.

Economical and technical efficiencies evaluation of full scale piggery wastewater treatment BNR plants.

PubMed

Oa, S W; Choi, E; Kim, S W; Kwon, K H; Min, K S

2009-01-01

A method evaluating the economic efficiency of piggery waste treatment plant based on kinetics for nitrogen removal performances is executed in this study and five full scale plants were evaluated, monitored intensively during one year under steady-state conditions. The performance data from those surveyed plants were recalculated by first-order kinetic equation instead of the Monod's equation, and the nitrogen removal kinetics related with COD/TKN ratios. Two plants adapting two extreme strategies for pre treatment, 'excess phase separation', and 'minimum phase separation', were evaluated by the assessment of life cycle cost (LCC). Although the compared two plants use an opposite strategy to each other, similar evaluation results are deduced by nitrogen removal efficiencies and operational and construction costs. But the proportions of constituent elements are as different as two opposite strategies, so electrical and construction costs are inversely proportional to chemical costs and operational costs respectively.

Effect of temperature downshifts on a bench-scale hybrid A/O system: Process performance and microbial community dynamics.

PubMed

Zhou, Hexi; Li, Xiangkun; Chu, Zhaorui; Zhang, Jie

2016-06-01

Effect of temperature downshifts on process performance and bacterial community dynamics was investigated in a bench-scale hybrid A/O system treating real domestic wastewater. Results showed that the average COD removal in this system reached 90.5%, 89.1% and 90.3% for Run 1 (25 °C), Run 2 (15 °C) and Run 3 (10 °C), respectively, and variations in temperature barely affected the effluent COD concentration. The average removal efficiencies of NH4(+)-N were 98.4%, 97.8%, 95.7%, and that of TN were 77.1%, 61.8%, 72% at 25 °C, 15 °C and 10 °C, respectively. Although the hybrid system was subjected to low temperature, this process effectively removed NH4(+)-N and TN even at 10 °C with the average effluent concentrations of 2.4 mg/L and 14.3 mg/L, respectively. Results from high-throughput sequencing analysis revealed that when the operation temperature decreased from 25 °C to 10 °C, the richness and diversity indexes of the system decreased in the sludge samples, while underwent an increase in the biofilm samples. Furthermore, the major heterotrophic bacteria consisted of Lewinella, Lutimonas, Chitinophaga and Fluviicola at 10 °C, which could be central to effective COD removal at low temperature. Additionally, Azospira, one denitrifying-related genus increased from 0.4% to 4.45% in the biofilm samples, with a stable TN removal in response to temperature downshifts. Nitrosomonas and Nitrospira increased significantly in the biofilm samples, implying that the attached biofilm contributed to more nitrification at low temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fenton treatment of bio-treated fermentation-based pharmaceutical wastewater: removal and conversion of organic pollutants as well as estimation of operational costs.

PubMed

Cheng, Yunqin; Chen, Yunlu; Lu, Juncheng; Nie, Jianxin; Liu, Yan

2018-04-01

The Fenton process is used as a tertiary treatment to remove organic pollutants from the effluent of bio-treated pharmaceutical wastewater (EBPW). The optimal and most appropriate Fenton conditions were determined by an orthogonal array test and single-factor experiments. The removal of chemical oxygen demand (COD) was influenced by the following factors in a descending order: H 2 O 2 /Fe(II) molar ratio > H 2 O 2 dosage > reaction time. Under the most appropriate Fenton conditions (H 2 O 2 /Fe(II) molar ratio of 1:1, H 2 O 2 dosage of 120 mg L -1 and reaction time of 10 min), the COD and dissolved organic carbon (DOC) were removed with efficiencies of 62 and 53%, respectively, which met the national discharge standard (GB 21903-2008) for the Lake Tai Basin, China. However, the Fenton treatment was inadequate for removal of N compounds, and the removal of organic nitrogen led to an increment in N-NH 3 from 3.28 to 19.71 mg L -1 . Proteins and polysaccharides were completely removed, and humic acids (HAs) were partly removed with an efficiency of 55%. Three-dimensional excitation/emission matrix spectra (3DEEMs) indicated complete removal of fulvic acid-like substances and 90% reduction in the florescence intensity of humic acid-like substances. Organic pollutants with molecular weights (MW) > 10 kDa were completely removed, MW 5-10 kDa were degraded into smaller MW ones, and some low molecular weight acids (MW 0.1-1 kDa) were mineralized during the Fenton process. Some species, including pharmaceutical intermediates and solvents were detected by gas chromatography-mass spectrometry (GC-MS). The operational costs of the Fenton's treatment were estimated to be 0.58 yuan RMB/m 3 EBPW based on reagent usage and iron sludge treatment and disposal.

Comparison of coagulation pretreatment of produced water from natural gas well by polyaluminium chloride and polyferric sulphate coagulants.

PubMed

Zhai, Jun; Huang, Zejin; Rahaman, Md Hasibur; Li, Yue; Mei, Longyue; Ma, Hongpu; Hu, Xuebin; Xiao, Haiwen; Luo, Zhiyong; Wang, Kunping

2017-05-01

This study aimed to optimise coagulation pretreatment of the produced water (PW) collected from a natural gas field. Two coagulants, polyferric sulphate (PFS) and polyaluminium chloride (PACl), were applied separately for the organics, suspended solids (SS), and colour removal. Treatment performance at different coagulant dosages, initial pH values, stirring patterns, and the addition of cationic polyacrylamide (PAM) was investigated in jar tests. The optimal coagulation conditions were dosage of PACl 25 g/L or PFS 20 g/L with that of PAM 30 mg/L, initial pH of 11, and fast mixing of 1.5 min (for PACl) or 2 min (for PFS) at 250 rpm followed by slow mixing of 15 min at 50 rpm for both coagulants. PACl performed better than PFS to remove chemical oxygen demand (COD), total organic carbon (TOC), SS, and colour, and achieved a removal efficiency of 90.1%, 89.4%, 99.0%, and 99.9%, respectively, under the optimal condition; while PFS efficiency was 86.1%, 86.1%, 99.0%, and 98.2%, respectively. However, oil removal was higher in PFS coagulation compared to PACl and showed 98.9% and 95.3%, respectively. Biodegradability, ratio of the biological oxygen demand (five-day) (BOD 5 )/COD, of the PW after pretreatment increased from 0.08 to 0.32 for PFS and 0.43 for PACl. Zeta potential (Z-potential) analysis at the optimum coagulant dosage of PACl and PFS suggests that charge neutralisation was the predominant mechanism during coagulation. Better efficiency was observed at higher pH. The addition of PAM and starring pattern had a minor influence on the removal performance of both coagulants. The results suggest that PACl or PFS can be applied for the pretreatment of PW, which can provide substantial removal of carbon, oil, and colour, a necessary first step for subsequent main treatment units such as chemical oxidation or biological treatment.

Comparison of the efficiencies of attached- versus suspended-growth SBR systems in the treatment of recycled paper mill wastewater.

PubMed

Muhamad, Mohd Hafizuddin; Sheikh Abdullah, Siti Rozaimah; Abu Hasan, Hassimi; Abd Rahim, Reehan Adnee

2015-11-01

The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of soluble and particulate substrate on the carbon and energy footprint of wastewater treatment processes.

PubMed

Gori, Riccardo; Jiang, Lu-Man; Sobhani, Reza; Rosso, Diego

2011-11-15

Most wastewater treatment plants monitor routinely carbonaceous and nitrogenous load parameters in influent and effluent streams, and often in the intermediate steps. COD fractionation discriminates the selective removal of VSS components in different operations, allowing accurate quantification of the energy requirements and mass flows for secondary treatment, sludge digestion, and sedimentation. We analysed the different effects of COD fractions on carbon and energy footprint in a wastewater treatment plant with activated sludge in nutrient removal mode and anaerobic digestion of the sludge with biogas energy recovery. After presenting a simple rational procedure for COD and solids fractions quantification, we use our carbon and energy footprint models to quantify the effects of varying fractions on carbon equivalent flows, process energy demand and recovery. A full-scale real process was modelled with this procedure and the results are reported in terms of energy and carbon footprint. For a given process, the increase of the ratio sCOD/COD increases the energy demand on the aeration reactors, the associated CO(2) direct emission from respiration, and the indirect emission for power generation. Even though it appears as if enhanced primary sedimentation is a carbon and energy footprint mitigation practice, care must be used since the nutrient removal process downstream may suffer from an excessive bCOD removal and an increased mean cell retention time for nutrient removal may be required. Copyright © 2011 Elsevier Ltd. All rights reserved.

Highway-runoff quality, and treatment efficiencies of a hydrodynamic-settling device and a stormwater-filtration device in Milwaukee, Wisconsin

USGS Publications Warehouse

Horwatich, Judy A.; Bannerman, Roger T.; Pearson, Robert

2011-01-01

The treatment efficiencies of two prefabricated stormwater-treatment devices were tested at a freeway site in a high-density urban part of Milwaukee, Wisconsin. One treatment device is categorized as a hydrodynamic-settling device (HSD), which removes pollutants by sedimentation and flotation. The other treatment device is categorized as a stormwater-filtration device (SFD), which removes pollutants by filtration and sedimentation. During runoff events, flow measurements were recorded and water-quality samples were collected at the inlet and outlet of each device. Efficiency-ratio and summation-of-load (SOL) calculations were used to estimate the treatment efficiency of each device. Event-mean concentrations and loads that were decreased by passing through the HSD include total suspended solids (TSS), suspended sediment (SS), total phosphorus (TP), total copper (TCu), and total zinc (TZn). The efficiency ratios for these constituents were 42, 57, 17, 33, and 23 percent, respectively. The SOL removal rates for these constituents were 25, 49, 10, 27, and 16 percent, respectively. Event-mean concentrations and loads that increased by passing through the HSD include chloride (Cl), total dissolved solids (TDS), and dissolved zinc (DZn). The efficiency ratios for these constituents were -347, -177, and 20 percent, respectively. Four constituents—dissolved phosphorus (DP), chemical oxygen demand (COD), total polycyclic aromatic hydrocarbon (PAH), and dissolved copper (DCu)—are not included in the list of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Event-mean concentrations and loads that decreased by passing through the SFD include TSS, SS, TP, DCu, TCu, DZn, TZn, and COD. The efficiency ratios for these constituents were 59, 90, 40, 21, 66, 23, 66, and 18, respectively. The SOLs for these constituents were 50, 89, 37, 19, 60, 20, 65, and 21, respectively. Two constituents—DP and PAH—are not included in the lists of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Similar to the HSD, the average efficiency ratios and SOLs for TDS and Cl were negative. Flow rates, high concentrations of SS, and particle-size distributions (PSD) can affect the treatment efficacies of the two devices. Flow rates equal to or greater than the design flow rate of the HSD had minimal or negative removal efficiencies for TSS and SS loads. Similar TSS removal efficiencies were observed at the SFD, but SS was consistently removed throughout the flow regime. Removal efficiencies were high for both devices when concentrations of SS and TSS approached 200 mg/L. A small number of runoff events were analyzed for PSD; the average sand content at the HSD was 33 percent and at the SFD was 71 percent. The 71-percent sand content may reflect the 90-percent removal efficiency of SS at the SFD. Particles retained at the bottom of both devices were largely sand-size or greater.

Effect of adding low-concentration of rhamnolipid on reactor performances and microbial community evolution in MBBRs for low C/N ratio and antibiotic wastewater treatment.

PubMed

Peng, Pengcheng; Huang, Hui; Ren, Hongqiang

2018-05-01

This study aims to explore the potential of low-concentration of rhamnolipid in efficient treatment of wastewater with poor biodegradability. Six lab-scale moving bed biofilm reactors (MBBRs) were applied to investigate the effect of rhamnolipid concentration (0, 20, 50 mg/L) on pollutants removal, biomass accumulation, microbial morphology and community evolution in synthetic low C/N ratio (3:1) and antibiotic (50 μg/L tetracycline) wastewater. 20 mg/L rhamnolipid treated groups exhibited significant increase (p < 0.05) of chemical oxygen demand (COD) removal and volatile solid (VS) content in both synthetic wastewater. Hydrogenophaga and Aeromonas were dominant in all reactors in which Aeromonas was positively correlated with the removal of COD and ammonia nitrogen (NH 4 + -N). Besides, Methyloversatilis became dominant only in 20 mg/L rhamnolipid treated groups and was positively correlated with VS. This study provides a novel and feasible strategy for treating poorly biodegradable wastewater by biofilm process with moderate amount of rhamnolipid. Copyright © 2018 Elsevier Ltd. All rights reserved.

Recirculation or artificial aeration in vertical flow constructed wetlands: a comparative study for treating high load wastewater.

PubMed

Foladori, Paola; Ruaben, Jenny; Ortigara, Angela R C

2013-12-01

Vertical subsurface-flow constructed wetlands at pilot-scale have been applied to treat high hydraulic and organic loads by implementing the following configurations: (1) intermittent recirculation of the treated wastewater from the bottom to the top of the bed, (2) intermittent artificial aeration supplied at the bottom of the bed and (3) the combination of both. These configurations were operated with a saturated bottom layer for a 6h-treatment phase, followed by a free drainage phase prior to a new feeding. COD removal efficiency was 85-90% in all the configurations and removed loads were 54-70 gCOD m(-2)d(-1). The aerated and recirculated wetland resulted in a higher total nitrogen removal (8.6 gN m(-2)d(-1)) due to simultaneous nitrification/denitrification, even in the presence of intermittent aeration (6.8 Nm(3)m(-2)d(-1)). The extra investment needed for implementing aeration/recirculation would be compensated for by a reduction of the surface area per population equivalent, which decreased to 1.5m(2)/PE. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ozone disintegration of excess biomass and application to nitrogen removal.

PubMed

Park, Ki Young; Lee, Jae Woo; Ahn, Kyu-Hong; Maeng, Sung Kyu; Hwang, Jong Hyuk; Song, Kyung-Guen

2004-01-01

A pilot-scale facility integrated with an ozonation unit was built to investigate the feasibility of using ozone-disintegration byproducts of wasted biomass as a carbon source for denitrification. Ozonation of biomass resulted in mass reduction by mineralization as well as by ozone-disintegrated biosolids recycling. Approximately 50% of wasted solids were recovered as available organic matter (ozonolysate), which included nonsettleable microparticles and soluble fractions. Microparticles were observed in abundance at relatively low levels of ozone doses, while soluble fractions became dominant at higher levels of ozone doses in ozone-disintegrated organics. Batch denitrification experiments showed that the ozonolysate could be used as a carbon source with a maximum denitrification rate of 3.66 mg nitrogen (N)/g volatile suspended solids (VSS) x h. Ozonolysate was also proven to enhance total nitrogen removal efficiency in the pilot-scale treatment facility. An optimal chemical oxygen demand (COD)-to-nitrogen ratio for complete denitrification was estimated as 5.13 g COD/g N. The nitrogen-removal performance of the modified intermittently decanted extended aeration process dependent on an external carbon supply could be described as a function of solids retention time.

Evaluation of the treatment performance and microbial communities of a combined constructed wetland used to treat industrial park wastewater.

PubMed

Xu, Ming; Liu, Weijing; Li, Chao; Xiao, Chun; Ding, Lili; Xu, Ke; Geng, Jinju; Ren, Hongqiang

2016-06-01

Constructed wetlands are ecosystems that use plants and microorganisms to remediate pollution in soil and water. In this study, two parallel pilot-scale vertical flow wetland and horizontal flow wetland (VF-HF) systems were implemented to investigate the treatment performance and microorganism community structure in the secondary effluent of an industrial park wastewater treatment plant (WWTP) with a loading rate of 100 mm/day near the Yangtze River in Suzhou City, East China. Removal efficiencies of 82.3, 69.8, 77.8, and 32.3 were achieved by the VF-HF systems for ammonium nitrogen (NH4 (+)-N), total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD), respectively. The VF system specialized in COD and NH4 (+)-N removal (73.6 and 79.2 %), whereas the HF system mainly contributed to TN removal (63.5 %). The effluents in all seasons are capable of achieving the "surface water environmental quality standard" (GB3838-2002) grade IV. In the VF system, the 16S gene and nirK gene were significantly correlated with depth, with the 16S gene showing significant correlations with the dissolved oxygen (DO) level (r = 0.954, p < 0.05), which was determined by real-time PCR and high-throughput sequencing. Many types of bacteria capable of biodegradation, including nitrifiers, denitrifiers, and polyaromatic hydrocarbon (PAH) degraders (improvement of the BOD5/COD ratio), were observed, and they contributed to approximately 90 % of the nitrogen removal in the VF-HF system.

High-efficiency treatment of PTA wastewater using a biogas jet assisted anaerobic fluidized bed reactor.

PubMed

Zhang, Wei; Feng, Yangyang; Chen, Yingwen; Li, Peiwen; Zhu, Shemin; Shen, Shubao

2018-02-05

In this paper, a new type of biogas jet assisted anaerobic fluidized bed reactor loaded with a polypropylene carrier has been proposed. There was a clear improvement in the fluidized state due to the biogas assisted input when the gas/water ratio was set at 1:3 with a suitable carrier loading of 60%. When the circulating water flow is 30 L/min assisted with biogas 10 L/min, the mixing time shortens from 26 to 18 s. The performance of anaerobic biodegradation on wastewater treatment was improved largely. The chemical oxygen demand (COD) and terepthallic acid removal efficiencies were at 85.4% and 84%, respectively, at hydraulic retention time of 20 h, even when the influent COD concentration was as high as 4224 mg/L. In addition, plenty of microorganisms, attached to the carriers and assumed to be the reason behind the organic biodegradation efficiency of the proposed system, were observed using scanning electron microscopy.

Effect of influent COD/SO4(2-) ratios on UASB treatment of a synthetic sulfate-containing wastewater.

PubMed

Hu, Yong; Jing, Zhaoqian; Sudo, Yuta; Niu, Qigui; Du, Jingru; Wu, Jiang; Li, Yu-You

2015-07-01

The effect of the chemical oxygen demand/sulfate (COD/SO4(2-)) ratio on the anaerobic treatment of synthetic chemical wastewater containing acetate, ethanol, and sulfate, was investigated using a UASB reactor. The experimental results show that at a COD/SO4(2-) ratio of 20 and a COD loading rate of 25.2gCODL(-1)d(-1), a COD removal of as high as 87.8% was maintained. At a COD/SO4(2-) ratio of 0.5 (sulfate concentration 6000mgL(-1)), however, the COD removal was 79.2% and the methane yield was 0.20LCH4gCOD(-1). The conversion of influent COD to methane dropped from 80.5% to 54.4% as the COD/SO4(2-) ratio decreased from 20 to 0.5. At all the COD/SO4(2-) ratios applied, over 79.4% of the total electron flow was utilized by methane-producing archaea (MPA), indicating that methane fermentation was the predominant reaction. The majority of the methane was produced by acetoclastic MPA at high COD/SO4(2-) ratios and both acetoclastic and hydrogenthrophic MPA at low COD/SO4(2-) ratios. Only at low COD/SO4(2-) ratios were SRB species such as Desulfovibrio found to play a key role in ethanol degradation, whereas all the SRB species were found to be incomplete oxidizers at both high and low COD/SO4(2-) ratios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient treatment of azo dye containing wastewater in a hybrid acidogenic bioreactor stimulated by biocatalyzed electrolysis.

PubMed

Wang, Hong-Cheng; Cheng, Hao-Yi; Wang, Shu-Sen; Cui, Dan; Han, Jing-Long; Hu, Ya-Ping; Su, Shi-Gang; Wang, Ai-Jie

2016-01-01

In this study, a novel scaled-up hybrid acidogenic bioreactor (HAB) was designed and adopted to evaluate the performance of azo dye (acid red G, ARG) containing wastewater treatment. Principally, HAB is an acidogenic bioreactor coupled with a biocatalyzed electrolysis module. The effects of hydraulic retention time (HRT) and ARG loading rate on the performance of HAB were investigated. In addition, the influent was switched from synthetic wastewater to domestic wastewater to examine the key parameters for the application of HAB. The results showed that the introduction of the biocatalyzed electrolysis module could enhance anoxic decolorization and COD (chemical oxygen demand) removal. The combined process of HAB-CASS presented superior performance compared to a control system without biocatalyzed electrolysis (AB-CASS). When the influent was switched to domestic wastewater, with an environment having more balanced nutrients and diverse organic matters, the ARG, COD and nitrogen removal efficiencies of HAB-CASS were further improved, reaching 73.3%±2.5%, 86.2%±3.8% and 93.5%±1.6% at HRT of 6 hr, respectively, which were much higher than those of AB-CASS (61.1%±4.7%, 75.4%±5.0% and 82.1%±2.1%, respectively). Moreover, larger TCV/TV (total cathode volume/total volume) for HAB led to higher current and ARG removal. The ARG removal efficiency and current at TCV/TV of 0.15 were 39.2%±3.7% and 28.30±1.48 mA, respectively. They were significantly increased to 62.1%±2.0% and 34.55±0.83 mA at TCV/TV of 0.25. These results show that HAB system could be used to effectively treat real wastewater. Copyright © 2015. Published by Elsevier B.V.

Integration of ceramic membrane and compressed air-assisted solvent extraction (CASX) for metal recovery.

PubMed

Li, Chi-Wang; Chiu, Chun-Hao; Lee, Yu-Cheng; Chang, Chia-Hao; Lee, Yu-Hsun; Chen, Yi-Ming

2010-01-01

In our previous publications, compressed air-assisted solvent extraction process (CASX) was developed and proved to be kinetically efficient process for metal removal. In the current study, CASX with a ceramic MF membrane integrated for separation of spent solvent was employed to remove and recover metal from wastewater. MF was operated either in crossflow mode or dead-end with intermittent flushing mode. Under crossflow mode, three distinct stages of flux vs. TMP (trans-membrane pressure) relationship were observed. In the first stage, flux increases with increasing TMP which is followed by the stage of stable flux with increasing TMP. After reaching a threshold TMP which is dependent of crossflow velocity, flux increases again with increasing TMP. At the last stage, solvent was pushed through membrane pores as indicated by increasing permeate COD. In dead-end with intermittent flushing mode, an intermittent flushing flow (2 min after a 10-min or a 30-min dead-end filtration) was incorporated to reduce membrane fouling by flush out MSAB accumulated on membrane surface. Effects of solvent concentration and composition were also investigated. Solvent concentrations ranging from 0.1 to 1% (w/w) have no adverse effect in terms of membrane fouling. However, solvent composition, i.e. D(2)EHPA/kerosene ratio, shows impact on membrane fouling. The type of metal extractants employed in CASX has significant impact on both membrane fouling and the quality of filtrate due to the differences in their viscosity and water solubility. Separation of MSAB was the limiting process controlling metal removal efficiency, and the removal efficiency of Cd(II) and Cr(VI) followed the same trend as that for COD.

Rapid formation and pollutant removal ability of aerobic granules in a sequencing batch airlift reactor at low temperature.

PubMed

Jiang, Yu; Shang, Yu; Wang, Hongyu; Yang, Kai

2016-12-01

The start-up of an aerobic granular sludge (AGS) reactor at low temperature was more difficult than at ambient temperature.The rapid formation and characteristics of AGS in a sequencing batch airlift reactor at low temperature were investigated. The nutrient removal ability of the system was also evaluated. It was found that compact granules with clear boundary were formed within 10 days and steady state was achieved within 25 days. The settling properties of sludge were improved with the increasing secretion of extracellular polymeric substances and removal performances of pollutants were enhanced along with granulation. The average removal efficiencies of COD, NH4(+)-N, total nitrogen (TN), total phosphorus (TP) after aerobic granules maturing were over 90.9%, 94.7%, 75.4%, 80.2%, respectively. The rise of temperature had little impact on pollutant biodegradation while the variation of dissolved oxygen caused obvious changes in TN and TP removal rates. COD concentrations of effluents were below 30 mg l(-1) in most cycles of operation with a wide range of organic loading rates (0.6-3.0 kg COD m(-3) d(-1)). The rapid granulation and good performance of pollutant reduction by the system might provide an alternate for wastewater treatment in cold regions.

Remediation of Urban River Water by Pontederia Cordata Combined with Artificial Aeration: Organic Matter and Nutrients Removal and Root-Adhered Bacterial Communities.

PubMed

Gu, Dungang; Xu, Huan; He, Yan; Zhao, Feng; Huang, Minsheng

2015-01-01

Macrophyte combined with artificial aeration is a promising in situ remediation approach for urban rivers polluted with nutrients and organic matter. However, seasonal variations and aeration effects on phytoremediation performance and root-adhered microbial communities are still unclear. In this study, Pontederia cordata was used to treat polluted urban river water under various aeration intensities. Results showed that the highest removal efficiencies of chemical oxygen demand (COD(Cr)) and total nitrogen (TN) were attained under aeration of 30 L min(-1) in spring and summer and 15 L min(-1) in autumn, while total phosphorus (TP) removal reached maximum with aeration of 15 L min(-1) in all seasons. Moderate aeration was beneficial for increasing the diversity of root-adhered bacteria communities, and the shift of bacterial community structure was more pronounced in spring and autumn with varying aeration intensity. The dual effect, i.e. turbulence and dissolved oxygen (DO), of aeration on the removal of COD(Cr) and TN prevailed over the individual effect of DO, while DO was the most influential factor for TP removal and the root-adhered bacterial community diversity. P. cordata combined with 15 L min(-1) aeration was deemed to be the best condition tested in this study.

Submerged anaerobic membrane bioreactor for wastewater treatment and energy generation.

PubMed

Bornare, J B; Adhyapak, U S; Minde, G P; Kalyan Raman, V; Sapkal, V S; Sapkal, R S

2015-01-01

Compared with conventional wastewater treatment processes, membrane bioreactors (MBRs) offer several advantages including high biodegradation efficiency, excellent effluent quality and smaller footprint. However, it has some limitations on account of its energy intensive operation. In recent years, there has been growing interest in use of anaerobic membrane bioreactors (AnMBRs) due to their potential advantages over aerobic systems, which include low sludge production and energy generation in terms of biogas. The aim of this study was to evaluate the performance of a submerged AnMBR for the treatment of synthetic wastewater having 4,759 mg/l chemical oxygen demand (COD). The COD removal efficiency was over 95% during the performance evaluation study. Treated effluent with COD concentration of 231 mg/l was obtained for 25.5 hours hydraulic retention time. The obtained total organic carbon concentrations in feed and permeate were 1,812 mg/l and 89 mg/l, respectively. An average biogas generation and yield were 25.77 l/d and 0.36 m3/kg COD, respectively. Evolution of trans-membrane pressure (TMP) as a function of time was studied and an average TMP of 15 kPa was found suitable to achieve membrane flux of 12.17 l/(m2h). Almost weekly back-flow chemical cleaning of the membrane was found necessary to control TMP within the permissible limit of 20 kPa.

Bioelectricity generation using two chamber microbial fuel cell treating wastewater from food processing.

PubMed

Mansoorian, Hossein Jafari; Mahvi, Amir Hossein; Jafari, Ahmad Jonidi; Amin, Mohammad Mehdi; Rajabizadeh, Ahmad; Khanjani, Narges

2013-05-10

Electricity generation from microbial fuel cells which treat food processing wastewater was investigated in this study. Anaerobic anode and aerobic cathode chambers were separated by a proton exchange membrane in a two-compartment MFC reactor. Buffer solutions and food industry wastewater were used as electrolytes in the anode and cathode chambers, respectively. The produced voltage and current intensity were measured using a digital multimeter. Effluents from the anode compartment were tested for COD, BOD5, NH3, P, TSS, VSS, SO4 and alkalinity. The maximum current density and power production were measured 527mA/m(2) and 230mW/m(2) in the anode area, respectively, at operation organic loading (OLR) of 0.364g COD/l.d. At OLR of 0.182g COD/l.d, maximum voltage and columbic efficiency production were recorded 0.475V and 21%, respectively. Maximum removal efficiency of COD, BOD5, NH3, P, TSS, VSS, SO4 and alkalinity were 86, 79, 73, 18, 68, 62, 30 and 58%, respectively. The results indicated that catalysts and mediator-less microbial fuel cells (CAML-MFC) can be considered as a better choice for simple and complete energy conversion from the wastewater of such industries and also this could be considered as a new method to offset wastewater treatment plant operating costs. Copyright © 2013 Elsevier Inc. All rights reserved.

A comparative study of the treatment of ethylene plant spent caustic by neutralization and classical and advanced oxidation.

PubMed

Hawari, Alaa; Ramadan, Hasanat; Abu-Reesh, Ibrahim; Ouederni, Mabrouk

2015-03-15

The treatment of spent caustic produced from an ethylene plant was investigated. In the case of neutralization alone it was found that the maximum removal of sulfide was at pH values below 5.5. The higher percentage removal of sulfides (99% at pH = 1.5) was accompanied with the highest COD removal (88%). For classical oxidation using H2O2 the maximum COD removal percentage reached 89% at pH = 2.5 and at a hydrogen peroxide concentration of 19 mM/L. For the advanced oxidation using Fenton's process it was found that the maximum COD removal of 96.5% was achieved at a hydrogen peroxide/ferrous sulfate ratio of (7:1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical oxidation for mitigation of UV-quenching substances (UVQS) from municipal landfill leachate: Fenton process versus ozonation.

PubMed

Jung, Chanil; Deng, Yang; Zhao, Renzun; Torrens, Kevin

2017-01-01

UV-quenching substance (UVQS), as an emerging municipal solid waste (MSW)-derived leachate contaminant, has a potential to interfere with UV disinfection when leachate is disposed of at publicly owned treatment works (POTWs). The objective of this study was to evaluate and compare two chemical oxidation processes under different operational conditions, i.e. Fenton process and ozonation, for alleviation of UV 254 absorbance of a biologically pre-treated landfill leachate. Results showed that leachate UV 254 absorbance was reduced due to the UVQS decomposition by hydroxyl radicals (·OH) during Fenton treatment, or by ozone (O 3 ) and ·OH during ozonation. Fenton process exhibited a better treatment performance than ozonation under their respective optimal conditions, because ·OH could effectively decompose both hydrophobic and hydrophilic dissolved organic matter (DOM), but O 3 tended to selectively oxidize hydrophobic compounds alone. Different analytical techniques, including molecular weight (MW) fractionation, hydrophobic/hydrophilic isolation, UV spectra scanning, parallel factor (PARAFAC) analysis, and fluorescence excitation-emission matrix spectrophotometry, were used to characterize UVQS. After either oxidation treatment, residual UVQS was more hydrophilic with a higher fraction of low MW molecules. It should be noted that the removed UV 254 absorbance (ΔUV 254 ) was directly proportional to the removed COD (ΔCOD) for the both treatments (Fenton process: ΔUV 254  = 0.011ΔCOD; ozonation: ΔUV 254  = 0.016ΔCOD). A greater ΔUV 254 /ΔCOD was observed for ozonation, suggesting that oxidant was more efficiently utilized during ozonation than in Fenton treatment for mitigation of the UV absorbance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of the organic loading rate on the performance and the granular sludge characteristics of an EGSB reactor used for treating traditional Chinese medicine wastewater.

PubMed

Li, Weiguang; Su, Chengyuan; Liu, Xingzhe; Zhang, Lei

2014-01-01

The effects of the organic loading rate (OLR) on the performance and the granular sludge characteristics of an expanded granular sludge bed (EGSB) reactor used for treating real traditional Chinese medicine (TCM) wastewater were investigated. Over 90% of the COD removal by the EGSB reactor was observed at the OLRs of 4 to 13 kg COD/(m(3) day). However, increasing the OLR to 20 kg COD/(m(3) day) by reducing the hydraulic retention time (HRT 6 h) reduced the COD removal efficiency to 78%. The volatile fatty acid (VFA) concentration was 512.22 mg/L, resulting in an accumulation of VFAs, and propionic acid was the main acidification product, accounting for 66.51% of the total VFAs. When the OLR increased from 10 to 20 kg COD/(m(3) day), the average size of the granule sludge decreased from 469 to 258 μm. There was an obvious reduction in the concentration of Ca(2+) and Mg(2+) in the granular sludge. The visible humic acid-like peak was identified in the three-dimensional excitation-emission matrix (EEM) fluorescence spectra of the soluble microbial products (SMPs). The fatty acid bond, amide II bond, amide III bond, and C-H bond bending were also observed in the Fourier transform infrared (FTIR) spectra of the SMPs. Methanobacterium formicicum, Methanococcus, and Bacteria populations exhibited significant shifts, and these changes were accompanied by an increase in VFA production. The results indicated that a short HRT and high OLR in the EGSB reactor caused the accumulation of polysaccharides, protein, and VFAs, thereby inhibiting the activity of methanogenic bacteria and causing granular sludge corruption.