Biodegradation kinetics of thin-stillage treatment by Aspergillus awamori and characterization of recovered chitosan.

PubMed

Ray, S Ghosh; Ghangrekar, M M

2016-02-01

An attempt has been made to provide solution for distillery wastewater using fungal pretreatment followed by an anaerobic process to achieve higher organic matter removal, which is a challenge at present with currently adopted technologies. Submerged growth kinetics of distillery wastewater supernatant by Aspergillus awamori was also evaluated. The proposed kinetic models using a logistic equation for fungal growth and the Leudeking-Piret equation for product formation were validated experimentally, and substrate consumption equation was derived using estimated kinetic coefficients. Up to 59.6 % chemical oxygen demand (COD) and 70 % total organic carbon (TOC) removals were observed in 96 h of fungal incubation. Maximum specific growth rate of fungi, coefficient of biomass yield on substrate and growth-associated product formation coefficient were estimated to be 0.07 ± 0.01 h(-1), 0.614 kg biomass/kg utilized COD and 0.215 kg CO2/kg utilized TOC, respectively. The chitosan recovery of 0.072-0.078 kg/kg of dry mycelium was obtained using dilute sulphuric acid extraction, showing high purity and characteristic chitosan properties according to FTIR and XRD analyses. After anaerobic treatment of the fungal pretreated effluent with COD concentration of 7.920 ± 0.120 kg COD/m(3) (organic loading rate of 3.28 kg COD/m(3) day), overall COD reduction of 91.07 % was achieved from distillery wastewater.

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.

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.

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.

Lipid and fatty acid compositions of cod ( Gadus morhua), haddock ( Melanogrammus aeglefinus) and halibut ( Hippoglossus hippoglossus)

NASA Astrophysics Data System (ADS)

Zeng, Duan; Mai, Kangsen; Ai, Qinghui; Milley, Joyce E.; Lall, Santosh P.

2010-12-01

This study was conducted to compare lipid and fatty acid composition of cod, haddock and halibut. Three groups of cod (276 g ± 61 g), haddock (538 g ± 83 g) and halibut (3704 g ± 221 g) were maintained with commercial feeds mainly based on fish meal and marine fish oil for 12 weeks prior to sampling. The fatty acid compositions of muscle and liver were determined by GC/FID after derivatization of extracted lipids into fatty acid methyl esters (FAME). Lipids were also fractionated into neutral and polar lipids using Waters silica Sep-Pak?. The phospholipid fraction was further separated by high-performance thin-layer chromatography (HPTLC) and the FAME profile was obtained. Results of the present study showed that cod and haddock were lean fish and their total muscle lipid contents were 0.8% and 0.7%, respectively, with phospholipid constituting 83.6% and 87.5% of the total muscle lipid, respectively. Halibut was a medium-fat fish and its muscle lipid content was 8%, with 84% of the total muscle lipid being neutral lipid. Total liver lipid contents of cod, haddock and halibut were 36.9%, 67.2% and 30.7%, respectively, of which the neutral lipids accounted for the major fraction (88.1%-97.1%). Polyunsaturated fatty acids were the most abundant in cod and haddock muscle neutral lipid. Monounsaturated fatty acid level was the highest in halibut muscle neutral lipid. Fatty acid compositions of phospholipid were relatively constant. In summary, the liver of cod and haddock as lean fish was the main lipid reserve organ, and structural phospholipid is the major lipid form in flesh. However, as a medium-fat fish, halibut stored lipid in both their liver and muscle.

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

Relationships between water quality parameters in rivers and lakes: BOD5, COD, NBOPs, and TOC.

PubMed

Lee, Jaewoong; Lee, Seunghyun; Yu, Soonju; Rhew, Doughee

2016-04-01

Biological oxygen demand (BOD5) or chemical oxygen demand (COD) analysis is widely used to evaluate organic pollutants in water systems as well as the efficiency of wastewater treatment plants. However, both analysis methods have restrictions such as being insensitive, imprecise, time-consuming, and the production of chemical waste. Therefore, total organic carbon (TOC) analysis for organic pollutants has been considered for an alternative analysis instead of BOD5 or COD. Several studies have investigated the replacement of BOD5 or COD with TOC in wastewater samples; however, few studies have investigated the relationships between water quality parameters in rivers and lakes. Therefore, this study evaluated the relationships between BOD5, COD, or NBOPs and TOC by the analysis of national water quality monitoring data of rivers and lakes for 5 years. High correlation coefficients (r) of 0.87 and 0.66 between BOD5 and TOC (p < 0.05) were obtained for rivers and lakes, respectively, and strong correlation coefficients (r) of 0.93 and 0.75 were observed between COD and TOC (p < 0.05) for rivers and lakes, respectively. The correlation coefficient (r) between NBOPs and TOC was 0.93 for rivers and 0.72 for lakes. The coefficients of determination (R 2) were 0.75 and 0.44 between BOD5 and TOC for rivers and lakes as well as were 0.87 and 0.57 between COD and TOC for rivers and lakes, respectively. The coefficient of determination (R 2) between NBOPs and TOC was 0.73 for rivers and 0.52 for lakes.

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.

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.

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.

Organic matter degradation in a greywater recycling system using a multistage moving bed biofilm reactor (MBBR).

PubMed

Saidi, Assia; Masmoudi, Khaoula; Nolde, Erwin; El Amrani, Btissam; Amraoui, Fouad

2017-12-01

Greywater is an important non-conventional water resource which can be treated and recycled in buildings. A decentralized greywater recycling system for 223 inhabitants started operating in 2006 in Berlin, Germany. High load greywater undergoes advanced treatment in a multistage moving bed biofilm reactor (MBBR) followed by sand filtration and UV disinfection. The treated water is used safely as service water for toilet flushing. Monitoring of the organic matter degradation was pursued to describe the degradation processes in each stage and optimize the system. Results showed that organic matter reduction was achieved for the most part in the first three reactors, whereas the highest reduction rate was observed in the third reactor in terms of COD (chemical oxygen demand), dissolved organic carbon and BOD 7 (biological oxygen demand). The results also showed that the average loading rate entering the system was 3.7 kg COD/d, while the removal rate was 3.4 kg COD/d in a total bioreactor volume of 11.7 m³. In terms of BOD, the loading rate was 2.8 kg BOD/d and it was almost totally removed. This system requires little space (0.15 m²/person) and maintenance work of less than one hour per month and it shows operational stability under peak loads.

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.

Treatment of olive mill wastewater by chemical processes: effect of acid cracking pretreatment.

PubMed

Hande Gursoy-Haksevenler, B; Arslan-Alaton, Idil

2014-01-01

The effect of acid cracking (pH 2.0; T 70 °C) and filtration as a pretreatment step on the chemical treatability of olive mill wastewater (chemical oxygen demand (COD) 150,000 m/L; total organic carbon (TOC) 36,000 mg/L; oil-grease 8,200 mg/L; total phenols 3,800 mg/L) was investigated. FeCl3 coagulation, Ca(OH)2 precipitation, electrocoagulation using stainless steel electrodes and the Fenton's reagent were applied as chemical treatment methods. Removal performances were examined in terms of COD, TOC, oil-grease, total phenols, colour, suspended solids and acute toxicity with the photobacterium Vibrio fischeri. Significant oil-grease (95%) and suspended solids (96%) accompanied with 58% COD, 43% TOC, 39% total phenols and 80% colour removals were obtained by acid cracking-filtration pretreatment. Among the investigated chemical treatment processes, electrocoagulation and the Fenton's reagent were found more effective after pretreatment, especially in terms of total phenols removal. Total phenols removal increased from 39 to 72% when pretreatment was applied, while no significant additional (≈10-15%) COD and TOC removals were obtained when acid cracking was coupled with chemical treatment. The acute toxicity of the original olive mill wastewater sample increased considerably after pretreatment from 75 to 89% (measured for the 10-fold diluted wastewater sample). An operating cost analysis was also performed for the selected chemical treatment processes.

Comparative study on treatment of kitchen wastewater using a mixed microalgal culture and an aerobic bacterial culture: kinetic evaluation and FAME analysis.

PubMed

Katam, Keerthi; Bhattacharyya, Debraj

2018-05-12

Microalgae-based treatment systems have been successfully used for the polishing of domestic wastewater. Research is underway in studying the suitability of using these systems as main treatment units. This study focuses on comparing the performances of a mixed microalgal culture and an aerobic bacterial culture, based on the kinetic evaluation, in removing organic carbon from a kitchen wastewater. The two systems were operated at six different solid retention times (SRTs)-2, 4, 6, 8, 10, and 12 days in continuous mode. The influent and effluent samples were analyzed for chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen (TN), phosphates, and surfactants. Steady-state kinetics (k, K s , Y, and k d ) for organic carbon removal were obtained by fitting experimental data in linearized Michaelis-Menten and Monod equations. The mixed microalgal system showed similar or better performance in COD and TN removal (88 and 85%, respectively) when compared with the COD and TN removal by the aerobic bacterial system (89 and 48%). A maximum lipid yield of 40% (w/w of dry biomass) was observed in the microalgal system. Saturated fatty acids accounted for 50% of the total observed FAME species. The study indicates that the mixed microalgal culture is capable of treating kitchen wastewater and has the potential to replace aerobic bacteria in biological treatment systems in certain cases.

Systematic comparison of mechanical and thermal sludge disintegration technologies.

PubMed

Wett, B; Phothilangka, P; Eladawy, A

2010-06-01

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis. Copyright 2009 Elsevier Ltd. All rights reserved.

Organics removal of combined wastewater through shallow soil infiltration treatment: a field and laboratory study.

PubMed

Zhang, Zhiyin; Lei, Zhongfang; Zhang, Zhenya; Sugiura, Norio; Xu, Xiaotian; Yin, Didi

2007-11-19

Soil infiltration treatment (SIT) was proved to be an effective and low-cost treatment technique for decentralized effluents in the areas without perfect sewage systems. Field-scale experiments were conducted under several conditions to assess organics removals through a shallow soil infiltration treatment (SSIT, with effective depth 0.3m) of combined wastewater (discharge from toilets, restaurants and a gas station), while bench-scale soil column experiments were performed in laboratory in parallel to investigate biological and abiological effects of this kind of system. From the start-up to the 10th month, the field SSIT trenches experienced the lowest and highest temperatures of the operation period in Shanghai and exhibited effective organics removals after maturation, with the highest removal rate 75.8% of chemical oxygen demand (COD), highest ultraviolet absorption at 254 nm (UV(254)) decrease by 67.2% and 35.2-100% removals of phenolic and phthalate pollutants. The laboratory results indicated that more organics could be removed in room-temperatured (25+/-2 degrees C) SSIT systems under different influent COD concentrations from 45 mg/l to 406 mg/l, and the highest total COD removal rate could reach 94.0%, in which biological effect accounted for 57.7-71.9%. The results showed that temperature and hydraulic loading rate were the most important factors influencing the removals of COD and organic pollutants in SSIT.

A combined upflow anaerobic sludge bed and trickling biofilter process for the treatment of swine wastewater.

PubMed

Zhao, Bowei; Li, Jiangzheng; Buelna, Gerardo; Dubé, Rino; Le Bihan, Yann

2016-01-01

A combined upflow anaerobic sludge blanket (UASB)-trickling biofilter (TBF) process was constructed to treat swine wastewater, a typical high-strength organic wastewater with low carbon/nitrogen ratio and ammonia toxicity. The results showed that the UASB-TBF system can remarkably enhance the removal of pollutants in the swine wastewater. At an organic loading rate of 2.29 kg/m(3) d and hydraulic retention time of 48 h in the UASB, the chemical oxygen demand (COD), Suspended Solids and Total Kjeldahl Nitrogen removals of the combined process reached 83.6%, 84.1% and 41.2%, respectively. In the combined system the UASB served as a pretreatment process for COD removal while nitrification and denitrification occurred only in the TBF process. The TBF performed reasonably well at a surface hydraulic load as high as 0.12 m(3)/m(2) d. Since the ratio of influent COD to total mineral nitrogen was less than 3.23, it is reasonable to suggest that the wood chips in TBF can serve as a new carbon source for denitrification.

Biodegradability of fluorinated fire-fighting foams in water.

PubMed

Bourgeois, A; Bergendahl, J; Rangwala, A

2015-07-01

Fluorinated fire-fighting foams may be released into the environment during fire-fighting activities, raising concerns due to the potential environmental and health impacts for some fluorinated organics. The current study investigated (1) the biodegradability of three fluorinated fire-fighting foams, and (2) the applicability of current standard measures used to assess biodegradability of fluorinated fire-fighting foams. The biodegradability of three fluorinated fire-fighting foams was evaluated using a 28-day dissolved organic carbon (DOC) Die-Away Test. It was found that all three materials, diluted in water, achieved 77-96% biodegradability, meeting the criteria for "ready biodegradability". Defluorination of the fluorinated organics in the foam during biodegradation was measured using ion chromatography. It was found that the fluorine liberated was 1-2 orders of magnitude less than the estimated initial amount, indicating incomplete degradation of fluorinated organics, and incomplete CF bond breakage. Published biodegradability data may utilize biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC) metrics to quantify organics. COD and TOC of four fluorinated compounds were measured and compared to the calculated carbon content or theoretical oxygen demand. It was found that the standard dichromate-based COD test did not provide an accurate measure of fluorinated organic content. Thus published biodegradability data using COD for fluorinated organics quantification must be critically evaluated for validity. The TOC measurements correlated to an average of 91% of carbon content for the four fluorinated test substances, and TOC is recommended for use as an analytical parameter in fluorinated organics biodegradability tests. Copyright © 2015 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.

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.

Benchmarking of municipal waste water treatment plants (an Austrian project).

PubMed

Lindtner, S; Kroiss, H; Nowak, O

2004-01-01

An Austrian research project focused on the development of process indicators for treatment plants with different process and operation modes. The whole treatment scheme was subdivided into four processes, i.e. mechanical pretreatment (Process 1), mechanical-biological waste water treatment (Process 2), sludge thickening and stabilisation (Process 3) and further sludge treatment and disposal (Process 4). In order to get comparable process indicators it was necessary to subdivide the sample of 76 individual treatment plants all over Austria into five groups according to their mean organic load (COD) in the influent. The specific total yearly costs, the yearly operating costs and the yearly capital costs of the four processes have been related to the yearly average of the measured organic load expressed in COD (110 g COD/pe/d). The specific investment costs for the whole treatment plant and for Process 2 have been related to a calculated standard design capacity of the mechanical-biological part of the treatment plant expressed in COD. The capital costs of processes 1, 3 and 4 have been related to the design capacity of the treatment plant. For each group (related to the size of the plant) a benchmark band has been defined for the total yearly costs, the total yearly operational costs and the total yearly capital costs. For the operational costs of the Processes 1 to 4 one benchmark ([see symbol in text] per pe/year) has been defined for each group. In addition a theoretical cost reduction potential has been calculated. The cost efficiency in regard to water protection and some special sub-processes such as aeration and sludge dewatering has been analysed.

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.

Evaluation of multivariate linear regression and artificial neural networks in prediction of water quality parameters

PubMed Central

2014-01-01

This paper examined the efficiency of multivariate linear regression (MLR) and artificial neural network (ANN) models in prediction of two major water quality parameters in a wastewater treatment plant. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) as well as indirect indicators of organic matters are representative parameters for sewer water quality. Performance of the ANN models was evaluated using coefficient of correlation (r), root mean square error (RMSE) and bias values. The computed values of BOD and COD by model, ANN method and regression analysis were in close agreement with their respective measured values. Results showed that the ANN performance model was better than the MLR model. Comparative indices of the optimized ANN with input values of temperature (T), pH, total suspended solid (TSS) and total suspended (TS) for prediction of BOD was RMSE = 25.1 mg/L, r = 0.83 and for prediction of COD was RMSE = 49.4 mg/L, r = 0.81. It was found that the ANN model could be employed successfully in estimating the BOD and COD in the inlet of wastewater biochemical treatment plants. Moreover, sensitive examination results showed that pH parameter have more effect on BOD and COD predicting to another parameters. Also, both implemented models have predicted BOD better than COD. PMID:24456676

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.

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.

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.

Optimization of the photoelectrocatalytic oxidation of landfill leachate using copper and nitrate co-doped TiO2 (Ti) by response surface methodology

PubMed Central

Zhou, Shaoqi; Feng, Xinbin

2017-01-01

In this paper, a statistically-based experimental design with response surface methodology (RSM) was employed to examine the effects of functional conditions on the photoelectrocatalytic oxidation of landfill leachate using a Cu/N co-doped TiO2 (Ti) electrode. The experimental design method was applied to response surface modeling and the optimization of the operational parameters of the photoelectro-catalytic degradation of landfill leachate using TiO2 as a photo-anode. The variables considered were the initial chemical oxygen demand (COD) concentration, pH and the potential bias. Two dependent parameters were either directly measured or calculated as responses: chemical oxygen demand (COD) removal and total organic carbon (TOC) removal. The results of this investigation reveal that the optimum conditions are an initial pH of 10.0, 4377.98mgL-1 initial COD concentration and 25.0 V of potential bias. The model predictions and the test data were in satisfactory agreement. COD and TOC removals of 67% and 82.5%, respectively, were demonstrated. Under the optimal conditions, GC/MS showed 73 organic micro-pollutants in the raw landfill leachate which included hydrocarbons, aromatic compounds and esters. After the landfill leachate treatment processes, 38 organic micro-pollutants disappeared completely in the photoelectrocatalytic process. PMID:28671943

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.

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

Ultrasound assisted biogas production from landfill leachate

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

Oz, Nilgün Ayman, E-mail: nilgunayman@comu.edu.tr; Yarimtepe, Canan Can

Highlights: • Effect of low frequency ultrasound pretreatment on leachate was investigated. • Three different ultrasound energy inputs (200, 400 and 600 W/l) was applied. • Low-frequency ultrasound treatment increased soluble COD in landfill leachate. • Application of ultrasound to leachate increased biogas production about 40%. • Application of ultrasound to leachate increased total methane production rate about 20%. - Abstract: The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions formore » solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45 min sonication at 600 W/l. Non-parametric Friedman’s test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p < 0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann–Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p < 0.05) in anaerobic batch reactors. The overall results showed that low frequency ultrasound pretreatment can be potentially used for wastewater management especially with integration of anaerobic processes.« less

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.

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.

Use of COD, TOC, and Fluorescence Spectroscopy to Estimate BOD in Wastewater.

PubMed

Christian, Evelyn; Batista, Jacimaria R; Gerrity, Daniel

2017-02-01

  Common to all National Pollutant Discharge Elimination System (NPDES) permits in the United States is a limit on biochemical oxygen demand (BOD). Chemical oxygen demand (COD), total organic carbon (TOC), and fluorescence spectroscopy are also capable of quantifying organic content, although the mechanisms of quantification and the organic fractions targeted differ for each test. This study explores correlations between BOD5 and these alternate test procedures using facility influent, primary effluent, and facility effluent samples from a full-scale water resource recovery facility. Relative reductions of the water quality parameters proved to be strong indicators of their suitability as surrogates for BOD5. Suitable correlations were generally limited to the combined datasets for the three sampling locations or the facility effluent alone. COD exhibited relatively strong linear correlations with BOD5 when considering the three sample points (r = 0.985) and the facility effluent alone (r = 0.914), while TOC exhibited a suitable linear correlation with BOD5 in the facility effluent (r = 0.902). Exponential regressions proved to be useful for estimating BOD5 based on TOC or fluorescence (r > 0.95).

Effect of temperature on methanogenesis stage of two-stage anaerobic digestion of palm oil mill effluent (POME) into biogas

NASA Astrophysics Data System (ADS)

Trisakti, B.; Irvan, Mahdalena; Taslim; Turmuzi, M.

2017-06-01

This study aimed to determine the effect of temperature on methanogenesis stage of conversion of palm oil mill effluent into biogas. Methanogenesis is the second stage of methanogenic anaerobic digestion. Improved performance of the methanogenesis process was determined by measuring the growth of microorganisms, degradation of organic materials, biogas production and composition. Initially, the suitable loading up was determined by varying the HRT 100, 40, 6, and 4.0 days in the continuous stirred tank reactor (CSTR) with mixing rate 100 rpm, pH 6.7-7.5 at room temperature. Next, effect of temperature on the process was determined by varying temperature at mesophilic range (30-42°C) and thermophilic range (43-55°C). Analysis of total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (VSS), and chemical oxygen demand (COD) were conducted in order to study the growth of microorganisms and their abilities in converting organic compound to produce biogas. Degradation of organic content i.e. VS decomposition and COD removal increased with the increasing of temperature. At mesophilic range, VS decomposition and COD removal were 51.56 ± 8.30 and 79.82 ± 6.03, respectively. Meanwhile at thermopilic range, VS decomposition and COD removal were 67.44 ± 3.59 and 79.16 ± 1.75, respectively. Biogas production and its methane content also increased with the increasing of temperature, but CO2 content also increased. Biogas production at mesophilic range was 31.77 ± 3.46 L/kg-ΔVS and methane content was 75 . Meanwhile, biogas production at thermopilic range was 37.03 ± 5.16 L/kg-ΔVS and methane content was 62.25 ± 5.50 .

Breakdown of food waste by anaerobic fermentation and non-oxygen producing photosynthesis using a photosynthetic bacterium.

PubMed

Mekjinda, N; Ritchie, R J

2015-01-01

Large volumes of food waste are produced by restaurants, hotels, etc generating problems in its collection, processing and disposal. Disposal as garbage increases the organic matter in landfills and leachates. The photosynthetic bacterium Rhodopseudomonas palustris (CGA 009) easily broke down food waste. R. palustris produces H2 under anaerobic conditions and digests a very wide range of organic compounds. R. palustris reduced BOD by ≈70% and COD by ≈33%, starch, ammonia, nitrate, was removed but had little effect on reducing sugar or the total phosphorus, lipid, protein, total solid in a 7-day incubation. R. palustris produced a maximum of 80ml H2/g COD/day. A two-stage anaerobic digestion using yeast as the first stage, followed by a R. palustris digestion was tested but production of H2 was low. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prediction of BOD, COD, and total nitrogen concentrations in a typical urban river using a fluorescence excitation-emission matrix with PARAFAC and UV absorption indices.

PubMed

Hur, Jin; Cho, Jinwoo

2012-01-01

The development of a real-time monitoring tool for the estimation of water quality is essential for efficient management of river pollution in urban areas. The Gap River in Korea is a typical urban river, which is affected by the effluent of a wastewater treatment plant (WWTP) and various anthropogenic activities. In this study, fluorescence excitation-emission matrices (EEM) with parallel factor analysis (PARAFAC) and UV absorption values at 220 nm and 254 nm were applied to evaluate the estimation capabilities for biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total nitrogen (TN) concentrations of the river samples. Three components were successfully identified by the PARAFAC modeling from the fluorescence EEM data, in which each fluorophore group represents microbial humic-like (C1), terrestrial humic-like organic substances (C2), and protein-like organic substances (C3), and UV absorption indices (UV(220) and UV(254)), and the score values of the three PARAFAC components were selected as the estimation parameters for the nitrogen and the organic pollution of the river samples. Among the selected indices, UV(220), C3 and C1 exhibited the highest correlation coefficients with BOD, COD, and TN concentrations, respectively. Multiple regression analysis using UV(220) and C3 demonstrated the enhancement of the prediction capability for TN.

Treatment of spent wash in anaerobic mesophilic suspended growth reactor (AMSGR).

PubMed

Banu, J Rajesh; Kaliappan, S; Rajkumar, M; Beck, Dieter

2006-01-01

Approximately 400 KL of spent wash or vinasse per annum is generated at an average COD concentration of 100,000 mg/l, by over 250 distilleries in India. There is an urgent need to develop, assess and use ecofriendly methods for the disposal of this high strength wastewater. Therefore, an attempt was made to investigate a few aspects of anaerobic digestion of spent wash collected from a distillery. The study was carried out in a 4 L laboratory scale anaerobic mesophilic suspended growth reactor. After the successful startup, the organic loading was increased stepwise to assess the performance of the reactor. During the study period, biogas generated was recorded and the maximum gas generated was found to be 16.9 L at an Organic Loading Rate (OLR) of 38 g COD/L. A 500% increase in the Volatile Fatty Acid (VFA) concentration (2150 mg/L) was observed, when the OLR was increased from 38 to 39 g COD/L. During the souring phase the removal of COD, Total Solids (TS) and Volatile Solids (VS) were in the order of 52%, 40% and 46% respectively. The methane content in the biogas varied from 65% to 75%.

[Comparison of ciliate diversity in biodisc reactors which purify industrial wastewater].

PubMed

Luna-Pabello, V M; Durán De Bazúa, C; Aladro-Lubel, M A

1995-01-01

The comparative study of the ciliate populations present in rotating biological reactors (biodiscs reactors) of 20 l working volume, treating three different wastewaters is the aim of this project. Wastewaters chosen were those of a maize mill, of a sugarcane/ethyl alcohol plant, and of a recycled paper mill. Its dissolved organic contents, measured as soluble chemical oxygen demand (COD) and five-day biochemical oxygen demand (BOD5), were 2040 mg COD/l and 585 mg BOD5/l for maize mill effluents (nejayote), 2000 mg COD/l and 640 mg BOD5/l for sugarcane/ethanol effluents (vinasses), and 960 mg COD/l and 120 mg BOD5/l for whitewaters of the paper industry. Results obtained indicate that ciliate proliferate in all chambers of reactors treating these wastewaters. The ciliates were more abundant in vinasses, followed by nejayote, and then whitewaters. Among protozoa, ciliates were present as follows: 19 species in total. Three of them were common for the three systems. Free swimming ciliates were in higher proportion than pedunculated ones. Its diversity was higher for the whitewaters system, next for nejayote, and the lesser, for vinasses, corroborating the fact that less polluted waters have higher organisms' diversity.

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.

Effects of psychrophilic storage on manures as substrate for anaerobic digestion.

PubMed

Bergland, Wenche; Dinamarca, Carlos; Bakke, Rune

2014-01-01

The idea that storage can enhance manure quality as substrate for anaerobic digestion (AD) to recover more methane is evaluated by studying storage time and temperature effects on manure composition. Volatile fatty acids (VFA) and total dissolved organics (CODs) were measured in full scale pig manure storage for a year and in multiple flasks at fixed temperatures, mainly relevant for colder climates. The CODs generation, influenced by the source of the pig manure, was highest initially (0.3 g COD L(-1)d(-1)) gradually dropping for 3 months towards a level of COD loss by methane production at 15°C. Methane emission was low (<0.01 g COD L(-1)d(-1)) after a brief initial peak. Significant CODs generation was obtained during the warmer season (T > 10°C) in the full scale storage and almost no generation at lower temperatures (4-6°C). CODs consisted mainly of VFA, especially acetate. All VFAs were present at almost constant ratios. The naturally separated manure middle layer without sediment and coarser particles is suitable for sludge bed AD and improved further during an optimal storage time of 1-3 month(s). This implies that high rate AD can be integrated with regular manure slurry handling systems to obtain efficient biogas generation.

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.

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).

Application and advantages of novel clay ceramic particles (CCPs) in an up-flow anaerobic bio-filter (UAF) for wastewater treatment.

PubMed

Han, Wei; Yue, Qinyan; Wu, Suqing; Zhao, Yaqin; Gao, Baoyu; Li, Qian; Wang, Yan

2013-06-01

Utilization of clay ceramic particles (CCPs) as the novel filter media employed in an up-flow anaerobic bio-filter (UAF) was investigated. After a series of tests and operations, CCPs have presented higher total porosity and roughness, meanwhile lower bulk and grain density. When CCPs were utilized as fillers, the reactor had a shorter start up period of 45 days comparing with conventional reactors, and removal rate of chemical oxygen demand (COD) still reached about 76% at a relatively lower temperature during the stable state. In addition, degradation of COD and ammonia nitrogen (NH4-N) at different media height along the reactor was evaluated, and the dates showed that the main reduction process happened within the first 30 cm media height from the bottom flange. Five phases were observed according to different organic loadings during the experiment period, and the results indicated that COD removal increased linearly when the organic loading was increased. Copyright © 2013 Elsevier Ltd. All rights reserved.

Municipal-wastewater treatment using upflow-anaerobic filters.

PubMed

Manariotis, loannis D; Grigoropoulos, Sotirios G

2006-03-01

Three 12.5-L upflow-anaerobic filters (AF), with ceramic-saddle, plastic-ring, and crushed-stone packing, were used to evaluate the sustained treatment of municipal wastewater. The reactors were initially fed dogfood-fortified wastewater and then raw municipal wastewater, and operated at 25.4 degrees C (32 months) and 15.5 degrees C (2 months). During 23 months, the AF units treated municipal wastewater (mean chemical oxygen demand [COD] 442 mg/L and total suspended solids [TSS] 247 mg/L), the hydraulic retention time (HRT) ranged from 3.1 to 0.30 d (empty bed), and the organic loading rate ranged from 0.115 to 1.82 kg COD/m3d. At the higher temperature and an HRT (void volume) of 1.0 d, COD and TSS removals ranged from 74 to 79% and 95 to 96%, respectively; however, efficiencies declined substantially at HRT values less than 0.4 d. Reactor performance, under the same hydraulic and organic loadings, deteriorated with time and was adversely affected by lower temperature.

Effects of step-feeding and intermittent aeration on organics and nitrogen removal in a horizontal subsurface flow constructed wetland.

PubMed

Patil, Sagar; Chakraborty, Saswati

2017-03-21

The effect of step feed strategy and intermittent aeration on removal of chemical oxygen demand (COD) and nitrogen was investigated in a laboratory scale horizontal subsurface flow constructed wetland (HSSFCW). Wetland was divided into four zones along the length (zone I to IV), and influent was introduced into first and third zones by step feeding. Continuous study was carried out in four phases. In phases I to III, 30% of influent was bypassed to zone III for denitrification along with organics removal. Intermittent aeration was provided only in zone II at 2.5 L/min for 4 h/day, during phases II, III and IV. In phase I, 87% COD and 43% NH 4 + -N (ammonia-nitrogen) removal were obtained from influents of 331 and 30 mg/L, respectively. In phase II study, external aeration resulted in 97% COD and 71% NH 4 + -N removal in the wetland. In phase IV, 40% of feed was delivered to zone III. Higher supply of organic in zone III resulted in higher denitrification, and total nitrogen removal rate increased to 70% from 56%. In the final effluent, concentration of NO 3 - -N was 9-11 mg/L in phase I to III and decreased to 4 mg/L in phase IV. Batch study showed that COD and NH 4 + -N removal followed first order kinetics in different zones of wetland.

New insights into the source of decadal increase in chemical oxygen demand associated with dissolved organic carbon in Dianchi Lake.

PubMed

Guo, Wei; Yang, Feng; Li, Yanping; Wang, Shengrui

2017-12-15

Dissolved organic carbon (DOC) can be used an alternative index of water quality instead of chemical oxygen demand (COD) to reflect the organic pollution in water. The monitoring data of water quality in a long-term (1990-2013) from Dianchi Lake confirmed the increase trend of COD concentration in the lake since 2007. The similarities and differences in the DOC components between the lake and its sources and the contribution from allochthonous and autochthonous DOC to the total DOC in this lake were determined to elucidate the reason of COD increase based on C/N atomic ratios, stable isotope abundance of carbon and nitrogen, UV-visible spectroscopy, three-dimensional excitation-emission matrix (3DEEM) fluorescence spectroscopy. The terrigenous organic matter showed humic-like fluorescence, and the autochthonous organic matter showed tryptophan-like components. Agricultural runoff (9.5%), leaf litter (7.5%) and urban runoff (13.2%) were the main sources of DOC in the lake. Sewage tail was a major source of organic materials, 3DEEM for the indicates that sewage tail DOC composition did not change markedly over the biodegradation period, indicating that sewage tail contains a high load of DOC that is resistant to further biodegradation and subsequently accumulates in the lake. The change of land use in the catchment and the increase of sewage tail load into the lake are the key factors for the increase in COD concentration in Dianchi Lake. Thus, the lake should be protected by controlling the pollution from the urban nonpoint sources and refractory composition in point sources. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination and identification of hydrophilic and hydrophobic arsenic species in methanol extract of fresh cod liver by RP-HPLC with simultaneous ICP-MS and ESI-Q-TOF-MS detection.

PubMed

Arroyo-Abad, Uriel; Lischka, Susanne; Piechotta, Christian; Mattusch, Jürgen; Reemtsma, Thorsten

2013-12-01

The present study was focused on the determination and identification of arsenic species in methanolic extracts of cod liver. Arsenic species were fractionated and the fractions analysed by RP-HPLC-ICP-MS coupled with ESI-Q-TOF-MS. The total concentration of arsenic in the fresh cod liver was analysed by ICP-MS to be 1.53±0.02 mg As kg(-1)w.w. and the extraction recovery was ca. 100% and the column recovery >93%. Besides polar inorganic and methylated arsenic species (>70%) more hydrophobic arsenic-containing fatty acids and hydrocarbons occurred. Based on the mass spectrometric data proposals for molecular structures were elaborated for 20 of the organic As species included 10 arsenic-containing fatty acids (AsFA) and an arsenic-containing hydrocarbon (AsHC) mentioned for the first time in fresh cod liver. Arsenobetaine was found as main water-soluble arsenic compound in cod liver followed by higher molecular mass arsenic-containing fatty acids and hydrocarbons. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Anaerobic digestion for treatment of stillage from cellulosic bioethanol production.

PubMed

Tian, Zhuoli; Mohan, Gayathri Ram; Ingram, Lonnie; Pullammanappallil, Pratap

2013-09-01

Thermophilic anaerobic digestion of stillage from a cellulosic ethanol process that uses sugarcane bagasse as feedstock was investigated. A biochemical methane potential (BMP) of 200 ml CH4 at STP (g VS)(-1) was obtained. The whole stillage was separated into two fractions: a fraction retained on 0.5 mm screen called residue and a fraction passing through 0.5 mm screen called filtrate. About 70% of total methane yield of stillage was produced from the filtrate. The filtrate was anaerobically digested in a 15 L semi-continuously fed digester operated for 91 days at HRTs of 21 and 14 days and organic loading rate (OLR) of 1.85 and 2.39 g COD L(-1) d(-1). The methane yield from the stillage from the digester was about 90% of the yield from the BMP assays. The influent soluble COD (sCOD) was reduced from between 35.4 and 38.8 g COD (L(-1)) to between 7.5 and 8 g COD (L(-1)). Copyright © 2013 Elsevier Ltd. All rights reserved.

Biomethanation of poultry litter leachate in UASB reactor coupled with ammonia stripper for enhancement of overall performance.

PubMed

Gangagni Rao, A; Sasi Kanth Reddy, T; Surya Prakash, S; Vanajakshi, J; Joseph, Johny; Jetty, Annapurna; Rajashekhara Reddy, A; Sarma, P N

2008-12-01

In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26m(3)CH(4)/kg COD reduced), organic loading rate (OLR) (18.5kg COD m(-3)day(-1)) and Hydraulic residence time (HRT) (12h) compared to the UASB reactor without stripper (COD reduction: 92%; methane yield: 0.21m(3)CH(4)/kg COD reduced; OLR: 13.6kg CODm(-3)day(-1); HRT: 16h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9min are found to be optimum parameters for the operation of the stripper.

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

Improved COD Measurements for Organic Content in Flowback Water with High Chloride Concentrations.

PubMed

Cardona, Isabel; Park, Ho Il; Lin, Lian-Shin

2016-03-01

An improved method was used to determine chemical oxygen demand (COD) as a measure of organic content in water samples containing high chloride content. A contour plot of COD percent error in the Cl(-)-Cl(-):COD domain showed that COD errors increased with Cl(-):COD. Substantial errors (>10%) could occur in low Cl(-):COD regions (<300) for samples with low (<10 g/L) and high chloride concentrations (>25 g/L). Applying the method to flowback water samples resulted in COD concentrations ranging in 130 to 1060 mg/L, which were substantially lower than the previously reported values for flowback water samples from Marcellus Shale (228 to 21 900 mg/L). It is likely that overestimations of COD in the previous studies occurred as result of chloride interferences. Pretreatment with mercuric sulfate, and use of a low-strength digestion solution, and the contour plot to correct COD measurements are feasible steps to significantly improve the accuracy of COD measurements.

Composition and structure of the parasite faunas of cod, Gadus morhua L. (Teleostei: Gadidae), in the North East Atlantic.

PubMed

Perdiguero-Alonso, Diana; Montero, Francisco E; Raga, Juan Antonio; Kostadinova, Aneta

2008-07-18

Although numerous studies on parasites of the Atlantic cod, Gadus morhua L. have been conducted in the North Atlantic, comparative analyses on local cod parasite faunas are virtually lacking. The present study is based on examination of large samples of cod from six geographical areas of the North East Atlantic which yielded abundant baseline data on parasite distribution and abundance. A total of 826 fish was sampled in the Baltic, Celtic, Irish and North seas, Icelandic waters and Trondheimsfjord (Norway) in 2002 (spring and autumn) and 2003 (spring). The gills and internal organs (oesophagus, stomach, intestine, pyloric caeca, liver, heart, spleen, gall bladder and gonads) were examined for macroparasites following a standardised protocol. The taxonomic consistency of the identification was ensured thorough the entire study. We discuss some problems in parasite identification, outline the composition of the parasite faunas in cod in the six North East Atlantic regions, provide novel data on parasite prevalence and abundance and a comparative assessment of the structure of the regional parasite faunas with respect to the higher-level taxonomic groupings, host specificity and zoogeographical distribution of the parasites. Altogether 57 different parasite forms were found including seven new host records (Diclidophora merlangi, Rhipidocotyle sp., Fellodistomum sp., Steringotrema sp., Cucullanus sp., Spinitectus sp., and Chondracanthus ornatus). The predominant groups of cod parasites were trematodes (19 species) and nematodes (13 species) including larval anisakids which comprised 58.2% of the total number of individuals. Our study reveals relatively rich regional parasite faunas in cod from the North East Atlantic which are dominated by generalist parasites with Arcto-Boreal distribution. Further, it provides more detailed data on the distribution in the North East Atlantic of the majority of cod parasites which may serve as baselines for future studies on the effect of climate change. Based on the faunal comparisons, predictions can be made in relation to the structure and diversity of the parasite communities in the North East Atlantic regions studied.

Characterization of domestic graywater and graywater solids.

PubMed

Sievers, Jan Christian; Londong, Jörg

2018-03-01

The knowledge of loads and concentrations is fundamental for the design of graywater treatment units, but the data on the characteristics of graywater and in particular graywater solids are weak. As general design values regarding graywater treatment facilities are not available for Germany, the objective of this article is to elaborate the characteristics of graywater and graywater solids. This paper describes the results of six sampling campaigns carried out on graywater systems in the German cities Berlin, Lübeck and Kiel. All graywater samples were collected proportional to the flow and the graywater solids were gathered separately. The collected data include graywater volumes and characteristics regarding the organic pollution (chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD 5 )) and nutrients (total nitrogen (TN), total phosphorus (TP)). The graywater volume fluctuated depending on the location. The specific average flow was 68 litre per inhabitant per day (L/inh.d). Inhabitant-specific loads of 49.3 gCOD t /inh·d, 28 gBOD 5 /inh.d, 1 gTN t /inh.d and 0.38 gTP t /inh.d (subscript 't' = total) were found. Information about the composition of graywater solids in terms of quantity and quality is seriously lacking. Therefore, graywater solids were examined with respect to organic matter (COD) and nutrients (TN, TP). The contribution of graywater solids with particle sizes over 200 microns in relation to the total inhabitant-specific load was approximately 3-8% depending on the parameter. The qualitative and quantitative characteristics of the investigated graywater fractions may serve as a base for the estimation of design values.

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.

Simultaneous Hydrogen and Methane Production Through Multi-Phase Anaerobic Digestion of Paperboard Mill Wastewater Under Different Operating Conditions.

PubMed

Farghaly, Ahmed; Tawfik, Ahmed

2017-01-01

Multi-phase anaerobic reactor for H 2 and CH 4 production from paperboard mill wastewater was studied. The reactor was operated at hydraulic retention times (HRTs) of 12, 18, 24, and 36 h, and organic loading rates (OLRs) of 2.2, 1.5, 1.1, and 0.75 kg chemical oxygen demand (COD)/m 3  day, respectively. HRT of 12 h and OLR of 2.2 kg COD/m 3  day provided maximum hydrogen yield of 42.76 ± 14.5 ml/g COD removed and volumetric substrate uptake rate (-rS) of 16.51 ± 4.43 mg COD/L h. This corresponded to the highest soluble COD/total COD (SCOD/TCOD) ratio of 56.25 ± 3.3 % and the maximum volatile fatty acid (VFA) yield (Y VFA ) of 0.21 ± 0.03 g VFA/g COD, confirming that H 2 was mainly produced through SCOD conversion. The highest methane yield (18.78 ± 3.8 ml/g COD removed ) and -rS of 21.74 ± 1.34 mgCOD/L h were achieved at an HRT of 36 h and OLR of 0.75 kg COD/m 3  day. The maximum hydrogen production rate (HPR) and methane production rate (MPR) were achieved at carbon to nitrogen (C/N) ratio of 47.9 and 14.3, respectively. This implies the important effect of C/N ratio on the distinction between the dominant microorganism bioactivities responsible for H 2 and CH 4 production.

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.

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.

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.

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.

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.

Effect of Agitation on Acidogenesis Stage of Two-Stage Anaerobic Digestion of Palm Oil Mill Effluent (POME) into Biogas

NASA Astrophysics Data System (ADS)

Trisakti, B.; Irvan; Adipasah, H.; Taslim; Turmuzi, M.

2017-03-01

The acidogenesis stage in two-stage anaerobic digestion of palm oil mill effluent (POME) was studied in a continuous stirred tank reactor (CSTR). This research investigated the effect of agitation rate on the growth of microorganisms, the degradation of organic substances, and volatile fatty acids (VFA) production and composition. Initially, the suitable loading up was determined by varying the HRT 6.7, 5.0, and 4.0 days in a 2 L CSTR with agitation rate 50 rpm, pH 6.0 ± 0.2, at room temperature. Next, effect of agitation on the process was determined by varying agitation rate at 25, 50, 100, and 200 rpm. Analysis of total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (VSS), chemical oxygen demand (COD), and volatile fatty acids (VFA) were conducted in order to study the growth of microorganisms and their abilities in converting organic compound to produce VFA. The highest growth of microorganisms was achieved at HRT 4.0 day with microorganism concentration was 20.62 mg VSS/L and COD reduction was 15.7%. The highest production of total VFA achieved was 5,766.61 mg/L mg/L at agitation rate 200 rpm, with concentration of acetic acid, propionic acid and butyric acid were 1,889.23; 1,161.43; and 2,725.95 mg/L, respectively. While degradation VS and COD were 16.61 and 38.79%.

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

Long-term stability of thermophilic co-digestion submerged anaerobic membrane reactor encountering high organic loading rate, persistent propionate and detectable hydrogen in biogas.

PubMed

Qiao, Wei; Takayanagi, Kazuyuki; Niu, Qigui; Shofie, Mohammad; Li, Yu You

2013-12-01

The performance of thermophilic anaerobic co-digestion of coffee grounds and sludge using membrane reactor was investigated for 148 days, out of a total research duration of 263 days. The OLR was increased from 2.2 to 33.7 kg-COD/m(3)d and HRT was shortened from 70 to 7 days. A significant irreversible drop in pH confirmed the overload of reactor. Under a moderately high OLR of 23.6 kg-COD/m(3)d, and with HRT and influent total solids of 10 days and 150 g/L, respectively, the COD removal efficiency was 44.5%. Hydrogen in biogas was around 100-200 ppm, which resulted in the persistent propionate of 1.0-3.2g/L. The VFA consumed approximately 60% of the total alkalinity. NH4HCO3 was supplemented to maintain alkalinity. The stability of system relied on pH management under steady state. The 16SrDNA results showed that hydrogen-utilizing methanogens dominates the archaeal community. The propionate-oxidizing bacteria in bacterial community was insufficient. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodegradation of a Real Dye Wastewater Containing High Concentration of Total Dissolved Inorganic Salts (TDIS) in a Lab-Scale Activated Sludge Unit

NASA Astrophysics Data System (ADS)

Patel, Upendra D.; Ruparelia, Jayesh; Patel, Margi

2017-11-01

Biodegradation studies on Dye wastewater (DW) are normally conducted on simulated wastewaters or aqueous dyes solutions supported by growth medium, and often, an easy carbon source such as glucose. This rarely resembles actual DW which is characterized by the presence of complex organic compounds, and a high concentration of Total Dissolved Inorganic Salts (TDIS). Biodegradation of real Direct Dyes Wastewater (DDW), and a mixed-waste stream (MWS) consisting of equal volumes of Direct and Acid dyes wastewaters, was carried out using a lab-scale activated sludge unit. The DDW and MWS had TDIS and COD concentrations of 105 and 4.5 g/L, and 54 and 4.1 g/L, respectively. After acclimatization process of 70 days, 67% COD removal was achieved at influent TDIS and COD concentrations of 79.6 g/L and 4320 mg/L, respectively, for the DDW at HRT of 3 days and MLVSS concentration of 2000 mg/L. Although no sludge wastage was done, initially increased concentration of MLVSS ( 2400 mg/L) decreased to 1700 mg/L with increase in TDIS. Using the biomass acclimatized for DDW for treatment of MWS, consistent COD removal of 70% was achieved at HRT of 4.3 days and an MLVSS concentration of 1600 mg/L. Results suggest that significant COD removal can be achieved in real DW if biomass is gradually acclimatized to increasing TDIS concentrations.

Application of Moringa Oleifera seed extract to treat coffee fermentation wastewater.

PubMed

Garde, William K; Buchberger, Steven G; Wendell, David; Kupferle, Margaret J

2017-05-05

Wastewater generated from wet processing of coffee cherries degrades stream water quality downstream of processing mills and impacts human health. The widespread popularity of coffee as an export makes this a global problem, although the immediate impact is local. Approximately 40% of all coffee around the world is wet processed, producing wastewater rich in organic nutrients that can be hazardous to aquatic systems. Moringa Oleifera Seed Extract (MOSE) offers promise as a local and affordable "appropriate" coagulation technology for aiding in the treatment of coffee wastewater. Field research was conducted at the Kauai Coffee Company to investigate the application of MOSE to treat coffee fermentation wastewater (CFW). Coagulation tests were conducted at five pH CFW levels (3-7) and MOSE doses (0-4g/L). After settling, TSS, COD, nitrate, nitrite, total nitrogen, and pH of supernatant from each test were measured. MOSE reduced TSS, COD, nitrate, and nitrite in CFW to varying degrees dependent on pH and dose applied. TSS removal ranged from 8% to 54%. Insoluble COD removal ranged from 26% to 100% and total COD removal ranged from 1% to 25%. Nitrate and nitrite reduction ranged from 20% to 100%. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Evaluation of organic matter concentration in winery wastewater: a case study from Australia.

PubMed

Quayle, Wendy C; Fattore, Alison; Zandona, Roy; Christen, Evan W; Arienzo, Michele

2009-01-01

The 5-day biological oxygen demand (BOD(5)) remains a key indicator for proof of compliance with environmental regulators in the monitoring and management of winery effluent. Inter-conversion factors from alternative tests that are more rapid, accurate and simpler to perform have been determined that allow prediction of BOD(5) in winery wastewaters, generally, and at different stages of production and treatment. Mean values obtained from this dataset offer rule of thumb inter-conversion factors: BOD(5) = 0.7 Chemical Oxygen Demand (COD), BOD(5) = 2.3 Total Organic Carbon (TOC) and BOD(5) = 2.7 Dissolved Organic Carbon (DOC). Specific predictive linear relationships are also provided. Out of the relationships between BOD(5) vs COD, TOC and DOC, in winery wastewater, irrespective of vintage or non-vintage production periods and stage of treatment, TOC offered the most reliable prediction of BOD(5). Ethanol, glucose and fructose were evaluated in untreated wastewater as predictors of BOD(5) due to their high specificity in winery effluent. A significant relationship was determined between BOD(5) and (ethanol + glucose + fructose; R(2) = 0.64, n = 19; p<0.05), but relationships between BOD(5) and ethanol and BOD(5) vs (glucose + fructose) were weak (R(2) = 0.45 and 0.34; n = 19; p<0.05 respectively,). There was a very strong linear correlation (y = 0.9767x + 52.8; R(2) = 0.97; n = 23; p<0.05) in COD data in winery effluents when using a commercially available mercury free test kit compared with using a traditional COD test kit that contained mercury. This suggests that mercury free COD test kits could be used by the wine industry for organic pollution assessment with associated reductions to user and environmental risk, as well as reducing the costs of kit waste disposal.

Cape Cod Transit Task Force : Five-Year Public Transportation Plan

DOT National Transportation Integrated Search

2002-06-30

The U.S. Department of Transportation's Volpe National Transportation Systems : Center has been working in cooperation with the Cape Cod Regional Transit : Authority, the Cape Cod Commission, and other organizations participating on : the Cape Cod Tr...

Assessment of anthropogenic inputs in the surface waters of the southern coastal area of Sfax during spring (Tunisia, Southern Mediterranean Sea).

PubMed

Drira, Zaher; Kmiha-Megdiche, Salma; Sahnoun, Houda; Hammami, Ahmed; Allouche, Noureddine; Tedetti, Marc; Ayadi, Habib

2016-03-15

The coastal marine area of Sfax (Tunisia), which is well-known for its high productivity and fisheries, is also subjected to anthropogenic inputs from diverse industrial, urban and agriculture activities. We investigated the spatial distribution of physical, chemical and biogeochemical parameters in the surface waters of the southern coastal area of Sfax. Pertinent tracers of anthropogenic inputs were identified. Twenty stations were sampled during March 2013 in the vicinity of the coastal areas reserved for waste discharge. Phosphogypsum wastes dumped close to the beaches were the main source of PO4(3-), Cl(-) and SO4(2-) in seawater. The high content in total polyphenolic compounds was due to the olive oil treatment waste water released from margins. These inorganic and organic inputs in the surface waters were associated with elevated COD. The BOD5/COD (<0.5) and COD/BOD5 (>3) ratios highlighted a chemical pollution with organic load of a low biodegradability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development and optimization of dark Fenton oxidation for the treatment of textile wastewaters with high organic load.

PubMed

Papadopoulos, A E; Fatta, D; Loizidou, M

2007-07-31

The examination of the effectiveness of the chemical oxidation using Fenton's reagent (H(2)O(2)/Fe(2+)) for the reduction of the organic content of wastewater generated from a textile industry has been studied. The experimental results indicate that the oxidation process leads to a reduction in the chemical oxygen demand (COD) concentration up to 45%. Moreover, the reduction is reasonably fast at the first stages of the process, since the COD concentration is decreased up to 45% within four hours and further treatment time does not add up to the overall decrease in the COD concentration (48% reduction within six hours). The maximum color removal achieved was 71.5%. In addition, the alterations observed in the organic matter during the development of the process, as indicated by the ratios of COD/TOC and BOD/COD and the oxidation state, show that a great part of the organic substances, which are not completely mineralized, are subjected to structural changes to intermediate organic by-products.

Specific inhibition of Photobacterium phosphoreum extends the shelf life of modified-atmosphere-packed cod fillets.

PubMed

Dalgaard, P; Garcia Munoz, L; Mejlholm, O

1998-09-01

Inhibition of the specific spoilage organism, Photobacterium phosphoreum, was studied in model substrates and in modified-atmosphere-packed cod fillets. The objective was to determine how inhibition of this organism influenced spoilage. The spoilage reactions limiting shelf life were studied rather than the development of a new product. In naturally contaminated modified-atmosphere-packed cod fillets, 500 ppm Na2CaEDTA reduced the growth rate of P. phosphoreum by 40% and shelf life was increased proportionally by 40%, from 15 to 17 days to 21 to 23 days at 0 degree C. In aerobically stored cod fillets other microorganisms were responsible for spoilage and Na2CaEDTA had no effect on shelf life. The extension of the shelf life of modified-atmosphere-packed cod therefore was a result of the reduced growth of P. phosphoreum and no other microbial or nonmicrobial spoilage reactions limited shelf life. These results confirmed P. phosphoreum as the specific spoilage organism in modified-atmosphere-packed cod and showed the organism to have an extensive spoilage domain. Consequently, any preservation procedure able to reduce growth of P. phosphoreum is likely to extend shelf life of packed cod. However, the effect of different inhibitory compounds in model systems as well as results from packed cod indicated the need to include product studies in the screening of antimicrobials and in the development of preservation procedures.

Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences.

PubMed

Zuo, Shaozhi; Huwer, Bastian; Bahlool, Qusay; Al-Jubury, Azmi; Daugbjerg Christensen, Nanna; Korbut, Rozalia; Kania, Per; Buchmann, Kurt

2016-06-15

A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6% of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod (>38 cm) compared to smaller cod (<30 cm) recently recorded in the Baltic cod population.

Biotreatment of Petrochemical Wastewater: A Case Study from Northern Tunisia.

PubMed

Jemli, Meryem; Zaghden, Hatem; Rezgi, Fatma; Kchaou, Sonia; Aloui, Fathi; Sayadi, Sami

2017-03-01

  A full-scale study has been conducted to assess the bioaugmentation efficiency of trickling filter process to treat petrochemical wastewater from a lubricant industry recycling waste oils. During 45 weeks, the organic loading rate (OLR) in the trickling filter was increased stepwise from 0.9 to 4 kg of chemical oxygen demand (COD)/(m3·day) at the end of the upgrading period as the flow rate (FR) reached the value of 30 m3/day. The removal, obtained in terms of percentage, for COD ranged from 60 to 84.5 and greater than 98 for total n-alkane (TNA), while those of total kjeldahl nitrogen (TKN) and total phosphor (TP) were about 32 and 55, respectively. The analytical profile index (API) of trickling biofilm has confirmed that 5 strains are closely related to Acinobacter junii, Stenotrophomonas maltophilia, Vibrio vulnificus, Vibrio metschnikovi, Pseudomona slulzeri and Trichosporon spp2.

77 FR 19944 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-03

... will constrain catch to the recreational sub-ACL; and reduce overfishing occurring on GOM cod in...). This interim rule implements a total GOM cod total annual catch limit (ACL) of 6,700 mt and divides... implementing interim measures: Setting a total GOM cod ACL in a 6,700 to 7,500 mt range; Modifying the...

Determining TOC in Waters

ERIC Educational Resources Information Center

Kehoe, Thomas J.

1977-01-01

The instrumental method for detecting total organic carbon (TOC) in water samples is detailed. The method's limitations are discussed and certain precautions that must be taken are emphasized. The subject of TOC versus COD and BOD is investigated and TOC is determined to be a valid indication of biological demand. (BT)

[Pollution load and the first flush effect of BOD5 and COD in urban runoff of Wenzhou City].

PubMed

Wang, Jun; Bi, Chun-juan; Chen, Zhen-lou; Zhou, Dong

2013-05-01

Four typical rainfalls were monitored in two different research areas of Wenzhou Municipality. Concentrations of BOD5 and COD in six different urban runoffs were measured. In addition the event mean concentration (EMC), M (V) curve and BOD5/COD of pollutant were calculated. The results showed that concentrations of BOD5 and COD in different urban runoffs of Wenzhou ranged from ND to 69.21 mg x L(-1) and ND to 636 mg x L(-1). Concentrations of BOD5 and COD in different urban runoffs were decreasing over time, so it is greatly significant to manage the initial runoff for reducing organic pollution. Judged by EMC of BOD5 and COD in these five rainfalls, concentrations of pollutant in some urban runoffs were out of the integrated wastewater discharge standard. If these runoffs flowed into river, it would cause environmental pressure to the next level receiving water bodies. According to the M (V) curve, the first flush effect of COD in most urban runoffs was common; while the first flush effect of BOD5 was same as that of COD. The result also showed that organic pollution was serious at the beginning of runoff. The underlying surface type could affect the concentration of BOD5 and COD in urban runoff. While the results of BOD5/COD also suggested that biodegradation was considered as one of the effective ways to decrease the pollution load of organics in urban runoff, and the best management plans (BMPs) should be selected for various urban runoff types for the treatment of organic pollution.

Immobilizing of catalyst using Bayah's natural zeolite to reduce the chemical oxygen demand (COD) and total organic carbon (TOC)

NASA Astrophysics Data System (ADS)

Jayanudin, Kustiningsih, Indar; Sari, Denni Kartika

2017-05-01

Indonesia is rich of natural minerals, many of which had not been widely used. One potential natural mineral is zeolite from Bayah Banten that can be used to support catalyst in the process of waste degradation. The purpose of this research is to characterize the Bayah's zeolite and to figure out the effectiveness of the zeolite as supporting agent to the Fe catalyst in the process of phenol degradation, with the main purposes are to reduce the Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC). This research consists of three steps, activation of natural zeolite using 1M, 2M, and 3M NaOH solution, impregnation process with 0.025M, 0.05 M and 0.075M Fe(NO3)3.9H2O solution, and calcination at 500°C. Bayah's natural zeolite was characterize using Brauner-Emmet-Teller (BET) for its pore area, X-ray Fluorescence (XRF) for analyzing zeolite's component before and after activation process and after impregnation process, and Scanning Electron Microscope (SEM) for analyzing zeolite's morphology. The result showed that the highest pore area was 9Å, Fe metal from Fe(NO3)3.9H2O 0,075 M solution remained in zeolite pore was 7,73%, the reduction of COD and TOC was yielded at H2O2: phenol ratio of 1 : 6.

Estimating the Concentration and Biodegradability of Organic Matter in 22 Wastewater Treatment Plants Using Fluorescence Excitation Emission Matrices and Parallel Factor Analysis

PubMed Central

Yang, Liyang; Shin, Hyun-Sang; Hur, Jin

2014-01-01

This study aimed at monitoring the changes of fluorescent components in wastewater samples from 22 Korean biological wastewater treatment plants and exploring their prediction capabilities for total organic carbon (TOC), dissolved organic carbon (DOC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), and the biodegradability of the wastewater using an optical sensing technique based on fluorescence excitation emission matrices and parallel factor analysis (EEM-PARAFAC). Three fluorescent components were identified from the samples by using EEM-PARAFAC, including protein-like (C1), fulvic-like (C2) and humic-like (C3) components. C1 showed the highest removal efficiencies for all the treatment types investigated here (69% ± 26%–81% ± 8%), followed by C2 (37% ± 27%–65% ± 35%), while humic-like component (i.e., C3) tended to be accumulated during the biological treatment processes. The percentage of C1 in total fluorescence (%C1) decreased from 54% ± 8% in the influents to 28% ± 8% in the effluents, while those of C2 and C3 (%C2 and %C3) increased from 43% ± 6% to 62% ± 9% and from 3% ± 7% to 10% ± 8%, respectively. The concentrations of TOC, DOC, BOD, and COD were the most correlated with the fluorescence intensity (Fmax) of C1 (r = 0.790–0.817), as compared with the other two fluorescent components. The prediction capability of C1 for TOC, BOD, and COD were improved by using multiple regression based on Fmax of C1 and suspended solids (SS) (r = 0.856–0.865), both of which can be easily monitored in situ. The biodegradability of organic matter in BOD/COD were significantly correlated with each PARAFAC component and their combinations (r = −0.598–0.613, p < 0.001), with the highest correlation coefficient shown for %C1. The estimation capability was further enhanced by using multiple regressions based on %C1, %C2 and C3/C2 (r = −0.691). PMID:24448170

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.

Comparison of Fenton and Fenton-like oxidation for the treatment of cosmetic wastewater.

PubMed

Bautista, P; Casas, J A; Zazo, J A; Rodriguez, J J; Mohedano, A F

2014-01-01

The treatment of cosmetic wastewaters by Fenton (Fe²⁺/H₂O₂) and Fenton-like (Fe³⁺/H₂O₂) oxidation has been studied. From batch and continuous experiments it has been proved that both versions of the Fenton process lead to quite similar results in terms of chemical oxygen demand (COD) and total organic carbon reduction although the COD shows a slightly higher rate in the early stages of reaction. COD reductions of around 55% after 2 h reaction time and 75-80% with 4 h residence time were reached in batch and continuous experiments, respectively, conducted at pH around 3, ambient temperature (20 °C), with 200 mg/L of Fe dose and an initial H₂O₂/COD weight ratio corresponding to the theoretical stoichiometric value. Achieving the locally allowable limit of COD for industrial wastewater discharge into the municipal sewer system takes no more than 30 min reaction time under those conditions by both Fenton systems. However, the Fenton-like process, where iron is fed as Fe(3+), would be preferable for industrial applications since the ferric sludge resulting upon final neutralization of the effluent can be recycled to the process. A second-order kinetic equation with respect to COD fitted fairly well the experimental results at different temperatures, thus providing a simple practical tool for design purposes.

Anaerobic treatment of blended sugar industry and ethanol distillery wastewater through biphasic high rate reactor.

PubMed

Fito, Jemal; Tefera, Nurelegne; Kloos, Helmut; Van Hulle, Stijn W H

2018-06-07

This study aimed to investigate the physicochemical properties of sugar industry and ethanol distillery wastewater and the treatment of the blended wastewater through a two-stage anaerobic reactor. For this treatment, different initial chemical oxygen demand (COD) concentrations (5-20 g/L) and hydraulic retention times (HRTs) (2-10 days) were applied. The sugar industry effluent characteristics obtained in terms of organic matter (mg/L) were as follows: 5 days biochemical oxygen demand (BOD 5 ): 654.5-1,968; COD: 1,100-2,148.9; total solids (TS): 2,467-4,012 mg/L; and pH: 6.93-8.43. The ethanol distillery spent wash strengths obtained were: BOD 5 : 27,600-42,921 mg/L; COD: 126,000-167,534 mg/L; TS: 140,160-170,000 mg/L; and pH: 3.9-4.2. Maximum COD removal of 65% was obtained at optimum condition (initial COD concentration of 10 g/L and HRT of 10 days), and maximum color removal of 79% was recorded under similar treatment conditions. Hence, the performance of the two-stage anaerobic reactor for simultaneous removal of COD and color from high-strength blended wastewater is promising for scaling up in order to mitigate environmental problems of untreated effluent discharge.

Biodegradability of organic matter associated with sewer sediments during first flush.

PubMed

Sakrabani, Ruben; Vollertsen, Jes; Ashley, Richard M; Hvitved-Jacobsen, Thorkild

2009-04-01

The high pollution load in wastewater at the beginning of a rain event is commonly known to originate from the erosion of sewer sediments due to the increased flow rate under storm weather conditions. It is essential to characterize the biodegradability of organic matter during a storm event in order to quantify the effect it can have further downstream to the receiving water via discharges from Combined Sewer Overflow (CSO). The approach is to characterize the pollutograph during first flush. The pollutograph shows the variation in COD and TSS during a first flush event. These parameters measure the quantity of organic matter present. However these parameters do not indicate detailed information on the biodegradability of the organic matter. Such detailed knowledge can be obtained by dividing the total COD into fractions with different microbial properties. To do so oxygen uptake rate (OUR) measurements on batches of wastewater have shown itself to be a versatile technique. Together with a conceptual understanding of the microbial transformation taking place, OUR measurements lead to the desired fractionation of the COD. OUR results indicated that the highest biodegradability is associated with the initial part of a storm event. The information on physical and biological processes in the sewer can be used to better manage sediment in sewers which can otherwise result in depletion of dissolved oxygen in receiving waters via discharges from CSOs.

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

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.

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.

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.

Performance assessment of two-stage anaerobic digestion of kitchen wastes.

PubMed

Bo, Zhang; Pin-Jing, He

2014-01-01

This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition

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

Liu Zhanguang; Zhou Xuefei; Zhang Yalei, E-mail: zhangyalei2003@163.com

Highlights: Black-Right-Pointing-Pointer Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure. Black-Right-Pointing-Pointer The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was key controlling factor. Black-Right-Pointing-Pointer The threshold of the SCOD/TAN ratio was 2.4 at an influent pH of 8.5-9. - Abstract: The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700 m{sup 3} chicken-manure continuous stirred tank reactor (CSTR). A 12.3 L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35 {+-} 1 Degree-Sign C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5more » kg-COD/m{sup 3} d over a hydraulic retention time of 1.5 d, a maximum volumetric biogas production rate of 1.2 m{sup 3}/m{sup 3} d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250 mg/L) at an influent pH of 8.5-9.« less

Effects of Psychrophilic Storage on Manures as Substrate for Anaerobic Digestion

PubMed Central

Bergland, Wenche; Dinamarca, Carlos

2014-01-01

The idea that storage can enhance manure quality as substrate for anaerobic digestion (AD) to recover more methane is evaluated by studying storage time and temperature effects on manure composition. Volatile fatty acids (VFA) and total dissolved organics (CODs) were measured in full scale pig manure storage for a year and in multiple flasks at fixed temperatures, mainly relevant for colder climates. The CODs generation, influenced by the source of the pig manure, was highest initially (0.3 g COD L−1d−1) gradually dropping for 3 months towards a level of COD loss by methane production at 15°C. Methane emission was low (<0.01 g COD L−1d−1) after a brief initial peak. Significant CODs generation was obtained during the warmer season (T > 10°C) in the full scale storage and almost no generation at lower temperatures (4–6°C). CODs consisted mainly of VFA, especially acetate. All VFAs were present at almost constant ratios. The naturally separated manure middle layer without sediment and coarser particles is suitable for sludge bed AD and improved further during an optimal storage time of 1–3 month(s). This implies that high rate AD can be integrated with regular manure slurry handling systems to obtain efficient biogas generation. PMID:25165712

Natural light-micro aerobic condition for PSB wastewater treatment: a flexible, simple, and effective resource recovery wastewater treatment process.

PubMed

Lu, Haifeng; Han, Ting; Zhang, Guangming; Ma, Shanshan; Zhang, Yuanhui; Li, Baoming; Cao, Wei

2018-01-01

Photosynthetic bacteria (PSB) have two sets of metabolic pathways. They can degrade pollutants through light metabolic under light-anaerobic or oxygen metabolic pathways under dark-aerobic conditions. Both metabolisms function under natural light-microaerobic condition, which demands less energy input. This work investigated the characteristics of PSB wastewater treatment process under that condition. Results showed that PSB had very strong adaptability to chemical oxygen demand (COD) concentration; with F/M of 5.2-248.5 mg-COD/mg-biomass, the biomass increased three times and COD removal reached above 91.5%. PSB had both advantages of oxygen metabolism in COD removal and light metabolism in resource recovery under natural light-microaerobic condition. For pollutants' degradation, COD, total organic carbon, nitrogen, and phosphorus removal reached 96.2%, 91.0%, 70.5%, and 92.7%, respectively. For resource recovery, 74.2% of C in wastewater was transformed into biomass. Especially, coexistence of light and oxygen promote N recovery ratio to 70.9%, higher than with the other two conditions. Further, 93.7% of N-removed was synthesized into biomass. Finally, CO 2 emission reduced by 62.6% compared with the traditional process. PSB wastewater treatment under this condition is energy-saving, highly effective, and environment friendly, and can achieve pollution control and resource recovery.

Anaerobic treatment of antibiotic production wastewater pretreated with enhanced hydrolysis: Simultaneous reduction of COD and ARGs.

PubMed

Yi, Qizhen; Zhang, Yu; Gao, Yingxin; Tian, Zhe; Yang, Min

2017-03-01

The presence of high concentration antibiotics in wastewater can disturb the stability of biological wastewater treatment systems and promote generation of antibiotic resistance genes (ARGs) during the treatment. To solve this problem, a pilot system consisting of enhanced hydrolysis pretreatment and an up-flow anaerobic sludge bed (UASB) reactor in succession was constructed for treating oxytetracycline production wastewater, and the performance was evaluated in a pharmaceutical factory in comparison with a full-scale anaerobic system operated in parallel. After enhanced hydrolysis under conditions of pH 7 and 85 °C for 6 h, oxytetracycline production wastewater with an influent chemical oxygen demand (COD) of 11,086 ± 602 mg L -1 was directly introduced into the pilot UASB reactor. With the effective removal of oxytetracycline and its antibacterial potency (from 874 mg L -1 to less than 0.61 mg L -1 and from 900 mg L -1 to less than 0.84 mg L -1 , respectively) by the enhanced hydrolysis pretreatment, an average COD removal rate of 83.2%, 78.5% and 68.9% was achieved at an organic loading rate of 3.3, 4.8 and 5.9 kg COD m -3  d -1 , respectively. At the same time, the relative abundances of the total tetracycline (tet) genes and a mobile element (Class 1 integron (intI1)) in anaerobic sludge on day 96 were one order of magnitude lower than those in inoculated sludge on day 0 (P < 0.01). The reduction of ARGs was further demonstrated by metagenomic sequencing. By comparison, the full-scale anaerobic system treating oxytetracycline production wastewater with an influent COD of 3720 ± 128 mg L -1 after dilution exhibited a COD removal of 51 ± 4% at an organic loading rate (OLR) 1.2 ± 0.2 kg m -3  d -1 , and a total tet gene abundance in sludge was five times higher than the pilot-scale system (P < 0.01). The above result demonstrated that enhanced hydrolysis as a pretreatment method could enable efficient anaerobic treatment of oxytetracycline production wastewater containing high concentrations of oxytetracycline with significantly lower generation of ARGs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance, carotenoids yield and microbial population dynamics in a photobioreactor system treating acidic wastewater: Effect of hydraulic retention time (HRT) and organic loading rate (OLR).

PubMed

Liu, Shuli; Zhang, Guangming; Zhang, Jie; Li, Xiangkun; Li, Jianzheng

2016-01-01

Effects of hydraulic retention time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB (Rhodopseudomonas palustris)-chemoheterotrophic bacteria to treat volatile fatty acid wastewater. Pollutants removal, biomass production and carotenoids yield in different phases were investigated in together with functional microbial population dynamics. The results indicated that properly decreasing HRT and increasing OLR improved the nutrient removal performance as well as the biomass and carotenoids productions. 85.7% COD, 89.9% TN and 91.8% TP removals were achieved under the optimal HRT of 48h and OLR of 2.51g/L/d. Meanwhile, the highest biomass production and carotenoids yield were 2719.3mg/L and 3.91mg/g-biomass respectively. In addition, HRT and OLR have obvious impacts on PNSB and total bacteria dynamics. Statistical analyses indicated that the COD removal exhibited a positive relationship with OLR, biomass and carotenoids production. PNSB/total bacteria ratio had a positive correlation with the carotenoids yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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.

Effect of temperature on the treatment of domestic wastewater with a staged anaerobic fluidized membrane bioreactor.

PubMed

Yoo, R H; Kim, J H; McCarty, P L; Bae, J H

2014-01-01

A laboratory staged anaerobic fluidized membrane bioreactor (SAF-MBR) system was applied to the treatment of primary clarifier effluent from a domestic wastewater treatment plant with temperature decreasing from 25 to 10 °C. At all temperatures and with a total hydraulic retention time of 2.3 h, overall chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) removals were 89% and 94% or higher, with permeate COD and BOD5 of 30 and 7 mg/L or lower, respectively. No noticeable negative effects of low temperature on organic removal were found, although a slight increase to 3 mg/L in volatile fatty acids concentrations in the effluent was observed. Biosolids production was 0.01-0.03 kg volatile suspended solids/kg COD, which is far less than that with aerobic processes. Although the rate of trans-membrane pressure at the membrane flux of 9 L/m(2)/h increased as temperature decreased, the SAF-MBR was operated for longer than 200 d before chemical cleaning was needed. Electrical energy potential from combustion of the total methane production (gaseous and dissolved) was more than that required for system operation.

Treatment of laboratory wastewater in a tropical constructed wetland comparing surface and subsurface flow.

PubMed

Meutia, A A

2001-01-01

Wastewater treatment by constructed wetland is an appropriate technology for tropical developing countries like Indonesia because it is inexpensive, easily maintained, and has environmentally friendly and sustainable characteristics. The aim of the research is to examine the capability of constructed wetlands for treating laboratory wastewater at our Center, to investigate the suitable flow for treatment, namely vertical subsurface or horizontal surface flow, and to study the effect of the seasons. The constructed wetland is composed of three chambered unplanted sedimentation tanks followed by the first and second beds, containing gravel and sand, planted with Typha sp.; the third bed planted with floating plant Lemna sp.; and a clarifier with two chambers. The results showed that the subsurface flow in the dry season removed 95% organic carbon (COD) and total phosphorus (T-P) respectively, and 82% total nitrogen (T-N). In the transition period from the dry season to the rainy season, COD removal efficiency decreased to 73%, T-N increased to 89%, and T-P was almost the same as that in the dry season. In the rainy season COD and T-N removal efficiencies increased again to 95% respectively, while T-P remained unchanged. In the dry season, COD and T-P concentrations in the surface flow showed that the removal efficiencies were a bit lower than those in the subsurface flow. Moreover, T-N removal efficiency was only half as much as that in the subsurface flow. However, in the transition period, COD removal efficiency decreased to 29%, while T-N increased to 74% and T-P was still constant, around 93%. In the rainy season, COD and T-N removal efficiencies increased again to almost 95%. On the other hand, T-P decreased to 76%. The results show that the constructed wetland is capable of treating the laboratory wastewater. The subsurface flow is more suitable for treatment than the surface flow, and the seasonal changes have effects on the removal efficiency.

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.

The effect of landfill age on municipal leachate composition.

PubMed

Kulikowska, Dorota; Klimiuk, Ewa

2008-09-01

The influence of municipal landfill age on temporal changes in municipal leachate quality on the basis of elaboration of 4 years monitoring of leachate from landfill in Wysieka near Bartoszyce (Poland) is presented in this study. In leachate, concentrations of organic compounds (COD, BOD(5)), nutrients (nitrogen, phosphorus), mineral compounds, heavy metals and BTEX were investigated. It was shown that the principal pollutants in leachate were organics and ammonia - as landfill age increased, organics concentration (COD) in leachate decreased from 1,800 mg COD/l in the second year of landfill exploitation to 610 mg COD/l in the sixth year of exploitation and increase of ammonia nitrogen concentration from 98 mg N(NH)/l to 364 mg N(NH4) /l was observed. Fluctuation of other indexes (phosphorus, chlorides, calcium, magnesium, sulfate, dissolved solids, heavy metals, BTEX) depended rather on season of the year (seasonal variations) than landfill age. Moreover, the obtained data indicate that despite of short landfill's lifetime some parameters e.g. high pH (on average 7.84), low COD concentration (<2,000 mg COD/l), low BOD(5)/COD ratio (<0.4) and low heavy metal concentration, indicated that the landfill was characterized by methanogenic conditions already at the beginning of the monitoring period.

Microwave Thermal Hydrolysis Of Sewage Sludge As A Pretreatment Stage For Anaerobic Digestion

NASA Astrophysics Data System (ADS)

Qiao, W.; Wang, W.; Xun, R.

2008-02-01

This article focuses on the effects of microwave thermal hydrolysis on sewage sludge anaerobic digestion. Volatile suspended solid (VSS) and COD solubilization of treated sludge were investigated. It was found that the microwave hydrolysis provided a rapid and efficient process to release organics from sludge. The increase of organic dissolution ratio was not obvious when holding time was over 5 min. The effect of the VSS solubilization was mainly dependent on temperature. The highest value of VSS dissolving ratio, 36.4%, was obtained at 170 °C for 30 min. COD dissolving ratio was about 25% at 170 °C. BMP test of excess sludge and mixture of primary and excess sludge proved the increase of methane production. Total biogas production of microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days digestion. For excess sludge, biogas production was 11.1% to 25.9% higher than untreated sludge.

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.

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.

Treatment of winery wastewater by anodic oxidation using BDD electrode.

PubMed

Candia-Onfray, Christian; Espinoza, Nicole; Sabino da Silva, Evanimek B; Toledo-Neira, Carla; Espinoza, L Carolina; Santander, Rocío; García, Verónica; Salazar, Ricardo

2018-05-04

The effective removal of organics from winery wastewater was obtained in real residual effluents from the wine industry using anodic oxidation (AO). The effluent had an initial organic load of [COD] 0 of 3490 mg L -1 equal to [TOC] 0 of 1320 mg L -1 . In addition, more than 40 organic compounds were identified by means of GC-MS. Different density currents as well as the addition of electrolytes were tested during electrolysis. The results show the decay of [COD] t by 63.6% when no support electrolyte was added, whereas almost total mineralization and disinfection was reached after adding of 50 mM of sodium sulfate and sodium chloride and applying higher density currents. The presence of sulfate and chloride in large concentration favors the production of oxidants such as hydroxyl radicals and active chlorine species that react with organics in solution. Moreover, the addition of a supporting electrolyte to industrial wastewater increases conductivity, reduces cell potential and therefore, decreases the energy consumption of the AO process. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

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

Determination of COD based on Photoelectrocatalysis of FeTiO3.TiO2/Ti Electrode

NASA Astrophysics Data System (ADS)

Wibowo, D.; Ruslan; Maulidiyah; Nurdin, M.

2017-11-01

Iron infrastructure technology of (Fe)-doped TiO2 nanotubes arrays (NTAs) was prepared for COD photoelectrocatalysis sensor. Fe-TiO2 NTAs was prepared using sol-gel method and coated with TiO2/Ti electrode by immersion technique. The optimization of COD photoelectrocatalytic sensor against Rhodamine B, Methyl Orange, and Methylene Blue organic dyes using photoelectrochemical system in a batch reactor. The high ordered FeTiO3.TiO2/Ti NTAs to determine COD value showed the high photocurrent response linearity and sensitivity to MO organic dye from the concentration of 5 ppm to 75 ppm with an average RSD value of 3.35. The development in this research is to utilize ilmenite mineral as model applied to COD sensor.

Satellite monitoring temperature conditions spawning area of the Northeast Arctic cod in the Norwegian Sea and assessment its abundance

NASA Astrophysics Data System (ADS)

Vanyushin, George; Bulatova, Tatiana; Klochkov, Dmitriy; Troshkov, Anatoliy; Kruzhalov, Michail

2013-04-01

In this study, the attempt to consider the relationship between sea surface anomalies of temperature (SST anomalies °C) in spawning area of the Norwegian Arctic cod off the Lofoten islands in coastal zone of the Norwegian Sea and modern cod total stock biomass including forecasting assessment of future cod generation success. Continuous long-term database of the sea surface temperature (SST) was created on the NOAA satellites data. Mean monthly SST and SST anomalies are computed for the selected area on the basis of the weekly SST maps for the period of 1998-2012. These maps were plotted with the satellite SST data, as well as information of vessels, byoies and coastal stations. All data were classified by spawning seasons (March-April) and years. The results indicate that poor and low middle generations of cod (2001, 2006, 2007) occurred in years with negative or extremely high positive anomalies in the spawning area. The SST anomalies in years which were close to normal or some more normal significances provide conditions for appearance strong or very strong generations of cod (1998, 2000, 2002, 2004, 2005, 2006, 2008, 2009). Temperature conditions in concrete years influence on different indexes of cod directly. So, the mean temperature in spawning seasons in years 1999-2005 was ≈5,0°C and SST anomaly - +0,35°C, by the way average year significances indexes of cod were: total stock biomass - 1425,0 th.t., total spawning biomass - 460,0 th.t., recruitment (age 3+) - 535,0 mln. units and landings - 530,0 th.t. In spawning seasons 2006-2012 years the average data were following: mean SST ≈6,0°C, SST anomaly - +1,29°C, total stock biomass - 2185,0 th.t., total spawning biomass - 1211,0 th.t., recruitment (age 3+) - 821,0 mln. units and landings - 600,0 th.t. The SST and SST anomalies (the NOAA satellite data) characterize increase of decrease in input of warm Atlantic waters which form numerous eddies along the flows of the main warm currents thus creating favorable conditions for development of the cod larvae and fry and provide them with food stock, finally, direct influence on forming total stock biomass of cod and helping its population forecast. Key words: satellite monitoring of SST, Northeast Arctic cod, spawning area, maps of SST, prognosis.

[Spatial distribution of COD and the correlations with other parameters in the northern region of Lake Taihu].

PubMed

Zhang, Yun-lin; Yang, Long-yuan; Qin, Bo-qiang; Gao, Guang; Luo, Lian-cong; Zhu, Guang-wei; Liu, Ming-liang

2008-06-01

Spatial variation of chemical oxygen demand (COD) concentration was documented and significant correlations between COD concentration and chromophoric dissolved organic matter (CDOM) absorption, fluorescence, DOC concentration were found based on a cruise sampling in the northern region of Lake Taihu in summer including 42 samplings. The possible source of COD was also discussed using every two cruise samplings in summer and winter, respectively. The COD concentration ranged from 3.77 to 7.96 mg x L(-1) with a mean value of (5.90 +/- 1.54) mg x L(-1). The mean COD concentrations in Meiliang Bay and the central lake basin were (6.93 +/- 0.89) mg x L(-1) and (4.21 +/- 0.49) mg x L(-1) respectively. A significant spatial difference was found between Meiliang Bay and the central lake basin in COD concentration, CDOM absorption coefficient, fluorescence, DOC and phytoplankton pigment concentrations, decreasing from the river mouth to inner bay, outer bay and the central lake basin. Significant correlations between COD concentration and CDOM absorption, fluorescence, DOC concentration, suggested that COD concentration could be estimated and organic pollution could be assessed using CDOM absorption retrieved from remote sensing images. Significant and positive correlation was found between COD concentration and chlorophyll a concentration in summer. However, the correlation was weak or no correlation was found in winter. Furthermore, a significant higher COD concentration was found in summer than in winter (p < 0.001). Our results indicated that degradation of phytoplankton blooms was the main source of COD in summer, except for river terrestrial input.

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.

Evaluation of leachate dissolved organic nitrogen discharge effect on wastewater effluent quality.

PubMed

Bolyard, Stephanie C; Reinhart, Debra R

2017-07-01

Nitrogen is limited more and more frequently in wastewater treatment plant (WWTP) effluents because of the concern of causing eutrophication in discharge waters. Twelve leachates from eight landfills in Florida and California were characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was approximately 1146mg/L and 40mg/L, respectively. Solid-phase extraction was used to fractionate the DON based on hydrophobic (recalcitrant fraction) and hydrophilic (bioavailable fraction) chemical properties. The average leachate concentrations of bioavailable (bDON) and recalcitrant (rDON) DON were 16.5mg/L and 18.4mg/L, respectively. The rDON fraction was positively correlated, but with a low R 2 , with total leachate apparent color dissolved UV 254 , chemical oxygen demand (COD), and humic acid (R 2 equals 0.38, 0.49, and 0.40, respectively). The hydrophobic fraction of DON (rDON) was highly colored. This fraction was also associated with over 60% of the total leachate COD. Multiple leachate and wastewater co-treatment simulations were carried out to assess the effects of leachate on total nitrogen wastewater effluent quality using removals for four WWTPs under different scenarios. The calculated pass through of DON suggests that leachate could contribute to significant amounts of nitrogen discharged to aquatic systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of a stratified sand filter in removal of chemical oxygen demand, total suspended solids and ammonia nitrogen from high-strength wastewaters.

PubMed

Healy, M G; Rodgers, M; Mulqueen, J

2007-06-01

A stratified sand filter column, operated in recirculation mode and treating synthetic effluent resembling high-strength dairy wastewaters was studied over a 342-d duration. The aim of this paper was to examine the organic, total suspended solids (TSS) and nutrient removal rates of the sand filter, operated in recirculation mode, under incrementally increasing hydraulic and organic loading rates and to propose a field filter-sizing criterion. Best performance was obtained at a system hydraulic loading rate of 10 L m(-2) d(-1); a higher system hydraulic loading rate (of 13.4 L m(-2) d(-1)) caused surface ponding. The system hydraulic loading rate of 10 L m(-2) d(-1) gave a filter chemical oxygen demand (COD), TSS, and total kjeldahl nitrogen (TKN) loading rate of 14, 3.7, and 2.1 g m(-2) d(-1), respectively, and produced consistent COD and TSS removals of greater than 99%, and an effluent NO(3)-N concentration of 42 mg L(-1) (accounting for an 86% reduction in total nitrogen (Tot-N)). As the proportional surface area requirement for the sand filter described in this study is less than the recommended surface area requirement of a free-water surface (FWS) wetland treating an effluent of similar quality, it could provide an economic and sustainable alternative to conventional wetland treatment.

Ecofriendly degradation of sulfonated diazo dye C.I. Reactive Green 19A using Micrococcus glutamicus NCIM-2168.

PubMed

Saratale, R G; Saratale, G D; Chang, J S; Govindwar, S P

2009-09-01

Micrococcus glutamicus NCIM-2168 exhibited complete decolorization and degradation of C.I. Reactive Green 19A (an initial concentration of 50 mg l(-1)) within 42 h at temperature 37 degrees C and pH 8, under static condition. Extent of mineralization was determined with total organic carbon (TOC) and chemical oxygen demand (COD) measurement, showing a satisfactory reduction of TOC (72%) and COD (66%) within 42 h. Enzyme studies shows involvement of oxidoreductive enzymes in decolorization/degradation process. Analytical studies of the extracted metabolites confirmed the significant degradation of Reactive Green 19A into various metabolites. The microbial toxicity and phytotoxicity assay revealed that the degradation of Reactive Green 19A produced nontoxic metabolites. In addition, the M. glutamicus strain was applied to decolorize a mixture of ten reactive dyes showing a 63% decolorization (in terms of decrease in ADMI value) within 72 h, along with 48% and 42% reduction in TOC and COD under static condition.

Physical and oxidative removal of organics during Fenton treatment of mature municipal landfill leachate.

PubMed

Deng, Yang

2007-07-19

Municipal landfill leachate, especially mature leachate, may disrupt the performance of moderately-sized municipal activated sludge wastewater treatment plants, and likewise tend to be recalcitrant to biological pretreatment. Recently, Fenton methods have been investigated for chemical treatment or pre-treatment of mature leachate. In this paper, the results of laboratory tests to determine the roles of oxidation and coagulation in reducing the organic content of mature leachate during Fenton treatment are presented. The efficiencies of chemical oxygen demand (COD) oxidation and coagulation were tested, and the ratio of COD removal by oxidation to that by coagulation was assessed, under various operating conditions. Low initial pH, appropriate relative and absolute Fenton reagent dosages, aeration, and stepwise addition of reagents increased COD removal by oxidation and the importance of oxidation relative to coagulation. Simultaneous aeration and stepwise reagent addition allowed comparable treatment without initial acidification pH, due to the generation of acidic organic intermediates and the continuous input of CO2. On the other hand, high COD oxidation efficiency and low ferrous dosage inhibited COD removal by coagulation. At significantly high oxidation efficiency, overall COD reduction decrease slightly due to low coagulation efficiency. Under the most favorable conditions (initial pH 3, molar ratio [H(2)O(2)]/[Fe2+]=3, [H2O2]=240 mM, and six dosing steps), 61% of the initial COD was removed, and the ratio of COD removal oxidation to coagulation was 0.75. Results highlighted the synergistic roles of oxidation and coagulation in Fenton treatment of mature leachate, and the role of oxidation in controlling the efficiency of removal of COD by coagulation.

Interpreting the effect of increasing COD loading rates on the performance of a pre-anoxic MBBR system: implications on the attached and suspended biomass dynamics and nitrification-denitrification activity.

PubMed

Lima, P S; Dezotti, M; Bassin, J P

2016-06-01

A pre-anoxic MBBR system was subjected to increasing organic loading rates up to 18 gCOD/(m(2) day). At 3 gCOD/(m(2) day), most of the incoming organic matter was removed via denitrification. However, at higher loads, anoxic COD removal became limited by the nitrite/nitrate supply from the aerobic reactor, which assumed an important role in this conversion. Despite the application of low dissolved oxygen (DO) levels (<2 mg/L) in this tank, nitrification was observed to be nearly complete until 8 gCOD/(m(2) day). As the organic input was increased, the maximum specific nitrifying activity gradually declined. Activity tests suggested that an oxygen-limited environment was established in the biofilm. At lower loads [3-8 gCOD/(m(2) day)], the nitrification product obtained was affected by the DO concentration, whereas from 16 to 21 gCOD/(m(2) day), nitrite/nitrate profiles were likely associated with microbial stratification in the biofilm. The results also indicated that the role of the suspended biomass in the overall nitrification and denitrification can be very significant in high loaded MBBRs and should not be neglected, even at low HRTs.

Fractionation of wastewater characteristics for modelling of Firle Sewage Treatment Works, Harare, Zimbabwe

NASA Astrophysics Data System (ADS)

Muserere, Simon Takawira; Hoko, Zvikomborero; Nhapi, Innocent

Varying conditions are required for different species of microorganisms for the complex biological processes taking place within the activated sludge treatment system. It is against the requirement to manage this complex dynamic system that computer simulators were developed to aid in optimising activated sludge treatment processes. These computer simulators require calibration with quality data input that include wastewater fractionation among others. Thus, this research fractionated raw sewage, at Firle Sewage Treatment Works (STW), for calibration of the BioWin simulation model. Firle STW is a 3-stage activated sludge system. Wastewater characteristics of importance for activated sludge process design can be grouped into carbonaceous, nitrogenous and phosphorus compounds. Division of the substrates and compounds into their constituent fractions is called fractionation and is a valuable tool for process assessment. Fractionation can be carried out using bioassay methods or much simpler physico-chemical methods. The bioassay methods require considerable experience with experimental activated sludge systems and associated measurement techniques while the physico-chemical methods are straight forward. Plant raw wastewater fractionation was carried out through two 14-day campaign periods, the first being from 3 to 16 July 2013 and the second was from 1 to 14 October 2013. According to the Zimbabwean Environmental Management Act, and based on the sensitivity of its catchment, Firle STW effluent discharge regulatory standards in mg/L are COD (<60), TN (<10), ammonia (<0.2), and TP (<1). On the other hand Firle STW Unit 4 effluent quality results based on City of Harare records in mg/L during the period of study were COD (90 ± 35), TN (9.0 ± 3.0), ammonia (0.2 ± 0.4) and TP (3.0 ± 1.0). The raw sewage parameter concentrations measured during the study in mg/L and fractions for raw sewage respectively were as follows total COD (680 ± 37), slowly biodegradable COD (456 ± 23), (0.7), readily biodegradable COD (131 ± 11), (0.2), soluble unbiodegradable COD (40 ± 3), (0.06), particulate unbiodegradable COD (53 ± 3) (0.08), total TKN (40 ± 4) mg/L, ammonia (28 ± 6), (0.68), organically bound nitrogen (12 ± 2), (0.32), TP (15 ± 1.4), orthophosphates (9.6 ± 1.4), (0.64), and organically bound TP (5.4 ± 1.4), (0.36), soluble unbiodegradable TP (0.4 ± 0), (0.03), particulate unbiodegradable TP (0.05 ± 0), (0.003). Thus, wastewater at Firle STW was found to be highly biodegradable suggesting optimisation of biological nutrient removal process will generally achieve effluent regulatory standards compliance. Thus, opportunities for plant optimisation do exist of which modelling with the use of a simulator is recommended to achieve recommended effluent standards in addition to reduction of operating costs.

Improved solubilization of activated sludge by ozonation in pressure cycles.

PubMed

Cheng, Chia-Jung; Hong, P K Andy; Lin, Cheng-Fang

2012-05-01

The generation of a large volume of activated sludge (AS) from wastewater treatment has increasingly become a great burden on the environment. Anaerobic digestion is routinely practiced for excess waste sludge; however, the process retention time is long because of kinetic limitation in the hydrolysis step. We tested the feasibility of applying ozone in pressure cycles to enhance the disintegration and solubilization of AS with the goal to prepare them for digestion using reduced ozone dose and contact time. The AS was subjected to repetitive pressure cycles in a closed vessel in which an ozone gas mixture was compressed into the slurry to reach 1040 kPa in the headspace to be followed by rapid venting. For a returned AS with total COD (tCOD) of 8200 mg L(-1), a dose of 0.01 gO(3)g(-1) total suspended solids (TSS) delivered via 20 pressure cycles within 16 min resulted in a 37-fold increase of the sCOD/tCOD ratio (due to increased soluble COD, i.e. sCOD) and a 25% reduction of TSS, in comparison to a dose of 0.08 gO(3)g(-1) TSS via bubbling contact over 15 min that resulted in a 15-fold increase of the sCOD/tCOD ratio and a 12% reduction of TSS. Sludge solubilization was evidenced by increased dissolved contents of total phosphorous (from 10 to 64 mg L(-1)), total nitrogen (from 14 to 120 mg L(-1)), and protein (from <15 to 39 mg L(-1)) in the sludge suspension after treatment, indicating significant solubilization of AS. Copyright © 2012 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.

The effect of COD loading on the granule-based enhanced biological phosphorus removal system and the recoverability.

PubMed

Yu, Shenjing; Sun, Peide; Zheng, Wei; Chen, Lujun; Zheng, Xiongliu; Han, Jingyi; Yan, Tao

2014-11-01

In this study, the effect of varied COD loading (200, 400, 500, 600 and 800 mg L(-1)) on stability and recoverability of granule-based enhanced biological phosphorus removal (EBPR) system was investigated during continuously 53-d operation. Results showed that COD loading higher than 500 mg L(-1) could obviously deteriorate the granular EBPR system and result in sludge bulking with filamentous bacteria. High COD loading also changed the transformation patterns of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process of polyphosphate-accumulating organisms (PAOs) and inhibited the EPS secretion, which completely destroyed the stability and integrality of granules. Results of FISH indicated that glycogen-accumulating organisms (GAOs) and other microorganisms had a competitive advantage over PAOs with higher COD loading. The community composition and EBPR performance were recovered irreversibly in long time operation when COD loading was higher than 500 mg L(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Variation in organic matter and water color in Lake Mälaren during the past 70 years.

PubMed

Johansson, L; Temnerud, J; Abrahamsson, J; Berggren Kleja, D

2010-03-01

Interest in long time series of organic matter data has recently increased due to concerns about the effects of global climate change on aquatic ecosystems. This study presents and evaluates unique time series of chemical oxygen demand (COD) and water color from Lake Malaren, Sweden, stretching almost seven decades (1935-2004). A negative linear trend was found in COD, but not in water color. The decrease was mainly due to installation of sewage works around 1970. Time series of COD and water color had cyclic pattern. It was strongest for COD, with 23 years periodicity. Similar periodicity observed in air temperature and precipitation in Sweden has been attributed to the North Atlantic Oscillation index and solar system orbit, suggesting that COD in Lake Mälaren is partly derived from algae. Discharge influenced water color more than COD, possibly because water color consists of colored substances brought into the lake from surrounding soils.

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.

Response surface methodology for the optimization of sludge solubilization by ultrasonic pre-treatment

NASA Astrophysics Data System (ADS)

Zheng, Mingyue; Zhang, Xiaohui; Lu, Peng; Cao, Qiguang; Yuan, Yuan; Yue, Mingxing; Fu, Yiwei; Wu, Libin

2018-02-01

The present study examines the optimization of the ultrasonic pre-treatment conditions with response surface experimental design in terms of sludge disintegration efficiency (solubilisation of organic components). Ultrasonic pre-treatment for the maximum solubilization with residual sludge enhanced the SCOD release. Optimization of the ultrasonic pre-treatment was conducted through a Box-Behnken design (three variables, a total of 17 experiments) to determine the effects of three independent variables (power, residence time and TS) on COD solubilization of sludge. The optimal COD was obtained at 17349.4mg/L, when the power was 534.67W, the time was 10.77, and TS was 2%, while the SE of this condition was 28792J/kg TS.

Pollution profile and biodegradation characteristics of fur-suede processing effluents.

PubMed

Yildiz Töre, G; Insel, G; Ubay Cokgör, E; Ferlier, E; Kabdaşli, I; Orhon, D

2011-07-01

This study investigated the effect of stream segregation on the biodegradation characteristics of wastewaters generated by fur-suede processing. It was conducted on a plant located in an organized industrial district in Turkey. A detailed in-plant analysis of the process profile and the resulting pollution profile in terms of significant parameters indicated the characteristics of a strong wastewater with a maximum total COD of 4285 mg L(-1), despite the excessive wastewater generation of 205 m3 (ton skin)(-1). Respirometric analysis by model calibration yielded slow biodegradation kinetics and showed that around 50% of the particulate organics were utilized at a rate similar to that of endogenous respiration. A similar analysis on the segregated wastewater streams suggested that biodegradation of the plant effluent is controlled largely by the initial washing/pickling operations. The effect of other effluent streams was not significant due to their relatively low contribution to the overall organic load. The respirometric tests showed that the biodegradation kinetics of the joint treatment plant influent of the district were substantially improved and exhibited typical levels reported for tannery wastewater, so that the inhibitory impact was suppressed to a great extent by dilution and mixing with effluents of the other plants. The chemical treatment step in the joint treatment plant removed the majority of the particulate organics so that 80% of the available COD was utilized in the oxygen uptake rate (OUR) test, a ratio quite compatible with the biodegradable COD fractions of tannery wastewater. Consequently, process kinetics and especially the hydrolysis rate appeared to be significantly improved.

Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition.

PubMed

Liu, Zhan-Guang; Zhou, Xue-Fei; Zhang, Ya-Lei; Zhu, Hong-Guang

2012-01-01

The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700m(3) chicken-manure continuous stirred tank reactor (CSTR). A 12.3L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35±1°C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5kg-COD/m(3)d over a hydraulic retention time of 1.5d, a maximum volumetric biogas production rate of 1.2m(3)/m(3)d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250mg/L) at an influent pH of 8.5-9. Copyright © 2011 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.

Use of Fenton reaction for the treatment of leachate from composting of different wastes.

PubMed

Trujillo, Daniel; Font, Xavier; Sánchez, Antoni

2006-11-02

The oxidation of leachate coming from the composting of two organic wastes (wastewater sludge and organic fraction of municipal solid wastes) using the Fenton's reagent was studied using different ratios [Fe(2+)]/[COD](0) and maintaining a ratio [H(2)O(2)]/[COD](0) equal to 1. The optimal conditions for Fenton reaction were found at a ratio [Fe(2+)]/[COD](0) equal to 0.1. Both leachates were significantly oxidized under these conditions in terms of COD removal (77 and 75% for leachate from wastewater sludge composting and leachate from organic fraction of municipal solid wastes, respectively) and BOD(5) removal (90 and 98% for leachate from wastewater sludge composting and leachate from organic fraction of municipal solid wastes, respectively). Fenton's reagent was found to oxidize preferably biodegradable organic matter of leachate. In consequence, a decrease in the biodegradability of leachates was observed after Fenton treatment for both leachates. Nevertheless, Fenton reaction proved to be a feasible technique for the oxidation of the leachate under study, and it can be considered a suitable treatment for this type of wastewaters.

Investigation of soluble microbial products in a full-scale UASB reactor running at low organic loading rate.

PubMed

Zhou, Weili; Wu, Bingtao; She, Qianhong; Chi, Lina; Zhang, Zhenjia

2009-07-01

Investigation on a full-scale UASB treating industrial wastewater at a low organic loading rate (OLR) was conducted. Excellent treatment performance was achieved when treating the evaporator condensate of distillery wastewater at the OLR of less than 1 kg COD/m(3)d. Anaerobic effluent could be discharged without further treatment, which saved energy and running cost considerably. GC-MS analysis showed that the soluble microbial products (SMPs) were decreased to a low level at the low OLR. The main SMP in the anaerobic effluent were long chain carbohydrates and esters, accounting for 55-65% of the total organic matters. Anaerobic SMP was more complex than the aerobic ones. Soluble COD, protein and polysaccharide showed an obvious decrease at the sludge layer from 10 to 15m despite the low MLSS/MLVSS content. Methanogens were found to be predominant in this layer, which indicated that the methanogens might be the main consumers of the SMP in anaerobic reactors. Economic comparison confirmed that the anaerobic treatment at low OLR could be a good option.

A modified method for COD determination of solid waste, using a commercial COD kit and an adapted disposable weighing support.

PubMed

André, L; Pauss, A; Ribeiro, T

2017-03-01

The chemical oxygen demand (COD) is an essential parameter in waste management, particularly when monitoring wet anaerobic digestion processes. An adapted method to determine COD was developed for solid waste (total solids >15%). This method used commercial COD tubes and did not require sample dilution. A homemade plastic weighing support was used to transfer the solid sample into COD tubes. Potassium hydrogen phthalate and glucose used as standards showed an excellent repeatability. A small underestimation of the theoretical COD value (standard values around 5% lower than theoretical values) was also observed, mainly due to the intrinsic COD of the weighing support and to measurement uncertainties. The adapted COD method was tested using various solid wastes in the range of 1-8 mg COD , determining the COD of dried and ground cellulose, cattle manure, straw and a mixed-substrate sample. This new adapted method could be used to monitor and design dry anaerobic digestion processes.

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.

The Effect of COD Concentration Containing Leaves Litter, Canteen and Composite Waste to the Performance of Solid Phase Microbial Fuel Cell (SMFC)

NASA Astrophysics Data System (ADS)

Samudro, Ganjar; Syafrudin; Nugraha, Winardi Dwi; Sutrisno, Endro; Priyambada, Ika Bagus; Muthi'ah, Hilma; Sinaga, Glory Natalia; Hakiem, Rahmat Tubagus

2018-02-01

This research is conducted to analyze and determine the optimum of COD concentration containing leaves litter, canteen and composite waste to power density and COD removal efficiency as the indicator of SMFC performance. COD as the one of organic matter parameters perform as substrate, nutrient and dominating the whole process of SMFC. Leaves litter and canteen based food waste were obtained from TPST UNDIP in Semarang and treated in SMFC reactor. Its reactor was designed 2 liter volume and equipped by homemade graphene electrodes that were utilized at the surface of organic waste as cathode and in a half of reactor height as anode. COD concentration was initially characterized and became variations of initial COD concentration. Waste volume was maintained 2/3 of volume of reactor. Bacteria sources as the important process factor in SMFC were obtained from river sediment which contain bacteroides and exoelectrogenic bacteria. Temperature and pH were not maintained while power density and COD concentration were periodically observed and measured during 44 days. The results showed that power density up to 4 mW/m2 and COD removal efficiency performance up to 70% were reached by leaves litter, canteen and composite waste at days 11 up to days 44 days. Leaves litter contain 16,567 mg COD/l providing higher COD removal efficiency reached approximately 87.67%, more stable power density reached approximately 4.71 mW/m2, and faster optimum time in the third day than canteen based food waste and composite waste. High COD removal efficiency has not yet resulted in high power density.

Laboratory-scale membrane up-concentration and co-anaerobic digestion for energy recovery from sewage and kitchen waste.

PubMed

Tuyet, Nguyen Thi; Dan, Nguyen Phuoc; Vu, Nguyen Cong; Trung, Nguyen Le Hoang; Thanh, Bui Xuan; De Wever, Heleen; Goemans, Marcel; Diels, Ludo

2016-01-01

This study assessed an alternative concept for co-treatment of sewage and organic kitchen waste in Vietnam. The goal was to apply direct membrane filtration for sewage treatment to generate a permeate that is suitable for discharge. The obtained chemical oxygen demand (COD) concentrations in the permeate of ultrafiltration tests were indeed under the limit value (50 mg/L) of the local municipal discharge standards. The COD of the concentrate was 5.4 times higher than that of the initial feed. These concentrated organics were then co-digested with organic kitchen wastes at an organic loading rate of 2.0 kg VS/m(3).d. The volumetric biogas production of the digester was 1.94 ± 0.34 m(3)/m(3).d. The recovered carbon, in terms of methane gas, accounted for 50% of the total carbon input of the integrated system. Consequently, an electrical production of 64 Wh/capita/d can be obtained when applying the proposed technology with the current wastes generated in Ho Chi Minh City. Thus, it is an approach with great potential in terms of energy recovery and waste treatment.

Coproduction of hydrogen and methane via anaerobic fermentation of cornstalk waste in continuous stirred tank reactor integrated with up-flow anaerobic sludge bed.

PubMed

Cheng, Xi-Yu; Li, Qian; Liu, Chun-Zhao

2012-06-01

A 10 L continuous stirred tank reactor (CSTR) system was developed for a two-stage hydrogen fermentation process with an integrated alkaline treatment. The maximum hydrogen production rate reached 218.5 mL/L h at a cornstalk concentration of 30 g/L, and the total hydrogen yield and volumetric hydrogen production rate reached 58.0 mL/g-cornstalk and 0.55-0.57 L/L d, respectively. A 10 L up-flow anaerobic sludge bed (UASB) was used for continuous methane fermentation of the effluents obtained from the two-stage hydrogen fermentation. At the optimal organic loading rate of 15.0 g-COD/Ld, the COD removal efficiency and volumetric biogas production rate reached 83.3% and 4.6L/Ld, respectively. Total methane yield reached 200.9 mL/g-cornstalk in anaerobic fermentation with the effluents and alkaline hydrolysate. As a result, the total energy recovery by coproduction of hydrogen and methane with anaerobic fermentation of cornstalk reached 67.1%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Aerobic granulation in a sequencing batch reactor (SBR) for industrial wastewater treatment.

PubMed

Inizan, M; Freval, A; Cigana, J; Meinhold, J

2005-01-01

Aerobic granulation seems to be an a attractive process for COD removal from industrial wastewater, characterised by a high content of soluble organic compounds. In order to evaluate the practical aspects of the process, comparative experimental tests are performed on synthetic and on industrial wastewater, originating from pharmaceutical industry. Two pilot plants are operated as sequencing batch bubble columns. Focus was put on the feasibility of the process for high COD removal and on its operational procedure. For both wastewaters, a rapid formation of aerobic granules is observed along with a high COD removal rate. Granule characteristics are quite similar with respect to the two types of wastewater. It seems that filamentous bacteria are part of the granule structure and that phosphorus precipitation can play an important role in granule formation. For both wastewaters similar removal performances for dissolved biodegradable COD are observed (> 95%). However, a relatively high concentration of suspended solids in the outlet deteriorates the performance with regard to total COD removal. Biomass detachment seems to play a non-negligible role in the current set-up. After a stable operational phase the variation of the pharmaceutical wastewater caused a destabilisation and loss of the granules, despite the control for balanced nutrient supply. The first results with real industrial wastewater demonstrate the feasibility of this innovative process. However, special attention has to be paid to the critical aspects such as granule stability as well as the economic competitiveness, which both will need further investigation and evaluation.

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.

Anaerobic digestion of wastewater from the fruit juice industry: experiments and modeling.

PubMed

Zerrouki, Souhaib; Rihani, Rachida; Bentahar, Fatiha; Belkacemi, Khaled

2015-01-01

Anaerobic digestion of wastewater from the fruit juice industry was carried out in a batch digester. To study the effect of the pH values as well as the nutrient medium on the fermentation process, different parameters were monitored under mesophilic temperature, such as cumulative biogas volume, chemical oxygen demand (COD), total sugar, and biomass growth. It was found that for all cases, the COD concentration decreased with time. The lowest value reached was obtained when the nutrient medium was added; it was about 110 g/L after 480 h. In such cases, the COD removal reached about 80%; the highest cumulative biogas volume of about 5,515.8 NmL was reached after 480 h testing; and the lowest value reached was about 2,862.3 NmL in the case of peach-substrate containing sodium sulfite. The addition of nutrient medium improved the cumulative biogas production as well as the COD abatement. Measurement of the biogas composition highlighted three gaseous components, namely, methane (56.52%), carbon dioxide (20.14%), and hydrogen sulfide (23.34%). The modified Gompertz equation and the first-order kinetic model were used to describe the cumulative biogas production and the organic matter removal, respectively. A good agreement was found between simulated and experimental data.

Removal of the 2-mercaptobenotiazole from model wastewater by ozonation.

PubMed

Derco, Jan; Kassai, Angelika; Melicher, Michal; Dudas, Jozef

2014-01-01

The feasibility of ozonation process for 2-mercaptobenzothiazole (2-MBT) removal follows from results of ozonation of the model wastewater. Total removal of 2-MBT was observed after 20 minutes of ozonation. Very good reproducibility of repeated ozonation trials including sampling and analysis was observed. However, the majority of dissolved organic carbon (DOC) and chemical oxygen demand (COD) remained in the reaction mixture. Benzothiazole (BT) and 2-hydroxybenzothiazole (OBT) intermediates were identified during degradation of 2-MBT with ozone. In addition to the above benzothiazole derivatives, the creation of some other organic compounds follows from results of mass balance. The best fits of experimental data were obtained using the first kinetic model for 2-MBT and zero-order kinetic model for COD and DOC. The reaction time of 60 minutes can be considered as effective with regard to controlled oxidation in order to increase a portion of partially oxidized substances. Higher biodegradability and lower toxicity of ozonation products on respiration activity of activated sludge microorganisms was observed at higher ozonation time.

Removal of the 2-Mercaptobenotiazole from Model Wastewater by Ozonation

PubMed Central

Kassai, Angelika

2014-01-01

The feasibility of ozonation process for 2-mercaptobenzothiazole (2-MBT) removal follows from results of ozonation of the model wastewater. Total removal of 2-MBT was observed after 20 minutes of ozonation. Very good reproducibility of repeated ozonation trials including sampling and analysis was observed. However, the majority of dissolved organic carbon (DOC) and chemical oxygen demand (COD) remained in the reaction mixture. Benzothiazole (BT) and 2-hydroxybenzothiazole (OBT) intermediates were identified during degradation of 2-MBT with ozone. In addition to the above benzothiazole derivatives, the creation of some other organic compounds follows from results of mass balance. The best fits of experimental data were obtained using the first kinetic model for 2-MBT and zero-order kinetic model for COD and DOC. The reaction time of 60 minutes can be considered as effective with regard to controlled oxidation in order to increase a portion of partially oxidized substances. Higher biodegradability and lower toxicity of ozonation products on respiration activity of activated sludge microorganisms was observed at higher ozonation time. PMID:24578619

A new strategy to maximize organic matter valorization in municipalities: Combination of urban wastewater with kitchen food waste and its treatment with AnMBR technology.

PubMed

Moñino, P; Aguado, D; Barat, R; Jiménez, E; Giménez, J B; Seco, A; Ferrer, J

2017-04-01

The aim of this study was to evaluate the feasibility of treating the kitchen food waste (FW) jointly with urban wastewater (WW) in a wastewater treatment plant (WWTP) by anaerobic membrane technology (AnMBR). The experience was carried out in six different periods in an AnMBR pilot-plant for a total of 536days, varying the SRT, HRT and the food waste penetration factor (PF) of food waste disposers. The results showed increased methane production of up to 190% at 70days SRT, 24h HRT and 80% PF, compared with WW treatment only. FW COD and biodegradability were higher than in WW, so that the incorporation of FW into the treatment increases the organic load and the methane production and reduces sludge production (0.142 vs 0.614kgVSSkgremovedCOD -1 , at 70days SRT, 24h HRT and 80% PF, as compared to WW treatment only). Copyright © 2017 Elsevier Ltd. All rights reserved.

A single-stage biological process for municipal sewage treatment in tourist areas.

PubMed

Di Iaconi, C; De Sanctis, M; Lopez, A

2014-11-01

This pilot scale study aims to test the effectiveness of an innovative compact biological system (SBBGR - Sequencing Batch Biofilter Granular Reactor) for treating municipal wastewater in tourist areas characterised by intense seasonal water demand and wastewater discharge. The results obtained after a long term operation of 463 days have shown that the proposed system is able to assure average removal efficiencies higher than 90% for COD (chemical oxygen demand), total suspended solids and TKN (total Kjeldahl nitrogen) independently of the influent concentration values and organic loading, which ranged from 0.2 to 5.1 kgCOD/m(3)biofilter.d Furthermore, the plant showed a high degree of operation flexibility and stability in response to the organic load variations occurring in tourist areas. In fact, no significant deterioration in the plant's effluent quality was observed even during a sudden several-fold increase in organic loading. High nitrogen removal efficiencies (80%, on average) were also achieved thanks to the establishment of simultaneous nitrification-denitrification process favoured by the plant's high biomass concentration and operating conditions. Finally, the system was characterized by an excess sludge production much lower (60-80% lower) than that of conventional biological systems operating without a primary clarifier. An acceptable level of stabilization of excess sludge was also obtained so that a further stabilization process was no longer required. Copyright © 2014 Elsevier Ltd. All rights reserved.

Destroying chemical wastes in commercial-scale incinerators. Final report

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

Adams, J.W.; Cunningham, N.J.; Harris, J.C.

1976-12-01

Tests were conducted at Zimpro, Inc., Rothschild, Wisconsin, to determine the effectiveness of wet air oxidation for destruction of two selected aqueous industrial wastes: coke plant waste and Amiben (herbicide) manufacturing waste. A pilot scale facility was tested for the coke plant waste with less than 6g/1 total solids and 5.5 g/1 Biological Oxygen Demand (BOD5), chemical compounds such as cyanides, phenols and cresols were 99% destroyed; BOD5 and Chemical Oxygen Demand (COD) were reduced by about 90%. The concentration of quinoline was reduced by only 66%. Estimated costs for treating 2,120 cu m/day of coke waste were: $12.3 MMmore » capital investment and $9.90/cu m total operating cost. For the Amiben waste, with 55 g/1 total solids and 31 g/1 BOD5, the test showed greater than 99% destruction of the major organic waste components, dichloronitrobenzoic acids, with about 10% conversion to an intermediate degradation product, dichloronitrobenzene. The BOD5 and COD were reduced by 90% and 82%, respectively. Estimated costs for treating 151 cu m/day of Amiben waste were: $2.2 MM capital investment and $18.00/cu m total operating cost.« less

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.

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).

Mutagenicity of drinking water sampled from the Yangtze River and Hanshui River (Wuhan section) and correlations with water quality parameters.

PubMed

Lv, Xuemin; Lu, Yi; Yang, Xiaoming; Dong, Xiaorong; Ma, Kunpeng; Xiao, Sanhua; Wang, Yazhou; Tang, Fei

2015-03-31

A total of 54 water samples were collected during three different hydrologic periods (level period, wet period, and dry period) from Plant A and Plant B (a source for Yangtze River and Hanshui River water, respectively), and several water parameters, such as chemical oxygen demand (COD), turbidity, and total organic carbon (TOC), were simultaneously analyzed. The mutagenicity of the water samples was evaluated using the Ames test with Salmonella typhimurium strains TA98 and TA100. According to the results, the organic compounds in the water were largely frame-shift mutagens, as positive results were found for most of the tests using TA98. All of the finished water samples exhibited stronger mutagenicity than the relative raw and distribution water samples, with water samples collected from Plant B presenting stronger mutagenic strength than those from Plant A. The finished water samples from Plant A displayed a seasonal-dependent variation. Water parameters including COD (r = 0.599, P = 0.009), TOC (r = 0.681, P = 0.02), UV254 (r = 0.711, P = 0.001), and total nitrogen (r = 0.570, P = 0.014) exhibited good correlations with mutagenicity (TA98), at 2.0 L/plate, which bolsters the argument of the importance of using mutagenicity as a new parameter to assess the quality of drinking water.

Mutagenicity of drinking water sampled from the Yangtze River and Hanshui River (Wuhan section) and correlations with water quality parameters

PubMed Central

Lv, Xuemin; Lu, Yi; Yang, Xiaoming; Dong, Xiaorong; Ma, Kunpeng; Xiao, Sanhua; Wang, Yazhou; Tang, Fei

2015-01-01

A total of 54 water samples were collected during three different hydrologic periods (level period, wet period, and dry period) from Plant A and Plant B (a source for Yangtze River and Hanshui River water, respectively), and several water parameters, such as chemical oxygen demand (COD), turbidity, and total organic carbon (TOC), were simultaneously analyzed. The mutagenicity of the water samples was evaluated using the Ames test with Salmonella typhimurium strains TA98 and TA100. According to the results, the organic compounds in the water were largely frame-shift mutagens, as positive results were found for most of the tests using TA98. All of the finished water samples exhibited stronger mutagenicity than the relative raw and distribution water samples, with water samples collected from Plant B presenting stronger mutagenic strength than those from Plant A. The finished water samples from Plant A displayed a seasonal-dependent variation. Water parameters including COD (r = 0.599, P = 0.009), TOC (r = 0.681, P = 0.02), UV254 (r = 0.711, P = 0.001), and total nitrogen (r = 0.570, P = 0.014) exhibited good correlations with mutagenicity (TA98), at 2.0 L/plate, which bolsters the argument of the importance of using mutagenicity as a new parameter to assess the quality of drinking water. PMID:25825837

Performance evaluation of a full-scale innovative swine waste-to-energy system.

PubMed

Xu, Jiele; Adair, Charles W; Deshusses, Marc A

2016-09-01

Intensive monitoring was carried out to evaluate the performance of a full-scale innovative swine waste-to-energy system at a commercial swine farm with 8640 heads of swine. Detailed mass balances over each unit of the system showed that the system, which includes a 7600m(3) anaerobic digester, a 65-kW microturbine, and a 4200m(3) aeration basin, was able to remove up to 92% of the chemical oxygen demand (COD), 99% of the biological oxygen demand (BOD), 77% of the total nitrogen (TN), and 82% of the total phosphorous (TP) discharged into the system as fresh pig waste. The overall biogas yield based on the COD input was 64% of the maximum theoretical, a value that indicates that even greater environmental benefits could be obtained with process optimization. Overall, the characterization of the materials fluxes in the system provides a greater understanding of the fate of organics and nutrients in large scale animal waste management systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic digestibility of marine microalgae Phaeodactylum tricornutum in a lab-scale anaerobic membrane bioreactor.

PubMed

Zamalloa, Carlos; De Vrieze, Jo; Boon, Nico; Verstraete, Willy

2012-01-01

The biomass of industrially grown Phaeodactylum tricornutum was subjected in a novel way to bio-methanation at 33°C, i.e., in an anaerobic membrane bioreactor (AnMBR) at a hydraulic retention time of 2.5 days, at solid retention times of 20 to 10 days and at loading rates in the range of 2.6-5.9 g biomass-COD L(-1) day(-1) with membrane fluxes ranging from 1 to 0.8 L m(-2) h(-1). The total COD recovered as biogas was in the order of 52%. The input suspension was converted to a clear effluent rich in total ammonium nitrogen (546 mg TAN L(-1)) and phosphate (141 mg PO(4)-P L(-1)) usable as liquid fertilizer. The microbial community richness, dynamics, and organization in the reactor were interpreted using the microbial resource management approach. The AnMBR communities were found to be moderate in species richness and low in dynamics and community organization relative to UASB and conventional CSTR sludges. Quantitative polymerase chain reaction analysis revealed that Methanosaeta sp. was the dominant acetoclastic methanogen species followed by Methanosarcina sp. This work demonstrated that the use of AnMBR for the digestion of algal biomass is possible. The fact that some 50% of the organic matter is not liquefied means that the algal particulates in the digestate constitute a considerable fraction which should be valorized properly, for instance as slow release organic fertilizer. Overall, 1 kg of algae dry matter (DM) could be valorized in the form of biogas ( euro 2.07), N and P in the effluent (euro 0.02) and N and P in the digestate (euro 0.04), thus totaling about euro 2.13 per kilogram algae DM.

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.

Organics and nitrogen removal from textile auxiliaries wastewater with A2O-MBR in a pilot-scale.

PubMed

Sun, Faqian; Sun, Bin; Hu, Jian; He, Yangyang; Wu, Weixiang

2015-04-09

The removal of organic compounds and nitrogen in an anaerobic-anoxic-aerobic membrane bioreactor process (A(2)O-MBR) for treatment of textile auxiliaries (TA) wastewater was investigated. The results show that the average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH4(+)-N) and total nitrogen (TN) were about 119, 3 and 48 mg/L under an internal recycle ratio of 1.5. The average removal efficiency of COD, NH4(+)-N and TN were 87%, 96% and 55%, respectively. Gas chromatograph-mass spectrometer analysis indicated that, although as much as 121 different types of organic compounds were present in the TA wastewater, only 20 kinds of refractory organic compounds were found in the MBR effluent, which could be used as indicators of effluents from this kind of industrial wastewater. Scanning electron microscopy analysis revealed that bacterial foulants were significant contributors to membrane fouling. An examination of foulants components by wavelength dispersive X-ray fluorescence showed that the combination of organic foulants and inorganic compounds enhanced the formation of gel layer and thus caused membrane fouling. The results will provide valuable information for optimizing the design and operation of wastewater treatment system in the textile industry. Copyright © 2015 Elsevier B.V. All rights reserved.

"XANSONS for COD": a new small BOINC project in crystallography

NASA Astrophysics Data System (ADS)

Neverov, Vladislav S.; Khrapov, Nikolay P.

2018-04-01

"XANSONS for COD" (http://xansons4cod.com) is a new BOINC project aimed at creating the open-access database of simulated x-ray and neutron powder diffraction patterns for nanocrystalline phase of materials from the collection of the Crystallography Open Database (COD). The project uses original open-source software XaNSoNS to simulate diffraction patterns on CPU and GPU. This paper describes the scientific problem this project solves, the project's internal structure, its operation principles and organization of the final database.

Gas production in anaerobic dark-fermentation processes from agriculture solid waste

NASA Astrophysics Data System (ADS)

Sriwuryandari, L.; Priantoro, E. A.; Sintawardani, N.

2017-03-01

Approximately, Bandung produces agricultural solid waste of 1549 ton/day. This wastes consist of wet-organic matter and can be used for bio-gas production. The research aimed to apply the available agricultural solid waste for bio-hydrogen. Biogas production was done by a serial of batches anaerobic fermentation using mix-culture bacteria as the active microorganism. Fermentation was carried out inside a 30 L bioreactor at room temperature. The analyzed parameters were of pH, total gas, temperature, and COD. Result showed that from 3 kg/day of organic wastes, various total gases of O2, CH4, H2, CO2, and CnHn,O2 was produced.

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.

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.

Anaerobic treatability of high oil and grease rendering wastewater.

PubMed

Nakhla, George; Al-Sabawi, Mustafa; Bassi, Amerjeet; Liu, Victor

2003-08-29

This study evaluated the use of a new biosurfactant, BOD-Balance, derived from cactus for the treatment of oil-and-grease-laden rendering wastewater anaerobically. Batch laboratory experimental results and preliminary full-scale data are presented. The biosurfactant affected a significant increase in the COD degradation rate for the raw wastewater. However, after reduction of the oil and grease (O&G) by dissolved air flotation, the biosurfactant did not exhibit any advantages. Modeling of the data indicated that various COD fractions, i.e. both soluble and particulate as well as total COD at various testing conditions conformed well to both zero-order and first-order models. The biosurfactant affected a 164-238 and 164-247% increase in COD and particulate COD biodegradation rate for the raw wastewater. The reduction of O&G concentration to <800 mg/l increased total and soluble COD degradation rates by 106%. Results from the full-scale mesophilic anaerobic digestion system indicated that the addition of the biosurfactant at doses of 130-200 mg/l decreased O&G concentrations from 66,300 to 10,200 mg/l over a 2-month-period.

Colour and organic removal of biologically treated coffee curing wastewater by electrochemical oxidation method.

PubMed

Bejankiwar, Rajesh S; Lokesh, K S; Gowda, T P Halappa

2003-05-01

The treatment of biologically treated wastewater of coffee-curing industry by the electrochemical oxidation using steel anode was investigated. Bench-scale experiments were conducted for activated sludge process on raw wastewater and the treated effluents were further treated by electrochemical oxidation method for its colour and organic content removal. The efficiency of the process was determined in terms of removal percentage of COD, BOD and colour during the course of reaction. Several operating parameters like time, pH and current density were examined to ascertain their effects on the treatment efficiency. Steel anode was found to be effective for the COD and colour removal with anode efficiency of 0.118 kgCOD x h(-1) x A(-1) x m(-2) and energy consumption 20.61 kWh x kg(-1) of COD at pH 9. The decrease in pH from 9 to 3 found to increase the anode efficiency from 0.118 kgCOD x h(-1) x A(-1) x m(-2) to 0.144 kWh x kg(-1) of COD while decrease the energy consumption from 20.61 kWh x kg(-1) of COD to 12.86 kWh x kg(-1) of COD. The pH of 5 was considered an ideal from the present treatment process as it avoids the addition of chemicals for neutralization of treated effluents and also economical with respect to energy consumption. An empirical relation developed for relationship between applied current density and COD removal efficiency showed strong predictive capability with coefficient of determination of 96.5%.

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.

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.

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.

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.

Ulva biomass as a co-substrate for stable anaerobic digestion of spent coffee grounds in continuous mode.

PubMed

Kim, Jaai; Kim, Hakchan; Lee, Changsoo

2017-10-01

Ulva biomass was evaluated as a co-substrate for anaerobic digestion of spent coffee grounds at varying organic loads (0.7-1.6g chemical oxygen demand (COD)/Ld) and substrate compositions. Co-digestion with Ulva (25%, COD basis) proved beneficial for SCG biomethanation in both terms of process performance and stability. The beneficial effect is much more pronounced at higher organic and hydraulic loads, with the highest COD removal and methane yield being 51.8% and 0.19L/g COD fed, respectively. The reactor microbial community structure changed dynamically during the experiment, and a dominance shift from hydrogenotrophic to aceticlastic methanogens occurred with increase in organic loading rate. Network analysis provides a comprehensive view of the microbial interactions involved in the system and confirms a direct positive correlation between Ulva input and methane productivity. A group of populations, including Methanobacterium- and Methanoculleus-related methanogens, was identified as a possible indicator for monitoring the biomethanation performance. Copyright © 2017 Elsevier Ltd. 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

Characterisation of winery wastewater from continuous flow settling basins and waste stabilisation ponds over the course of 1 year: implications for biological wastewater treatment and land application.

PubMed

Welz, P J; Holtman, G; Haldenwang, R; le Roes-Hill, M

2016-11-01

Wineries generate 0.2 to 4 L of wastewater per litre of wine produced. Many cellars make use of irrigation as a means of disposal, either directly or after storage. In order to consider the potential downstream impacts of storage/no storage, this study critically compared the seasonal organic and inorganic composition of fresh winery effluent with effluent that had been stored in waste stabilisation ponds. Ethanol and short chain volatile fatty acids were the main contributors to chemical oxygen demand (COD), with average concentrations of 2,086 and 882 mgCOD/L, respectively. Total phenolics were typically present in concentrations <100 mg/L. The concentration of sodium from cleaning agents was higher in the non-crush season, while the converse was true for organics. The effluent was nitrogen-deficient for biological treatment, with COD:N ratios of 0.09 to 1.2. There was an accumulation of propionic and butyric acid during storage. The composition of the pond effluent was more stable in character, and it is possible that bacterial and algal nitrogen fixation in such systems may enhance biological wastewater treatment by natural nitrogen supplementation. It is therefore recommended that if land requirements can be met, winery effluent should be stored in ponds prior to treatment.

Playerload Variables are Sensitive to Changes in Direction and Not Related to Collision Workloads in Rugby League Match-Play.

PubMed

Hulin, Billy T; Gabbett, Tim J; Johnston, Rich D; Jenkins, David G

2018-03-15

Determine: 1) how change of direction (COD) workloads influence PlayerLoad variables when controlling total distance covered, and 2) relationships among collision workloads and PlayerLoad variables during rugby league match-play. Participants completed 3 protocols (crossover design) consisting of 10 repetitions of a 60 m effort in 15 s. The difference between each protocol was the COD demands required to complete 1 repetition; no COD (SL), 1 x 180º COD (1COD), or 3 x 180º COD (3COD). During rugby league matches, relationships among collision workloads, tri-axial PlayerLoad (PLVM), anterior-posterior + medio-lateral PlayerLoad (PL2D), and PLVM accumulated at locomotor velocities below 2 m.sec -1 (i.e. PLSLOW) were examined using Pearson correlations (r) with coefficients of determination (R 2 ). Comparing 3COD to SL drills: PLVM.min -1 (d = 1.50 ± 0.49, large, likelihood = 100%, almost certainly), PL2D.min -1 (d = 1.38 ± 0.53, large, likelihood = 100%, almost certainly), and PLSLOW.min -1 (d = 1.69 ± 0.40, large, likelihood = 100%, almost certainly) were greater. Collisions.min -1 demonstrated a distinct (i.e. R 2 <0.50) relationship from PLVM.min -1 (R 2 = 0.30, r = 0.55), and PL2D.min -1 (R 2 = 0.37, r = 0.61). Total distance.min 1 demonstrated a very large relationship with PLVM.min -1 (R 2 = 0.62, r = 0.79), and PL2D.min -1 (R 2 = 0.57, r = 0.76). PlayerLoad variables demonstrate: 1) large increases as COD demands intensify, 2) separate relationships from collision workloads, and 3) moderate to very large relationships with total distance during match-play. PlayerLoad variables should be used with caution to measure collision workloads in team sport.

Fate of LCFA in the co-digestion of cow manure, food waste and discontinuous addition of oil.

PubMed

Neves, L; Oliveira, R; Alves, M M

2009-12-01

Different concentrations of oily waste were added in a discontinuous mode and recurrently to anaerobic continuous stirred tank reactors fed with cow manure and food waste. Four continuous stirred tank reactors were run in parallel. A control reactor (R1) received no additional oil and R2, R3 and R4 received increasing concentrations of oil in two different experimental approaches. First, the lipids composition was forced to change suddenly, in three moments, without changing the total chemical oxygen demand (COD) fed to the reactors. The only long chain fatty acid (LCFA) detected onto the R1 solid matrix was palmitic acid (C16:0). Nevertheless in the solid matrix of R2, R3 and R4C16:0 and stearic acid were detected. For occasional increase in the oil concentration up to 7.7gCOD(oil)/L(reactor) (55% Oil(COD)/Total(COD)) no statistical differences were detected between the reactors, in terms of methane production, effluent soluble COD, effluent volatile fatty acids and total and volatile solids removal. Therefore this experiment allowed to conclude that cow manure-food waste co-digestion presents sufficient buffer capacity to endure solid-associated LCFA concentration up to 20-25gCOD-LCFA/kgTS. In a second experiment higher concentrations of oil were added, raising occasionally the concentration in the reactors to 9, 12, 15 and 18gCOD(oil)/L(reactor). All pulses had a positive effect in methane production, with the exception of the highest oil pulse concentration, that persistently impaired the reactor performance. This experiment demonstrates that threshold values for LCFA and C16:0 accumulation onto the solid matrix, of about 180-220gCOD-LCFA/kgTS and 120-150gCOD-C16:0/kgTS, should not be surpassed in order to prevent persistent reactor failure, as occurs in some full scale co-digestion plants.

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.

Iron-based catalysts for photocatalytic ozonation of some emerging pollutants of wastewater.

PubMed

Espejo, Azahara; Beltrán, Fernando J; Rivas, Francisco J; García-Araya, Juan F; Gimeno, Olga

2015-01-01

A synthetic secondary effluent containing an aqueous mixture of emerging contaminants (ECs) has been treated by photocatalytic ozonation using Fe(3+) or Fe3O4 as catalysts and black light lamps as the radiation source. For comparative purposes, ECs have also been treated by ultraviolet radiation (UVA radiation, black light) and ozonation (pH 3 and 7). With the exception of UVA radiation, O3-based processes lead to the total removal of ECs in the mixture. The time taken to achieve complete degradation depends on the oxidation process applied. Ozonation at pH 3 is the most effective technique. The addition of iron based catalysts results in a slight inhibition of the parent compounds degradation rate. However, a positive effect is experienced when measuring the total organic carbon (TOC) and the chemical oxygen demand (COD) removals. Photocatalytic oxidation in the presence of Fe(3+) leads to 81% and 88% of TOC and COD elimination, respectively, compared to only 23% and 29% of TOC and COD removals achieved by single ozonation. The RCT concept has been used to predict the theoretical ECs profiles in the homogeneous photocatalytic oxidation process studied. Treated wastewater effluent was toxic to Daphnia magna when Fe(3+) was used in photocatalytic ozonation. In this case, toxicity was likely due to the ferryoxalate formed in the process. Single ozonation significantly reduced the toxicity of the treated wastewater.

Electrolytic treatment of Standard Malaysian Rubber process wastewater.

PubMed

Vijayaraghavan, Krishnan; Ahmad, Desa; Yazid, Ahmad Yuzri Ahmad

2008-01-31

A new method of Standard Malaysian Rubber (SMR) process wastewater treatment was developed based on in situ hypochlorous acid generation. The hypochlorous acid was generated in an undivided electrolytic cell consisting of two sets of graphite as anode and stainless sheets as cathode. The generated hypochlorous acid served as an oxidizing agent to destroy the organic matter present in the SMR wastewater. For an influent COD concentration of 2960 mg/L at an initial pH 4.5+/-0.1, current density 74.5 mA/cm(2), sodium chloride content 3% and electrolysis period of 75 min, resulted in the following residual values pH 7.5, COD 87 mg/L, BOD(5) 60 mg/L, TOC 65 mg/L, total chlorine 146 mg/L, turbidity 7 NTU and temperature 48 degrees C, respectively. In the case of 2% sodium chloride as an electrolyte for the above said operating condition resulted in the following values namely: pH 7.2, COD 165 mg/L, BOD(5) 105 mg/L, TOC 120 mg/L, total chlorine 120 mg/L, turbidity 27 NTU and temperature 53 degrees C, respectively. The energy requirement were found to be 30 and 46 Wh/L, while treating 24 L of SMR wastewater at 2 and 3% sodium chloride concentration at a current density 74.5 mA/cm(2). The observed energy difference was due to the improved conductivity at high sodium chloride content.

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

An Assessment of Potential Soviet Responses to Evolving Theater Nuclear Systems.

DTIC Science & Technology

1987-06-05

ORGANIZATION REPORT NUMIBER(S) 5 MONITORING ORGANIZAODN REPORT NUMNBER(S) 6a NAM OFPERFORMING ORGANIZATION fib OFFICE SYMBOL 7& NAME OF MONITORING... ORGANIZATION 6C. ADDRESS (Oty. State, and ZIP Cod.) 7b ADDRESSC,ty, State, and ZIP Cod.) Vicksburg, MS 39180-0631 Ba AMEOF UNDNG SPOSORNG8b OFFICE SYMBOL...9 PROCuREMENT INSR~UMENT IDENTiCICATtON N%BER ORGANIZATION (If appliabe USAm op fEgnes DN’o~)1 Bk. ADDRESS (City, State, and ZIP Code) 10 SOURCE OF

Influence of organic load rate (OLR) on the hydrolytic acidification of 2-butenal manufacture wastewater and analysis of bacterial community structure.

PubMed

Song, Guangqing; Xi, Hongbo; Zhou, Yuexi; Fu, Liya; Xing, Xin; Wu, Changyong

2017-11-01

The influence of organic loading rate (OLR) on the performance of hydrolytic acidification process for treating 2-butenal manufacture wastewater was comprehensively studied, while its impact on microbial community was thoroughly investigated. The results demonstrated that over 21.0% of the average COD removal rate was observed in the range of OLR from 0.52 to 3.98g COD/L·d, whereas it reduced to 15.3% with increasing OLR to 6.09g COD/L·d. The acidification degree dramatically decreased from 17.1% to 4.7% when OLR increased from 3.98 to 6.09g COD/L·d. In addition, the removal rates of three kinds of typical matters were less than 65% at the OLR 6.09g COD/L·d. Illumina MiSeq sequencing revealed that Proteobacteria, Chloroflexi, Firmicutes, and Bacteroidetes were dominant phyla at different OLRs. Finally, multivariate analysis suggested that the genera Longilinea and T78 had a positive correlation with the degradation of three kinds of typical matters and COD removal rates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Solids Retention Time on the Denitrification Potential of Anaerobically Digested Swine Waste

NASA Astrophysics Data System (ADS)

Kinyua, Maureen Njoki

Three continuously stirred tank reactors (CSTR) were operated in semi continuous mode treating swine waste using anaerobic digestion. The reactors were used to test the effect of solid retention time (SRT) on CH4 yield, total ammonia nitrogen (TAN) concentrations, % volatile solids (VS), chemical oxygen demand (COD) and volatile fatty acids (VFA) removal, readily biodegradable COD concentration and the denitrification potential for the effluent in a biological nutrient removal (BNR) system. During Phase I of the study, the three reactors were operated at the same 28 day SRT for 16 weeks. SRTs were then changed during the 12 week Phase II period. The SRTs studied were 14, 21 and 28 days, with the same organic loading rate (OLR) of 1.88 ± 0.2 kg VS/ m3-day. The reactor with the lowest SRT (14 days) had the highest VS and VFA removal at 73.6 and 67.6% and lowest TAN concentration at 0.78 g NH4+-N/L, followed by the 21 day and 28 day reactors. This was likely due to the fast microbial growth rates and substrate utilization rates in this reactor compared with the other two. The 14 day reactor had the highest CH4 yield at 0.33 m3CH 4/kg VS added and readily biodegradable COD concentration at 0.93 COD/L. The variations in CH4 yield and readily biodegradable COD concentrations between the three reactors were not statistically significant. Denitrification potential for the reactors was 1.20, 0.73 and 0.56 g COD/g N for 14, 21 and 28 day reactors, respectively, and the differences were statistically significant. None of the reactors achieved a denitrification potential of 5 g COD/g N, the amount required to use effluent of anaerobically digested swine waste as an internal carbon source in a BNR. This was attributed to operating conditions such as freezing and thawing of the raw swine waste that maximized CH4 yield and lowered the readily biodegradable COD concentration. In addition the 14 day reactor had low TAN concentrations thus increasing the denitrification potential of the centrate from that reactor.

40 CFR 419.42 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... exceed 15 mg/l oil and grease and 110 mg/l total organic carbon (TOC) based upon an analysis of any... 110 mg/l TOC is not commingled or treated with any other type of wastewater, the quantity of... exceeds 1,000 mg/l (1,000 ppm), the permitting authority may substitute TOC as a parameter in lieu of COD...

40 CFR 419.52 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... mg/l total organic carbon (TOC) based upon an analysis of any single grab or composite sample. (2) If... contaminated runoff which exceeds 15 mg/l oil and grease or 110 mg/l TOC is not commingled or treated with any... substitute TOC as a parameter in lieu of COD. A TOC effluent limitation shall be based on effluent data from...

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.

Dissolved Organic In Natural and Polluted Waters: Methodology and Results of Running Control of Chemical Oxygen Demand (cod) For The Inland and Marine Aquatic System

NASA Astrophysics Data System (ADS)

Melentyev, K. V.; Worontsov, A. M.

Current control of dissolved organic matter in natural and waste waters is the definition traditionally of chemical oxygen demand (COD) -- one of the basic parameters of quality of water. According to the International Standard (ISO 6060), it requires not less than one hour, while in many cases the operative information about amount of dissolved organic matter in aquatic environments have importance for prevention of an emergency. The standard method is applicable to waters with meaning of COD above 30 mg O2/l and, as the chloride ion prevents, it could be difficult for assessment of organic matter in sea water. Besides it is based on dichromate oxidation of the sum of organic substances in strong acid conditions at the presence of silver and mercury, that resulted in formation toxic pollutants. Till now attempts of automation of the COD definition in aquatic system were limited, basically, to duplication of the technology submitted the above standard (automatic COD analyzers "SERES Co."-- France, or "Tsvet Co." - Russia). The system of ozone-chemiluminescence automatic control of organic matter in water (CS COD) is offered and designed. Its based on the ozone oxidation of these substances in flowing water system and measurement arising from luminescent effects. CS COD works in real time. An instrument uses for reaction the atmospheric air, doesn't require fill of reagents and doesn't make new toxic pollutants. The system was tested in laboratory, and biochemical control of organic matter in water samples gathered from the river Neva and other polluted inland water areas and basins in St. Petersburg region was fulfilled (distilled water was used as "zero" media). The results of systematization of these measurements are presented. The new special ozone generator and flowing reactor for real-time running control of different waters in natural conditions were developed, and several series of large - scale field experiments onboard research ship were provided. Comprehensive study of the natural waters (including biohydro-chemical parameters control) for large part of the inland waterway St. Petersburg ­ White Sea (river Neva - Ladoga Lake ­ river Svir - Onega Lake ­ Petrozavodsk) was provided in frame the experimental voyage onboard the m/v «St. Peterburg» (J uly 1998 and June 1999). The results of organic matter charting for the different water masses for vast water basin in the northwestern of Russia were analyzed and classified. The arrangement of dissolved organic for the largest in Europe lakes Ladoga and Onega is analyzed in comparison with hydrological and meteorological processes and phenomena, including thermal regime modification. Spatial and temporal (seasonal and annual) transformation of organic matter for these water basins are studied. Aquatic environment conditions of the coastal zones, different bays and gulfs more pressed by livestock and agricultural farms, and industry are assessed also. According to the shipborne data more polluted water areas are the Svir Bay (Ladoga Lake) and Petrozavodskaya Guba (Onega Lake). These results are well correlated with in situ data and literature data. Thus, first time in practice is carried out the running control of a COD and spatial profile of the organic matter for different natural waters. Accuracy of measurements in comparison with traditional approaches and new technologies (including ideas and results practical application of sonoluminiscence of dissolved organic) are discussed also. The modification of CS COD was used for the cont rol of dissolved organic in different marine aquatic system. Sea water samples and preserved ice cores, gathered in the Barents, White and Kara Seas, were investigated. Probes of saltish and brackish-water (as ice cores) from the estuary of great Siberian rivers (Ob Bay and Yenisey Gulf) were analyzed in laboratory (biochemical analysis of these probes was fulfilled also). It was demonstrat ed that CS COD system can be used till range a salinity 25-33% ?, that opens to use this method for operative assessment of water parameters and dissolved organic control in different types of sea water. The result of classification of spatial and temporal modification of the organic matter in the different part of Russian Arctic are presented. As a near-term perspective we plan to connect CS COD system with the State Regional Network of Ecological Control (SRNEC). Another task is organizing comprehensive study of dissolved organic and biochemistry of sea waters at the White Sea: long-term in situ measurements will started in March'02 at the Biological Station of Moscow State University in Kandalaksha (Karelya).

Thermochemical pretreatments of organic fraction of municipal solid waste from a mechanical-biological treatment plant.

PubMed

Álvarez-Gallego, Carlos José; Fdez-Güelfo, Luis Alberto; de los Ángeles Romero Aguilar, María; Romero García, Luis Isidoro

2015-02-09

The organic fraction of municipal solid waste (OFMSW) usually contains high lignocellulosic and fatty fractions. These fractions are well-known to be a hard biodegradable substrate for biological treatments and its presence involves limitations on the performance of anaerobic processes. To avoid this, thermochemical pretreatments have been applied on the OFMSW coming from a full-scale mechanical-biological treatment (MBT) plant, in order to pre-hydrolyze the waste and improve the organic matter solubilisation. To study the solubilisation yield, the increments of soluble organic matter have been measured in terms of dissolved organic carbon (DOC), soluble chemical oxygen demand (sCOD), total volatile fatty acids (TVFA) and acidogenic substrate as carbon (ASC). The process variables analyzed were temperature, pressure and NaOH dosage. The levels of work for each variable were three: 160-180-200 °C, 3.5-5.0-6.5 bar and 2-3-4 g NaOH/L. In addition, the pretreatment time was also modified among 15 and 120 min. The best conditions for organic matter solubilisation were 160 °C, 3 g NaOH/L, 6.5 bar and 30 min, with yields in terms of DOC, sCOD, TVFA and ASC of 176%, 123%, 119% and 178% respectively. Thus, predictably the application of this pretreatment in these optimum conditions could improve the H2 production during the subsequent Dark Fermentation process.

Treatment of poultry slaughterhouse wastewater using a static granular bed reactor (SGBR) coupled with ultrafiltration (UF) membrane system.

PubMed

Basitere, M; Rinquest, Z; Njoya, M; Sheldon, M S; Ntwampe, S K O

2017-07-01

The South African poultry industry has grown exponentially in recent years due to an increased demand for their products. As a result, poultry plants consume large volumes of high quality water to ensure that hygienically safe poultry products are produced. Furthermore, poultry industries generate high strength wastewater, which can be treated successfully at low cost using anaerobic digesters. In this study, the performance of a bench-scale mesophilic static granular bed reactor (SGBR) containing fully anaerobic granules coupled with an ultrafiltration (UF) membrane system, as a post-treatment system, was investigated. The poultry slaughterhouse wastewater was characterized by a chemical oxygen demand (COD) range between 1,223 and 9,695mg/L, average biological oxygen demand of 2,375mg/L and average fats, oil and grease (FOG) of 554mg/L. The SGBR anaerobic reactor was operated for 9 weeks at different hydraulic retention times (HRTs), i.e. 55 and 40 h, with an average organic loading rate (OLR) of 1.01 and 3.14g COD/L.day. The SGBR results showed an average COD, total suspended solids (TSS) and FOG removal of 93%, 95% and 90% respectively, for both OLR. The UF post-treatment results showed an average of COD, TSS and FOG removal of 64%, 88% and 48%, respectively. The overall COD, TSS and FOG removal of the system (SGBR and UF membrane) was 98%, 99.8%, and 92.4%, respectively. The results of the combined SGBR reactor coupled with the UF membrane showed a potential to ensure environmentally friendly treatment of poultry slaughterhouse wastewater.

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.

Preliminary study on optimization of pH, oxidant and catalyst dose for high COD content: solar parabolic trough collector

PubMed Central

2013-01-01

In the present study, solar photocatalytic oxidation has been investigated through laboratory experiments as an alternative to conventional secondary treatment for the organic content reduction of high COD wastewater. Experiments have been performed on synthetic high COD wastewater for solar photocatalytic oxidation using a parabolic trough reactor. Parameters affecting the oxidation of organics have been investigated. The experimental design followed the sequence of dark adsorption studies of organics, followed by photolytic studies (in absence of catalyst) and finally photocatalytic studies in presence and absence of additional oxidant (H2O2). All the experimental studies have been performed at pH values of 2, 4, 6,8,10 and the initial pH value of the wastewater (normal pH). For photocatalytic studies, TiO2 has been used as a photocatalyst. Optimization of catalyst dose, pH and H2O2 concentration has been done. Maximum reduction of organic content was observed at the normal pH value of the wastewater (pH = 6.8). The reaction rate was significantly enhanced in presence of hydrogen peroxide. The optimum pH other than the Normal was in the alkaline range. Acidic pH was not found to be favourable for organic content reduction. pH was found to be a dominant factor affecting reaction rate even in presence of H2O2 as an additional oxidant. Also, the solar detoxification process was effective in treating a waste with a COD level of more than 7500 mg/L, which is a otherwise a difficult waste to treat. It can therefore be used as a treatment step in the high organic wastewater treatment during the primary stage also as it effectively reduces the COD content by 86%. PMID:23369352

Effect of operational conditions on the degradation of organic matter and development of microalgae-bacteria consortia when treating swine slurry.

PubMed

González-Fernández, Cristina; Riaño-Irazábal, Berta; Molinuevo-Salces, Beatriz; Blanco, Saúl; García-González, Maria Cruz

2011-05-01

There is great controversy regarding the best substrate (fresh or anaerobically digested swine slurry) for the development of microalgae-bacteria consortia. This study aims to elucidate the best substrate by assessing biomass productivity, microorganism predominance, and their ability for organic matter removal. In addition to the different substrates, different operational conditions and influent strengths were evaluated. Increasing organic matter content when favourable temperature and illumination conditions were present improved biomass production. However, these conditions were not favourable for microalgal growth, but they were favourable for bacteria. Regardless of the operational conditions, reactors fed with fresh slurry not only resulted in the highest biomass productivity, but also the greatest removal of total and soluble chemical oxygen demand (COD). On the other hand, reactors fed with digested slurry showed biomass productivity and COD removal values lower than those obtained for reactors fed with fresh slurry, most probably due to the recalcitrant nature of the former. Nevertheless, digested slurry was the substrate more appropriate for microalgae growth under harsh operational conditions (16 °C and 9-h illumination) at low influent strength and optimum operational conditions (30 °C and 24-h illumination) at higher influent strength.

[Municipal biowaste thermal-hydrolysis and ASBR anaerobic digestion].

PubMed

Hou, Hua-hua; Wang, Wei; Hu, Song; Xu, Yi-xian

2010-02-01

Thermal-hydrolysis can remarkably improve the solid organics dissolving efficiency of urban biomass waste, and anaerobic sequencing batch reactor (ASBR) was used to improve the efficiency of urban biomass waste anaerobic digestion. The optimum thermal-hydrolysis temperature and holding time was 175 degrees C and 60 min, the volatile suspended solid (VSS) dissolving ratio of kitchen waste, fruit-and-vegetable waste and sludge were 31.3%, 31.9% and 49.7%, respectively. Two ASBR and one continuous-flow stirred tank reactor (CSTR) were started at hydraulic retention time (HRT) = 20 d, COD organic loading rate (OLR) = 3.2-3.6 kg/(m3 x d). The biogas production volumes were 5656 mL/d(A1), 6335 mL/d(A2) and 3 103 mL/d(CSTR), respectively; VSS degradation ratios were 45.3% (A1), 50.87% (A2), 20.81% (CSTR), and the total COD (TCOD) removal rates were 88.1% (A1), 90% (A2), 72.6% (CSTR). In ASBR, organic solid and anaerobic microorganism were remained in the reactor during settling period. When HRT was 20 d, the solid retention time (SRT) was over 130 d, which made ASBR higher efficiency than CSTR.

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.

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.

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.

[Assessment of production of eggs of Eastern Baltic cod (Gadus morhua callarias L.) on the basis of long-term ichthyoplankton data].

PubMed

Karaseva, E M

2011-01-01

Proceeding from long-term data on the numbers of eggs of cod in ichthyoplankton, the total annual production of cod eggs at four main spawning grounds of the Baltic Sea was calculated. It was shown that the long-term fluctuations of cod egg production were positively related to the dynamics of the volume of waters coming to the Baltic Sea in years of the North Sea advections. It is suggested that this dependence was determined by a set of adaptations providing the extension of cod reproduction upon the improvement of the environment.

Influence of nutrients on biomass evolution in an upflow anaerobic sludge blanket reactor degrading sulfate-laden organics.

PubMed

Patidar, S K; Tare, Vinod

2004-01-01

This paper describes the effect of the nutrients iron (Fe), nickel (Ni), zinc (Zn), cobalt (Co), and molybdenum (Mo) on biomass evolution in an upflow anaerobic sludge blanket (UASB) reactor metabolizing synthetic sulfate-laden organics at varying operating conditions during a period of 540 days. A bench-scale model of a UASB reactor was operated at a temperature of 35 degrees C for a chemical oxygen demand-to-sulfate (COD/SO4(2-)) ratio of 8.59 to 2.0, a sulfate loading rate of 0.54 to 1.88 kg SO4(2-)/m3 x d, and an organic loading rate of 1.9 to 5.75 kg COD/m3 x d. Biomass was characterized in terms of total methanogenic activity, acetate-utilizing methanogenic activity, total sulfidogenic activity, acetate-utilizing sulfidogenic activity, and scanning electron microscopy (SEM). Nickel and cobalt limitation appears to affect the activity of hydrogen-utilizing methane-producing bacteria (HMPB) significantly without having an appreciable effect on the activity of acetate-utilizing methane-producing bacteria (AMPB). Nickel and cobalt supplementation resulted in increased availability and, consequently, restoration of biomass activity and process performance. Iron limitation and sulfidogenic conditions resulted in the growth of low-density, hollow, fragile granules that washed out, causing process instability and performance deterioration. Iron and cobalt supplementation indicated significant stimulation of AMPB with slight inhibition of HMPB. Examination of biomass through SEM indicated a population shift with dominance of sarcina-type organisms and the formation of hollow granules. Granule disintegration was observed toward the end of the study.

Disinfection and reduction of organic load of sewage water by electron beam radiation

NASA Astrophysics Data System (ADS)

Maruthi, Y. Avasn; Das, N. Lakshmana; Hossain, Kaizar; Sarma, K. S. S.; Rawat, K. P.; Sabharwal, S.

2011-09-01

The efficacy of electron beam radiation for the disinfection and reduction of organic load of sewage water was assessed with ILU-6 Accelerator at Radiation Technology Development Division of the Bhabha Atomic Research Centre, Mumbai India. The current problem on environmental health in relation to water pollution insists for the safe disposal of sewage water. In general, sewage water comprises heterogeneous organic based chemicals as well as pathogens. EB treatment of the wastewater has found to be very effective in reducing the pathogens as well as organic load. EB dose of 1.5 kGy was sufficient for complete elimination of total coli forms. The experimental results elucidated the reduction of biological oxygen demand—BOD (35 and 51.7%) in both inlet and outlet sewage samples. Similarly reduction of chemical oxygen demand—COD was observed (37.54 and 52.32%) in both sewage samples with respect to increase in irradiation doses (0.45-6 kGy). The present study demonstrated the potential of ionizing radiation for disinfection of sewage and to increase the water quality of the wastewater by decreasing BOD and COD. So, the irradiation sewage water can find its application either in agriculture for irrigation, in industry for cooling purpose and some selected domestic purposes.

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.

Comparison of the Northeast Arctic cod year class strength (at the age of 3+) with the SST anomalies in main spawning ground (the Norwegian Shelf Waters) by results of analysis satellite monitoring data during last years.

NASA Astrophysics Data System (ADS)

Vanyushin, George

2015-04-01

Continuous long-term database (1998-2014) on the sea surface temperature (SST) comprising results of regional satellite monitoring (the Norwegian and the Barents seas) is used to resolve several applied problems. Authors have analyzed indirect influence the SST (the NOAA satellite data) on modern cod total stock biomass (abundance of the Northeast Arctic cod at age 3+). In this study, we went on the consideration of the relationship between the SST anomalies for March-April in the main spawning ground of the cod off the Lofoten islands in the Norwegian Shelf Waters and forecasting assessment of future cod generation success and its future abundance of 3 year old. Mean monthly SST and SST anomalies are computed for the selected area on the basis of the weekly SST maps which made by using the NOAA satellites data for the period 1998-2014. Comparison of the SST anomalies in the main spawning ground with abundance of the cod year class at age 3+ shows that survival of the cod generations was inhibited on the whole as negative (below -0,1C) well as positive SST anomalies (above +1,3C) during March and April. Finally, the results indicate that poor and low middle generations of cod at age 3+ (2002, 2004, 2010) occurred in years with negative or extremely high positive the SST anomalies in the spawning area. The SST anomalies in years which were close to normal significances provide conditions for appearance middle or strong generations of cod (2001-2003, 2005-2009, 2011-2013). So, the SST and SST anomalies (by the NOAA satellite data) characterize of increase in input of warm Atlantic waters which form numerous eddies along the main stream thus creating favorable conditions for spawning and development of the cod larvae and fry and provide them with food stock, finally direct influence on forming total stock biomass of cod and helping its population forecast. Key words: satellite monitoring of SST, the Northeast Arctic cod, spawning ground, forecast of the cod year class strength at age 3+.

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.

Research progress of on-line automatic monitoring of chemical oxygen demand (COD) of water

NASA Astrophysics Data System (ADS)

Cai, Youfa; Fu, Xing; Gao, Xiaolu; Li, Lianyin

2018-02-01

With the increasingly stricter control of pollutant emission in China, the on-line automatic monitoring of water quality is particularly urgent. The chemical oxygen demand (COD) is a comprehensive index to measure the contamination caused by organic matters, and thus it is taken as one important index of energy-saving and emission reduction in China’s “Twelve-Five” program. So far, the COD on-line automatic monitoring instrument has played an important role in the field of sewage monitoring. This paper reviews the existing methods to achieve on-line automatic monitoring of COD, and on the basis, points out the future trend of the COD on-line automatic monitoring instruments.

Effect of volumetric organic loading on the nitrogen removal rate by immobilised activated sludge.

PubMed

Zielinska, M; Wojnowska-Baryla, I

2006-05-01

Activated sludge was immobilised in a porous ceramic carrier to create a stationary core of a bio-reactor. Municipal wastewater was treated in this reactor under varied conditions of volumetric organic loading rate (expressed by chemical oxygen demand (COD)) that were the following: 6.5, 8.0, 20.8, 48.8 g COD l(-1) d(-1). The rate constants of ammonification, nitrification and denitrification under aerobic conditions were determined. All rate constants increased with a growth in volumetric loading rate, but the highest loading value of 48.8 g COD l(-1) d(-1) limited the ammonification and nitrification rates.

Upflow anaerobic sludge blanket and aerated constructed wetlands for swine wastewater treatment: a pilot study.

PubMed

Masi, F; Rizzo, A; Martinuzzi, N; Wallace, S D; Van Oirschot, D; Salazzari, P; Meers, E; Bresciani, R

2017-07-01

Swine wastewater management is often affected by two main issues: a too high volume for optimal reuse as a fertilizer and a too high strength for an economically sustainable treatment by classical solutions. Hence, an innovative scheme has been tested to treat swine wastewater, combining a low cost anaerobic reactor, upflow anaerobic sludge blanket (UASB), with intensified constructed wetlands (aerated CWs) in a pilot scale experimental study. The swine wastewater described in this paper is produced by a swine production facility situated in North Italy. The scheme of the pilot plant consisted of: (i) canvas-based thickener; (ii) UASB; (iii) two intensified aerated vertical subsurface flow CWs in series; (iv) a horizontal flow subsurface CW. The influent wastewater quality has been defined for total suspended solids (TSS 25,025 ± 9,323 mg/l), organic carbon (chemical oxygen demand (COD) 29,350 ± 16,983 mg/l), total reduced nitrogen and ammonium (total Kjeldahl nitrogen (TKN) 1,783 ± 498 mg/l and N-NH 4 + 735 ± 251 mg/l) and total phosphorus (1,285 ± 270 mg/l), with nitrates almost absent. The overall system has shown excellent performances in terms of TSS, COD, N-NH 4 + and TKN removal efficiencies (99.9%, 99.6%, 99.5%, and 99.0%, respectively). Denitrification (N-NO 3 - effluent concentration equal to 614 ± 268 mg/l) did not meet the Italian quality standards for discharging in water bodies, mainly because the organic carbon was almost completely removed in the intensified CW beds.

Influence of different natural zeolite concentrations on the anaerobic digestion of piggery waste.

PubMed

Milán, Z; Sánchez, E; Weiland, P; Borja, R; Martín, A; Ilangovan, K

2001-10-01

The effect of different natural zeolite concentrations on the anaerobic digestion of piggery waste was studied. Natural zeolite doses in the range 0.2-10 g/l of wastewater were used in batch experiments, which were carried out at temperatures between 27 degrees C and 30 degrees C. Total chemical oxygen demand (COD), total and volatile solids, ammonia and organic nitrogen, pH, total volatile fatty acids (TVFA), alkalinity (Alk) and accumulative methane production were determined during 30 days of digestion. The anaerobic digestion process was favored by the addition of natural zeolite at doses between 2 and 4 g/l and increasingly inhibited at doses beyond 6 g/l. A first-order kinetic model of COD removal was used to determine the apparent kinetic constants of the process. The kinetic constant values increased with the zeolite amount up to a concentration of 4 g/l. The values of the maximum accumulative methane production (Gm) increased until zeolite concentrations of 2-4 g/l. The addition of zeolite reduced the values of the TVFA/ Alk ratio while increasing the pH values, and these facts could contribute to the process failure at zeolite doses of 10 g/l.

77 FR 14305 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Jig Gear in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-09

... Using Jig Gear in the Central Regulatory Area of the Gulf of Alaska AGENCY: National Marine Fisheries...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels using jig gear in the... season allowance of the 2012 Pacific cod total allowable catch apportioned to vessels using jig gear in...

77 FR 6683 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-09

... Using Pot Gear in the Western Regulatory Area of the Gulf of Alaska AGENCY: National Marine Fisheries...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels using pot gear in the... season allowance of the 2012 Pacific cod total allowable catch apportioned to vessels using pot gear in...

77 FR 8177 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-14

... Using Pot Gear in the Central Regulatory Area of the Gulf of Alaska AGENCY: National Marine Fisheries...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels using pot gear in the... season allowance of the 2012 Pacific cod total allowable catch apportioned to vessels using pot gear in...

75 FR 3874 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Participating in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-25

.... 0810141351-9087-02] RIN 0648-XT95 Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Participating in the Amendment 80 Limited Access Fishery in Bering Sea and Aleutian Islands Management Area... management area (BSAI). This action is necessary to prevent exceeding the 2010 Pacific cod total allowable...

77 FR 54838 - Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pacific Cod in the Western...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-06

.... 111207737-2141-02] RIN 0648-XC205 Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pacific Cod in the Western Regulatory Area of the Gulf of Alaska Management Area AGENCY: National Marine... Alaska management area. This action is necessary to allow the 2012 total allowable catch of Pacific cod...

Mercury and persistent organic pollutants in native and invading forage species of the Canadian Arctic: Consequences for food web dynamics.

PubMed

Pedro, Sara; Fisk, Aaron T; Tomy, Gregg T; Ferguson, Steven H; Hussey, Nigel E; Kessel, Steven T; McKinney, Melissa A

2017-10-01

Contaminant dynamics within Arctic marine food webs may be altered through the climate-driven northward invasions of temperate/boreal species. Here, we compare tissue concentrations of total mercury (THg) and legacy and emerging persistent organic pollutants (POPs) in native versus invading forage species sampled from 2012 to 2014 near Arviat, Clyde River, and Resolute Bay, NU, representing, low, mid- and high eastern Canadian Arctic regions, respectively. Concentrations of THg, legacy Σ-polychlorinated biphenyls (ΣPCB) and Σ-organochlorine (ΣOC) pesticides were detected in all forage species, whereas emerging halogenated flame retardants were detected in only a few individuals. Concentrations of major contaminant groups among regions did not vary for Arctic cod (Boreogadus saida), while for sculpin (Cottoidea) there was no clear latitudinal trend. Thus, considering interspecific variation, native sculpin and northern shrimp (Pandalus borealis) had the highest overall concentrations of THg (0.17 ± 0.02 and 0.21 ± 0.01 μg g -1 wet weight, respectively), ΣPCB (322 ± 35 and 245 ± 25 ng g -1 lipid weight (lw), respectively), and ΣOC (413 ± 38 and 734 ± 64 ng g -1 lw, respectively). Comparing the keystone native species, Arctic cod, to its 'replacement' species, capelin (Mallotus villosus) and sandlance (Ammodytes spp.), THg concentrations were higher in Arctic cod compared to capelin (p < 0.001), which was partly explained by differences in fish length. Conversely, capelin and sandlance had higher concentrations of most POPs than Arctic cod (p < 0.02). Neither feeding habitat (based on δ 13 C), trophic position (based on δ 15 N), nor fish length significantly explained these differences in POPs between Arctic cod, capelin and sandlance. Higher POPs concentrations, as well as variation in congener/compound patterns, in capelin and sandlance relative to Arctic cod seem, therefore, more likely related to a more "temperate"-type contaminant signature in the invaders. Nevertheless, the relatively small (up to two-fold) magnitude of these differences suggested limited effects of these ecological changes on contaminant uptake by Arctic piscivores. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of Microbial Growth by Protein Assay in an Air-Cathode Single Chamber Microbial Fuel Cell.

PubMed

Li, Na; Kakarla, Ramesh; Moon, Jung Mi; Min, Booki

2015-07-01

Microbial fuel cells (MFCs) have gathered attention as a novel bioenergy technology to simultaneously treat wastewater with less sludge production than the conventional activated sludge system. In two different operations of the MFC and aerobic process, microbial growth was determined by the protein assay method and their biomass yields using real wastewater were compared. The biomass yield on the anode electrode of the MFC was 0.02 g-COD-cell/g- COD-substrate and the anolyte planktonic biomass was 0.14 g-COD-cell/g-COD-substrate. An MFC without anode electrode resulted in the biomass yield of 0.07 ± 0.03 g-COD-cell/g-COD-substrate, suggesting that oxygen diffusion from the cathode possibly supported the microbial growth. In a comparative test, the biomass yield under aerobic environment was 0.46 ± 0.07 g-COD-cell/g-COD-substrate, which was about 3 times higher than the total biomass value in the MFC operation.

Effect of intermittent aeration strategies on treatment performance and microbial community of an IFAS reactor treating municipal waste water.

PubMed

Singh, Nitin Kumar; Bhatia, Akansha; Kazmi, Absar Ahmad

2017-11-01

This study investigated the effect of various intermittent aeration (IA) cycles on organics and nutrient removal, and microbial communities in an integrated fixed-film activated sludge (IFAS) reactor treating municipal waste water. Average effluent biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids, total nitrogen (TN) and total phosphorus (TP) values were noted as 20, 50, 30, 12 and 1.5 mgL -1 , respectively, in continuous aeration mode. A total of four operational conditions (run 1, continuous aeration; run 2, 150/30 min aeration on/off time; run 3, 120/60 min aeration on/off time and run 4, 90/60 min aeration on/off time) were investigated in IFAS reactor assessment. Among the all examined IA cycles, IA phase 2 gave the maximum COD and BOD removals with values recorded as 97% and 93.8%, respectively. With respect to nutrient removal (TN and TP), IA phase 1 was found to be optimum. Pathogen removal efficiency of present system was recorded as 90-95% during the three phases. With regard to settling characteristics, pilot showed poor settling during IA schedules, which was also evidenced by high sludge volume index values. Overall, IA could be used as a feasible way to improve the overall performance of IFAS system.

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.

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.

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.

Effect of gradual transition of substrate on performance of flat-panel air-cathode microbial fuel cells to treat domestic wastewater.

PubMed

Park, Younghyun; Park, Seonghwan; Nguyen, Van Khanh; Kim, Jung Rae; Kim, Hong Suck; Kim, Byung Goon; Yu, Jaecheul; Lee, Taeho

2017-02-01

In order to confirm the effects of the low conductivity and biodegradability of wastewater, flat-panel air-cathode microbial fuel cells (FA-MFCs) were operated by supplying substrates with different volume ratios of domestic wastewater mixed with an artificial medium: the artificial medium only, 25% wastewater, 50% wastewater, 75% wastewater, 100% of wastewater with 500mg-COD/L by adding acetate, and raw domestic wastewater (230mg-COD/L). With the increase of wastewater ratio, the maximum power density and organic removal efficiency decreased from 187 to 60W/m 3 and 51.5 to 37.4%, respectively, but the Coulombic efficiency was maintained in the range of 18.0-18.9%. The FA-MFCs could maintain their low internal resistances and overcome the decreasing conductivity. The acetate concentration was more important than the total organics for power production. This study suggests that the FA-MFC configuration has great applicability for practical applications when supplied by domestic wastewater with low conductivity and biodegradability. Copyright © 2016 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.

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.

78 FR 17884 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catcher Vessels Greater Than...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-25

... Catcher Vessels Greater Than or Equal to 50 Feet (15.2 Meters) Length Overall Using Hook-and-Line Gear in...: NMFS is prohibiting directed fishing for Pacific cod by catcher vessels (CVs) greater than or equal to... of the 2013 Pacific cod total allowable catch apportioned to CVs greater than or equal to 50 feet (15...

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.

Effects of intermittent aeration periods on a structured-bed reactor continuously fed on the post-treatment of sewage anaerobic effluent.

PubMed

Silva, Bruno Garcia; Damianovic, Márcia Helena Rissato Zamariolli; Foresti, Eugenio

2018-04-20

This study assessed the simultaneous nitrification and denitrification processes and remaining organic matter removal from anaerobic reactor effluent treating wastewater in a single reactor. A structured-bed reactor, with polyurethane foam as support media, was subjected to intermittent aeration and effluent recirculation. Aerated/non-aerated periods varied in the range of 2/1-1/3 h. The chemical oxygen demand (COD) in the effluent remained between 26 and 42 mg L -1 throughout all the aeration conditions. Aeration periods of 1/2 h removed 80 and 26% of Total Kjeldahl Nitrogen and Total Nitrogen, respectively. A low solid production was observed during the 300 days of operation, resulting in a solid retention time of 139 days. The results indicate that the non-aerated periods generated alkalinity that favored nitrification, maintaining low COD concentrations in the effluent. The structured bed reactor presented a low solid production and effluent loss below 20 mgSSV L -1 , similar to concentrations obtained in secondary decanters.

Kinetics and methane gas yields of selected C1 to C5 organic acids in anaerobic digestion.

PubMed

Yang, Yu; Chen, Qian; Guo, Jialiang; Hu, Zhiqiang

2015-12-15

Volatile fatty acids (VFAs) and other short-chain organic acids such as lactic and pyruvic acids are intermediates in anaerobic organic degradation. In this study, anaerobic degradation of seven organic acids in salt form was investigated, including formate (C1), acetate (C2), propionate (C3), pyruvate (C3), lactate (C3), butyrate (C4), and valerate (C5). Microbial growth kinetics on these organic acids were determined individually at 37 °C through batch anaerobic digestion tests by varying substrate concentrations from 250 to 4000 mg COD/L. The cumulative methane generation volume was determined real-time by respirometry coupled with gas chromatographic analysis while methane yield and related kinetics were calculated. The methane gas yields (fe, mg CH4 COD/mg substrate COD) from anaerobic degradation of formate, acetate, propionate, pyruvate, lactate, butyrate, and valerate were 0.44 ± 0.27, 0.58 ± 0.05, 0.53 ± 0.18, 0.24 ± 0.05, 0.17 ± 0.05, 0.43 ± 0.15, 0.49 ± 0.11, respectively. Anaerobic degradation of formate showed self-substrate inhibition at the concentrations above 3250 mg COD/L. Acetate, propionate, pyruvate, butyrate, lactate, and valerate did not inhibit methane production at the highest concentrations tested (i.e., 4000 mg COD/L). Microbes growing on acetate had the highest overall specific growth rate (0.30 d(-1)) in methane production. For comparison, the specific microbial growth rates on formate, propionate, pyruvate, butyrate, lactate, and valerate for methane production were 0.10, 0.06, 0.08, 0.07, 0.05, 0.15 d(-1), respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Microbiological, chemical and sensory spoilage analysis of raw Atlantic cod (Gadus morhua) stored under modified atmospheres.

PubMed

Kuuliala, L; Al Hage, Y; Ioannidis, A-G; Sader, M; Kerckhof, F-M; Vanderroost, M; Boon, N; De Baets, B; De Meulenaer, B; Ragaert, P; Devlieghere, F

2018-04-01

During fish spoilage, microbial metabolism leads to the production of volatile organic compounds (VOCs), characteristic off-odors and eventual consumer rejection. The aim of the present study was to contribute to the development of intelligent packaging technologies by identifying and quantifying VOCs that indicate spoilage of raw Atlantic cod (Gadus morhua) under atmospheres (%v/v CO 2 /O 2 /N 2 ) 60/40/0, 60/5/35 and air. Spoilage was examined by microbiological, chemical and sensory analyses over storage time at 4 or 8 °C. Selected-ion flow-tube mass spectrometry (SIFT-MS) was used for quantifying selected VOCs and amplicon sequencing of the 16S rRNA gene was used for the characterization of the cod microbiota. OTUs classified within the Photobacterium genus increased in relative abundance over time under all storage conditions, suggesting that Photobacterium contributed to spoilage and VOC production. The onset of exponential VOC concentration increase and sensory rejection occurred at high total plate counts (7-7.5 log). Monitoring of early spoilage thus calls for sensitivity for low VOC concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Grey water treatment in UASB reactor at ambient temperature.

PubMed

Elmitwalli, T A; Shalabi, M; Wendland, C; Otterpohl, R

2007-01-01

In this paper, the feasibility of grey water treatment in a UASB reactor was investigated. The batch recirculation experiments showed that a maximum total-COD removal of 79% can be obtained in grey-water treatment in the UASB reactor. The continuous operational results of a UASB reactor treating grey water at different hydraulic retention time (HRT) of 20, 12 and 8 hours at ambient temperature (14-24 degrees C) showed that 31-41% of total COD was removed. These results were significantly higher than that achieved by a septic tank (11-14%), the most common system for grey water pre-treatment, at HRT of 2-3 days. The relatively lower removal of total COD in the UASB reactor was mainly due to a higher amount of colloidal COD in the grey water, as compared to that reported in domestic wastewater. The grey water had a limited amount of nitrogen, which was mainly in particulate form (80-90%). The UASB reactor removed 24-36% and 10-24% of total nitrogen and total phosphorus, respectively, in the grey water, due to particulate nutrients removal by physical entrapment and sedimentation. The sludge characteristics of the UASB reactor showed that the system had stable performance and the recommended HRT for the reactor is 12 hours.

A comparative analysis of selected wastewater pretreatment processes in food industry

NASA Astrophysics Data System (ADS)

Jaszczyszyn, Katarzyna; Góra, Wojciech; Dymaczewski, Zbysław; Borowiak, Robert

2018-02-01

The article presents a comparative analysis of the classical coagulation with the iron sulphate and adsorption on bentonite for the pretreatment of wastewater in the food industry. As a result of the studies, chemical oxygen demand (COD) and total nitrogen (TN) reduction were found to be comparable in both technologies, and a 29% higher total phosphorus removal efficiency by the coagulation was observed. After the coagulation and adsorption processes, a significant difference between mineral and organic fraction in the sludge was found (49% and 51% for bentonite and 28% and 72% for iron sulphate, respectively).

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.

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.

Effect of White Charcoal on COD Reduction in Wastewater Treatment

NASA Astrophysics Data System (ADS)

Pijarn, Nuchanaporn; Butsee, Manipa; Buakul, Kanokwan; Seng, Hasan; Sribuarai, Tinnphat; Phonprasert, Pongtep; Taneeto, Kla; Atthameth, Prasertsil

2017-06-01

The objective of this study is to compare the COD reduction in wastewater between using coconut shell and coconut spathe white charcoal from Khlong Wat NongPra-Ong, Krathumbaen, SamutSakhon province, Thailand. The waste water samples were collected using composite sampling method. The experimental section can be divided into 2 parts. The first part was study the optimum of COD adsorption time using both white charcoals. The second part was study the optimum amount of white charcoal for chemical oxygen demand (COD) reduction. The pre-treatment of wastewater was examined in parameters include temperature, alkalinity (pH), conductivity, turbidity, suspended solid (SS), total dissolved solid (TDS), and COD. The results show that both white charcoals can reduce COD of wastewater. The pH of pre-treatment wastewater had pH 9 but post-treatment wastewaters using both white charcoals have pH 8. The COD of pre-treatment wastewater had COD as 258 mg/L but post-treatment wastewater using coconut shell white charcoal had COD steady at 40 mg/L in 30 min and the amount of white charcoals 4 g. The COD of post-treatment wastewater using coconut spathe white charcoal had COD steady at 71 mg/L in 30 min and the amount of white charcoals 4 g. Therefore comparison of COD reduction between coconut shell white charcoal versus coconut spathe white charcoal found that the coconut shell white charcoal had efficiency for COD reduction better than coconut spathe white charcoal.

Treatment of domestic wastewater using conventional and baffled septic tanks.

PubMed

Nasr, Fayza Aly; Mikhaeil, Basem

2013-01-01

The main theme of the study was a comparative study of domestic wastewater treatment using conventional and baffled septic tanks. The septic tanks were fed continuously with domestic wastewater at three different hydraulic retention times (HRTs). The HRTs chosen were 24, 48 and 72 h with corresponding organic loads of 0.321, 0.436 and 0.885 kg chemical oxygen demand (COD) per m3 per day, respectively. The performance of the septic tanks at the three HRTs gave satisfactory results. For the conventional septic tank, COD removal was 53.4%, 56% and 65.3%, at an HRT of 24, 48 and 72 h, respectively, with residual COD of 412, 380 and 334mg/l, respectively. At HRTs of 72, 48 and 24 h, the following percentages removals were realized for: biochemical oxygen demand (BOD), 68.4%, 57, 53.5%; total suspended solid (TSS), 65.3%, 58.3, 55%; phosphorus, 29.3%, 26.9, 25.6%; total Kjeldahl nitrogen 26.8%, 20.8, 17.7%, respectively. On the contrary, ammonia concentrations increased by 7.1%, 5.2 and 4.2% under the same conditions. Consequently, the results showed that the removal of fecal coliform at all HRTs was less than one log. The two baffled septic tanks exhibited superior results at HRTs of 72, 48 and 24 h. Comparing the treated domestic wastewater quality produced by the two types of septic tanks in terms of physico-chemical and biological characteristics, better results were obtained using the two baffles type.

Degradation and biodegradability improvement of the olive mill wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes.

PubMed

Esfandyari, Yahya; Mahdavi, Yousef; Seyedsalehi, Mahdi; Hoseini, Mohammad; Safari, Gholam Hossein; Ghozikali, Mohammad Ghanbari; Kamani, Hossein; Jaafari, Jalil

2015-04-01

Olive mill wastewater is considered as one of the most polluting effluents of the food industry and constitutes a source of important environmental problems. In this study, the removal of pollutants (chemical oxygen demand (COD), biochemical oxygen demand (BOD5), polyphenols, turbidity, color, total suspended solids (TSS), and oil and grease) from olive oil mill processing wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes was evaluated using a pilot continuous reactor. In the electrochemical unit, aluminum (Al), stainless steel, and RuO2/Ti plates were used. The effects of pH, hydrogen peroxide doses, current density, NaCl concentrations, and reaction times were studied. Under optimal conditions of pH 4, current density of 40 mA/m(2), 1000 mg/L H2O2, 1 g/L NaCl, and 30-min reaction time, the peroxi-electrochemical method yielded very effective removal of organic pollution from the olive mill wastewater diluted four times. The treatment process reduced COD by 96%, BOD5 by 93.6%, total, polyphenols by 94.4%, color by 91.4%, turbidity by 88.7, suspended solids by 97% and oil and grease by 97.1%. The biodegradability index (BOD5/COD) increased from 0.29 to 0.46. Therefore, the peroxi-electrocoagulation/electrooxidation-electroflotation process is considered as an effective and feasible process for pre-treating olive mill wastewater, making possible a post-treatment of the effluent in a biological system.

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.

Long-term effects of the transient COD concentration on the performance of microbial fuel cells.

PubMed

Mateo, S; Gonzalez Del Campo, A; Lobato, J; Rodrigo, M; Cañizares, P; Fernandez-Morales, F J

2016-07-08

In this work, the long-term effects of transient chemical oxygen demands (COD) concentrations over the performance of a microbial fuel cell were studied. From the obtained results, it was observed that the repetitive change in the COD loading rate during 12 h conditioned the behavior of the system during periods of up to 7 days. The main modifications were the enhancement of the COD consumption rate and the exerted current. These enhancements yielded increasing Coulombic efficiencies (CEs) when working with COD concentrations of 300 mg/L, but constant CEs when working with COD concentrations from 900 to 1800 mg/L. This effect could be explained by the higher affinity for the substrate of Geobacter than that of the nonelectrogenic organisms such as Clostridia. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:883-890, 2016. © 2016 American Institute of Chemical Engineers.

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

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.

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater

PubMed Central

Ferraz, Fernanda M.; Bruni, Aline T.; Del Bianchi, Vanildo L.

2009-01-01

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days. PMID:24031316

Improvement of municipal wastewater pretreatment by direct membrane filtration.

PubMed

Nascimento, Thiago A; Mejía, Fanny R; Fdz-Polanco, Fernando; Peña Miranda, Mar

2017-10-01

The high content of particulate matter in municipal wastewater hinders the conventional anaerobic treatments at psychrophilic temperatures. The hydrolysis of the particulate chemical oxygen demand (pCOD) could be the limiting step under these conditions. Therefore, new pretreatments or improved conventional pretreatments are needed in order to separate pCOD. In this work, direct membrane filtration of municipal wastewater, using an ultrafiltration membrane, was investigated. This intensive pretreatment, which aims to separate soluble chemical oxygen demand (sCOD) and to concentrate pCOD, together with anaerobic treatments of both streams at psychrophilic and mesophilic conditions respectively, could be an alternative to the conventional activated sludge process. The obtained results show a removal yield of 24.9% of the total solids (TS) and 45% of total chemical oxygen demand (tCOD), obtaining a permeate free of suspended solids. This physical removal implies the accumulation of solids inside the membrane tank, reaching the values of 45.4 and 4.4 g/L of TS in the sedimentation and filtration sections, respectively. The membrane operated with filtration, backwashing cycles and continuous gas sparging, with a permeate flux predominantly around 10 L/(m 2  h). The results show the viability of the technology to concentrate pCOD and so to improve energy recovery from municipal wastewater.

Aerobic degradation of petroleum refinery wastewater in sequential batch reactor.

PubMed

Thakur, Chandrakant; Srivastava, Vimal C; Mall, Indra D

2014-01-01

The aim of the present work was to study the effect of various parameters affecting the treatment of raw petroleum refinery wastewater (PRW) having chemical oxygen demand (COD) of 350 mg L(-1) and total organic carbon (TOC) of 70 mg L(-1) in sequential batch reactor (SBR). Effect of hydraulic retention time (HRT) was studied in instantaneous fill condition. Maximum COD and TOC removal efficiencies were found to be 80% and 84%, respectively, for fill phase of 2 h and react phase of 2 h with fraction of SBR being filled with raw PRW in each cycle being 0.4. Effect of parameters was studied in terms of settling characteristic of treated slurry. Kinetics of treatment process has been studied. FTIR and UV-visible analysis of PRW before and after treatment have been performed so as to understand the degradation mechanism.

Chemical oxidation of carwash industry wastewater as an effort to decrease water pollution

NASA Astrophysics Data System (ADS)

Bhatti, Zulfiqar Ahmad; Mahmood, Qaisar; Raja, Iftikhar Ahmad; Malik, Amir Haider; Khan, Muhammad Suleman; Wu, Donglei

Car wash wastewater (CWW) contains petroleum, hydrofluoric acid, ammonium bifluoride products, paint residues, rubber, phosphates, oil, grease and volatile organic compounds (VOCs). The present study dealt with various investigations conducted for the treatment of CWW. A treatment system of 5 L capacity was designed in the laboratory. Due to high load of oil and grease, CWW was aerated and scum was removed. Alum was used as coagulant in primary treatment which resulted 93% and 97% reduction in COD and turbidity. During secondary treatment CWW was further treated with waste hydrogen peroxide which resulted in further 71% and 83% reduction in COD and turbidity, respectively. Other desirable changes were also observed in pH, total dissolved solids (TDS), conductivity and dissolved oxygen contents. It was concluded that designed system could be effectively used to treat carwash wastewater that could be reused in the same station.

Leaching of plastic additives to marine organisms.

PubMed

Koelmans, Albert A; Besseling, Ellen; Foekema, Edwin M

2014-04-01

It is often assumed that ingestion of microplastics by aquatic species leads to increased exposure to plastic additives. However, experimental data or model based evidence is lacking. Here we assess the potential of leaching of nonylphenol (NP) and bisphenol A (BPA) in the intestinal tracts of Arenicola marina (lugworm) and Gadus morhua (North Sea cod). We use a biodynamic model that allows calculations of the relative contribution of plastic ingestion to total exposure of aquatic species to chemicals residing in the ingested plastic. Uncertainty in the most crucial parameters is accounted for by probabilistic modeling. Our conservative analysis shows that plastic ingestion by the lugworm yields NP and BPA concentrations that stay below the lower ends of global NP and BPA concentration ranges, and therefore are not likely to constitute a relevant exposure pathway. For cod, plastic ingestion appears to be a negligible pathway for exposure to NP and BPA. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Post-treatment of refinery wastewater effluent using a combination of AOPs (H2O2 photolysis and catalytic wet peroxide oxidation) for possible water reuse. Comparison of low and medium pressure lamp performance.

PubMed

Rueda-Márquez, J J; Levchuk, I; Salcedo, I; Acevedo-Merino, A; Manzano, M A

2016-03-15

The main aim of this work was to study the feasibility of multi-barrier treatment (MBT) consisting of filtration, hydrogen peroxide photolysis (H2O2/UVC) and catalytic wet peroxide oxidation (CWPO) for post-treatment of petroleum refinery effluent. Also the possibility of water reuse or safe discharge was considered. The performance of MBT using medium (MP) and low (LP) pressure lamps was compared as well as operation and maintenance (O&M) cost. Decomposition of organic compounds was followed by means of gas chromatography-mass spectrometry (GC-MS), total organic carbon (TOC) and chemical oxygen demand (COD) analysis. After filtration step (25 μm) turbidity and concentration of suspended solids decreased by 92% and 80%, respectively. During H2O2/UVC process with LP lamp at optimal conditions (H2O2:TOC ratio 8 and UVC dose received by water 5.28 WUVC s cm(-2)) removal of phenolic compounds, TOC and COD was 100%, 52.3% and 84.3%, respectively. Complete elimination of phenolic compounds, 47.6% of TOC and 91% of COD was achieved during H2O2/UVC process with MP lamp at optimal conditions (H2O2:TOC ratio 5, UVC dose received by water 6.57 WUVC s cm(-2)). In order to compare performance of H2O2/UVC treatment with different experimental set up, the UVC dose required for removal of mg L(-1) of COD was suggested as a parameter and successfully applied. The hydrophilicity of H2O2/UVC effluent significantly increased which in turn enhanced the oxidation of organic compounds during CWPO step. After H2O2/UVC treatment with LP and MP lamps residual H2O2 concentration was 160 mg L(-1) and 96.5 mg L(-1), respectively. Remaining H2O2 was fully consumed during subsequent CWPO step (6 and 3.5 min of contact time for LP and MP, respectively). Total TOC and COD removal after MBT was 94.7% and 92.2% (using LP lamp) and 89.6% and 95%, (using MP lamp), respectively. The O&M cost for MBT with LP lamp was estimated to be 0.44 € m(-3) while with MP lamp it was nearly five times higher. Toxicity assessment was performed using two marine species (Vibrio fischeri and Paracentrotus lividus sea-urchin) after each treatment step. The highest toxicity was attributed to H2O2/UVC effluent for both tested species. After MBT a drastic decrease of toxicity was achieved. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Sunlight, iron and radicals to tackle the resistant leftovers of biotreated winery wastewater.

PubMed

Ioannou, Lida; Velegraki, Theodora; Michael, Costas; Mantzavinos, Dionissios; Fatta-Kassinos, Despo

2013-04-01

Winery wastewater is characterized by high organic content consisting of alcohols, acids and recalcitrant high-molecular-weight compounds (e.g. polyphenols, tannins and lignins). So far, biological treatment constitutes the best available technology for such effluents that are characterized by high seasonal variability; however the strict legislation applied on the reclamation and reuse of wastewaters for irrigation purposes introduces the need for further treatment of the bioresistant fraction of winery effluents. In this context, the use of alternative treatment technologies, aiming to mineralize or transform refractory molecules into others which could be further biodegraded, is a matter of great concern. In this study, a winery effluent that had already been treated in a sequencing batch reactor was subjected to further purification by homogeneous and heterogeneous solar Fenton oxidation processes. The effect of various operating variables such as catalyst and oxidant concentration, initial pH, temperature and lamp power on the abatement of chemical oxygen demand (COD), dissolved organic carbon (DOC), color, total phenolics and ecotoxicity has been assessed in the homogeneous solar Fenton process. In addition, a comparative assessment between homogeneous and heterogeneous solar Fenton processes was performed. In the present study the homogeneous solar Fenton process has been demonstrated to be the most effective process, yielding COD, DOC and total phenolics removal of about 69%, 48% and 71% in 120 min of the photocatalytic treatment, respectively.

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.

Harvest Pressure on Coastal Atlantic Cod (Gadus morhua) from Recreational Fishing Relative to Commercial Fishing Assessed from Tag-Recovery Data

PubMed Central

Kleiven, Alf Ring; Fernandez-Chacon, Albert; Nordahl, Jan-Harald; Moland, Even; Espeland, Sigurd Heiberg; Knutsen, Halvor; Olsen, Esben Moland

2016-01-01

Marine recreational fishing is a popular outdoor activity. However, knowledge about the magnitude of recreational catches relative to commercial catches in coastal fisheries is generally sparse. Coastal Atlantic cod (Gadus morhua) is a target species for recreational fishers in the North Atlantic. In Norway, recreational fishers are allowed to use a variety of traps and nets as well as long-line and rod and line when fishing for cod. From 2005 to 2013, 9729 cod (mean size: 40 cm, range: 15–93 cm) were tagged and released in coastal Skagerrak, southeast Norway. Both high-reward (NOK 500) and low-reward tags (NOK 50) were used in this study. Because some harvested fish (even those posting high-reward tags) may go unreported by fishers, reporting rates were estimated from mark-recovery models that incorporate detection parameters in their structure, in addition to survival and mortality estimates. During 2005 to 2013, a total of 1707 tagged cod were recovered and reported by fishers. We estimate the overall annual survival to be 33% (SE 1.5). Recreational rod and line fishing were responsible for 33.7% (SE 2.4) of total mortality, followed by commercial fisheries (15.1% SE 0.8) and recreational fixed gear (6.8% SE 0.4). Natural mortality was 44.4% (SE 2.5) of total mortality. Our findings suggest that recreational fishing—rod and line fishing in particular—is responsible for a substantial part of fishing mortality exerted on coastal cod in southern Norway. PMID:26959371

Harvest Pressure on Coastal Atlantic Cod (Gadus morhua) from Recreational Fishing Relative to Commercial Fishing Assessed from Tag-Recovery Data.

PubMed

Kleiven, Alf Ring; Fernandez-Chacon, Albert; Nordahl, Jan-Harald; Moland, Even; Espeland, Sigurd Heiberg; Knutsen, Halvor; Olsen, Esben Moland

2016-01-01

Marine recreational fishing is a popular outdoor activity. However, knowledge about the magnitude of recreational catches relative to commercial catches in coastal fisheries is generally sparse. Coastal Atlantic cod (Gadus morhua) is a target species for recreational fishers in the North Atlantic. In Norway, recreational fishers are allowed to use a variety of traps and nets as well as long-line and rod and line when fishing for cod. From 2005 to 2013, 9729 cod (mean size: 40 cm, range: 15-93 cm) were tagged and released in coastal Skagerrak, southeast Norway. Both high-reward (NOK 500) and low-reward tags (NOK 50) were used in this study. Because some harvested fish (even those posting high-reward tags) may go unreported by fishers, reporting rates were estimated from mark-recovery models that incorporate detection parameters in their structure, in addition to survival and mortality estimates. During 2005 to 2013, a total of 1707 tagged cod were recovered and reported by fishers. We estimate the overall annual survival to be 33% (SE 1.5). Recreational rod and line fishing were responsible for 33.7% (SE 2.4) of total mortality, followed by commercial fisheries (15.1% SE 0.8) and recreational fixed gear (6.8% SE 0.4). Natural mortality was 44.4% (SE 2.5) of total mortality. Our findings suggest that recreational fishing-rod and line fishing in particular-is responsible for a substantial part of fishing mortality exerted on coastal cod in southern Norway.

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.

pH-adjustment strategy for volatile fatty acid production from high-strength wastewater for biological nutrient removal.

PubMed

Xie, Li; Liu, Hui; Chen, Yin-Guang; Zhou, Qi

2014-01-01

Volatile fatty acid (VFA) production from three types of high-strength organic wastewater (cassava thin stillage, starch wastewater and yellow-wine processing wastewater) were compared. The results showed that cassava thin stillage was the most suitable substrate, based on its high specific VFA production (0.68 g chemical oxygen demand (COD)/g initial soluble chemical oxygen demand (SCOD)) and yield (0.72 g COD/g SCOD) as well as low nutrient content in the substrate and fermented liquid. The acid fermented cassava thin stillage was evaluated and compared with sodium acetate in a sequencing batch reactor system. Total nitrogen removal efficiency was higher with fermented cassava thin stillage than with the sodium acetate. The effects of pH and a pH-adjustment strategy on VFA production and composition were determined using cassava thin stillage. At an initial pH range of 7-11, a relatively high VFA concentration of about 9 g COD/L was obtained. The specific VFA production (g COD/g initial SCOD) increased from 0.27 to 0.47 to 0.67 at pH 8 and from 0.26 to 0.68 to 0.81 at pH 9 (initial pH, interval pH, and constant pH adjustment, respectively). The dominant VFA species changed significantly with the increasing frequency of the pH adjustment. Further studies will examine the metabolic pathways responsible for VFA composition.

beta-Glucan production by Botryosphaeria rhodina on undiluted olive-mill wastewaters.

PubMed

Crognale, S; Federici, F; Petruccioli, M

2003-12-01

Botryosphaeria rhodina produced beta-glucan when grown on undiluted olive-mill wastewaters (OMW). The production of exopolysaccharide increased with the COD up to 17.2 g l(-1) on the most loaded OMW (151 and 66 g l(-1) of COD and total sugar, respectively). The total phenol content of OMW was reduced from 8 to 4.1 g l(-1).

Exophiala angulospora causes systemic inflammation in atlantic cod Gadus morhua.

PubMed

Gjessing, Mona Cecilie; Davey, Marie; Kvellestad, Agnar; Vrålstad, Trude

2011-10-06

Species of Exophiala are opportunistic fungal pathogens that may infect a broad range of warm- and cold-blooded animals, including salmonids and Atlantic cod. In the present study, we observed abnormal swimming behaviour and skin pigmentation and increased mortality in cod kept in an indoor tank. Necropsy revealed foci of different sizes with a greyish to brownish colour in internal organs of diseased fish. The foci consisted of ramifying darkly pigmented fungal hyphae surrounded by distinct layers of inflammatory cells, including macrophage-like cells. In the inner layer with many hyphae, the macrophage-like cells were dead. We observed no apparent restriction of fungal growth by the inflammatory response. A darkly pigmented fungus was repeatedly isolated in pure culture from foci of diseased fish and identified as Exophiala angulospora using morphological and molecular characters. This species has not been previously reported to cause disease in cod, but has been reported as an opportunistic pathogen of both marine and freshwater fish. Based on the morphology and sequence analysis presented here, we conclude that E. angulospora caused the observed chronic multifocal inflammation in internal organs of cod, leading to severe disease and mortality.

Optimization of an integrated sponge--granular activated carbon fluidized bed bioreactor as pretreatment to microfiltration in wastewater reuse.

PubMed

Xing, W; Ngo, H H; Guo, W S; Listowski, A; Cullum, P

2012-06-01

A specific integrated fluidized bed bioreactor (iFBBR) was optimized in terms of organic loading rate (OLR), hydraulic retention time (HRT) and frequency of new sustainable flocculant (NSBF) addition for primary treated sewage effluent (PTSE) treatment. It was observed that iFBBR achieved the best performance with the operating conditions of 4 times/day NSBF addition, HRT of 90 min and OLR of 8.64 kg COD/day m(3). The removal efficiencies were found to be more than 93% of dissolved organic carbon (DOC), 61% of total nitrogen (T-N) and 60% of total phosphorus (T-P). iFBBR as pretreatment of submerged microfiltration (SMF) is successful in increasing the critical flux and reducing the membrane fouling. NSBF-iFBBR-SMF hybrid system led to very high organic removal efficiency with an average DOC removal of 97% from synthetic PTSE. Copyright © 2012 Elsevier Ltd. All rights reserved.

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).

Peroxone mineralization of chemical oxygen demand for direct potable water reuse: Kinetics and process control.

PubMed

Wu, Tingting; Englehardt, James D

2015-04-15

Mineralization of organics in secondary effluent by the peroxone process was studied at a direct potable water reuse research treatment system serving an occupied four-bedroom, four bath university residence hall apartment. Organic concentrations were measured as chemical oxygen demand (COD) and kinetic runs were monitored at varying O3/H2O2 dosages and ratios. COD degradation could be accurately described as the parallel pseudo-1st order decay of rapidly and slowly-oxidizable fractions, and effluent COD was reduced to below the detection limit (<0.7 mg/L). At dosages ≥4.6 mg L(-1) h(-1), an O3/H2O2 mass ratio of 3.4-3.8, and initial COD <20 mg/L, a simple first order decay was indicated for both single-passed treated wastewater and recycled mineral water, and a relationship is proposed and demonstrated to estimate the pseudo-first order rate constant for design purposes. At this O3/H2O2 mass ratio, ORP and dissolved ozone were found to be useful process control indicators for monitoring COD mineralization in secondary effluent. Moreover, an average second order rate constant for OH oxidation of secondary effluent organics (measured as MCOD) was found to be 1.24 × 10(7) ± 0.64 × 10(7) M(-1) S(-1). The electric energy demand of the peroxone process is estimated at 1.73-2.49 kW h electric energy for removal of one log COD in 1 m(3) secondary effluent, comparable to the energy required for desalination of medium strength seawater. Advantages/disadvantages of the two processes for municipal wastewater reuse are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Uncertainties in stormwater runoff data collection from a small urban catchment, Southeast China.

PubMed

Huang, Jinliang; Tu, Zhenshun; Du, Pengfei; Lin, Jie; Li, Qingsheng

2010-01-01

Monitoring data are often used to identify stormwater runoff characteristics and in stormwater runoff modelling without consideration of their inherent uncertainties. Integrated with discrete sample analysis and error propagation analysis, this study attempted to quantify the uncertainties of discrete chemical oxygen demand (COD), total suspended solids (TSS) concentration, stormwater flowrate, stormwater event volumes, COD event mean concentration (EMC), and COD event loads in terms of flow measurement, sample collection, storage and laboratory analysis. The results showed that the uncertainties due to sample collection, storage and laboratory analysis of COD from stormwater runoff are 13.99%, 19.48% and 12.28%. Meanwhile, flow measurement uncertainty was 12.82%, and the sample collection uncertainty of TSS from stormwater runoff was 31.63%. Based on the law of propagation of uncertainties, the uncertainties regarding event flow volume, COD EMC and COD event loads were quantified as 7.03%, 10.26% and 18.47%.

Performance and stability of an expanded granular sludge bed reactor modified with zeolite addition subjected to step increases of organic loading rate (OLR) and to organic shock load (OSL).

PubMed

Pérez-Pérez, T; Pereda-Reyes, I; Pozzi, E; Oliva-Merencio, D; Zaiat, M

2018-01-01

This paper shows the effect of organic shock loads (OSLs) on the anaerobic digestion (AD) of synthetic swine wastewater using an expanded granular sludge bed (EGSB) reactor modified with zeolite. Two reactors (R1 and R2), each with an effective volume of 3.04 L, were operated for 180 days at a controlled temperature of 30 °C and hydraulic retention time of 12 h. In the case of R2, 120 g of zeolite was added. The reactors were operated with an up-flow velocity of 6 m/h. The evolution of pH, total Kjeldahl nitrogen, chemical oxygen demand (COD) and volatile fatty acids (VFAs) was monitored during the AD process with OSL and increases in the organic loading rate (OLR). In addition, the microbial composition and changes in the structure of the bacterial and archaeal communities were assessed. The principal results demonstrate that the presence of zeolite in an EGSB reactor provides a more stable process at higher OLRs and after applying OSL, based on both COD and VFA accumulation, which presented with significant differences compared to the control. Denaturing gradient gel electrophoresis band profiles indicated differences in the populations of Bacteria and Archaea between the R1 and R2 reactors, attributed to the presence of zeolite.

Nitrification denitrification enhanced biological phosphorous removal (NDEBPR) occurs in a lab-scale alternating hypoxic/oxic membrane bioreactor.

PubMed

Sibag, Mark; Kim, Han-Seung

2012-01-01

Strict anaerobic or anoxic maintenance of the system and process susceptibility to low organic loading are major concerns in nitrification denitrification enhanced biological phosphorous removal (NDEBPR). The study has initiated NDEBPR in a lab-scale alternating hypoxic/oxic membrane bioreactor by developing an enhanced mixed microbial culture capable of removing 97±2% COD, 99±0.84% NH(3)-N, 90±3% TN, and 96±1% TP-PO(4)(3-) with 20-day SRT. The viable cells ranging from 1.6×10(8) to 2.0×10(8)cells/ml estimated from the total bacterial genomic DNA (6.43-7.83 μg DNA/ml) represented only 5% of the MLVSS indicating low microbial biomass concentration. Reducing the organic load from 1250 to 750 mg COD/ml as glucose did not deteriorate the effluent quality (3.77±1.0 mg N-TN/l; 0.08±0.24 mg NH(3)-N/l; and 0.32±0.10 mg PO(4)(3-)-P/l). These observations are characteristics of activated sludge that harbors denitrifying polyphosphate accumulating organisms (DPAOs). The results showed that NDEBPR can be achieved under alternating hypoxic/oxic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Crystallography Open Database – an open-access collection of crystal structures

PubMed Central

Gražulis, Saulius; Chateigner, Daniel; Downs, Robert T.; Yokochi, A. F. T.; Quirós, Miguel; Lutterotti, Luca; Manakova, Elena; Butkus, Justas; Moeck, Peter; Le Bail, Armel

2009-01-01

The Crystallography Open Database (COD), which is a project that aims to gather all available inorganic, metal–organic and small organic molecule structural data in one database, is described. The database adopts an open-access model. The COD currently contains ∼80 000 entries in crystallographic information file format, with nearly full coverage of the International Union of Crystallography publications, and is growing in size and quality. PMID:22477773

77 FR 13510 - Pacific Cod by Catcher Vessels Less Than 50 Feet (15.2 Meters) Length Overall Using Hook-and-Line...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-07

.... 101126522-0640-2] RIN 0648-XB062 Pacific Cod by Catcher Vessels Less Than 50 Feet (15.2 Meters) Length... (CVs) less than 50 feet (15.2 meters (m)) in length overall (LOA) using hook-and-line gear in the... season allowance of the 2012 Pacific cod total allowable catch apportioned to CVs less than 50 feet (15.2...

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.

Effect of sparging rate on permeate quality in a submerged anaerobic membrane bioreactor (SAMBR) treating leachate from the organic fraction of municipal solid waste (OFMSW).

PubMed

Trzcinski, Antoine P; Stuckey, David C

2016-03-01

This paper focuses on the treatment of leachate from the organic fraction of municipal solid waste (OFMSW) in a submerged anaerobic membrane bioreactor (SAMBR). Operation of the SAMBR for this type of high strength wastewater was shown to be feasible at 5 days hydraulic retention time (HRT), 10 L min(-1) (LPM) biogas sparging rate and membrane fluxes in the range of 3-7 L m(-2) hr(-1) (LMH). Under these conditions, more than 90% COD removal was achieved during 4 months of operation without chemical cleaning the membrane. When the sparging rate was reduced to 2 LPM, the transmembrane pressure increased dramatically and the bulk soluble COD concentration increased due to a thicker fouling layer, while permeate soluble COD remained constant. Permeate soluble COD concentration increased by 20% when the sparging rate increased to 10 LPM. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

A super high-rate sulfidogenic system for saline sewage treatment.

PubMed

Tsui, To-Hung; Chen, Lin; Hao, Tianwei; Chen, Guang-Hao

2016-11-01

This study proposes a novel approach to resolve the challenging issue of sludge bed clogging in a granular sulfate-reducing upflow sludge bed (GSRUSB) reactor by means of introducing intermittent gas sparging to advance it into a super high-rate anaerobic bioreactor. Over a 196-day lab-scale trial, the GSRUSB system was operated from nominal hydraulic retention time of 4-hr to 40-min and achieved the highest organic loading rate of 13.31 kg COD/m 3 ·day which is substantially greater than the typical loading of 2.0-3.5 kg COD/m 3 ·day in a conventional upflow anaerobic sludge bed reactor treating dilute organic strength wastewater. The average organic removal efficiency and total dissolved sulfide of this system were 90 ± 4.2% and 158 ± 28 mg S/L, while organics residual in the effluent was 34 ± 14 mg COD/L. The control stage (without gas sparging) revealed that the sludge bed clogging happened concomitantly with the significant drop in extracellular polymeric substance content of granular sludge, through relevant chemical measurements and confocal laser scanning microscopy analyses. On the other hand, compared with increasing the effluent recirculation ratio (from 1.4 to 5), the three-dimensional computational fluid dynamics modeling in combination with energy dissipation analysis demonstrated that the gas sparging (at a superficial gas velocity of 0.8 m s -1 ) can create a 23 times higher liquid shear as well as enhanced particle attrition. Overall, this study not only developed a super high-rate anaerobic bioreactor for saline sewage treatment, but also shed light on the role of intermittent gas sparging in control of sludge bed clogging for anaerobic bioreactors. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Use of macroalgae for the evaluation of organic pollution in the Preto river, northwest of São Paulo State].

PubMed

Necchi Júnior, O; Branco, H Z; Dip, M R

1994-01-01

The Preto River, located in the northwest of São Paulo State, receives a total wastewater load of 15.150 kg DBO day-1, from which 13.685 kg DBO day-1 (90.5%) corresponds to domestic sewage, and the city of São José do Rio Preto contributes with 12.400 kg DBO day-1 (90% of domestic sewage). During the period from August 1990 through January 1991, monthly sampling was carried out to evaluate the use of macroalgae as bioindicator of organic pollution. Five sampling sites were established along the main river and the following variables were analised: temperature, conductance, turbidity, dissolved oxygen, BOD, COD, total and fecal coliforms, and composition and abundance of macroalgal communities. Data were submitted to analysis of variance, correlation coefficient, cluster analysis (four different approaches) and converted to biological indices (species deficit, relative pollution, saprobity, diversity and uniformity indices). A wide range in water quality was found (particularly for conductance, oxygen, BOD and COD) among the sampling sites, which were classified into three groups (polluted, moderately polluted and unpolluted/weakly polluted). As regards the occurrence and abundance of macroalgae the Rhodophyta were found only in unpolluted or weakly polluted sites, whereas Cyanophyta occurred mostly under high pollution load; the Chlorophyta species were observed under a wide range of conditions. Among the biological indices, saprobity was the most sensitive and correlated to all water variables and the other indices. Cluster analyses showed that the composition of macroalgal communities was consistent with the levels of organic pollution in the Preto River.

Use of extant kinetic parameters to predict effluent concentrations of specific organic compounds at full-scale facilities.

PubMed

Ellis, Timothy G; Eliosov, Boris

2004-01-01

To use the results of kinetic tests to predict effluent concentrations of specific contaminants in activated sludge systems, the fraction of the biomass that has an ability to degrade the test compound (i.e., competent biomass) must be estimated. A calibration procedure was developed to assess the competent biomass concentration because the chemical oxygen demand (COD) fraction tended to underestimate the degrading fraction for three of the four test compounds. Acetone, for instance, had a measured influent COD fraction of 0.08%, and the actual competent fraction was estimated to be 2.3%, based on the model calibration. Once the competent biomass fraction in the mixed liquor was determined, the extant kinetic parameters were subsequently used to predict activated sludge system performance. Predicted effluent concentrations were within 2, 5, and 16% of the average measured concentrations for acetone, linear alkylbenzene sulfonate, and furfural, respectively. Day-to-day predictions for these compounds were less accurate, possibly because of the non-steady-state nature of the activated sludge systems studied. The difference between the fraction of the influent COD contributed by the target compounds and the competent biomass fraction in the mixed liquor was found to be more significant when the target compound contributed less than 1% of the influent organic matter. The chemical structure of the target compound and chemical composition of the influent likely had an effect on the resulting competent biomass concentration. The total maximum growth rate, microX, was observed to be independent of the influent concentration of acetone and furfural, thus suggesting that the competent biomass concentration for these compounds was not affected by the changes in their influent concentrations. Consequently, a majority of competent biomass growth resulted from the degradation of other substrates, resulting in a competent biomass concentration significantly higher than predicted based on the influent COD fraction contributed by the test compound.

Catalytic ozonation-biological coupled processes for the treatment of industrial wastewater containing refractory chlorinated nitroaromatic compounds*

PubMed Central

Li, Bing-zhi; Xu, Xiang-yang; Zhu, Liang

2010-01-01

A treatability study of industrial wastewater containing chlorinated nitroaromatic compounds (CNACs) by a catalytic ozonation process (COP) with a modified Mn/Co ceramic catalyst and an aerobic sequencing batch reactor (SBR) was investigated. A preliminary attempt to treat the diluted wastewater with a single SBR resulted in ineffective removal of the color, ammonia, total organic carbon (TOC) and chemical oxygen demand (COD). Next, COP was applied as a pretreatment in order to obtain a bio-compatible wastewater for SBR treatment in a second step. The effectiveness of the COP pretreatment was assessed by evaluating wastewater biodegradability enhancement (the ratio of biology oxygen demand after 5 d (BOD5) to COD), as well as monitoring the evolution of TOC, carbon oxidation state (COS), average oxidation state (AOS), color, and major pollutant concentrations with reaction time. In the COP, the catalyst preserved its catalytic properties even after 70 reuse cycles, exhibiting good durability and stability. The performance of SBR to treat COP effluent was also examined. At an organic loading rate of 2.0 kg COD/(m3·d), with hydraulic retention time (HRT)=10 h and temperature (30±2) °C, the average removal efficiencies of NH3-N, COD, BOD5, TOC, and color in a coupled COP/SBR process were about 80%, 95.8%, 93.8%, 97.6% and 99.3%, respectively, with average effluent concentrations of 10 mg/L, 128 mg/L, 27.5 mg/L, 25.0 mg/L, and 20 multiples, respectively, which were all consistent with the national standards for secondary discharge of industrial wastewater into a public sewerage system (GB 8978-1996). The results indicated that the coupling of COP with a biological process was proved to be a technically and economically effective method for treating industrial wastewater containing recalcitrant CNACs. PMID:20205304

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.

Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

PubMed

Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

2015-05-15

Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total dissolved polyphenols content of 0.35 mg caffeic acid equivalent L(-1) was found. Respirometry tests revealed low biodegradability enhancement along the SPEF process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Who’s your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod

PubMed Central

Unmack, Peter J.; Dyer, Fiona J.; Lintermans, Mark

2016-01-01

Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod, Maccullochella peelii and Trout Cod, Maccullochella macquariensis which were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod–Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs. PMID:27812407

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.

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.

Integrated chemical treatment of municipal wastewater using waste hydrogen peroxide and ultraviolet light

NASA Astrophysics Data System (ADS)

Bhatti, Zulfiqar Ahmed; Mahmood, Qaisar; Raja, Iftikhar Ahmad; Malik, Amir Haider; Rashid, Naim; Wu, Donglei

Dilemmas like water shortage, rapid industrialization, growing human population and related issues have seriously affected human health and environmental sustainability. For conservation and sustainable use of our water resources, innovative methods for wastewater treatment are continuously being explored. Advance Oxidation Processes (AOPs) show a promising approach to meet specific objectives of municipal wastewater treatment (MWW). The MWW samples were pretreated with Al 2(SO 4) 4·8H 2O (Alum) at different doses 4, 8, 12-50 mg/L to enhance the sedimentation. The maximum COD removal was observed at alum treatments in range of 28-32 mg/L without increasing total dissolved solids (TDS). TDS were found to increase when the alum dose was increased from 32-40 mg/L. In the present study, the optimum alum dose of 30 mg/L for 3 h of sedimentation and subsequent integrated H 2O 2/UV treatment was applied (using 2.5 mL/L of 40% waste H 2O 2 and 35% fresh H 2O 2 separately). Organic and inorganic pollutants, contributing towards chemical oxygen demand (COD), biological oxygen demand (BOD), turbidity and total dissolved solids were degraded by H 2O 2/UV. About 93% COD, 90% BOD and 83% turbidity reduction occurred when 40% waste H 2O 2 was used. When using fresh H 2O 2, 63% COD, 68% BOD and 86% turbidity reduction was detected. Complete disinfection of coliform bacteria occurred by using 40% H 2O 2/UV. The most interesting part of this research was to compare the effectiveness of waste H 2O 2 with fresh H 2O 2. Waste H 2O 2 generated from an industrial process of disinfection was found more effective in the treatment of MWW than fresh 35% H 2O 2.

Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae — can we identify the underlying factors?

PubMed Central

van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F.; Kjørsvik, Elin; Hamre, Kristin

2015-01-01

The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks. PMID:26038712

Catalytic ozonation of organic pollutants from bio-treated dyeing and finishing wastewater using recycled waste iron shavings as a catalyst: Removal and pathways.

PubMed

Wu, Jin; Ma, Luming; Chen, Yunlu; Cheng, Yunqin; Liu, Yan; Zha, Xiaosong

2016-04-01

Catalytic ozonation of organic pollutants from actual bio-treated dyeing and finishing wastewater (BDFW) with iron shavings was investigated. Catalytic ozonation effectively removed organic pollutants at initial pH values of 7.18-7.52, and the chemical oxygen demand (COD) level decreased from 142 to 70 mg·L(-1) with a discharge limitation of 80 mg·L(-1). A total of 100% and 42% of the proteins and polysaccharides, respectively, were removed with a decrease in their contribution to the soluble COD from 76% to 41%. Among the 218 organic species detected by liquid chromatography-mass spectrometry, 58, 77, 79 and 4 species were completely removed, partially removed, increased and newly generated, respectively. Species including textile auxiliaries and dye intermediates were detected by gas chromatography-mass spectrometry. The inhibitory effect decreased from 51% to 33%, suggesting a reduction in the acute toxicity. The enhanced effect was due to hydroxyl radical (OH) oxidation, co-precipitation and oxidation by other oxidants. The proteins were removed by OH oxidation (6%), by direct ozonation, co-precipitation and oxidation by other oxidants (94%). The corresponding values for polysaccharides were 21% and 21%, respectively. In addition, the iron shavings behaved well in successive runs. These results indicated that the process was favorable for engineering applications for removal of organic pollutants from BDFW. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

High solids co-digestion of food and landscape waste and the potential for ammonia toxicity

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

Drennan, Margaret F.; DiStefano, Thomas D., E-mail: thomas.distefano@bucknell.edu

Highlights: • We evaluated co-digestion of food and landscape waste with a pilot-scale anaerobic dry digester. • We evaluated reactor performance at 35 °C under low and high organic loading rates. • Performance was stable under low organic loading rate, but declined under high organic loading rate. • Respirometry was employed to investigate potential inhibition due to ammonia. • Landscape waste was unsuitable in increasing the C:N ratio during codigestion. - Abstract: A pilot-scale study was completed to determine the feasibility of high-solids anaerobic digestion (HSAD) of a mixture of food and landscape wastes at a university in central Pennsylvaniamore » (USA). HSAD was stable at low loadings (2 g COD/L-day), but developed inhibitory ammonia concentrations at high loadings (15 g COD/L-day). At low loadings, methane yields were 232 L CH{sub 4}/kg COD fed and 229 L CH{sub 4}/kg VS fed, and at high loadings yields were 211 L CH{sub 4}/kg COD fed and 272 L CH{sub 4}/kg VS fed. Based on characterization and biodegradability studies, food waste appears to be a good candidate for HSAD at low organic loading rates; however, the development of ammonia inhibition at high loading rates suggests that the C:N ratio is too low for use as a single substrate. The relatively low biodegradability of landscape waste as reported herein made it an unsuitable substrate to increase the C:N ratio. Codigestion of food waste with a substrate high in bioavailable carbon is recommended to increase the C:N ratio sufficiently to allow HSAD at loading rates of 15 g COD/L-day.« less

Effect of non-feeding period length on the intermittent operation of UASB reactors treating dairy effluents.

PubMed

Coelho, N M; Rodrigues, A A; Arroja, L M; Capela, I F

2007-02-01

Recent environmental concerns have prompted a re-evaluation of conventional management strategies and refueled the search of innovative waste management practices. In this sense, the anaerobic digestion of both fat and the remaining complex organic matter present in dairy wastewaters is attractive, although the continuous operation of high rate anaerobic processes treating this type of wastewaters causes the failure of the process. This work accesses the influence of non-feeding period length on the intermittent operation of mesophilic UASB reactors treating dairy wastewater, in order to allow the biological degradation to catch up with adsorption phenomenon. During the experiments, two UASB reactors were subject to three organic loading rates, ranging from 6 to 12 g(COD) x L(-1) x d(-1), with the same daily load applied to both reactors, each one with a different non-feeding period. Both reactors showed good COD removal efficiencies (87-92%). A material balance for COD in the reactors during the feeding and non-feeding periods showed the importance of the feedless period, which allowed the biomass to degrade substrate that was accumulated during the feeding period. The reactor with the longest non-feeding period had a better performance, which resulted in a higher methane production and adsorption capacity for the same organic load applied with a consequent less accumulation of substrate into the biomass. In addition, both reactors had a stable operation for the organic load of 12 g(COD) x L(-1) x d(-1), which is higher than the maximum applicable load reported in literature for continuous systems (3-6 g(COD) x L(-1) x d(-1)). (c) 2006 Wiley Periodicals, Inc.

Treatment of low-strength soluble wastewater using an anaerobic baffled reactor (ABR).

PubMed

Gopala Krishna, G V T; Kumar, Pramod; Kumar, Pradeep

2009-01-01

Treatment of low-strength soluble wastewater (COD approximately 500 mg/L) was studied using an eight chambered anaerobic baffled reactor (ABR). At pseudo steady-state (PSS), the average total and soluble COD values (COD(T) and COD(S)) at 8h hydraulic retention time (HRT) were found to be around 50 and 40 mg/L, respectively, while at 10h HRT average COD(T) and COD(S) values were of the order of 47 and 37 mg/L, respectively. COD and BOD (3 day, 27 degrees C) removal averaged more than 90%. Effluent conformed to Indian standards laid down for BOD (less than 30 mg/L). Reactor effluent characteristics exhibited very low values of standard deviation indicating excellent reactor stability at PSS in terms of effluent characteristics. Based on mass balance calculations, more than 60% of raw wastewater COD was estimated to be recovered as CH(4) in the gas phase. Compartment-wise profiles indicated that most of the BOD and COD got reduced in the initial compartments only. Sudden drop in pH (7.8-6.7) and formation of volatile fatty acids (VFA) (53-85 mg/L) were observed in the first compartment due to acidogenesis and acetogenesis. The pH increased and VFA concentration decreased longitudinally down the reactor. Residence time distribution (RTD) studies revealed that the flow pattern in the ABR was neither completely plug-flow nor perfectly mixed. Observations from scanning electron micrographs (SEM) suggest that distinct phase separation takes place in an ABR.

Application of the International Water Association activated sludge models to describe aerobic sludge digestion.

PubMed

Ghorbani, M; Eskicioglu, C

2011-12-01

Batch and semi-continuous flow aerobic digesters were used to stabilize thickened waste-activated sludge at different initial conditions and mean solids retention times. Under dynamic conditions, total suspended solids, volatile suspended solids (VSS) and total and particulate chemical oxygen demand (COD and PCOD) were monitored in the batch reactors and effluent from the semi-continuous flow reactors. Activated Sludge Model (ASM) no. 1 and ASM no. 3 were applied to measured data (calibration data set) to evaluate the consistency and performances of models at different flow regimes for digester COD and VSS modelling. The results indicated that both ASM1 and ASM3 predicted digester COD, VSS and PCOD concentrations well (R2, Ra2 > or = 0.93). Parameter estimation concluded that compared to ASM1, ASM3 parameters were more consistent across different batch and semi-continuous flow runs with different operating conditions. Model validation on a data set independent from the calibration data successfully predicted digester COD (R2 = 0.88) and VSS (R2 = 0.94) concentrations by ASM3, while ASM1 overestimated both reactor COD (R2 = 0.74) and VSS concentrations (R2 = 0.79) after 15 days of aerobic batch digestion.

The acute phase response of cod (Gadus morhua L.): expression of immune response genes.

PubMed

Audunsdottir, Sigridur S; Magnadottir, Bergljot; Gisladottir, Berglind; Jonsson, Zophonias O; Bragason, Birkir Th

2012-02-01

An acute phase response (APR) was experimentally induced in Atlantic cod (Gadus morhua L.) by intramuscular injection of turpentine oil. The change in the expression of immune related genes was monitored in the anterior kidney and the spleen over a period of 7 days. The genes examined were two types of pentraxins, apolipoprotein A1 (ApoA-I), the complement component C3, interleukin-1β (IL-1β), transferrin, cathelicidin, and hepcidin. All genes were constitutively expressed in both organs and their expression amplified by the turpentine injection. A pattern of response was observed both with respect to the organ preference and to the timing of a maximum response. The increased gene expression of the pentraxins, ApoA-I and C3 was restricted to the anterior kidney, the gene expression of IL-1β, cathelicidin, and transferrin increased in both organs, while hepcidin gene expression was only significantly increased in the spleen. The pentraxins and ApoA-I appear to be early mediators of APR in cod, possibly stimulating C3 and IL-1β response, while the antimicrobial peptides may play a minor role. The increase in transferrin gene expression in both organs, and apparent indifference to cortisol release associated with the turpentine injection, suggests that this could be a typical acute phase protein in cod. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

A Novel Thermal Sensor for the Sensitive Measurement of Chemical Oxygen Demand

PubMed Central

Yao, Na; Liu, Zhuan; Chen, Ying; Zhou, Yikai; Xie, Bin

2015-01-01

A novel rapid methodology for determining the chemical oxygen demand (COD) based on a thermal sensor with a flow injection analysis system was proposed and experimentally validated. The ability of this sensor to detect and monitor COD was based on the degree of enthalpy increase when sodium hypochlorite reacted with the organic content in water samples. The measurement results were correlated with COD and were compared against the conventional method using potassium dichromate. The assay required only 5–7 min rather than the 2 h required for evaluation by potassium dichromate. The linear range was 5–1000 mg/L COD, and the limit of detection was very low, 0.74 mg/L COD. Moreover, this method exhibited high tolerance to chloride ions; 0.015 mol/L chloride ions had no influence on the response. Finally, the sensor was used to detect the COD of different water samples; the results were verified by the standard dichromate method. PMID:26295397

Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

PubMed

Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

2016-11-01

The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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.

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.

Evaluation of Ficus benjamina wood chip-based fungal biofiltration for the treatment of Tequila vinasses.

PubMed

Marco Antonio, Garzón-Zúñiga; Angélica Julieta, Alvillo-Rivera; Esperanza, Ramírez Camperos; Gerardo, Buelna; Gerardo, Díaz-Godínez; Edson Baltazar, Estrada-Arriaga

2018-03-01

This study was focused on the application of an aerobic biofiltration (BF) with Ficus benjamina wood chips as support medium, inoculated with two basidiomycete fungi, Phanerochaete chrysosporium (BF 1) and Trametes versicolor (BF 2), to treat Tequila vinasses from a Tequila industry. The biofiltration system was compared with a biofilter system without basidiomycete fungi (BF W), in order to determine the influence of fungi on the treatment of vinasses. Three different vinasses/water ratios (30/70, 40/60, and 50/50) were evaluated. The maximum removals of chemical oxygen demand (COD) obtained during each operation step were 72% (BF 1), 72% (BF 2), and 8% (BF W) for 30 vinasses/70 water; 72% (BF 1), 73% (BF 2), and 66% (BF W) for 40 vinasses/60 water; and 22% (BF 1), 20% (BF 2), and 18% (BF W) for 50 vinasses/50 water. The total organic carbon (TOC) removal was significantly increased using a volumetric organic load of 5.5 kg COD m -3 d -1 . During the operation of the biofilters, the enzymatic activity of laccase was present, even at the step of highest concentration of vinasses.

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.

Distribution and diet of larval and juvenile Arctic cod ( Boreogadus saida) in the shallow Canadian Beaufort Sea

NASA Astrophysics Data System (ADS)

Walkusz, Wojciech; Paulic, Joclyn E.; Williams, William J.; Kwasniewski, Slawomir; Papst, Michael H.

2011-02-01

The distribution and diet of larval and juvenile Arctic cod ( Boreogadus saida) were studied during summer 2005 in the coastal Canadian Beaufort Sea. A total of 275 individuals were captured and the highest abundance was observed at station depths of 20-30 m. This corresponds well with the location of the frontal zone where the Mackenzie River plume water and open sea water meet. Diet examinations were performed on 220 Arctic cod, which were found undamaged from sampling. We observed a gradual decrease in prey number per fish and increase in prey size as larvae grew which corresponded to a shift from Rotifera and nauplii towards larger copepodid stages. However, at all sizes, the larvae remain generalists and feed on a broad range of organisms. Environmental changes due to climate warming could have a two-fold impact on fish larvae feeding in the studied region. First, the potential for increased primary production may lead to increased zooplankton production that may impact the feeding and nutrition positively. On the other hand, greater discharge of turbid water from the Mackenzie River may reduce light penetration in the water column that may negatively influence the ability of visual predators to successively forage.

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.

Start-up of a pilot-scale anaerobic fixed film reactor at low temperature treating slaughterhouse wastewater.

PubMed

del Pozo, R; Diez, V; Salazar, G

2002-01-01

A pilot-scale anaerobic fixed film reactor (AFFR) with vertically arranged PVC tubes as biomass carrier, treating poultry slaughterhouse wastewater was started-up in 74 days at temperatures between 20-24 degrees C. The start-up process consisted of a long acclimatization phase followed by a low loaded growth phase, a gradual increase of OLR upto 9.2 kg COD/m3d, and a final maturation phase at moderated loads of 2.7 kg COD/m3d at which total COD removal efficiencies of 57% were achieved. Alkalinity ratio IA:PA was found to be the best control parameter to avoid VFA accumulation. OLR increase based on pH control was not satisfactory because changes in CO2 solubility caused daily by temperature and flow variations led to pH oscillations of 0.2 units. The low wastewater alkalinity, 260 mg/l CaCO3 was insufficient to buffer the pH system, therefore the pH decrease associated with the VFA accumulation was not easily detected and could not be used as a way of OLR control. Organic matter removal took place by accumulation and biodegradation processes. Limitation in the reactor hydrodynamics and particulate fraction hydrolysis was detected at high flow rates.

Biogas-pH automation control strategy for optimizing organic loading rate of anaerobic membrane bioreactor treating high COD wastewater.

PubMed

Yu, Dawei; Liu, Jibao; Sui, Qianwen; Wei, Yuansong

2016-03-01

Control of organic loading rate (OLR) is essential for anaerobic digestion treating high COD wastewater, which would cause operation failure by overload or less efficiency by underload. A novel biogas-pH automation control strategy using the combined gas-liquor phase monitoring was developed for an anaerobic membrane bioreactor (AnMBR) treating high COD (27.53 g·L(-1)) starch wastewater. The biogas-pH strategy was proceeded with threshold between biogas production rate >98 Nml·h(-1) preventing overload and pH>7.4 preventing underload, which were determined by methane production kinetics and pH titration of methanogenesis slurry, respectively. The OLR and the effluent COD were doubled as 11.81 kgCOD·kgVSS(-1)·d(-1) and halved as 253.4 mg·L(-1), respectively, comparing with a constant OLR control strategy. Meanwhile COD removal rate, biogas yield and methane concentration were synchronously improved to 99.1%, 312 Nml·gCODin(-1) and 74%, respectively. Using the biogas-pH strategy, AnMBR formed a "pH self-regulation ternary buffer system" which seizes carbon dioxide and hence provides sufficient buffering capacity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of combined membrane biological reactor and electro-oxidation processes for the treatment of landfill leachates.

PubMed

Aloui, Fathi; Fki, Firas; Loukil, Slim; Sayadi, Sami

2009-01-01

Landfill leachate (LFL) is a very complex wastewater that poses considerable hazards to local communities and the environment. With this concern in mind, the present study was undertaken to investigate the performance of an aerobic membrane bioreactor treating raw LFL from Djebel Chekir (Tunisia) discharge. The LFL samples collected from this site were found to be highly loaded with organic matter, ammonia, salts, greases, phenols and hydrocarbons. Important removals of chemical oxygen demand (COD) and NH4+-N were attained after 44 days of treatment at optimum conditions for the membrane and with organic loading rates (OLR) of 1.9 and 2.7 grams COD per litter and day. This treatment allowed for an important detoxification of the landfill leachates and a significant elimination of the microorganisms. Electrochemical oxidation using Pi/Ti was applied as a post-treatment and after the biological process in order to reduce the residual ammonia and COD. At a pH value of 9, current density of 4 A dm(-2) and electrolysis time of 60 minutes, COD and ammonia nitrogen were reduced to 1,000 mg L(-1) and 27 mg L(-1), respectively. COD and NH4+-N removals were accompanied by significant detoxification.

Fort Dix Remedial Investigation/Feasibility Study for 13 Sites, Final Technical Plan, Data Item A004

DTIC Science & Technology

1995-09-01

39 oxygen demand (COD), TSS, total dissolved solids ( TDS ), nitrate/nitrite, sulfate, W0109314.M80 7133-04 5-4 SECTION 5 phosphateand alkalinity...TSS, TDS , BOD-5, COD, alkalinity, hardness, 38 and gross alpha, beta, and gamma radiation (Table 2). 39 W0109314.M80 12-2 7133-°4 SECTION 12 l...wells. Groundwater samples 28 will be analyzed for TCL VOCs, TCL SVOCs, TAL metals (nonfiltered and filtered) 29 TSS, TDS , BOD-5, COD, alkalinity

Polishing of POME by Chlorella sp. in suspended and immobilized system

NASA Astrophysics Data System (ADS)

Lahin, F. A.; Sarbatly, R.; Suali, E.

2016-06-01

The effect of using suspended and immobilized growth of Chlorella sp. to treat POME was studied. Cotton and nylon ropes were used as the immobilization material in a rotating microalgae biofilm reactor. The result showed that POME treated in suspended growth system was able to remove 81.9% and 55.5% of the total nitrogen (TN) and total phosphorus (TP) respectively. Whereas the immobilized system showed lower removal of 77.22% and 53.02% for TN and TP. Lower performance of immobilized microalgae is due to the limited light penetration and supply of CO2 inside the immobilization materials. The rotating microalgae biofilm reactor was able to reduce the biochemical oxygen demand (BOD) to 90 mg/L and chemical oxygen demand (COD) to 720 mg/L. Higher BOD and COD reading were obtained in suspended growth due to the presence of small number of microalgae cell in the samples. This study shows that suspended growth system is able to remove higher percentages of nitrogen and phosphorus. However, an efficient separation method such as membrane filtration is required to harvest the cultivated microalgae cell to avoid organic matter release into water bodies.

Organics removal from landfill leachate and activated sludge production in SBR reactors

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

Klimiuk, Ewa; Kulikowska, Dorota

2006-07-01

This study is aimed at estimating organic compounds removal and sludge production in SBR during treatment of landfill leachate. Four series were performed. At each series, experiments were carried out at the hydraulic retention time (HRT) of 12, 6, 3 and 2 d. The series varied in SBR filling strategies, duration of the mixing and aeration phases, and the sludge age. In series 1 and 2 (a short filling period, mixing and aeration phases in the operating cycle), the relationship between organics concentration (COD) in the leachate treated and HRT was pseudo-first-order kinetics. In series 3 (with mixing and aerationmore » phases) and series 4 (only aeration phase) with leachate supplied by means of a peristaltic pump for 4 h of the cycle (filling during reaction period) - this relationship was zero-order kinetics. Activated sludge production expressed as the observed coefficient of biomass production (Y {sub obs}) decreased correspondingly with increasing HRT. The smallest differences between reactors were observed in series 3 in which Y {sub obs} was almost stable (0.55-0.6 mg VSS/mg COD). The elimination of the mixing phase in the cycle (series 4) caused the Y {sub obs} to decrease significantly from 0.32 mg VSS/mg COD at HRT 2 d to 0.04 mg VSS/mg COD at HRT 12 d. The theoretical yield coefficient Y accounted for 0.534 mg VSS/mg COD (series 1) and 0.583 mg VSS/mg COD (series 2). In series 3 and 4, it was almost stable (0.628 mg VSS/mg COD and 0.616 mg VSS/mg COD, respectively). After the elimination of the mixing phase in the operating cycle, the specific biomass decay rate increased from 0.006 d{sup -1} (series 3) to 0.032 d{sup -1} (series 4). The operating conditions employing mixing/aeration or only aeration phases enable regulation of the sludge production. The SBRs operated under aerobic conditions are more favourable at a short hydraulic retention time. At long hydraulic retention time, it can lead to a decrease in biomass concentration in the SBR as a result of cell decay. On the contrary, in the activated sludge at long HRT, a short filling period and operating cycle of the reactor with the mixing and aeration phases seem the most favourable.« less

Decolourization of remazol black-5 textile dyes using moving bed bio-film reactor

NASA Astrophysics Data System (ADS)

Pratiwi, R.; Notodarmojo, S.; Helmy, Q.

2018-01-01

The desizing and dyeing processes in the textile industries produces wastewaster containing high concentration of organic matter and colour, so it needs treatment before released to environment. In this research, removal of azo dye (Remazol Black 5/RB 5) and organic as COD was performed using Moving Bed Biofilm Reactor (MBBR). MBBR is biological treatment process with attached growth media system that can increase removal of organic matter in textile wastewater. The effectiveness of ozonation as pre-treatment process to increase the removal efficiency in MBBR was studied. The results showed that in MBBR batch system with detention time of 1 hour, pre-treatment with ozonation prior to MBBR process able to increase the colour removal efficiency of up to 86.74%. While on the reactor without ozone pre-treatment, the colour removal efficiency of up to 68.6% was achieved. From the continuous reactor experiments found that both colour and COD removal efficiency depends on time detention of RB-5 dyes in the system. The higher of detention time, the higher of colour and COD removal efficiency. It was found that optimum removal of colour and COD was achieved in 24 hour detention time with its efficiency of 96.9% and 89.13%, respectively.

Bio-hydrogen production from molasses by anaerobic fermentation in continuous stirred tank reactor

NASA Astrophysics Data System (ADS)

Han, Wei; Li, Yong-feng; Chen, Hong; Deng, Jie-xuan; Yang, Chuan-ping

2010-11-01

A study of bio-hydrogen production was performed in a continuous flow anaerobic fermentation reactor (with an available volume of 5.4 L). The continuous stirred tank reactor (CSTR) for bio-hydrogen production was operated under the organic loading rates (OLR) of 8-32 kg COD/m3 reactor/d (COD: chemical oxygen demand) with molasses as the substrate. The maximum hydrogen production yield of 8.19 L/d was obtained in the reactor with the OLR increased from 8 kg COD/m3 reactor/d to 24 kg COD/m3 d. However, the hydrogen production and volatile fatty acids (VFAs) drastically decreased at an OLR of 32 kg COD/m3 reactor/d. Ethanoi, acetic, butyric and propionic were the main liquid fermentation products with the percentages of 31%, 24%, 20% and 18%, which formed the mixed-type fermentation.

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.

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 .

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.

Treatment of high organic content wastewater from food-processing industry with the French vertical flow constructed wetland system.

PubMed

Paing, J; Serdobbel, V; Welschbillig, M; Calvez, M; Gagnon, V; Chazarenc, F

2015-01-01

This study aimed at determining the treatment performances of a full-scale vertical flow constructed wetlands designed to treat wastewater from a food-processing industry (cookie factory), and to study the influence of the organic loading rate. The full-scale treatment plant was designed with a first vertical stage of 630 m², a second vertical stage of 473 m² equipped with a recirculation system and followed by a final horizontal stage of 440 m². The plant was commissioned in 2011, and was operated at different loading rates during 16 months for the purpose of this study. Treatment performances were determined by 24 hour composite samples. The mean concentration of the raw effluent was 8,548 mg.L(-1) chemical oxygen demand (COD), 4,334 mg.L(-1) biochemical oxygen demand (BOD5), and 2,069 mg.L(-1) suspended solids (SS). Despite low nutrients content with a BOD5/N/P ratio of 100/1.8/0.5, lower than optimum for biological degradation (known as 100/5/1), mean removal performances were very high with 98% for COD, 99% for BOD5 and SS for the two vertical stages. The increasing of the organic load from 50 g.m(-2).d(-1) COD to 237 g.m(-2).d(-1) COD (on the first stage) did not affect removal performances. The mean quality of effluent reached French standards (COD < 125 mg.L(-1), BOD5 < 25 mg.L(-1), SS < 35 mg.L(-1)).

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts.

PubMed

Chen, C; Xie, Q; Hu, B Q; Zhao, X L

2014-01-01

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol-gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

Renewable Energy Production from DoD Installation Solid Wastes By Anaerobic Digestion

DTIC Science & Technology

2016-08-06

favorable environmental conditions including a mesophilic (37 oC) or thermophilic (55 oC) temperature , the absence of oxygen , and a pH between 6.5...a high temperature process that uses oxygen -starved combustion to convert dry organic matter to a syngas. Syngas is a low BTU fuel that can be used...production rates are at the 36.7 °C digester temperature . Parameter Units 7gCOD/L-d 12gCOD/L-d Effective SRT days 18.5 10.8 COD Conversion Efficiency % 67

Renewable Energy Production from DoD Installation Solid Wastes by Anaerobic Digestion

DTIC Science & Technology

2016-06-01

favorable environmental conditions including a mesophilic (37 oC) or thermophilic (55 oC) temperature , the absence of oxygen , and a pH between 6.5...a high temperature process that uses oxygen -starved combustion to convert dry organic matter to a syngas. Syngas is a low BTU fuel that can be used...production rates are at the 36.7 °C digester temperature . Parameter Units 7gCOD/L-d 12gCOD/L-d Effective SRT days 18.5 10.8 COD Conversion Efficiency % 67

Comparison between UV and VUV photolysis for the pre- and post-treatment of coking wastewater.

PubMed

Xing, Rui; Zheng, Zhongyuan; Wen, Donghui

2015-03-01

In this study, ultraviolet (UV) and vacuum ultraviolet (VUV) photolysis were investigated for the pre-treatment and post-treatment of coking wastewater. First, 6-fold diluted raw coking wastewater was irradiated by UV and VUV. It was found that 15.9%-35.4% total organic carbon (TOC) was removed after 24 hr irradiation. The irradiated effluent could be degraded by the acclimated activated sludge. Even though the VUV photolysis removed more chemical oxygen demand (COD) than UV, the UV-irradiated effluent demonstrated better biodegradability. After 4 hr UV irradiation, the biological oxygen demand BOD5/COD ratio of irradiated coking wastewater increased from 0.163 to 0.224, and its toxicity decreased to the greatest extent. Second, the biologically treated coking wastewater was irradiated by UV and VUV. Both of them were able to remove 37%-47% TOC within 8 hr irradiation. Compared to UV, VUV photolysis could significantly improve the transparency of the bio-treated effluent. VUV also reduced 7% more ammonia nitrogen (NH4+-N), 17% more nitrite nitrogen (NO2--N), and 18% more total nitrogen (TN) than UV, producing 35% less nitrite nitrogen (NO3--N) as a result. In conclusion, UV irradiation was better in improving the biodegradability of coking wastewater, while VUV was more effective at photolyzing the residual organic compounds and inorganic N-species in the bio-treated effluent. Copyright © 2015. Published by Elsevier B.V.

Anaerobic digestion of pressed off leachate from the organic fraction of municipal solid waste

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

Nayono, Satoto E.; Institute of Biology for Engineers and Biotechnology of Wastewater, University of Karlsruhe, Am Fasanengarten, 76131 Karlsruhe; Winter, Josef, E-mail: josef.winter@iba.uka.d

2010-10-15

A highly polluted liquid ('press water') was obtained from the pressing facility for the organic fraction of municipal solid waste in a composting plant. Methane productivity of the squeezed-off leachate was investigated in batch assays. To assess the technical feasibility of 'press water' as a substrate for anaerobic digestion, a laboratory-scale glass column reactor was operated semi-continuously at 37 {sup o}C. A high methane productivity of 270 m{sup -3} CH{sub 4} ton{sup -1} COD{sub added} or 490 m{sup -3} CH{sub 4} ton{sup -1} VS{sub added} was achieved in the batch experiment. The semi-continuously run laboratory-scale reactor was initially operated atmore » an organic loading rate of 10.7 kg COD m{sup -3} d{sup -1}. The loading was increased to finally 27.7 kg COD m{sup -3} d{sup -1}, corresponding to a reduction of the hydraulic retention time from initially 20 to finally 7.7 days. During the digestion, a stable elimination of organic material (measured as COD elimination) of approximately 60% was achieved. Linearly with the increment of the OLR, the volumetric methane production of the reactor increased from 2.6 m{sup 3} m{sub reactor}{sup -3} d{sup -1} to 7.1 m{sup 3} m{sub reactor}{sup -3} d{sup -1}. The results indicated that 'press water' from the organic fraction of municipal solid waste was a suitable substrate for anaerobic digestion which gave a high biogas yield even at very high loading rates.« less

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.

Preparation, Characterization and Adsorption Study of Granular Activated Carbon/Iron oxide composite for the Removal of Boron and Organics from Wastewater

NASA Astrophysics Data System (ADS)

Chioma Affam, Augustine; Chung Wong, Chee; Seyam, Mohammed A. B.; Matt, Chelsea Ann Anak Frederick; Lantan Anak Sumbai, Josephine; Evuti, Abdullahi Mohammed

2018-03-01

Boron and organics maybe in high concentration during production of oil and gas, fertilizers, glass, and detergents. In addition, boron added to these industrial processes may require to be removed by the wastewater treatment plant. The preparation, characterization and application of iron oxide-activated carbon composite for removal of boron and COD was studied. The one variable at a time (OVAT) method was implemented to obtain desirable operating conditions (adsorbent dosage 5 g/L, reaction time 2 h, agitation speed 100 rpm, pH 5 for COD removal and pH 9 for boron removal). It was found that boron and organics present in a sample wastewater may require to be treated separately to remove the contaminants. The study achieved 97 and 70% for boron and COD removal, respectively. Adsorption as an alternative cheap source of treatment and its practicability for small communities is recommended as effective in removal of contaminants from river water.

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.

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.

Data-driven event-by-event respiratory motion correction using TOF PET list-mode centroid of distribution

NASA Astrophysics Data System (ADS)

Ren, Silin; Jin, Xiao; Chan, Chung; Jian, Yiqiang; Mulnix, Tim; Liu, Chi; E Carson, Richard

2017-06-01

Data-driven respiratory gating techniques were developed to correct for respiratory motion in PET studies, without the help of external motion tracking systems. Due to the greatly increased image noise in gated reconstructions, it is desirable to develop a data-driven event-by-event respiratory motion correction method. In this study, using the Centroid-of-distribution (COD) algorithm, we established a data-driven event-by-event respiratory motion correction technique using TOF PET list-mode data, and investigated its performance by comparing with an external system-based correction method. Ten human scans with the pancreatic β-cell tracer 18F-FP-(+)-DTBZ were employed. Data-driven respiratory motions in superior-inferior (SI) and anterior-posterior (AP) directions were first determined by computing the centroid of all radioactive events during each short time frame with further processing. The Anzai belt system was employed to record respiratory motion in all studies. COD traces in both SI and AP directions were first compared with Anzai traces by computing the Pearson correlation coefficients. Then, respiratory gated reconstructions based on either COD or Anzai traces were performed to evaluate their relative performance in capturing respiratory motion. Finally, based on correlations of displacements of organ locations in all directions and COD information, continuous 3D internal organ motion in SI and AP directions was calculated based on COD traces to guide event-by-event respiratory motion correction in the MOLAR reconstruction framework. Continuous respiratory correction results based on COD were compared with that based on Anzai, and without motion correction. Data-driven COD traces showed a good correlation with Anzai in both SI and AP directions for the majority of studies, with correlation coefficients ranging from 63% to 89%. Based on the determined respiratory displacements of pancreas between end-expiration and end-inspiration from gated reconstructions, there was no significant difference between COD-based and Anzai-based methods. Finally, data-driven COD-based event-by-event respiratory motion correction yielded comparable results to that based on Anzai respiratory traces, in terms of contrast recovery and reduced motion-induced blur. Data-driven event-by-event respiratory motion correction using COD showed significant image quality improvement compared with reconstructions with no motion correction, and gave comparable results to the Anzai-based method.

Data-driven event-by-event respiratory motion correction using TOF PET list-mode centroid of distribution.

PubMed

Ren, Silin; Jin, Xiao; Chan, Chung; Jian, Yiqiang; Mulnix, Tim; Liu, Chi; Carson, Richard E

2017-06-21

Data-driven respiratory gating techniques were developed to correct for respiratory motion in PET studies, without the help of external motion tracking systems. Due to the greatly increased image noise in gated reconstructions, it is desirable to develop a data-driven event-by-event respiratory motion correction method. In this study, using the Centroid-of-distribution (COD) algorithm, we established a data-driven event-by-event respiratory motion correction technique using TOF PET list-mode data, and investigated its performance by comparing with an external system-based correction method. Ten human scans with the pancreatic β-cell tracer 18 F-FP-(+)-DTBZ were employed. Data-driven respiratory motions in superior-inferior (SI) and anterior-posterior (AP) directions were first determined by computing the centroid of all radioactive events during each short time frame with further processing. The Anzai belt system was employed to record respiratory motion in all studies. COD traces in both SI and AP directions were first compared with Anzai traces by computing the Pearson correlation coefficients. Then, respiratory gated reconstructions based on either COD or Anzai traces were performed to evaluate their relative performance in capturing respiratory motion. Finally, based on correlations of displacements of organ locations in all directions and COD information, continuous 3D internal organ motion in SI and AP directions was calculated based on COD traces to guide event-by-event respiratory motion correction in the MOLAR reconstruction framework. Continuous respiratory correction results based on COD were compared with that based on Anzai, and without motion correction. Data-driven COD traces showed a good correlation with Anzai in both SI and AP directions for the majority of studies, with correlation coefficients ranging from 63% to 89%. Based on the determined respiratory displacements of pancreas between end-expiration and end-inspiration from gated reconstructions, there was no significant difference between COD-based and Anzai-based methods. Finally, data-driven COD-based event-by-event respiratory motion correction yielded comparable results to that based on Anzai respiratory traces, in terms of contrast recovery and reduced motion-induced blur. Data-driven event-by-event respiratory motion correction using COD showed significant image quality improvement compared with reconstructions with no motion correction, and gave comparable results to the Anzai-based method.

Elutriated acid fermentation of municipal primary sludge.

PubMed

Ahn, Young Ho; Speece, Richard E

2006-06-01

The performance of a novel fermentation process, adopting a sludge blanket type configuration, for higher hydrolysis/acidogenesis of the municipal primary sludge was investigated under batch and semi-continuous conditions with varying pH and temperature. This acid elutriation slurry reactor provided higher system performance with a short HRT (5d) and higher acidogenic effluent quality under pH 9 and thermophilic (55 degrees C) conditions. The hydrolysis of the sludge was revealed to be significantly dependent on seasonal effects for sludge characteristics but with little impact on acidogenesis. Based on the rainy season at the optimal conditions, VFA production and recovery fraction (VFA(COD)/COD) were 0.18 g VFA(COD)/g VSS(COD) and 63%. As byproducts, nitrogen and phosphorus release were measured at 0.006 g N/g VSS(COD) and 0.003 g P/g VSS(COD), respectively. For the mass balance in a full-scale plant (Q=158,880 m(3)/d) based on the rainy season, the VFA and non-VFA (as COD) production were 3110 kg VFA(COD)/d and 1800 kg COD/d, resulting in an increase of organics of 31 mg COD/L and 20mg VFA(COD)/L and nutrients of 0.7 mg N/L and 0.3 mg P/L in the influent sewage. The economical benefit from this process application was estimated to be about 67 dollars per 1000 m(3) of sewage except for energy requirements and also, better benefits can be expected during the dry season. Moreover, the results revealed that the process has various additional advantages such as pathogen-free stabilized solids production, excellent solids control and economical benefits.

Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA

USGS Publications Warehouse

Smith, Richard L.; Repert, Deborah A.; Barber, Larry B.; LeBlanc, Denis R.

2013-01-01

The consequences of groundwater contamination can remain long after a contaminant source has been removed. Documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and associated geochemical changes are generally lacking. This study characterized the long-term natural attenuation of a groundwater contaminant plume in a sand and gravel aquifer on Cape Cod, Massachusetts, after the removal of the treated-wastewater source. Although concentrations of dissolved organic carbon (DOC) and other soluble constituents have decreased substantially in the 15 years since the source was removed, the core of the plume remains anoxic and has sharp redox gradients and elevated concentrations of nitrate and ammonium. Aquifer sediment was collected from near the former disposal site at several points in time and space along a 0.5-km-long transect extending downgradient from the disposal site and analyses of the sediment was correlated with changes in plume composition. Total sediment carbon content was generally low (< 8 to 55.8 μmol (g dry wt)− 1) but was positively correlated with oxygen consumption rates in laboratory incubations, which ranged from 11.6 to 44.7 nmol (g dry wt)− 1 day− 1. Total water extractable organic carbon was < 10–50% of the total carbon content but was the most biodegradable portion of the carbon pool. Carbon/nitrogen (C/N) ratios in the extracts increased more than 10-fold with time, suggesting that organic carbon degradation and oxygen consumption could become N-limited as the sorbed C and dissolved inorganic nitrogen (DIN) pools produced by the degradation separate with time by differential transport. A 1-D model using total degradable organic carbon values was constructed to simulate oxygen consumption and transport and calibrated by using observed temporal changes in oxygen concentrations at selected wells. The simulated travel velocity of the oxygen gradient was 5–13% of the groundwater velocity. This suggests that the total sorbed carbon pool is large relative to the rate of oxygen entrainment and will be impacting groundwater geochemistry for many decades. This has implications for long-term oxidation of reduced constituents, such as ammonium, that are being transported downgradient away from the infiltration beds toward surface and coastal discharge zones.

Electrosorption of organic acids from aqueous bio-oil and conversion into hydrogen via microbial electrolysis cells

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

Park, Lydia Kyoung-Eun; Satinover, Scott J.; Yiacoumi, Sotira

Neutralization of the bio-oil pH has been shown to generate a neutralized bio-oil aqueous phase (NBOAP) that includes most of the acidic components and a neutralized bio-oil organic phase (NBOOP) that includes hydrophobic organics, such as phenols. NBOOP can be used for fuel production, while NBOAP can be fed to microbial electrolysis cells (MECs) for hydrogen production. After pH neutralization, some organic acidic components remain in NBOOP. This work is focused on capturing acidic compounds from NBOOP through water extraction and electrosorption, and demonstrating hydrogen production via MECs. Capacitive deionization (CDI) is proven effective in capturing ions from NBOOP-contacted watermore » and NBOAP via electrosorption. Captured acidic compounds enable the MEC application to effectively produce renewable hydrogen. Chemical oxygen demand (COD) removal of 49.2%, 61.5%, and 60.8% for 2, 4, and 10 g/L-anode/day loading were observed, corresponding to a total COD degradation of 0.19 g/L, 0.79 g/L, and 1.3 g/L, respectively. A maximum hydrogen productivity of 4.3 L-H 2/L-anode/day was obtained. Major compounds in the water phase such as fatty acids, sugar derivatives, furanic and phenolic compounds were converted to hydrogen with an efficiency of 80–90%. Lastly, this approach may lead the entire biomass pyrolysis process to be an overall carbon-neutral process.« less

Electrosorption of organic acids from aqueous bio-oil and conversion into hydrogen via microbial electrolysis cells

DOE PAGES

Park, Lydia Kyoung-Eun; Satinover, Scott J.; Yiacoumi, Sotira; ...

2018-02-17

Neutralization of the bio-oil pH has been shown to generate a neutralized bio-oil aqueous phase (NBOAP) that includes most of the acidic components and a neutralized bio-oil organic phase (NBOOP) that includes hydrophobic organics, such as phenols. NBOOP can be used for fuel production, while NBOAP can be fed to microbial electrolysis cells (MECs) for hydrogen production. After pH neutralization, some organic acidic components remain in NBOOP. This work is focused on capturing acidic compounds from NBOOP through water extraction and electrosorption, and demonstrating hydrogen production via MECs. Capacitive deionization (CDI) is proven effective in capturing ions from NBOOP-contacted watermore » and NBOAP via electrosorption. Captured acidic compounds enable the MEC application to effectively produce renewable hydrogen. Chemical oxygen demand (COD) removal of 49.2%, 61.5%, and 60.8% for 2, 4, and 10 g/L-anode/day loading were observed, corresponding to a total COD degradation of 0.19 g/L, 0.79 g/L, and 1.3 g/L, respectively. A maximum hydrogen productivity of 4.3 L-H 2/L-anode/day was obtained. Major compounds in the water phase such as fatty acids, sugar derivatives, furanic and phenolic compounds were converted to hydrogen with an efficiency of 80–90%. Lastly, this approach may lead the entire biomass pyrolysis process to be an overall carbon-neutral process.« less

Effect of agitation on methanogenesis stage of two-stage anaerobic digestion of palm oil mill effluent (POME) into biogas

NASA Astrophysics Data System (ADS)

Trisakti, Bambang; Irvan, Zahara, Intan; Taslim, Turmuzi, Muhammad

2017-05-01

This study is an assessment of the effect of agitation on biogas production on methanogenesis stage. Methanogenesis is the second stage of two-stage anaerobic digestion of palm oil effluent (POME) into biogas. The purpose of this study is to get the effect of agitation on growth of microorganisms, degradation of organic substances, and biogas production and composition. Initially, the suitable loading up was determined by varying the HRT at 100, 40, 6, and 4 days in the continuous stirred tank reactor (CSTR) with agitation rate 100 rpm, pH 6.7-7.5, at room temperature. Next, effect of agitation on the process was determined by varying agitation rate at 50, 100, 150, and 200 rpm. The substrate used was the effluent of the acidogenesis stage that fed to the CSTR four times a day. Analysis of total solids (TS), volatile solids (VS), total suspended solids (TSS), volatile suspended solids (VSS), and chemical oxygen demand (COD) were conducted in order to study the growth of microorganisms and their abilities in converting organic compound to produce biogas. Production and composition of biogas were also determined by measuring the volume of biogas and content of H2S and CO2. The result showed that the pH and alkalinity it was still within the range of methanogenesis process. The growth of microorganisms were increased with the increasing of agitation rate. However, the best degradation of organic substances, biogas production, and biogas composition were achieved at 100 rpm. The VS decomposition, COD removal, biogas production, CO2 content, and CH4 content at 100 rpm were 67.44 ± 3.59%, 81.00%, 58.87 ± 6.27 L/kg-ΔVS, 23.36%, and 76.64%, respectively.

Sustainable treatment of different high-strength cheese whey wastewaters: an innovative approach for atmospheric CO2 mitigation and fertilizer production.

PubMed

Prazeres, Ana R; Rivas, Javier; Paulo, Úrsula; Ruas, Filipa; Carvalho, Fátima

2016-07-01

Raw cheese whey wastewater (CWW) has been treated by means of FeCl3 coagulation-flocculation, NaOH precipitation, and Ca(OH)2 precipitation. Three different types of CWW were considered: without cheese whey recovery (CWW0), 60 % cheese whey recovery (CWW60), and 80 % cheese whey recovery (CWW80). Cheese whey recovery significantly influenced the characteristics of the wastewater to be treated: organic matter, solids, turbidity, conductivity, sodium, chloride, calcium, nitrogen, potassium, and phosphorus. Initial organic load was reduced to values in the interval of 60-70 %. Application of FeCl3, NaOH, or Ca(OH)2 involved additional chemical oxygen demand (COD) depletions regardless of the CWW used. Under optimum conditions, the combination of 80 % cheese whey recovery and lime application led to 90 % reduction in COD. Turbidity (99.8%), total suspended solids (TSS) (98-99 %), oils and fats (82-96 %), phosphorus (98-99 %), potassium (96-97 %), and total coliforms (100 %) were also reduced. Sludge generated in the latter process showed excellent settling properties. This solid after filtration and natural evaporation can be used as fertilizer with limitations due to its saline nature. In an innovative, low-cost, and environmentally friendly technology, supernatant coming from the Ca(OH)2 addition was naturally neutralized in 4-6 days by atmospheric CO2 absorption without reagent addition. Consequently, a final aerobic biodegradation step can be applied for effluent polishing. This technology also allows for some atmospheric CO2 mitigation. Time requirement for the natural carbonation depends on the effluent characteristics. A precipitate rich in organic matter and nutrients and depletions of solids, sodium, phosphorus, magnesium, Kjeldahl, and ammoniacal nitrogen were also achieved during the natural carbonation.

Preparation of Ti/IrO2 Anode with Low Iridium Content by Thermal Decomposition Process: Electrochemical removal of organic pollutants in water

NASA Astrophysics Data System (ADS)

Yaqub, Asim; Isa, Mohamed Hasnain; Ajab, Huma; Kutty, S. R. M.; Ezechi, Ezerie H.; Farooq, Robina

2018-04-01

In this study IrO2 (Iridium oxide) was coated onto a titanium plate anode from a dilute (50 mg/10 ml) IrCl3×H2O salt solution. Coating was done at high temperature (550∘C) using thermal decomposition. Surface morphology and characteristics of coated surface of Ti/IrO2 anode were examined by FESEM and XRD. The coated anode was applied for electrochemical removal of organic pollutants from synthetic water samples in 100 mL compartment of batch electrochemical cell. About 50% COD removal was obtained at anode prepared with low Ir content solution while 72% COD removal was obtained with anode prepared at high Ir content. Maximum COD removal was obtained at 10 mA/cm2 current density.

Absorption and fluorescence properties of chromophoric dissolved organic matter: implications for the monitoring of water quality in a large subtropical reservoir.

PubMed

Liu, Xiaohan; Zhang, Yunlin; Shi, Kun; Zhu, Guangwei; Xu, Hai; Zhu, Mengyuan

2014-12-01

The development of techniques for real-time monitoring of water quality is of great importance for effectively managing inland water resources. In this study, we first analyzed the absorption and fluorescence properties in a large subtropical reservoir and then used a chromophoric dissolved organic matter (CDOM) fluorescence monitoring sensor to predict several water quality parameters including the total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), dissolved organic carbon (DOC), and CDOM fluorescence parallel factor analysis (PARAFAC) components in the reservoir. The CDOM absorption coefficient at 254 nm (a(254)), the humic-like component (C1), and the tryptophan-like component (C3) decreased significantly along a gradient from the northwest to the lake center, northeast, southwest, and southeast region in the reservoir. However, no significant spatial difference was found for the tyrosine-like component (C2), which contributed only four marked peaks. A highly significant linear correlation was found between the a(254) and CDOM concentration measured using the CDOM fluorescence sensor (r(2) = 0.865, n = 76, p < 0.001), indicating that CDOM concentrations could act as a proxy for the CDOM absorption coefficient measured in the laboratory. Significant correlations were also found between the CDOM concentration and TN, TP, COD, DOC, and the maximum fluorescence intensity of C1, suggesting that the real-time monitoring of CDOM concentrations could be used to predict these water quality parameters and trace the humic-like fluorescence substance in clear aquatic ecosystems with DOC <2 mg/L and total suspended matter (TSM) concentrations <15 mg/L. These results demonstrate that the CDOM fluorescence sensor is a useful tool for on-line water quality monitoring if the empirical relationship between the CDOM concentration measured using the CDOM fluorescence sensor and the water quality parameters is calibrated and validated.

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.

Degradation and COD removal of catechol in wastewater using the catalytic ozonation process combined with the cyclic rotating-bed biological reactor.

PubMed

Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

2015-07-01

The effect of ozonation catalyzed with MgO/granular activated carbon (MgO/GAC) composite as a pretreatment process on the performance of cyclic rotating-bed biological reactor (CRBR) for the catechol removal from wastewater has been investigated. CRBR with acclimated biomasses could efficiently remove catechol and its related COD from wastewater at organic loading rate (OLR) of 7.82 kg COD/m(3).d (HRT of 9 h). Then, OLR increased to 15.64 kg COD/m(3).d (HRT of 4.5 h) and CRBR failed. Catalytic ozonation process (COP) used as a pre-treatment and could improve the performance of the failed CRBR. The overall removal efficiency of the combined process attained respective steady states of 91% and 79% for degradation and COD removal of catechol. Therefore, the combined process is more effective in degradation and COD removal of catechol; it is also a viable alternative for upgrading industrial wastewater treatment plant. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using full-scale duckweed ponds as the finish stage for swine waste treatment with a focus on organic matter degradation.

PubMed

Mohedano, R A; Costa, R H R; Hofmann, S M; Belli Filho, P

2014-01-01

The rapid increase in the number of swine has caused pronounced environmental impacts worldwide, especially on water resources. As an aggregate, smallholdings have an important role in South American pork production, contributing to the net diffusion of pollution. Thus, duckweed ponds have been successfully used for swine waste polishing, mainly for nutrient removal. Few studies have been carried out to assess organic matter degradation in duckweed ponds. Hence, the present study evaluated the efficiency of two full-scale duckweed ponds for organic matter reduction of swine waste on small pig farms. Duckweed ponds, in series, received the effluent after an anaerobic biodigester and storage pond, with a flow rate of 1 m(3) day(-1). After 1 year of monitoring, an improvement in effluent quality was observed, with a reduction in biochemical oxygen demand (BOD) and total chemical oxygen demand (tCOD), respectively, of 94.8 and 96.7%, operating at a loading rate of approximately 27 kgBOD ha(-1) day(-1) and 131 kgCOD ha(-1) day(-1). Algae inhibition due to duckweed coverage was strongly observed in the pond effluent, where chlorophyll a and turbidity remained below 25 μg L(-1) and 10 NTU. Using the study conditions described herein, duckweed ponds were shown to be a suitable technology for swine waste treatment, contributing to the environmental sustainability of rural areas.

Effect of packing material on organic matter removal efficiency in an anaerobic-aerobic baffled bioreactor.

PubMed

Tabla-Hernandez, Jacobo; Lopez-Galvan, Edgar

2018-04-01

The aim of the present work was to study the effect of packing material on the organic matter removal efficiency (OMRE) in an anaerobic-aerobic baffled bioreactor (AAB). For this purpose, two different experiments were conducted with two types of packing material: activated carbon (AC) particles and polyurethane foam (PF). The system consisted of two treatments; the first one was anaerobic, where hydrolysis, acetogenesis and methanogenesis took place. In anaerobic chambers, there were no packing materials and the operating conditions were the same in both experiments. The second treatment was aerobic and both materials were placed at different times as a bedding. The parameters measured were chemical oxygen demand (COD), dissolved chemical oxygen demand (COD d ), total organic carbon (TOC), nitrate concentration (NO 3 - ), ammonium concentration (NH 4 + ), electric conductivity (σ), alkalinity (Alky) and hydrogen potential (pH). Paired t-Student test showed that there was no significant difference in the OMRE in anaerobic treatment, whereas there was in aerobic treatment, due to the effect of packing material. NH 4 + and NO 3 - showed a negative Pearson correlation in both experiments, indicating the presence of the nitrification process in the aerobic chamber. AAB packed with PF had better performance at obtaining an OMRE of around 63%, whereas AAB packed with AC presented an OMRE of around 51%.

Bioaccumulation of organic contaminants in the liver and blubber of pilot whales (Globicephala melaena) beached on Cape Cod, MA

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

Weisbrod, A.V.; Shea, D.; Moore, M.J.

1995-12-31

Populations of many marine organisms in Boston Harbor and Massachusetts Bay have been declining for decades. Overfishing, habitat loss, disease, and exposure to toxic contaminants have been implicated as causative factors for reductions in both commercially important species and endangered marine mammal populations. The purpose of this study was to determine if exposure to organic contaminants could be a factor in the pilot whale population decline and to develop a simple bioaccumulation model to assess the relative importance of the route of uptake and the significance of total elimination. Liver and blubber samples from ten individuals beached in 1991 onmore » Cape Cod, MA were analyzed by gas chromatography/electron capture detection (GC/ECD) and gas chromatography/mass spectrometry (GC/MS) for polychlorinated biphenyls (PCBs), chlorinated pesticides, polycyclic aromatic hydrocarbons (PAHs), and linear alkyl benzenes (LABs). PCBs, DDT, DDE, DDD, and other chlorinated pesticides were identified and found to be high (ppm range) in several individuals. PAHs and LABs were typically below one ppb. Concentrations of these contaminants in the water and food that pilot whales consume were used in a bioaccumulation model. The model predicted lower concentrations in the whale than the authors observed. For all but the least hydrophobic contaminants (e.g., naphthalene) they predict that food (biomagnification) is the dominant route of uptake into the whales.« less

Eukaryotic Community Shift in Response to Organic Loading Rate of an Aerobic Trickling Filter (Down-Flow Hanging Sponge Reactor) Treating Domestic Sewage.

PubMed

Miyaoka, Yuma; Hatamoto, Masashi; Yamaguchi, Takashi; Syutsubo, Kazuaki

2017-05-01

In this study, changes in eukaryotic community structure and water quality were investigated in an aerobic trickling filter (down-flow hanging sponge, DHS) treating domestic sewage under different organic loading rates (OLRs). The OLR clearly influenced both sponge pore water quality and relative flagellates and ciliates (free-swimming, carnivorous, crawling, and stalked protozoa) abundances in the retained sludge. Immediately after the OLR was increased from 1.05 to 1.97 kg chemical oxygen demand (COD) m -3  day -1 , COD and NH 4 + -N treatment efficiencies both deteriorated, and relative flagellates and ciliates abundances then increased from 2-8 % to 51-65 % total cells in the middle-bottom part of the DHS reactor. In a continuous operation at a stable OLR (2.01 kg COD m -3  day -1 ), effluent water quality improved, and relative flagellates and ciliates abundances decreased to 15-46 % total cells in the middle-bottom part of the DHS reactor. This result may indicate that flagellates and ciliates preferentially graze on dispersed bacteria, thus, stabilizing effluent water quality. Additionally, to investigate eukaryotic community structure, clone libraries based on the 18S ribosomal ribonucleic acid (rRNA) gene of the retained sludge were constructed. The predominant group was Nucletmycea phylotypes, representing approximately 29-56 % total clones. Furthermore, a large proportion of the clones had <97 % sequence identity in the NCBI database. This result indicates that phylogenetically unknown eukaryotes were present in the DHS reactor. These results provide insights into eukaryotic community shift in the DHS reactor treating domestic sewage.

Mesophilic co-digestion of palm oil mill effluent and empty fruit bunches.

PubMed

Kim, Sang-Hyoun; Choi, Seon-Mi; Ju, Hyun-Jun; Jung, Jin-Young

2013-01-01

The palm oil mill industry generates palm oil mill effluent (POME) and empty fruit bunches (EFB) as by-products. This study reports the mesophilic co-digestion of POME with EFB. The biochemical methane potential (BMP) of POME and EFB was 0.397 L CH4/g volatile solids (VS) and 0.264 L CH4/g VS, respectively. In a series of batch tests at various EFB to POME ratios, the maximum methane production rate was achieved at an EFB:POME ratio of 0.25-0.31:1. Performance data from lab-scale digesters confirmed the positive synergism by the addition of EFB to POME, which was attributed to the balanced chemical composition, for example the chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio. The EFB addition enhanced the acceptable organic loading rate, methane production, COD removal, and microbial activity. The mesophilic co-digestion of POME and EFB promises to be a viable recycling method to alleviate pollution problems and recover renewable energy in the palm oil mill industry.

Treatment of diazo dye C.I. Reactive Black 5 in aqueous solution by combined process of interior microelectrolysis and ozonation.

PubMed

Guo, Xiaoyan; Cai, Yaping; Wei, Zhongbo; Hou, Haifeng; Yang, Xi; Wang, Zunyao

2013-01-01

Interior microelectrolysis (IM) as a pretreatment process was effective to treat Reactive Black 5 (RB5) in this study. The removal rates of chemical oxygen demand (COD), total organic carbon (TOC) and color were 46.05, 39.99 and 98.77%, respectively, when this process was conducted under the following optimal conditions: the volumetric ratio between iron scraps and active carbon (AC) (V(Fe)/V(C)) 1.0, pH 2.0, aeration dosage 0.6 L/min, and reaction time 100 min. Contaminants could be further removed by ozonation. After subsequent ozonation for 200 min, the solution could be completely decolorized, and the COD and TOC removal rates were up to 77.78 and 66.51%, respectively. In addition, acute toxicity tests with Daphnia magna showed that pretreatment by IM generated effluents that were more toxic when compared with the initial wastewater, and the toxicity was reduced after subsequent ozonation.

The structure optimization of gas-phase surface discharge and its application for dye degradation

NASA Astrophysics Data System (ADS)

Ying, CAO; Jie, LI; Nan, JIANG; Yan, WU; Kefeng, SHANG; Na, LU

2018-05-01

A gas-phase surface discharge (GSD) was employed to optimize the discharge reactor structure and investigate the dye degradation. A dye mixture of methylene blue, acid orange and methyl orange was used as a model pollutant. The results indicated that the reactor structure of the GSD system with the ratio of tube inner surface area and volume of 2.48, screw pitch between a high-voltage electrode of 9.7 mm, high-voltage electrode wire diameter of 0.8 mm, dielectric tube thickness of 2.0 mm and tube inner diameter of 16.13 mm presented a better ozone (O3) generation efficiency. Furthermore, a larger screw pitch and smaller wire diameter enhanced the O3 generation. After the dye mixture degradation by the optimized GSD system, 73.21% and 50.74% of the chemical oxygen demand (COD) and total organic carbon removal rate were achieved within 20 min, respectively, and the biochemical oxygen demand (BOD) and biodegradability (BOD/COD) improved.

Membrane bioreactor treatment of a simulated metalworking fluid wastewater containing ethylenediaminetetraacetic acid and dicyclohexylamine.

PubMed

Anderson, James E; Lofton, Tiffany V; Kim, Byung R; Mueller, Sherry A

2009-04-01

Membrane bioreactors (MBRs) have been installed at automotive plants to treat metalworking fluid (MWF) wastewaters, which are known to contain toxic and/or recalcitrant organic compounds. A laboratory study was conducted to evaluate treatment of a simulated wastewater prepared from a semisynthetic MWF, which contains two such compounds, dicyclohexylamine (DCHA) and ethylenediaminetetraacetic acid (EDTA). Primary findings were as follows: During stable operating periods, almost all chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and EDTA were removed (by > 96%). During somewhat unstable periods, COD removal was still extremely robust, but removal of EDTA and TKN were sensitive to prolonged episodes of low dissolved oxygen. Nitrogen mass balance suggested 30 to 40% TKN removal by assimilation and 60 to 70% by nitrification (including up to 34% TKN removal via subsequent denitrification). Dicyclohexylamine appeared to be readily biodegraded. Maximum DCHA and EDTA degradation rates between pH 7 and 8 were found. An Arthrobacter sp. capable of growth on DCHA as the sole source of carbon and energy was isolated.

Effects of ultrasound pre-treatment on the amount of dissolved organic matter extracted from food waste.

PubMed

Jiang, Jianguo; Gong, Changxiu; Wang, Jiaming; Tian, Sicong; Zhang, Yujing

2014-03-01

This paper describes a series of studies on the effects of food waste disintegration using an ultrasonic generator and the production of volatile fatty acids (VFAs) by anaerobic hydrolysis. The results suggest that ultrasound treatment can significantly increase COD [chemical oxygen demand], proteins and reducing sugars, but decrease that of lipids in food waste supernatant. Ultrasound pre-treatment boosted the production of VFAs dramatically during the fermentation of food waste. At an ultrasonic energy density of 480W/L, we treated two kinds of food waste (total solids (TS): 40 and 100g/L, respectively) with ultrasound for 15min. The amount of COD dissolved from the waste increased by 1.6-1.7-fold, proteins increased by 3.8-4.3-fold, and reducing sugars increased by 4.4-3.6-fold, whereas the lipid content decreased from 2 to 0.1g/L. Additionally, a higher VFA yield was observed following ultrasonic pre-treatment. Copyright © 2013 Elsevier Ltd. 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.

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.

Evaluation of Autothermal Thermophilic Aerobic Digester Performance for the Stabilization of Municipal Wastewater Sludge.

PubMed

Shokoohi, Reza; Rahmani, Alireza; Asgari, Ghorban; Dargahi, Abdollah; Vaziri, Yaser; Abbasi, Mohammad Attar

2017-01-01

Sludge stabilization process in terms of operational, environmental and economic indexes is the most important stage of treatment and its disposal. This study was aimed to determine the performance of Autothermal Thermophilic Aerobic Digestion (ATAD) system as one of the low-cost and biocompatible methods of sludge treatment. This study has been done using a laboratory scale Autothermal Thermophilic Aerobic Digestion (ATAD). The reactor was consisted of two polyethylene tanks with a final capacity of 100 L for each tank. Both tanks with all fittings were installed on a metal frame. The variables of study were temperature, dissolved oxygen, pH, volatile organic compounds, total solids, COD and the number of Ascaris eggs and fecal coliforms per gram of dry matter of the sludge. The temperature was measured hourly and the pH and dissolved oxygen were measured and controlled twice per day. One-way ANNOVA was applied to analyze reasults. According to the results, the temperature of sludge increased from 11.7-61.2°C by biological reactions. Pathogen organisms were reduced from 80×106 to 503 in number during 72 h. After 6 days pathogen organisms and Ascaris eggs were removed completely. Volatile organic compounds and COD were reduced 42 and 38.3% respectively during the 6 days. It is concluded that the performance of ATAD in removing organic compounds from wastewater sludge were desirable. Resulted sludge from stabilization process were appropriate for use in agriculture as a soil supplement and met the indexes of class A sludge according to EPA's standards (CFR 40 Part 503).

Bacterial community analysis of anoxic/aeration (A/O) system in a combined process for gibberellin wastewater treatment

PubMed Central

Ouyang, Erming; Lu, Yao; Ouyang, Jiating; Wang, Lele; Wang, Xiaohui

2017-01-01

Gibberellin wastewater cannot be directly discharged without treatment due to its high concentrations of sulfate and organic compounds and strong acidity. Therefore, multi-stage anaerobic bioreactor + micro-aerobic+ anoxic/aeration (A/O) + biological contact oxidation combined processes are used to treat gibberellin wastewater. However, knowledge of the treatment effects of the A/O process and bacterial community structure in the aeration tank reactors of such systems is sparse. Therefore, this study was conducted to investigate the treatment effects and operation of the A/O process on gibberellin wastewater, as well as changes in the bacterial community structure of activated sludge in the aeration tank during treatment. Moreover, removal was examined based on evaluation of effluent after A/O treatment. Although influent chemical oxygen demand (COD), NH3-N and total phosphorus (TP) fluctuated, effluent COD, NH3-N and TP remained stable. Moreover, average COD, NH3-N and TP removal efficiency were 68.41%, 93.67% and 45.82%, respectively, during the A/O process. At the phylum level, Proteobacteria was the dominant phylum in all samples, followed by Chloroflexi, Bacteroidetes and Actinobacteria. Proteobacteria played an important role in the removal of organic matter. Chloroflexi was found to be responsible for the degradation of carbohydrates and Bacteroidetes also had been found to be responsible for the degradation of complex organic matters. Actinobacteria are able to degrade a variety of environmental chemicals. Additionally, Anaerolineaceae_uncultured was the major genus in samples collected on May 25, 2015, while Novosphingobium and Nitrospira were dominant in most samples. Nitrosomonas are regarded as the dominant ammonia-oxidizing bacteria, while Nitrospira are the main nitrite-oxidizing bacteria. Bacterial community structure varied considerably with time, and a partial Mantel test showed a highly significant positive correlation between bacterial community structure and DO. The bacterial community structure was also positively correlated with temperature and SO42-. PMID:29053751

Performance of a lab-scale bio-electrochemical assisted septic tank for the anaerobic treatment of black water.

PubMed

Zamalloa, Carlos; Arends, Jan B A; Boon, Nico; Verstraete, Willy

2013-06-25

Septic tanks are used for the removal of organic particulates in wastewaters by physical accumulation instead of through the biological production of biogas. Improved biogas production in septic tanks is crucial to increase the potential of this system for both energy generation and organic matter removal. In this study, the effect on the biogas production and biogas quality of coupling a 20 L lab-scale septic tank with a microbial electrolysis cell (MEC) was investigated and compared with a standard septic tank. Both reactors were operated at a volumetric organic loading rate of 0.5gCOD/Ld and a hydraulic retention time between 20 and 40 days using black water as an input under mesophilic conditions for a period of 3 months. The MEC-septic tank was operated at an applied voltage of 2.0±0.1V and the current experienced ranged from 40 mA (0.9A/m(2) projected electrode area) to 180 mA (5A/m(2) projected electrode area). The COD removal was of the order of 85% and the concentration of residual COD was not different between both reactors. Yet, the total phosphorous in the output was on average 39% lower in the MEC-septic tank. Moreover, the biogas production rate in the MEC-septic tank was a factor of 5 higher than in the control reactor and the H2S concentration in the biogas was a factor of 2.5 lower. The extra electricity supplied to the MEC-septic tank was recovered as extra biogas produced. Overall, it appears that the combination of MEC and a septic tank offers perspectives in terms of lower discharge of phosphorus and H2S, nutrient recuperation and a more reliable supply of biogas. Copyright © 2013 Elsevier B.V. All rights reserved.

Removal of algal blooms from freshwater by the coagulation-magnetic separation method.

PubMed

Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

2013-01-01

This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.

Evaluation of constructed wetland treatment performance for winery wastewater.

PubMed

Grismer, Mark E; Carr, Melanie A; Shepherd, Heather L

2003-01-01

Rapid expansion of wineries in rural California during the past three decades has created contamination problems related to winery wastewater treatment and disposal; however, little information is available about performance of on-site treatment systems. Here, the project objective was to determine full-scale, subsurface-flow constructed wetland retention times and treatment performance through assessment of water quality by daily sampling of total dissolved solids, pH, total suspended solids, chemical oxygen demand (COD), tannins, nitrate, ammonium, total Kjeldahl nitrogen, phosphate, sulfate, and sulfide across operating systems for winery wastewater treatment. Measurements were conducted during both the fall crush season of heavy loading and the spring following bottling and racking operations at the winery. Simple decay model coefficients for these constituents as well as COD and tannin removal efficiencies from winery wastewater in bench-scale reactors are also determined. The bench-scale study used upward-flow, inoculated attached-growth (pea-gravel substrate) reactors fed synthetic winery wastewater. Inlet and outlet tracer studies for determination of actual retention times were essential to analyses of treatment performance from an operational subsurface-flow constructed wetland that had been overloaded due to failure to install a pretreatment system for suspended solids removal. Less intensive sampling conducted at a smaller operational winery wastewater constructed wetland that had used pretreatment suspended solids removal and aeration indicated that the constructed wetlands were capable of complete organic load removal from the winery wastewater.

Sewage sludge disintegration by high-pressure homogenization: a sludge disintegration model.

PubMed

Zhang, Yuxuan; Zhang, Panyue; Ma, Boqiang; Wu, Hao; Zhang, Sheng; Xu, Xin

2012-01-01

High-pressure homogenization (HPH) technology was applied as a pretreatment to disintegrate sewage sludge. The effects of homogenization pressure, homogenization cycle number, and total solid content on sludge disintegration were investigated. The sludge disintegration degree (DD(COD)), protein concentration, and polysaccharide concentration increased with the increase of homogenization pressure and homogenization cycle number, and decreased with the increase of sludge total solid (TS) content. The maximum DD(COD) of 43.94% was achieved at 80 MPa with four homogenization cycles for a 9.58 g/L TS sludge sample. A HPH sludge disintegration model of DD(COD) = kNaPb was established by multivariable linear regression to quantify the effects of homogenization parameters. The homogenization cycle exponent a and homogenization pressure exponent b were 0.4763 and 0.7324 respectively, showing that the effect of homogenization pressure (P) was more significant than that of homogenization cycle number (N). The value of the rate constant k decreased with the increase of sludge total solid content. The specific energy consumption increased with the increment of sludge disintegration efficiency. Lower specific energy consumption was required for higher total solid content sludge.

Electricity Generation and Community Wastewater Treatment by Microbial Fuel Cells (MFCs)

NASA Astrophysics Data System (ADS)

Rakthai, S.; Potchanakunakorn, R.; Changjan, A.; Intaravicha, N.; Pramuanl, P.; Srigobue, P.; Soponsathien, S.; Kongson, C.; Maksuwan, A.

2018-05-01

The attractive solution to the pressing issues of energy production and community wastewater treatment was using of Microbial Fuel Cells (MFCs). The objective of this research was to study the efficiency of electricity generation and community wastewater treatment of MFCs. This study used an experimental method completely randomized design (CRD), which consisted of two treatment factors (4×5 factorial design). The first factor was different solution containing organic matter (T) and consisting of 4 level factors including T1 (tap water), T2 (tap water with soil), T3 (50 % V/V community wastewater with soil), and T4 (100% community wastewater with soil). The second factor was the time (t), consisting of 5 level factors t1 (day 1), t2 (day 2), t3 (day 3), t4 (day 4), and t5 (day 5). There were 4 experimental models depending on containing organic matter (T1-T4). The parameter measured consisted of Open Circuit Voltage (OCV), Chemical Oxygen Demand (COD), Total Dissolve Solid (TDS), acidity (pH), Electric Conductivity (EC) and number of bacteria. Data were analysed by ANOVA, followed by Duncan test. The results of this study showed that, the T3 was the highest voltage at 0.816 V (P<0.05) and T4, T2, and Ti were 0.800, 0.797 and 0.747 V, respectively. The T3 was the lowest COD at 24.120 mg/L and T4 was 38.067 mg/L (P<0.05). The best model for electricity generation and community wastewater treatment by Microbial Fuel Cells was T3. This model generated highest voltage at 0.816 V, and reduction of COD at 46.215%.

Organic Pollutants in Shale Gas Flowback and Produced Waters: Identification, Potential Ecological Impact, and Implications for Treatment Strategies.

PubMed

Butkovskyi, Andrii; Bruning, Harry; Kools, Stefan A E; Rijnaarts, Huub H M; Van Wezel, Annemarie P

2017-05-02

Organic contaminants in shale gas flowback and produced water (FPW) are traditionally expressed as total organic carbon (TOC) or chemical oxygen demand (COD), though these parameters do not provide information on the toxicity and environmental fate of individual components. This review addresses identification of individual organic contaminants in FPW, and stresses the gaps in the knowledge on FPW composition that exist so far. Furthermore, the risk quotient approach was applied to predict the toxicity of the quantified organic compounds for fresh water organisms in recipient surface waters. This resulted in an identification of a number of FPW related organic compounds that are potentially harmful namely those compounds originating from shale formations (e.g., polycyclic aromatic hydrocarbons, phthalates), fracturing fluids (e.g., quaternary ammonium biocides, 2-butoxyethanol) and downhole transformations of organic compounds (e.g., carbon disulfide, halogenated organic compounds). Removal of these compounds by FPW treatment processes is reviewed and potential and efficient abatement strategies are defined.

Organic Pollutants in Shale Gas Flowback and Produced Waters: Identification, Potential Ecological Impact, and Implications for Treatment Strategies

PubMed Central

2017-01-01

Organic contaminants in shale gas flowback and produced water (FPW) are traditionally expressed as total organic carbon (TOC) or chemical oxygen demand (COD), though these parameters do not provide information on the toxicity and environmental fate of individual components. This review addresses identification of individual organic contaminants in FPW, and stresses the gaps in the knowledge on FPW composition that exist so far. Furthermore, the risk quotient approach was applied to predict the toxicity of the quantified organic compounds for fresh water organisms in recipient surface waters. This resulted in an identification of a number of FPW related organic compounds that are potentially harmful namely those compounds originating from shale formations (e.g., polycyclic aromatic hydrocarbons, phthalates), fracturing fluids (e.g., quaternary ammonium biocides, 2-butoxyethanol) and downhole transformations of organic compounds (e.g., carbon disulfide, halogenated organic compounds). Removal of these compounds by FPW treatment processes is reviewed and potential and efficient abatement strategies are defined. PMID:28376616

Anaerobic digestion of tuna waste for the production of volatile fatty acids.

PubMed

Bermúdez-Penabad, Noela; Kennes, Christian; Veiga, Maria C

2017-10-01

Fish canning industries generate a significant amount of solid waste that can be digested anaerobically into volatile fatty acids (VFA). The aim of this research was to study the effect of various pHs, ranging from 5.0 to 10.0, and percentage of total solids on the anaerobic digestion of tuna waste into VFA, both in batch assays and continuous reactor. The production of VFA was affected by pH and was significantly higher under alkaline conditions. At pH 8.0, the VFA production reached 30,611mgCOD/L. The VFA mainly consisted of acetic, propionic, n-butyric and i-valeric acids. Acetic acid was the main product at all the pHs tested. In terms of total solids (TS) the best results were obtained with 2.5% total solids, reaching 0.73gCOD VFA /gCOD waste . At higher TS concentrations (5 and 8% TS) lower yields were reached probably due to inhibition at high VFA concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of Bio-Amp, a commercial bio-additive for the treatment of grease trap wastewater containing fat, oil, and grease.

PubMed

Tang, Hao L; Xie, Yuefeng F; Chen, Yen-Chih

2012-11-01

This research investigated the application of Bio-Amp, a commercial bio-additive for the treatment of fat, oil, and grease (FOG) in a grease trap, and evaluated potential impacts of treated effluent on downstream collection system and treatment processes. Results show that after Bio-Amp treatment, FOG deposit formation was reduced by 40%, implicating a potential reduction of sewer line blockages. Chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and total fatty acids were reduced by 39%, 33%, 56%, and 59%, respectively, which represents an overall loading reduction of 9% COD, 5% TN and 40% TP received by the treatment plant from all the dining halls. On the other hand, readily biodegradable COD fractions significantly increased, which implies a potential improvement on Bio-P removal. Overall, the results showed that application of Bio-Amp in grease trap provides potential reduction of sewer line blockages, and can also alleviate downstream treatment burden. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Pathogen removal from domestic and swine wastewater by experimental constructed wetlands.

PubMed

Giácoman-Vallejos, G; Ponce-Caballero, C; Champagne, P

2015-01-01

This study examined the performance of subsurface flow horizontal wetlands in total coliforms, faecal coliforms, enterococci and Salmonella removal from swine and domestic wastewaters. The effects of organic loading rate, contact time (CT) and the presence of aquatic macrophytes, Typha dominguensis and Typha latifolia, on treatment performance were evaluated. In general, chemical oxygen demand (COD) and total suspended solids (TSS) were reduced by 66 and 72% after 24 h and 75 and 84% after 48 h in domestic wastewaters, and 73 and 71% after 24 h and 72 and 78% after 48 h in swine wastewater. Total coliform and faecal coliform reductions of 70-83% and 65-78% were observed in the vegetated systems after 24 h of CT, while after 48 h, total coliform and faecal coliform reductions of 80-82% and 86-91% were noted.

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.

Increasing the capacity for treatment of chemical plant wastewater by replacing existing suspended carrier media with Kaldnes Moving Bed media at a plant in Singapore.

PubMed

Wessman, F G; Yan Yuegen, E; Zheng, Q; He, G; Welander, T; Rusten, B

2004-01-01

The Kaldnes biomedia K1, which is used in the patented Kaldnes Moving Bed biofilm process, has been tested along with other types of biofilm carriers for biological pretreatment of a complex chemical industry wastewater. The main objective of the test was to find a biofilm carrier that could replace the existing suspended carrier media and at the same time increase the capacity of the existing roughing filter-activated sludge plant by 20% or more. At volumetric organic loads of 7.1 kg COD/m3/d the Kaldnes Moving Bed process achieved much higher removal rates and much lower effluent concentrations than roughing filters using other carriers. The Kaldnes roughing stage achieved more than 85% removal of organic carbon and more than 90% removal of BOD5 at the tested organic load, which was equivalent to a specific biofilm surface area load of 24 g COD/m2/d. Even for the combined roughing filter-activated sludge process, the Kaldnes carriers outperformed the other carriers, with 98% removal of organic carbon and 99.6% removal of BOD5. The Kaldnes train final effluent concentrations were only 22 mg FOC/L and 7 mg BOD5/L. Based on the successful pilot testing, the full-scale plant was upgraded with Kaldnes Moving Bed roughing filters. During normal operation the upgraded plant has easily met the discharge limits of 100 mg COD/L and 50 mg SS/L. For the month of September 2002, with organic loads between 100 and 115% of the design load for the second half of the month, average effluent concentrations were as low as 9 mg FOC/L, 51 mg COD/L and 12 mg SS/L.

Removal of non-biodegradable organic matter from landfill leachates by adsorption.

PubMed

Rodríguez, J; Castrillón, L; Marañón, E; Sastre, H; Fernández, E

2004-01-01

Leachates produced at the La Zoreda landfill in Asturias, Spain, were recirculated through a simulated landfill pilot plant. Prior to recirculation, three loads of different amounts of Municipal Solid Waste (MSW) were added to the plant, forming in this way consecutive layers. When anaerobic digestion was almost completed, the leachates from the landfill were recirculated. After recirculation, a new load of MSW was added and two new recirculations were carried out. The organic load of the three landfill leachates recirculated through the anaerobic pilot plant decreased from initial values of 5108, 3782 and 2560 mg/l to values of between 1500 and 1600 mg/l. Despite achieving reductions in the organic load of the leachate, a residual organic load still remained that was composed of non-biodegradable organic constituents such as humic substances. Similar values of the chemical oxygen demand (COD) were obtained when the landfill leachate was treated by a pressurised anoxic-aerobic process followed by ultrafiltration. After recirculation through the pilot plant, physico-chemical treatment was carried out to reduce the COD of the leachate. The pH of the leachate was decreased to a value of 1.5 to precipitate the humic fraction, obtaining a reduction in COD of about 13.5%. The supernatant liquid was treated with activated carbon and different resins, XAD-8, XAD-4 and IR-120. Activated carbon presented the highest adsorption capacities, obtaining COD values for the treated leachate in the order of 200mg/l. Similar results were obtained when treating with activated carbon, the leachate from the biological treatment plant at the La Zoreda landfill; in this case without decreasing the pH.

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.

High organic loading rate on thermophilic hydrogen production and metagenomic study at an anaerobic packed-bed reactor treating a residual liquid stream of a Brazilian biorefinery.

PubMed

Ferraz Júnior, Antônio Djalma Nunes; Etchebehere, Claudia; Zaiat, Marcelo

2015-06-01

This study evaluated the influence of a high organic loading rate (OLR) on thermophilic hydrogen production at an up-flow anaerobic packed-bed reactor (APBR) treating a residual liquid stream of a Brazilian biorefinery. The APBR, filled with low-density polyethylene, was operated at an OLR of 84.2 kg-COD m(-3) d(-1). This value was determined in a previous study. The maximum values of hydrogen production and yield were 5,252.6 mL-H2 d(-1) and 3.7 mol-H2 mol(-1)(total carbohydrates), respectively. However, whereas the OLR remained constant, the specific organic load rate (sOLR) decreased throughout operation from 1.38 to 0.72 g-Total carbohydratesg-VS(-1) h(-1), this decrease negatively affected hydrogen production. A sOLR of 0.98 g-Total carbohydratesg-VS(-1) h(-1) was optimal for hydrogen production. The microbial community was studied using 454-pyrosequencing analysis. Organisms belonging to the genera Caloramator, Clostridium, Megasphaera, Oxobacter, Thermoanaerobacterium, and Thermohydrogenium were detected in samples taken from the reactor at operation days 30 and 60, suggesting that these organisms contribute to hydrogen production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Treatment of high ethanol concentration wastewater by biological sand filters: enhanced COD removal and bacterial community dynamics.

PubMed

Rodriguez-Caballero, A; Ramond, J-B; Welz, P J; Cowan, D A; Odlare, M; Burton, S G

2012-10-30

Winery wastewater is characterized by its high chemical oxygen demand (COD), seasonal occurrence and variable composition, including periodic high ethanol concentrations. In addition, winery wastewater may contain insufficient inorganic nutrients for optimal biodegradation of organic constituents. Two pilot-scale biological sand filters (BSFs) were used to treat artificial wastewater: the first was amended with ethanol and the second with ethanol, inorganic nitrogen (N) and phosphorus (P). A number of biochemical parameters involved in the removal of pollutants through BSF systems were monitored, including effluent chemistry and bacterial community structures. The nutrient supplemented BSF showed efficient COD, N and P removal. Comparison of the COD removal efficiencies of the two BSFs showed that N and P addition enhanced COD removal efficiency by up to 16%. Molecular fingerprinting of BSF sediment samples using denaturing gradient gel electrophoresis (DGGE) showed that amendment with high concentrations of ethanol destabilized the microbial community structure, but that nutrient supplementation countered this effect. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fluorescence-based monitoring of tracer and substrate distribution in an UASB reactor.

PubMed

Lou, S J; Tartakovsky, B; Zeng, Y; Wu, P; Guiot, S R

2006-11-01

In this work, rhodamine-related fluorescence was measured on-line at four reactor heights in order to study hydrodynamics within an upflow anaerobic sludge bed reactor. A linear dependence of the dispersion coefficient (D) on the upflow velocity was observed, while the influence of the organic loading rate (OLR) was insignificant. Furthermore, the Bodenstein number of the reactor loaded with granulated sludge was found to be position-dependent with the largest values measured at the bottom of the sludge bed. This trend was not observed in the reactor without sludge. Chemical oxygen demand (COD) and volatile fatty acid (VFA) concentrations were measured at the same reactor heights as in rhodamine tests using conventional off-line analytical methods and on-line multiwavelength fluorometry. Significant spatial COD and VFA gradients were observed at organic loading rates above 6g COD l(R)(-1)d(-1) and linear upflow velocities below 0.8m h(-1).

The biofilm environment offers a possible condition for inducing the competency of DNA recipient cells through nutritional starvation.

PubMed

Nishioka, Motomu; Mashayekhan, Shohreh; Onishi, Kyoko; Taya, Masahito

2007-09-01

Transformation phenomena occurring under conditions mimicking the biofilm environment were investigated using Escherichia coli IM302 (as DNA recipient cells) and Providencia sp. WW2 (as surrounding cells in the biofilm model). In the case of planktonic IM302 cells kept at 25 degrees C, the transformation took place exclusively in the absence of organic nutrients (COD = 0), and was not substantially observed in the range of COD = 30-1500 mg O2/L. On the other hand, in the case of biofilm IM302 cells, the transformation occurred at relatively high levels under the examined conditions (temperature = 5 or 25 degrees C and COD = 0-1500 mg O2/L). These results indicated that the competency of biofilm IM302 cells was induced even in the presence of organic nutrients owing to nutritional starvation caused by WW2 cells.

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.

Non-biodegradable landfill leachate treatment by combined process of agitation, coagulation, SBR and filtration.

PubMed

Abood, Alkhafaji R; Bao, Jianguo; Du, Jiangkun; Zheng, Dan; Luo, Ye

2014-02-01

This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH3-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s(-1) within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD5) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L(-1) at pH 5.0. The biodegradable ratio BOD5/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD5, 95.5% COD and 98.1% NH3-N removal were achieved by SBR operated under anoxic-aerobic-anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD5, suspended solid (SS), NH3-N and total organic carbon (TOC) were 72.4 mg L(-1), 22.8 mg L(-1), 24.2 mg L(-1), 18.4 mg L(-1) and 50.8 mg L(-1) respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated pollutant loading from landfill leachate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Removal of organic matter and ammonium from landfill leachate through different scenarios: Operational cost evaluation in a full-scale case study of a Flemish landfill.

PubMed

Oloibiri, Violet; Chys, Michael; De Wandel, Stijn; Demeestere, Kristof; Van Hulle, Stijn W H

2017-12-01

Several scenarios are available to landfilling facilities to effectively treat leachate at the lowest possible cost. In this study, the performance of various leachate treatment sequences to remove COD and nitrogen from a leachate stream and the associated cost are presented. The results show that, to achieve 100% nitrogen removal, autotrophic nitrogen removal (ANR) or a combination of ANR and nitrification - denitrification (N-dN) is more cost effective than using only the N-dN process (0.58 €/m 3 ) without changing the leachate polishing costs associated with granular activated carbon (GAC). Treatment of N-dN effluent by ozonation or coagulation led to the reduction of the COD concentration by 10% and 59% respectively before GAC adsorption. This reduced GAC costs and subsequently reduced the overall treatment costs by 7% (ozonation) and 22% (coagulation). On the contrary, using Fenton oxidation to reduce the COD concentration of N-dN effluent by 63% increased the overall leachate treatment costs by 3%. Leachate treatment sequences employing ANR for nitrogen removal followed by ozonation or Fenton or coagulation for COD removal and final polishing with GAC are on average 33% cheaper than a sequence with N-dN + GAC only. When ANR is the preceding step and GAC the final step, choice of AOP i.e., ozonation or Fenton did not affect the total treatment costs which amounted to 1.43 (ozonation) and 1.42 €/m 3 (Fenton). In all the investigated leachate treatment trains, the sequence with ANR + coagulation + GAC is the most cost effective at 0.94 €/m 3 . Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Urechis unicinctus juveniles on chemical characteristics of organically contaminated coastal sediment

NASA Astrophysics Data System (ADS)

Kang, Kyoung Ho; Zhang, Zhifeng; Kim, Jae Min; Seon, Seung Chun; Shao, Mingyu

2010-03-01

Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics. We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus to improve the quality of organically contaminated coastal sediment. Sediment samples were collected from a site that was heavily contaminated with organic matter (Seonso) and two sites that were clean (Myo-do, Dolsan-do). Urechis juveniles, obtained by artificial fertilization and cultured in the laboratory, were introduced to the sediment (weight 3 kg, depth 10 cm) at a density of 500 individuals per aquarium (length 50 cm, width 35 cm, height 30 cm) (Experiment 1), or at densities ranging from 100 to 900 individuals per beaker (Experiment 2). To examine how sediment contamination can be modified by the effects of Urechis, 500 individuals (per aquarium) were exposed to the Seonso contaminated sediment that had been mixed with 0-100% clean sand (Experiment 3). Each experiment lasted two months and sediment samples were collected every 15 d to determine the several indexes of sediment quality, which included acid volatile sulfide (AVS), chemical oxygen demand (COD) and total ignition loss (TIL). In Experiment 1, the existence of Urechis did not result in significant changes in quality indexes in the sediments collected from Myo-do, Dolsan-do. However, AVS, COD and TIL of the Seonso sediment all decreased significantly after co-incubation with Urechis juveniles for 30 to 45 d. Experiment 2 showed that a density of at least 300 juveniles per beaker was necessary to significantly reduce all three quality indexes, and the magnitude of reduction was positively correlated with juvenile density. Experiment 3 revealed that Urechis juveniles were effective in reducing the AVS, COD and TIL of the Seonso sediment that had been mixed with 60%, 80%, and 80% of clean sand, respectively. The results of the present study therefore indicated that juveniles of this spoon worm have the potential to be used to improve the quality of organically contaminated sediment in coastal waters.

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.

Cold adaptation and replicable microbial community development during long-term low-temperature anaerobic digestion treatment of synthetic sewage

PubMed Central

Hughes, D; Mahony, T; Cysneiros, D; Ijaz, U Z; Smith, C J; O'Flaherty, V

2018-01-01

ABSTRACT The development and activity of a cold-adapting microbial community was monitored during low-temperature anaerobic digestion (LtAD) treatment of wastewater. Two replicate hybrid anaerobic sludge bed-fixed-film reactors treated a synthetic sewage wastewater at 12°C, at organic loading rates of 0.25–1.0 kg chemical oxygen demand (COD) m−3 d−1, over 889 days. The inoculum was obtained from a full-scale anaerobic digestion reactor, which was operated at 37°C. Both LtAD reactors readily degraded the influent with COD removal efficiencies regularly exceeding 78% for both the total and soluble COD fractions. The biomass from both reactors was sampled temporally and tested for activity against hydrolytic and methanogenic substrates at 12°C and 37°C. Data indicated that significantly enhanced low-temperature hydrolytic and methanogenic activity developed in both systems. For example, the hydrolysis rate constant (k) at 12°C had increased 20–30-fold by comparison to the inoculum by day 500. Substrate affinity also increased for hydrolytic substrates at low temperature. Next generation sequencing demonstrated that a shift in a community structure occurred over the trial, involving a 1-log-fold change in 25 SEQS (OTU-free approach) from the inoculum. Microbial community structure changes and process performance were replicable in the LtAD reactors. PMID:29846574

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.

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.

Cold adaptation and replicable microbial community development during long-term low-temperature anaerobic digestion treatment of synthetic sewage.

PubMed

Keating, C; Hughes, D; Mahony, T; Cysneiros, D; Ijaz, U Z; Smith, C J; O'Flaherty, V

2018-07-01

The development and activity of a cold-adapting microbial community was monitored during low-temperature anaerobic digestion (LtAD) treatment of wastewater. Two replicate hybrid anaerobic sludge bed-fixed-film reactors treated a synthetic sewage wastewater at 12°C, at organic loading rates of 0.25-1.0 kg chemical oxygen demand (COD) m-3 d-1, over 889 days. The inoculum was obtained from a full-scale anaerobic digestion reactor, which was operated at 37°C. Both LtAD reactors readily degraded the influent with COD removal efficiencies regularly exceeding 78% for both the total and soluble COD fractions. The biomass from both reactors was sampled temporally and tested for activity against hydrolytic and methanogenic substrates at 12°C and 37°C. Data indicated that significantly enhanced low-temperature hydrolytic and methanogenic activity developed in both systems. For example, the hydrolysis rate constant (k) at 12°C had increased 20-30-fold by comparison to the inoculum by day 500. Substrate affinity also increased for hydrolytic substrates at low temperature. Next generation sequencing demonstrated that a shift in a community structure occurred over the trial, involving a 1-log-fold change in 25 SEQS (OTU-free approach) from the inoculum. Microbial community structure changes and process performance were replicable in the LtAD reactors.

Integrated Evaluation of Urban Water Bodies for Pollution Abatement Based on Fuzzy Multicriteria Decision Approach.

PubMed

Hashim, Sarfraz; Yuebo, Xie; Saifullah, Muhammad; Nabi Jan, Ramila; Muhetaer, Adila

2015-01-01

Today's ecology is erected with miscellaneous framework. However, numerous sources deteriorate it, such as urban rivers that directly cause the environmental pollution. For chemical pollution abatement from urban water bodies, many techniques were introduced to rehabilitate the water quality of these water bodies. In this research, Bacterial Technology (BT) was applied to urban rivers escalating the necessity to control the water pollution in different places (Xuxi River (XXU); Gankeng River (GKS); Xia Zhang River (XZY); Fenghu and Song Yang Rivers (FSR); Jiu Haogang River (JHH)) in China. For data analysis, the physiochemical parameters such as temperature, chemical oxygen demand (COD), dissolved oxygen (DO), total phosphorus (TP), and ammonia nitrogen (NH3N) were determined before and after the treatment. Multicriteria Decision Making (MCDM) method was used for relative significance of different water quality on each station, based on fuzzy analytical hierarchy process (FAHP). The overall results revealed that the pollution is exceeding at "JHH" due to the limit of "COD" as critical water quality parameter and after treatment, an abrupt recovery of the rivers compared with the average improved efficiency of nutrients was 79%, 74%, 68%, and 70% of COD, DO, TP, and NH3N, respectively. The color of the river's water changed to its original form and aquatic living organism appeared with clear effluents from them.

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.

Effect of Organic Loading Rates on biodegradation of linear alkyl benzene sulfonate, oil and grease in greywater by Integrated Fixed-film Activated Sludge (IFAS).

PubMed

Eslami, Hadi; Ehrampoush, Mohammad Hassan; Ghaneian, Mohammad Taghi; Mokhtari, Mehdi; Ebrahimi, Aliasghar

2017-05-15

In this study, performance of Integrated Fixed-film Activated Sludge (IFAS) system in treatment of Linear Alkylbenzene Sulfonate (LAS), and oil & grease in synthetic greywater and effect of Organic Loading Rates (OLRs) on removal efficiency within a period of 105 days were investigated. Present study was carried out in a pilot scale under such conditions as temperature of 30 ± 1 °C, dissolved oxygen of 2.32 ± 0.91 mg/l, pH of 8.01 ± 0.95 and OLRs of 0.11-1.3gCOD/L.d. Also, Scanning Electron Microscopy (SEM) images were employed to specify rate of the biofilm formed on the media inside the reactor IFAS. The best removal efficiency for COD, LAS and oil and grease were respectively obtained as 92.52%, 94.24% and 90.07% in OLR 0.44gCOD/L.d. The assessment of loading rate indicated that with increased OLR to 0.44gCOD/L.d, removal efficiency of COD, oil and grease was increased while with increased OLR, removal efficiency was decreased. In doing so, based on the statistical test ANOVA, such a difference between removal efficiencies in diverse OLRs was significant for COD (p = 0.003), oil and grease (p = 0.01). However, in terms of LAS, with increased value of OLR to 0.44gCOD/L.d, the removal efficiency was increased and then with higher OLRs, removal efficiency was slightly decreased that is insignificant (p = 0.35) based on the statistical test ANOVA. The SEM images also showed that the biofilm formed on the media inside IFAS reactor plays a considerable role in adsorption and biodegradation of LAS, and oil & grease in greywater. The linear relation between inlet COD values and rate of removed LAS indicated that the ratio of inlet COD (mg/L) to removed LAS (mg/L) was 0.4. Therefore, use of IFAS system for biodegradation of LAS, oil and grease in greywater can be an applicable option. Copyright © 2017 Elsevier Ltd. 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.

Effect of organic loading rate on anaerobic co-digestion of rice straw and pig manure with or without biological pretreatment.

PubMed

Shen, Fei; Li, Hanguang; Wu, Xiaoyu; Wang, Yuanxiu; Zhang, Qinghua

2018-02-01

In this study, rice straw (RS) and pig manure (PM) mixtures with or without bio-pretreatment were used as the substrates and digested in a 9 L of anaerobic reactor at Organic loading rates (OLRs) of 0.4-3.1 kg COD/(m 3  d). The volumetric methane production rate (VMPR), methane yield and anaerobic stability were comparatively investigated. The results showed the co-anaerobic digestion processes of RS and PM mixture after biological pretreatment were very stable at OLRs of 0.4-2.5 kg COD/(m 3  d), and its optimal VMPR and methane yield could reach 0.64 L CH 4 /(L d) and 0.4557 L CH 4 /g COD removed at OLR of 2.5 kg COD/(m 3  d), which were 62.4% and 37.8% higher than those of the control under the same OLR condition. This study indicated the biological pretreatment with a cellulolytic microbial consortium own great potential in improving the methane yield and productivity of RS and PM wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Comparison of semi-batch vs. continuously fed anaerobic bioreactors for the treatment of a high-strength, solids-rich pumpkin-processing wastewater.

PubMed

del Agua, Isabel; Usack, Joseph G; Angenent, Largus T

2015-01-01

The objective of this work was to compare two different high-rate anaerobic bioreactor configurations--the anaerobic sequencing batch reactor (ASBR) and the upflow anaerobic solid removal (UASR) reactor--for the treatment of a solid-rich organic wastewater with a high strength. The two, 4.5-L reactors were operated in parallel for close to 100 days under mesophilic conditions (37°C) with non-granular biomass by feeding a pumpkin wastewater with ∼4% solids. The organic loading rate of pumpkin wastewater was increased periodically to a maximum of 8 g COD L(-1) d(-1) by shortening the hydraulic retention time to 5.3 days. Compositional analysis of pumpkin wastewater revealed deficiencies in the trace metal cobalt and alkalinity. With supplementation, the ASBR outperformed the UASR reactor with total chemical oxygen demand (COD) removal efficiencies of 64% and 53%, respectively, achieving a methane yield of 0.27 and 0.20 L CH4 g(-1) COD fed to the ASBR and UASR, respectively. The better performance realized with the ASBR and this specific wastewater was attributed to its semi-batch, dynamic operating conditions rather than the continuous operating conditions of the UASR reactor.

Research of combined adsorption-coagulation process in treating petroleum refinery effluent.

PubMed

Wang, Bing; Shui, Yiyu; Ren, Hongyang; He, Min

2017-02-01

The petroleum refinery industry generates a significant amount of wastewater that contains a high level of organic matter, which calls for effective and costly treatments. In this research, the effectiveness of the petroleum refinery effluent (PRE) treatment with physicochemical process of combined adsorption and coagulation was evaluated. The effects of initial pH, hydraulic condition , and combined sequence of treatment process, different treating reagent types and dosages on the chemical oxygen demand (COD) removal were investigated. Additionally, the elimination efficiency of pollutant wastewater was monitored by gas chromatography-mass spectrometry (GC-MS), and Fourier transformed infrared (FT-IR) spectrophotometer was adopted to describe the structure of the wastewater. Wooden activated carbon was chosen as adsorbent at the dosage of 10 g/L as a primary treatment, and 1500 mg/L polymeric magnesium ferric sulfate was used in coagulation. Results showed that adsorption and subsequent coagulation displayed the best performance when initial pH was 9 at shear rates (G) of G1 = 65 s -1 and G2 = 20 s -1 , which reached maximal removal rate of COD and total organic carbon GC-MS testing result revealed that adsorption was effective in phenols and iso-alkanes removal, whereas coagulation was good at removing esters and n-alkanes.

Nitrogen removal from landfill leachate via ex situ nitrification and sequential in situ denitrification

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

Zhong Qi; Graduate School of Chinese Academy of Sciences, Beijing 100049; Li Daping

2009-04-15

Ex situ nitrification and sequential in situ denitrification represents a novel approach to nitrogen management at landfills. Simultaneous ammonia and organics removal was achieved in a continuous stirred tank reactor (CSTR). The results showed that the maximum nitrogen loading rate (NLR) and the maximum organic loading rate (OLR) was 0.65 g N l{sup -1} d{sup -1} and 3.84 g COD l{sup -1} d{sup -1}, respectively. The ammonia and chemical oxygen demand (COD) removal was over 99% and 57%, respectively. In the run of the CSTR, free ammonia (FA) inhibition and low dissolved oxygen (DO) were found to be key factorsmore » affecting nitrite accumulation. In situ denitrification was studied in a municipal solid waste (MSW) column by recalculating nitrified leachate from CSTR. The decomposition of MSW was accelerated by the recirculation of nitrified leachate. Complete reduction of total oxidized nitrogen (TON) was obtained with maximum TON loading of 28.6 g N t{sup -1} TS d{sup -1} and denitrification was the main reaction responsible. Additionally, methanogenesis inhibition was observed while TON loading was over 11.4 g N t{sup -1} TS d{sup -1} and the inhibition was enhanced with the increase of TON loading.« less

Electrochemical treatment of cork boiling wastewater with a boron-doped diamond anode.

PubMed

Fernandes, Annabel; Santos, Diana; Pacheco, Maria José; Ciríaco, Lurdes; Simões, Rogério; Gomes, Arlindo C; Lopes, Ana

2015-01-01

Anodic oxidation at a boron-doped diamond anode of cork boiling wastewater was successfully used for mineralization and biodegradability enhancement required for effluent discharge or subsequent biological treatment, respectively. The influence of the applied current density (30-70 mA/cm2) and the background electrolyte concentration (0-1.5 g/L Na2SO4) on the performance of the electrochemical oxidation was investigated. The supporting electrolyte was required to achieve conductivities that enabled anodic oxidation at the highest current intensities applied. The results indicated that pollutant removal increased with the applied current density, and after 8 h, reductions greater than 90% were achieved for COD, dissolved organic carbon, total phenols and colour. The biodegradability enhancement was from 0.13 to 0.59 and from 0.23 to 0.72 for the BOD/COD ratios with BOD of 5 and 20 days' incubation period, respectively. The tests without added electrolyte were performed at lower applied electrical charges (15 mA/cm2 or 30 V) with good organic load removal (up to 80%). For an applied current density of 30 mA/cm2, there was a minimum of electric conductivity of 1.9 mS/cm (corresponding to 0.75 g/L of Na2SO4), which minimized the specific energy consumption.

The use of Fenton's system in the yeast industry wastewater treatment.

PubMed

Zak, S

2005-01-01

The paper presents the results of the research conducted with the use of hydrogen peroxide and iron (II) sulfate or chloride in the chemical pretreatment of Saccharomyces cerevisae yeast industry wastewater. It was found that the use of Fenton's system permitted a high reduction of sugar-like substances and total decolorizing of non-sugar compounds. The level of COD reduction depended on the amount and mutual proportions of COD:Fe(II):H2O2, as well as a type of the applied salt Fe(II). For iron concentrations: 1000-4000 mg l(-1) with molar excess [H2O2]:[Fe(II)] - 2-14:1 and reaction pH - 3.1-3.4, very high reproducibility of results and the COD reduction exceeding 75% were obtained. For this range of the reagent concentrations, the distribution of COD reduction values correlated with the equation: COD = - Ax4 + Bx3 - Cx2 + Dx - E (where: x = [H2O2]:[Fe(II)]). Additional neutralization with the use of lime milk made the secondary reduction of CODr(CaO) value possible, which resulted in the reduction of the total CODT above 90%. The method enabled us to consider the possibility of the preliminary chemical elimination of the wastewater load, which might increase the effectiveness of working wastewater treatment plants, especially in cases of continuous and occasional overloads above the level assumed by the project.

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.

Effect of the length of the cycle on biodegradable polymer production and microbial community selection in a sequencing batch reactor.

PubMed

Dionisi, Davide; Majone, Mauro; Vallini, Giovanni; Gregorio, Simona Di; Beccari, Mario

2007-01-01

The effect of the length of the cycle on the enrichment and selection of mixed cultures in sequencing batch reactors (SBRs) has been studied, with the aim of biodegradable polymers (namely, polyhydroxyalkanoates (PHAs)) production from organic wastes. At a fixed feed concentration (20 gCOD/L) and organic loading rate (20 gCOD/L/day), the SBR was operated at different lengths of the cycle, in the range 1-8 h. Process performance was measured by considering the rates and yields of polymer storage and of the competing phenomenon of growth. The selected biomass was enriched with microorganisms that were able to store PHAs at high rates and yields only when the length of the cycle was 2 or 4 h, even though in these conditions the process was unstable. On the other hand, when the length of the cycle was 1 or 8 h, the dynamic response of the selected microorganisms was dominated by growth. The best process performance was characterized by storage rates in the range 500-600 mgCOD/gCOD/h and storage yields of 0.45-0.55 COD/COD. The corresponding productivity of the process was in the range 0.25-0.30 gPHA/L/h, the highest values obtained until now for mixed cultures. The microbial composition of the selected biomasses was analyzed through denaturing gradient gel electrophoresis (DGGE) and reverse-transcriptase denaturing gradient gel electrophoresis (RT-DGGE). The instability of the runs characterized by high storage rate was associated with a higher microbial heterogeneity compared to the runs with a stable growth response.

75 FR 55690 - Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pacific cod in the Bering...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-14

.... 0910131363-0087-02] RIN 0648-XZ01 Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pacific cod in the Bering Sea and Aleutian Islands Management Area AGENCY: National Marine Fisheries... Sea and Aleutian Islands management area. These actions are necessary to allow the 2010 total...

Temperature-Dependent Lipid Storage of Juvenile Arctic cod (Boreogadus saida) and Co-Occurring North Pacific Gadids

NASA Astrophysics Data System (ADS)

Copeman, L.; Laurel, B.; Spencer, M. L.; Iseri, P.; Sremba, A. L.

2016-02-01

Climate change impacts on Arctic ecosystems will largely be determined by temperature-dependent bioenergetics of resident and invading forage fish species. In this study, we experimentally measured total lipids and lipid class storage in the liver and muscle of juvenile Arctic gadids (Arctic cod, Boreogadus saida and saffron cod, Eleginus gracilis) and two North Pacific gadids (walleye pollock, Gadus chalcogrammus and Pacific cod, Gadus macrocephalus). Experiments were conducted over a 6-wk period across five temperatures (0, 5, 9, 16 and 20 °C) at the Hatfield Marine Science Center in Newport, OR, USA. Results indicated clear physiological differences among species in terms of temperature-dependent growth and lipid storage. Arctic cod exhibited highest growth and lipid storage (27 mg/g WW) at the coldest temperature (0 °C) compared to the other gadids, with near maximum growth at 5 °C and onset of mortality above 9 °C. In contrast, saffron cod growth rates steadily increased at temperatures beyond 16 °C, but lipid storage was low overall with only slightly higher lipid storage at warm temperatures (10 to 17 mg/g WW). Both walleye pollock and Pacific cod showed a domed response with increased lipid storage and growth at intermediate temperatures (9 - 12°C) and reduced growth and lipid storage at cold and warm maxima. We did not observe a trade-off between growth rate and lipid accumulation in any species. These results suggest that saffron cod can thrive in a warming Arctic but will be energetically inferior as a prey item to the more temperature-sensitive Arctic cod. Alternatively, North Pacific gadids can energetically resemble Arctic cod at warmer temperatures and could theoretically be an important prey item if their range extends northward with continued climate change.

Seasonal and annual variation in the diet of Atlantic cod (Gadus morhua) in relation to the abundance of capelin (Mallotus villosus) off eastern Newfoundland, Canada

USGS Publications Warehouse

Methven, David A.; Piatt, John F.

1989-01-01

The importance of capelin as prey for cod has long been known (Thompson, 1943; and see Lilly (1987) for a review); however, no studies have been conducted on how the highly dynamic seasonal and yearly variations in capelin abundance affect cod diet. We studied the occurrence of capelin in cod stomachs in relation to the relative abundance of capelin at Witless Bay, Newfoundland (47°15’N 52°46’W), during June, July and August, 1982-1984. The mean number of capelin per stomach and the per cent occurrence of stomachs containing capelin were determined for each collection of stomachs. A total of 680 stomachs were examined. Cod were sampled from those caught in gillnets by fishermen and averaged 66 cm ± 8 (s.d.) in 1983 and 62 cm ± 8 (s.d.) in 1984. Relative abundance of capelin in the local habitat was determined by conducting hydroacoustic surveys around Gull Island in Witless Bay, the same area where cod were collected for stomach content analysis. Only hydroacoustic surveys conducted within three days of cod stomach collections were analyzed. Further details of hydroacoustic surveys including quantifications of acoustic echograms are described in Piatt (1989).

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.

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.

An evaluation of the phosphorus storage capacity of an anaerobic/aerobic sequential batch biofilm reactor.

PubMed

Chiou, Ren-Jie; Yang, Yi-Rong

2008-07-01

The aim of this work was to assess the phosphorus storage capability of the polyphosphate (poly-P) accumulating organisms (PAO) in the biofilm using a sequential batch biofilm reactor (SBBR). In the anaerobic phase, the specific COD uptake rates increases from 0.05 to 0.22 (mg-COD/mg-biomass/h) as the initial COD increases and the main COD uptake activity occurs in the initial 30 min. The polyhydroxyalkanoates (PHAs) accumulation from 18 to 38 (mg-PHA/g-biomass) and phosphorus release from 20 to 60 (mg-P/L) share a similar trend. The adsorbed COD cannot be immediately transformed to PHAs. Since the PHAs' demand per released phosphorus is independent of the initial COD, the enhancement of the PHA accumulation would be of benefit to phosphorus release. The only requirement is to have an initial amount of substrate that will result in sufficient PHA accumulation (approximately 20 mg-PHA/g-biomass) for phosphorus release. During the aerobic phase, the aeration should not only provide sufficient dissolved oxygen, but should also enhance the mass transfer and the diffusion. In other words, the limitation to the phosphorus storage capability always occurs during the anaerobic phase, not the aerobic phase.

Simulated responses of streams and ponds to groundwater withdrawals and wastewater return flows in southeastern Massachusetts

USGS Publications Warehouse

Carlson, Carl S.; Walter, Donald A.; Barbaro, Jeffrey R.

2015-12-21

The percentages of the total number of ponds affected by pumping with wastewater return flows under long-term average conditions in the modeled areas were 28 percent for the Plymouth-Carver region, 67 percent for western Cape Cod, and 75 percent for eastern Cape Cod. Pond-level alterations ranged from a decrease of 4.6 feet at Great South Pond in the Plymouth Carver region to an increase of 0.9 feet at Wequaquet Lake in western Cape Cod. The magnitudes of monthly alterations to pond water levels were fairly consistent throughout the year.

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.

Carbon and energy footprint of electrochemical vinegar wastewater treatment

NASA Astrophysics Data System (ADS)

Gerek, Emine Esra; Yilmaz, Seval; Savaş Koparal, A.; Nezih Gerek, Ömer

2017-11-01

Electrochemical treatment of wastewaters that are rich in organic compounds is a popular method, due to its acidic nature that avoids biological treatment. In many cases, the pollution hazard is considered as the chemical oxygen demand (COD) from active carbon, and the success of the treatment is measured in terms of how much this specific parameter is reduced. However, if electricity is used during the treatment process, the treatment "itself" has manufacturing and operational energy costs. Many of the studies consider energy utilization as a monetary cost, and try to reduce its amount. However, the energy cost of the treatment also causes emission of carbon at the energy producing side of the closed loop. This carbon emission can be converted into oxygen demand, too. Therefore, it can be argued that one must look for the total optimal carbon efficiency (or oxygen demand), while reducing the COD. We chose a highly acidic wastewater case of vinegar production, which is a popular food product in Turkey, to demonstrate the high energy consumption and carbon emission problem of the electrochemical treatment approach. A novel strategy is presented to monitor total oxygen demand simultaneously at the treatment and energy production sides. Necessity of renewable energy utilization and conditions on process termination points are discussed.

Physical-chemical characterization of the textile dye Azo Ab52 degradation by corona plasma

NASA Astrophysics Data System (ADS)

Gómez, A.; Torres-Arenas, A. J.; Vergara-Sánchez, J.; Torres, C.; Reyes, P. G.; Martínez, H.; Saldarriaga-Noreña, Hugo

2017-10-01

This work characterizes the degradation of the textile dye azo Acid Black 52 by measuring several physical and chemical parameters. A corona plasma was created at atmospheric pressure and applied on the liquid-air interface of water samples containing the dye. 1.0 mM of ferrous sulfate (FeSO4) was added to 1.0 mM dye solution, for a total volume of 250 mL. For each treatment, a number of parameters were quantified. These were voltage, current, temperature, loss of volume, pH, electrical conductivity, concentration, optical mission spectra, chemical oxygen demand (COD), total organic carbon (TOC), and the removal ratio. Because of the increase in the sample temperature, the volume lost by evaporation was explored. The results show that the efficiency of the dye degradation by plasma is a function of treatment time. Moreover, the reactive concentration of FeSO4 and the exposition time of the plasma were varied at a constant volume, leading to the determination of the concentrations and optimal times. Considering the degradation and removal parameters, at the maximum treated time of 80 min, it found that COD was of 96.36%, TOC of 93.93%, and the removal ratio of 97.47%.

Drawer compacted sand filter: a new and innovative method for on-site grey water treatment.

PubMed

Assayed, Almoayied; Chenoweth, Jonathan; Pedley, Steven

2014-01-01

In this paper, results ofa new sand filter design were presented. The drawer compacted sand filter (DCSF) is a modified design for a sand filter in which the sand layer is broken down into several layers, each of which is 10 cm high and placed in a movable drawer separated by a 10 cm space. A lab-scale DCSF was designed and operated for 330 days fed by synthetic grey water. The response of drawer sand filters to variable hydraulic and organic loading rates (HLR and OLR) in terms of biological oxygen demand (BODs), chemical oxygen demand (COD), total suspended solids (TSS), pH, electrical conductivity and Escherichia coli reductions were evaluated. The HLR was studied by increasing from 72 to 142 L m(-2) day(-1) and OLR was studied by increasing it from 23 to 30 g BOD5 m(-2) day(-1) while keeping the HLR constant at 142 L m(-2) day(-1). Each loading regime was applied for 110 days. Results showed that DCSF was able to remove >90% of organic matter and total suspended solids for all doses. No significant difference was noticed in terms of overall filter efficiency between different loads for all parameters. Significant reduction in BOD5 and COD (P < .05) was noticed after water was drained through the third drawer in all tested loads. The paper concludes that DCSF would be appropriate for use in dense urban areas as its footprint is small and is appropriate for a wide range of users because of its convenience and low maintenance requirements.

Synthetic olive mill wastewater treatment by Fenton's process in batch and continuous reactors operation.

PubMed

Esteves, Bruno M; Rodrigues, Carmen S D; Madeira, Luís M

2017-11-04

Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused on the optimization of key operational parameters of the Fenton process in a batch reactor, namely Fe 2+ dosage, hydrogen peroxide concentration, pH, and reaction temperature. On the assessment of the process efficiency, > 99% of TPh and > 56% of TOC removal were attained when [Fe 2+ ] = 100 ppm, [H 2 O 2 ] = 2.0 g/L, T = 30 °C, and initial pH = 5.0, after 300 min of reaction. Under those operational conditions, experiments on a continuous stirred-tank reactor (CSTR) were performed for different space-time values (τ). TOC and TPh removals of 47.5 and 96.9%, respectively, were reached at steady-state (for τ = 120 min). High removal of COD (> 75%) and BOD 5 (> 70%) was achieved for both batch and CSTR optimum conditions; analysis of the BOD 5 /COD ratio also revealed an increase in the effluent's biodegradability. Despite the high removal of lumped parameters, the treated effluent did not met the Portuguese legal limits for direct discharge of wastewaters into water bodies, which indicates that coupled chemical-biological process may be the best solution for real olive mill wastewater treatment.

Discoloration and detoxicification of a Congo red dye solution by means of ozone treatment for a possible water reuse.

PubMed

Khadhraoui, M; Trabelsi, H; Ksibi, M; Bouguerra, S; Elleuch, B

2009-01-30

The objective of this study was to investigate the degradation and mineralization of an azo-dye, the Congo red, in aqueous solutions using ozone. Phytotoxicity and the inhibitory effects on the microbial activity of the raw and the ozonated solutions were also carried out with the aim of water reuse and environment protection. Decolorization of the aqueous solutions, disappearance of the parent compound, chemical oxygen demand (COD) and total organic carbon (TOC) removal were the main parameters monitored in this study. To control the mineralization of the Congo red, pH of the ozonated solution and heteroatoms released from the mother molecule such NH(4)(+), NO(3)(-) and SO(4)(2-) were determined. It was concluded that ozone by itself is strong enough to decolorize these aqueous solutions in the early stage of the oxidation process. Nonetheless, efficient mineralization had not been achieved. Significant drops in COD (54%) were registered. The extent of TOC removal was about 32%. Sulfur heteroatom was totally oxidized to SO(4)(2-) ions while the central -NN- azo ring was partially converted to NH(4)(+) and NO(3)(-). Results of the kinetic studies showed that ozonation of the selected molecule was a pseudo-first-order reaction with respect to dye concentration. The obtained results also demonstrate that ozone process reduced the phytotoxicity of the raw solution and enhanced the biodegradability of the treated azo-dyes-wastewater. Hence, this show that ozone remains one of the effective technologies for the discoloration and the detoxification of organic dyes in wastewater.

Biogas Production from Brewer’s Yeast Using an Anaerobic Sequencing Batch Reactor

PubMed Central

2017-01-01

Summary Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer’s yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer’s yeast is higher than its energy value. Due to the increase of energy prices, brewer’s yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer’s yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR) seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m3·day), and with a maximum achieved organic loading rate of 13.6 kg/(m3·day) in a single cycle. A specific biogas productivity of over 0.430 m3/kg of the total chemical oxygen demand (COD) inserted, and total COD removal efficiencies of over 90% were achieved. This study suggests that the brewer’s yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer’s yeast/wastewater mixtures of up to 8% (by volume). By using the brewer’s yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50%. PMID:28867948

Evaluation of the potential for operating carbon neutral WWTPs in China.

PubMed

Hao, Xiaodi; Liu, Ranbin; Huang, Xin

2015-12-15

Carbon neutrality is starting to become a hot topic for wastewater treatment plants (WWTPs) all over the world, and carbon neutral operations have emerged in some WWTPs. Although China is still struggling to control its water pollution, carbon neutrality will definitely become a top priority for WWTPs in the near future. In this review, the potential for operating carbon neutral WWTPs in China is technically evaluated. Based on the A(2)/O process of a typical municipal WWTP, an evaluation model is first configured, which couples the COD/nutrient removals (mass balance) with the energy consumption/recovery (energy balance). This model is then applied to evaluate the potential of the organic (COD) energy with regards to carbon neutrality. The model's calculations reveal that anaerobic digestion of excess sludge can only provide some 50% of the total amount of energy consumption. Water source heat pumps (WSHP) can effectively convert the thermal energy contained in wastewater to heat WWTPs and neighbourhood buildings, which can supply a net electrical equivalency of 0.26 kWh when 1 m(3) of the effluent is cooled down by 1 °C. Photovoltaic (PV) technology can generate a limited amount of electricity, barely 10% of the total energy consumption. Moreover, the complexity of installing solar panels on top of tanks makes PV technology almost not worth the effort. Overall, therefore, organic and thermal energy sources can effectively supply enough electrical equivalency for China to approach to its target with regards to carbon neutral operations. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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.

Sequencing batch reactor biofilm system for treatment of milk industry wastewater.

PubMed

Sirianuntapiboon, Suntud; Jeeyachok, Narumon; Larplai, Rarintorn

2005-07-01

A sequencing batch reactor biofilm (MSBR) system was modified from the conventional sequencing batch reactor (SBR) system by installing 2.7 m2 surface area of plastic media on the bottom of the reactor to increase the system efficiency and bio-sludge quality by increasing the bio-sludge in the system. The COD, BOD5, total kjeldahl nitrogen (TKN) and oil & grease removal efficiencies of the MSBR system, under a high organic loading of 1340 g BOD5/m3 d, were 89.3+/-0.1, 83.0+/-0.2, 59.4+/-0.8, and 82.4+/-0.4%, respectively, while they were only 87.0+/-0.2, 79.9+/-0.3, 48.7+/-1.7 and 79.3+/-10%, respectively, in the conventional SBR system. The amount of excess bio-sludge in the MSBR system was about 3 times lower than that in the conventional SBR system. The sludge volume index (SVI) of the MSBR system was lower than 100 ml/g under an organic loading of up to 1340 g BOD5/m3 d. However, the MSBR under an organic loading of 680 g BOD5/m3 d gave the highest COD, BOD5, TKN and oil & grease removal efficiencies of 97.9+/-0.0, 97.9+/-0.1, 79.3+/-1.0 and 94.8+/-0.5%, respectively, without any excess bio-sludge waste. The SVI of suspended bio-sludge in the MSBR system was only 44+/-3.4 ml/g under an organic loading of 680 g BOD5/m3 d.

Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

PubMed Central

Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

2011-01-01

This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility.

PubMed

Wong, Del P; Chaouachi, Anis; Lau, Patrick W C; Behm, David G

2011-01-01

This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key pointsThe duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001).No significant differences in RSA and COD between the 3 stretching conditions.The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects.The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments.

Potential of organic filter materials for treating greywater to achieve irrigation quality: a review.

PubMed

Dalahmeh, Sahar S; Hylander, Lars D; Vinnerås, Björn; Pell, Mikael; Oborn, Ingrid; Jönsson, Håkan

2011-01-01

The objectives of this literature review were to: (i) evaluate the impact of greywater generated in rural communities, with the emphasis on Jordanian conditions, on soil, plant and public health and assess the need for treatment of this greywater before it is used for irrigation, and (ii) assess the potential of different types of organic by-products as carrier material in different filter units for removal of pollutants from greywater. Greywater with high BOD5, COD, high concentrations of SS, fat, oil and grease and high levels of surfactants is commonly found in rural areas in Jordan. Oxygen depletion, odour emission, hydrophobic soil phenomena, plant toxicity, blockage of piping systems and microbiological health risks are common problems associated with greywater without previous treatment. Organic by-products such as wood chips, bark, peat, wheat straw and corncob may be used as carrier material in so-called mulch filters for treating wastewater and greywater from different sources. A down-flow-mode vertical filter is a common setup used in mulch filters. Wastewaters with a wide range of SS, cBOD5 and COD fed into different mulch filters have been studied. The different mulch materials achieved SS removal ranging between 51 and 91%, a BOD5 reduction range of 55-99.9%, and COD removal of 51-98%. Most types of mulches achieved a higher organic matter removal than that achieved by an ordinary septic tank. Bark, peat and wood chips filters removed organic matter better than sand and trickling filters, under similar conditions. Release of filter material and increase in COD in the effluent was reported using some mulch materials. In conclusion, some mulch materials such as bark, peat and woodchips seem to have a great potential for treatment of greywater in robust, low-tech systems. They can be expected to be resilient in dealing with variable low and high organic loads and shock loads.

Shelf-life extension of cod fillets with an acetate buffer spray prior to packaging under modified atmospheres.

PubMed

Boskou, G; Debevere, J

2000-01-01

Fresh cod fillets (Gadus morhua) were sprayed with a 10% acetate buffer (pH 5.6), packed with an industrial gas-flushing packaging machine under modified atmospheres (50% CO2--45% O2--5% N2, 2 cm3/1 g gas/product ratio) and stored at 7 degrees C for 12 days. Control cod fillets were directly packed and stored under the same conditions. A reduction of the aerobic plate counts was observed immediately after the cod fillets had been sprayed. During storage under modified atmospheres, there was complete inhibition of H2S-producing bacteria and Enterobacteriaceae in the treated cod fillets. Production of total volatile bases and trimethylamine (TMA) was inhibited in treated fillets for 10 days' storage under modified atmospheres. Inhibition of TMA production can be attributed to growth inhibition of H2S-producing bacteria, inhibition of the trimethylamine oxide (TMAO)-dependent metabolism of TMAO-reducing bacteria and the stable pH during storage. The shelf-life, at 7 degrees C, of treated cod fillets, based on cooked flavour score, was almost 12 days, ca 8 days more than shelf-life of the control fillets.

Combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes and activated carbon bioreactor for oilfield wastewater treatment.

PubMed

Guo, Chunmei; Chen, Yi; Chen, Jinfu; Wang, Xiaojun; Zhang, Guangqing; Wang, Jingxiu; Cui, Wenfeng; Zhang, Zhongzhi

2014-10-01

This paper investigated the enhancement of the COD reduction of an oilfield wastewater treatment process by installing air-lift tubes and adding an activated carbon bioreactor (ACB) to form a combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes (HA/air-lift BCO) and an ACB. Three heat-resistant bacterial strains were cultivated and subsequently applied in above pilot plant test. Installing air-lift tubes in aerobic tanks reduced the necessary air to water ratio from 20 to 5. Continuous operation of the HA/air-lift BCO system for 2 months with a hydraulic retention time of 36 h, a volumetric load of 0.14 kg COD/(m(3)d) (hydrolysis-acidification or anaerobic tank), and 0.06 kg COD/(m(3)d) (aerobic tanks) achieved an average reduction of COD by 60%, oil and grease by 62%, total suspended solids by 75%, and sulfides by 77%. With a COD load of 0.56 kg/(m(3)d), the average COD in the ACB effluent was 58 mg/L. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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%.

Incremental sanitation improvement strategy: comparison of options for Hanoi, Vietnam.

PubMed

Harada, H; Matsui, S; Dong, N T; Shimizu, Y; Fujii, S

2010-01-01

Urban sanitation issues should be tackled strategically, and may be addressed effectively when sewage development is pursued in conjunction with complementary sanitation measures. Five sanitation improvement scenarios employing sewage, night-soil collection-and-treatment (NSCT) system, and/or septic-tank improvement by annual dislodging were analyzed from the perspective of COD loads, total nitrogen loads, and cost under the conditions found in Hanoi, Vietnam. Compared to the development of sewage alone, the scenario of developing NSCT systems in a complementary manner with sewage development was estimated to be the most effective for a rapid decrease of both COD and total nitrogen loads. However, it may be difficult in some cases to replace ordinary water-flush toilet by the micro-flush toilet that are used in NSCT systems. In this case, the scenario employing septic-tank improvement in conjunction with sewage development may be effective for a rapid decrease of COD in locations where septic tanks are widely used under poor maintenance conditions and nitrogen pollution is not serious compared to COD. It was calculated that the two scenarios above would respectively require cost increases of 16 and 22% over the sewage development scenario.

Process contribution evaluation for COD removal and energy production from molasses wastewater in a BioH2-BioCH4-MFC-integrated system.

PubMed

Yun, Jeonghee; Lee, Yun-Yeong; Choi, Hyung Joo; Cho, Kyung-Suk

2017-01-01

In this study, a three-stage-integrated process using the hydrogenic process (BioH 2 ), methanogenic process (BioCH 4 ), and a microbial fuel cell (MFC) was operated using molasses wastewater. The contribution of individual processes to chemical oxygen demand (COD) removal and energy production was evaluated. The three-stage integration system was operated at molasses of 20 g-COD L -1 , and each process achieved hydrogen production rate of 1.1 ± 0.24 L-H 2 L -1 day -1 , methane production rate of 311 ± 18.94 mL-CH 4 L -1 day -1 , and production rate per electrode surface area of 10.8 ± 1.4 g m -2 day -1 . The three-stage integration system generated energy production of 32.32 kJ g-COD -1 and achieved COD removal of 98 %. The contribution of BioH 2 , BioCH 4 , and the MFC reactor was 20.8, 72.2, and, 7.0 % of the total COD removal, and 18.7, 81.2, and 0.16 % of the total energy production, respectively. The continuous stirred-tank reactor BioH 2 at HRT of 1 day, up-flow anaerobic sludge blanket BioCH 4 at HRT of 2 days, and MFC reactor at HRT of 3 days were decided in 1:2:3 ratios of working volume under hydraulic retention time consideration. This integration system can be applied to various configurations depending on target wastewater inputs, and it is expected to enhance energy recovery and reduce environmental impact of the final effluent.

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.

High organic loading influences the physical characteristics of aerobic sludge granules.

PubMed

Moy, B Y-P; Tay, J-H; Toh, S-K; Liu, Y; Tay, S T-L

2002-01-01

The effect of high organic loading rate (OLR) on the physical characteristics of aerobic granules was studied. Two column-type sequential aerobic sludge blanket reactors were fed with either glucose or acetate as the main carbon source, and the OLR was gradually raised from 6 to 9, 12 and 15 kg chemical oxygen demand (COD) m(-3) d(-1). Glucose-fed granules could sustain the maximum OLR tested. At a low OLR, these granules exhibited a loose fluffy morphology dominated by filamentous bacteria. At higher OLRs, these granules became irregularly shaped, with folds, crevices and depressions. In contrast, acetate-fed granules had a compact spherical morphology at OLRs of 6 and 9 kg COD m(-3) d(-1), with better settling and strength characteristics than glucose-fed granules at similar OLRs. However, acetate-fed granules could not sustain high OLRs and disintegrated when the OLR reached 9 kg COD m(-3) d(-1). The compact regular microstructure of the acetate-fed granules appeared to limit mass transfer of nutrients at an OLR of 9 kg COD m(-3) d(-1). The looser filamentous microstructure of the glucose-fed granules and the subsequent irregular morphology delayed the onset of diffusion limitation and allowed significantly higher OLRs to be attained. SIGNIFICNACE AND IMPACT OF THE STUDY: High organic loading rates are possible with aerobic granules. This research would be helpful in the development of aerobic granule-based systems for high-strength wastewaters.

Microbial Communities and Their Performances in Anaerobic Hybrid Sludge Bed-Fixed Film Reactor for Treatment of Palm Oil Mill Effluent under Various Organic Pollutant Concentrations

PubMed Central

Meesap, Kanlayanee; Boonapatcharoen, Nimaradee; Techkarnjanaruk, Somkiet; Chaiprasert, Pawinee

2012-01-01

The anaerobic hybrid reactor consisting of sludge and packed zones was operated with organic pollutant loading rates from 6.2 to 8.2 g COD/L day, composed mainly of suspended solids (SS) and oil and grease (O&G) concentrations between 5.2 to 10.2 and 0.9 to 1.9 g/L, respectively. The overall process performance in terms of chemical oxygen demands (COD), SS, and O&G removals was 73, 63, and 56%, respectively. When the organic pollutant concentrations were increased, the resultant methane potentials were higher, and the methane yield increased to 0.30 L CH4/g CODremoved. It was observed these effects on the microbial population and activity in the sludge and packed zones. The eubacterial population and activity in the sludge zone increased to 6.4 × 109 copies rDNA/g VSS and 1.65 g COD/g VSS day, respectively, whereas those in the packed zone were lower. The predominant hydrolytic and fermentative bacteria were Pseudomonas, Clostridium, and Bacteroidetes. In addition, the archaeal population and activity in the packed zone were increased from to 9.1 × 107 copies rDNA/g VSS and 0.34 g COD-CH4/g VSS day, respectively, whereas those in the sludge zone were not much changed. The most represented species of methanogens were the acetoclastic Methanosaeta, the hydrogenotrophic Methanobacterium sp., and the hydrogenotrophic Methanomicrobiaceae. PMID:22927723

Spectroscopic characterization of dissolved organic matter in coking wastewater during bio-treatment: full-scale plant study.

PubMed

Xu, Ronghua; Ou, Huase; Yu, Xubiao; He, Runsheng; Lin, Chong; Wei, Chaohai

2015-01-01

This paper taking a full-scale coking wastewater (CWW) treatment plant as a case study aimed to characterize removal behaviors of dissolved organic matter (DOM) by UV spectra and fluorescence excitation-emission matrix-parallel factor analysis (PARAFAC), and investigate the correlations between spectroscopic indices and water quality parameters. Efficient removal rates of chemical oxygen demand (COD), dissolved organic carbon (DOC) and total nitrogen (TN) after the bio-treatment were 91.3%, 87.3% and 69.1%, respectively. UV270 was proven to be a stable UV absorption peak of CWW that could reflect the mixture of phenols, heterocyclics, polynuclear aromatic hydrocarbons and their derivatives. Molecular weight and aromaticity were increased, and also the content of polar functional groups was greatly reduced after bio-treatment. Three fluorescent components were identified by PARAFAC: C1 (tyrosine-like), C2 (tryptophan-like) and C3 (humic-like). The removal rate of protein-like was higher than that of humic-like and C1 was identified as biodegradable substance. Correlation analysis showed UV270 had an excellent correlation with COD (r=0.921, n=60, P<0.01) and DOC (r=0.959, n=60, P<0.01) and significant correlation (r=0.875, n=60, P<0.01) was also found between C2 and TN. Therefore, spectroscopic characterization could provide novel insights into removal behaviors of DOM and potential to monitor water quality real-time during CWW bio-treatment.

UASB-septic tank as an alternative for decentralized wastewater treatment in Mexico.

PubMed

Santiago-Díaz, Ángel L; García-Albortante, Julisa; Salazar-Peláez, Mónica L

2018-02-05

The aim of this work was to evaluate the performance of a UASB-septic tank as a decentralized treatment of high-strength municipal wastewater under two different HRTs (48 and 72 h). Thus, a lab-scale (44.85 L) UASB-septic tank constituted by three compartments was operated under HRT 72 and 48 h. Removal efficiencies of total chemical oxygen demand (COD), biological oxygen demand (BOD 5 ) and suspended solids (SS) ranged from 60% to 80% for the first two parameters and from 70% to 90% for the last one. According to the statistical analysis, it was established that decreasing HRT from 72 to 48 h did not affect the performance of the UASB-septic tank; therefore, the latter HRT is recommended to be used for operation. In the first compartment, most of the organic matter removal was carried out, while the other two compartments served as polishing. Over the course of six months, the VS concentration and VS/TS ratio in sludge blanket decreased, indicating digestion and stabilization of the retained solids. Also, an increase of 4% in sludge volume was observed; thus, time for desludging would be approximately five years. Comparison of the UASB-septic tank and the UASB reactor showed that both systems had similar performance regarding effluent concentrations of organic matter and solids. Thus, under low volumetric organic load conditions (less than 20 mg COD/L h), the former is an attractive option for municipal wastewater treatment.

Anaerobic reactor/high rate pond combined technology for sewage treatment in the Mediterranean area.

PubMed

El Hafiane, F; El Hamouri, B

2005-01-01

Two high-rate, anaerobic/aerobic units were used to treat the sewage of the Institut Agronomique st Vétérinaire Hassan II (Morocco) campus in a 1,100 m2-plant designed for 1,500 e.p. and receiving 63 m3 per day. The anaerobic pre-treatment consisted of a two-step up-flow anaerobic reactor (TSUAR) comprising two reactors and one external settler all in series. The aerobic line, or post-treatment, consisted of a high-rate algal pond (HRAP) and one maturation pond in series. The system totalized a hydraulic retention time (HRT) of 9 days. A gravel filter (GF) was constructed behind the TSUAR to trap low-density particles. The TSUAR removed 80% of COD and 90% of SS within 48 h. Solids retention time in the reactors averaged 32 d with a specific sludge production of 0.28 g SS g(-1) COD removed. Almost 93% of the sludge evacuated from the settler was stabilized. Specific biogas production from both reactors was 0.25m3 kg(-1) COD removed. Used in this configuration, the HRAP lost its BOD removal activity and increased its nutrients and pathogens removal capabilities (tertiary treatment). Results showed that 85% of total nitrogen and 48% of total phosphorus were removed by the HRAP. Land area requirement of this combination was less than 1 m2 per capita and filtered final effluent was of excellent quality (COD, 82 mg/l; TKN, 8.3 mg/l; total P, 2.7 mg/l, faecal coliforms, 2.4 10(3)/100 ml and zero helminths eggs).

The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing.

PubMed

Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

2015-01-01

In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process.

The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing

PubMed Central

Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

2015-01-01

In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process. PMID:26461260

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.

Winery wastewater treatment by a combined process: long term aerated storage and Fenton's reagent.

PubMed

Lucas, Marco S; Mouta, Maria; Pirra, António; Peres, José A

2009-01-01

The degradation of the organic pollutants present in winery wastewater was carried out by the combination of two successive steps: an aerobic biological process followed by a chemical oxidation process using Fenton's reagent. The main goal of this study was to evaluate the temporal characteristics of solids and chemical oxygen demand (COD) present in winery wastewater in a long term aerated storage bioreactor. The performance of different air dosage daily supplied to the biologic reactor, in laboratory and pilot scale, were examined. The long term hydraulic retention time, 11 weeks, contributed remarkably to the reduction of COD (about 90%) and the combination with the Fenton's reagent led to a high overall COD reduction that reached 99.5% when the mass ratio (R = H(2)O(2)/COD) used was equal to 2.5, maintaining constant the molar ratio H(2)O(2)/Fe(2+)=15.

Treatment of low strength industrial cluster wastewater by anaerobic hybrid reactor.

PubMed

Kumar, Amit; Yadav, Asheesh Kumar; Sreekrishnan, T R; Satya, Santosh; Kaushik, C P

2008-05-01

The study was aimed at treating the complex, combined wastewater generated in Mangolpuri industrial cluster. It was considered as a low strength wastewater with respect to its organic content. Anaerobic treatment of this wastewater was studied using an anaerobic hybrid reactor (AHR) which combined the best features of both the upflow anaerobic sludge blanket (UASB) reactor and anaerobic fluidized bed rector (AFBR). The performance of the reactor under different organic and hydraulic loading rates were studied. The COD removal reached 94% at an organic loading rate (OLR) of 2.08 kg COD m(-3)d(-1) at an hydraulic retention time (HRT) of 6.0 h. The granules developed were characterized in terms of their diameter and terminal settling velocity.

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.

Combined biodegradation and ozonation for removal of tannins and dyes for the reduction of pollution loads.

PubMed

Kanagaraj, James; Mandal, Asit Baran

2012-01-01

Tannins and dyes pose major threat to the environment by generating huge pollution problem. Biodegradation of wattle extract, chrome tannin and dye compounds using suitable fungal culture namely Aspergillus niger, Penicillium sp. were carried out. In addition to these, ozone treatment was carried out to get higher degradation rate. The results were monitored by carrying out chemical oxygen demand (COD), total organic carbon (TOC), and UV-Vis analysis. The results showed that wattle extract (vegetable tannin) gave better biodegradation rate than dye and chromium compounds. Biodegradation plus ozone showed degradation rates of 92-95%, 94-95%, and 85-87% for the wattle extract, dyes, chromium compounds, respectively. UV-Vis showed that there were no peaks observed for biodegraded samples indicating better degradation rates as compared to the control samples. FT-IR spectra analysis suggested that the formation of flavanoid derivatives, chromic oxide and NH(2) compounds during degradation of wattle extract, chromium and dye compounds, respectively, at the peaks of 1,601-1,629 cm(-1), 1,647 cm(-1), and 1,610-1,680 cm(-1). The present investigation shows that combination of biodegradation with ozone is the effective method for the removal of dyes and tannins. The biodegradation of the said compounds in combination with ozonation showed better rate of degradation than by chemical methods. The combination of biodegradation with ozone helps to reduce pollution problems in terms of COD, TOC, total dissolved solids and total suspended solids.

Olive mill wastewater stabilization in open-air ponds: impact on clay-sandy soil.

PubMed

Jarboui, Raja; Sellami, Fatma; Kharroubi, Adel; Gharsallah, Néji; Ammar, Emna

2008-11-01

The aim of this work was to study the natural biodegradation of the stored olive mill wastewater (OMW) in ponds and the infiltration as well as the impact on soil of the effluent in the evaporation pond used for the storage over the past eight years. For this, two approaches were considered. First, a laboratory-scale column was used for the infiltration of OMW through soil (clay and sand) to predict the effect of the clayey soil in reducing OMW pollution. Second, the ponds including the effluent annually stored and having this clayey structure were investigated. At the laboratory-scale, a modification of OMW contents was noticed, with the elimination of 95% of total suspended solids (TSS), 60% of chemical oxygen demand (COD), 40% of total organic carbon (TOC), 50% of total P, 50% of phenols and 40% of minerals (K+, Mg++ and Na+). The experimented soil was able to restrain the considerable effects of OMW pollution. In the ponds, the granulometric characteristics, the physico-chemical and the biological parameters of the soil profile from the contaminated pond were compared to those of a control soil, located near the contaminated pond. Property modifications of the contaminated soil were noted, especially pH, electrical conductivity, COD and microflora. These changes can be explained by the infiltration of OMW constituents, which were noticed in the soil layers, especially phenolic compounds that have a negative effect on the ground water.

Advanced Treatment of Pesticide-Containing Wastewater Using Fenton Reagent Enhanced by Microwave Electrodeless Ultraviolet

PubMed Central

Cheng, Gong; Lin, Jing; Lu, Jian; Zhao, Xi; Cai, Zhengqing; Fu, Jie

2015-01-01

The photo-Fenton reaction is a promising method to treat organic contaminants in water. In this paper, a Fenton reagent enhanced by microwave electrodeless ultraviolet (MWEUV/Fenton) method was proposed for advanced treatment of nonbiodegradable organic substance in pesticide-containing biotreated wastewater. MWEUV lamp was found to be more effective for chemical oxygen demand (COD) removal than commercial mercury lamps in the Fenton process. The pseudo-first order kinetic model can well describe COD removal from pesticide-containing wastewater by MWEUV/Fenton, and the apparent rate constant (k) was 0.0125 min−1. The optimal conditions for MWEUV/Fenton process were determined as initial pH of 5, Fe2+ dosage of 0.8 mmol/L, and H2O2 dosage of 100 mmol/L. Under the optimal conditions, the reaction exhibited high mineralization degrees of organics, where COD and dissolved organic carbon (DOC) concentration decreased from 183.2 mg/L to 36.9 mg/L and 43.5 mg/L to 27.8 mg/L, respectively. Three main pesticides in the wastewater, as Dimethoate, Triazophos, and Malathion, were completely removed by the MWEUV/Fenton process within 120 min. The high degree of pesticides decomposition and mineralization was proved by the detected inorganic anions. PMID:26347877

A combined electrocoagulation-electrooxidation treatment for industrial wastewater.

PubMed

Linares-Hernández, Ivonne; Barrera-Díaz, Carlos; Bilyeu, Bryan; Juárez-GarcíaRojas, Pablo; Campos-Medina, Eduardo

2010-03-15

This study addresses the elimination of persistent organic compounds in industrial wastewater using a synergistic combination of electrocoagulation and electrooxidation. Electrocoagulation is a relatively quick process (30 min), which is very effective in removing colloidal and suspended particles, as seen in changes in coliforms, turbidity, and color and in the general absorbance by UV-vis spectroscopy. However, it is relatively ineffective in eliminating stable persistent organic compounds--in this work, only half of the COD was eliminated from wastewater and an oxidation peak in the cyclic voltammetry scan remained. Electrooxidation is very effective in breaking down organic compounds through oxidation as reflected in the elimination of COD, BOD(5), and oxidative peak in cyclic voltammetry, but requires so much time (21 h) that it has very limited practicality, especially when colloidal and suspended particles are present. Electrooxidative mineralization of electrocoagulated wastewater, in which most of the colloids and charged species have been removed, takes less than 2h. In the coupled technique, electrocoagulation quickly coagulates and removes the colloidal and suspended particles, as well as many charged species, then electrooxidation oxidizes the remaining organics. The coupled process eliminates COD, BOD(5), color, turbidity, and coliforms in a practical amount of time (2h). (c) 2009 Elsevier B.V. All rights reserved.

The Effects of Plyometric Training on Change-of-Direction Ability: A Meta-Analysis.

PubMed

Asadi, Abbas; Arazi, Hamid; Young, Warren B; Sáez de Villarreal, Eduardo

2016-07-01

To show a clear picture about the possible variables of enhancements of change-of-direction (COD) ability using longitudinal plyometric-training (PT) studies and determine specific factors that influence the training effects. A computerized search was performed, and 24 articles with a total of 46 effect sizes (ESs) in an experimental group and 25 ESs in a control group were reviewed to analyze the role of various factors on the impact of PT on COD performance. The results showed that participants with good fitness levels obtained greater improvements in COD performance (P < .05), and basketball players gained more benefits of PT than other athletes. Also, men obtained COD results similar to those of women after PT. In relation to the variables of PT design, it appears that 7 wk (with 2 sessions/wk) using moderate intensity and 100 jumps per training session with a 72-h rest interval tends to improve COD ability. Performing PT with a combination of different types of plyometric exercises such as drop jumps + vertical jumps + standing long jumps is better than 1 form of exercise. It is apparent that PT can be effective at improving COD ability. The loading parameters are essential for exercise professionals, coaches, and strength and conditioning professionals with regard to the most appropriate dose-response trends to optimize plyometric-induced COD-ability gains.

Research on leachate recirculation from different types of landfills

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

Wang Qi; Matsufuji, Yasushi; Dong Lu

2006-07-01

Landfills can produce a great amount of leachate containing highly concentrated organic matter. This is especially true for the initial leachate from landfilled municipal solid wastes (MSW) that generally has concentrations of COD{sub Cr} and BOD{sub 5} up to 80,000 and 50,000 mg/L, respectively. The leachate could be disposed by means of recirculating technique, which decomposes the organics through the action of proliferating microorganisms and thereby purifies the leachate, and simultaneously accelerates organic decomposition through water saturation control. Data from experimental results indicated that leachate recirculating could reduce the organic concentration considerably, with a maximum reduction rate of COD{sub Cr}more » over 95%; and, using a semi-aerobic process, NH{sub 3}-N concentration of treated leachate could be under 10 mg/L. In addition, the organic concentration in MSW decreased greatly.« less

Performance evaluation of a granular activated carbon-sequencing batch biofilm reactor pilot plant system used in treating real wastewater from recycled paper industry.

PubMed

Muhamad, Mohd Hafizuddin; Sheikh Abdullah, Siti Rozaimah; Mohamad, Abu Bakar; Rahman, Rakmi Abdul; Kadhum, Abdul Amir Hasan

2012-01-01

A pilot scale granular activated carbon-sequencing batch biofilm reactor with a capacity of 2.2 m3 was operated for over three months to evaluate its performance treating real recycled paper industry wastewater under different operational conditions. In this study, dissolved air floatation (DAF) and clarifier effluents were used as influent sources of the pilot plant. During the course of the study, the reactor was able to biodegrade the contaminants in the incoming recycled paper mill wastewater in terms of chemical oxygen demand (COD), adsorbable organic halides (AOX; specifically 2,4-dichlorophenol (2,4-DCP)) and ammoniacal nitrogen (NH3-N) removal efficiencies at varying hydraulic retention times (HRTs) of 1-3 days, aeration rates (ARs) of 2.1-3.4 m3/min and influent feed concentration of 40-950 mg COD/l. Percentages of COD, 2,4-DCP and NH3-N removals increased with increasing HRT, resulting in more than 90% COD, 2,4-DCP and NH3-N removals at HRT values above two days. Degradation of COD, 2,4-DCP and NH3-N were seriously affected by variation of ARs, which resulted in significant decrease of COD, 2,4-DCP and NH3-N removals by decreasing ARs from 3.4 m3/min to 2.1 m3/min, varying in the ranges of 24-80%, 6-96% and 5-42%, respectively. In comparison to the clarifier effluent, the treatment performance of DAF effluent, containing high COD concentration, resulted in a higher COD removal of 82%. The use of diluted DAF effluent did not improve significantly the COD removal. Higher NH3-N removal efficiency of almost 100% was observed during operation after maintenance shutdown compared to normal operation, even at the same HRT of one day due to the higher dissolved oxygen concentrations (1-7 mg/l), while no significant difference in COD removal efficiency was observed.

Reuse of drinking water treatment sludge for olive oil mill wastewater treatment.

PubMed

Fragoso, R A; Duarte, E A

2012-01-01

Olive mill wastewater (OMW) results from the production of olive oil, which is an important traditional agro-industry in Mediterranean countries. In continuous three-phase centrifugation 1.0-1.2 m(3) of OMW are produced per ton of processed olives. Discharge of OMW is of serious environmental concern due to its high content of organic matter with phytotoxic properties, namely phenolic compounds. Meanwhile, drinking water treatment sludge (DWTS) is produced in high amounts and has long been considered as a waste for landfill. The aim of this work was the assessment of reusing DWTS for OMW treatment. High performance liquid chromatography (HPLC) analysis was carried out to determine the phenolic compounds present and to evaluate if they are recalcitrant. Treatability assays were performed using a dosage of DWTS from 50 to 300 g L(-1). Treatment efficiency was evaluated based on the removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total solids (TS), total suspended solids (TSS), total volatile solids (TVS), oil and grease (OG), phenols (total phosphorous (TP) and HPLC fraction). Results from OMW HPLC characterization identified a total of 13 compounds; the major ones were hydroxytyrosol, tyrosol, caffeic acid, p-cumaric acid and oleuropein. Treatability assays led to a maximum reduction of about 90% of some of the phenolic compounds determined by HPLC. Addition of 200-300 g L(-1) of DWTS reduced 40-50% of COD, 45-50% of TP, a maximum of nearly 70% TSS and 45% for TS and TVS. The OG fraction showed a reduction of about 90%, achieved adding 300 g L(-1) od DWTS. This study points out the possibility of establishing an integrated management of OMW and DWTS, contributing to a decrease in the environmental impact of two industrial activities, olive oil production and drinking water treatment.

Characterization and first flush analysis in road and roof runoff in Shenyang, China.

PubMed

Li, Chunlin; Liu, Miao; Hu, Yuanman; Gong, Jiping; Sun, Fengyun; Xu, Yanyan

2014-01-01

As urbanization increases, urban runoff is an increasingly important component of total urban non-point source pollution. In this study, the properties of urban runoff were examined in Shenyang, in northeastern China. Runoff samples from a tiled roof, a concrete roof and a main road were analyzed for key pollutants (total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), Pb, Cd, Cr, Cu, Ni, and Zn). The event mean concentration, site mean concentration, M(V) curves (dimensionless cumulative curve of pollutant load with runoff volume), and mass first flush ratio (MFF30) were used to analyze the characteristics of pollutant discharge and first flush (FF) effect. For all events, the pollutant concentration peaks occurred in the first half-hour after the runoff appeared and preceded the flow peaks. TN is the main pollutant in roof runoff. TSS, TN, TP, Pb, and Cr are the main pollutants in road runoff in Shenyang. There was a significant correlation between TSS and other pollutants except TN in runoff, which illustrated that TSS was an important carrier of organic matter and heavy metals. TN had strong positive correlations with total rainfall (Pearson's r = 0.927), average rainfall (Pearson's r = 0.995), and maximum rainfall intensity (Pearson's r = 0.991). TP had a strong correlation with rainfall intensity (Pearson's r = 0.940). A significant positive correlation between COD and rainfall duration (Pearson's r = 0.902, significance level = 0.05) was found. The order of FF intensity in different surfaces was concrete roof > tile roof > road. Rainfall duration and the length of the antecedent dry period were positively correlated with the FF. TN tended to exhibit strong flush for some events. Heavy metals showed a substantially stronger FF than other pollutant.

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.

The impact of CodY on virulence determinant production in community-associated methicillin-resistant Staphylococcus aureus.

PubMed

Rivera, Frances E; Miller, Halie K; Kolar, Stacey L; Stevens, Stanley M; Shaw, Lindsey N

2012-01-01

Staphylococcus aureus is a leading human pathogen of both hospital and community-associated diseases worldwide. This organism causes a wealth of infections within the human host as a result of the vast arsenal of toxins encoded within its genome. Previous transcriptomic studies have shown that toxin production in S. aureus can be strongly impacted by the negative regulator CodY. CodY acts by directly, and indirectly (via Agr), repressing toxin production during times of plentiful nutrition. In this study, we use iTRAQ-based proteomics for the first time to study virulence determinant production in S. aureus, so as to correlate transcriptional observations with actual changes in protein synthesis. Using a codY mutant in the epidemic CA-MRSA clone USA300 we demonstrate that deletion of this transcription factor results in a major upregulation of toxin synthesis in both post-exponential and stationary growth. Specifically, we observe hyper-production of secreted proteases, leukocidins and hemolysins in both growth phases in the USA300 codY mutant. Our findings demonstrate the power of mass spectrometry-based quantitative proteomics for studying toxin production in S. aureus, and the importance of CodY to this central process in disease causation and infection. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anaerobic accumulation of short-chain fatty acids from algae enhanced by damaging cell structure and promoting hydrolase activity.

PubMed

Feng, Leiyu; Chen, Yunzhi; Chen, Xutao; Duan, Xu; Xie, Jing; Chen, Yinguang

2018-02-01

Short-chain fatty acid (SCFAs) produced from harvested algae by anaerobic fermentation with uncontrolled pH was limited due to the solid cell structure of algae. This study, therefore, was undertaken to enhance the generation of SCFAs from algae by controlling the fermentation pH. pH influenced not only the total SCFAs production, but the percentage of individual SCFA. The maximal yield of SCFAs occurred at pH 10.0 and fermentation time of 6 d (3161 mg COD/L), which mainly contained acetic and iso-valeric acids and was nearly eight times that at uncontrolled pH (392 mg COD/L). Mechanism exploration revealed at alkaline pH, especially at pH 10.0, not only the cell structure of algae was damaged effectively, but also activities and relative quantification of hydrolases as well as the abundance of microorganisms responsible for organics hydrolysis and SCFAs production were improved. Also, the released microcystins from algae were removed efficiently during alkaline anaerobic fermentation. Copyright © 2017 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.

Performance of UASB septic tank for treatment of concentrated black water within DESAR concept.

PubMed

Kujawa-Roeleveld, K; Fernandes, T; Wiryawan, Y; Tawfik, A; Visser, M; Zeeman, G

2005-01-01

Separation of wastewater streams produced in households according to their origin, degree of pollution and affinity to a specific treatment constitutes a starting point in the DESAR concept (decentralised sanitation and reuse). Concentrated black water and kitchen waste carry the highest load of organic matter and nutrients from all waste(water)streams generated from different human activities. Anaerobic digestion of concentrated black water is a core technology in the DESAR concept. The applicability of the UASB septic tank for treatment of concentrated black water was investigated under two different temperatures, 15 and 25 degrees C. The removal of total COD was dependent on the operational temperature and attained 61 and 74% respectively. A high removal of the suspended COD of 88 and 94% respectively was measured. Effluent nutrients were mainly in the soluble form. Precipitation of phosphate was observed. Effective sludge/water separation, long HRT and higher operational temperature contributed to a reduction of E. coli. Based on standards there is little risk of contamination with heavy metals when treated effluent is to be applied in agriculture as fertiliser.

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.

Treating refinery wastewaters in microbial fuel cells using separator electrode assembly or spaced electrode configurations.

PubMed

Zhang, Fang; Ahn, Yongtae; Logan, Bruce E

2014-01-01

The effectiveness of refinery wastewater (RW) treatment using air-cathode, microbial fuel cells (MFCs) was examined relative to previous tests based on completely anaerobic microbial electrolysis cells (MECs). MFCs were configured with separator electrode assembly (SEA) or spaced electrode (SPA) configurations to measure power production and relative impacts of oxygen crossover on organics removal. The SEA configuration produced a higher maximum power density (280±6 mW/m(2); 16.3±0.4 W/m(3)) than the SPA arrangement (255±2 mW/m(2)) due to lower internal resistance. Power production in both configurations was lower than that obtained with the domestic wastewater (positive control) due to less favorable (more positive) anode potentials, indicating poorer biodegradability of the RW. MFCs with RW achieved up to 84% total COD removal, 73% soluble COD removal and 92% HBOD removal. These removals were higher than those previously obtained in mini-MEC tests, as oxygen crossover from the cathode enhanced degradation in MFCs compared to MECs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phosphorus recovery from fosfomycin pharmaceutical wastewater by wet air oxidation and phosphate crystallization.

PubMed

Qiu, Guanglei; Song, Yonghui; Zeng, Ping; Xiao, Shuhu; Duan, Liang

2011-06-01

Fosfomycin pharmaceutical wastewater contains highly concentrated and refractory antibiotic organic phosphorus (OP) compounds. Wet air oxidation (WAO)-phosphate crystallization process was developed and applied to fosfomycin pharmaceutical wastewater pretreatment and phosphorus recovery. Firstly, WAO was used to transform concentrated and refractory OP substances into inorganic phosphate (IP). At 200°C, 1.0MPa and pH 11.2, 99% total OP (TOP) was transformed into IP and 58% COD was reduced. Subsequently, the WAO effluent was subjected to phosphate crystallization process for phosphorus recovery. At Ca/P molar ratio 2.0:1.0 or Mg/N/P molar ratio 1.1:1.0:1.0, 99.9% phosphate removal and recovery were obtained and the recovered products were proven to be hydroxyapatite and struvite, respectively. After WAO-phosphate crystallization, the BOD/COD ratio of the wastewater increased from 0 to more than 0.5, which was suitable for biological treatment. The WAO-phosphate crystallization process was proven to be an effective method for phosphorus recovery and for fosfomycin pharmaceutical wastewater pretreatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

Clofibric acid and gemfibrozil removal in membrane bioreactors.

PubMed

Gutierrez-Macias, Tania; Nacheva, Petia Mijaylova

2015-01-01

The removal of two blood lipid regulators, clofibric acid (CLA) and gemfibrozil (GFZ), was evaluated using two identical aerobic membrane bioreactors with 6.5 L effective volume each. Polysulfone ultrafiltration hollow fiber membranes were submerged in the reactors. Different operating conditions were tested varying the organic load (F/M), hydraulic residence time (HRT), biomass concentration measured as total suspended solids in the mixed liquor (MLTSS) and the sludge retention time (SRT). Complete GFZ removal was obtained with F/M of 0.21-0.48 kg COD kgTSS⁻¹ d⁻¹, HRT of 4-10 hours, SRT of 10-32 d and MLTSS of 6-10 g L⁻¹. The GFZ removal can be attributed to biodegradation and there was no accumulation of the compound in the biomass. The CLA removals improved with the SRT and HRT increase and F/M decrease. Average removals of 78-79% were obtained with SRT 16-32 d, F/M of 0.21-0.34 kgCOD kgTSS⁻¹ d⁻¹, HRT of 7-10 hours and MLTSS of 6-10 g L⁻¹. Biodegradation was found to be the main removal pathway.

Applicability of Fluorescence and Absorbance Spectroscopy to Estimate Organic Pollution in Rivers

PubMed Central

Knapik, Heloise Garcia; Fernandes, Cristovão Vicente Scapulatempo; de Azevedo, Júlio Cesar Rodrigues; do Amaral Porto, Monica Ferreira

2014-01-01

Abstract This article explores the applicability of fluorescence and absorbance spectroscopy for estimating organic pollution in polluted rivers. The relationship between absorbance, fluorescence intensity, dissolved organic carbon, biochemical oxygen demand (BOD), chemical oxygen demand (COD), and other water quality parameters were used to characterize and identify the origin and the spatial variability of the organic pollution in a highly polluted watershed. Analyses were performed for the Iguassu River, located in southern Brazil, with area about 2,700 km2 and ∼3 million inhabitants. Samples were collect at six monitoring sites covering 107 km of the main river. BOD, COD, nitrogen, and phosphorus concentration indicates a high input of sewage to the river. Specific absorbance at 254 and 285 nm (SUVA254 and A285/COD) did not show significant variation between sites monitored, indicating the presence of both dissolved compounds found in domestic effluents and humic and fulvic compounds derived from allochthonous organic matter. Correlations between BOD and tryptophan-like fluorescence peak (peak T2, r=0.7560, and peak T1, r=0.6949) and tyrosine-like fluorescence peak (peak B, r=0.7321) indicated the presence of labile organic matter and thus confirmed the presence of sewage in the river. Results showed that fluorescence and absorbance spectroscopy provide useful information on pollution in rivers from critical watersheds and together are a robust method that is simpler and more rapid than traditional methods employed by regulatory agencies. PMID:25469076

77 FR 62464 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Using Pot Gear in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-15

... Vessels Using Pot Gear in the Central Regulatory Area of the Gulf of Alaska AGENCY: National Marine... gear in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary to prevent exceeding the 2012 Pacific cod total allowable catch apportioned to vessels using pot gear in the Central...

78 FR 13812 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Catch Vessels Using Trawl...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-01

.... 1801 et seq. Dated: February 26, 2013. Kara Meckley, Acting Deputy Director, Office of Sustainable... hours. This action is necessary to fully use the A season allowance of the 2013 Pacific cod total...: Effective 1200 hours, Alaska local time (A.l.t.), March 1, 2013, through 1200 hours, A.l.t., March 3, 2013...

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.

Packed- and fluidized-bed biofilm reactor performance for anaerobic wastewater treatment.

PubMed

Denac, M; Dunn, I J

1988-07-05

Anaerobic degradation performance of a laboratory-scale packed-bed reactor (PBR) was compared with two fluidized-bed biofilm reactors (FBRs) on molasses and whey feeds. The reactors were operated under constant pH (7) and temperature (35 degrees C) conditions and were well mixed with high recirculation rates. The measured variables were chemical oxygen demand (COD), individual organic acids, gas composition, and gas rates. As carrier, sand of 0.3-0.5 mm diameter was used in the FBR, and porous clay spheres of 6 mm diameter were used in the PBR. Startup of the PBR was achieved with 1-5 day residence times. Start-up of the FBR was only successful if liquid residence times were held low at 2-3 h. COD degradations of 86% with molasses (90% was biodegradable) were reached in both the FBR and PBR at 6 h residence time and loadings of 10 g COD/L day. At higher loadings the FBR gave the best performance; even at 40-45 g COD/L day, with 6 h residence times, 70% COD was degraded. The PBR could not be operated above 20 g COD/L day without clogging. A comparison of the reaction rates show that the PBR and FBR per formed similarly at low concentrations in the reactors up to 1 g COD/L, while above 3 g COD/L the rates were 17.4 g COD/L day for the PBR and 38.4 g COD/L day for the FBR. This difference is probably due to diffusion limitations and a less active biomass content of the PBR compared with the fluidized bed.The results of dynamic step change experiments, in which residence times and feed concentrations were changed hanged at constant loading, demonstrated the rapid response of the reactors. Thus, the response times for an increase in gas rate or an increase in organic acids due to an increase in feed concentration were less than 1 day and could be explained by substrate limitation. Other slower responses were observed in which the reactor culture adapted over periods of 5-10 days; these were apparently growth related. An increase in loading of over 100% always resulted in large increases inorganic acids, especially acetic and propionic, as well as large increases in the CO(2) gas content. In general, the CO(2) content of the gas was very low, due to the large amount of dissolved CO(2) that exited with the liquid phase at low residence times. The performance of the FBR with whey was comparable to its performance with molasses, and switching of molasses to whey feed resulted in immediate good performance without adaptation.

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.

Anaerobic digestion of glycerol and co-digestion of glycerol and pig manure.

PubMed

Nuchdang, Sasikarn; Phalakornkule, Chantaraporn

2012-06-30

The potential of glycerol obtained from transesterification of waste cooking oil as a main carbon source for biogas production was investigated. The glycerol was highly contaminated with oils and fats and was pretreated with sulfuric acid. Using a carbon source of glucose as a control, we compared biogas production from the acid-treated glycerol in a synthetic medium and the acid-treated glycerol mixed with pig manure. The anaerobic digestion of acid-treated glycerol with supplement in a synthetic medium was found to be satisfactory at organic loading rates (OLR) between 1.3, 1.6 and 2.6 g chemical oxygen demand (COD) L(-1) d(-1). The maximum methane yield of 0.32 L at Standard temperature and pressure (STP) g(-1) COD removal was achieved at an OLR of 1.6 g COD L(-1) d(-1) and the methane content was 54% on an average. At a higher organic loading rate of 5.4 g COD L(-1) d(-1), the propionic acid to acetic acid ratio was higher than the critical threshold limit for metabolic imbalance. Anaerobic digestion of acid-treated glycerol with pig manure was also investigated at the COD ratio of 80:20 (glycerol:pig manure). The anaerobic digestion of acid-treated glycerol with pig manure was found to be satisfactory at organic loading rates between 1.3, 1.7, 2.9 and 5.0 g COD L(-1) d(-1) in terms of COD reduction (>80%) and methane content of (62% on an average). However, the biogas production rate was found to significantly decrease at the highest load. The maximum methane yield of 0.24 L STP g(-1) COD removal was achieved at an OLR of 1.3 g COD L(-1) d(-1). Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of organic nitrogen concentration on the efficiency of trickling filters

NASA Astrophysics Data System (ADS)

Kopeć, Łukasz; Drewnowski, Jakub; Fernandez-Morales, F. J.

2018-02-01

The study was conducted in Poland at six selected wastewater treatment plants (WWTP) based on the trickling filters Bioclere® technology. The aim of the study was to find the relationship between the influent organic nitrogen concentration and the purification efficiency expressed as effluent COD concentration. In the tests performed, the COD to BOD5 relationship was close to 2 and the ratio of BOD5 to TN was lower than 4. The research indicated that this specific chemical composition of raw wastewater causes appearance of filamentous bacteria on the surface of trickling filter filling and strongly affect the effluent quality.

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.

The monitoring of organic waste pollution in the sibelis river

NASA Astrophysics Data System (ADS)

Huda, Thorikul; Jannah, Wirdatul

2017-03-01

Has conducted monitoring of organic waste pollution in the River Sibelis of Tegal City of Central Java. Organic wastes that pollute River Sibelis can degrade the quality of well water along the river. Monitoring carried out in the upstream and downstream by chemical oxygen demand (COD) and biochemical oxygen demand (BOD) parameters. COD test methods by titration and the results are used to determine the test sample comparison with the volume of diluent required for analysts BOD. COD test results on the upstream and downstream Sibelis River respectively 58.13 mg/L and 73.97 mg / L so that the ratio of the test sample with diluent volume for BOD analysis is 20: 280 (Sawyer, 1978). BOD test principle is based on the reduction of dissolved oxygen zero day (DO0) and five days (DO5). The result of observation BOD samples at upstream and downstream Sibelis Rivers are 10.7212 mg / L and 5.3792 mg / L respectively. Quality control of BOD testing conducted with measurement accuracy and precision and obtained result are 85.36% and 0.27% respectively. The result of uncertainty measurement for BOD testing at upstream and downstream are ±0.4469 mg/L and ±0.22188 mg/L.

Occurrence of organic wastewater contaminants, pharmaceuticals, and personal care products in selected water supplies, Cape Cod, Massachusetts, June 2004

USGS Publications Warehouse

Zimmerman, Marc J.

2005-01-01

In June 2004, the U.S. Geological Survey, in cooperation with the Barnstable County Department of Health and Environment, sampled water from 14 wastewater sources and drinking-water supplies on Cape Cod, Massachusetts, for the presence of organic wastewater contaminants, pharmaceuticals, and personal care products. The geographic distribution of sampling locations does not represent the distribution of drinking-water supplies on Cape Cod. The environmental presence of the analyte compounds is mostly unregulated; many of the compounds are suspected of having adverse ecological and human health effects. Of the 85 different organic analyte compounds, 43 were detected, with 13 detected in low concentrations (less than 1 microgram per liter) from drinking-water supplies thought to be affected by wastewater because of previously detected high nitrate concentrations. (Phenol and d-limonene, detected in equipment blanks at unacceptably high concentrations, are not included in counts of detections in this report.) Compounds detected in the drinking-water supplies included the solvent, tetrachloroethylene; the analgesic, acetaminophen; the antibiotic, sulfamethoxazole; and the antidepressant, carbamazapine. Nitrate nitrogen, an indicator of wastewater, was detected in water supplies in concentrations ranging from 0.2 to 8.8 milligrams per liter.

Using ozone to reduce recalcitrant compounds and to enhance biodegradability of pulp and paper effluents.

PubMed

Bijan, L; Mohseni, M

2004-01-01

The effect of ozone based oxidation on removing recalcitrant organic matter (ROM) and enhancing the biodegradability of alkaline bleach plant effluent was investigated. A bubble column ozonation tower was used in the study. The experiments were carried out at different temperatures (20 degrees C and 60 degrees C) and pH (9 and 11), with a number of biological and chemical parameters being monitored including BOD5, COD, TC, pH, color, and molecular weight distribution of organics (nominal cut off of 1,000 Da). Biodegradability of the effluent was determined based on BOD5/COD of the wastewater throughout the process. For all the experiments, ozonation enhanced the biodegradability of the effluent by 30-40%, which was associated with noticeable removal of ROM including high molecular weight (HMW) and color-causing organics by about 30% and 60%, respectively. While the biodegradability of HMW fraction increased by about 50%, there was no biodegradability improvement for low molecular weight (LMW) portion, which was originally readily biodegradable (with BOD5/COD of about 0.5). Statistical analysis of variance (ANOVA) revealed neither pH nor temperature played significant role on the ozonation process at 95% confidence level.

Will urban expansion lead to an increase in future water pollution loads?--a preliminary investigation of the Haihe River Basin in northeastern China.

PubMed

Dong, Yang; Liu, Yi; Chen, Jining

2014-01-01

Urban expansion is a major driving force changing regional hydrology and nonpoint source pollution. The Haihe River Basin, the political, economic, and cultural center of northeastern China, has undergone rapid urbanization in recent decades. To investigate the consequences of future urban sprawl on nonpoint source water pollutant emissions in the river basin, the urban sprawl in 2030 was estimated, and the annual runoff and nonpoint source pollution in the Haihe River basin were simulated. The Integrated Model of Non-Point Sources Pollution Processes (IMPULSE) was used to simulate the effects of urban sprawl on nonpoint source pollution emissions. The outcomes indicated that the urban expansion through 2030 increased the nonpoint source total nitrogen (TN), total phosphorous (TP), and chemical oxygen demand (COD) emissions by 8.08, 0.14, and 149.57 kg/km(2), respectively. Compared to 2008, the total nonpoint emissions rose by 15.33, 0.57, and 12.39 %, respectively. Twelve percent of the 25 cities in the basin would increase by more than 50 % in nonpoint source TN and COD emissions in 2030. In particular, the nonpoint source TN emissions in Xinxiang, Jiaozuo, and Puyang would rise by 73.31, 67.25, and 58.61 %, and the nonpoint source COD emissions in these cities would rise by 74.02, 51.99, and 53.27 %, respectively. The point source pollution emissions in 2008 and 2030 were also estimated to explore the effects of urban sprawl on total water pollution loads. Urban sprawl through 2030 would bring significant structural changes of total TN, TP, and COD emissions for each city in the area. The results of this study could provide insights into the effects of urbanization in the study area and the methods could help to recognize the role that future urban sprawl plays in the total water pollution loads in the water quality management process.

Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation.

PubMed

Velasco, Antonio; Ramírez, Martha; Volke-Sepúlveda, Tania; González-Sánchez, Armando; Revah, Sergio

2008-03-01

The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO4(2-) ratio. This work relates the feed COD/SO4(2-) ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470+/-7 mg S/L was obtained at a feed COD/SO4(2-) ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145+/-10 mg S/L) was observed with a feed COD/SO4(2-) ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO4(2-) ratio of 1.5. It was found that the feed COD/SO4(2-) ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead.

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 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.

Pilot-scale experiment on anaerobic bioreactor landfills in China.

PubMed

Jiang, Jianguo; Yang, Guodong; Deng, Zhou; Huang, Yunfeng; Huang, Zhonglin; Feng, Xiangming; Zhou, Shengyong; Zhang, Chaoping

2007-01-01

Developing countries have begun to investigate bioreactor landfills for municipal solid waste management. This paper describes the impacts of leachate recirculation and recirculation loadings on waste stabilization, landfill gas (LFG) generation and leachate characteristics. Four simulated anaerobic columns, R1-R4, were each filled with about 30 tons of waste and recirculated weekly with 1.6, 0.8 and 0.2m(3) leachate and 0.1m(3) tap water. The results indicated that the chemical oxygen demand (COD) half-time of leachate from R1 was about 180 days, which was 8-14 weeks shorter than that of R2-R4. A large amount of LFG was first produced in R1, and its generation rate was positively correlated to the COD or volatile fatty acid concentrations of influent leachates after the 30th week. By the 50th week of recirculation, the waste in R1 was more stabilized, with 931.2 kg COD or 175.6 kg total organic carbon released and with the highest landfill gas production. However, this contributed mainly to washout by leachate, which also resulted in the reduction of LFG generation potential and accumulation of ammonia and/or phosphorus in the early stage. Therefore, the regimes of leachate recirculation should be adjusted to the phases of waste stabilization to enhance efficiency of energy recovery. Integrated with the strategy of in situ leachate management, extra pre-treatment or post-treatment methods to remove the nutrients are recommended.

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.

Performance of a commercial industrial-scale UF-based process for treatment of oily wastewaters.

PubMed

Karhu, M; Kuokkanen, T; Rämö, J; Mikola, M; Tanskanen, J

2013-10-15

An evaluation was made of the performance of a commercial industrial-scale ultrafiltration (UF)-based process for treatment of highly concentrated oily wastewaters. Wastewater samples were gathered from two plants treating industrial wastewaters in 2008, and in 2011 (only from one of the plants), from three points of a UF-based treatment train. The wastewater samples were analyzed by measuring the BOD7, COD, TOC and total surface charge (TSC). The inorganic content and zeta potentials of the samples were analyzed and GC-FID/MS analyses were performed. The removal performances of BOD7, COD, TOC and TSC in 2008 and 2011 for both plants were very high. Initial concentrations of contaminants in 2011 were lower than in 2008, therefore the COD and TSC reductions were also lower in 2011 than three years before. Regardless of the high performance of UF-based processes in both plants, at times the residual concentrations were considerable. This could be explained by the high initial concentrations and also by the presence of the dissolved compounds that were characterized. Linear correlation was observed between COD and TOC, and between COD and TSC. The correlation between COD and TSC could be utilized for process control purposes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Kinetics and oxidative mechanism for H2O2-enhanced iron-mediated aeration (IMA) treatment of recalcitrant organic compounds in mature landfill leachate.

PubMed

Deng, Yang; Englehardt, James D

2009-09-30

A hydrogen peroxide (H(2)O(2))-enhanced iron (Fe(0))-mediated aeration (IMA) process has been recently demonstrated to effectively remove organic wastes from mature landfill leachate. In this paper, the kinetics and oxidative mechanisms of the enhanced IMA treatment were studied. Bench-scale full factorial tests were conducted in an orbital shaker reactor for treatment of a mature leachate with an initial chemical oxygen demand (COD) of 900-1200 mg/L. At the maximum aeration rate (8.3 mL air/min mL sample), process variables significantly influencing the rates of H(2)O(2) decay and COD removal were pH (3.0-8.0), initial H(2)O(2) doses (0.21-0.84 M), and Fe(0) surface area concentrations (0.06-0.30 m(2)/L). Empirical kinetic models were developed and verified for the degradation of H(2)O(2) and COD. High DO maintained by a high aeration rate slowed the H(2)O(2) self-decomposition, accelerated Fe(0) consumption, and enhanced the COD removal. In hydroxyl radical (OH*) scavenging tests, the rate of removal of glyoxylic acid (target compound) was not inhibited by the addition of para-chlorobenzoic acid (OH* scavenger) at pH 7.0-7.5, ruling out hydroxyl radical as the principal oxidant in neutral-weakly basic solution. These experimental results show that this enhanced IMA technology is a potential alternative for the treatment of high strength recalcitrant organic wastewaters.

Contracaecum osculatum and other anisakid nematodes in grey seals and cod in the Baltic Sea: molecular and ecological links.

PubMed

Zuo, S; Kania, P W; Mehrdana, F; Marana, M H; Buchmann, K

2018-01-01

Populations of grey seals (Halichoerus grypus), sprats (Sprattus sprattus) and cod (Gadus morhua) in the Baltic Sea are relatively stationary. The present work, applying classical and molecular helminthological techniques, documents that seals and cod also share a common parasite, the anisakid nematode Contracaecum osculatum, which uses seals as the final host and fish as transport hosts. Sequencing mitochondrial genes (COX1 and COX2) in adult worms from seals and third-stage larvae from livers of Baltic fish (sprats and cod), showed that all gene variants occur in both seals and fish. Other anisakid nematodes Pseudoterranova decipiens and Anisakis simplex are also found in both seals and cod in the Baltic Sea, but at much lower rates. The Baltic grey seal population was left at a critically low level (comprising a few hundred individuals) during the latter part of the 20th century, but since the year 2000 a marked increase in the population has been observed, reaching more than 40,000 individuals at present. Ecological consequences of the increased seal abundance may result from increased predation on fish stocks, but recent evidence also points to the influence of elevated parasitism on fish performance. Contracaecum osculatum larvae preferentially infect the liver of Baltic cod, considered a vital organ of the host. Whereas low prevalences and intensities in cod were reported during the 1980s and 1990s, the present study documents 100% prevalence and a mean intensity of above 80 worms per fish. Recent studies have also indicated the zoonotic potential of C. osculatum larvae in fish, following the consumption of raw or under-cooked fish. Therefore the present work discusses the impact of parasitism on the cod stock and the increasing risk for consumer health, and lists possible solutions for control.

Effect of in vitro and in vivo organotin exposures on the immune functions of murray cod (Maccullochella peelii peelii).

PubMed

Harford, Andrew J; O'Halloran, Kathryn; Wright, Paul E A

2007-08-01

Murray cod (Maccullochella peelii peelii) is an iconic native Australian freshwater fish and an ideal species for ecotoxicological testing of environmental pollutants. The species is indigenous to the Murray-Darling basin, which is the largest river system in Australia but also the ultimate sink for many environmental pollutants. The organotins tributyltin (TBT) and dibutyltin (DBT) are common pollutants of both freshwater and marine environments and are also known for their immunotoxicity in both mammals and aquatic organisms. In this study, TBT and DBT were used as exemplar immunotoxins to assess the efficiency of immune function assays (i.e., mitogen-stimulated lymphoproliferation, phagocytosis in head kidney tissue, and serum lysozyme activity) and to compare the sensitivity of Murray cod to other fish species. The organotins were lethal to Murray cod at concentrations previously reported as sublethal in rainbow trout (i.e., intraperitoneal [i.p.] lethal dose to 75% of the Murray cod [LD75] = 2.5 mg/kg DBT and i.p. lethal dose to 100% of the Murray cod [LD100] = 12.5 mg/kg TBT and DBT). In vivo TBT exposure at 0.1 and 0.5 mg/kg stimulated the phagocytic function of Murray cod (F = 6.89, df = 18, p = 0.004), while the highest concentration of 2.5 mg/kg TBT decreased lymphocyte numbers (F = 7.92, df = 18, p = 0.02) and mitogenesis (F = 3.66, df = 18, p = 0.035). Dibutyltin was the more potent immunosuppressant in Murray cod, causing significant reductions in phagocytic activity (F = 5.34, df = 16, p = 0.013) and lymphocyte numbers (F = 10.63, df = 16, p = 0.001).

Feasibility of nitrification/denitrification in a sequencing batch biofilm reactor with liquid circulation applied to post-treatment.

PubMed

Andrade do Canto, Catarina Simone; Rodrigues, José Alberto Domingues; Ratusznei, Suzana Maria; Zaiat, Marcelo; Foresti, Eugênio

2008-02-01

An investigation was performed on the biological removal of ammonium nitrogen from synthetic wastewater by the simultaneous nitrification/denitrification (SND) process, using a sequencing batch biofilm reactor (SBBR). System behavior was analyzed as to the effects of sludge type used as inoculum (autotrophic/heterotrophic), wastewater feed strategy (batch/fed-batch) and aeration strategy (continuous/intermittent). The presence of an autotrophic aerobic sludge showed to be essential for nitrification startup, despite publications stating the existence of heterotrophic organisms capable of nitrifying organic and inorganic nitrogen compounds at low dissolved oxygen concentrations. As to feed strategy, batch operation (synthetic wastewater containing 100 mg COD/L and 50 mg N-NH(4)(+)/L) followed by fed-batch (synthetic wastewater with 100 mg COD/L) during a whole cycle seemed to be the most adequate, mainly during the denitrification phase. Regarding aeration strategy, an intermittent mode, with dissolved oxygen concentration of 2.0mg/L in the aeration phase, showed the best results. Under these optimal conditions, 97% of influent ammonium nitrogen (80% of total nitrogen) was removed at a rate of 86.5 mg N-NH(4)(+)/Ld. In the treated effluent only 0.2 mg N-NO(2)(-)/L,4.6 mg N-NO(3)(-)/L and 1.0 mg N-NH(4)(+)/L remained, demonstrating the potential viability of this process in post-treatment of wastewaters containing ammonium nitrogen.

Electro-Fenton oxidation of reverse osmosis concentrate from sanitary landfill leachate: Evaluation of operational parameters.

PubMed

Fernandes, Annabel; Labiadh, Lazhar; Ciríaco, Lurdes; Pacheco, Maria José; Gadri, Abdellatif; Ammar, Salah; Lopes, Ana

2017-10-01

The electro-Fenton oxidation of a concentrate from reverse osmosis of a sanitary landfill leachate, with an initial chemical oxygen demand (COD) of 42 g L -1 , was carried out using a carbon-felt cathode and a boron doped diamond anode. The influence of the applied current intensity, initial pH and dissolved iron initial concentration on the electro-Fenton process was assessed. For the experimental conditions used, results showed that the initial pH is the parameter that more strongly influences the current efficiency of the electro-Fenton process, being this influence more pronounced on the oxidation rate than on the mineralization rate of the organic matter. The increase in iron initial concentration was found to be detrimental, since the natural amount of iron present in the effluent, 73 mg L -1 of total iron and 61 mg L -1 of dissolved iron, was sufficient to ensure the electro-Fenton process at the applied intensities - 0.2-1.4 A. For the more favourable conditions studied, initial pH of 3 and natural iron concentration, it was found an increase in the organic load and nitrogen removals with the applied current intensity. For the highest current intensity applied, a COD removal of 16.7 g L -1 was achieved after 8-h experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of a joint recirculation of concentrated leachate and leachate to landfills with a microaerobic bioreactor for leachate treatment.

PubMed

He, Ruo; Wei, Xiao-Meng; Tian, Bao-Hu; Su, Yao; Lu, Yu-Lan

2015-12-01

With comparison of a traditional landfill, a joint recirculation of concentrated leachate and leachate to landfills with or without a microaerobic reactor for leachate treatment was investigated in this study. The results showed that the joint recirculation of concentrated leachate and leachate with a microaerobic reactor for leachate treatment could not only utilize the microaerobic reactor to buffer the fluctuation of quality and quantity of leachate during landfill stabilization, but also reduce the inhibitory effect of acidic pH and high concentrations of ammonium in recycled liquid on microorganisms and accelerate the degradation of landfilled waste. After 390 days of operation, the discharge of COD and total nitrogen (TN) from the landfill with leachate pretreatment by a microaerobic reactor was 7.4 and 0.9 g, respectively, which accounted for 0.7% and 2.6% of COD, 1.9% and 7.5% of the TN discharge from the landfills without recirculation and directly recirculated with leachate and concentrated leachate, respectively. The degradation of the organic matter and biodegradable matter (BDM) in the landfill reactors could fit well with the first-order kinetics. The highest degradation of the organic matter and BDM was observed in the joint recirculation system with a microaerobic reactor for leachate treatment with the degradation constant of the first-order kinetics of 0.001 and 0.002. Copyright © 2015 Elsevier Ltd. All rights reserved.

A procedure to estimate proximate analysis of mixed organic wastes.

PubMed

Zaher, U; Buffiere, P; Steyer, J P; Chen, S

2009-04-01

In waste materials, proximate analysis measuring the total concentration of carbohydrate, protein, and lipid contents from solid wastes is challenging, as a result of the heterogeneous and solid nature of wastes. This paper presents a new procedure that was developed to estimate such complex chemical composition of the waste using conventional practical measurements, such as chemical oxygen demand (COD) and total organic carbon. The procedure is based on mass balance of macronutrient elements (carbon, hydrogen, nitrogen, oxygen, and phosphorus [CHNOP]) (i.e., elemental continuity), in addition to the balance of COD and charge intensity that are applied in mathematical modeling of biological processes. Knowing the composition of such a complex substrate is crucial to study solid waste anaerobic degradation. The procedure was formulated to generate the detailed input required for the International Water Association (London, United Kingdom) Anaerobic Digestion Model number 1 (IWA-ADM1). The complex particulate composition estimated by the procedure was validated with several types of food wastes and animal manures. To make proximate analysis feasible for validation, the wastes were classified into 19 types to allow accurate extraction and proximate analysis. The estimated carbohydrates, proteins, lipids, and inerts concentrations were highly correlated to the proximate analysis; correlation coefficients were 0.94, 0.88, 0.99, and 0.96, respectively. For most of the wastes, carbohydrate was the highest fraction and was estimated accurately by the procedure over an extended range with high linearity. For wastes that are rich in protein and fiber, the procedure was even more consistent compared with the proximate analysis. The new procedure can be used for waste characterization in solid waste treatment design and optimization.

Bacteria in non-woven textile filters for domestic wastewater treatment.

PubMed

Spychała, Marcin; Starzyk, Justyna

2015-01-01

The objective of this study was preliminary identification of heterotrophic and ammonia oxidizing bacteria (AOB) cell concentration in the cross-sectional profile of geotextile filters for wastewater treatment. Filters of thicknesses 3.6 and 7.2 mm, made of non-woven textile TS20, were supplied with septic tank effluent and intermittently dosed and filtered under hydrostatic pressure. The cumulative loads of chemical oxygen demand (COD) and total solids were about 1.36 and 1.06 kg/cm2, respectively. The filters under analysis reached a relatively high removal efficiency for organic pollution 70-90% for biochemical oxygen demand (BOD5) and 60-85% for COD. The ammonia nitrogen removal efficiency level proved to be unstable (15-55%). Biomass samples for dry mass identification were taken from two regions: continuously flooded with wastewater and intermittently flooded with wastewater. The culturable heterotrophic bacteria were determined as colony-forming units (CFUs) on microbiological-selective media by means of the plate method. AOB and nitrite oxidizing bacteria (NOB) were examined using the FISH technique. A relatively wide range of heterotrophic bacteria was observed from 7.4×10(5)/cm2 to 3.8×10(6)/cm2 in geotextile layers. The highest concentration of heterotrophic bacteria (3.8×10(6)/cm2) was observed in the first layer of the textile filter. AOB were identified occasionally--about 8-15% of all bacteria colonizing the last filter layer, but occasionally much higher concentrations and ammonia nitrogen efficiency were achieved. Bacteria oxidizing nitrite to nitrate were not observed. The relation of total and organic fraction of biomass to culturable heterotrophic bacteria was also found.

[Feasibility study on coke wastewater treatment using membrane bioreactor (MBR) system with complete sludge retention].

PubMed

Zhao, Wen-Tao; Huang, Xia; Lee, Duu-Jong; He, Miao; Yuan, Yuan

2009-11-01

A laboratory-scale submerged anaerobic-anoxic-oxic membrane bioreactor (A1/A2/O-MBR) system was used to treat real coke wastewater and operated continuously for 160 d with complete sludge retention. Pollutants removal performance of the system was investigated through long-term operation. The characteristics of dissolved organic matters (DOMs) in influent and effluent coke wastewater were analyzed using hydrophilic/hydrophobic fractionation, and further discussed based on fluorescence excitation-emission-matrix (EEM). The results showed that A1/A2/O-MBR system could stably remove 88.0% +/- 1.6% of COD, > 99.9% of volatile phenol, 99.4% +/- 0.2% of turbidity, and 98.3% +/- 1.9% of NH4(+) -N, with individual average effluent concentrations of 249 mg/L +/- 44 mg/L, 0.18 mg/L +/- 0.05 mg/L, 1.0 NTU +/- 0.2 NTU and 4.1 mg/L +/- 4.3 mg/L, respectively; moreover, the maximum TN removal rate also reached 74.9%. During the whole operation period, the MLVSS/MLSS appeared to be constant as 90.2% +/- 1.0% and no inorganic matters accumulation occurred. The observed sludge production (MLVSS/COD) decreased with time and stabilized at 0.035 kg/kg. DOMs in coke wastewater were fractionated as hydrophobic acids (HOA), hydrophobic neutrals (HON), hydrophobic bases (HOB) and hydrophilic substances (HIS); HOA was found to be the most abundant constituent in terms of DOC and color intensity both in influent and effluent, which accounted for 70% and 67% of total DOC, and 75% and 76% of total color intensity, respectively. Humic-like substances were suggested to be the major refractory organic and color-causing compounds coke wastewater effluent according to EEM analysis.

[Purification of waste water from olive-oil pressing plants using hydrophytes. Preliminary study on the use of Eichornia crassipes].

PubMed

Ferrara, L; Forgione, P; Schettino, O; Rullo, V

1989-04-01

The use of Eichornia crassipes has been tested in order to depurate the waste water from olive oil factories. The control of some parameter variations during the treatment, such as COD, total azote, dissolved oxygen and pH, has given encouraging results about the depurative efficacy of employed hydrophytae. Particularly indicative is, in this regard, COD rejection of about 60%.

Improving alachlor biodegradability by ferrate oxidation.

PubMed

Zhu, Jian-Hang; Yan, Xi-Luan; Liu, Ye; Zhang, Bao

2006-07-31

Alachlor can be recalcitrant when present at high concentrations in wastewater. Ferrate oxidation was used as a pretreatment to improve its biodegradability and was evaluated by monitoring alachlor elimination and removal of COD(Cr) (chemical oxygen demand determined by potassium dichromate) during the oxidation process up to a value compatible with biological treatment. Ferrate oxidation resulted in elimination of alachlor followed by degradation of its intermediates. High pH suppressed alachlor removal and COD(Cr) removal due to the low redox potential of ferrate ions. Although alachlor can be totally eliminated within 10 min under optimized conditions (alachlor, 40 mg l(-1); ferrate:alachlor molar ratio, 2; and pH 7.0), its complete mineralization cannot be achieved by ferrate oxidation alone. Alachlor solution treated by ferrate for 10 min inhibited an up-flow biotreatment with activated sludge. The biodegradability of ferrate-pretreated solution improved when the treatment was increased to 20 min, at the point of which BOD(5)/COD(Cr) ratio of the treated solution was increased to 0.87 from 0.35 after 10 min treatment. Under optimized conditions, ferrate oxidation for 20 min resulted in total elimination of alachlor, partial removal of COD(Cr) and the ferrate-treated solution could be effectively treated by the up-flow activated sludge process.

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

Fazeli, M.S.; Sathyanarayan, S.; Satish, P.N.

Physicochemical characteristics of wastewater from one of the paper mills near Nanjangud and the differential accumulation of heavy metals in parts of coconut trees growing in the area irrigated directly by the wastewaters of a paper mill were investigated. The total dissolved and suspended oils of wastewater were 1,136.9 mg/l and 2,185.4 mg/l, respectively. Biological oxygen demand (BOD) expands and COD is beyond the tolerance limit proposed by Indian standards. The concentrations of heavy meals like Cu, Pb, Zn, Ni, Coo, and Cd in coconut water, root, and leaf are higher than the limits suggested by World Health Organization. Survivalmore » of coconut trees irrigated by polluted waters indicates tolerance to toxic heavy metals. Since coconut forms part of human food chain, accumulation of toxic heavy metals may lead to organic disorders.« less

The significance of denitrifying polyphosphate accumulating organisms in biological nutrient removal activated sludge systems.

PubMed

Hu, Z R; Wentzel, M C; Ekama, G A

2002-01-01

In this paper the advantages and disadvantages of denitrifying PAOs (polyphosphate accumulating organisms) in conventional BNRAS (biological nutrient removal activated sludge) and external nitrification BNRAS (ENBNRAS) systems are evaluated, with experimental data exhibiting a range of anoxic P uptake from low (<10%) to very high (>60%). The results indicate that the specific denitrification rate of the PAOs on internally stored PHB COD is about 1/5th of that of the "ordinary" heterotrophic organisms on SBCOD, and the PAOs contribute little (maximum 20%) to the denitrification in BNRAS systems even when the anoxic P uptake is high (60% of the total P uptake). Considering the unpredictable nature of anoxic P uptake and the reduction in BEPR it causes compared with aerobic P uptake BEPR, it is concluded that anoxic P uptake does not add a significant advantage to the BNR system.

Case studies on the physical-chemical parameters' variation during three different purification approaches destined to treat wastewaters from food industry.

PubMed

Ghimpusan, Marieta; Nechifor, Gheorghe; Nechifor, Aurelia-Cristina; Dima, Stefan-Ovidiu; Passeri, Piero

2017-12-01

The paper presents a set of three interconnected case studies on the depuration of food processing wastewaters by using aeration & ozonation and two types of hollow-fiber membrane bioreactor (MBR) approaches. A secondary and more extensive objective derived from the first one is to draw a clearer, broader frame on the variation of physical-chemical parameters during the purification of wastewaters from food industry through different operating modes with the aim of improving the management of water purification process. Chemical oxygen demand (COD), pH, mixed liquor suspended solids (MLSS), total nitrogen, specific nitrogen (NH 4 + , NO 2 - , NO 3 - ) total phosphorous, and total surfactants were the measured parameters, and their influence was discussed in order to establish the best operating mode to achieve the purification performances. The integrated air-ozone aeration process applied in the second operating mode lead to a COD decrease by up to 90%, compared to only 75% obtained in a conventional biological activated sludge process. The combined purification process of MBR and ozonation produced an additional COD decrease of 10-15%, and made the Total Surfactants values to comply to the specific legislation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of the response of Atlantic cod ( Gadus morhua) in the high-latitude regions of the North Atlantic during the warm periods of the 1920s-1960s and the 1990s-2000s

NASA Astrophysics Data System (ADS)

Drinkwater, Ken

2009-10-01

Concern about future anthropogenic warming has lead to demands for information on what might happen to fish and fisheries under various climate-change scenarios. One suggestion has been to use past events as a proxy for what will happen in the future. In this paper a comparison between the responses of Atlantic cod ( Gadus morhua) to two major warm periods in the North Atlantic during the 20th century is carried out to determine how reliable the past might be as a predictor of the future. The first warm period began during the 1920s, remained relatively warm through the 1960s, and was limited primarily to the northern regions (>60°N). The second warm period, which again covered the northern regions but also extended farther south (30°N), began in the 1990s and has continued into the present century. During the earlier warm period, the most northern of the cod stocks (West Greenland, Icelandic, and Northeast Arctic cod in the Barents Sea) increased in abundance, individual growth was high, recruitment was strong, and their distribution spread northward. Available plankton data suggest that these cod responses were driven by bottom-up processes. Fishing pressure increased during this period of high cod abundance and the northern cod stocks began to decline, as early as the 1950s in the Barents Sea but during the 1960s elsewhere. Individual growth declined as temperatures cooled and the cod distributions retracted southward. During the warming in the 1990s, the spawning stock biomass of cod in the Barents Sea again increased, recruitment rose, and the stock spread northward, but the individual growth did not improve significantly. Cod off West Greenland also have shown signs of improving recruitment and increasing biomass, albeit they are still very low in comparison to the earlier warming period. The abundance of Icelandic cod, on the other hand, has remained low through the recent warm period and spawning stock biomass and total biomass are at levels near the lowest on record. The different responses of cod to the two warm events, in particular the reduced cod production during the recent warm period, are attributed to the effects of intense fishing pressure and possibly related ecosystem changes. The implications of the results of the comparisons on the development of cod scenarios under future climate change are addressed.

Combined organic matter and nitrogen removal from a chemical industry wastewater in a two-stage MBBR system.

PubMed

Cao, S M S; Fontoura, G A T; Dezotti, M; Bassin, J P

2016-01-01

Pesticide-producing factories generate highly polluting wastewaters containing toxic and hazardous compounds which should be reduced to acceptable levels before discharge. In this study, a chemical industry wastewater was treated in a pre-denitrification moving-bed biofilm reactor system subjected to an increasing internal mixed liquor recycle ratio from 2 to 4. Although the influent wastewater characteristics substantially varied over time, the removal of chemical oxygen demand (COD) and dissolved organic carbon was quite stable and mostly higher than 90%. The highest fraction of the incoming organic matter was removed anoxically, favouring a low COD/N environment in the subsequent aerobic nitrifying tank and thus ensuring stable ammonium removal (90-95%). However, during pH and salt shock periods, nitrifiers were severely inhibited but gradually restored their full nitrifying capability as non-stressing conditions were reestablished. Besides promoting an increase in the maximum nitrification potential of the aerobic attached biomass from 0.34 to 0.63 mg [Formula: see text], the increase in the internal recycle ratio was accompanied by an increase in nitrogen removal (60-78%) and maximum specific denitrification rate (2.7-3.3 mg NOx(-)--N). Total polysaccharides (PS) and protein (PT) concentrations of attached biomass were observed to be directly influenced by the influent organic loading rate, while the PS/PT ratio mainly ranged from 0.3 to 0.5. Results of Microtox tests showed that no toxicity was found in the effluent of both the anoxic and aerobic reactors, indicating that the biological process was effective in removing residual substances which might adversely affect the receiving waters' ecosystem.

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.

Development of downflow hanging sponge (DHS) reactor as post treatment of existing combined anaerobic tank treating natural rubber processing wastewater.

PubMed

Watari, Takahiro; Cuong Mai, Trung; Tanikawa, Daisuke; Hirakata, Yuga; Hatamoto, Masashi; Syutsubo, Kazuaki; Fukuda, Masao; Nguyen, Ngoc Bich; Yamaguchi, Takashi

2017-01-01

Conventional aerated tank technology is widely applied for post treatment of natural rubber processing wastewater in Southeast Asia; however, a long hydraulic retention time (HRT) is required and the effluent standards are exceeded. In this study, a downflow hanging sponge (DHS) reactor was installed as post treatment of anaerobic tank effluent in a natural rubber factory in South Vietnam and the process performance was evaluated. The DHS reactor demonstrated removal efficiencies of 64.2 ± 7.5% and 55.3 ± 19.2% for total chemical oxygen demand (COD) and total nitrogen, respectively, with an organic loading rate of 0.97 ± 0.03 kg-COD m -3 day -1 and a nitrogen loading rate of 0.57 ± 0.21 kg-N m -3 day -1 . 16S rRNA gene sequencing analysis of the sludge retained in the DHS also corresponded to the result of reactor performance, and both nitrifying and denitrifying bacteria were detected in the sponge carrier. In addition, anammox bacteria was found in the retained sludge. The DHS reactor reduced the HRT of 30 days to 4.8 h compared with the existing algal tank. This result indicates that the DHS reactor could be an appropriate post treatment for the existing anaerobic tank for natural rubber processing wastewater treatment.

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.

Two-stage soil infiltration treatment system for treating ammonium wastewaters of low COD/TN ratios.

PubMed

Lei, Zhongfang; Wu, Ting; Zhang, Yi; Liu, Xiang; Wan, Chunli; Lee, Duu-Jong; Tay, Joo-Hwa

2013-01-01

Soil infiltration treatment (SIT) is ineffective to treat ammonium wastewaters of total nitrogen (TN) > 100 mg l(-1). This study applied a novel two-stage SIT process for effective TN removal from wastewaters of TN>100 mg l(-1) and of chemical oxygen demand (COD)/TN ratio of 3.2-8.6. The wastewater was first fed into the soil column (stage 1) at hydraulic loading rate (HLR) of 0.06 m(3) m(-2) d(-1) for COD removal and total phosphorus (TP) immobilization. Then the effluent from stage 1 was fed individually into four soil columns (stage 2) at 0.02 m(3) m(-2) d(-1) of HLR with different proportions of raw wastewater as additional carbon source. Over the one-year field test, balanced nitrification and denitrification in the two-stage SIT revealed excellent TN removal (>90%) from the tested wastewaters. Copyright © 2012 Elsevier Ltd. All rights reserved.

Full-scale treatment of wastewater from a biodiesel fuel production plant with alkali-catalyzed transesterification.

PubMed

De Gisi, Sabino; Galasso, Maurizio; De Feo, Giovanni

2013-01-01

The treatment of wastewater derived from a biodiesel fuel (BDF) production plant with alkali-catalyzed transesterification was studied at full scale. The investigated wastewater treatment plant consisted of the following phases: primary adsorption/coagulation/flocculation/sedimentation processes, biological treatment with the combination of trickling filter and activated sludge systems, secondary flocculation/sedimentation processes, and reverse osmosis (RO) system with spiral membranes. All the processes were developed in a continuous mode, while the RO experiment was performed with batch tests. Two types of BDF wastewater were considered: the first wastewater (WW1) had an average total chemical oxygen demand (COD), pH and feed flow rate of 10,850.8 mg/L, 5.9 and 2946.7 L/h, respectively, while the second wastewater (WW2) had an average total COD, pH and feed flow rate of 43,898.9 mg/L, 3.3 and 2884.6 L/h, respectively. The obtained results from the continuous tests showed a COD removal percentage of more than 90% for the two types of wastewater considered. The removal of biorefractory COD and salts was obtained with a membrane technology in order to reuse the RO permeate in the factory production cycle. The rejections percentage of soluble COD, chlorides and sulphates were 92.8%, 95.0% and 99.5%, respectively. Because the spiral membranes required a high number of washing cycles, the use of plane membranes was preferable. Finally, the RO reject material should be evaporated using the large amount of inexpensive heat present in this type of industry.

[Total pollution features of urban runoff outlet for urban river].

PubMed

Luo, Hong-Bing; Luo, Lin; Huang, Gu; He, Qiang; Liu, Ping

2009-11-01

The urban stormwater runoff discharged to urban river, especially to rainfall source river, cannot be ignored. In this study, the Futian River watershed in Shenzhen city in a typical southern city of China is taken as the research object. In order to guide the pollution control for urban river, the eighteen rainfall events were monitored, and the total pollution features of the urban runoff outlet for this urban river were analyzed and discussed by using the process of pollutographs, the identifying to first flush, event mean concentration (EMC), etc. Results show that the concentrations of COD, SS, TN, TP and BOD5 are ten times more than the grade V of the environmental quality standards for surface water during the runoff time; the pollution caused by heavy metals (Cr, Ge, Cu, Hg and As) in runoff at a typical rainfall event is serious; the average and range of pollutant concentration at this runoff outlet in study area are evidently higher than at Shapingba in Chongqing city of China and at Silerwood in Canada, but are lower than at Shilipu in Wuhan city of China. The first flushes of COD, SS, BOD5, especially COD and SS, are evident, but the TN and TP are not. The average EMC of COD, TN, TP and BOD5 are 224.14, 571.15, 5.223, 2.04, 143.5 mg/L, respectively. To some extent, the EMC of COD is about two times of the value of the near cities, Macao and Zhuhai. The EMC of TN and TP are obviously higher than Beijing, Guangzhou and Shanghai. To compared with foreign counties, the EMC of the study area in Shenzhen is obviously much higher than the cities of Korean, USA and Canada. So the total pollution caused by the urban surface runoff in study area is serious and necessary to be treated.

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.

Sulfate addition as an effective method to improve methane fermentation performance and propionate degradation in thermophilic anaerobic co-digestion of coffee grounds, milk and waste activated sludge with AnMBR.

PubMed

Li, Qian; Li, Yu-You; Qiao, Wei; Wang, Xiaochang; Takayanagi, Kazuyuki

2015-06-01

This study was conducted to investigate the effects of sulfate on propionate degradation and higher organic loading rate (OLR) achievement in a thermophilic AnMBR for 373days using coffee grounds, milk and waste activated sludge (WAS) as the co-substrate. Without the addition of sulfate, the anaerobic system failed at an OLR of 14.6g-COD/L/d, with propionate accumulating to above 2.23g-COD/L, and recovery by an alkalinity supplement was not successful. After sulfate was added into substrates at a COD/SO4(2-) ratio of 200:1 to 350:1, biogas production increased proportionally with OLR increasing from 4.06 to 15.2g-COD/L/d. Propionic acid was maintained at less than 100mg-COD/L due to the effective conversion of propionic acid to methane after the sulfate supplement was added. The long-term stable performance of the AnMBR indicated that adding sulfate was beneficial for the degradation of propionate and achieving a higher OLR under the thermophilic condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Willingness to Know the Cause of Death and Hypothetical Acceptability of the Minimally Invasive Autopsy in Six Diverse African and Asian Settings: A Mixed Methods Socio-Behavioural Study

PubMed Central

Maixenchs, Maria; Anselmo, Rui; Zielinski-Gutiérrez, Emily; Odhiambo, Frank O.; Akello, Clarah; Zaidi, S. Shujaat H.; Soofi, Sajid Bashir; Bhutta, Zulfiqar A.; Diarra, Kounandji; Djitèye, Mahamane; Dembélé, Roukiatou; Sow, Samba; Minsoko, Pamela Cathérine Angoissa; Agnandji, Selidji Todagbe; Ismail, Mamudo R.; Carrilho, Carla; Ordi, Jaume; Menéndez, Clara; Bassat, Quique

2016-01-01

Background The minimally invasive autopsy (MIA) is being investigated as an alternative to complete diagnostic autopsies for cause of death (CoD) investigation. Before potential implementation of the MIA in settings where post-mortem procedures are unusual, a thorough assessment of its feasibility and acceptability is essential. Methods and Findings We conducted a socio-behavioural study at the community level to understand local attitudes and perceptions related to death and the hypothetical feasibility and acceptability of conducting MIAs in six distinct settings in Gabon, Kenya, Mali, Mozambique, and Pakistan. A total of 504 interviews (135 key informants, 175 health providers [including formal health professionals and traditional or informal health providers], and 194 relatives of deceased people) were conducted. The constructs “willingness to know the CoD” and “hypothetical acceptability of MIAs” were quantified and analysed using the framework analysis approach to compare the occurrence of themes related to acceptability across participants. Overall, 75% (379/504) of the participants would be willing to know the CoD of a relative. The overall hypothetical acceptability of MIA on a relative was 73% (366/504). The idea of the MIA was acceptable because of its perceived simplicity and rapidity and particularly for not “mutilating” the body. Further, MIAs were believed to help prevent infectious diseases, address hereditary diseases, clarify the CoD, and avoid witchcraft accusations and conflicts within families. The main concerns regarding the procedure included the potential breach of confidentiality on the CoD, the misperception of organ removal, and the incompatibility with some religious beliefs. Formal health professionals were concerned about possible contradictions between the MIA findings and the clinical pre-mortem diagnoses. Acceptability of the MIA was equally high among Christian and Islamic communities. However, in the two predominantly Muslim countries, MIA acceptability was higher in Mali than in Pakistan. While the results of the study are encouraging for the potential use of the MIA for CoD investigation in low-income settings, they remain hypothetical, with a need for confirmation with real-life MIA implementation and in populations beyond Health and Demographic Surveillance System areas. Conclusions This study showed a high level of interest in knowing the CoD of a relative and a high hypothetical acceptability of MIAs as a tool for CoD investigation across six distinct settings. These findings anticipate potential barriers and facilitators, both at the health facility and community level, essential for local tailoring of recommendations for future MIA implementation. PMID:27875532

Smart operation of nitritation/denitritation virtually abolishes nitrous oxide emission during treatment of co-digested pig slurry centrate.

PubMed

Peng, Lai; Carvajal-Arroyo, José M; Seuntjens, Dries; Prat, Delphine; Colica, Giovanni; Pintucci, Cristina; Vlaeminck, Siegfried E

2017-12-15

The implementation of nitritation/denitritation (Nit/DNit) as alternative to nitrification/denitrification (N/DN) is driven by operational cost savings, e.g. 1.0-1.8 EUR/ton slurry treated. However, as for any biological nitrogen removal process, Nit/DNit can emit the potent greenhouse gas nitrous oxide (N 2 O). Challenges remain in understanding formation mechanisms and in mitigating the emissions, particularly at a low ratio of organic carbon consumption to nitrogen removal (COD rem /N rem ). In this study, the centrate (centrifuge supernatant) from anaerobic co-digestion of pig slurry was treated in a sequencing batch reactor. The process removed approximately 100% of ammonium a satisfactory nitrogen loading rate (0.4 g N/L/d), with minimum nitrite and nitrate in the effluent. Substantial N 2 O emission (around 17% of the ammonium nitrogen loading) was observed at the baseline operational condition (dissolved oxygen, DO, levels averaged at 0.85 mg O 2 /L; COD rem /N rem of 2.8) with ∼68% of the total emission contributed by nitritation. Emissions increased with higher nitrite accumulation and lower organic carbon to nitrogen ratio. Yet, higher DO levels (∼2.2 mg O 2 /L) lowered the aerobic N 2 O emission and weakened the dependency on nitrite concentration, suggesting a shift in N 2 O production pathway. The most effective N 2 O mitigation strategy combined intermittent patterns of aeration, anoxic feeding and anoxic carbon dosage, decreasing emission by over 99% (down to ∼0.12% of the ammonium nitrogen loading). Without anaerobic digestion, mitigated Nit/DNit decreases the operational carbon footprint with about 80% compared to N/DN. With anaerobic digestion included, about 4 times more carbon is sequestered. In conclusion, the low COD rem /N rem feature of Nit/DNit no longer offsets its environmental sustainability provided the process is smartly operated. Copyright © 2017 Elsevier Ltd. All rights reserved.

More value from food waste: Lactic acid and biogas recovery.

PubMed

Kim, Mi-Sun; Na, Jeong-Geol; Lee, Mo-Kwon; Ryu, Hoyoung; Chang, Yong-Keun; Triolo, Jin M; Yun, Yeo-Myeong; Kim, Dong-Hoon

2016-06-01

Anaerobic digestion (AD) is one of the traditional technologies for treating organic solid wastes, but its economic benefit is sometimes questioned. To increase the economic feasibility of the treatment process, the aim of this study was to recover not only biogas from food waste but lactic acid (LA) as well. At first, LA fermentation of food waste (FW) was conducted using an indigenous mixed culture. During the operation, temperature was gradually increased from 35 °C to 55 °C, with the highest performance attained at 50 °C. At 50 °C and hydraulic retention time (HRT) of 1.0 d, LA concentration in the broth was 40 kg LA/m(3), corresponding to a yield of 1.6 mol LA/mol hexoseadded. Pyrosequencing results showed that Lactobacillus (97.6% of the total number of sequences) was the predominant species performing LA fermentation of FW. The fermented broth was then centrifuged and LA was extracted from the supernatant by the combined process of nanofiltration and water-splitting electrodialysis. The process could recover highly purified LA by removing 85% of mineral ions such as Na(+), K(+), Mg(2+), and Ca(2+) and 90% of residual carbohydrates. Meanwhile, the solid residue remained after centrifugation was further fermented to biogas by AD. At HRT 40 d (organic loading rate of 7 kg COD/m(3)/d), the highest volumetric biogas production rate of 3.5 m(3)/m(3)/d was achieved with a CH4 yield of 0.25 m(3) CH4/kg COD. The mass flow showed that 47 kg of LA and 54 m(3) of biogas could be recovered by the developed process from 1 ton of FW with COD removal efficiency of 70%. These products have a higher economic value 60 USD/ton FW compared to that of conventional AD (27 USD/ton FW). Copyright © 2016 Elsevier Ltd. All rights reserved.

[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.

Ocean Acidification Portends Acute Habitat Compression for Atlantic Cod (Gadus morhua) in a Physiologically-informed Metabolic Rate Model

NASA Astrophysics Data System (ADS)

Del Raye, G.; Weng, K.

2011-12-01

Ocean acidification affects organisms on a biochemical scale, yet its societal impacts manifest from changes that propagate through entire populations. Successful forecasting of the effects of ocean acidification therefore depends on at least two steps: (1) deducing systemic physiology based on subcellular stresses and (2) scaling individual physiology up to ecosystem processes. Predictions that are based on known biological processes (process-based models) may fare better than purely statistical models in both these steps because the latter are less robust to novel environmental conditions. Here we present a process-based model that uses temperature, pO2, and pCO2 to predict maximal aerobic scope in Atlantic cod. Using this model, we show that (i) experimentally-derived physiological parameters are sufficient to capture the response of cod aerobic scope to temperature and oxygen, and (ii) subcellular pH effects can be used to predict the systemic physiological response of cod to an acidified ocean. We predict that acute pH stress (on a scale of hours) could limit the mobility of Atlantic cod during diel vertical migration across a pCO2 gradient, promoting habitat compression. Finally, we use a global sensitivity analysis to identify opportunities for the improvement of model uncertainty as well as some physiological adaptations that could mitigate climate stresses on cod in the future.

Effect on Ca(OH)2 pretreatment to enhance biogas production of organic food waste

NASA Astrophysics Data System (ADS)

Junoh, H.; Yip, CH; Kumaran, P.

2016-03-01

This study investigated the effect of calcium hydroxide, Ca(OH)2 pretreatment in optimizing COD solubilisation and methane production through anaerobic digestion process. Two different parameters, chemical concentration (40-190 mEq/L) and pretreatment time (1-6 hours) were used to pretreat food waste. A central composite design and response surface methodology (RSM) was applied in obtaining the optimized condition for COD solubilisation. Result showed COD solubilisation was optimized at 166.98 mEq/L (equivalent to 6.1 g Ca(OH)2/L) for 1 hour. These conditions were applied through biomethane potential test with methane production of 864.19 mL/g VSdestructed and an increase of 20.0% as compared to untreated food waste.

Seasonal Temperature Estimates From Late Holocene Barents Sea cod Otoliths: Problems and Potential

NASA Astrophysics Data System (ADS)

Andersson, C.; Folkvord, A.; Geffen, A.; Høie, H.

2008-12-01

Realistic models of climate change require accurate data of past seasonal temperature regimes. In many marine settings this is difficult to achieve using the marine sedimentary record. This study tests the feasibility to use archaeological cod otoliths to reconstruct changes in the seasonal temperature cycle in the Barents Sea. Potentially, stable oxygen isotope records from cod otoliths could be used to produce records of Holocene temperature change on a seasonal time scale. Human settlements along the coast of northern Norway have exploited the cod (Gadus morhua) population of the Barents Sea from the earliest occupation, through the middle ages, to the present day. A pilot project has been carried out in Bergen to exploit the availability of a collection of cod otoliths from archeological excavations that is housed by the Bergen Museum. Cod otoliths from archaeological excavations in northern Norway, 26 specimens from from Måsøy (Finnmark) and 17 specimens from Vanna (Troms), were selected for this study. These specimens were AMS radiocarbon dated and the ages are spanning approximately 1400 to 1780 AD. Most of the otoliths are from cod that were captured during the Little Ice Age. Seasonal growth patterns were identifiable in the archeological otoliths, comparable to those in modern otoliths. Micromilling was used to sample for stable oxygen isotopes over a 2-year growth period in each of a total of 43 fossil cod otoliths. There are large differences in the temperature ranges experienced by the fish over the 2-year period analyzed. For the Måsøy specimens the temperature range experienced by the fish is between 2.7 to 9.9 °C. The Vanna cod experienced temperature ranges between 1.7 to 7.2 °C. The maximum temperature ranges for both Vanna and Måsøy specimens are higher than the seasonal instrumental measurements for the 0-200 m depth interval in the Kola section in the Barents Sea. The cod otoliths in our study have not yet been divided into different age groups, which is necessary in order to be able to interpret the calculated temperature ranges because the annual temperature cycles experienced by fish at different ages are different. Another problem that needs to address is the annual migration of cod of northern Norway. It is known that both mature and immature cod undertake long seasonal migrations.

The use of simulated rainfall to study the discharge process and the influence factors of urban surface runoff pollution loads.

PubMed

Qinqin, Li; Qiao, Chen; Jiancai, Deng; Weiping, Hu

2015-01-01

An understanding of the characteristics of pollutants on impervious surfaces is essential to estimate pollution loads and to design methods to minimize the impacts of pollutants on the environment. In this study, simulated rainfall equipment was constructed to investigate the pollutant discharge process and the influence factors of urban surface runoff (USR). The results indicated that concentrations of total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) appeared to be higher in the early period and then decreased gradually with rainfall duration until finally stabilized. The capacity and particle size of surface dust, rainfall intensity and urban surface slopes affected runoff pollution loads to a variable extent. The loads of TP, TN and COD showed a positive relationship with the surface dust capacity, whereas the maximum TSS load appeared when the surface dust was 0.0317 g·cm⁻². Smaller particle sizes (<0.125 mm) of surface dust generated high TN, TP and COD loads. Increases in rainfall intensity and surface slope enhanced the pollution carrying capacity of runoff, leading to higher pollution loads. Knowledge of the influence factors could assist in the management of USR pollution loads.

The Potential Applications of Real-Time Monitoring of Water Quality in a Large Shallow Lake (Lake Taihu, China) Using a Chromophoric Dissolved Organic Matter Fluorescence Sensor

PubMed Central

Niu, Cheng; Zhang, Yunlin; Zhou, Yongqiang; Shi, Kun; Liu, Xiaohan; Qin, Boqiang

2014-01-01

This study presents results from field surveys performed over various seasons in a large, eutrophic, shallow lake (Lake Taihu, China) using an in situ chromophoric dissolved organic matter (CDOM) fluorescence sensor as a surrogate for other water quality parameters. These measurements identified highly significant empirical relationships between CDOM concentration measured using the in situ fluorescence sensor and CDOM absorption, fluorescence, dissolved organic carbon (DOC), chemical oxygen demand (COD) and total phosphorus (TP) concentrations. CDOM concentration expressed in quinine sulfate equivalent units, was highly correlated with the CDOM absorption coefficient (r2 = 0.80, p < 0.001), fluorescence intensities (Ex./Em. 370/460 nm) (r2 = 0.91, p < 0.001), the fluorescence index (r2 = 0.88, p < 0.001) and the humification index (r2 = 0.78, p < 0.001), suggesting that CDOM concentration measured using the in situ fluorescence sensor could act as a substitute for the CDOM absorption coefficient and fluorescence measured in the laboratory. Similarly, CDOM concentration was highly correlated with DOC concentration (r2 = 0.68, p < 0.001), indicating that in situ CDOM fluorescence sensor measurements could be a proxy for DOC concentration. In addition, significant positive correlations were found between laboratory CDOM absorption coefficients and COD (r2 = 0.83, p < 0.001), TP (r2 = 0.82, p < 0.001) concentrations, suggesting a potential further application for the real-time monitoring of water quality using an in situ CDOM fluorescence sensor. PMID:24984060

The potential applications of real-time monitoring of water quality in a large shallow lake (Lake Taihu, China) using a chromophoric dissolved organic matter fluorescence sensor.

PubMed

Niu, Cheng; Zhang, Yunlin; Zhou, Yongqiang; Shi, Kun; Liu, Xiaohan; Qin, Boqiang

2014-06-30

This study presents results from field surveys performed over various seasons in a large, eutrophic, shallow lake (Lake Taihu, China) using an in situ chromophoric dissolved organic matter (CDOM) fluorescence sensor as a surrogate for other water quality parameters. These measurements identified highly significant empirical relationships between CDOM concentration measured using the in situ fluorescence sensor and CDOM absorption, fluorescence, dissolved organic carbon (DOC), chemical oxygen demand (COD) and total phosphorus (TP) concentrations. CDOM concentration expressed in quinine sulfate equivalent units, was highly correlated with the CDOM absorption coefficient (r(2) = 0.80, p < 0.001), fluorescence intensities (Ex./Em. 370/460 nm) (r(2) = 0.91, p < 0.001), the fluorescence index (r(2) = 0.88, p < 0.001) and the humification index (r(2) = 0.78, p < 0.001), suggesting that CDOM concentration measured using the in situ fluorescence sensor could act as a substitute for the CDOM absorption coefficient and fluorescence measured in the laboratory. Similarly, CDOM concentration was highly correlated with DOC concentration (r(2) = 0.68, p < 0.001), indicating that in situ CDOM fluorescence sensor measurements could be a proxy for DOC concentration. In addition, significant positive correlations were found between laboratory CDOM absorption coefficients and COD (r(2) = 0.83, p < 0.001), TP (r(2) = 0.82, p < 0.001) concentrations, suggesting a potential further application for the real-time monitoring of water quality using an in situ CDOM fluorescence sensor.