Evaluation of a Decentralized Wastewater Treatment Technology. INTERNATIONAL WASTEWATER SYSTEMS, INC. MODEL 6000 SEQUENCING BATCH REACTOR SYSTEM

EPA Science Inventory

Evaluation of the IWS Model 6000 SBR began in April 2004 when one SBR was taken off line and cleaned. The verification testing started July 1, 2004 and proceeded without interruption through June 30, 2005. All sixteen four-day sampling events were completed as scheduled, yielding...

An ecological vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment: system development, treatment performance, and mathematical modeling.

PubMed

Yuan, Jiajia; Dong, Wenyi; Sun, Feiyun; Li, Pu; Zhao, Ke

2016-05-01

An environment-friendly decentralized wastewater treatment process that is comprised of activated sludge process (ASP) and wetland vegetation, named as vegetation-activated sludge process (V-ASP), was developed for decentralized wastewater treatment. The long-term experimental results evidenced that the vegetation sequencing batch reactor (V-SBR) process had consistently stable higher removal efficiencies of organic substances and nutrients from domestic wastewater compared with traditional sequencing batch reactor (SBR). The vegetation allocated into V-SBR system could not only remove nutrients through its vegetation transpiration ratio but also provide great surface area for microorganism activity enhancement. This high vegetation transpiration ratio enhanced nutrients removal effectiveness from wastewater mainly by flux enhancement, oxygen and substrate transportation acceleration, and vegetation respiration stimulation. A mathematical model based on ASM2d was successfully established by involving the specific function of vegetation to simulate system performance. The simulation results on the influence of operational parameters on V-ASP treatment effectiveness demonstrated that V-SBR had a high resistance to seasonal temperature fluctuations and influent loading shocking.

Operation optimization of a photo-sequencing batch reactor for wastewater treatment: Study on influencing factors and impact on symbiotic microbial ecology.

PubMed

Ye, Jianfeng; Liang, Junyu; Wang, Liang; Markou, Giorgos; Jia, Qilong

2018-03-01

Wastewater treatment technology with better energy efficiency and recyclability is in urgent demand. Photo-Sequencing batch reactor (SBR), which introduces microalgae into conventional SBR, is considered to have more potential for resource recycling. In this study, a photo-SBR was evaluated through the manipulation of several key operational parameters, i.e., aeration strength, light supply intensity and time per cycle, and solid retention time (SRT). The algal-bacterial symbiotic system had the potential of removing COD, NH 4 + -N and TN with limited aeration, representing the advantage of energy-saving by low aeration requirement. Maintaining appropriate proportion of microalgae in the symbiotic system is critical for good system performance. Introducing microalgae into conventional SBR has obvious impact on the original microbial ecology. When the concentration of microalgae is too high (>4.60 mg Chl/L), the inhibition on certain phyla of bacteria, e.g., Bacteroidetes and Actinobacteria, would become prominent and not conducive to the stable operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of dissolved oxygen concentration on the start-up of the anammox-based process: ELAN®.

PubMed

Morales, N; Val del Río, A; Vázquez-Padín, J R; Gutiérrez, R; Fernández-González, R; Icaran, P; Rogalla, F; Campos, J L; Méndez, R; Mosquera-Corral, A

2015-01-01

The anammox-based process ELAN® was started-up in two different sequencing batch reactor (SBR) pilot plant reactors treating municipal anaerobic digester supernatant. The main difference in the operation of both reactors was the dissolved oxygen (DO) concentration in the bulk liquid. SBR-1 was started at a DO value of 0.4 mg O2/L whereas SBR-2 was started at DO values of 3.0 mg O2/L. Despite both reactors working at a nitrogen removal rate of around 0.6 g N/(L d), in SBR-1, granules represented only a small fraction of the total biomass and reached a diameter of 1.1 mm after 7 months of operation, while in SBR-2 the biomass was mainly composed of granules with an average diameter of 3.2 mm after the same operational period. Oxygen microelectrode profiling revealed that granules from SBR-2 where only fully penetrated by oxygen with DO concentrations of 8 mg O2/L while granules from SBR-1 were already oxygen penetrated at DO concentrations of 1 mg O2/L. In this way granules from SBR-2 performed better due to the thick layer of ammonia oxidizing bacteria, which accounted for up to 20% of all the microbial populations, which protected the anammox bacteria from non-suitable liquid media conditions.

Advanced phosphorus recovery using a novel SBR system with granular sludge in simultaneous nitrification, denitrification and phosphorus removal process.

PubMed

Lu, Yong-Ze; Wang, Hou-Feng; Kotsopoulos, Thomas A; Zeng, Raymond J

2016-05-01

In this study, a novel process for phosphorus (P) recovery without excess sludge production from granular sludge in simultaneous nitrification-denitrification and P removal (SNDPR) system is presented. Aerobic microbial granules were successfully cultivated in an alternating aerobic-anaerobic sequencing batch reactor (SBR) for removing P and nitrogen (N). Dense and stable granular sludge was created, and the SBR system showed good performance in terms of P and N removal. The removal efficiency was approximately 65.22 % for N, and P was completely removed under stable operating conditions. Afterward, new operating conditions were applied in order to enhance P recovering without excess sludge production. The initial SBR system was equipped with a batch reactor and a non-woven cloth filter, and 1.37 g of CH3COONa·3H2O was added to the batch reactor after mixing it with 1 L of sludge derived from the SBR reactor to enhance P release in the liquid fraction, this comprises the new system configuration. Under the new operating conditions, 93.19 % of the P contained in wastewater was released in the liquid fraction as concentrated orthophosphate from part of granular sludge. This amount of P could be efficiently recovered in the form of struvite. Meanwhile, a deterioration of the denitrification efficiency was observed and the granules were disintegrated into smaller particles. The biomass concentration in the system increased firstly and then maintained at 4.0 ± 0.15 gVSS/L afterward. These results indicate that this P recovery operating (PRO) mode is a promising method to recover P in a SNDPR system with granular sludge. In addition, new insights into the granule transformation when confronted with high chemical oxygen demand (COD) load were provided.

Study of the diversity of microbial communities in a sequencing batch reactor oxic-settling-anaerobic process and its modified process.

PubMed

Sun, Lianpeng; Chen, Jianfan; Wei, Xiange; Guo, Wuzhen; Lin, Meishan; Yu, Xiaoyu

2016-05-01

To further reveal the mechanism of sludge reduction in the oxic-settling-anaerobic (OSA) process, the polymerase chain reaction - denaturing gradient gel electrophoresis protocol was used to study the possible difference in the microbial communities between a sequencing batch reactor (SBR)-OSA process and its modified process, by analyzing the change in the diversity of the microbial communities in each reactor of both systems. The results indicated that the structure of the microbial communities in aerobic reactors of the 2 processes was very different, but the predominant microbial populations in anaerobic reactors were similar. The predominant microbial population in the aerobic reactor of the SBR-OSA belonged to Burkholderia cepacia, class Betaproteobacteria, while those of the modified process belonged to the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. These 3 types of microbes had a cryptic growth characteristic, which was the main cause of a greater sludge reduction efficiency achieved by the modified process.

Dynamic control of nutrient-removal from industrial wastewater in a sequencing batch reactor, using common and low-cost online sensors.

PubMed

Dries, Jan

2016-01-01

On-line control of the biological treatment process is an innovative tool to cope with variable concentrations of chemical oxygen demand and nutrients in industrial wastewater. In the present study we implemented a simple dynamic control strategy for nutrient-removal in a sequencing batch reactor (SBR) treating variable tank truck cleaning wastewater. The control system was based on derived signals from two low-cost and robust sensors that are very common in activated sludge plants, i.e. oxidation reduction potential (ORP) and dissolved oxygen. The amount of wastewater fed during anoxic filling phases, and the number of filling phases in the SBR cycle, were determined by the appearance of the 'nitrate knee' in the profile of the ORP. The phase length of the subsequent aerobic phases was controlled by the oxygen uptake rate measured online in the reactor. As a result, the sludge loading rate (F/M ratio), the volume exchange rate and the SBR cycle length adapted dynamically to the activity of the activated sludge and the actual characteristics of the wastewater, without affecting the final effluent quality.

Powdered ZELIAC augmented sequencing batch reactors (SBR) process for co-treatment of landfill leachate and domestic wastewater.

PubMed

Mojiri, Amin; Aziz, Hamidi Abdul; Zaman, Nastaein Q; Aziz, Shuokr Qarani; Zahed, Mohammad Ali

2014-06-15

Sequencing batch reactor (SBR) is one of the various methods of biological treatments used for treating wastewater and landfill leachate. This study investigated the treatment of landfill leachate and domestic wastewater by adding a new adsorbent (powdered ZELIAC; PZ) to the SBR technique. ZELIAC consists of zeolite, activated carbon, lime stone, rice husk ash, and Portland cement. The response surface methodology and central composite design were used to elucidate the nature of the response surface in the experimental design and describe the optimum conditions of the independent variables, including aeration rate (L/min), contact time (h), and ratio of leachate to wastewater mixture (%; v/v), as well as their responses (dependent variables). Appropriate conditions of operating variables were also optimized to predict the best value of responses. To perform an adequate analysis of the aerobic process, four dependent parameters, namely, chemical oxygen demand (COD), color, ammonia-nitrogen (NH3-N), and phenols, were measured as responses. The results indicated that the PZ-SBR showed higher performance in removing certain pollutants compared with SBR. Given the optimal conditions of aeration rate (1.74 L/min), leachate to wastewater ratio (20%), and contact time (10.31 h) for the PZ-SBR, the removal efficiencies for color, NH3-N, COD, and phenols were 84.11%, 99.01%, 72.84%, and 61.32%, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

On-site treatment of a motorway service area wastewater using a package sequencing batch reactor (SBR).

PubMed

Del Solar, J; Hudson, S; Stephenson, T

2005-01-01

A sequencing batch reactor (SBR) treating the effluent of a motorway service station in the south of England situated on a major tourist route was investigated. Wastewater from the kitchens, toilets and washrooms facilities was collected from the areas on each side of the motorway for treatment on-site. The SBR was designed for a population equivalent (p.e.) of 500, assuming an average flow of 100 m3/d, influent biochemical oxygen demand (BOD) of 300 mg/l, and influent suspended solids (SS) of 300 mg/l. Influent monitoring over 8 weeks revealed that the average flow was only 65 m3/d and the average influent BOD and SS were 480 mg/l and 473 mg/l respectively. This corresponded to a high sludge loading rate (F:M) of 0.42 d(-1) which accounted for poor performance. Therefore the cycle times were extended from 6 h to 7 h and effluent BOD improved from 79 to 27 mg/l.

Biodegradation of industrial-strength 2,4-dichlorophenoxyacetic acid wastewaters in the presence of glucose in aerobic and anaerobic sequencing batch reactors.

PubMed

Elefsiniotis, Panagiotis; Wareham, David G

2013-01-01

This research explored the biodegradability of 2,4-dichlorophenoxyacetic acid (2,4-D) in two laboratory-scale sequencing batch reactors (SBRs) that operated under aerobic and anaerobic conditions. The potential limit of 2,4-D degradation was investigated at a hydraulic retention time of 48 h, using glucose as a supplemental substrate and increasing feed concentrations of 2,4-D; namely 100 to 700 mg/L (i.e. industrial strength) for the aerobic system and 100 to 300 mg/L for the anaerobic SBR. The results revealed that 100 mg/L of 2,4-D was completely degraded following an acclimation period of 29 d (aerobic SBR) and 70 d (anaerobic SBR). The aerobic system achieved total 2,4-D removal at feed concentrations up to 600 mg/L which appeared to be a practical limit, since a further increase to 700 mg/L impaired glucose degradation while 2,4-D biodegradation was non-existent. In all cases, glucose was consumed before the onset of 2,4-D degradation. In the anaerobic SBR, 2,4-D degradation was limited to 120 mg/L.

ANAMMOX-like performances for nitrogen removal from ammonium-sulfate-rich wastewater in an anaerobic sequencing batch reactor.

PubMed

Prachakittikul, Pensiri; Wantawin, Chalermraj; Noophan, Pongsak Lek; Boonapatcharoen, Nimaradee

2016-01-01

Ammonium removal by the ANaerobic AMonium OXidation (ANAMMOX) process was observed through the Sulfate-Reducing Ammonium Oxidation (SRAO) process. The same concentration of ammonium (100 mg N L(-1)) was applied to two anaerobic sequencing batch reactors (AnSBRs) that were inoculated with the same activated sludge from the Vermicelli wastewater treatment process, while nitrite was fed in ANAMMOX and sulfate in SRAO reactors. In SRAO-AnSBR, in substrates that were fed with a ratio of NH4(+)/SO4(2-) at 1:0.4 ± 0.03, a hydraulic retention time (HRT) of 48 h and without sludge draining, the Ammonium Removal Rate (ARR) was 0.02 ± 0.01 kg N m(-3).d(-1). Adding specific ANAMMOX substrates to SRAO-AnSBR sludge in batch tests results in specific ammonium and nitrite removal rates of 0.198 and 0.139 g N g(-1) VSS.d, respectively, indicating that the ANAMMOX activity contributes to the removal of ammonium in the SRAO process using the nitrite that is produced from SRAO. Nevertheless, the inability of ANAMMOX to utilize sulfate to oxidize ammonium was also investigated in batch tests by augmenting enriched ANAMMOX culture in SRAO-AnSBR sludge and without nitrite supply. The time course of sulfate in a 24-hour cycle of SRAO-AnSBR showed an increase in sulfate after 6 h. For enriched SRAO culture, the uptake molar ratio of NH4(+)/SO4(2-) at 8 hours in a batch test was 1:0.82 lower than the value of 1:0.20 ± 0.09 as obtained in an SRAO-AnSBR effluent, while the stoichiometric ratio of 1:0.5 that includes the ANAMMOX reaction was in this range. After a longer operation of more than 2 years without sludge draining, the accumulation of sulfate and the reduction of ammonium removal were observed, probably due to the gradual increase in the sulfur denitrification rate and the competitive use of nitrite with ANAMMOX. The 16S rRNA gene PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and PCR cloning analyses resulted in the detection of the ANAMMOX bacterium (Candidatus Brocadia sinica JPN1) Desulfacinum subterraneum belonging to the genus Desulfacinum and bacteria that are involved in sulfur metabolism (Pseudomonas aeruginosa strain SBTPe-001 and Paracoccus denitrificans strain IAM12479) in SRAO-AnSBR.

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.

Biological Nitrogen Removal through Nitritation Coupled with Thiosulfate-Driven Denitritation

PubMed Central

Qian, Jin; Zhou, Junmei; Zhang, Zhen; Liu, Rulong; Wang, Qilin

2016-01-01

A novel biological nitrogen removal system based on nitritation coupled with thiosulfate-driven denitritation (Nitritation-TDD) was developed to achieve a high nitrogen removal rate and low sludge production. A nitritation sequential batch reactor (nitritation SBR) and an anoxic up-flow sludge bed (AnUSB) reactor were applied for effective nitritation and denitritation, respectively. Above 75% nitrite was accumulated in the nitritation SBR with an influent ammonia loading rate of 0.43 kg N/d/m3. During Nitritation-TDD operation, particle sizes (d50) of the sludge decreased from 406 to 225 um in nitritation SBR and from 327–183 um in AnUSB reactor. Pyrosequencing tests revealed that ammonium-oxidizing bacteria (AOB) population was stabilized at approximately 7.0% (calculated as population of AOB-related genus divided by the total microbial population) in the nitritation SBR. In contrast, nitrite-oxidizing bacteria (NOB) population decreased from 6.5–0.6% over the same time, indicating the effective nitrite accumulation in the nitritation SBR. Thiobacillus, accounting for 34.2% in the AnUSB reactor, was mainly responsible for nitrogen removal via autotrophic denitritation, using an external source of thiosulfate as electron donor. Also, it was found that free nitrous acid could directly affect the denitritation activity. PMID:27272192

Short-term Influence of Drilling Fluid on Ciliates from Activated Sludge in Sequencing Batch Reactors.

PubMed

Babko, Roman; Kuzmina, Tatiana; Łagód, Grzegorz; Jaromin-Gleń, Katarzyna; Danko, Yaroslav; Pawłowska, Małgorzata; Pawłowski, Artur

2017-01-01

Spent drilling muds are the liquid residues of rock drilling operations. Due to a high concentration of suspended solids and potentially detrimental chemical properties, they can negatively affect microorganisms participating in wastewater treatment processes. We evaluated the addition of a potassium-polymer drilling fluid (DF) to activated sludge in laboratory sequencing batch reactors (SBRs) for municipal wastewater treatment. Ciliate assemblage, the most dynamic component of eukaryotes in activated sludge, and which is highly sensitive to changes in the system, was evaluated. The average ciliate abundance dropped by about 51% (SBR 2; 1% DF added) and 33% (SBR 3; 3% DF added) in comparison to the control (SBR 1; wastewater only). A decrease in the total number of ciliate species during the experiment was observed, from 25 to 24 in SBR 2 and from 17 to 13 in SBR 3. Moreover, a drop in the number of dominant (>100 individuals mL) ciliate species was observed during the experiment-from eight in the control to five in SBR 2 and four in SBR 3-signaling noticeable changes in the quantitative structure of ciliate species. The species analyzed showed different responses to DF addition. The most sensitive was , which is bacteriovorus. In contrast, two predators, and , showed no reaction to DF addition. Our results indicate that addition of potassium-polymer DF, in doses of 1 to 3% of the treated wastewater volume, had no toxic effects on ciliates, but qualitative and quantitative changes in their community were observed. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

[Factors of the rapid startup for nitrosation in sequencing batch reactor].

PubMed

Li, Dong; Tao, Xiao-Xiao; Li, Zhan; Wang, Jun-An; Zhang, Jie

2011-08-01

The approach and factors for realizing the rapid startup of nitrosation were researched at the low level of dissolved oxygen (DO) in sequencing batch reactor (SBR). The main parameters of the reactor were controlled as follows: DO were 0.15-0.40 mg/L, pH values kept from 7.52 to 8.30, temperature maintained at 22.3-27.1 degrees C, and time of aeration was 8 hours. The purpose of rapid startup for nitrosation was achieved after 57 cycles (36 d) with the alternative influent of high and low ammonium wastewater (the mean values were 245.28 mg/L and 58.08 mg/L respectively) in a SBR, and the nitrosation rate was even 100%. Factors of accumulation of nitrite were investigated and the effects of DO and pH were analyzed during the startup for nitrosation. The results showed that it could improve the efficiency of nitrosation when DO concentration was increased appropriately. The activity of nitrite oxidizing bacteria (NOB) was recovered gradually when DO was higher than 0.72 mg/L. The key factor of controlling nitrosation reaction was the concentration of free ammonia (FA), while the final factor was the concentration of DO. pH was a desired controlling parameter to show the end of nitrification in a SBR cycle, while DO concentration did not indicate the finishing of SBR nitrification accurately because it increased rapidly before ammonia nitrogen was oxidized absolutely.

Optimization aspects of the biological nitrogen removal process in a full-scale twin sequencing batch reactor (SBR) system in series treating landfill leachate.

PubMed

Remmas, Nikolaos; Ntougias, Spyridon; Chatzopoulou, Marianna; Melidis, Paraschos

2018-03-29

Despite the fact that biological nitrogen removal (BNR) process has been studied in detail in laboratory- and pilot-scale sequencing batch reactor (SBR) systems treating landfill leachate, a limited number of research works have been performed in full-scale SBR plants regarding nitrification and denitrification. In the current study, a full-scale twin SBR system in series of 700 m 3 (350 m 3 each) treating medium-age landfill leachate was evaluated in terms of its carbon and nitrogen removal efficiency in the absence and presence of external carbon source, i.e., glycerol from biodiesel production. Both biodegradable organic carbon and ammonia were highly oxidized [biochemical oxygen demand (BOD 5 ) and total Kjehldahl nitrogen (TKN) removal efficiencies above 90%], whereas chemical oxygen demand (COD) removal efficiency was slightly above 40%, which is within the range reported in the literature for pilot-scale SBRs. As the consequence of the high recalcitrant organic fraction of the landfill leachate, dissimilatory nitrate reduction was restricted in the absence of crude glycerol, although denitrification was improved by electron donor addition, resulting in TN removal efficiencies above 70%. Experimental data revealed that the second SBR negligibly contributed to BNR process, since carbon and ammonia oxidation completion was achieved in the first SBR. On the other hand, the low VSS/SS ratio, due to the lack of primary sedimentation, highly improved sludge settleability, resulting in sludge volume indices (SVI) below 30 mL g -1 .

Heterotrophic denitrification plays an important role in N₂O production from nitritation reactors treating anaerobic sludge digestion liquor.

PubMed

Wang, Qilin; Jiang, Guangming; Ye, Liu; Pijuan, Maite; Yuan, Zhiguo

2014-10-01

Nitrous oxide (N2O) emissions from nitritation reactors receiving real anaerobic sludge digestion liquor have been reported to be substantially higher than those from reactors receiving synthetic digestion liquor. This study aims to identify the causes for the difference, and to develop strategies to reduce N2O emissions from reactors treating real digestion liquor. Two sequencing batch reactors (SBRs) performing nitritation, fed with real (SBR-R) and synthetic (SBR-S) digestion liquors, respectively, were employed. The N2O emission factors for SBR-R and SBR-S were determined to be 3.12% and 0.80% of the NH4(+)-N oxidized, respectively. Heterotrophic denitrification supported by the organic carbon present in the real digestion liquor was found to be the key contributor to the higher N2O emission from SBR-R. Heterotrophic nitrite reduction likely stopped at N2O (rather than N2), with a hypothesised cause being free nitrous acid inhibition. This implies that all nitrite reduced by heterotrophic bacteria was converted to and emitted as N2O. Increasing dissolved oxygen (DO) concentration from 0.5 to 1.0 mg/L, or above, decreased aerobic N2O production from 2.0% to 0.5% in SBR-R, whereas aerobic N2O production in SBR-S remained almost unchanged (at approximately 0.5%). We hypothesised that DO at 1 mg/L or above suppressed heterotrophic nitrite reduction thus reduced aerobic heterotrophic N2O production. We recommend that DO in a nitritation system receiving anaerobic sludge digestion liquor should be maintained at approximately 1 mg/L to minimise N2O emission. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of nitrogen removal rates and nitrous oxide production from enriched anaerobic ammonium oxidizing bacteria in suspended and attached growth reactors.

PubMed

Panwivia, Supaporn; Sirvithayapakorn, Sanya; Wantawin, Chalermraj; Noophan, Pongsak Lek; Munakata-Marr, Junko

2014-01-01

Attached growth-systems for the anaerobic ammonium oxidation (anammox) process have been postulated for implementation in the field. However, information about the anammox process in attached growth-systems is limited. This study compared nitrogen removal rates and nitrous oxide (N2O) production of enriched anammox cultures in both suspended and attached growth sequencing batch reactors (SBRs). Suspended growth reactors (SBR-S) and attached growth reactors using polystyrene sponge as a medium (SBR-A) were used in these experiments. After inoculation with an enriched anammox culture, significant nitrogen removals of ammonium (NH4 (+)) and nitrite (NO2 (-)) were observed under NH4 (+):NO2 (-) ratios ranging from 1:1 to 1:2 in both types of SBRs. The specific rates of total nitrogen removal in SBR-S and SBR-A were 0.52 mg N/mg VSS-d and 0.44 mg N/mg VSS-d, respectively, at an NH4 (+):NO2 (-) ratio of 1:2. N2O production by the enriched anammox culture in both SBR-S and SBR-A was significantly higher at NH4 (+):NO2 (-) ratio of 1:2 than at NH4 (+):NO2 (-) ratios of 1:1 and 1:1.32. In addition, N2O production was higher at a pH of 6.8 than at pH 7.3, 7.8, and 8.3 in both SBR-S and SBR-A. The results of this investigation demonstrate that the anammox process may avoid N2O emission by maintaining an NH4 (+):NO2 (-) ratio of less than 1:2 and pH higher than 6.8.

Combining SBR systems for chemical and biological treatment: the destruction of the nerve agent VX.

PubMed

Irvine, R L; Haraburda, S S; Galbis-Reig, C

2004-01-01

The US Army is pilot testing the neutralization of VX nerve agent stockpiled at Newport, Indiana using caustic hydrolysis in a Sequencing Batch Reactor (SBR). The resulting hydrolysate was tested at the bench-scale for treatment with activated sludge biodegradation in two distinct studies, one in the SBR and another, in the PACT process. The feed to both biological systems was pretreated to enhance the biodegradability of the hydrolysis products. Both biodegradation studies demonstrated that the hydrolysate could easily meet the Chemical Weapons Convention treaty and US environmental regulations following pretreatment.

Impact of partial nitritation degree and C/N ratio on simultaneous Sludge Fermentation, Denitrification and Anammox process.

PubMed

Wang, Bo; Peng, Yongzhen; Guo, Yuanyuan; Yuan, Yue; Zhao, Mengyue; Wang, Shuying

2016-11-01

This study presents a novel process (i.e. PN/SFDA) to remove nitrogen from low C/N domestic wastewater. The process mainly involves two reactors, a pre-Sequencing Batch Reactor for partial nitritation (termed as PN-SBR) and an anoxic reactor for integrated Denitrification and Anammox with carbon sources produced from Sludge Fermentation (termed as SFDA). During long-term Runs, NO2(-)/NH4(+) ratio (i.e. NO2(-)-N/NH4(+)-N calculated by mole) in the PN-SBR effluent was gradually increased from 0.2 to 37 by extending aerobic duration, meaning that partial nitritation turning to full nitritation could be achieved. Impact of partial nitritation degree on SFDA process was investigated and the result showed that, NO2(-)/NH4(+) ratios between 2 and 10 were appropriate for the co-existence of denitrification and anammox together in the SFDA reactor, and denitrification instead of anammox contributed greater for nitrogen removal. Further batch tests indicated that anammox collaborated well with denitrification at low C/N (1.0 in this study). Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Monitoring pH and electric conductivity in an EBPR sequencing batch reactor.

PubMed

Serralta, J; Borrás, L; Blanco, C; Barat, R; Seco, A

2004-01-01

This paper presents laboratory-scale experimentation carried out to study enhanced biological phosphorus removal. Two anaerobic aerobic (A/O) sequencing batch reactors (SBR) have been operated during more than one year to investigate the information provided by monitoring pH and electric conductivity under stationary and transient conditions. Continuous measurements of these parameters allow detecting the end of anaerobic phosphorus release, of aerobic phosphorus uptake and of initial denitrification, as well as incomplete acetic acid uptake. These results suggest the possibility of using pH and electric conductivity as control parameters to determine the length of both anaerobic and aerobic phases in an A/O SBR. More valuable information provided by monitoring pH and electric conductivity is the relation between the amount of phosphorus released and the conductivity increase observed during the anaerobic stages and which group of bacteria (heterotrophic or polyphosphate accumulating) is carrying out the denitrification process.

Evaluation of a sequencing batch reactor sewage treatment rig for investigating the fate of radioactively labelled pharmaceuticals: Case study of propranolol.

PubMed

Popple, T; Williams, J B; May, E; Mills, G A; Oliver, R

2016-01-01

Pharmaceuticals are frequently detected in the aquatic environment, and have potentially damaging effects. Effluents from sewage treatment plants (STPs) are major sources of these substances. The use of sequencing batch reactor (SBR) STPs, involving cycling between aerobic and anoxic conditions to promote nitrification and denitrification, is increasing but these have yet to be understood in terms of removal of pharmaceutical residues. This study reports on the development of a laboratory rig to simulate a SBR. The rig was used to investigate the fate of radiolabelled propranolol. This is a commonly prescribed beta blocker, but with unresolved fate in STPs. The SBR rig (4.5 L) was operated on an 8 h batch cycle with settled sewage. Effective treatment was demonstrated, with clearly distinct treatment phases and evidence of nitrogen removal. Radiolabelled (14)C-propranolol was dosed into both single (closed) and continuous (flow-through) simulations over 13 SBR cycles. Radioactivity in CO2 off-gas, biomass and liquid was monitored, along with the characteristics of the sewage. This allowed apparent rate constants and coefficients for biodegradation and solid:water partitioning to be determined. Extrapolation from off-gas radioactivity measurements in the single dose 4-d study suggested that propranolol fell outside the definitions of being readily biodegradable (DegT50 = 9.1 d; 60% biodegradation at 12.0 d). During continuous dosing, 63-72% of propranolol was removed in the rig, but less than 4% of dose recovered as (14)CO2, suggesting that biodegradation was a minor process (Kbiol(M) L kg d(-1) = 22-49) and that adsorption onto solids dominated, giving rise to accumulations within biomass during the 17 d solid retention time in the SBR. Estimations of adsorption isotherm coefficients were different depending on which of three generally accepted denominators representing sorption sites was used (mixed liquor suspended solids, reactor COD or mass of waste activated sludge). With further development and evaluation, the rig developed for simulating SBR processes has potential to be used for informing better environmental risk assessments for those pharmaceuticals showing ambiguous results in field fate studies. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The mechanism of enhanced wastewater nitrogen removal by photo-sequencing batch reactors based on comprehensive analysis of system dynamics within a cycle.

PubMed

Ye, Jianfeng; Liang, Junyu; Wang, Liang; Markou, Giorgos

2018-07-01

To understand the mechanism of enhanced nitrogen removal by photo-sequencing batch reactors (photo-SBRs), which incorporated microalgal photosynthetic oxygenation into the aerobic phases of a conventional cycle, this study performed comprehensive analysis of one-cycle dynamics. Under a low aeration intensity (about 0.02 vvm), a photo-SBR, illuminated with light at 92.27 μ·mol·m -2 ·s -1 , could remove 99.45% COD, 99.93% NH 4 + -N, 90.39% TN, and 95.17% TP, while the control SBR could only remove 98.36% COD, 83.51% NH 4 + -N, 78.96% TN, and 97.75% TP, for a synthetic domestic sewage. The specific oxygen production rate (SOPR) of microalgae in the photo-SBR could reach 6.63 fmol O 2 ·cell -1 ·h -1 . One-cycle dynamics shows that the enhanced nitrogen removal by photo-SBRs is related to photosynthetic oxygenation, resulting in strengthened nitrification, instead of direct nutrient uptake by microalgae. A too high light or aeration intensity could deteriorate anoxic conditions and thus adversely affect the removal of TN and TP in photo-SBRs. Copyright © 2018 Elsevier Ltd. All rights reserved.

NH4+ ad-/desorption in sequencing batch reactors: simulation, laboratory and full-scale studies.

PubMed

Schwitalla, P; Mennerich, A; Austermann-Haun, U; Müller, A; Dorninger, C; Daims, H; Holm, N C; Rönner-Holm, S G E

2008-01-01

Significant NH4-N balance deficits were found during the measurement campaigns for the data collection for dynamic simulation studies at five full-scale sequencing batch reactor (SBR) waste water treatment plants (WWTPs), as well as during subsequent calibrations at the investigated plants. Subsequent lab scale investigations showed high evidence for dynamic, cycle-specific NH4+ ad-/desorption to the activated flocs as one reason for this balance deficit. This specific dynamic was investigated at five full-scale SBR plants for the search of the general causing mechanisms. The general mechanism found was a NH4+ desorption from the activated flocs at the end of the nitrification phase with subsequent nitrification and a chemical NH4+ adsorption at the flocs in the course of the filling phases. This NH4+ ad-/desorption corresponds to an antiparallel K+ ad/-desorption.One reasonable full-scale application was investigated at three SBR plants, a controlled filling phase at the beginning of the sedimentation phase. The results indicate that this kind of filling event must be specifically hydraulic controlled and optimised in order to prevent too high waste water break through into the clear water phase, which will subsequently be discarded. IWA Publishing 2008.

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

PubMed

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

2013-05-01

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

Efficiency of wastewater treatment in SBR and IFAS-MBSBBR systems in specified technological conditions.

PubMed

Sytek-Szmeichel, K; Podedworna, J; Zubrowska-Sudol, M

2016-01-01

The objective of this study is to compare wastewater treatment effectiveness in sequencing batch reactor (SBR) and integrated fixed-film activated sludge-moving-bed sequencing batch biofilm reactor (IFAS-MBSBBR) systems in specific technological conditions. The comparison of these two technologies was based on the following assumptions, shared by both series, I and II: the reactor's active volume was 28 L; 8-hour cycle of reactor's work, with the same sequence and duration of its consecutive phases; and the dissolved oxygen concentration in the aerobic phases was maintained at a level of 3.0 mg O2/L. For both experimental series (I and II), comparable effectiveness of organic compound (chemical oxygen demand (COD)) removal, nitrification and biological phosphorus removal has been obtained at levels of 95.1%, 97% and 99%, respectively. The presence of the carrier improved the efficiency of total nitrogen removal from 86.3% to 91.7%. On the basis of monitoring tests, it has been found that the ratio of simultaneous denitrification in phases with aeration to the total efficiency of denitrification in the cycle was 1.5 times higher for IFAS-MBSBBR.

Membrane biofouling mechanism in an aerobic granular reactor degrading 4-chlorophenol.

PubMed

Buitrón, Germán; Moreno-Andrade, Iván; Arellano-Badillo, Víctor M; Ramírez-Amaya, Víctor

2014-01-01

The membrane fouling of an aerobic granular reactor coupled with a submerged membrane in a sequencing batch reactor (SBR) was evaluated. The fouling analysis was performed by applying microscopy techniques to determine the morphology and structure of the fouling layer on a polyvinylidene fluoride membrane. It was found that the main cause of fouling was the polysaccharide adsorption on the membrane surface, followed by the growth of microorganisms to form a biofilm.

A sequential treatment of intermediate tropical landfill leachate using a sequencing batch reactor (SBR) and coagulation.

PubMed

Yong, Zi Jun; Bashir, Mohammed J K; Ng, Choon Aun; Sethupathi, Sumathi; Lim, Jun-Wei

2018-01-01

The increase in landfill leachate generation is due to the increase of municipal solid waste (MSW) as global development continues. Landfill leachate has constantly been the most challenging issue in MSW management as it contains high amount of organic and inorganic compounds that might cause pollution to water resources. Biologically treated landfill leachate often fails to fulfill the regulatory discharge standards. Thus, to prevent environmental pollution, many landfill leachate treatment plants involve multiple stages treatment process. The Papan Landfill in Perak, Malaysia currently has no proper leachate treatment system. In the current study, sequential treatment via sequencing batch reactor (SBR) followed by coagulation was used to treat chemical oxygen demand (COD), ammoniacal nitrogen (NH 3 -N), total suspended solids (TSS), and colour from raw landfill leachate. SBR optimum aeration rate, L/min, optimal pH and dosage (g/L) of Alum for coagulation as a post-treatment were determined. The two-step sequential treatment by SBR followed by coagulation (Alum) achieved a removal efficiency of 84.89%, 94.25%, 91.82% and 85.81% for COD, NH 3 -N, TSS and colour, respectively. Moreover, the two-stage treatment process achieved 95.0% 95.0%, 95.3%, 100.0%, 87.2%, 62.9%, 50.0%, 41.3%, 41.2, 34.8, and 22.9 removals of Cadmium, Lead, Copper, Selenium, Barium, Iron, Silver, Nickel, Zinc, Arsenic, and Manganese, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bulking sludge for PHA production: energy saving and comparative storage capacity with well-settled sludge.

PubMed

Wen, Qinxue; Chen, Zhiqiang; Wang, Changyong; Ren, Nanqi

2012-01-01

Two acetate-fed sequencing batch reactors (SBR) were operated under an aerobic dynamic feeding (ADF) model (SBR#2) and with anaerobic phase before aerobic phase (SBR#1) to select mixed cultures with a high polyhydroxyalkanoates (PHA) storage response. Although kinetic selection based on storage response should bring about a predominance of floc-formers, a bulking sludge with storage response comparable to well-settled sludge was steadily established. An anaerobic phase was introduced before the aerobic phase in the ADF model to improve the sludge settleability (SBR #1), however, due to the consequent increased feast/famine ratio, the performance of SBR #1, in terms of both the maximum PHB (polyhydroxybutyrate) cell content and deltaPHB, was lower than that of SBR #2. SBR #2 gradually reached a steady state while SBR #1 failed suddenly after 50 days of operation. The maximum specific substrate uptake rate and storage rate for the selected bulking sludge were 0.4 Cmol Ac/(Cmol X x hr) and 0.18 Cmol Ac/(Cmol PHB x hr), respectively, resulting a yield of 0.45 Cmol PHB/(Cmol Ac) in SBR #2 in the culture enrichment phase. A maximum PHB content of 53% of total suspended solids and PHB storage rate of 1.36 Cmol Ac/(Cmol PHB x hr) was achieved at 10.2 hr in batch accumulation tests under nitrogen starvation. The results indicated that it was feasible to utilize filamentous bacteria to accumulate PHA with a rate comparable to well-settled sludge. Furthermore, the lower dissolved oxygen demand of filamentous bacteria would save energy required for aeration in the culture enrichment stage.

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.

The effect of anaerobic-aerobic and feast-famine cultivation pattern on bacterial diversity during poly-β-hydroxybutyrate production from domestic sewage sludge.

PubMed

Liu, Changli; Liu, Di; Qi, Yingjie; Zhang, Ying; Liu, Xi; Zhao, Min

2016-07-01

The main objective of this work was to investigate the influence of different oxygen supply patterns on poly-β-hydroxybutyrate (PHB) yield and bacterial community diversity. The anaerobic-aerobic (A/O) sequencing batch reactors (SBR1) and feast-famine (F/F) SBR2 were used to cultivate activated sludge to produce PHB. The mixed microbial communities were collected and analyzed after 3 months cultivation. The PHB maximum yield was 64 wt% in SBR1 and 53 wt% in SBR2. Pyrosequencing analysis 16S rRNA gene of two microbial communities indicated there were nine and four bacterial phyla in SBR1 and SBR2, respectively. Specifically, Proteobacteria (36.4 % of the total bacterial community), Actinobacteria (19.7 %), Acidobacteria (14.1 %), Firmicutes (4.4 %), Bacteroidetes (1.7 %), Cyanobacteria/Chloroplast (1.5 %), TM7 (0.8 %), Gemmatimonadetes (0.2 %), and Nitrospirae (0.1 %) were present in SBR1. Proteobacteria (94.2 %), Bacteroidetes (2.9 %), Firmicutes (1.9 %), and Actinobacteria (0.7 %) were present in SBR2. Our results indicated the SBR1 fermentation system was more stable than that of SBR2 for PHB accumulation.

Population dynamics in controlled unsteady-state systems: An application to the degradation of glyphosate in a sequencing batch reactor

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

Devarakonda, M.S.

1988-01-01

Control over population dynamics and organism selection in a biological waste treatment system provides an effective means of engineering process efficiency. Examples of applications of organism selection include control of filamentous organisms, biological nutrient removal, industrial waste treatment requiring the removal of specific substrates, and hazardous waste treatment. Inherently, full scale biological waste treatment systems are unsteady state systems due to the variations in the waste streams and mass flow rates of the substrates. Some systems, however, have the capacity to impose controlled selective pressures on the biological population by means of their operation. An example of such a systemmore » is the Sequencing Batch Reactor (SBR) which was the experimental system utilized in this research work. The concepts of organism selection were studied in detail for the biodegradation of a herbicide waste stream, with glyphosate as the target compound. The SBR provided a reactor configuration capable of exerting the necessary selective pressures to select and enrich for a glyphosate degrading population. Based on results for bench scale SBRs, a hypothesis was developed to explain population dynamics in glyphosate degrading systems.« less

Digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage.

PubMed

Ghasimi, Dara S M; Tao, Yu; de Kreuk, Merle; Abbas, Ben; Zandvoort, Marcel H; van Lier, Jules B

2015-12-15

This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was toilet paper, which is estimated to be 10-14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10-25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Long-term exposure of bacterial and protozoan communities to TiO2 nanoparticles in an aerobic-sequencing batch reactor

NASA Astrophysics Data System (ADS)

Supha, Chitpisud; Boonto, Yuphada; Jindakaraked, Manee; Ananpattarachai, Jirapat; Kajitvichyanukul, Puangrat

2015-06-01

Titanium dioxide (TiO2) nanopowders at different concentrations (0-50 mg L-1) were injected into an aerobic-sequencing batch reactor (SBR) to investigate the effects of long-term exposure to nanoparticles on bacterial and protozoan communities. The detection of nanoparticles in the bioflocs was analyzed by scanning electron microscopy, transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The SBR wastewater experiments were conducted under the influence of ultraviolet light with photocatalytic TiO2. The intrusion of TiO2 nanoparticles was found both on the surface and inside of the bioflocs. The change of microbial population in terms of mixed liquor-suspended solids and the sludge volume index was monitored. The TiO2 nanoparticles tentatively exerted an adverse effect on the microbial population, causing the reduction of microorganisms (both bacteria and protozoa) in the SBR. The respiration inhibition rate of the bacteria was increased, and the viability of the microbial population was reduced at the high concentration (50 mg L-1) of TiO2. The decreasing number of protozoa in the presence of TiO2 nanoparticles during 20 days of treatment with 0.5 and 1.0 mg L-1 TiO2 is clearly demonstrated. The measured chemical oxygen demand (COD) in the effluent tends to increase with a long-term operation. The increase of COD in the system suggests a decrease in the efficiency of the wastewater treatment plant. However, the SBR can effectively remove the TiO2 nanoparticles (up to 50 mg L-1) from the effluent.

Transesterification of Waste Activated Sludge for Biosolids Reduction and Biodiesel Production.

PubMed

Maeng, Min Ho; Cha, Daniel K

2018-02-01

  Transesterification of waste activated sludge (WAS) was evaluated as a cost-effective technique to reduce excess biosolids and recover biodiesel feedstock from activated sludge treatment processes. A laboratory-scale sequencing batch reactor (SBR) was operated with recycling transesterification-treated WAS back to the aeration basin. Seventy percent recycling of WAS resulted in a 48% reduction of excess biosolids in comparison with a conventional SBR, which was operated in parallel as the control SBR. Biodiesel recovery of 8.0% (dried weight basis) was achieved at an optimum transesterification condition using acidic methanol and xylene as cosolvent. Average effluent soluble chemical oxygen demand (COD) and total suspended solids (TSS) concentrations from the test SBR and control SBR were comparable, indicating that the recycling of transesterification-treated WAS did not have detrimental effect on the effluent quality. This study demonstrated that transesterification and recycling of WAS may be a feasible technique for reducing excess biosolids, while producing valuable biodiesel feedstock from the activated sludge process.

Integrated ecotechnology approach towards treatment of complex wastewater with simultaneous bioenergy production.

PubMed

Hemalatha, Manupati; Sravan, J Shanthi; Yeruva, Dileep Kumar; Venkata Mohan, S

2017-10-01

Sequential integration of three stage diverse biological processes was studied by exploiting the individual process advantage towards enhanced treatment of complex chemical based wastewater. A successful attempt to integrate sequence batch reactor (SBR) with bioelectrochemical treatment (BET) and finally with microalgae treatment was studied. The sequential integration has showed individual substrate degradation (COD) of 55% in SBR, 49% in BET and 56% in microalgae, accounting for a consolidated treatment efficiency of 90%. Nitrates removal efficiency of 25% was observed in SBR, 31% in BET and 44% in microalgae, with a total efficiency of 72%. The SBR treated effluents fed to BET with the electrode intervention showed TDS removal. BET exhibited relatively higher process performance than SBR. The integration approach significantly overcame the individual process limitations along with value addition as biomass (1.75g/L), carbohydrates (640mg/g), lipids (15%) and bioelectricity. The study resulted in providing a strategy of combining SBR as pretreatment step to BET process and finally polishing with microalgae cultivation achieving the benefits of enhanced wastewater treatment along with value addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Treatability of cheese whey for single-cell protein production in nonsterile systems: Part II. The application of aerobic sequencing batch reactor (aerobic SBR) to produce high biomass of Dioszegia sp. TISTR 5792.

PubMed

Monkoondee, Sarawut; Kuntiya, Ampin; Chaiyaso, Thanongsak; Leksawasdi, Noppol; Techapun, Charin; Kawee-Ai, Arthitaya; Seesuriyachan, Phisit

2016-07-03

This study aimed to investigate the efficiency of an aerobic sequencing batch reactor (aerobic SBR) in a nonsterile system using the application of an experimental design via central composite design (CCD). The acidic whey obtained from lactic acid fermentation by immobilized Lactobacillus plantarum sp. TISTR 2265 was fed into the bioreactor of the aerobic SBR in an appropriate ratio between acidic whey and cheese whey to produce an acidic environment below 4.5 and then was used to support the growth of Dioszegia sp. TISTR 5792 by inhibiting bacterial contamination. At the optimal condition for a high yield of biomass production, the system was run with a hydraulic retention time (HRT) of 4 days, a solid retention time (SRT) of 8.22 days, and an acidic whey concentration of 80% feeding. The chemical oxygen demand (COD) decreased from 25,230 mg/L to 6,928 mg/L, which represented a COD removal of 72.15%. The yield of biomass production and lactose utilization by Dioszegia sp. TISTR 5792 were 13.14 g/L and 33.36%, respectively, with a long run of up to 180 cycles and the pH values of effluent were rose up to 8.32 without any pH adjustment.

Performance and microbial community dynamics of electricity-assisted sequencing batch reactor (SBR) for treatment of saline petrochemical wastewater.

PubMed

Liu, Jiaxin; Shi, Shengnan; Ji, Xiangyu; Jiang, Bei; Xue, Lanlan; Li, Meidi; Tan, Liang

2017-07-01

High-salinity wastewater is often difficult to treat by common biological technologies due to salinity stress on the bacterial community. Electricity-assisted anaerobic technologies have significantly enhanced the treatment performance by alleviating the impact of salinity stress on the bacterial community, but electricity-assisted aerobic technologies have less been reported. Herein, a novel bio-electrochemistry system has been designed and operated in which a pair of stainless iron mesh-graphite plate electrodes were installed into a sequencing batch reactor (SBR, designated as S1) to strengthen the performance of saline petrochemical wastewater under aerobic conditions. The removal efficiency of phenol and chemical oxygen demand (COD) in S1 were 94.1 and 91.2%, respectively, on day 45, which was clearly higher than the removal efficiency of a single SBR (S2) and an electrochemical reactor (S3), indicating that a coupling effect existed between the electrochemical process and biodegradation. A certain amount of salinity (≤8000 mg/L) could enhance the treatment performance in S1 but weaken that in S2. Illumina sequencing revealed that microbial communities in S1 on days 45 and 91 were richer and more diverse than in S2, which suggests that electrical stimulation could enhance the diversity and richness of the microbial community, and reduce the negative effect of salinity on the microorganisms and enrich some salt-adapted microorganisms, thus improve the ability of S1 to respond to salinity stress. This novel bio-electrochemistry system was shown to be an alternative technology for the high saline petrochemical wastewater.

Respirometric response and microbial succession of nitrifying sludge to m-cresol pulses in a sequencing batch reactor.

PubMed

Ordaz, Alberto; Sánchez, Mariana; Rivera, Rodrigo; Rojas, Rafael; Zepeda, Alejandro

2017-02-01

A nitrifying consortium was kinetically, stoichiometrically and molecularly characterized via the in situ pulse respirometric method and pyrosequencing analysis before and after the addition of m-cresol (25 mg C L -1 ) in a sequencing batch reactor (SBR). Five important kinetic and stoichiometric parameters were determined: the maximum oxygen uptake rate, the maximum nitrification rate, the oxidation yield, the biomass growth yield, and the substrate affinity constant. An inhibitory effect was observed in the nitrification process with a recovery of this by up to eight SBR cycles after m-cresol was added to the system. However, full recovery of the nitrification process was not observed, as the maximum oxygen uptake rate was 25% lower than that of the previous operation without m-cresol addition. Furthermore, the pyrosequencing analyses of the nitrifying consortium after the addition of only two pulses of 25 mg C L -1 m-cresol showed an important microbial community change represented by a decrease in the nitrifying populations and an increase in the populations degrading phenolic compounds.

Operation and model description of a sequencing batch reactor treating reject water for biological nitrogen removal via nitrite.

PubMed

Dosta, J; Galí, A; Benabdallah El-Hadj, T; Macé, S; Mata-Alvarez, J

2007-08-01

The aim of this study was the operation and model description of a sequencing batch reactor (SBR) for biological nitrogen removal (BNR) from a reject water (800-900 mg NH(4)(+)-NL(-1)) from a municipal wastewater treatment plant (WWTP). The SBR was operated with three cycles per day, temperature 30 degrees C, SRT 11 days and HRT 1 day. During the operational cycle, three alternating oxic/anoxic periods were performed to avoid alkalinity restrictions. Oxygen supply and working pH range were controlled to achieve the BNR via nitrite, which makes the process more economical. Under steady state conditions, a total nitrogen removal of 0.87 kg N (m(3)day)(-1) was reached. A four-step nitrogen removal model was developed to describe the process. This model enlarges the IWA activated sludge models for a more detailed description of the nitrogen elimination processes and their inhibitions. A closed intermittent-flow respirometer was set up for the estimation of the most relevant model parameters. Once calibrated, model predictions reproduced experimental data accurately.

Effect of cycle time on polyhydroxybutyrate (PHB) production in aerobic mixed cultures.

PubMed

Ozdemir, Sebnem; Akman, Dilek; Cirik, Kevser; Cinar, Ozer

2014-03-01

The aim of this study was to investigate the effect of cycle time on polyhydroxybutyrate (PHB) production under aerobic dynamic feeding system. The acetate-fed feast and famine sequencing batch reactor was used to enrich PHB accumulating microorganism. Sequencing batch reactor (SBR) was operated in four different cycle times (12, 8, 4, and 2 h) fed with a synthetic wastewater. The system performance was determined by monitoring total dissolved organic carbon, dissolved oxygen, oxidation-reduction potential, and PHB concentration. In this study, under steady-state conditions, the feast period of the SBR was found to allow the PHB storage while a certain part of stored PHB was used for continued growth in famine period. The percentage PHB storages by aerobic microorganism were at 16, 18, 42, and 55% for the 12, 8, 4, and 2-h cycle times, respectively. The PHB storage was increased as the length of the cycle time was decreased, and the ratio of the feast compared to the total cycle length was increased from around 13 to 33% for the 12 and 2-h cycle times, respectively.

Nitrate removal from high strength nitrate-bearing wastes in granular sludge sequencing batch reactors.

PubMed

Krishna Mohan, Tulasi Venkata; Renu, Kadali; Nancharaiah, Yarlagadda Venkata; Satya Sai, Pedapati Murali; Venugopalan, Vayalam Purath

2016-02-01

A 6-L sequencing batch reactor (SBR) was operated for development of granular sludge capable of denitrification of high strength nitrates. Complete and stable denitrification of up to 5420 mg L(-1) nitrate-N (2710 mg L(-1) nitrate-N in reactor) was achieved by feeding simulated nitrate waste at a C/N ratio of 3. Compact and dense denitrifying granular sludge with relatively stable microbial community was developed during reactor operation. Accumulation of large amounts of nitrite due to incomplete denitrification occurred when the SBR was fed with 5420 mg L(-1) NO3-N at a C/N ratio of 2. Complete denitrification could not be achieved at this C/N ratio, even after one week of reactor operation as the nitrite levels continued to accumulate. In order to improve denitrification performance, the reactor was fed with nitrate concentrations of 1354 mg L(-1), while keeping C/N ratio at 2. Subsequently, nitrate concentration in the feed was increased in a step-wise manner to establish complete denitrification of 5420 mg L(-1) NO3-N at a C/N ratio of 2. The results show that substrate concentration plays an important role in denitrification of high strength nitrate by influencing nitrite accumulation. Complete denitrification of high strength nitrates can be achieved at lower substrate concentrations, by an appropriate acclimatization strategy. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Anaerobic rumen SBR for degradation of cellulosic material.

PubMed

Barnes, S P; Keller, J

2004-01-01

Hydrolysis of organic particulates under anaerobic conditions is generally regarded as the rate limiting step in solid digestion processes. Rumen-based ecosystems appear to achieve very high hydrolysis rates for cellulosic organic material. This study aimed at the development and demonstration of an anaerobic sequencing batch reactor (SBR) process operating with a rumen-based microbial inoculum. Fibrous alpha cellulose was used as sole carbon substrate and the use of an SBR operating cycle allowed the utilisation of a high liquid flow rate (hydraulic retention time of 0.67 d) while maintaining a much longer solids retention time of 7 d. Complete mass balances for carbon and nitrogen, as well as COD balancing allowed the full characterisation of the process stoichiometry and kinetics. Elemental analysis of the biomass revealed a composition of C5H4.8O2.4N0.7, which is quite different from other generic biomass compositions used in the literature. The anaerobic rumen SBR was compared with another rumen-based reactor system in the literature which used a continuous filtration process for solid/liquid separation. This comparison showed that the volatile fatty acid production rate from cellulose in the anaerobic SBR was comparable with the performance achieved in the continuous system, although loading, substrate type and media composition were quite different between these two studies. Further evaluation of the anaerobic rumen SBR is required to determine its practical application for other substrates and to demonstrate the scale-up potential of this concept.

Effect of phenol on the nitrogen removal performance and microbial community structure and composition of an anammox reactor.

PubMed

Pereira, Alyne Duarte; Leal, Cíntia Dutra; Dias, Marcela França; Etchebehere, Claudia; Chernicharo, Carlos Augusto L; de Araújo, Juliana Calabria

2014-08-01

The effects of phenol on the nitrogen removal performance of a sequencing batch reactor (SBR) with anammox activity and on the microbial community within the reactor were evaluated. A phenol concentration of 300 mg L(-1) reduced the ammonium-nitrogen removal efficiency of the SBR from 96.5% to 47%. The addition of phenol changed the microbial community structure and composition considerably, as shown by denaturing gradient gel electrophoresis and 454 pyrosequencing of 16S rRNA genes. Some phyla, such as Proteobacteria, Verrucomicrobia, and Firmicutes, increased in abundance, whereas others, such as Acidobacteria, Chloroflexi, Planctomycetes, GN04, WS3, and NKB19, decreased. The diversity of the anammox bacteria was also affected by phenol: sequences related to Candidatus Brocadia fulgida were no longer detected, whereas sequences related to Ca. Brocadia sp. 40 and Ca. Jettenia asiatica persisted. These results indicate that phenol adversely affects anammox metabolism and changes the bacterial community within the anammox reactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cycle-time determination and process control of sequencing batch membrane bioreactors.

PubMed

Krampe, J

2013-01-01

In this paper a method to determine the cycle time for sequencing batch membrane bioreactors (SBMBRs) is introduced. One of the advantages of SBMBRs is the simplicity of adapting them to varying wastewater composition. The benefit of this flexibility can only be fully utilised if the cycle times are optimised for the specific inlet load conditions. This requires either proactive and ongoing operator adjustment or active predictive instrument-based control. Determination of the cycle times for conventional sequencing batch reactor (SBR) plants is usually based on experience. Due to the higher mixed liquor suspended solids concentrations in SBMBRs and the limited experience with their application, a new approach to calculate the cycle time had to be developed. Based on results from a semi-technical pilot plant, the paper presents an approach for calculating the cycle time in relation to the influent concentration according to the Activated Sludge Model No. 1 and the German HSG (Hochschulgruppe) Approach. The approach presented in this paper considers the increased solid contents in the reactor and the resultant shortened reaction times. This allows for an exact calculation of the nitrification and denitrification cycles with a tolerance of only a few minutes. Ultimately the same approach can be used for a predictive control strategy and for conventional SBR plants.

Comparing the performance and operation stability of an SBR and MBBR for single-stage nitritation-anammox treating wastewater with high organic load.

PubMed

Lackner, Susanne; Horn, Harald

2013-01-01

Single stage nitritation-anammox reactors have gained increasing attention for their application in municipal and industrial wastewater treatment. The most commonly used system in municipal reject water treatment is at present the sequencing batch reactor (SBR), the moving-bed biofilm reactor (MBBR) is the second most common. However, little is known about their applicability to industrial wastewaters with high C/N ratios. This study presents a comparative approach to evaluate the performance of these two systems by changing the influent from reject water (C:N ratio 1:1) stepwise to an industrial wastewater (C:N ratio 3:1). An intentionally induced temperature drop that led to nitrite accumulation was also tested. The results showed that the MBBR (1.9 kg-N m(-3) d(-1)) was superior to the SBR (0.5 kg-N m(-3) d(-1)) with at maximum up to four times higher volumetric nitrogen removal rates. Both systems accumulated nitrite (> 100 mg-N L(-1)) during the temperature drop from 30 degrees C to as low as 18 degrees C (MBBR) and 20 degrees C (SBR), which subsequently resulted in almost complete loss in the removal capacities. However, the previous removal rates could be re-established in both systems within approximately 40 days. In comparison, the MBBR showed the more stable and higher performance even though higher nitrite concentrations (up to 500 mg-N L(-1)) were encountered. Overall, MBBR operation and handling was also easier and the system was more robust to disturbances compared to the SBR.

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.

Assessment of bacterial and structural dynamics in aerobic granular biofilms

PubMed Central

Weissbrodt, David G.; Neu, Thomas R.; Kuhlicke, Ute; Rappaz, Yoan; Holliger, Christof

2013-01-01

Aerobic granular sludge (AGS) is based on self-granulated flocs forming mobile biofilms with a gel-like consistence. Bacterial and structural dynamics from flocs to granules were followed in anaerobic-aerobic sequencing batch reactors (SBR) fed with synthetic wastewater, namely a bubble column (BC-SBR) operated under wash-out conditions for fast granulation, and two stirred-tank enrichments of Accumulibacter (PAO-SBR) and Competibacter (GAO-SBR) operated at steady-state. In the BC-SBR, granules formed within 2 weeks by swelling of Zoogloea colonies around flocs, developing subsequently smooth zoogloeal biofilms. However, Zoogloea predominance (37–79%) led to deteriorated nutrient removal during the first months of reactor operation. Upon maturation, improved nitrification (80–100%), nitrogen removal (43–83%), and high but unstable dephosphatation (75–100%) were obtained. Proliferation of dense clusters of nitrifiers, Accumulibacter, and Competibacter from granule cores outwards resulted in heterogeneous bioaggregates, inside which only low abundance Zoogloea (<5%) were detected in biofilm interstices. The presence of different extracellular glycoconjugates detected by fluorescence lectin-binding analysis showed the complex nature of the intracellular matrix of these granules. In the PAO-SBR, granulation occurred within two months with abundant and active Accumulibacter populations (56 ± 10%) that were selected under full anaerobic uptake of volatile fatty acids and that aggregated as dense clusters within heterogeneous granules. Flocs self-granulated in the GAO-SBR after 480 days during a period of over-aeration caused by biofilm growth on the oxygen sensor. Granules were dominated by heterogeneous clusters of Competibacter (37 ± 11%). Zoogloea were never abundant in biomass of both PAO- and GAO-SBRs. This study showed that Zoogloea, Accumulibacter, and Competibacter affiliates can form granules, and that the granulation mechanisms rely on the dominant population involved. PMID:23847600

Enhanced biological phosphorus removal in a sequencing batch reactor using propionate as the sole carbon source.

PubMed

Pijuan, M; Saunders, A M; Guisasola, A; Baeza, J A; Casas, C; Blackall, L L

2004-01-05

An enhanced biological phosphorus removal (EBPR) system was developed in a sequencing batch reactor (SBR) using propionate as the sole carbon source. The microbial community was followed using fluorescence in situ hybridization (FISH) techniques and Candidatus 'Accumulibacter phosphatis' were quantified from the start up of the reactor until steady state. A series of SBR cycle studies was performed when 55% of the SBR biomass was Accumulibacter, a confirmed polyphosphate accumulating organism (PAO) and when Candidatus 'Competibacter phosphatis', a confirmed glycogen-accumulating organism (GAO), was essentially undetectable. These experiments evaluated two different carbon sources (propionate and acetate), and in every case, two different P-release rates were detected. The highest rate took place while there was volatile fatty acid (VFA) in the mixed liquor, and after the VFA was depleted a second P-release rate was observed. This second rate was very similar to the one detected in experiments performed without added VFA.A kinetic and stoichiometric model developed as a modification of Activated Sludge Model 2 (ASM2) including glycogen economy, was fitted to the experimental profiles. The validation and calibration of this model was carried out with the cycle study experiments performed using both VFAs. The effect of pH from 6.5 to 8.0 on anaerobic P-release and VFA-uptake and aerobic P-uptake was also studied using propionate. The optimal overall working pH was around 7.5. This is the first study of the microbial community involved in EBPR developed with propionate as a sole carbon source along with detailed process performance investigations of the propionate-utilizing PAOs. Copyright 2003 Wiley Periodicals, Inc.

Stoichiometric evaluation of partial nitritation, anammox and denitrification processes in a sequencing batch reactor and interpretation of online monitoring parameters.

PubMed

Langone, Michela; Ferrentino, Roberta; Cadonna, Maria; Andreottola, Gianni

2016-12-01

A laboratory-scale sequencing batch reactor (SBR) performing partial nitritation - anammox and denitrification was used to treat anaerobic digester effluents. The SBR cycle consisted of a short mixing filling phase followed by oxic and anoxic reaction phases. Working at 25 °C, an ammonium conversion efficiency of 96.5%, a total nitrogen removal efficiency of 88.6%, and an organic carbon removal efficiency of 63.5% were obtained at a nitrogen loading rate of 0.15 kg N m -3 d -1 , and a biodegradable organic carbon to nitrogen ratio of 0.37. The potential contribution of each biological process was evaluated by using a stoichiometric model. The nitritation contribution decreased as the temperature decreased, while the contribution from anammox depended on the wastewater type and soluble carbon to nitrogen ratio. Denitrification improved the total nitrogen removal efficiency, and it was influenced by the biodegradable organic carbon to nitrogen ratio. The characteristic patterns of conductivity, oxidation-reduction potential (ORP) and pH in the SBR cycle were well related to biological processes. Conductivity profiles were found to be directly related to the decreasing profiles of ammonium. Positive ORP values at the end of the anoxic phases were detected for total nitrogen removal efficiency of lower than 85%, and the occurrence of bending points on the ORP curves during the anoxic phases was associated with nitrite depletion by the anammox process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of Medium-Chain-Length Polyhydroxyalkanoate-Producing Bacteria in Activated Sludge Samples Enriched by Aerobic Periodic Feeding.

PubMed

Lee, Sun Hee; Kim, Jae Hee; Chung, Chung-Wook; Kim, Do Young; Rhee, Young Ha

2018-04-01

Analysis of mixed microbial populations responsible for the production of medium-chain-length polyhydroxyalkanoates (MCL-PHAs) under periodic substrate feeding in a sequencing batch reactor (SBR) was conducted. Regardless of activated sludge samples and the different MCL alkanoic acids used as the sole external carbon substrate, denaturing gradient gel electrophoresis analysis indicated that Pseudomonas aeruginosa was the dominant bacterium enriched during the SBR process. Several P. aeruginosa strains were isolated from the enriched activated sludge samples. The isolates were subdivided into two groups, one that produced only MCL-PHAs and another that produced both MCL- and short-chain-length PHAs. The SBR periodic feeding experiments with five representative MCL-PHA-producing Pseudomonas species revealed that P. aeruginosa has an advantage over other species that enables it to become dominant in the bacterial community.

Effect of SBR feeding strategy and feed composition on the stability of aerobic granular sludge in the treatment of a simulated textile wastewater.

PubMed

Franca, R D G; Ortigueira, J; Pinheiro, H M; Lourenço, N D

2017-09-01

Treatment of the highly polluting and variable textile industry wastewater using aerobic granular sludge (AGS) sequencing batch reactors (SBRs) has been recently suggested. Aiming to develop this technology application, two feeding strategies were compared regarding the capacity of anaerobic-aerobic SBRs to deal with disturbances in the composition of the simulated textile wastewater feed. Both a statically fed, anaerobic-aerobic SBR and an anaerobic plug-flow fed, anaerobic-aerobic SBR could cope with shocks of high azo dye concentration and organic load, the overall chemical oxygen demand and color removal yields being rapidly restored to 80%. Yet, subsequent azo dye metabolite bioconversion was not observed, along the 315-day run. Moreover, switching from a starch-based substrate to acetate in the feed composition deteriorated AGS stability. Overall, the plug-flow fed SBR recovered more rapidly from the imposed disturbances. Further research is needed towards guaranteeing long-term AGS stability during the treatment of textile wastewater.

SBR treatment of tank truck cleaning wastewater: sludge characteristics, chemical and ecotoxicological effluent quality.

PubMed

Caluwé, Michel; Dobbeleers, Thomas; Daens, Dominique; Geuens, Luc; Blust, Ronny; Dries, Jan

2017-08-02

A lab-scale activated sludge sequencing batch reactor (SBR) was used to treat tank truck cleaning (TTC) wastewater with different operational strategies (identified as different stages). The first stage was an adaptation period for the seed sludge that originated from a continuous fed industrial plant treating TTC wastewater. The first stage was followed by a dynamic reactor operation based on the oxygen uptake rate (OUR). Thirdly, dynamic SBR control based on OUR treated a daily changing influent. Lastly, the reactor was operated with a gradually shortened fixed cycle. During operation, sludge settling evolved from nearly no settling to good settling sludge in 16 days. The sludge volume index improved from 200 to 70 mL gMLSS -1 in 16 days and remained stable during the whole reactor operation. The average soluble chemical oxygen demand (sCOD) removal varied from 87.0% to 91.3% in the different stages while significant differences in the food to mass ratio were observed, varying from 0.11 (stage I) to 0.37 kgCOD.(kgMLVSS day) -1 (stage III). Effluent toxicity measurements were performed with Aliivibrio fischeri, Daphnia magna and Pseudokirchneriella subcapitata. Low sensitivity of Aliivibrio was observed. A few samples were acutely toxic for Daphnia; 50% of the tested effluent samples showed an inhibition of 100% for Pseudokirchneriella.

A new recycling technique for the waste tires reuse.

PubMed

Derakhshan, Zahra; Ghaneian, Mohammad Taghi; Mahvi, Amir Hossein; Oliveri Conti, Gea; Faramarzian, Mohammad; Dehghani, Mansooreh; Ferrante, Margherita

2017-10-01

In this series of laboratory experiments, the feasibility of using fixed bed biofilm carriers (FBBC) manufactured from existing reclaimed waste tires (RWTs) for wastewater treatment was evaluated. To assess polyamide yarn waste tires as a media, the fixed bed sequence batch reactor (FBSBR) was evaluated under different organic loading rate (OLRs). An experimental model was used to study the kinetics of substrate consumption in biofilm. Removal efficiency of soluble chemical oxygen demand (SCOD) ranged by 76-98% for the FBSBR compared to 71-96% in a sequencing batch reactor (SBR). Removal efficiency of FBBC was significantly increased by inoculating these RWTs carriers. The results revealed that the sludge production yield (Y obs ) was significantly less in the FBSBR compared to the SBR (p < 0.01). It also produced less sludge and recorded a lower stabilization ratio (VSS/TSS). The findings show that the Stover-Kincannon model was the best fit (R 2 > 99%) in a FBSBR. Results from this study suggest that RWTs to support biological activity for a variety of wastewater treatment applications as a biofilm carrier have high potential that better performance as COD and TSS removal and sludge settling properties and effluent quality supported these findings. Copyright © 2017. Published by Elsevier Inc.

Effect of magnesium oxide nanoparticles on microbial diversity and removal performance of sequencing batch reactor.

PubMed

Ma, Bingrui; Yu, Naling; Han, Yuetong; Gao, Mengchun; Wang, Sen; Li, Shanshan; Guo, Liang; She, Zonglian; Zhao, Yangguo; Jin, Chunji; Gao, Feng

2018-06-13

The performance, microbial enzymatic activity and microbial community of a sequencing batch reactor (SBR) have been explored under magnesium oxide nanoparticles (MgO NPs) stress. The NH 4 + -N removal efficiency kept relatively stable during the whole operational process. The MgO NPs at 30-60 mg/L slightly restrained the removal of chemical oxygen demand (COD), and the presence of MgO NPs also affected the denitrification and phosphorus removal. The specific oxygen uptake rate, nitrifying and denitrifying rates, phosphorus removal rate, and microbial enzymatic activities distinctly varied with the increase of MgO NPs concentration. The appearance of MgO NPs promoted more reactive oxygen species generation and lactate dehydrogenase leakage from activated sludge, suggesting that MgO NPs had obvious toxicity to activated sludge in the SBR. The protein and polysaccharide contents of extracellular polymeric substances from activated sludge increased with the increase of MgO NPs concentration. The microbial richness and diversity at different MgO NPs concentrations obviously varied at the phylum, class and genus levels due to the biological toxicity of MgO NPs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Treatment of Slaughter House Wastewater in a Sequencing Batch Reactor: Performance Evaluation and Biodegradation Kinetics

PubMed Central

Kundu, Pradyut; Debsarkar, Anupam; Mukherjee, Somnath

2013-01-01

Slaughterhouse wastewater contains diluted blood, protein, fat, and suspended solids, as a result the organic and nutrient concentration in this wastewater is vary high and the residues are partially solubilized, leading to a highly contaminating effect in riverbeds and other water bodies if the same is let off untreated. The performance of a laboratory-scale Sequencing Batch Reactor (SBR) has been investigated in aerobic-anoxic sequential mode for simultaneous removal of organic carbon and nitrogen from slaughterhouse wastewater. The reactor was operated under three different variations of aerobic-anoxic sequence, namely, (4+4), (5+3), and (3+5) hr. of total react period with two different sets of influent soluble COD (SCOD) and ammonia nitrogen (NH4 +-N) level 1000 ± 50 mg/L, and 90 ± 10 mg/L, 1000 ± 50 mg/L and 180 ± 10 mg/L, respectively. It was observed that from 86 to 95% of SCOD removal is accomplished at the end of 8.0 hr of total react period. In case of (4+4) aerobic-anoxic operating cycle, a reasonable degree of nitrification 90.12 and 74.75% corresponding to initial NH4 +-N value of 96.58 and 176.85 mg/L, respectively, were achieved. The biokinetic coefficients (k, K s, Y, k d) were also determined for performance evaluation of SBR for scaling full-scale reactor in future operation. PMID:24027751

Contamination level of four priority phthalates in North Indian wastewater treatment plants and their fate in sequencing batch reactor systems.

PubMed

Gani, Khalid Muzamil; Rajpal, Ankur; Kazmi, Absar Ahmad

2016-03-01

The contamination level of four phthalates in untreated and treated wastewater of fifteen wastewater treatment plants (WWTPs) and their fate in a full scale sequencing batch reactor (SBR) based WWTP was evaluated in this study. The four phthalates were diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP) and diethylhexyl phthalate (DEHP). All compounds were present in untreated wastewater with DEHP being present in the highest mean concentration of 28.4 ± 5.3 μg L(-1). The concentration was in the range of 7.3 μg L(-1) (BBP) to 28.4 μg L(-1) (DEHP) in untreated wastewater and 1.3 μg L(-1) (DBP) to 2.6 μg L(-1) (DEHP) in treated wastewater. The nutrient removal process and advance tertiary treatment based WWTPs showed the highest phthalate removal efficiencies of 87% and 93%, respectively. The correlation between phthalate removal and conventional performance of WWTPs was positive. Fate analysis of these phthalates in a SBR based WWTP showed that total removal of the sum of phthalates in a primary settling tank and SBR was 84% out of which 55% is removed by biodegradation and 29% was removed by sorption to primary and secondary sludge. The percentage removal of four phthalates in primary settling tanks was 18%. Comparison of the diluted effluent DEHP concentration with its environmental quality standards showed that the dilution in an effluent receiving water body can reduce the DEHP emissions to acceptable values.

Long-term dynamic and pseudo-state modeling of complete partial nitrification process at high nitrogen loading rates in a sequential batch reactor (SBR).

PubMed

Soliman, Moomen; Eldyasti, Ahmed

2017-06-01

Recently, partial nitrification has been adopted widely either for the nitrite shunt process or intermediate nitrite generation step for the Anammox process. However, partial nitrification has been hindered by the complexity of maintaining stable nitrite accumulation at high nitrogen loading rates (NLR) which affect the feasibility of the process for high nitrogen content wastewater. Thus, the operational data of a lab scale SBR performing complete partial nitrification as a first step of nitrite shunt process at NLRs of 0.3-1.2kg/(m 3 d) have been used to calibrate and validate a process model developed using BioWin® in order to describe the long-term dynamic behavior of the SBR. Moreover, an identifiability analysis step has been introduced to the calibration protocol to eliminate the needs of the respirometric analysis for SBR models. The calibrated model was able to predict accurately the daily effluent ammonia, nitrate, nitrite, alkalinity concentrations and pH during all different operational conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electro-peroxone pretreatment for enhanced simulated hospital wastewater treatment and antibiotic resistance genes reduction.

PubMed

Zheng, He-Shan; Guo, Wan-Qian; Wu, Qu-Li; Ren, Nan-Qi; Chang, Jo-Shu

2018-06-01

Hospital wastewater is one of the possible sources responsible for antibiotic resistant bacteria spread into the environment. This study proposed a promising strategy, electro-peroxone (E-peroxone) pretreatment followed by a sequencing batch reactor (SBR) for simulated hospital wastewater treatment, aiming to enhance the wastewater treatment performance and to reduce antibiotic resistance genes production simultaneously. The highest chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiency of 94.3% and 92.8% were obtained using the E-peroxone-SBR process. The microbial community analysis through high-throughput sequencing showed that E-peroxone pretreatment could guarantee microbial richness and diversity in SBR, as well as reduce the microbial inhibitions caused by antibiotic and raise the amount of nitrification and denitrification genera. Specially, quantitative real-time PCRs revealed that E-peroxone pretreatment could largely reduce the numbers and contents of antibiotic resistance genes (ARGs) production in the following biological treatment unit. It was indicated that E-peroxone-SBR process may provide an effective way for hospital wastewater treatment and possible ARGs reduction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Plasmid-mediated bioaugmentation of sequencing batch reactors for enhancement of 2,4-dichlorophenoxyacetic acid removal in wastewater using plasmid pJP4.

PubMed

Tsutsui, Hirofumi; Anami, Yasutaka; Matsuda, Masami; Hashimoto, Kurumi; Inoue, Daisuke; Sei, Kazunari; Soda, Satoshi; Ike, Michihiko

2013-06-01

Plasmid-mediated bioaugmentation was demonstrated using sequencing batch reactors (SBRs) for enhancing 2,4-dichlorophenoxyacetic acid (2,4-D) removal by introducing Cupriavidus necator JMP134 and Escherichia coli HB101 harboring 2,4-D-degrading plasmid pJP4. C. necator JMP134(pJP4) can mineralize and grow on 2,4-D, while E. coli HB101(pJP4) cannot assimilate 2,4-D because it lacks the chromosomal genes to degrade the intermediates. The SBR with C. necator JMP134(pJP4) showed 100 % removal against 200 mg/l of 2,4-D just after its introduction, after which 2,4-D removal dropped to 0 % on day 7 with the decline in viability of the introduced strain. The SBR with E. coli HB101(pJP4) showed low 2,4-D removal, i.e., below 10 %, until day 7. Transconjugant strains of Pseudomonas and Achromobacter isolated on day 7 could not grow on 2,4-D. Both SBRs started removing 2,4-D at 100 % after day 16 with the appearance of 2,4-D-degrading transconjugants belonging to Achromobacter, Burkholderia, Cupriavidus, and Pandoraea. After the influent 2,4-D concentration was increased to 500 mg/l on day 65, the SBR with E. coli HB101(pJP4) maintained stable 2,4-D removal of more than 95 %. Although the SBR with C. necator JMP134(pJP4) showed a temporal depression of 2,4-D removal of 65 % on day 76, almost 100 % removal was achieved thereafter. During this period, transconjugants isolated from both SBRs were mainly Achromobacter with high 2,4-D-degrading capability. In conclusion, plasmid-mediated bioaugmentation can enhance the degradation capability of activated sludge regardless of the survival of introduced strains and their 2,4-D degradation capacity.

Microalgal bacterial flocs treating paper mill effluent: A sunlight-based approach for removing carbon, nitrogen, phosphorus, and calcium.

PubMed

Van Den Hende, Sofie; Rodrigues, André; Hamaekers, Helen; Sonnenholzner, Stanislaus; Vervaeren, Han; Boon, Nico

2017-10-25

Treatment of upflow anaerobic sludge blanket (UASB) effluent from a paper mill in aerated activated sludge reactors involves high aeration costs. Moreover, this calcium-rich effluent leads to problematic scale formation. Therefore, a novel strategy for the aerobic treatment of paper mill UASB effluent in microalgal bacterial floc sequencing batch reactors (MaB-floc SBRs) is proposed, in which oxygen is provided via photosynthesis, and calcium is removed via bio-mineralization. Based on the results of batch experiments in the course of this study, a MaB-floc SBR was operated at an initial neutral pH. This SBR removed 58±21% organic carbon, 27±8% inorganic carbon, 77±5% nitrogen, 73±2% phosphorus, and 27±11% calcium. MaB-flocs contained 10±3% calcium, including biologically-influenced calcite crystals. The removal of calcium and inorganic carbon by MaB-flocs significantly decreased when inhibiting extracellular carbonic anhydrase (CA), an enzyme that catalyses the hydration and dehydration of CO 2 . This study demonstrates the potential of MaB-floc SBRs for the alternative treatment of calcium-rich paper mill effluent, and highlights the importance of extracellular CA in this treatment process. Copyright © 2017 Elsevier B.V. All rights reserved.

Sludge granulation and performance of a low superficial gas velocity sequencing batch reactor (SBR) in the treatment of prepared sanitary wastewater.

PubMed

Ji, Guodong; Zhai, Fengmin; Wang, Rongjing; Ni, Jinren

2010-12-01

A sequencing batch reactor (SBR) employing a low superficial gas velocity was used to produce aerobic granular sludge for wastewater treatment. At a gas velocity of 0.0056 m s(-1) sludge containing a mixture of light yellow and black granules with similar functional groups was quickly formed. The black granules contained crystals of CaCO(3), FeS, and Fe(2)O(3) as well as filamentous bacteria that strengthened the particles and reduced the mass transfer resistance. No inorganic crystals were detected in the yellow sludge granules, and their structure was maintained through cohesion mediated by extracellular polymeric substances (EPS). The light yellow granules were denser and offered better settling performance than the black granules, enhancing the settling properties of the mixed sludge. During a 12-h cycle, the maximum reductions in chemical oxygen demand (COD), NH(3)-N, and total nitrogen (TN) occurred at 240, 480, and 360 min with removal efficiencies of 90%, 90%, and 54%. When the cycle time was limited to 480 min, self-dissolution of the granules was avoided while sill maintaining removal efficiencies for COD, NH(3)-N, and TN of 88%, 90%, and 53%. 2010 Elsevier Ltd. All rights reserved.

Enhancing the performance of sequencing batch reactors by adding crushed date seeds to remove high concentrations of 2,4-dinitrophenol.

PubMed

Al-Mutairi, Nayef Z

2011-11-01

Wastewater treatment systems using simultaneous adsorption and biodegradation processes have been successful in treating toxic pollutants present in industrial wastewater. The goal of this investigation was to assess the effectiveness of date seeds in reducing the toxic effects of 2,4-dinitrophenol (DNP) on activated sludge microorganisms. Two identical sequencing batch reactors (SBRs) (4-L glass vessel), each with a 3.5-L working volume, were used. The initial DNP concentrations in the reactor were 50, 75, 100, 250, and 500 mg/L. The reactor amended with date seeds was capable of degrading DNP at significantly greater rates (11 +/- 2.5 mg/L x h) than the control SBR (4 +/- 1.2 mg/L x h) at a 95% confidence level. Date seeds can be added to the mixed liquor of activated sludge treatment plants to remove high concentrations of DNP from wastewater, to protect the treatment plant against toxic components in the influent and enhance the settling characteristics of the mixed liquor.

Shortcut nitrification-denitrification by means of autochthonous halophilic biomass in an SBR treating fish-canning wastewater.

PubMed

Capodici, Marco; Corsino, Santo Fabio; Torregrossa, Michele; Viviani, Gaspare

2018-02-15

Autochthonous halophilic biomass was cultivated in a sequencing batch reactor (SBR) aimed at analyzing the potential use of autochthonous halophilic activated sludge in treating saline industrial wastewater. Despite the high salt concentration (30 g NaCl L -1 ), biological oxygen demand (BOD) and total suspended solids (TSS), removal efficiencies were higher than 90%. More than 95% of the nitrogen was removed via a shortcut nitrification-denitrification process. Both the autotrophic and heterotrophic biomass samples exhibited high biological activity. The use of autochthonous halophilic biomass led to high-quality effluent and helped to manage the issues related to nitrogen removal in saline wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characteristics and performance of aerobic granular sludge treating rubber wastewater at different hydraulic retention time.

PubMed

Rosman, Noor Hasyimah; Nor Anuar, Aznah; Chelliapan, Shreeshivadasan; Md Din, Mohd Fadhil; Ujang, Zaini

2014-06-01

The influence of hydraulic retention time (HRT, 24, 12, and 6h) on the physical characteristics of granules and performance of a sequencing batch reactor (SBR) treating rubber wastewater was investigated. Results showed larger granular sludge formation at HRT of 6h with a mean size of 2.0±0.1mm, sludge volume index of 20.1mLg(-1), settling velocity of 61mh(-1), density of 78.2gL(-1) and integrity coefficient of 9.54. Scanning electron microscope analyses revealed different morphology of microorganisms and structural features of granules when operated at various HRT. The results also demonstrated that up to 98.4% COD reduction was achieved when the reactor was operated at low HRT (6h). Around 92.7% and 89.5% removal efficiency was noted for ammonia and total nitrogen in the granular SBR system during the treatment of rubber wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sludge reduction by uncoupling metabolism: SBR tests with para-nitrophenol and a commercial uncoupler.

PubMed

Zuriaga-Agustí, E; Mendoza-Roca, J A; Bes-Piá, A; Alonso-Molina, J L; Amorós-Muñoz, I

2016-11-01

Nowadays cost reduction is a very important issue in wastewater treatment plants. One way, is to minimize the sludge production. Microorganisms break down the organic matter into inorganic compounds through catabolism. Uncoupling metabolism is a method which promote catabolism reactions instead of anabolism ones, where adenosine triphosphate synthesis is inhibited. In this work, the influence of the addition of para-nitrophenol and a commercial reagent to a sequencing batch reactor (SBR) on sludge production and process performance has been analyzed. Three laboratory SBRs were operated in parallel to compare the effect of the addition of both reagents with a control reactor. SBRs were fed with synthetic wastewater and were operated with the same conditions. Results showed that sludge production was slightly reduced for the tested para-nitrophenol concentrations (20 and 25 mg/L) and for a LODOred dose of 1 mL/day. Biological process performance was not influenced and high COD removals were achieved. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel approach to enhance biological nutrient removal using a culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (Rpf) in SBR process.

PubMed

Liu, Yindong; Su, Xiaomei; Lu, Lian; Ding, Linxian; Shen, Chaofeng

2016-03-01

A culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (SRpf) was used to enhance the biological nutrient removal of potentially functional bacteria. The obtained results suggest that SRpf accelerated the start-up process and significantly enhanced the biological nutrient removal in sequencing batch reactor (SBR). PO4 (3-)-P removal efficiency increased by over 12 % and total nitrogen removal efficiency increased by over 8 % in treatment reactor acclimated by SRpf compared with those without SRpf addition. The Illumina high-throughput sequencing analysis showed that SRpf played an essential role in shifts in the composition and diversity of bacterial community. The phyla of Proteobacteria and Actinobacteria, which were closely related to biological nutrient removal, were greatly abundant after SRpf addition. This study demonstrates that SRpf acclimation or addition might hold great potential as an efficient and cost-effective alternative for wastewater treatment plants (WWTPs) to meet more stringent operation conditions and legislations.

Advanced treatment of sodium dithionite wastewater using the combination of coagulation, catalytic ozonation, and SBR.

PubMed

Zou, Xiao-Ling

2017-10-01

A combined process of coagulation-catalytic ozonation-anaerobic sequencing batch reactor (ASBR)-SBR was developed at lab scale for treating a real sodium dithionite wastewater with an initial chemical oxygen demand (COD) of 21,760-22,450 mg/L. Catalytic ozonation with the prepared cerium oxide (CeO 2 )/granular activated carbon catalyst significantly enhances wastewater biodegradability and reduces wastewater microtoxicity. The results show that, under the optimum conditions, the removal efficiencies of COD and suspended solids are averagely 99.3% and 95.6%, respectively, and the quality of final effluent can meet the national discharge standard of China. The coagulation and ASBR processes remove a considerable proportion of organic matter, while the SBR plays an important role in post-polish of final effluent. The ecotoxicity of the wastewater is greatly reduced after undergoing the hybrid treatment. This work demonstrates that the hybrid system has the potential to be applied for the advanced treatment of high-strength industrial wastewater.

Genotoxicity evaluation of effluents from textile industries of the region Fez-Boulmane, Morocco: a case study.

PubMed

Giorgetti, Lucia; Talouizte, Hakima; Merzouki, Mohammed; Caltavuturo, Leonardo; Geri, Chiara; Frassinetti, Stefania

2011-11-01

In order to investigate the biological hazard of effluents from textile industries of Fez-Boulmane region in Morocco, mutagenicity and phytotoxicity tests were performed on different biological systems. Moreover, the efficiency of a Sequencing Batch Reactor (SBR) system, working by activated sludge on a laboratory scale, was estimated by comparing the ecotoxicity results observed before and after wastewater treatment. Evaluation of the genotoxic potential was investigated by means of classic mutagenicity tests on D7 strain of Saccharomyces cerevisiae and by phytotoxicity tests on Allium sativum L., Vicia faba L. and Lactuca sativa L., estimating micronuclei presence, mitotic index and cytogenetic anomalies. The results obtained by testing untreated wastewater demonstrated major genotoxicity effects in S. cerevisiae and various levels of phytotoxicity in the three plant systems, while after SBR treatment no more ecotoxicological consequences were observed. These data confirm the effectiveness of the SBR system in removing toxic substances from textile wastewaters in Fez-Boulmane region. Copyright © 2011 Elsevier Inc. All rights reserved.

Link between microbial composition and carbon substrate-uptake preferences in a PHA-storing community

PubMed Central

Albuquerque, Maria G E; Carvalho, Gilda; Kragelund, Caroline; Silva, Ana F; Barreto Crespo, Maria T; Reis, Maria A M; Nielsen, Per H

2013-01-01

The microbial community of a fermented molasses-fed sequencing batch reactor (SBR) operated under feast and famine conditions for production of polyhydroxyalkanoates (PHAs) was identified and quantified through a 16 S rRNA gene clone library and fluorescence in situ hybridization (FISH). The microbial enrichment was found to be composed of PHA-storing populations (84% of the microbial community), comprising members of the genera Azoarcus, Thauera and Paracoccus. The dominant PHA-storing populations ensured the high functional stability of the system (characterized by high PHA-storage efficiency, up to 60% PHA content). The fermented molasses contained primarily acetate, propionate, butyrate and valerate. The substrate preferences were determined by microautoradiography-FISH and differences in the substrate-uptake capabilities for the various probe-defined populations were found. The results showed that in the presence of multiple substrates, microbial populations specialized in different substrates were selected, thereby co-existing in the SBR by adapting to different niches. Azoarcus and Thauera, primarily consumed acetate and butyrate, respectively. Paracoccus consumed a broader range of substrates and had a higher cell-specific substrate uptake. The relative species composition and their substrate specialization were reflected in the substrate removal rates of different volatile fatty acids in the SBR reactor. PMID:22810062

Recovery of phosphorus and volatile fatty acids from wastewater and food waste with an iron-flocculation sequencing batch reactor and acidogenic co-fermentation.

PubMed

Li, Ruo-Hong; Li, Xiao-Yan

2017-12-01

A sequencing batch reactor-based system was developed for enhanced phosphorus (P) removal and recovery from municipal wastewater. The system consists of an iron-dosing SBR for P precipitation and a side-stream anaerobic reactor for sludge co-fermentation with food waste. During co-fermentation, sludge and food waste undergo acidogenesis, releasing phosphates under acidic conditions and producing volatile fatty acids (VFAs) into the supernatant. A few types of typical food waste were investigated for their effectiveness in acidogenesis and related enzymatic activities. The results show that approximately 96.4% of total P in wastewater was retained in activated sludge. Food waste with a high starch content favoured acidogenic fermentation. Around 55.7% of P from wastewater was recovered as vivianite, and around 66% of food waste loading was converted into VFAs. The new integration formed an effective system for wastewater treatment, food waste processing and simultaneous recovery of P and VFAs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reduction of excess sludge in a sequencing batch reactor by lysis-cryptic growth using quick lime for disintegration under low temperature.

PubMed

Lv, Xiao-Mei; Song, Ju-Sheng; Li, Ji; Zhai, Kun

2017-08-01

In the present study, quick-lime-based thermal-alkaline sludge disintegration (SD) under low temperature was combined with cryptic growth to investigate the excess sludge reduction efficiency in the sequencing batch reactor (SBR). The optimized condition of SD was as follows: T = 80℃, pH = 11, t = 180 min, and the SD rate was about 42.1%. With 65.6% of excess sludge disintegrated and returned to the SBR, the system achieved sludge reduction rate of about 40.1%. The lysis-cryptic growth still obtained satisfactory sludge reduction efficiency despite the comparative low SD rate, which suggested that disintegration rate might not be the decisive factor for cryptic-growth-based sludge reduction. Lysis-cryptic growth did not impact the effluent quality, yet the phosphorus removal performance was enhanced, with effluent total phosphorus concentration decreased by 0.3 mg/L (33%). Crystal compounds of calcium phosphate precipitate were detected in the system by Fourier transform infrared spectroscopy and X-ray diffraction, which indicated the phosphorus removal potential of SD using lime. Moreover, endogenous dehydrogenase activity of activated sludge in the lysis-cryptic system was enhanced, which was beneficial for sludge reduction. SD and cryptic growth in the present study demonstrates an economical and effective approach for sludge reduction.

Minimizing N2O emissions and carbon footprint on a full-scale activated sludge sequencing batch reactor.

PubMed

Rodriguez-Caballero, A; Aymerich, I; Marques, Ricardo; Poch, M; Pijuan, M

2015-03-15

A continuous, on-line quantification of the nitrous oxide (N2O) emissions from a full-scale sequencing batch reactor (SBR) placed in a municipal wastewater treatment plant (WWTP) was performed in this study. In general, N2O emissions from the biological wastewater treatment system were 97.1 ± 6.9 g N2O-N/Kg [Formula: see text] consumed or 6.8% of the influent [Formula: see text] load. In the WWTP of this study, N2O emissions accounted for over 60% of the total carbon footprint of the facility, on average. Different cycle configurations were implemented in the SBR aiming at reaching acceptable effluent values. Each cycle configuration consisted of sequences of aerated and non-aerated phases of different time length being controlled by the ammonium set-point fixed. Cycles with long aerated phases showed the largest N2O emissions, with the consequent increase in carbon footprint. Cycle configurations with intermittent aeration (aerated phases up to 20-30 min followed by short anoxic phases) were proven to effectively reduce N2O emissions, without compromising nitrification performance or increasing electricity consumption. This is the first study in which a successful operational strategy for N2O mitigation is identified at full-scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fe(II) oxidation during acid mine drainage neutralization in a pilot-scale Sequencing Batch Reactor.

PubMed

Zvimba, J N; Mathye, M; Vadapalli, V R K; Swanepoel, H; Bologo, L

2013-01-01

This study investigated Fe(II) oxidation during acid mine drainage (AMD) neutralization using CaCO3 in a pilot-scale Sequencing Batch Reactor (SBR) of hydraulic retention time (HRT) of 90 min and sludge retention time (SRT) of 360 min in the presence of air. The removal kinetics of Fe(II), of initial concentration 1,033 ± 0 mg/L, from AMD through oxidation to Fe(III) was observed to depend on both pH and suspended solids, resulting in Fe(II) levels of 679 ± 32, 242 ± 64, 46 ± 16 and 28 ± 0 mg/L recorded after cycles 1, 2, 3 and 4 respectively, with complete Fe(II) oxidation only achieved after complete neutralization of AMD. Generally, it takes 30 min to completely oxidize Fe(II) during cycle 4, suggesting that further optimization of SBR operation based on both pH and suspended solids manipulation can result in significant reduction of the number of cycles required to achieve acceptable Fe(II) oxidation for removal as ferric hydroxide. Overall, complete removal of Fe(II) during AMD neutralization is attractive as it promotes recovery of better quality waste gypsum, key to downstream gypsum beneficiation for recovery of valuables, thereby enabling some treatment-cost recovery and prevention of environmental pollution from dumping of sludge into landfills.

New insights into the transformation of trimethoprim during biological wastewater treatment.

PubMed

Jewell, Kevin S; Castronovo, Sandro; Wick, Arne; Falås, Per; Joss, Adriano; Ternes, Thomas A

2016-01-01

The antibiotic trimethoprim (TMP), a micropollutant found at μg/L levels in raw wastewater, was investigated with regard to its (bio)transformation during biological wastewater treatment. A pilot-scale, nitrifying/denitrifying Sequencing Batch Reactor (SBR) fed with municipal wastewater was monitored for TMP removal during a 16-month monitoring study. Laboratory-scaled bioreactors spiked with TMP were applied to identify the transformation products (TPs). In total, six TPs could be identified from TMP. However, the TP formation was influenced by the spike concentration. At an initial concentration of 500 μg/L TMP, only two TPs were found, whereas at 5 μg/L a completely different transformation pathway led to four further TPs. At low concentrations, TMP was demethylated forming 4-desmethyl-TMP, which was then quickly hydroxylated, oxidized and cleaved forming 2,4-diaminopyrimidine-5-carboxylic acid (DAPC) via two intermediate TPs. DAPC was detected in the SBR effluent in a 3-d composite sample with 61 ng/L, which accounts for 52% of the attenuated TMP. The primary degradation at low spiking levels was best modelled by a pseudo-first order kinetic. Considering the SBR, the model predicted a TMP removal of 88-94% for the reactor, consistent with a monitoring campaign exhibiting an average removal of >83%. Both the TP formation profiles and kinetic modelling indicated that only the results from the bioreactor tests at low spike concentrations were representative of the transformation in the SBR. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Grey water treatment at a sports centre for reuse in irrigation: a case study.

PubMed

Gabarró, J; Batchelli, L; Balaguer, M D; Puig, S; Colprim, J

2013-01-01

Grey water has long been considered a promising option for dealing with water scarcity and reuse. However, factors such as lack of macronutrients and low carbon content make its treatment challenging. The aim of this paper was to investigate the applicability of sequencing batch reactor (SBR) technology to on-site grey water treatment at a sports centre for reuse in irrigation. The results demonstrated that the regenerated water complied with microbiological parameters concerning restriction of solids and organic matter removal. Denitrification was not fully accomplished, but ammonium was totally oxidised and low concentrations of nitrates were achieved. Effluent with good appearance and no odour was used in an experimental study to irrigate a grid system containing natural and artificial grass sections. The conclusion is that SBR technology offers a promising treatment for grey water.

Carbon mass balance and microbial ecology in a laboratory scale reactor achieving simultaneous sludge reduction and nutrient removal.

PubMed

Huang, Pei; Li, Liang; Kotay, Shireen Meher; Goel, Ramesh

2014-04-15

Solids reduction in activated sludge processes (ASP) at source using process manipulation has been researched widely over the last two-decades. However, the absence of nutrient removal component, lack of understanding on the organic carbon, and limited information on key microbial community in solids minimizing ASP preclude the widespread acceptance of sludge minimizing processes. In this manuscript, we report simultaneous solids reduction through anaerobiosis along with nitrogen and phosphorus removals. The manuscript also reports carbon mass balance using stable isotope of carbon, microbial ecology of nitrifiers and polyphosphate accumulating organisms (PAOs). Two laboratory scale reactors were operated in anaerobic-aerobic-anoxic (A(2)O) mode. One reactor was run in the standard mode (hereafter called the control-SBR) simulating conventional A(2)O type of activated sludge process and the second reactor was run in the sludge minimizing mode (called the modified-SBR). Unlike other research efforts where the sludge minimizing reactor was maintained at nearly infinite solids retention time (SRT). To sustain the efficient nutrient removal, the modified-SBR in this research was operated at a very small solids yield rather than at infinite SRT. Both reactors showed consistent NH3-N, phosphorus and COD removals over a period of 263 days. Both reactors also showed active denitrification during the anoxic phase even if there was no organic carbon source available during this phase, suggesting the presence of denitrifying PAOs (DNPAOs). The observed solids yield in the modified-SBR was 60% less than the observed solids yield in the control-SBR. Specific oxygen uptake rate (SOUR) for the modified-SBR was almost 44% more than the control-SBR under identical feeding conditions, but was nearly the same for both reactors under fasting conditions. The modified-SBR showed greater diversity of ammonia oxidizing bacteria and PAOs compared to the control-SBR. The diversity of PAOs in the modified-SBR was even more interesting in which case novel clades of Candidatus Accumulibacter phosphatis (CAP), an uncultured but widely found PAOs, were found. Copyright © 2014 Elsevier Ltd. All rights reserved.

Community proteomics provides functional insight into polyhydroxyalkanoate production by a mixed microbial culture cultivated on fermented dairy manure.

PubMed

Hanson, Andrea J; Guho, Nicholas M; Paszczynski, Andrzej J; Coats, Erik R

2016-09-01

Polyhydroxyalkanoates (PHAs) are bio-based, biodegradable polyesters that can be produced from organic-rich waste streams using mixed microbial cultures (MMCs). To maximize PHA production, MMCs are enriched for bacteria with a high polymer storage capacity through the application of aerobic dynamic feeding (ADF) in a sequencing batch reactor (SBR), which consequently induces a feast-famine metabolic response. Though the feast-famine response is generally understood empirically at a macro-level, the molecular level is less refined. The objective of this study was to investigate the microbial community composition and proteome profile of an enriched MMC cultivated on fermented dairy manure. The enriched MMC exhibited a feast-famine response and was capable of producing up to 40 % (wt. basis) PHA in a fed-batch reactor. High-throughput 16S rRNA gene sequencing revealed a microbial community dominated by Meganema, a known PHA-producing genus not often observed in high abundance in enrichment SBRs. The application of the proteomic methods two-dimensional electrophoresis and LC-MS/MS revealed PHA synthesis, energy generation, and protein synthesis prominently occurring during the feast phase, corroborating bulk solution variable observations and theoretical expectations. During the famine phase, nutrient transport, acyl-CoA metabolism, additional energy generation, and housekeeping functions were more pronounced, informing previously under-determined MMC functionality under famine conditions. During fed-batch PHA production, acetyl-CoA acetyltransferase and PHA granule-bound phasin proteins were in increased abundance relative to the SBR, supporting the higher PHA content observed. Collectively, the results provide unique microbial community structural and functional insight into feast-famine PHA production from waste feedstocks using MMCs.

Rapid aerobic granulation in an SBR treating piggery wastewater by seeding sludge from a municipal WWTP.

PubMed

Liu, Jun; Li, Jun; Wang, Xiaodong; Zhang, Qi; Littleton, Helen

2017-01-01

Aerobic sludge granulation was rapidly obtained in the erlenmeyer bottle and sequencing batch reactor (SBR) using piggery wastewater. Aerobic granulation occurred on day 3 and granules with mean diameter of 0.2mm and SVI 30 of 20.3mL/g formed in SBR on day 18. High concentrations of Ca and Fe in the raw piggery wastewater and operating mode accelerated aerobic granulation, even though the seed sludge was from a municipal wastewater treatment plant (WWTP). Alpha diversity analysis revealed Operational Taxonomic Units, Shannon, ACE and Chao 1 indexes in aerobic granules were 2013, 5.51, 4665.5 and 3734.5, which were obviously lower compared to seed sludge. The percentages of major microbial communities, such as Proteobacteria, Bacteroidetes and Firmicutes were obviously higher in aerobic granules than seed sludge. Chloroflexi, Planctomycetes, Actinobacteria, TM7 and Acidobacteria showed much higher abundances in the inoculum. The main reasons might be the characteristics of raw piggery wastewater and granule structure. Copyright © 2016. Published by Elsevier B.V.

Methane production from acid hydrolysates of Agave tequilana bagasse: evaluation of hydrolysis conditions and methane yield.

PubMed

Arreola-Vargas, Jorge; Ojeda-Castillo, Valeria; Snell-Castro, Raúl; Corona-González, Rosa Isela; Alatriste-Mondragón, Felipe; Méndez-Acosta, Hugo O

2015-04-01

Evaluation of diluted acid hydrolysis for sugar extraction from cooked and uncooked Agave tequilana bagasse and feasibility of using the hydrolysates as substrate for methane production, with and without nutrient addition, in anaerobic sequencing batch reactors (AnSBR) were studied. Results showed that the hydrolysis over the cooked bagasse was more effective for sugar extraction at the studied conditions. Total sugars concentration in the cooked and uncooked bagasse hydrolysates were 27.9 g/L and 18.7 g/L, respectively. However, 5-hydroxymethylfurfural was detected in the cooked bagasse hydrolysate, and therefore, the uncooked bagasse hydrolysate was selected as substrate for methane production. Interestingly, results showed that the AnSBR operated without nutrient addition obtained a constant methane production (0.26 L CH4/g COD), whereas the AnSBR operated with nutrient addition presented a gradual methane suppression. Molecular analyses suggested that methane suppression in the experiment with nutrient addition was due to a negative effect over the archaeal/bacterial ratio. Copyright © 2015. Published by Elsevier Ltd.

Long-term effects of nickel oxide nanoparticles on performance, microbial enzymatic activity, and microbial community of a sequencing batch reactor.

PubMed

Wang, Sen; Li, Zhiwei; Gao, Mengchun; She, Zonglian; Guo, Liang; Zheng, Dong; Zhao, Yangguo; Ma, Bingrui; Gao, Feng; Wang, Xuejiao

2017-02-01

The nitrogen and phosphorus removal, microbial enzymatic activity, and microbial community of a sequencing batch reactor (SBR) were evaluated under long-term exposure to nickel oxide nanoparticles (NiO NPs). High NiO NP concentration (over 5 mg L -1 ) affected the removal of chemical oxygen demand, nitrogen, and phosphorus. The presence of NiO NP inhibited the microbial enzymatic activities and reduced the nitrogen and phosphorus removal rates of activated sludge. The microbial enzymatic activities of the activated sludge showed a similar variation trend to the nitrogen and phosphorus removal rates with the increase in NiO NP concentration from 0 to 60 mg L -1 . The Ni content in the effluent and activated sludge showed an increasing trend with the increase in NiO NP concentration. Some NiO NPs were absorbed on the sludge surface or penetrate the cell membrane into the interior of microbial cells in the activated sludge. NiO NP facilitated the increase in reactive oxygen species by disturbing the balance between the oxidation and anti-oxidation processes, and the variation in lactate dehydrogenase demonstrated that NiO NP could destroy the cytomembrane and cause variations in the microbial morphology and physiological function. High-throughput sequencing demonstrated that the microbial community of SBR had some obvious changes at 0-60 mg L -1 NiO NPs at the phyla, class and genus levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lactic acid production from potato peel waste by anaerobic sequencing batch fermentation using undefined mixed culture.

PubMed

Liang, Shaobo; McDonald, Armando G; Coats, Erik R

2015-11-01

Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L(-1), solids retention time of 2-4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g(-1) PPW and highest productivity of 125 mg g(-1) d(-1) were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L(-1) solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g(-1) PPW and a productivity of 138 mg g(-1) d(-1) were achieved with a 1 d SRT. Copyright © 2015 Elsevier Ltd. All rights reserved.

Strategies to evaluate biodegradability: application to chlorinated herbicides.

PubMed

Sanchis, S; Polo, A M; Tobajas, M; Rodriguez, J J; Mohedano, A F

2014-01-01

The biodegradability of nitrochlorinated (diuron and atrazine) and chlorophenoxy herbicides (2,4-D and MCPA) has been studied through several bioassays using different testing times and biomass/substrate ratios. A fast biodegradability test using unacclimated activated sludge yielded no biodegradation of the herbicides in 24 h. The inherent biodegradability test gave degradation percentages of around 20-30% for the nitrochlorinated herbicides and almost complete removal of the chlorophenoxy compounds. Long-term biodegradability assays were performed using sequencing batch reactor (SBR) and sequencing batch membrane bioreactor (SB-MBR). Fixed concentrations of each herbicide below the corresponding EC50 value for activated sludge were used (30 mg L(-1) for diuron and atrazine and 50 mg L(-1) for 2,4-D and MCPA). No signs of herbicide degradation appeared before 35 days in the case of diuron and atrazine and 21 days for 2,4-D, whereas MCPA was partially degraded since the early stages. Around 25-36% degradation of the nitrochlorinated herbicides and 53-77% of the chlorophenoxy ones was achieved after 180 and 135 days, respectively, in SBR, whereas complete disappearance of 2,4-D was reached after 80 days in SB-MBR.

A comparative study of methanol as a supplementary carbon source for enhancing denitrification in primary and secondary anoxic zones.

PubMed

Ginige, Maneesha P; Bowyer, Jocelyn C; Foley, Leah; Keller, Jürg; Yuan, Zhiguo

2009-04-01

A comparative study on the use of methanol as a supplementary carbon source to enhance denitrification in primary and secondary anoxic zones is reported. Three lab-scale sequencing batch reactors (SBR) were operated to achieve nitrogen and carbon removal from domestic wastewater. Methanol was added to the primary anoxic period of the first SBR, and to the secondary anoxic period of the second SBR. No methanol was added to the third SBR, which served as a control. The extent of improvement on the denitrification performance was found to be dependent on the reactor configuration. Addition to the secondary anoxic period is more effective when very low effluent nitrate levels are to be achieved and hence requires a relatively large amount of methanol. Adding a small amount of methanol to the secondary anoxic period may cause nitrite accumulation, which does not improve overall nitrogen removal. In the latter case, methanol should be added to the primary anoxic period. The addition of methanol can also improve biological phosphorus removal by creating anaerobic conditions and increasing the availability of organic carbon in wastewater for polyphosphate accumulating organisms. This potentially provides a cost-effective approach to phosphorus removal from wastewater with a low carbon content. New fluorescence in situ hybridisation (FISH) probes targeting methanol-utilising denitrifiers were designed using stable isotope probing. Microbial structure analysis of the sludges using the new and existing FISH probes clearly showed that the addition of methanol stimulated the growth of specific methanol-utilizing denitrifiers, which improved the capability of sludge to use methanol and ethanol for denitrification, but reduced its capability to use wastewater COD for denitrification. Unlike acetate, long-term application of methanol has no negative impact on the settling properties of the sludge.

Low acetate concentrations favor polyphosphate-accumulating organisms over glycogen-accumulating organisms in enhanced biological phosphorus removal from wastewater.

PubMed

Tu, Yunjie; Schuler, Andrew J

2013-04-16

Glycogen-accumulating organisms (GAOs) are thought to compete with polyphosphate-accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) wastewater treatment systems. A laboratory sequencing batch reactor (SBR) was operated for one year to test the hypothesis that PAOs have a competitive advantage at low acetate concentrations, with a focus on low pH conditions previously shown to favor GAOs. PAOs dominated the system under conventional SBR operation with rapid acetate addition (producing high in-reactor concentrations) and pH values of 7.4-8.4. GAOs dominated when the pH was decreased (6.4-7.0). Decreasing the acetate addition rate led to very low reactor acetate concentrations, and PAOs recovered, supporting the study hypothesis. When the acetate feed rate was increased, EBPR failed again. Dominant PAOs and GAOs were Candidatus Accumulibacter phosphatis and Defluviicoccus Cluster 2, respectively, according to fluorescent in situ hybridization and 454 pyrosequencing. Surprisingly, GAOs were not the immediate causes of PAO failures, based on functional and population measurements. Pyrosequencing results suggested Dechloromonas and Tetrasphaera spp. may have also been PAOs, and additional potential GAOs were also identified. Full-scale systems typically have lower in-reactor acetate concentrations than laboratory SBRs, and so, previous laboratory studies may have overestimated the practical importance of GAOs as causes of EBPR failure.

Performance evaluation of the sulfur-redox-reaction-activated up-flow anaerobic sludge blanket and down-flow hanging sponge anaerobic/anoxic sequencing batch reactor system for municipal sewage treatment.

PubMed

Hatamoto, Masashi; Ohtsuki, Kota; Maharjan, Namita; Ono, Shinya; Dehama, Kazuya; Sakamoto, Kenichi; Takahashi, Masanobu; Yamaguchi, Takashi

2016-03-01

A sulfur-redox-reaction-activated up-flow anaerobic sludge blanket (UASB) and down-flow hanging sponge (DHS) system, combined with an anaerobic/anoxic sequencing batch reactor (A2SBR), has been used for municipal sewage treatment for over 2 years. The present system achieved a removal rate of 95±14% for BOD, 74±22% for total nitrogen, and 78±25% for total phosphorus, including low water temperature conditions. Sludge conversion rates during the operational period were 0.016 and 0.218 g-VSS g-COD-removed(-1) for the UASB, and DHS, respectively, which are similar to a conventional UASB-DHS system, which is not used of sulfur-redox-reaction, for sewage treatment. Using the sulfur-redox reaction made advanced treatment of municipal wastewater with minimal sludge generation possible, even in winter. Furthermore, the occurrence of a unique phenomenon, known as the anaerobic sulfur oxidation reaction, was confirmed in the UASB reactor under the winter season. Copyright © 2016. Published by Elsevier Ltd.

Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

PubMed Central

Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

2015-01-01

Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3−-N could be removed or reduced, some amount of NO2−-N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy. PMID:26257096

Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor.

PubMed

Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

2015-08-10

Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3(-)-N could be removed or reduced, some amount of NO2(-)-N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

NASA Astrophysics Data System (ADS)

Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

2015-08-01

Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3--N could be removed or reduced, some amount of NO2--N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

Aerobic granulation in a modified oxidation ditch with an adjustable volume intraclarifier.

PubMed

Li, Jun; Cai, Ang; Wang, Miao; Ding, Libin; Ni, Yongjiong

2014-04-01

A modified oxidation ditch (MOD) with an adjustable volume intraclarifier was proposed and used to achieve aerobic sludge granulation in continuous flow process. This MOD with working volume of 60L treated onsite wastewater from a town. Excellent aerobic granules with mean diameter of 600μm and sludge volume index (SVI) of 44mL/g were obtained in 120day. Bacterial community analysis revealed that most species from seed sludge were preserved in both MOD and granule SBR (G-SBR) except bacteria (Bacteroidetes) might be easily washed out during granulation. Some different bacterial communities were found in sludges from sequencing batch and continuous flow reactors. Presence of metal ions and inorganics in raw wastewater had positive effect on granule formation, but an adjustable volume intraclarifier for controlling selection pressure and deleting return sludge pump played a key role in aerobic sludge granulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Treatment of oil-manufacturing wastewater by yeast-SBR system].

PubMed

Lü, Wen-zhou; Liu, Ying; Huang, Yi-zhen

2008-04-01

Eight yeast strains were applied to a sequencing batch reactor (SBR) to treat high-strength oil-containing wastewater. The removal performance, yeast cultivation method and key factors affecting the stability of system were discussed. The results show yeast sludge with MLSS of 19 g/L and SVI of 35 mL/g can be obtained in 6 d in an open system without any molds and bacteria inhibitor addition; In 30 d continuous wastewater treatment, COD and oil removal rate achieve 86.8%-96.9% and above 99.5% respectively under the influent conditions of the COD of 9000-23000 mg/L and oil of 4500-16000 mg/L; Short period of pH impact brings reversible effects on the system and the sludge retention time can affect the SVI of the yeast; Absence of nitrogen induces morphology conversion of some yeast cells from single cell to filamentous one and impairs the settling capability of the yeast.

Treatment of landfill leachate using a combined stripping, Fenton, SBR, and coagulation process.

PubMed

Guo, Jin-Song; Abbas, Abdulhussain A; Chen, You-Peng; Liu, Zhi-Ping; Fang, Fang; Chen, Peng

2010-06-15

The leachate from Changshengqiao landfill (Chongqing, China) was characterized and submitted to a combined process of air stripping, Fenton, sequencing batch reactor (SBR), and coagulation. Optimum operating conditions for each process were identified. The performance of the treatment was assessed by monitoring the removal of organic matter (COD and BOD(5)) and ammonia nitrogen (NH(3)-N). It has been confirmed that air stripping (at pH 11.0 and aeration time 18h) effectively removed 96.6% of the ammonia. The Fenton process was investigated under optimum conditions (pH 3.0, FeSO(4).7H(2)O of 20 g l(-1) and H(2)O(2) of 20 ml l(-1)), COD removal of up to 60.8% was achieved. Biodegradability (BOD(5)/COD ratio) increased from 0.18 to 0.38. Thereafter the Fenton effluent was mixed with sewage at dilutions to a ratio of 1:3 before it was subjected to the SBR reactor; under the optimum aeration time of 20 h, up to 82.8% BOD(5) removal and 83.1% COD removal were achieved. The optimum coagulant (Fe(2)(SO(4))(3)) was a dosage of 800 mg l(-1) at pH of 5.0, which reduced COD to an amount of 280 mg l(-1). These combined processes were successfully employed and very effectively decreased pollutant loading. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

In situ profiling of microbial communities in full-scale aerobic sequencing batch reactors treating winery waste in australia.

PubMed

McIlroy, Simon J; Speirs, Lachlan B M; Tucci, Joseph; Seviour, Robert J

2011-10-15

On-site aerobic sequencing batch reactor (SBR) treatment plants are implemented in many Australian wineries to treat the large volumes of associated wastewater they generate. Yet very little is known about their microbiology. This paper represents the first attempt to analyze the communities of three such systems sampled during both vintage and nonvintage operational periods using molecular methods. Alphaproteobacterial tetrad forming organisms (TFO) related to members of the genus Defluviicoccus and Amaricoccus dominated all three systems in both operational periods. Candidatus 'Alysiosphaera europaea' and Zoogloea were codominant in two communities. Production of high levels of exocellular capsular material by Zoogloea and Amaricoccus is thought to explain the poor settleability of solids in one of these plants. The dominance of these organisms is thought to result from the high COD to N/P ratios that characterize winery wastes, and it is suggested that manipulating this ratio with nutrient dosing may help control the problems they cause.

Dissolved oxygen as a key parameter to aerobic granule formation.

PubMed

Sturm, B S McSwain; Irvine, R L

2008-01-01

Much research has asserted that high shear forces are necessary for the formation of aerobic granular sludge in Sequencing Batch Reactors (SBRs). In order to distinguish the role of shear and dissolved oxygen on granule formation, two separate experiments were conducted with three bench-scale SBRs. In the first experiment, an SBR was operated with five sequentially decreasing superficial upflow gas velocities ranging from 1.2 to 0.4 cm s(-1). When less than 1 cm s(-1) shear was applied to the reactor, aerobic granules disintegrated into flocs, with corresponding increases in SVI and effluent suspended solids. However, the dissolved oxygen also decreased from 8 mg L(-1) to 5 mg L(-1), affecting the Feast/Famine regime in the SBR and the substrate removal kinetics. A second experiment operated two SBRs with an identical shear force of 1.2 cm s(-1), but two dissolved oxygen concentrations. Even when supplied a high shear force, aerobic granules could not form at a dissolved oxygen less than 5 mg L(-1), with a Static Fill. These results indicate that the substrate removal kinetics and dissolved oxygen are more significant to granule formation than shear force. Copyright IWA Publishing 2008.

Dry anaerobic digestion of high solids content dairy manure at high organic loading rates in psychrophilic sequence batch reactor.

PubMed

Massé, Daniel I; Saady, Noori M Cata

2015-05-01

Cow manure with bedding is renewable organic biomass available around the year on dairy farms. Developing efficient and cost-effective psychrophilic dry anaerobic digestion (PDAD) processes could contribute to solving farm-related environmental, energy, and manure management problems in cold-climate regions. This study was to increase the organic loading rate (OLR), fed to a novel psychrophilic (20 °C) dry anaerobic digestion of 27% total solid dairy manure (cow feces and wheat straw) in sequence batch reactor (PDAD-SBR), by 133 to 160%. The PDAD-SBR process operated at treatment cycle length of 21 days and OLR of 7.0 and 8.0 g total chemical oxygen demand (TCOD) kg(-1) inoculum day(-1) (5.2 ± 0.1 and 5.8 ± 0.0 g volatile solids (VS) kg(-1) inoculum day(-1)) for four successive cycles (84 days) produced average specific methane yields (SMYs) of 147.1 ± 17.2 and 143.2 ± 11.7 normalized liters (NL) CH4 kg(-1) VS fed, respectively. PDAD of cow feces and wheat straw is possible with VS-based inoculum-to-substrate ratio of 1.45 at OLR of 8.0 g TCOD kg(-1) inoculum day(-1). Hydrolysis was the limiting step reaction. The VS removal averaged around 57.4 ± 0.5 and 60.5 ± 5.7% at OLR 7.0 and 8.0 g TCOD kg(-1) inoculum day(-1), respectively.

Feeding schemes and C/N ratio of a laboratory-scale step-fed sequencing batch reactor for liquid swine manure treatment.

PubMed

Wu, Sarah Xiao; Zhu, Jun; Chen, Lide

2017-07-03

This study was undertaken to investigate the effect of two split feeding schemes (600 mL/200 mL and 400 mL/400 mL, designated as FS1 and FS2, respectively) on the performance of a step-fed sequencing batch reactor (SBR) in treating liquid swine manure for nutrient removal. The SBR was run on an 8-h cycle with a repeated pattern of anaerobic/anoxic/aerobic phases in each cycle and the two feedings always occurred at the beginning of each anaerobic phase. A low-level aeration was used (1.0 L/m 3 .sec) for the anoxic/aerobic phase to facilitate nitrification and phosphorus uptake while reducing the energy consumption. The results showed that FS1 reduced NH 4 + -N by 98.7% and FS2 by 98.3%. FS1 had 12.3 mg/L NO 3 -N left in the effluent, while FS2 had 4.51 mg/L. For soluble phosphorus removal, FS1 achieved 95.2%, while FS2 reached only 68.5%. Both feeding schemes achieved ≥ 95% removal of COD. A good power regression was observed between total nitrogen (sum of all three nitrogen species) and the carbon to nitrogen (C/N) ratio, with the correlation coefficients of 0.9729 and 0.9542 for FS1 and FS2, respectively, based on which it was concluded that higher C/N ratios were required to achieve higher nitrogen removal efficiencies.

A comparative study of occurrence and fate of endocrine disruptors: diethyl phthalate and dibutyl phthalate in ASP- and SBR-based wastewater treatment plants.

PubMed

Saini, Gita; Pant, Shalini; Singh, Shri Om; Kazmi, A A; Alam, Tanveer

2016-11-01

Phthalates are endocrine-disrupting chemicals which affect endocrine system by bio-accumulation in aquatic organisms and produce adverse health effects in aquatic organisms as well as human beings, when come in contact. Present study focuses on occurrence and removal of two phthalates: diethylphthalate (DEP) and dibutylphthalate (DBP) in two full-scale wastewater treatment plants (WWTPs) i.e. sewage treatment plants (STPs) based on well-adopted technologies, activated sludge process (ASP) and sequencing batch reactor (SBR).Gas chromatography-mass spectrometry (GC-MS) analysis was performed for both wastewater and sludge sample for determination and identification of the concentration of these compounds in both STPs by monitoring the STPs for 9 months. It was observed that the concentration of DEP was less than DBP in the influent of ASP and SBR. Average concentrations of DEP and DBP in sludge sample of ASP were found to be 2.15 and 2.08 ng/g, whereas in SBR plant, these values were observed as 1.71 and 2.01 ng/g, respectively. Concerning the removal efficiency of DEP, SBR and ASP plants were found effective with removal efficiency of 91.51 and 91.03 %, respectively. However, in the case of DBP, SBR showed lower removal efficiency (85.42 %) as compared to ASP (92.67 %). Comparative study of both plants proposed that in ASP plant, DBP reduction was higher than the SBR. Fourier transformation infrared (FTIR) analysis also confirmed the same result of sludge analysis for both STPs. Sludge disposal studied with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermo-gravimetric analysis (TGA) techniques confirmed that sludge of both STPs have high calorific value and can be used as fuel to make fuel-briquettes and bottom ash to make firebricks.

A comparison of anaerobic 2, 4-dichlorophenoxy acetic acid degradation in single-fed and sequencing batch reactor systems

NASA Astrophysics Data System (ADS)

Elefsiniotis, P.; Wareham, D. G.; Fongsatitukul, P.

2017-08-01

This paper compares the practical limits of 2, 4-dichlorophenoxy acetic acid (2,4-D) degradation that can be obtained in two laboratory-scale anaerobic digestion systems; namely, a sequencing batch reactor (SBR) and a single-fed batch reactor (SFBR) system. The comparison involved synthesizing a decade of research conducted by the lead author and drawing summative conclusions about the ability of each system to accommodate industrial-strength concentrations of 2,4-D. In the main, 2 L liquid volume anaerobic SBRs were used with glucose as a supplemental carbon source for both acid-phase and two-phase conditions. Volatile fatty acids however were used as a supplemental carbon source for the methanogenic SBRs. The anaerobic SBRs were operated at an hydraulic retention time of 48 hours, while being subjected to increasing concentrations of 2,4-D. The SBRs were able to degrade between 130 and 180 mg/L of 2,4-D depending upon whether they were operated in the acid-phase or two-phase regime. The methanogenic-only phase did not achieve 2,4-D degradation however this was primarily attributed to difficulties with obtaining a sufficiently long SRT. For the two-phase SFBR system, 3.5 L liquid-volume digesters were used and no difficulty was experienced with degrading 100 % of the 2,4-D concentration applied (300 mg/L).

Nitrite Interference with Soluble COD Measurements from Aerobically Treated Wastewater.

PubMed

Ferraz, Fernanda M; Yuan, Qiuyan

2017-06-01

  This study aimed to determine the interference of nitrite () with soluble chemical oxygen demand (COD) measurements from the effluent of landfill leachate treated by sequencing batch reactors (SBRs). Synthetic wastewater assimilating young and old landfill leachate was used as influent for SBR1 and SBR2, respectively. A mixture of raw wastewater and landfill leachate was used as influent for SBR3. Due to the high ammonia concentration in the influent, different levels of partial nitrification were observed in all the reactors and was detected in the effluents. Theoretically, when is present in the effluent, 1 mg/L of accounts for 1.1 mg/L of COD (i.e., 1.1 mg COD/mg ) due to the oxidation of to . It was found that the value of 1.1 mg COD/mg was 3 times higher than the values obtained in the experiments with SBR1 and SBR3. In addition, the values obtained in the experiments with SBR2 were much higher than 1.1 mg COD/mg . These results suggest that the theoretical value of 1.1 mg COD/mg cannot be applied to predict the COD values caused by nitrite in the tested wastewaters. To obtain an accurate measurement of soluble COD in samples that contain nitrite, nitrite should be eliminated before the measurements.

Source identification of nitrous oxide on autotrophic partial nitrification in a granular sludge reactor.

PubMed

Rathnayake, R M L D; Song, Y; Tumendelger, A; Oshiki, M; Ishii, S; Satoh, H; Toyoda, S; Yoshida, N; Okabe, S

2013-12-01

Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern since N2O is a major stratospheric ozone-depleting substance and an important greenhouse gas. The emission of N2O from a lab-scale granular sequencing batch reactor (SBR) for partial nitrification (PN) treating synthetic wastewater without organic carbon was therefore determined in this study, because PN process is known to produce more N2O than conventional nitrification processes. The average N2O emission rate from the SBR was 0.32 ± 0.17 mg-N L(-1) h(-1), corresponding to the average emission of N2O of 0.8 ± 0.4% of the incoming nitrogen load (1.5 ± 0.8% of the converted NH4(+)). Analysis of dynamic concentration profiles during one cycle of the SBR operation demonstrated that N2O concentration in off-gas was the highest just after starting aeration whereas N2O concentration in effluent was gradually increased in the initial 40 min of the aeration period and was decreased thereafter. Isotopomer analysis was conducted to identify the main N2O production pathway in the reactor during one cycle. The hydroxylamine (NH2OH) oxidation pathway accounted for 65% of the total N2O production in the initial phase during one cycle, whereas contribution of the NO2(-) reduction pathway to N2O production was comparable with that of the NH2OH oxidation pathway in the latter phase. In addition, spatial distributions of bacteria and their activities in single microbial granules taken from the reactor were determined with microsensors and by in situ hybridization. Partial nitrification occurred mainly in the oxic surface layer of the granules and ammonia-oxidizing bacteria were abundant in this layer. N2O production was also found mainly in the oxic surface layer. Based on these results, although N2O was produced mainly via NH2OH oxidation pathway in the autotrophic partial nitrification reactor, N2O production mechanisms were complex and could involve multiple N2O production pathways. Copyright © 2013 Elsevier Ltd. All rights reserved.

Performance of aerobic nitrite granules treating an anaerobic pre-treated wastewater originating from the potato industry.

PubMed

Dobbeleers, Thomas; Daens, Dominique; Miele, Solange; D'aes, Jolien; Caluwé, Michel; Geuens, Luc; Dries, Jan

2017-02-01

In this study nitrogen removal via nitrite >80% was achieved after approximately 80days in a sequencing batch reactor (SBR) treating pre-treated industrial wastewater originating from the potato industry. Thereafter, SBR performance was investigated during the formation of aerobic nitrite granules (ANG). The first granules appeared after 26days leading to full granulation after 64days. ANG showed excellent settling properties, as the Sludge Volume Index (SVI) went down to 16mL/g and a SVI 10 /SVI 30 =1 was obtained. qPCR analysis showed that slow growing organisms, especially polyphosphate accumulating organisms (PAO) were stimulated by an anaerobic feeding strategy. The average nitrogen removal was 95.3% over the entire operational period, and it mainly followed the "nitrite-route". Moreover, with ANG also phosphorus removal efficiencies up to 65.7% could be achieved. However, it has to be mentioned that nitrous oxide was an important denitrification product, which implies some environmental concerns. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of key microbial community during the start-up of anaerobic ammonium oxidation process with paddy soil as inoculated sludge.

PubMed

Xu, Xianglong; Liu, Guohua; Wang, Yuanyuan; Zhang, Yuankai; Wang, Hao; Qi, Lu; Wang, Hongchen

2018-02-01

A sequencing batch reactor (SBR)-anaerobic ammonium oxidation (anammox) system was started up with the paddy soil as inoculated sludge. The key microbial community structure in the system along with the enrichment time was investigated by using molecular biology methods (e.g., high-throughput 16S rRNA gene sequencing and quantitative PCR). Meanwhile, the influent and effluent water quality was continuously monitored during the whole start-up stage. The results showed that the microbial diversity decreased as the operation time initially and increased afterwards, and the microbial niches in the system were redistributed. The anammox bacterial community structure in the SBR-anammox system shifted during the enrichment, the most dominant anammox bacteria were CandidatusJettenia. The maximum biomass of anammox bacteria achieved 1.68×10 9 copies/g dry sludge during the enrichment period, and the highest removal rate of TN achieved around 75%. Copyright © 2017. Published by Elsevier B.V.

Biodegradability of leachates from Chinese and German municipal solid waste*

PubMed Central

Selic, E.; Wang, Chi; Boes, N.; Herbell, J.D.

2007-01-01

The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600 000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water. PMID:17173357

Biodegradability of leachates from Chinese and German municipal solid waste.

PubMed

Selic, E; Wang, Chi; Boes, N; Herbell, J D

2007-01-01

The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600 000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water.

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

PubMed

Farabegoli, G; Chiavola, A; Rolle, E

2012-01-01

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

Accelerating Aerobic Sludge Granulation by Adding Dry Sewage Sludge Micropowder in Sequencing Batch Reactors

PubMed Central

Li, Jun; Liu, Jun; Wang, Danjun; Chen, Tao; Ma, Ting; Wang, Zhihong; Zhuo, Weilong

2015-01-01

Micropowder (20–250 µm) made from ground dry waste sludge from a municipal sewage treatment plant was added in a sequencing batch reactor (R2), which was fed by synthetic wastewater with acetate as carbon source. Compared with the traditional SBR (R1), aerobic sludge granulation time was shortened 15 days in R2. Furthermore, filamentous bacteria in bulking sludge were controlled to accelerate aerobic granulation and form large granules. Correspondingly, the SVI decreased from 225 mL/g to 37 mL/g. X-ray Fluorescence (XRF) analysis demonstrated that Al and Si from the micropowder were accumulated in granules. A mechanism hypotheses for the acceleration of aerobic granulation by adding dry sludge micropowder is proposed: added micropowder acts as nuclei to induce bacterial attachment; dissolved matters from the micropowder increase abruptly the organic load for starved sludge to control overgrown filamentous bacteria as a framework for aggregation; increased friction from the movement of micropowder forces the filaments which extend outwards to shrink for shaping granules. PMID:26308025

Optimisation potential for a SBR plant based upon integrated modelling for dry and wet weather conditions.

PubMed

Rönner-Holm, S G E; Kaufmann Alves, I; Steinmetz, H; Holm, N C

2009-01-01

Integrated dynamic simulation analysis of a full-scale municipal sequential batch reactor (SBR) wastewater treatment plant (WWTP) was performed using the KOSMO pollution load simulation model for the combined sewer system (CSS) and the ASM3 + EAWAG-BioP model for the WWTP. Various optimising strategies for dry and storm weather conditions were developed to raise the purification and hydraulic performance and to reduce operation costs based on simulation studies with the calibrated WWTP model. The implementation of some strategies on the plant led to lower effluent values and an average annual saving of 49,000 euro including sewage tax, which is 22% of the total running costs. Dynamic simulation analysis of CSS for an increased WWTP influent over a period of one year showed high potentials for reducing combined sewer overflow (CSO) volume by 18-27% and CSO loads for COD by 22%, NH(4)-N and P(total) by 33%. In addition, the SBR WWTP could easily handle much higher influents without exceeding the monitoring values. During the integrated simulation of representative storm events, the total emission load for COD dropped to 90%, the sewer system emitted 47% less, whereas the pollution load in the WWTP effluent increased to only 14% with 2% higher running costs.

Treatability studies with granular activated carbon (GAC) and sequencing batch reactor (SBR) system for textile wastewater containing direct dyes.

PubMed

Sirianuntapiboon, Suntud; Sansak, Jutarat

2008-11-30

The GAC-SBR efficiency was decreased with the increase of dyestuff concentration or the decrease of bio-sludge concentration. The system showed the highest removal efficiency with synthetic textile wastewater (STWW) containing 40 mg/L direct red 23 or direct blue 201 under MLSS of 3,000 mg/L and hydraulic retention time (HRT) of 7.5 days. But, the effluent NO(3)(-) was higher than that of the influent. Direct red 23 was more effective than direct blue 201 to repress the GAC-SBR system efficiency. The dyes removal efficiency of the system with STWW containing direct red 23 was reduced by 30% with the increase of direct red 23 from 40 mg/L to 160 mg/L. The system with raw textile wastewater (TWW) showed quite low BOD(5) TKN and dye removal efficiencies of only 64.7+/-4.9% and 50.2+/-6.9%, respectively. But its' efficiencies could be increased by adding carbon sources (BOD(5)). The dye removal efficiency with TWW was increased by 30% and 20% by adding glucose (TWW+glucose) or Thai rice noodle wastewater (TWW+TRNWW), respectively. SRT of the systems were 28+/-1 days and 31+/-2 days with TWW+glucose and TWW+TRNWW, respectively.

Effect of Free Ammonia, Free Nitrous Acid, and Alkalinity on the Partial Nitrification of Pretreated Pig Slurry, Using an Alternating Oxic/Anoxic SBR

PubMed Central

Hsieh, Chia-Fang; Guerrero, Lorna; Méndez, Ramón; Mosquera-Corral, Anuska; Vidal, Gladys

2017-01-01

The effect of free ammonia (NH3 or FA), free nitrous acid (HNO2 or FNA), and total alkalinity (TA) on the performance of a partial nitrification (PN) sequencing batch reactor (SBR) treating anaerobically pretreated pig slurry was studied. The SBR was operated under alternating oxic/anoxic (O/A) conditions and was fed during anoxic phases. This strategy allowed using organic matter to partially remove nitrite (NO2−) and nitrate (NO3−) generated during oxic phases. The desired NH4+ to NO2− ratio of 1.3 g N/g N was obtained when an Ammonium Loading Rate (ALR) of 0.09 g NH4+-N/L·d was applied. The system was operated at a solid retention time (SRT) of 15–20 d and dissolved oxygen (DO) levels higher than 3 mg O2/L during the whole operational period. PN mainly occurred caused by the inhibitory effect of FNA on nitrite oxidizing bacteria (NOB). Once HNO2 concentration was negligible, NH4+ was fully oxidized to NO3− in spite of the presence of FA. The use of biomass acclimated to ammonium as inoculum avoided a possible effect of FA on NOB activity. PMID:29018815

Effect of COD/N ratio on N2O production during nitrogen removal by aerobic granular sludge.

PubMed

Velho, V F; Magnus, B S; Daudt, G C; Xavier, J A; Guimarães, L B; Costa, R H R

2017-12-01

N 2 O-production was investigated during nitrogen removal using aerobic granular sludge (AGS) technology. A pilot sequencing batch reactor (SBR) with AGS achieved an effluent in accordance with national discharge limits, although presented a nitrite accumulation rate of 95.79% with no simultaneous nitrification-denitrification. N 2 O production was 2.06 mg L -1 during the anoxic phase, with N 2 O emission during air pulses and the aeration phase of 1.6% of the nitrogen loading rate. Batch tests with AGS from the pilot reactor verified that at the greatest COD/N ratio (1.55), the N 2 O production (1.08 mgN 2 O-N L -1 ) and consumption (up to 0.05 mgN 2 O-N L -1 ), resulted in the lowest remaining dissolved N 2 O (0.03 mgN 2 O-N L -1 ), stripping the minimum N 2 O gas (0.018 mgN 2 O-N L -1 ). Conversely, the carbon supply shortage, under low C/N ratios, increased N 2 O emission (0.040 mgN 2 O-N L -1 ), due to incomplete denitrification. High abundance of ammonia-oxidizing and low abundance of nitrite-oxidizing bacteria were found, corroborating the fact of partial nitrification. A denitrifying heterotrophic community, represented mainly by Pseudoxanthomonas, was predominant in the AGS. Overall, the AGS showed stable partial nitrification ability representing capital and operating cost savings. The SBR operation flexibility could be advantageous for controlling N 2 O emissions, and extending the anoxic phase would benefit complete denitrification in cases of low C/N influents.

Complete and simultaneous removal of ammonium and m-cresol in a nitrifying sequencing batch reactor.

PubMed

Zepeda, Alejandro; Ben-Youssef, Chérif; Rincón, Susana; Cuervo-López, Flor; Gómez, Jorge

2013-06-01

The kinetic behavior, oxidizing ability and tolerance to m-cresol of a nitrifying sludge exposed to different initial concentrations of m-cresol (0-150 mg C L(-1)) were evaluated in a sequencing batch reactor fed with 50 mg NH4 (+)-N L(-1) and operated during 4 months. Complete removal of ammonium and m-cresol was achieved independently of the initial concentration of aromatic compound in all the assays. Up to 25 mg m-cresol-C L(-1) (C/N ratio of 0.5), the nitrifying yield (Y-NO3 (-)) was 0.86 ± 0.05, indicating that the nitrate was the main product of the process; no biomass growth was detected. From 50 to 150 mg m-cresol-C L(-1) (1.0 ≤ C/N ≤ 3.0), simultaneous microbial growth and partial ammonium-to-nitrate conversion were obtained, reaching a maximum microbial total protein concentration of 0.763 g L(-1) (247 % of its initial value) and the lowest Y-NO3 (-) 0.53 ± 0.01 at 150 mg m-cresol-C L(-1). m-Cresol induced a significant decrease in the values of both specific rates of ammonium and nitrite oxidation, being the ammonium oxidation pathway the mainly inhibited. The nitrifying sludge was able to completely oxidize up to 150 mg m-cresol-C L(-1) by SBR cycle, reaching a maximum specific removal rate of 6.45 g m-cresol g(-1) microbial protein-N h(-1). The number of SBR cycles allowed a metabolic adaptation of the nitrifying consortium since nitrification inhibition decreased and faster oxidation of m-cresol took place throughout the cycles.

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.

Modeling the competition between PHA-producing and non-PHA-producing bacteria in feast-famine SBR and staged CSTR systems.

PubMed

Marang, Leonie; van Loosdrecht, Mark C M; Kleerebezem, Robbert

2015-12-01

Although the enrichment of specialized microbial cultures for the production of polyhydroxyalkanoates (PHA) is generally performed in sequencing batch reactors (SBRs), the required feast-famine conditions can also be established using two or more continuous stirred-tank reactors (CSTRs) in series with partial biomass recirculation. The use of CSTRs offers several advantages, but will result in distributed residence times and a less strict separation between feast and famine conditions. The aim of this study was to investigate the impact of the reactor configuration, and various process and biomass-specific parameters, on the enrichment of PHA-producing bacteria. A set of mathematical models was developed to predict the growth of Plasticicumulans acidivorans-as a model PHA producer-in competition with a non-storing heterotroph. A macroscopic model considering lumped biomass and an agent-based model considering individual cells were created to study the effect of residence time distribution and the resulting distributed bacterial states. The simulations showed that in the 2-stage CSTR system the selective pressure for PHA-producing bacteria is significantly lower than in the SBR, and strongly affected by the chosen feast-famine ratio. This is the result of substrate competition based on both the maximum specific substrate uptake rate and substrate affinity. Although the macroscopic model overestimates the selective pressure in the 2-stage CSTR system, it provides a quick and fairly good impression of the reactor performance and the impact of process and biomass-specific parameters. © 2015 Wiley Periodicals, Inc.

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

PubMed

Wu, Sarah Xiao; Maskaly, Jason

2018-01-28

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

Effects of 4-chlorophenol wastewater treatment on sludge acute toxicity, microbial diversity and functional genes expression in an activated sludge process.

PubMed

Zhao, Jianguo; Li, Yahe; Li, Yu; Yu, Zeya; Chen, Xiurong

2018-05-31

In this study, the effects of 4-chlorophenol (4-CP) wastewater treatment on sludge acute toxicity of luminescent bacteria, microbial diversity and functional genes expression of Pseudomonas were explored. Results showed that in the entire operational process, the sludge acute toxicity acclimated by 4-CP in a sequencing batch bioreactor (SBR) was significantly higher than the control SBR without 4-CP. The dominant phyla in acclimated SBR were Proteobacteria and Firmicutes, which also existed in control SBR. Some identified genera in acclimated SBR were responsible for 4-CP degradation. At the stable operational stages, the functional genes expression of Pseudomonas in acclimated SBR was down-regulated at the end of SBR cycle, and their expression mechanisms needed further research. This study provides a theoretical support to comprehensively understand the sludge performance in industrial wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multi-cycle operation of enhanced biological phosphorus removal (EBPR) with different carbon sources under high temperature.

PubMed

Shen, Nan; Chen, Yun; Zhou, Yan

2017-05-01

Many studies reported that it is challenging to apply enhanced biological phosphorus removal (EBPR) process at high temperature. Glycogen accumulating organisms (GAOs) could easily gain their dominance over poly-phosphate accumulating organisms (PAOs) when the operating temperature was in the range of 25 °C-30 °C. However, a few successful EBPR processes operated at high temperature have been reported recently. This study aimed to have an in-depth understanding on the impact of feeding strategy and carbon source types on EBPR performance in tropical climate. P-removal performance of two EBPR systems was monitored through tracking effluent quality and cyclic studies. The results confirmed that EBPR was successfully obtained and maintained at high temperature with a multi-cycle strategy. More stable performance was observed with acetate as the sole carbon source compared to propionate. Stoichiometric ratios of phosphorus and carbon transformation during both anaerobic and aerobic phases were higher at high temperature than low temperature (20±1 °C) except anaerobic PHA/C ratios within most of the sub-cycles. Furthermore, the fractions of PHA and glycogen in biomass were lower compared with one-cycle pulse feed operation. The microbial community structure was more stable in acetate-fed sequencing batch reactor (C2-SBR) than that in propionate-fed reactor (C3-SBR). Accumulibacter Clade IIC was found to be highly abundant in both reactors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of dairy wastewater on changes in COD fractions in technical-scale SBR type reactors.

PubMed

Struk-Sokołowska, Joanna; Rodziewicz, Joanna; Mielcarek, Artur

2017-04-01

The annual global production of milk is approximately 630,000 million litres and the volume of generated dairy wastewater accounts for 3.2 m 3 ·m -3 product. Dairy wastewater is characterized by a high load of chemical oxygen demand (COD). In many wastewater plants dairy wastewater and municipal wastewater are co-treated. The effect of dairy wastewater contribution on COD fraction changes in municipal sewage which has been treated with a sequencing batch reactor (SBR) in three wastewater treatment plants in north-east Poland is presented. In these plants the real contribution of dairy wastewater was 10, 13 and 17%. In raw wastewater, S S fraction (readily biodegradable dissolved organic matter) was dominant and ranged from 38.3 to 62.6%. In the effluent, S S fraction was not noted, which is indicative of consumption by microorganisms. The presence of dairy wastewater in municipal sewage does not cause changes in the content of the X I fraction (insoluble fractions of non-biodegradable organic matter). SBR effluents were dominated by non-biodegradable dissolved organic matter S I , which from 57.7 to 61.7%. In raw wastewater S I ranged from 1.0 to 4.6%. X s fraction (slowly biodegradable non-soluble organic matter) in raw wastewater ranged from 24.6 to 45.5% while in treated wastewater it ranged from 28.6 to 30.8%. In the control object (fourth wastewater plant) which does not process dairy wastewater, the S S , S I , X s and X I fraction in inflow was 28.7, 2.4, 51.7 and 17.2% respectively. In the effluent the S S , S I , X s and X I fraction was below 0.1, 33.6, 50.0 and 16.4% respectively.

Operating aerobic wastewater treatment at very short sludge ages enables treatment and energy recovery through anaerobic sludge digestion.

PubMed

Ge, Huoqing; Batstone, Damien J; Keller, Jurg

2013-11-01

Conventional abattoir wastewater treatment processes for carbon and nutrient removal are typically designed and operated with a long sludge retention time (SRT) of 10-20 days, with a relatively high energy demand and physical footprint. The process also generates a considerable amount of waste activated sludge that is not easily degradable due to the long SRT. In this study, an innovative high-rate sequencing batch reactor (SBR) based wastewater treatment process with short SRT and hydraulic retention time (HRT) is developed and characterised. The high-rate SBR process was shown to be most effective with SRT of 2-3 days and HRT of 0.5-1 day, achieving >80% reduction in chemical oxygen demand (COD) and phosphorus and approximately 55% nitrogen removal. A majority of carbon removal (70-80%) was achieved by biomass assimilation and/or accumulation, rather than oxidation. Anaerobic degradability of the sludge generated in the high-rate SBR process was strongly linked to SRT, with measured degradability extent being 85% (2 days SRT), 73% (3 days), and 63% (4 days), but it was not influenced by digestion temperature. However, the rate of degradation for 3 and 4 days SRT sludge was increased by 45% at thermophilic conditions compared to mesophilic conditions. Overall, the treatment process provides a very compact and energy efficient treatment option for highly degradable wastewaters such as meat and food processing, with a substantial space reduction by using smaller reactors and a considerable net energy output through the reduced aerobic oxidation and concurrent increased methane production potential through the efficient sludge digestion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Performance of enhanced biological SBR process for aniline treatment by mycelial pellet as biomass carrier.

PubMed

Zhang, Si; Li, Ang; Cui, Di; Yang, Jixian; Ma, Fang

2011-03-01

Mycelial pellet of Aspergillus niger Y3 was used as a biomass carrier to immobilize the aniline-degrading bacterium, Acinetobacter calcoaceticus JH-9 and the mix culture of the COD rapid degradation bacteria. In order to investigate its removal effect on aniline and COD, the combined mycelial pellets were applied in the SBR. Comparison of the performances was conducted between another SBR inoculated with sole strain JH-9 and the above SBR. The results showed that the stable degradations of aniline and COD were observed in both reactors. In the SBR with combined mycelial pellet, the biological removal efficiency was about 0.9 mg aniline/(L·d). It was much higher than that in the activated sludge reactor. Meanwhile, the performances of the sedimentation velocity, liquid-solid phase separation and the effluent quality were better in the SBR. According to SEM images and PCR-DGGE analysis, the species immobilized on the biomass carrier were more predominant in this system. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

PubMed

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

2012-01-01

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

Nitrogen and phosphorus treatment of marine wastewater by a laboratory-scale sequencing batch reactor with eco-friendly marine high-efficiency sediment.

PubMed

Cho, Seonghyeon; Kim, Jinsoo; Kim, Sungchul; Lee, Sang-Seob

2017-06-22

We screened and identified a NH 3 -N-removing bacterial strain, Bacillus sp. KGN1, and a [Formula: see text] removing strain, Vibrio sp. KGP1, from 960 indigenous marine isolates from seawater and marine sediment from Tongyeong, South Korea. We developed eco-friendly high-efficiency marine sludge (eco-HEMS), and inoculated these marine bacterial strains into the marine sediment. A laboratory-scale sequencing batch reactor (SBR) system using the eco-HEMS for marine wastewater from land-based fish farms improved the treatment performance as indicated by 88.2% removal efficiency (RE) of total nitrogen (initial: 5.6 mg/L) and 90.6% RE of total phosphorus (initial: 1.2 mg/L) under the optimal operation conditions (food and microorganism (F/M) ratio, 0.35 g SCOD Cr /g mixed liquor volatile suspended solids (MLVSS)·d; dissolved oxygen (DO) 1.0 ± 0.2 mg/L; hydraulic retention time (HRT), 6.6 h; solids retention time (SRT), 12 d). The following kinetic parameters were obtained: cell yield (Y), 0.29 g MLVSS/g SCOD Cr ; specific growth rate (µ), 0.06 d -1 ; specific nitrification rate (SNR), 0.49 mg NH 3 -N/g MLVSS·h; specific denitrification rate (SDNR), 0.005 mg [Formula: see text]/g MLVSS·h; specific phosphorus uptake rate (SPUR), 0.12 mg [Formula: see text]/g MLVSS·h. The nitrogen- and phosphorus-removing bacterial strains comprised 18.4% of distribution rate in the microbial community of eco-HEMS under the optimal operation conditions. Therefore, eco-HEMS effectively removed nitrogen and phosphorus from highly saline marine wastewater from land-based fish farms with improving SNR, SDNR, and SPUR values in more diverse microbial communities. DO: dissolved oxygen; Eco-HEMS: eco-friendly high efficiency marine sludge; F/M: food and microorganism ratio; HRT: hydraulic retention time; ML(V)SS: mixed liquor (volatile) suspended solids; NCBI: National Center for Biotechnology Information; ND: not determined; qPCR: quantitative real-time polymerase chain reaction; RE: removal efficiency; SBR: sequencing batch reactor; SD: standard deviation; SDNR: specific denitrification rate; SNR: specific nitrification rate; SPUR: specific phosphate uptake rate; SRT: solids retention time; T-N: total nitrogen; T-P: total phosphorus; (V)SS: (volatile) suspended solids; w.w.: wet weight.

[Research on change process of nitrosation granular sludge in continuous stirred-tank reactor].

PubMed

Yin, Fang-Fang; Liu, Wen-Ru; Wang, Jian-Fang; Wu, Peng; Shen, Yao-Liang

2014-11-01

In order to investigate the effect of different types of reactors on the nitrosation granular sludge, a continuous stirred-tank reactor (CSTR) was studied, using mature nitrosation granular sludge cultivated in sequencing batch reactor (SBR) as seed sludge. Results indicated that the change of reactor type and influent mode could induce part of granules to lose stability with gradual decrease in sludge settling ability during the initial period of operation. However, the flocs in CSTR achieved fast granulation in the following reactor operation. In spite of the changes of particle size distribution, e. g. the decreasing number of granules with diameter larger than 2.5 mm and the increasing number of granules with diameter smaller than 0.3 mm, granular sludge held the absolute predominance of sludge morphology in CSTR during the entire experimental period. Moreover, results showed that the change of reactor type and influent mode didn't affect the nitrite accumulation rate which was still kept at about 85% in effluent. Additionally, the average activity of the sludge in CSTR was stronger than that of the seed sludge, because the newly generated small particles in CSTR had higher specific reactive activity than the larger granules.

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

The peroxidase-mediated biodegradation of petroleum hydrocarbons in a H2O2-induced SBR using in-situ production of peroxidase: Biodegradation experiments and bacterial identification.

PubMed

Shekoohiyan, Sakine; Moussavi, Gholamreza; Naddafi, Kazem

2016-08-05

A bacterial peroxidase-mediated oxidizing process was developed for biodegrading total petroleum hydrocarbons (TPH) in a sequencing batch reactor (SBR). Almost complete biodegradation (>99%) of high TPH concentrations (4g/L) was attained in the bioreactor with a low amount (0.6mM) of H2O2 at a reaction time of 22h. A specific TPH biodegradation rate as high as 44.3mgTPH/gbiomass×h was obtained with this process. The reaction times required for complete biodegradation of TPH concentrations of 1, 2, 3, and 4g/L were 21, 22, 28, and 30h, respectively. The catalytic activity of hydrocarbon catalyzing peroxidase was determined to be 1.48U/mL biomass. The biodegradation of TPH in seawater was similar to that in fresh media (no salt). A mixture of bacteria capable of peroxidase synthesis and hydrocarbon biodegradation including Pseudomonas spp. and Bacillus spp. were identified in the bioreactor. The GC/MS analysis of the effluent indicated that all classes of hydrocarbons could be well-degraded in the H2O2-induced SBR. Accordingly, the peroxidase-mediated process is a promising method for efficiently biodegrading concentrated TPH-laden saline wastewater. Copyright © 2016 Elsevier B.V. All rights reserved.

Formation of aerobic granular sludge and the influence of the pH on sludge characteristics in a SBR fed with brewery/bottling plant wastewater.

PubMed

Stes, Hannah; Aerts, Sven; Caluwé, Michel; Dobbeleers, Thomas; Wuyts, Sander; Kiekens, Filip; D'aes, Jolien; De Langhe, Piet; Dries, Jan

2018-05-01

A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic granule formation when treating brewery/bottling plant wastewater by consistent application of a feast/famine regime. The experiment was divided into three major periods according to the different operational conditions: (I) no pH control and strong fluctuations in organic loading rate (OLR) (1.18 ± 0.25 kgCOD·(m 3 ·day) -1 ), (II) pH control and aeration control strategy to reduce OLR fluctuations (1.45 ± 0.65 kgCOD·(m 3 ·day) -1 ) and (III) no pH control and stable OLR (1.42 ± 0.18 kgCOD·(m 3 ·day) -1 ). Aerobic granule formation was successful after 80 days and maintained during the subsequent 380 days. The aerobic granular sludge was characterized by SVI 5 and SVI 30 values below 60 mL.g -1 and dominated by granular, dense structures. An oxygen uptake rate based aeration control strategy insured endogenous respiration at the end of the aerobic phase, resulting in stable SBR operation when the influent composition fluctuated. The quantitative polymerase chain reaction results show no significant enrichment of Accumulibacter or Competibacter during the granulation process. The 16S rRNA sequencing results indicate enrichment of other, possibly important species during aerobic granule formation while treating brewery wastewaters.

Treatment of synthetic kraft evaporator condensate using thermophilic and mesophilic membrane aerated biofilm reactors.

PubMed

Liao, B Q; Zheng, M R; Ratana-Rueangsri, L

2010-01-01

A comparative study on the treatment of synthetic kraft evaporator condensate was conducted using thermophilic (55 degrees C) and mesophilic (30 degrees C) membrane aerated biofilm reactors (MABRs) and sequencing batch reactors (SBRs) for 8 months. Under tested conditions, a chemical oxygen demand (COD) removal efficiency of 80-95% was achieved with both thermophilic and mesophilic MABRs and SBRs. The COD removal efficiency of thermophilic MABR (80-90%) was slightly lower than that of the mesophilic MABR (85-95%) and the thermophilic SBR (90-95%). A significant amount (13-37%) of COD was stripped by conventional aeration in the SBRs, while stripping in MABRs was negligible. Simultaneous COD removal and denitrification were observed in the mesophilic MABR, while the thermophilic MABR contributed mainly for COD removal. Nitrification was not significant in both the thermophilic and mesophilic MABRs. The results suggest that treatment of kraft evaporator condensate is feasible with the use of both thermophilic and mesophilic MABRs in terms of COD removal with the advantages of negligible stripping.

Assessment of UASB-DHS technology for sewage treatment: a comparative study from a sustainability perspective.

PubMed

Maharjan, Namita; Nomoto, Naoki; Tagawa, Tadashi; Okubo, Tsutomu; Uemura, Shigeki; Khalil, Nadeem; Hatamoto, Masashi; Yamaguchi, Takashi; Harada, Hideki

2018-04-06

This paper assesses the technical and economic sustainability of a combined system of an up-flow anaerobic sludge blanket (UASB)-down-flow hanging sponge (DHS) for sewage treatment. Additionally, this study compares UASB-DHS with current technologies in India like trickling filters (TF), sequencing batch reactor (SBR), moving bed biofilm reactor (MBBR), and other combinations of UASB with post-treatment systems such as final polishing ponds (FPU) and extended aeration sludge process (EASP). The sustainability of the sewage treatment plants (STPs) was evaluated using a composite indicator, which incorporated environmental, societal, and economic dimensions. In case of the individual sustainability indicator study, the results showed that UASB-FPU was the most economically sustainable system with a score of 0.512 and aeration systems such as MBBR, EASP, and SBR were environmentally sustainable, whereas UASB-DHS system was socially sustainable. However, the overall comparative analysis indicated that the UASB-DHS system scored the highest value of 2.619 on the global sustainability indicator followed by EASP and MBBR with scores of 2.322 and 2.279, respectively. The highlight of this study was that the most environmentally sustainable treatment plants were not economically and socially sustainable. Moreover, sensitivity analysis showed that five out of the seven scenarios tested, the UASB-DHS system showed good results amongst the treatment system.

Application of gas sensor arrays in assessment of wastewater purification effects.

PubMed

Guz, Łukasz; Łagód, Grzegorz; Jaromin-Gleń, Katarzyna; Suchorab, Zbigniew; Sobczuk, Henryk; Bieganowski, Andrzej

2014-12-23

A gas sensor array consisting of eight metal oxide semiconductor (MOS) type gas sensors was evaluated for its ability for assessment of the selected wastewater parameters. Municipal wastewater was collected in a wastewater treatment plant (WWTP) in a primary sedimentation tank and was treated in a laboratory-scale sequential batch reactor (SBR). A comparison of the gas sensor array (electronic nose) response to the standard physical-chemical parameters of treated wastewater was performed. To analyze the measurement results, artificial neural networks were used. E-nose-gas sensors array and artificial neural networks proved to be a suitable method for the monitoring of treated wastewater quality. Neural networks used for data validation showed high correlation between the electronic nose readouts and: (I) chemical oxygen demand (COD) (r = 0.988); (II) total suspended solids (TSS) (r = 0.938); (III) turbidity (r = 0.940); (IV) pH (r = 0.554); (V) nitrogen compounds: N-NO3 (r = 0.958), N-NO2 (r = 0.869) and N-NH3 (r = 0.978); (VI) and volatile organic compounds (VOC) (r = 0.987). Good correlation of the abovementioned parameters are observed under stable treatment conditions in a laboratory batch reactor.

Mixed culture polyhydroxyalkanoates production from sugar molasses: the use of a 2-stage CSTR system for culture selection.

PubMed

Albuquerque, M G E; Concas, S; Bengtsson, S; Reis, M A M

2010-09-01

Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers. The use of mixed microbial cultures (MMC) and low cost feedstocks have a positive impact on the cost-effectiveness of the process. It has typically been carried out in Sequencing Batch Reactors (SBR). In this study, a 2-stage CSTR system (under Feast and Famine conditions) was used to effectively select for PHA-storing organisms using fermented molasses as feedstock. The effect of influent substrate concentration (60-120 Cmmol VFA/L) and HRT ratio between the reactors (0.2-0.5h/h) on the system's selection efficiency was assessed. It was shown that Feast reactor residual substrate concentration impacted on the selective pressure for PHA storage (due to substrate-dependent kinetic limitation). Moreover, a residual substrate concentration coming from the Feast to the Famine reactor did not jeopardize the physiological adaptation required for enhanced PHA storage. The culture reached a maximum PHA content of 61%. This success opens new perspectives to the use of wastewater treatment infrastructure for PHA production, thus valorizing either excess sludge or wastewaters. Copyright 2010 Elsevier Ltd. All rights reserved.

Enrichment and activity of methanotrophic microorganisms from municipal wastewater sludge.

PubMed

Siniscalchi, Luciene Alves Batista; Vale, Isabel Campante; Dell'Isola, Jéssica; Chernicharo, Carlos Augusto; Calabria Araujo, Juliana

2015-01-01

In this study, methanotrophic microorganisms were enriched from a municipal wastewater sludge taken from an Upflow Anaerobic Sludge Blanket reactor. The enrichment was performed in a sequencing batch reactor (SBR) with an autotrophic medium containing nitrite and nitrate. The microbial community composition of the inoculum and of the enrichment culture after 100 days of SBR operation was investigated and compared with the help of data obtained from 454 pyrosequencing analyses. The nitrite and nitrate removal efficiencies were 68% and 53%, respectively, probably due to heterotrophic denitrification. Archaeal cells of the anaerobic methanotrophic Archaic (ANME)-I and ANME-II groups were detected by polymerase chain reaction throughout the whole cultivation period. Pyrosequencing analysis showed that community composition was different among the two samples analysed. The dominant phyla found in the inoculum were Synergistestes, Firmicutes and Euryarchaeota, while Planctomycetes, Verrucomicrobia, Chloroflexi and Proteobacteria prevailed in the enriched biomass. The cultivation conditions decreased Methanobacterium abundance from 8% to 1%, and enriched for methanotrophic bacteria such as Methylocaldum, Methylocistis and Methylosinus. Sequences of Methylocaldum sp. accounted for 2.5% of the total reads. The presence and high predominance of Verrucomicrobia in the enriched biomass suggested that other unknown methanotrophic species related to that phylum might also have occurred in the reactor. Anaerobic methane oxidation activity was measured for both samples, and showed that the activity of the enrichment culture was nearly three times higher than the activity of the inoculum. Taken together, these results showed that the inoculum type and cultivation conditions were properly suited for methanotrophic enrichment.

Characteristics of N2O production and hydroxylamine variation in short-cut nitrification SBR process.

PubMed

Hu, Bo; Ye, Junhong; Zhao, Jianqiang; Ding, Xiaoqian; Yang, Liwei; Tian, Xiaolei

2018-01-01

In order to study the characteristics of nitrous oxide (N 2 O) production and hydroxylamine (NH 2 OH) variation under oxic conditions, concentrations of NH 2 OH and N 2 O were simultaneously monitored in a short-cut nitrification sequencing batch reactor (SBR) operated with different influent ammonia concentrations. In the short-cut nitrification process, N 2 O production was increased with the increasing of ammonia concentration in influent. The maximum concentrations of dissolved N 2 O-N in the reactor were 0.11 mg/L and 0.52 mg/L when ammonia concentrations in the influent were 50 mg/L and 70 mg/L respectively. Under the low and medium ammonia load phases, the concentrations of NH 2 OH-N in the reactor were remained at a low level which fluctuated around 0.06 mg/L in a small range, and did not change with the variation of influent NH 4 + -N concentration. Based on the determination results, the half-saturation of NH 2 OH in the biochemical conversion process of NH 2 OH to NO 2 - -N was very small, and the value of 0.05 mg NH 2 OH-N/L proposed in the published literature was accurate. NH 2 OH is an important intermediate in the nitrification process, and the direct determination of NH 2 OH in the nitrification process was beneficial for revealing the kinetic process of NH 2 OH production and consumption as well as the effects of NH 2 OH on N 2 O production in the nitrification process.

Impact of nitrogen feeding regulation on polyhydroxyalkanoates production by mixed microbial cultures.

PubMed

Silva, Fernando; Campanari, Sabrina; Matteo, Stefania; Valentino, Francesco; Majone, Mauro; Villano, Marianna

2017-07-25

A sequencing batch reactor (SBR) is typically used for selecting mixed microbial cultures (MMC) for polyhydroxyalkanoate (PHA) production. Since many waste streams suitable as process feedstock for PHA production are nitrogen-deficient, a nutrient supply in the SBR is typically required to allow for efficient microbial growth. The scope of this study was to devise a nitrogen feeding strategy which allows controlling the nitrogen levels during the feast and famine regime of a lab-scale SBR, thereby selecting for PHA-storing microorganisms. At the beginning of the cycle the reactor was fed with a synthetic mixture of acetic and propionic acids at an overall organic load rate of 8.5gCODL -1 d -1 (i.e. 260CmmolL -1 d -1 ), whereas nitrogen (in the form of ammonium sulphate) was added either simultaneously to the carbon feed (coupled feeding strategy) or after the end of the feast phase (uncoupled feeding strategy). As a main result, PHA production was more than doubled (up to about 1300±64mgCODL -1 ) when carbon and nitrogen were separately fed and the higher PHA production also corresponded to an 82% increase in the polymer HV content (up to 20±1%, wtwt -1 ). Three SBR runs were performed with the uncoupled carbon and nitrogen feeding at different carbon to nitrogen (C/N) ratios (of 14.3, 17.9, and 22.3CmolNmol -1 , respectively) which were varied by progressively reducing the concentration of the nitrogen feeding. In spite of a comparable PHA storage yield at 14.3 and 17.9CmolNmol -1 (0.41±0.05 gCOD PHA gCOD VFA -1 and 0.38±0.05 gCOD PHA gCOD VFA -1 , respectively), the storage response of the selected MMC significantly decreased when the C/N ratio was set at the highest investigated value. Notably, an increase in this parameter also resulted in a change in the HV content in the polymer regardless the composition of the organic acids solution. Copyright © 2016 Elsevier B.V. All rights reserved.

Perspectives on anaerobic treatment in developing countries.

PubMed

Foresti, E

2001-01-01

Developing countries occupy regions where the climate is warm most of the time. Even in sub-tropical areas, low temperatures do not persist for long periods. This is the main factor that makes the use of anaerobic technology applicable and less expensive, even for the treatment of low-strength industrial wastewaters and domestic sewage. Based mainly on papers presented at the "VI Latin-American Workshop and Seminar on Anaerobic Digestion" held in Recife, Brazil, in November 2000, this text approaches the perspectives of anaerobic treatment of wastewaters in developing countries. Emphasis is given to domestic sewage treatment and to the use of compact systems in which sequential batch reactors (SBR) or dissolvedair flotation (DAF) systems are applied for the post-treatment of anaerobic reactor effluents. Experiments on bench- and pilot-plants have indicated that these systems can achieve high performance in removing organic matter and nutrients during the treatment of domestic sewage at ambient temperatures.

Aerobic dynamic feeding as a strategy for in situ accumulation of polyhydroxyalkanoate in aerobic granules.

PubMed

Gobi, K; Vadivelu, V M

2014-06-01

Aerobic dynamic feeding (ADF) strategy was applied in sequencing batch reactor (SBR) to accumulate polyhydroxyalkanoate (PHA) in aerobic granules. The aerobic granules were able to remove 90% of the COD from palm oil mill effluent (POME). The volatile fatty acids (VFAs) in the POME are the sole source of the PHA accumulation. In this work, 100% removal of propionic and butyric acids in the POME were observed. The highest amount of PHA produced in aerobic granules was 0.6833mgPHA/mgbiomass. The PHA formed was identified as a P (hydroxybutyrate-co-hydroxyvalerate) P (HB-co-HV). Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of Sludge Retention Times on Nutrient Removal and Nitrous Oxide Emission in Biological Nutrient Removal Processes

PubMed Central

Li, Bo; Wu, Guangxue

2014-01-01

Sludge retention time (SRT) is an important factor affecting not only the performance of the nutrient removal and sludge characteristics, but also the production of secondary pollutants such as nitrous oxide (N2O) in biological nutrient removal (BNR) processes. Four laboratory-scale sequencing batch reactors (SBRs), namely, SBR5, SBR10, SBR20 and SBR40 with the SRT of 5 d, 10 d, 20 d and 40 d, respectively, were operated to examine effects of SRT on nutrient removal, activated sludge characteristics and N2O emissions. The removal of chemical oxygen demand or total phosphorus was similar under SRTs of 5–40 d, SRT mainly affected the nitrogen removal and the optimal SRT for BNR was 20 d. The molecular weight distribution of the effluent organic matters was in the range of 500–3,000 Da under SRTs of 5–40 d. The lowest concentration of the effluent soluble microbial products concentration was obtained at the SRT of 5 d. Nitrifier growth was limited at a short SRT and nitrite existed in the effluent of SBR5. With increasing SRTs, mixed liquor suspended solids concentration increased while the excess sludge production was reduced due to the high endogenous decay rate at high SRTs. Endogenous decay coefficients were 0.020 d−1, 0.036 d−1, 0.037 d−1 and 0.039 d−1 under SRTs of 5–40 d, respectively. In BNR, the N2O emission occurred mainly during the aerobic phase and its emission ratio decreased with increasing SRTs. The ratio between the N2O-N emission and the removed ammonium nitrogen in the aerobic phase was 5%, 3%, 1.8% and 0.8% at the SRT of 5 d, 10 d, 20 d and 40 d, respectively. With low concentrations of dissolved oxygen and high concentrations of oxidized nitrogen, the N2O emission was significantly accelerated due to heterotrophic denitrification activities. PMID:24681555

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

Nitritating-anammox biomass tolerant to high dissolved oxygen concentration and C/N ratio in treatment of yeast factory wastewater.

PubMed

Zekker, Ivar; Rikmann, Ergo; Tenno, Toomas; Seiman, Andrus; Loorits, Liis; Kroon, Kristel; Tomingas, Martin; Vabamäe, Priit; Tenno, Taavo

2014-01-01

Maintaining stability of low concentration (< 1 g L(-1)) floccular biomass in the nitritation-anaerobic ammonium oxidation (anammox) process in the sequencing batch reactor (SBR) system for the treatment of high COD (> 15,000 mg O2 L(-1)) to N (1680 mg N L(-1)) ratio real wastewater streams coming from the food industry is challenging. The anammox process was suitable for the treatment of yeast factory wastewater containing relatively high and abruptly increased organic C/N ratio and dissolved oxygen (DO) concentrations. Maximum specific total inorganic nitrogen (TIN) loading and removal rates applied were 600 and 280 mg N g(-1) VSS d(-1), respectively. Average TIN removal efficiency over the operation period of 270 days was 70%. Prior to simultaneous reduction of high organics (total organic carbon > 600mg L(-1)) and N concentrations > 400 mg L(-1), hydraulic retention time of 15 h and DO concentrations of 3.18 (+/- 1.73) mg O2 L(-1) were applied. Surprisingly, higher DO concentrations did not inhibit the anammox process efficiency demonstrating a wider application of cultivated anammox biomass. The SBR was fed rapidly over 5% of the cycle time at 50% volumetric exchange ratio. It maintained high free ammonia concentration, suppressing growth of nitrite-oxidizing bacteria. Partial least squares and response surface modelling revealed two periods of SBR operation and the SBR performances change at different periods with different total nitrogen (TN) loadings. Anammox activity tests showed yeast factory-specific organic N compound-betaine and inorganic N simultaneous biodegradation. Among other microorganisms determined by pyrosequencing, anammox microorganism (uncultured Planctomycetales bacterium clone P4) was determined by polymerase chain reaction also after applying high TN loading rates.

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.

Influence of temperature, pH and dissolved oxygen concentration on enhanced biological phosphorus removal under strictly aerobic conditions.

PubMed

Nittami, Tadashi; Oi, Hiroshi; Matsumoto, Kanji; Seviour, Robert J

2011-12-15

Previous research has suggested that enhanced biological phosphorus removal (EBPR) from wastewater can be achieved under continuous aerobic conditions over the short term. However, little is known how environmental conditions might affect aerobic EBPR performance. Consequently we have investigated the impact of temperature, pH and dissolved oxygen (DO) concentrations on EBPR performance under strictly aerobic conditions. A sequencing batch reactor (SBR) was operated for 108 days on a six-hour cycle (four cycles a day). The SBR ran under alternating anaerobic-aerobic conditions as standard and then operated under strictly aerobic conditions for one cycle every three or four days. SBR operational temperature (10, 15, 20, 25 and 30°C), pH (6, 7, 8 and 9) and DO concentration (0.5, 2.0 and 3.5mg/L) were changed consecutively during the aerobic cycle. Recorded increases in mixed liquor phosphorus (P) concentrations during aerobic carbon source uptake (P release) were affected by the biomass P content rather than the imposed changes in the operational conditions. Thus, P release levels increased with biomass P content. By contrast, subsequent aerobic P assimilation (P uptake) levels were both affected by changes in operational temperature and pH, and peaked at 20-25°C and pH 7-8. Highest P uptake detected under these SBR operating conditions was 15.4 mg Pg-MLSS(-1) (at 25°C, pH 7 and DO 2.0mg/L). The ability of the community for linked aerobic P release and P uptake required the presence of acetate in the medium, a finding which differs from previous data, where these are reported to occur in the absence of any exogenous carbon source. Fluorescence in situ hybridization was performed on samples collected from the SBR, and Candidatus 'Accumulibacter phosphatis' cells were detected with PAOmix probes through the operational periods. Thus, Candidatus 'Accumulibacter phosphatis' seemed to perform P removal in the SBR as shown in previous studies on P removal under strictly aerobic conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

The stability of accumulating nitrite from Swine wastewater in a sequencing batch reactor.

PubMed

Wang, Liang; Zhu, Jun; Miller, Curtis

2011-02-01

Shortcut nitrification is the first step of shortcut nitrogen removal from swine wastewater. Stably obtaining an effluent with a significant amount of nitrite is the premise for the subsequent shortcut denitrification. In this paper, the stability of nitrite accumulation was investigated using a 1.5-day hydraulic retention time in a 10-L (working volume) activated sludge sequencing batch reactor (SBR) with an 8-h cycle consisted of 4 h 38 min aerobic feeding, 1 h 22 min aerobic reaction, 30 min settling, 24 min withdrawal, and 1 h 6 min idle. The nitrite production stability was tested using four different ammonium loading rates, 0.075, 0.062, 0.053, and 0.039 g NH(4)-N/g (mixed liquid suspended solid, MLSS) day in a 2-month running period. The total inorganic nitrogen composition in the effluent was not affected when the ammonium load was between 0.053 and 0.075 g NH(4)-N/g MLSS · day (64% NO(2)-N, 16% NO(3)-N, and 20% NH(4)-N). Under 0.039 g NH(4)-N/g MLSS · day, more NO(2)-N was transformed to NO(3)-N with an effluent of 60% NO(2)-N, 20% NO(3)-N, and 20% NH(4)-N. The reducing load test was able to show the relationship between a declining free nitrous acid (FNA) concentration and the decreasing nitrite production, indicating that the inhibition of FNA on nitrite oxidizing bacteria depends on its levels and an ammonium loading rate around 0.035 g NH(4)-N/g MLSS · day is the lower threshold for producing a nitrite dominance effluent in the activated sludge SBR under the current settings.

Predicting the degradability of waste activated sludge.

PubMed

Jones, Richard; Parker, Wayne; Zhu, Henry; Houweling, Dwight; Murthy, Sudhir

2009-08-01

The objective of this study was to identify methods for estimating anaerobic digestibility of waste activated sludge (WAS). The WAS streams were generated in three sequencing batch reactors (SBRs) treating municipal wastewater. The wastewater and WAS properties were initially determined through simulation of SBR operation with BioWin (EnviroSim Associates Ltd., Flamborough, Ontario, Canada). Samples of WAS from the SBRs were subsequently characterized through respirometry and batch anaerobic digestion. Respirometry was an effective tool for characterizing the active fraction of WAS and could be a suitable technique for determining sludge composition for input to anaerobic models. Anaerobic digestion of the WAS revealed decreasing methane production and lower chemical oxygen demand removals as the SRT of the sludge increased. BioWin was capable of accurately describing the digestion of the WAS samples for typical digester SRTs. For extended digestion times (i.e., greater than 30 days), some degradation of the endogenous decay products was assumed to achieve accurate simulations for all sludge SRTs.

Biochemical pathways and enhanced degradation of di-n-octyl phthalate (DOP) in sequencing batch reactor (SBR) by Arthrobacter sp. SLG-4 and Rhodococcus sp. SLG-6 isolated from activated sludge.

PubMed

Zhang, Ke; Liu, Yihao; Chen, Qiang; Luo, Hongbing; Zhu, Zhanyuan; Chen, Wei; Chen, Jia; Mo, You

2018-04-01

Two bacterial strains designated as Arthrobacter sp. SLG-4 and Rhodococcus sp. SLG-6, capable of utilizing di-n-octyl phthalate (DOP) as sole source of carbon and energy, were isolated from activated sludge. The analysis of DOP degradation intermediates indicated Arthrobacter sp. SLG-4 could completely degrade DOP. Whereas DOP could not be mineralized by Rhodococcus sp. SLG-6 and the final metabolic product was phthalic acid (PA). The proposed DOP degradation pathway by Arthrobacter sp. SLG-4 was that strain SLG-4 initially transformed DOP to PA via de-esterification pathway, and then PA was metabolized to protocatechuate acid and eventually converted to tricarboxylic acid (TCA) cycle through meta-cleavage pathway. Accordingly, Phthalate 3,4-dioxygenase genes (phtA) responsible for PA degradation were successfully detected in Arthrobacter sp. SLG-4 by real-time quantitative PCR (q-PCR). q-PCR analysis demonstrated that the quantity of phthalate 3,4-dioxygenase was positively correlated to DOP degradation in SBRs. Bioaugmentation by inoculating DOP-degrading bacteria effectively shortened the start-up of SBRs and significantly enhanced DOP degradation in bioreactors. More than 91% of DOP (500 mg L -1 ) was removed in SBR bioaugmented with bacterial consortium, which was double of the control SBR. This study suggests bioaugmentation is an effective and feasible technique for DOP bioremediation in practical engineering.

Thermolysis of scrap tire and rubber in sub/super-critical water.

PubMed

Li, Qinghai; Li, Fuxin; Meng, Aihong; Tan, Zhongchao; Zhang, Yanguo

2018-01-01

The rapid growth of waste tires has become a serious environmental issue. Energy and material recovery is regarded as a promising use for waste tires. Thermolysis of scrap tire (ST), natural rubber (NR), and styrene-butadiene rubber (SBR) was carried out in subcritical and supercritical water using a temperature-pressure independent adjustable batch tubular reactor. As a result, oil yields increased as temperature and pressure increased, and they reached maximum values as the state of water was near the critical point. However, further increases in water temperature and pressure reduced the oil yields. The maximum oil yield of 21.21% was obtained at 420 °C and 18 MPa with a reaction time of 40 min. The relative molecular weights of the chemicals in the oil products were in the range of 70-140 g/mole. The oil produced from ST, NR, and SBR contained similar chemical compounds, but the oil yield of SR was between those of NR and SBR. The oil yield from thermolysis of subcritical or supercritical water should be further improved. The main gaseous products, including CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , and C 3 H 8 , increased with reaction time, temperature, and pressure, whereas the solid residues, including carbon black and impurities, decreased. These results provide useful information to develop a sub/super-critical water thermolysis process for energy and material regeneration from waste tires. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improvement of the trace metal composition of medium for nitrite-dependent anaerobic methane oxidation bacteria: Iron (II) and copper (II) make a difference.

PubMed

He, Zhanfei; Geng, Sha; Pan, Yawei; Cai, Chaoyang; Wang, Jiaqi; Wang, Liqiao; Liu, Shuai; Zheng, Ping; Xu, Xinhua; Hu, Baolan

2015-11-15

Nitrite-dependent anaerobic methane oxidation (n-damo) is a potential bioprocess for treating nitrogen-containing wastewater. This process uses methane, an inexpensive and nontoxic end-product of anaerobic digestion, as an external electron donor. However, the low turnover rate and slow growth rate of n-damo functional bacteria limit the practical application of this process. In the present study, the short- and long-term effects of variations in trace metal concentrations on n-damo bacteria were investigated, and the concentrations of trace metal elements of medium were improved. The results were subsequently verified by a group of long-term inoculations (90 days) and were applied in a sequencing batch reactor (SBR) (84 days). The results indicated that iron (Fe(II)) and copper (Cu(II)) (20 and 10 μmol L(-1), respectively) significantly stimulated the activity and the growth of n-damo bacteria, whereas other trace metal elements, including zinc (Zn), molybdenum (Mo), cobalt (Co), manganese (Mn), and nickel (Ni), had no significant effect on n-damo bacteria in the tested concentration ranges. Interestingly, fluorescence in situ hybridization (FISH) showed that a large number of dense, large aggregates (10-50 μm) of n-damo bacteria were formed by cell adhesion in the SBR reactor after using the improved medium, and to our knowledge this is the first discovery of large aggregates of n-damo bacteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of ozonation and biodegradation on toxicity of industrial textile wastewater.

PubMed

Paździor, Katarzyna; Wrębiak, Julita; Klepacz-Smółka, Anna; Gmurek, Marta; Bilińska, Lucyna; Kos, Lech; Sójka-Ledakowicz, Jadwiga; Ledakowicz, Stanisław

2017-06-15

The textile industry demands huge volumes of high quality water which converts into wastewater contaminated by wide spectrum of chemicals. Estimation of textile wastewater influence on the aquatic systems is a very important issue. Therefore, closing of the water cycle within the factories is a promising method of decreasing its environmental impact as well as operational costs. Taking both reasons into account, the aim of this work was to establish the acute toxicity of the textile wastewater before and after separate chemical, biological as well as combined chemical-biological treatment. For the first time the effects of three different combinations of chemical and biological methods were investigated. The acute toxicity analysis were evaluated using the Microtox ® toxicity test. Ozonation in two reactors of working volume 1 dm 3 (stirred cell) and 20 dm 3 (bubble column) were tested as chemical process, while biodegradation was conducted in two, different systems - Sequence Batch Reactors (SBR; working volume 1.5 dm 3 ) and Horizontal Continuous Flow Bioreactor (HCFB; working volume 12 dm 3 ). The untreated wastewater had the highest toxicity (EC50 value in range: 3-6%). Ozonation caused lower reduction of the toxicity than biodegradation. In the system with SBR the best results were obtained for the biodegradation followed by the ozonation and additional biodegradation - 96% of the toxicity removal. In the second system (with HCFB) two-stage treatment (biodegradation followed by the ozonation) led to the highest toxicity reduction (98%). Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2017-01-01

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

Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

NASA Astrophysics Data System (ADS)

Mat Saad, Azlina; Aini Dahalan, Farrah; Ibrahim, Naimah; Yasina Yusuf, Sara; Aqlima Ahmad, Siti; Khalil, Khalilah Abdul

2018-03-01

Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic - anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

Using nuclear microscopy to characterize the interaction of textile-used silver nanoparticles with a biological wastewater treatment system

NASA Astrophysics Data System (ADS)

Bento, J. B.; Franca, R. D. G.; Pinheiro, T.; Alves, L. C.; Pinheiro, H. M.; Lourenço, N. D.

2017-08-01

The use of engineered nanoparticles in the textile industry has been rapidly increasing but their fate during biological wastewater treatment is largely unknown. The goal of the current study was to characterize the interaction of silver nanoparticles (AgNPs), used in the textile industry, with a biological wastewater treatment system based on aerobic granular sludge (AGS). The exposure tests were performed using a laboratory-scale sequencing batch reactor (SBR) system with AGS. The behavior and fate of textile AgNPs in the AGS system was studied with nuclear microscopy techniques. Elemental maps of AGS samples collected from the SBR showed that AgNPs typically clustered in agglomerates of small dimensions (<10 μm), which were preferentially associated with extracellular polymeric substances (EPS). This preliminary study highlights the potential application of nuclear microscopy for the characterization of the behavior and fate of AgNPs in AGS. The detailed compartmentalization of AgNPs in AGS components obtained with nuclear microscopy provides new and relevant information concerning AgNPs retention. This will be important in biotechnological terms to delineate strategies for AgNPs removal from textile wastewater.

Structure-biodegradability relationship of nonylphenol isomers during biological wastewater treatment process.

PubMed

Hao, Ruixia; Li, Jianbing; Zhou, Yuwen; Cheng, Shuiyuan; Zhang, Yi

2009-05-01

The relationship between nonylphenol (NP) isomer structure and its biodegradability within the wastewater treatment process of sequencing batch reactor (SBR) was investigated. The GC-MS method was used for detecting the NP isomers existing in the SBR influent, activated sludge and effluent. Fifteen NP isomers were detected in the influent, with significant biodegradability variations being observed among these isomers. It was found that the NP isomers associated with retention time of 10.553, 10.646, 10.774, and 10.906 min in the GC-MS analysis showed higher biodegradability, while the isomers with retention time of 10.475, 10.800, and 10.857 min illustrated lower biodegradability. Through analyzing the mass spectrograms, the chemical structures of four selected NP isomers in the wastewater were further deduced. The higher correlation coefficients of 0.9421 and 0.9085 were observed between the NP isomer biodegradation rates and the molecular connectivity indexes with the order of two and four, respectively. Such correlation analysis indicated that a more complex side branch structure (such as a larger side carbon-chain branch or more branches in the nonyl) of NP isomer would lead to lower biodegradability, and a longer nonyl chain of the isomer would result in a higher biodegradability.

Effect of TiO2 nanoparticles on aerobic granulation of algal-bacterial symbiosis system and nutrients removal from synthetic wastewater.

PubMed

Li, Bing; Huang, Wenli; Zhang, Chao; Feng, Sisi; Zhang, Zhenya; Lei, Zhongfang; Sugiura, Norio

2015-01-01

The influence of TiO2 nanoparticles (TiO2-NPs) (10-50mg/L) on aerobic granulation of algal-bacterial symbiosis system was investigated by using two identical sequencing batch reactors (SBRs). Although little adverse effect was observed on their nitritation efficiency (98-100% in both reactors), algal-bacterial granules in the control SBR (Rc) gradually lost stability mainly brought about by algae growth. TiO2-NPs addition to RT was found to enhance the granulation process achieving stable and compact algal-bacterial granules with remarkably improved nitratation thus little nitrite accumulation in RT when influent TiO2-NPs⩾30mg/L. Despite almost similar organics and phosphorus removals obtained in both reactors, the stably high nitratation efficiency in addition to much stable granular structure in RT suggests that TiO2-NPs addition might be a promising remedy for the long-term operation of algal-bacterial granular system, most probably attributable to the stimulated excretion of extracellular polymeric substances and less filamentous TM7. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of fermented wastewaters from butter production on phosphates removal in a sequencing batch reactor.

PubMed

Janczukowicz, Wojciech; Rodziewicz, Joanna; Thornton, Arthur; Czaplicka, Kamila

2012-09-01

This study determined the potential for fermented wastewaters from butter production plant to act as a carbon source to facilitate phosphates removal. Synthetic dairy wastewaters were treated using SBR, with doses of fermented wastewaters. An increase in the fermented wastewater doses were found to improve the effluent quality in respect of phosphates and nitrates. The lowest concentrations of phosphate and nitrates, respectively 0.10 ± 0.04 mg PO(4)-PL(-1) and 1.03 ± 0.22 mg NO(3)-NL(-1), were noted in the effluent from the reactor fed with fermented wastewaters in a dose of 0.25 L d(-1) per 0.45 L d(-1) of wastewaters fed to the reactor. In the case of the two highest doses, an increase in effluent COD was stated. The higher effectiveness resulted from the fact that the introduction of fermented wastewaters caused an increase in the easily-available carbon compounds content and the predominance of acetic acid amongst VFAs available to dephosphatating and denitrifying bacteria. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of salinity on extracellular polymeric substances of activated sludge from an anoxic-aerobic sequencing batch reactor.

PubMed

Wang, Zichao; Gao, Mengchun; Wang, Zhe; She, Zonglian; Chang, Qingbo; Sun, Changqing; Zhang, Jian; Ren, Yun; Yang, Ning

2013-11-01

The effect of salinity on extracellular polymeric substances (EPS) of activated sludge was investigated in an anoxic-aerobic sequencing batch reactor (SBR). The contents of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) were positively correlated with the salinity. The polysaccharide (PS) and protein (PN) contents in both LB-EPS and TB-EPS increased with the increase of salinity. With the increase of salinity from 0.5% to 6%, the PN/PS ratios in LB-EPS and TB-EPS decreased from 4.8 to 0.9 and from 2.9 to 1.4, respectively. The four fluorescence peaks in both LB-EPS and TB-EPS identified by three-dimensional excitation-emission matrix fluorescence spectroscopy are attributed to PN-like substances and humic acid-like substances. The Fourier transform infrared spectra of the LB-EPS and TB-EPS appeared to be very similar, but the differences across the spectra were apparent in terms of the relative intensity of some bands with the increase of salinity. The sludge volume index showed a linear correlation with LB-EPS (R(2)=0.9479) and TB-EPS (R(2)=0.9355) at different salinities, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Alternative solutions for the bio-denitrification of landfill leachates using pine bark and compost.

PubMed

Trois, Cristina; Pisano, Giulia; Oxarango, Laurent

2010-06-15

Nitrified leachate may still require an additional bio-denitrification step, which occurs with the addition of often-expensive chemicals as carbon source. This study explores the applicability of low-cost carbon sources such as garden refuse compost and pine bark for the denitrification of high strength landfill leachates. The overall objective is to assess efficiency, kinetics and performance of the substrates in the removal of high nitrate concentrations. Garden refuse and pine bark are currently disposed of in general waste landfills in South Africa, separated from the main waste stream. A secondary objective is to assess the feasibility of re-using green waste as by-product of an integrated waste management system. Denitrification processes in fixed bed reactors were simulated at laboratory scale using anaerobic batch tests and leaching columns packed with immature compost and pine bark. Biologically treated leachate from a Sequencing Batch Reactor (SBR) with nitrate concentrations of 350, 700 and 1100 mgN/l were used for the trials. Preliminary results suggest that, passed the acclimatization step (40 days for both substrates), full denitrification is achieved in 10-20 days for the pine bark and 30-40 days for the compost. Copyright 2010 Elsevier B.V. All rights reserved.

Auto-aggregation properties of a novel aerobic denitrifier Enterobacter sp. strain FL.

PubMed

Wang, Xia; An, Qiang; Zhao, Bin; Guo, Jin Song; Huang, Yuan Sheng; Tian, Meng

2018-02-01

Enterobacter sp. strain FL was newly isolated from activated sludge and exhibited significant capability of auto-aggregation as well as aerobic denitrification. The removal efficiencies of NO 3 - -N, total nitrogen (TN), and TOC by strain FL in batch culture reached 94.6, 63.9, and 72.5% in 24 h, respectively. The production of N 2 O and N 2 in the presence of oxygen demonstrated the occurrence of aerobic denitrification. The auto-aggregation index of strain FL reached 54.3%, suggesting a high tendency that the cells would agglomerate into aggregates. The production of extracellular polymeric substances (EPSs), which were mainly composed of proteins followed by polysaccharides, was considered to be related to the cell aggregation according to Fourier transform infrared (FT-IR) and confocal laser scanning microscopy (CLSM). The proteins in EPS were evenly and tightly combined to cells and altered the protein secondary structures of cell surface from random coils to β-sheets and three-turn helices. The alteration of protein secondary structures of cell surface caused by the proteins in EPS might play a dominant role in the auto-aggregation of strain FL. To further assess the feasibility of strain FL for synthetic wastewater treatment, a sequencing batch reactor (SBR), solely inoculated with strain FL, was conducted. During the 16 running cycles, the removal efficiency of NO 3 - -N was 90.2-99.7% and the auto-aggregation index was stabilized at 35.0-41.5%. The EPS promoted the biomass of strain FL to aggregate in the SBR.

Removal of antibiotics in wastewater: Effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process.

PubMed

Kim, Sungpyo; Eichhorn, Peter; Jensen, James N; Weber, A Scott; Aga, Diana S

2005-08-01

A study was conducted to examine the influence of hydraulic retention time (HRT) and solid retention time (SRT) on the removal of tetracycline in the activated sludge processes. Two lab-scale sequencing batch reactors (SBRs) were operated to simulate the activated sludge process. One SBR was spiked with 250 microg/L tetracycline, while the other SBR was evaluated at tetracycline concentrations found in the influent of the wastewater treatment plant (WWTP) where the activated sludge was obtained. The concentrations of tetracyclines in the influent of the WWTP ranged from 0.1 to 0.6 microg/L. Three different operating conditions were applied during the study (phase 1-HRT: 24 h and SRT: 10 days; phase 2-HRT: 7.4 h and SRT: 10 days; and phase 3-HRT: 7.4 h and SRT: 3 days). The removal efficiency of tetracycline in phase 3 (78.4 +/- 7.1%) was significantly lower than that observed in phase 1 (86.4 +/- 8.7%) and phase 2 (85.1 +/- 5.4%) at the 95% confidence level. The reduction of SRT in phase 3 while maintaining a constant HRT decreased tetracycline removal efficiency. Sorption kinetics reached equilibrium within 24 h. Batch equilibrium experiments yielded an adsorption coefficient (Kads) of 8400 +/- 500 mL/g and a desorption coefficient (Kdes) of 22 600 +/- 2200 mL/g. No evidence of biodegradation for tetracycline was observed during the biodegradability test, and sorption was found to be the principal removal mechanism of tetracycline in activated sludge.

Investigation of decolorization of textile wastewater in an anaerobic/aerobic biological activated carbon system (A/A BAC).

PubMed

Pasukphun, N; Vinitnantharat, S; Gheewala, S

2010-04-01

The aim of this study is to investigate the decolorization in anaerobic/aerobic biological activated carbon (A/A BAC) system. The experiment was divided into 2 stages; stage I is batch test for preliminary study of dye removal equilibrium time. The preliminary experiment (stage I) provided the optimal data for experimental design of A/A BAC system in SBR (stage II). Stage II is A/A BAC system imitated Sequencing Batch Reactor (SBR) which consist of 5 main periods; fill, react, settle, draw and idle. React period include anaerobic phase followed by aerobic phase. The BAC main media; Granular Activated Carbon (GAC), Mixed Cultures (MC) and Biological Activated Carbon (BAC) were used for dye and organic substances removal in three different solutions; Desizing Agent Solution (DAS), dye Solution (DS) and Synthetic Textile Wastewater (STW). Results indicate that GAC adsorption plays role in dye removal followed by BAC and MC activities, respectively. In the presence desizing agent, decolorization by MC was improved because desizing agent acts as co-substrates for microorganisms. It was found that 50% of dye removal efficiency was achieved in Fill period by MC. GC/MS analysis was used to identify dye intermediate from decolorization. Dye intermediate containing amine group was found in the solution and on BAC surfaces. The results demonstrated that combination of MC and BAC in the system promotes decolorization and dye intermediate removal. In order to improve dye removal efficiency in an A/A BAC system, replacement of virgin GAC, sufficient co-substrates supply and the appropriate anaerobic: aerobic period should be considered.

Comparison of batch and column tests for the elution of artificial turf system components.

PubMed

Krüger, O; Kalbe, U; Berger, W; Nordhauβ, K; Christoph, G; Walzel, H-P

2012-12-18

Synthetic athletic tracks and turf areas for outdoor sporting grounds may release contaminants due to the chemical composition of some components. A primary example is that of zinc from reused scrap tires (main constituent, styrene butadiene rubber, SBR), which might be harmful to the environment. Thus, methods for the risk assessment of those materials are required. Laboratory leaching methods like batch and column tests are widely used to examine the soil-groundwater pathway. We tested several components for artificial sporting grounds with batch tests at a liquid to solid (LS) ratio of 2 L/kg and column tests with an LS up to 26.5 L/kg. We found a higher zinc release in the batch test eluates for all granules, ranging from 15% higher to 687% higher versus data from column tests for SBR granules. Accompanying parameters, especially the very high turbidity of one ethylene propylene diene monomer rubber (EPDM) or thermoplastic elastomer (TPE) eluates, reflect the stronger mechanical stress of batch testing. This indicates that batch test procedures might not be suitable for the risk assessment of synthetic sporting ground components. Column tests, on the other hand, represent field conditions more closely and allow for determination of time-dependent contaminants release.

Anaerobic co-digestion of Tunisian green macroalgae Ulva rigida with sugar industry wastewater for biogas and methane production enhancement.

PubMed

Karray, Raida; Karray, Fatma; Loukil, Slim; Mhiri, Najla; Sayadi, Sami

2017-03-01

Ulva rigida is a green macroalgae, abundantly available in the Mediterranean which offers a promising source for the production of valuable biomaterials, including methane. In this study, anaerobic digestion assays in a batch mode was performed to investigate the effects of various inocula as a mixture of fresh algae, bacteria, fungi and sediment collected from the coast of Sfax, on biogas production from Ulva rigida. The results revealed that the best inoculum to produce biogas and feed an anaerobic reactor is obtained through mixing decomposed macroalgae with anaerobic sludge and water, yielding into 408mL of biogas. The process was then investigated in a sequencing batch reactor (SBR) which led to an overall biogas production of 375mL with 40% of methane. Further co-digestion studies were performed in an anaerobic up-flow bioreactor using sugar wastewater as a co-substrate. A high biogas production yield of 114mL g -1 VS added was obtained with 75% of methane. The co-digestion proposed in this work allowed the recovery of natural methane, providing a promising alternative to conventional anaerobic microbial fermentation using Tunisian green macroalgae. Finally, in order to identify the microbial diversity present in the reactor during anaerobic digestion of Ulva rigida, the prokaryotic diversity was investigated in this bioreactor by the denaturing gradient gel electrophoresis (DGGE) method targeting the 16S rRNA gene. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodegradation of methyl t-butyl ether by aerobic granules under a cosubstrate condition.

PubMed

Zhang, L L; Chen, J M; Fang, F

2008-03-01

Aerobic granules efficient at degrading methyl tert-butyl ether (MTBE) with ethanol as a cosubstrate were successfully developed in a well-mixed sequencing batch reactor (SBR). Aerobic granules were first observed about 100 days after reactor startup. Treatment efficiency of MTBE in the reactor during stable operation exceeded 99.9%, and effluent MTBE was in the range of 15-50 microg/L. The specific MTBE degradation rate was observed to increase with increasing MTBE initial concentration from 25 to 500 mg/L, which peaked at 22.7 mg MTBE/g (volatile suspended solids).h and declined with further increases in MTBE concentration as substrate inhibition effects became significant. Microbial-community deoxyribonucleic acid profiling was carried out using denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S ribosomal ribonucleic acid. The reactor was found to be inhabited by several diverse bacterial species, most notably microorganisms related to the genera Sphingomonas, Methylobacterium, and Hyphomicrobium vulgare. These organisms were previously reported to be associated with MTBE biodegradation. A majority of the bands in the reactor represented a group of organisms belonging to the Flavobacteria-Proteobacteria-Actinobacteridae class of bacteria. This study demonstrates that MTBE can be effectively degraded by aerobic granules under a cosubstrate condition and gives insight into the microorganisms potentially involved in the process.

Microbial community analysis in a combined anaerobic and aerobic digestion system for treatment of cellulosic ethanol production wastewater.

PubMed

Shan, Lili; Yu, Yanling; Zhu, Zebing; Zhao, Wei; Wang, Haiman; Ambuchi, John J; Feng, Yujie

2015-11-01

This study investigated the microbial diversity established in a combined system composed of a continuous stirred tank reactor (CSTR), expanded granular sludge bed (EGSB) reactor, and sequencing batch reactor (SBR) for treatment of cellulosic ethanol production wastewater. Excellent wastewater treatment performance was obtained in the combined system, which showed a high chemical oxygen demand removal efficiency of 95.8% and completely eliminated most complex organics revealed by gas chromatography-mass spectrometry (GC-MS). Denaturing gradient gel electrophoresis (DGGE) analysis revealed differences in the microbial community structures of the three reactors. Further identification of the microbial populations suggested that the presence of Lactobacillus and Prevotella in CSTR played an active role in the production of volatile fatty acids (VFAs). The most diverse microorganisms with analogous distribution patterns of different layers were observed in the EGSB reactor, and bacteria affiliated with Firmicutes, Synergistetes, and Thermotogae were associated with production of acetate and carbon dioxide/hydrogen, while all acetoclastic methanogens identified belonged to Methanosaetaceae. Overall, microorganisms associated with the ability to degrade cellulose, hemicellulose, and other biomass-derived organic carbons were observed in the combined system. The results presented herein will facilitate the development of an improved cellulosic ethanol production wastewater treatment system.

Potential of low-temperature anaerobic digestion to address current environmental concerns on swine production.

PubMed

Massé, D I; Masse, L; Xia, Y; Gilbert, Y

2010-04-01

Environmental issues associated with swine production are becoming a major concern among the general public and are thus an important challenge for the swine industry. There is now a renewed interest in environmental biotechnologies that can minimize the impact of swine production and add value to livestock by-products. An anaerobic biotechnology called psychrophilic anaerobic digestion (PAD) in sequencing batch reactors (SBR) has been developed at Agriculture and Agri-Food Canada. This very stable biotechnology recovers usable energy, stabilizes and deodorizes manure, and increases the availability of plant nutrients. Experimental results indicated that PAD of swine manure slurry at 15 to 25 degrees C in intermittently fed SBR reduces the pollution potential of manure by removing up to 90% of the soluble chemical oxygen demand. The process performs well under intermittent feeding, once to 3 times a week, and without external mixing. Bioreactor feeding activities can thus be easily integrated into the routine manure removal procedures in the barn, with minimal interference with other farm operations and use of existing manure-handling equipment. Process stability was not affected by the presence of antibiotics in manure. The PAD process was efficient in eliminating populations of zoonotic pathogens and parasites present in raw livestock manure slurries. Psychrophilic anaerobic digestion in SBR could also be used for swine mortality disposal. The addition of swine carcasses, at loading rates representing up to 8 times the normal mortality rates on commercial farms, did not affect the stability of SBR. No operational problems were related to the formation of foam and scum. The biotechnology was successfully operated at semi-industrial and full commercial scales. Biogas production rate exceeded 0.20 L of methane per gram of total chemical oxygen demand fed to the SBR. The biogas was of excellent quality, with a methane concentration ranging from 70 to 80%. The recovery of green energy, the production of a value-added odorless fertilizer, the elimination of manure pathogens, and the proper disposal of swine mortalities will substantially reduce the carbon and environmental footprints on products of swine origin.

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

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

Abood, Alkhafaji R.; Thi Qar University, Nasiriyah; Bao, Jianguo, E-mail: bjianguo888@126.com

2014-02-15

Highlights: • A novel method of stripping (agitation) was investigated for NH{sub 3}-N removal. • PFS coagulation followed agitation process enhanced the leachate biodegradation. • Nitrification–denitrification achieved by changing operation process in SBR treatment. • A dual filter of carbon-sand is suitable as a polishing treatment of leachate. • Combined treatment success for the complete treatment of non-biodegradable leachate. - Abstract: 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 NH{sub 3}-N removal ratio wasmore » 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s{sup −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 (BOD{sub 5}) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L{sup −1} at pH 5.0. The biodegradable ratio BOD{sub 5}/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% BOD{sub 5}, 95.5% COD and 98.1% NH{sub 3}-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, BOD{sub 5}, suspended solid (SS), NH{sub 3}-N and total organic carbon (TOC) were 72.4 mg L{sup −1}, 22.8 mg L{sup −1}, 24.2 mg L{sup −1}, 18.4 mg L{sup −1} and 50.8 mg L{sup −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.« less

Enrichment of a mixed microbial culture for polyhydroxyalkanoates production: Effect of pH and N and P concentrations.

PubMed

Montiel-Jarillo, Gabriela; Carrera, Julián; Suárez-Ojeda, María Eugenia

2017-04-01

Polyhydroxyalkanoates (PHA) are biopolymers that can be an alternative against conventional plastics. The study reported herein evaluated the enrichment of a mixed microbial culture (MMC) operated under feast/famine regime and different pHs in a sequencing batch reactor (SBR) using acetate as sole carbon source to produce polyhydroxyalkanoates (PHAs). The enrichment step was evaluated at controlled pH of 7.5 and also without pH control (averaged value of 9.0). The acetate uptake rate (-q S ) of both enrichments at the end of the experimental period exhibited similar behaviour being about 0.18CmolAcCmolX -1 h -1 and 0.19CmolAcCmolX -1 h -1 for SBR-A and SBR-B, respectively. However, the PHA-storing capacity of the biomass enriched without pH control was better, exhibiting a maximum PHA content of 36% (gPHAg -1 VSS) with a PHA production rate (q PHA ) of 0.16CmolPHACmolX -1 h -1 . Batch experiments were performed to evaluate PHA-storing capacity of the enriched culture at different pHs and nutrients concentrations. In the pH experiments (without nutrient limitation), it was found that in the absence of controlled pH, the enriched biomass exhibited a PHA content of 44% gPHAg -1 VSS with -q S and PHA to substrate yield (Y PHA/Ac ) of 0.57CmolAcCmolX -1 h -1 and 0.33CmolPHACmolAc -1 , respectively. Regarding the experiments at variable nutrients concentration (pH ranging 8.8 to 9.2), the results indicate that the PHA content in the enriched biomass is significantly higher being around 51% gPHAg -1 VSS under nitrogen limitation. This work demonstrated the feasibility of the enrichment of a MMC with PHA storage ability without pH control. Results also suggest that better PHAs contents and substrate uptake rates are obtained without controlling the pH in the accumulation step. Finally, this work also highlights the importance of understanding the role of nutrients concentration during the accumulation step. Copyright © 2017 Elsevier B.V. All rights reserved.

Integration of Cleaner Production and Waste Water Treatment on Tofu Small Industry for Biogas Production using AnSBR Reactor

NASA Astrophysics Data System (ADS)

Rahayu, Suparni Setyowati; Budiyono; Purwanto

2018-02-01

A research on developing a system that integrates clean production and waste water treatment for biogas production in tofu small industry has been conducted. In this research, tofu waste water was turned into biogas using an AnSBR reactor. Mud from the sewage system serves as the inoculums. This research involved: (1) workshop; (2) supervising; (3) technical meeting; (4) network meeting, and (5) technical application. Implementation of clean production integrated with waste water treatment reduced the amount of waste water to be treated in a treatment plant. This means less cost for construction and operation of waste water treatment plants, as inherent limitations associated with such plants like lack of fund, limited area, and technological issues are inevitable. Implementation of clean production prior to waste water treatment reduces pollution figures down to certain levels that limitations in waste water treatment plants can be covered. Results show that biogas in 16 days HRT in an AnSBR reactor contains CH4(78.26 %) and CO2 (20.16 %). Meanwhile, treatments using a conventional bio-digester result in biogas with 72.16 % CH4 and 18.12 % CO2. Hence, biogas efficiency for the AnSBR system is 2.14 times greater than that of a conventional bio-digester.

Coupling of acrylic dyeing wastewater treatment by heterogeneous Fenton oxidation in a continuous stirred tank reactor with biological degradation in a sequential batch reactor.

PubMed

Esteves, Bruno M; Rodrigues, Carmen S D; Boaventura, Rui A R; Maldonado-Hódar, F J; Madeira, Luís M

2016-01-15

This work deals with the treatment of a recalcitrant effluent, from the dyeing stage of acrylic fibres, by combination of the heterogeneous Fenton's process in a continuous stirred tank reactor (CSTR) with biological degradation in a sequential batch reactor (SBR). Three different catalysts (a commercial Fe/ZSM-5 zeolite and two distinct Fe-containing activated carbons - ACs - prepared by wet impregnation of iron acetate and iron nitrate) were employed on the Fenton's process, and afterwards a parametric study was carried out to determine the effect of the main operating conditions, namely the hydrogen peroxide feed concentration, temperature and contact time. Under the best operating conditions found, using the activated carbon impregnated with iron nitrate, 62.7% of discolouration and 39.9% of total organic carbon (TOC) reduction were achieved, at steady-state. Furthermore, a considerable increase in the effluent's biodegradability was attained (BOD5:COD ratio increased from <0.001 to 0.27 and SOUR - specific oxygen uptake rate - from <0.2 to 11.1 mg O2/(gVSS·h)), alongside a major decrease in its toxicity (from 92.1 to 94.0% of Vibrio fischeri inhibition down to 6.9-9.9%). This allowed the application of the subsequent biological degradation stage. The combination of the two processes provided a treated effluent that clearly complies with the legislated discharge limits. It was also found that the iron leaching from the three catalysts tested was very small in all runs, a crucial factor for the stability and long-term use of such materials. Copyright © 2015 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

Nitrite survival and nitrous oxide production of denitrifying phosphorus removal sludges in long-term nitrite/nitrate-fed sequencing batch reactors.

PubMed

Wang, Yayi; Zhou, Shuai; Ye, Liu; Wang, Hong; Stephenson, Tom; Jiang, Xuxin

2014-12-15

Nitrite-based phosphorus (P) removal could be useful for innovative biological P removal systems where energy and carbon savings are a priority. However, using nitrite for denitrification may cause nitrous oxide (N2O) accumulation and emissions. A denitrifying nitrite-fed P removal system [Formula: see text] was successfully set up in a sequencing batch reactor (SBR) and was run for 210 days. The maximum pulse addition of nitrite to [Formula: see text] was 11 mg NO2(-)-N/L in the bulk, and a total of 34 mg NO2(-)-N/L of nitrite was added over three additions. Fluorescent in situ hybridization results indicated that the P-accumulating organisms (PAOs) abundance was 75 ± 1.1% in [Formula: see text] , approximately 13.6% higher than that in a parallel P removal SBR using nitrate [Formula: see text] . Type II Accumulibacter (PAOII) (unable to use nitrate as an electron acceptor) was the main PAOs species in [Formula: see text] , contributing 72% to total PAOs. Compared with [Formula: see text] , [Formula: see text] biomass had enhanced nitrite/free nitrous acid (FNA) endurance, as demonstrated by its higher nitrite denitrification and P uptake rates. N2O accumulated temporarily in [Formula: see text] after each pulse of nitrite. Peak N2O concentrations in the bulk for [Formula: see text] were generally 6-11 times higher than that in [Formula: see text] ; these accumulations were rapidly denitrified to nitrogen gases. N2O concentration increased rapidly in nitrate-cultivated biomass when 5 or 10 mg NO2(-)-N/L per pulse was added. Whereas, N2O accumulation did not occur in nitrite-cultivated biomass until up to 30 mg NO2(-)-N/L per pulse was added. Long-term acclimation to nitrite and pulse addition of nitrite in [Formula: see text] reduced the risk of nitrite accumulation, and mitigated N2O accumulation and emissions from denitrifying P removal by nitrite. Copyright © 2014 Elsevier Ltd. All rights reserved.

An integrated AMBBR and IFAS-SBR process for municipal wastewater treatment towards enhanced energy recovery, reduced energy consumption and sludge production.

PubMed

Gu, Jun; Xu, Guangjing; Liu, Yu

2017-03-01

The conventional activated sludge (CAS) process has been widely employed for wastewater treatment for more than one hundred years. Recently, more and more concerns have been raised on the CAS process due to its high energy consumption and production of huge amount of waste activated sludge, which are inevitably linked to the issue of environmental sustainability and global climate change. Facing to such emerging and challenging situation, this study reported a novel A-B process in which an anaerobic moving bed biofilm reactor (AMBBR) served a lead A-stage for COD capture towards biogas production and an integrated fixed-biofilm and activated sludge sequencing batch reactor (IFAS-SBR) was employed as B-stage for biological nitrogen removal. Results showed that about 85% of wastewater COD was removed in the steady-state AMBBR with a total energy production rate of 0.28 kWh/m 3 wastewater treated, while 85% of N-removal was achieved when the stable nitrite shunt was established in the IFAS-SBR. Moreover, 90% of dissolved methane in the AMBBR effluent could be removed by the proposed flash chamber at the lower energy demand of 0.12 kWh/m 3 which could be offset by the potential energy harvested from produced methane. Compared to the CAS process, the production of waste sludge was reduced by about 75% in the proposed A-B process due to the efficient COD capture at the A-stage, leading to significant energy savings from aeration for COD oxidation and post-treatment of waste sludge at the B-stage. Consequently, this study offers in-depth insights into A-B process which should be considered as an ideal candidate for achieving the energy-neutral or even energy positive operation of a municipal wastewater treatment. Given the complex situation in A-B process, future study is needed to look into the system optimization towards the operational synergy between A- and B-stage in terms of energy recovery and nitrogen removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coexistence of nitrifying, anammox and denitrifying bacteria in a sequencing batch reactor

PubMed Central

Langone, Michela; Yan, Jia; Haaijer, Suzanne C. M.; Op den Camp, Huub J. M.; Jetten, Mike S. M.; Andreottola, Gianni

2014-01-01

Elevated nitrogen removal efficiencies from ammonium-rich wastewaters have been demonstrated by several applications, that combine nitritation and anammox processes. Denitrification will occur simultaneously when organic carbon is also present. In this study, the activity of aerobic ammonia oxidizing, anammox and denitrifying bacteria in a full scale sequencing batch reactor, treating digester supernatants, was studied by means of batch-assays. AOB and anammox activities were maximum at pH of 8.0 and 7.8–8.0, respectively. Short term effect of nitrite on anammox activity was studied, showing nitrite up to 42 mg/L did not result in inhibition. Both denitrification via nitrate and nitrite were measured. To reduce nitrite-oxidizing activity, high NH3-N (1.9–10 mg NH3-N/L) and low nitrite (3–8 mg TNN/L) are required conditions during the whole SBR cycle. Molecular analysis showed the nitritation-anammox sludge harbored a high microbial diversity, where each microorganism has a specific role. Using ammonia monooxygenase α–subunit (amoA) gene as a marker, our analyses suggested different macro- and micro-environments in the reactor strongly affect the AOB community, allowing the development of different AOB species, such as N. europaea/eutropha and N. oligotropha groups, which improve the stability of nitritation process. A specific PCR primer set, used to target the 16S rRNA gene of anammox bacteria, confirmed the presence of the “Ca. Brocadia fulgida” type, able to grow in presence of organic matter and to tolerate high nitrite concentrations. The diversity of denitrifiers was assessed by using dissimilatory nitrite reductase (nirS) gene-based analyses, who showed denitifiers were related to different betaproteobacterial genera, such as Thauera, Pseudomonas, Dechloromonas and Aromatoleum, able to assist in forming microbial aggregates. Concerning possible secondary processes, no n-damo bacteria were found while NOB from the genus Nitrobacter was detected. PMID:24550899

Comparison of the efficiencies of attached- versus suspended-growth SBR systems in the treatment of recycled paper mill wastewater.

PubMed

Muhamad, Mohd Hafizuddin; Sheikh Abdullah, Siti Rozaimah; Abu Hasan, Hassimi; Abd Rahim, Reehan Adnee

2015-11-01

The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Alternating anoxic feast/aerobic famine condition for improving granular sludge formation in sequencing batch airlift reactor at reduced aeration rate.

PubMed

Wan, Junfeng; Bessière, Yolaine; Spérandio, Mathieu

2009-12-01

In this study the influence of a pre-anoxic feast period on granular sludge formation in a sequencing batch airlift reactor is evaluated. Whereas a purely aerobic SBR was operated as a reference (reactor R2), another reactor (R1) was run with a reduced aeration rate and an alternating anoxic-aerobic cycle reinforced by nitrate feeding. The presence of pre-anoxic phase clearly improved the densification of aggregates and allowed granular sludge formation at reduced air flow rate (superficial air velocity (SAV)=0.63cms(-1)). A low sludge volume index (SVI(30)=45mLg(-1)) and a high MLSS concentration (9-10gL(-1)) were obtained in the anoxic/aerobic system compared to more conventional results for the aerobic reactor. A granular sludge was observed in the anoxic/aerobic system whilst only flocs were observed in the aerobic reference even when operated at a high aeration rate (SAV=2.83cms(-1)). Nitrification was maintained efficiently in the anoxic/aerobic system even when organic loading rate (OLR) was increased up to 2.8kgCODm(-3)d(-1). In the contrary nitrification was unstable in the aerobic system and dropped at high OLR due to competition between autotrophic and heterotrophic growth. The presence of a pre-anoxic period positively affected granulation process via different mechanisms: enhancing heterotrophic growth/storage deeper in the internal anoxic layer of granule, reducing the competition between autotrophic and heterotrophic growth. These processes help to develop dense granular sludge at a moderate aeration rate. This tends to confirm that oxygen transfer is the most limiting factor for granulation at reduced aeration. Hence the use of an alternative electron acceptor (nitrate or nitrite) should be encouraged during feast period for reducing energy demand of the granular sludge process.

Sustainable multistage process for enhanced productivity of bioplastics from waste remediation through aerobic dynamic feeding strategy: Process integration for up-scaling.

PubMed

Amulya, K; Jukuri, Srinivas; Venkata Mohan, S

2015-01-01

Polyhydroxyalkanoates (PHA) production was evaluated in a multistage operation using food waste as a renewable feedstock. The first step involved the production of bio-hydrogen (bio-H2) via acidogenic fermentation. Volatile fatty acid (VFA) rich effluent from bio-H2 reactor was subsequently used for PHA production, which was carried out in two stages, Stage II (culture enrichment) and Stage III (PHA production). PHA-storing microorganisms were enriched in a sequencing batch reactor (SBR), operated at two different cycle lengths (CL-24; CL-12). Higher polymer recovery as well as VFA removal was achieved in CL-12 operation both in Stage II (16.3% dry cell weight (DCW); VFA removal, 84%) and Stage III (23.7% DCW; VFA removal, 88%). The PHA obtained was a co-polymer [P(3HB-co-3HV)] of PHB and PHV. The results obtained indicate that this integrated multistage process offers new opportunities to further leverage large scale PHA production with simultaneous waste remediation in the framework of biorefinery. Copyright © 2015 Elsevier Ltd. All rights reserved.

A feasibility study on biological nitrogen removal (BNR) via integrated thiosulfate-driven denitratation with anammox.

PubMed

Qian, Jin; Zhang, Mingkuan; Wu, Yaoguo; Niu, Juntao; Chang, Xing; Yao, Hairui; Hu, Sihai; Pei, Xiangjun

2018-06-12

To exploit the advantages of less electron donor consumptions in partial-denitrification (denitratation, NO 3 - → NO 2 - ) as well as less sludge production in autotrophic denitrification (AD) and anammox, a novel biological nitrogen removal (BNR) process through combined anammox and thiosulfate-driven denitratation was proposed here. In this study, the ratio of S 2 O 3 2- -S/NO 3 - -N and pH are confirmed to be two key factors affecting the thiosulfate-driven denitratation activity and nitrite accumulation. Simultaneous high denitratation activity and substantial nitrite accumulation were observed at initial S 2 O 3 2- -S/NO 3 - -N ratio of 1.5:1 and pH of 8.0. The optimal pH for the anammox reaction is determined to be 8.0. A sequential batch reactor (SBR) and an up-flow anaerobic sludge blanket (UASB) reactor were established to proceed the anammox and the high-rate thiosulfate-driven denitratation, respectively. Under the ambient temperature of 35 °C, the total nitrogen removal efficiency and capacity are 73% and 0.35 kg N/day/m 3 in the anammox-SBR. At HRT of 30 min, the NO 3 - removal efficiency could achieve above 90% with the nitrate-to-nitrite transformation ratio of 0.8, implying the great potential to apply the thiosulfate-driven denitratation & anammox system for BNR with minimal sludge production. Without the occurrence of denitritation (NO 2 - → N 2 O → N 2 ), theoretically no N 2 O could be emitted from this BNR system. This study could shed light on how to operate a high rate BNR system targeting to electron donor and energy savings as well as biowastes minimization and greenhouse gas reductions. Copyright © 2018. Published by Elsevier Ltd.

EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

EPA Science Inventory

The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

Effect of C/N ratio on extracellular polymeric substances of activated sludge from an anoxic-aerobic sequencing batch reactor treating saline wastewater.

PubMed

Wang, Zichao; Gao, Mengchun; Xin, Yanjun; Ma, Dong; She, Zonglian; Wang, Zhe; Sun, Changqing; Ren, Yun

2014-01-01

The effect of C/N ratio on extracellular polymeric substances (EPS) of activated sludge was investigated in an anoxic-aerobic sequencing batch reactor (SBR) treating saline wastewater. The protein (PN) and protein/polysaccharide (PN/PS) ratio in the loosely bound EPS (LB-EPS) increased with the decrease of C/N ratio, whereas the PS in the LB-EPS decreased. The PS, PN and PN/PS ratio in the tightly bound EPS (TB-EPS) were independent of C/N ratio. Two fluorescence peaks in the LB-EPS and TB-EPS were identified at excitation/emission (Ex/Em) wavelengths of 275-280/335-340 nm and 220-225/330-340 nm by three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy, respectively. These peaks in LB-EPS and TB-EPS were, respectively, associated with tryptophan protein-like substances and aromatic protein-like substances. The tryptophan protein-like fluorescence peaks in LB-EPS showed blue shift along the Ex axis and red shift along the Em axis with the decrease of C/N ratio. Fourier transform infrared spectra suggested that the variation of C/N ratio had more distinct effect on the functional groups of protein in the LB-EPS than those in the TB-EPS. The sludge volume index value decreased with the increase of LB-EPS, but there was no correlation between SVI and TB-EPS.

Illumina MiSeq sequencing reveals the key microorganisms involved in partial nitritation followed by simultaneous sludge fermentation, denitrification and anammox process.

PubMed

Wang, Bo; Peng, Yongzhen; Guo, Yuanyuan; Zhao, Mengyue; Wang, Shuying

2016-05-01

A combined process including a partial nitritation SBR (PN-SBR) followed by a simultaneous sludge fermentation, denitrification and anammox reactor (SFDA) was established to treat low C/N domestic wastewater in this study. An average nitrite accumulation rate of 97.8% and total nitrogen of 9.4mg/L in the effluent was achieved during 140days' operation. The underlying mechanisms were investigated by using Illumina MiSeq sequencing to analyze the microbial community structures in the PN-SBR and SFDA. Results showed that the predominant bacterial phylum was Proteobacteria in the external waste activated sludge (WAS, added to the SFDA) and SFDA while Bacteroidetes in the PN-SBR. Further study indicated that in the PN-SBR, the dominant nitrobacteria, Nitrosomonas genus, facilitated nitritation and little nitrate was generated in the PN-SBR effluent. In the SFDA, the co-existence of functional microorganisms Thauera, Candidatus Anammoximicrobium and Pseudomonas were found to contribute to simultaneous sludge fermentation, denitrification and anammox. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of paint shop decanter effluents on biological treatability of automotive industry wastewater.

PubMed

Güven, Didem; Hanhan, Oytun; Aksoy, Elif Ceren; Insel, Güçlü; Çokgör, Emine

2017-05-15

A lab-scale Sequencing Batch Reactor (SBR) was implemented to investigate biological treatability and kinetic characteristics of paint shop wastewater (PSW) together with main stream wastewater (MSW) of a bus production factory. Readily biodegradable and slowly biodegradable COD fractions of MWS were determined by respirometric analysis: 4.2% (S S ), 10.4% (S H ) and 59.3% (X S ). Carbon and nitrogen removal performance of the SBR feeding with MSW alone were obtained as 89% and 58%, respectively. When PSW was introduced to MSW, both carbon and nitrogen removal were deteriorated. Model simulation indicated that maximum heterotrophic growth rate decreased from 7.2 to 5.7day -1 , maximum hydrolysis rates were reduced from 6 to 4day -1 (k hS ) and 4 to 1day -1 (k hX ). Based on the dynamic model simulation for the evaluation of nitrogen removal, a maximum specific nitrifier growth rate was obtained as 0.45day -1 for MSW feeding alone. When PSW was introduced, nitrification was completely inhibited and following the termination of PSW addition, nitrogen removal performance was recovered in about 100 days, however with a much lower nitrifier growth rate (0.1day -1 ), possibly due to accumulation of toxic compounds in the sludge. Obviously, a longer recovery period is required to ensure an active nitrifier community. Copyright © 2017 Elsevier B.V. All rights reserved.

Biological groundwater treatment for chromium removal at low hexavalent chromium concentrations.

PubMed

Mamais, Daniel; Noutsopoulos, Constantinos; Kavallari, Ioanna; Nyktari, Eleni; Kaldis, Apostolos; Panousi, Eleni; Nikitopoulos, George; Antoniou, Kornilia; Nasioka, Maria

2016-06-01

The objective of this work is to develop and evaluate biological groundwater treatment systems that will achieve hexavalent chromium reduction and total chromium removal from groundwater at hexavalent chromium (Cr(VI)) groundwater concentrations in the 0-200 μg/L range. Three lab-scale units operated, as sequencing batch reactors (SBR) under aerobic, anaerobic and anaerobic-aerobic conditions. All systems received groundwater with a Cr(VI) content of 200 μg/L. In order to support biological growth, groundwater was supplemented with milk, liquid cheese whey or a mixture of sugar and milk to achieve a COD concentration of 200 mg/L. The results demonstrate that a fully anaerobic system or an anaerobic-aerobic system dosed with simple or complex external organic carbon sources can lead to practically complete Cr(VI) reduction to Cr(III). The temperature dependency of maximum Cr(VI) removal rates can be described by the Arrhenius relationship. Total chromium removal in the biological treatment systems was not complete because a significant portion of Cr(III) remained in solution. An integrated system comprising of an anaerobic SBR followed by a sand filter achieved more than 95% total chromium removal thus resulting in average effluent total and dissolved chromium concentrations of 7 μg/L and 3 μg/L, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous pyridine biodegradation and nitrogen removal in an aerobic granular system.

PubMed

Liu, Xiaodong; Wu, Shijing; Zhang, Dejin; Shen, Jinyou; Han, Weiqing; Sun, Xiuyun; Li, Jiansheng; Wang, Lianjun

2018-05-01

Simultaneous pyridine biodegradation and nitrogen removal were successfully achieved in a sequencing batch reactor (SBR) based on aerobic granules. In a typical SBR cycle, nitritation occurred obviously after the majority of pyridine was removed, while denitrification occurred at early stage of the cycle when oxygen consumption was aggravated. The effect of several key operation parameters, i.e., air flow rate, influent NH 4 + -N concentration, influent pH and pyridine concentration, on nitritation, pyridine degradation and total nitrogen (TN) removal, was systematically investigated. The results indicated that high air flow rate had a positive effect on both pyridine degradation and nitritation but a negative impact of overhigh air flow rate. With the increase of NH 4 + dosage, both nitritation and TN removal could be severely inhibited. Slightly alkaline condition, i.e., pH7.0-8.0, was beneficial for both pyridine degradation and nitritation. High pyridine dosage often resulted in the delay of both pyridine degradation and nitritation. Besides, extracellular polymeric substances production was affected by air flow rate, NH 4 + dosage, pyridine dosage and pH. In addition, high-throughput sequencing analysis demonstrated that Bdellovibrio and Paracoccus were the dominant species in the aerobic granulation system. Coexistence of pyridine degrader, nitrification related species, denitrification related species, polymeric substances producer and self-aggregation related species was also confirmed by high-throughput sequencing. Copyright © 2017. Published by Elsevier B.V.

Pre-digestion to enhance volatile fatty acids (VFAs) concentration as a carbon source for denitrification in treatment of liquid swine manure.

PubMed

Wu, Sarah Xiao; Chen, Lide; Zhu, Jun; Walquist, McKenzie; Christian, David

2018-04-30

Insufficient denitrification in biological treatment is often a result of the lack of a carbon source. In this study, use of the volatile fatty acids (VFAs) generated via pre-digestion as a carbon source to improve denitrification in sequencing batch reactor (SBR) treatment of liquid swine manure was investigated. The pre-digestion of swine manure was realized by storing the manure in a sealed container in room temperature and samples were taken periodically from the container to determine the VFA levels. The results showed that after 14 days of pre-digestion, the VFA level in the digested liquid was increased by 200%. A polynomial relationship for the VFA level in the digested manure with the digestion time was observed with a correlation coefficient being 0.9748. Two identical SBRs were built and operated on 8-h cycles in parallel, with one fed with pre-digested and the other raw swine manure. There were five phases included in each cycle, i.e., anaerobic (90 min), anoxic (150 min), anoxic/anaerobic (90 min), anoxic/aerobic (120 min), and settle/decant (30 min), and the feeding was split to 600 mL/200 mL and performed at the beginning of and 240 min into the cycle. The SBR fed on pre-digested swine manure achieved successful denitrification with only 0.35 mg/L nitrate left in the effluent, compared to 15.9 mg/L found in the effluent of the other SBR. Nitrite was not detected in the effluent from both SBRs. The results also indicated that there was no negative impact of feeding SBRs with the pre-digested liquid swine manure for treatment on the removal of other constituents such as total solids (TS), volatile solids (VS), suspended solids (SS), volatile suspended solids (VSS), and soluble chemical oxygen demand (COD). Therefore, anaerobic digestion as a pretreatment can be an effective way to condition liquid swine manure for SBR treatment to achieve sufficient nitrate removal.

Dynamics of polyhydroxyalkanoate accumulation in aerobic granules during the growth-disintegration cycle.

PubMed

Gobi, K; Vadivelu, V M

2015-11-01

The polyhydroxyalkanoate (PHA) accumulation dynamics in aerobic granules that undergo the growth-disintegration cycle were investigated. Four sequencing batch reactors (SBR) were inoculated with aerobic granules at different stages of development (different sizes). Different sizes of aerobic granules showed varying PHA contents. Thus, further study was conducted to investigate the diffusion of substrate and oxygen on PHA accumulation using various organic loading rates (OLR) and aeration rates (AR). An increase in OLR from 0.91 to 3.64kg COD/m(3)day increased the PHA content from 0.66 to 0.87g PHA/g CDW. Meanwhile, an AR increase from 1 to 4L/min only accelerated the maximum PHA accumulation without affecting the PHA content. However, the PHA composition only changes with AR, while the hydroxyvalerate (HV) content increased at a higher AR. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient anaerobic transformation of raw wheat straw by a robust cow rumen-derived microbial consortium.

PubMed

Lazuka, Adèle; Auer, Lucas; Bozonnet, Sophie; Morgavi, Diego P; O'Donohue, Michael; Hernandez-Raquet, Guillermina

2015-11-01

A rumen-derived microbial consortium was enriched on raw wheat straw as sole carbon source in a sequential batch-reactor (SBR) process under strict mesophilic anaerobic conditions. After five cycles of enrichment the procedure enabled to select a stable and efficient lignocellulolytic microbial consortium, mainly constituted by members of Firmicutes and Bacteroidetes phyla. The enriched community, designed rumen-wheat straw-derived consortium (RWS) efficiently hydrolyzed lignocellulosic biomass, degrading 55.5% w/w of raw wheat straw over 15days at 35°C and accumulating carboxylates as main products. Cellulolytic and hemicellulolytic activities, mainly detected on the cell bound fraction, were produced in the earlier steps of degradation, their production being correlated with the maximal lignocellulose degradation rates. Overall, these results demonstrate the potential of RWS to convert unpretreated lignocellulosic substrates into useful chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

A combined evaluation of the characteristics and acute toxicity of antibiotic wastewater.

PubMed

Yu, Xin; Zuo, Jiane; Li, Ruixia; Gan, Lili; Li, Zaixing; Zhang, Fei

2014-08-01

The conventional parameters and acute toxicities of antibiotic wastewater collected from each treatment unit of an antibiotic wastewater treatment plant have been investigated. The investigation of the conventional parameters indicated that the antibiotic wastewater treatment plant performed well under the significant fluctuation in influent water quality. The results of acute toxicity indicated that the toxicity of antibiotic wastewater could be reduced by 94.3 percent on average after treatment. However, treated antibiotic effluents were still toxic to Vibrio fischeri. The toxicity of antibiotic production wastewater could be attributed to the joint effects of toxic compound mixtures in wastewater. Moreover, aerobic biological treatment processes, including sequencing batch reactor (SBR) and aerobic biofilm reactor, played the most important role in reducing toxicity by 92.4 percent. Pearson׳s correlation coefficients revealed that toxicity had a strong and positive linear correlation with organic substances, nitrogenous compounds, S(2-), volatile phenol, cyanide, As, Zn, Cd, Ni and Fe. Ammonia nitrogen (NH4(+)) was the greatest contributor to toxicity according to the stepwise regression method. The multiple regression model was a good fit for [TU50-15 min] as a function of [NH₄(+)] with the determination coefficient of 0.981. Copyright © 2014 Elsevier Inc. All rights reserved.

Soil bed reactor work of the Environmental Research Lab. of the University of Arizona in support of the research and development of Biosphere 2

NASA Technical Reports Server (NTRS)

Frye, Robert

1990-01-01

Research at the Environmental Research Lab in support of Biosphere 2 was both basic and applied in nature. One aspect of the applied research involved the use of biological reactors for the scrubbing of trace atmospheric organic contaminants. The research involved a quantitative study of the efficiency of operation of Soil Bed Reactors (SBR) and the optimal operating conditions for contaminant removal. The basic configuration of a SBR is that air is moved through a living soil that supports a population of plants. Upon exposure to the soil, contaminants are either passively adsorbed onto the surface of soil particles, chemically transformed in the soil to usable compounds that are taken up by the plants or microbes as a metabolic energy source and converted to CO2 and water.

Contractor's STTR Phase I Final Report- Experimental Analysis and Model Development of Pyrolysis/Combustion of Coal/Biomass in a Bench Scale Spouted Bed Reactor

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

Baird, Benjamin; Loebick, Codruta; Roychoudhury, Subir

During Phase I both experimental evaluation and computational validation of an advanced Spouted Bed Reactor (SBR) approach for biomass and coal combustion was completed. All Phase I objectives were met and some exceeded. Comprehensive insight on SBR operation was achieved via design, fabrication, and testing of a small demonstration unit with pulverized coal and biomass as feedstock at University of Connecticut (UCONN). A scale-up and optimization tool for the next generation of coal and biomass co-firing for reducing GHG emissions was also developed. The predictive model was implemented with DOE’s MFIX computational model and was observed to accurately mimic evenmore » unsteady behavior. An updated Spouted Bed Reactor was fabricated, based on model feedback, and experimentally displayed near ideal behavior. This predictive capability based upon first principles and experimental correlation allows realistic simulation of mixed fuel combustion in these newly proposed power boiler designs. Compared to a conventional fluidized bed the SBR facilitates good mixing of coal and biomass, with relative insensitivity to particle size and densities, resulting in improved combustion efficiency. Experimental data with mixed coal and biomass fuels demonstrated complete oxidation at temperatures as low as 500ºC. This avoids NOx formation and residual carbon in the waste ash. Operation at stoichiometric conditions without requiring cooling or sintering of the carrier was also observed. Oxygen-blown operation were tested and indicated good performance. This highlighted the possibility of operating the SBR at a wide range of conditions suitable for power generation and partial oxidation byproducts. It also supports the possibility of implementing chemical looping (for readily capturing CO 2 and SO x).« less

Experimental Analysis and Model Development of Pyrolysis/Combustion of Coal/Biomass in a Bench Scale Spouted Bed Reactor.

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

Baird, Benjamin; Loebick, Codruta; Roychoudhury, Subir

During Phase I both experimental evaluation and computational validation of an advanced Spouted Bed Reactor (SBR) approach for biomass and coal combustion was completed. All Phase I objectives were met and some exceeded. Comprehensive insight on SBR operation was achieved via design, fabrication, and testing of a small demonstration unit with pulverized coal and biomass as feedstock at University of Connecticut (UCONN). A scale-up and optimization tool for the next generation of coal and biomass co-firing for reducing GHG emissions was also developed. The predictive model was implemented with DOE’s MFIX computational model and was observed to accurately mimic evenmore » unsteady behavior. An updated Spouted Bed Reactor was fabricated, based on model feedback, and experimentally displayed near ideal behavior. This predictive capability based upon first principles and experimental correlation allows realistic simulation of mixed fuel combustion in these newly proposed power boiler designs. Compared to a conventional fluidized bed the SBR facilitates good mixing of coal and biomass, with relative insensitivity to particle size and densities, resulting in improved combustion efficiency. Experimental data with mixed coal and biomass fuels demonstrated complete oxidation at temperatures as low as 500C. This avoids NOx formation and residual carbon in the waste ash. Operation at stoichiometric conditions without requiring cooling or sintering of the carrier was also observed. Oxygen-blown operation were tested and indicated good performance. This highlighted the possibility of operating the SBR at a wide range of conditions suitable for power generation and partial oxidation byproducts. It also supports the possibility of implementing chemical looping (for readily capturing CO2 and SOx).« less

Effect of UVA/LED/TiO2 photocatalysis treated sulfamethoxazole and trimethoprim containing wastewater on antibiotic resistance development in sequencing batch reactors.

PubMed

Cai, Qinqing; Hu, Jiangyong

2018-04-24

Controlling of antibiotics is the crucial step for preventing antibiotic resistance genes (ARGs) dissemination; UV photocatalysis has been identified as a promising pre-treatment technology for antibiotics removal. However, information about the effects of intermediates present in the treated antibiotics wastewater on the downstream biological treatment processes or ARGs development is very limited. In the present study, continuous UVA/LED/TiO 2 photocatalysis removed more than 90% of 100 ppb sulfamethoxazole (SMX)/trimethoprim (TMP), the treated wastewater was fed into SBR systems for over one year monitoring. Residual SMX/TMP (2-3 ppb) and intermediates present in the treated wastewater did not adversely affect SBR performance in terms of TOC and TN removal. SMX and TMP resistance genes (sulI, sulII, sulIII, dfrII, dfrV and dfr13) were also quantified in SBRs microbial consortia. Results suggested that continuous feeding of treated SMX/TMP containing wastewaters did not trigger any ARGs promotion during the one year operation. By stopping the input of 100 ppb SMX/TMP, abundance of sulII and dfrV genes were reduced by 83% and 100%, respectively. sulI gene was identified as the most persistence ARG, and controlling of 100 ppb SMX input did not achieve significant removal of sulI gene. A significant correlation between sulI gene and class 1 integrons was found at the level of p = 1.4E-10 (r = 0.94), and sulII gene positively correlated with the plasmid transfer efficiency (r = 2.442E-10, r = 0.87). Continuous input of 100 ppb SMX enhanced plasmid transfer efficiency in the SBR system, resulting in sulII gene abundance increasing more than 40 times. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

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

Liu, ZhiPing, E-mail: liulqs@163.com; Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020; Wu, WenHui

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by themore » combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.« less

Long-term performance evaluation of EBPR process in tropical climate: start-up, process stability, and the effect of operational pH and influent C:P ratio.

PubMed

Ong, Y H; Chua, A S M; Lee, B P; Ngoh, G C

2013-01-01

To date, little information is known about the operation of the enhanced biological phosphorus removal (EBPR) process in tropical climates. Along with the global concerns on nutrient pollution and the increasing array of local regulatory requirements, the applicability and compliance accountability of the EBPR process for sewage treatment in tropical climates is being evaluated. A sequencing batch reactor (SBR) inoculated with seed sludge from a conventional activated sludge (CAS) process was successfully acclimatized to EBPR conditions at 28 °C after 13 days' operation. Enrichment of Candidatus Accumulibacter phosphatis in the SBR was confirmed through fluorescence in situ hybridization (FISH). The effects of operational pH and influent C:P ratio on EBPR were then investigated. At pH 7 or pH 8, phosphorus removal rates of the EBPR processes were relatively higher when operated at C:P ratio of 3 than C:P ratio of 10, with 0.019-0.020 and 0.011-0.012 g-P/g-MLVSS•day respectively. One-year operation of the 28 °C EBPR process at C:P ratio of 3 and pH 8 demonstrated stable phosphorus removal rate of 0.020 ± 0.003 g-P/g-MLVSS•day, corresponding to effluent with phosphorus concentration <0.5 mg/L. This study provides the first evidence on good EBPR activity at relatively high temperature, indicating its applicability in a tropical climate.

Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

PubMed

Song, Yong-Hui; Qiu, Guang-Lei; Yuan, Peng; Cui, Xiao-Yu; Peng, Jian-Feng; Zeng, Ping; Duan, Liang; Xiang, Lian-Cheng; Qian, Feng

2011-06-15

Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by CO(2) stripping, and the struvite crystallization process was performed without alkali and Mg(2+) additions. Results of the long-term operation of the system showed that, both reactors provided up to 85% P removal and recovery over wide ranges of aeration times (1.0-4.0 h), hydraulic retention times (HRT) (6.0-15.0 h) and temperatures (0-29.5°C) for an extended period of 247 d, in which approximate 30% of P was recovered by the struvite accumulation devices. However, 40-90% of NH(4)(+)-N removed was through air stripping instead of being immobilized in the recovered solids. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite with purity of more than 90%. This work demonstrated the feasibility and effects of nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions. Copyright © 2011 Elsevier B.V. All rights reserved.

Biological treatment of thin-film transistor liquid crystal display (TFT-LCD) wastewater.

PubMed

Lei, C N; Whang, L M; Lin, H L

2008-01-01

The amount of pollutants produced during manufacturing processes of TFT-LCD (thin-film transistor liquid crystal display) substantially increases due to an increasing production of the opto-electronic industry in Taiwan. The total amount of wastewater from TFT-LCD manufacturing plants is expected to exceed 200,000 CMD in the near future. Typically, organic solvents used in TFT-LCD manufacturing processes account for more than 33% of the total TFT-LCD wastewater. The main components of these organic solvents are composed of the stripper (dimethyl sulphoxide (DMSO) and monoethanolamine (MEA)), developer (tetra-methyl ammonium hydroxide (TMAH)) and chelating agents. These compounds are recognized as non-or slow-biodegradable organic compounds and little information is available regarding their biological treatability. In this study, the performance of an A/O SBR (anoxic/oxic sequencing batch reactor) treating synthetic TFT-LCD wastewater was evaluated. The long-term experimental results indicated that the A/O SBR was able to achieve stable and satisfactory removal performance for DMSO, MEA and TMAH at influent concentrations of 430, 800, and 190 mg/L, respectively. The removal efficiencies for all three compounds examined were more than 99%. In addition, batch tests were conducted to study the degradation kinetics of DMSO, MEA, and TMAH under aerobic, anoxic, and anaerobic conditions, respectively. The organic substrate of batch tests conducted included 400 mg/L of DMSO, 250 mg/L of MEA, and 120 mg/L of TMAH. For DMSO, specific DMSO degradation rates under aerobic and anoxic conditions were both lower than 4 mg DMSO/g VSS-hr. Under anaerobic conditions, the specific DMSO degradation rate was estimated to be 14 mg DMSO/g VSS-hr, which was much higher than those obtained under aerobic and anoxic conditions. The optimum specific MEA and TMAH degradation rates were obtained under aerobic conditions with values of 26.5 mg MEA/g VSS-hr and 17.3 mg TMAH/g VSS-hr, respectively. Compared to aerobic conditions, anaerobic biodegradation of MEA and TMAH was much less significant with values of 5.6 mg MEA/g VSS-hr and 0 mg TMAH/g VSS-hr, respectively. In summary, biological treatment of TFT-LCD wastewater containing DMSO, MEA, and TMAH is feasible, but appropriate conditions for optimum biodegradation of DMSO, MEA, and TMAH are crucial and require carefully operational consideration. Copyright IWA Publishing 2008.

The role of salinity on the changes of the biomass characteristics and on the performance of an OMBR treating tannery wastewater.

PubMed

Luján-Facundo, M J; Fernández-Navarro, J; Alonso-Molina, J L; Amorós-Muñoz, I; Moreno, Y; Mendoza-Roca, J A; Pastor-Alcañiz, L

2018-05-25

Tannery wastewaters are difficult to treat biologically due to the high salinity and organic matter concentration. Conventional treatments, like sequential batch reactors (SBR) and membrane bioreactors (MBR), have showed settling problems, in the case of SBR, and ultrafiltration (UF) membrane fouling in the case of MBR, slowing their industrial application. In this work, the treatment of tannery wastewater with an osmotic membrane bioreactor (OMBR) is assessed. Forward osmosis (FO) membranes are characterized by a much lower fouling degree than UF membranes. The permeate passes through the membrane pores (practically only water by the high membrane rejection) from the feed solution to the draw solution, which is also an industrial wastewater (ammonia absorption effluent) in this work. Experiments were carried out at laboratory scale with a FO CTA-NW membrane from Hydration Technology Innovations (HTI). Tannery wastewater was treated by means of an OMBR using as DS an actual industrial wastewater mainly consisting of ammonium sulphate. The monitoring of the biological process was carried out with biological indicators like microbial hydrolytic enzymatic activities, dissolved and total adenosine triphosphate (ATP) in the mixed liquor and microbial population. Results indicated a limiting conductivity in the reactor of 35 mS cm -1 (on the 43th operation day), from which process was deteriorated. This process performance diminution was associated by a high decrease of the dehydrogenase activity and a sudden increase of the protease and lipase activities. The increase of the bacterial stress index also described appropriately the process performance. Regarding the relative abundance of bacterial phylotypes, 37 phyla were identified in the biomass. Proteobacteria were the most abundant (varying the relative abundance between 50.29% and 34.78%) during the first 34 days of operation. From this day on, Bacteroidetes were detected in a greater extent varying the relative abundance of this phylum between 27.20% and 40.45%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influence of biomass acclimation on the performance of a partial nitritation-anammox reactor treating industrial saline effluents.

PubMed

Giustinianovich, Elisa A; Campos, José-Luis; Roeckel, Marlene D; Estrada, Alejandro J; Mosquera-Corral, Anuska; Val Del Río, Ángeles

2018-03-01

The performance of the partial nitritation/anammox processes was evaluated for the treatment of fish canning effluents. A sequencing batch reactor (SBR) was fed with industrial wastewater, with variable salt and total ammonium nitrogen (TAN) concentrations in the range of 1.75-18.00 g-NaCl L -1 and 112 - 267 mg-TAN L -1 . The SBR operation was divided into two experiments: (A) progressive increase of salt concentrations from 1.75 to 18.33 g-NaCl L -1 ; (B) direct application of high salt concentration (18 g-NaCl L -1 ). The progressive increase of NaCl concentration provoked the inhibition of the anammox biomass by up to 94% when 18 g-NaCl L -1 were added. The stable operation of the processes was achieved after 154 days when the nitrogen removal rate was 0.021 ± 0.007 g N/L·d (corresponding to 30% of removal efficiency). To avoid the development of NOB activity at low salt concentrations and to stabilize the performance of the processes dissolved oxygen was supplied by intermittent aeration. A greater removal rate of 0.029 ± 0.017 g-N L -1 d -1 was obtained with direct exposure of the inoculum to 18 g-NaCl L -1 in less than 40 days. Also, higher specific activities than those from the inoculum were achieved for salt concentrations of 15 and 20 g-NaCl L -1 after 39 days of operation. This first study of the performance of the partial nitritation/anammox processes, to treat saline wastewaters, indicates that the acclimation period can be avoided to shorten the start-up period for industrial application purposes. Nevertheless, further experiments are needed in order to improve the efficiency of the processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradation of o-nitrophenol by aerobic granules with glucose as co-substrate.

PubMed

Basheer, Farrukh; Isa, M H; Farooqi, I H

2012-01-01

Aerobic granules to treat wastewater containing o-nitrophenol were successfully developed in a sequencing batch reactor (SBR) using activated sludge as inoculum. Stable aerobic granules were obtained with a clearly defined shape and diameters ranging from 2 to 6 mm after 122 days of operation. The integrity coefficient (IC) and granules density was found to be 98% and 1,054 kg m(-3) respectively. After development of aerobic granules, o-nitrophenols were successfully degraded to an efficiency of 78% at a concentration of 70 mg L(-1). GC-MS study revealed that the biodegradation of o-nitrophenol occurred via catechol via nitrobenzene pathway. Specific o-nitrophenol biodegradation rates followed the Haldane model and the associated kinetic parameters were found as follows: V(max) = 3.96 g o-nitrophenol g(-1)VSS(-1)d(-1), K(s) = 198.12 mg L(-1), and K(i) = 31.16 mg L(-1). The aerobic granules proved to be a feasible and effective way to degrade o-nitrophenol containing wastewater.

The start-up of denitrifying phosphorus removal system by using nitrite as electron acceptor

NASA Astrophysics Data System (ADS)

Li, W.; Liu, J.; Sun, H. Z.; Fu, J. X.; Gao, Y.; Sun, J.

2017-08-01

The inoculation of short-cut denitrifying polyphosphate-accumulating organisms (DPAOs) mainly included two-phase inoculation and three-phase inoculation. The short-cut denitrifying phosphorus removal bacteria were quickly inoculated by sequencing batch reactor (SBR) to treatment domestic wastewater. The results showed that the average effluent concentration of TP was 0.85 mg/L after 132 cycles by 44 days in two-phase inoculation. The removal rates of NO2 --N, TP and COD were 94.73%, 95.47% and 89.96% after 126 cycles by 42 days in three-phase inoculation, and the effluent concentrations were separately 1.31 mg/L, 0.45 mg/L and 17.07 mg/L, which reached the first A class requirement of Urban sewage treatment plant pollutant discharge standard. It was indicated that the efficiency of three-phase inoculation was higher. Anoxic phosphorus uptake was influenced seriously by anaerobic residual carbon, and it was the difference of the two inoculations.

Metabolic influence of lead on polyhydroxyalkanoates (PHA) production and phosphate uptake in activated sludge fed with glucose or acetic acid as carbon source.

PubMed

You, Sheng-Jie; Tsai, Yung-Pin; Cho, Bo-Chuan; Chou, Yi-Hsiu

2011-09-01

Sludge in a sequential batch reactor (SBR) system was used to investigate the effect of lead toxicity on metabolisms of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) communities fed with acetic acid or glucose as their sole carbon source, respectively. Results showed that the effect of lead on substrate utilization of both PAOs and GAOs was insignificant. However, lead substantially inhibited both of phosphate release and uptake of PAOs. In high concentration of acetic acid trials, an abnormal aerobic phosphate release was observed instead of phosphate uptake and the release rate increased with increasing lead concentration. Results also showed that PAOs could normally synthesize polyhydroxybutyrate (PHB) in the anaerobic phase even though lead concentration was 40 mg L(-1). However, they could not aerobically utilize PHB normally in the presence of lead. On the other hand, GAOs could not normally metabolize polyhydroxyvalerate (PHV) in both the anaerobic and aerobic phases. Copyright © 2011 Elsevier Ltd. All rights reserved.

PHA production by mixed cultures: a way to valorize wastes from pulp industry.

PubMed

Queirós, Diogo; Rossetti, Simona; Serafim, Luísa S

2014-04-01

In this work, hardwood spent sulfite liquor (HSSL), a complex feedstock originating from the pulp industry, was tested for the first time as a substrate for polyhydroxyalkanoate (PHA) production by a mixed microbial culture (MMC) under aerobic dynamic feeding (ADF) conditions. A sequencing batch reactor (SBR) fed with HSSL was operated for 67days and the selected MMC reached a maximum PHA content of 67.6%. The MMC demonstrated a differential utilization of the carbon sources present in HSSL. Acetic acid was fully consumed, while xylose and lignosulphonates were partially consumed (30% and 14%, respectively). The selected culture was characterized by Fluorescence in Situ Hybridization (FISH). Bacteria belonging to the three main classes were identified: Alpha- (72.7±4.0%), Beta- (11.1±0.37%) and Gammaproteobacteria (10.3±0.3%). Within Alphaproteobacteria, a small amount of Paracoccus (4.2±0.51%) and Defluvicoccus related to Tetrad Forming Organisms (9.0±0.28%) were detected. Copyright © 2014 Elsevier Ltd. All rights reserved.

40 CFR 63.1406 - Reactor batch process vent provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions by...

40 CFR 63.1406 - Reactor batch process vent provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions by...

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.

A Semi-Batch Reactor Experiment for the Undergraduate Laboratory

ERIC Educational Resources Information Center

Derevjanik, Mario; Badri, Solmaz; Barat, Robert

2011-01-01

This experiment and analysis offer an economic yet challenging semi-batch reactor experience. Household bleach is pumped at a controlled rate into a batch reactor containing pharmaceutical hydrogen peroxide solution. Batch temperature, product molecular oxygen, and the overall change in solution conductivity are metered. The reactor simulation…

40 CFR 63.1407 - Non-reactor batch process vent provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Non-reactor batch process vent... § 63.1407 Non-reactor batch process vent provisions. (a) Emission standards. (1) Owners or operators of non-reactor batch process vents located at new or existing affected sources with 0.25 tons per year (0...

40 CFR 63.1407 - Non-reactor batch process vent provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Non-reactor batch process vent... § 63.1407 Non-reactor batch process vent provisions. (a) Emission standards. (1) Owners or operators of non-reactor batch process vents located at new or existing affected sources with 0.25 tons per year (0...

Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR)

PubMed Central

Yu, Mei; Lu, Hui; Wu, Di; Zhao, Qing; Meng, Fangang; Wang, Yudan; Hao, Xiaodi; Chen, Guang-Hao

2016-01-01

In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were achieved at C/S/P/N mass ratio of 150/200/20/20, and poly-S is supplied as a potential electron and energy storage. The nitrate dosage in a range of 10–50 mg N/L had no significant influence on P uptake rates (2.1 ~ 2.4 mg P/g VSS/h), but significantly affected the storage of inclusion poly-S, the poly-S oxidation rate was increased about 16% while dosing nitrate from 20 to 30 mg N/L. It implies that nitrate is denitrified in the P uptake phase, and excess nitrate is further consumed by poly-S. Moreover, the microbial analysis showed that the functional bacteria should mostly belong to denitrifying bacteria or Unclassified genera. PMID:26983801

Relationship between modification of activated sludge wastewater treatment and changes in antibiotic resistance of bacteria.

PubMed

Korzeniewska, Ewa; Harnisz, Monika

2018-05-20

Biological treatment processes at wastewater treatment plants (WWTPs), which are the most common methods of sewage treatment, could cause selective elimination and/or changes in the proportions of phenotypes/genotypes within bacterial populations in effluent. Therefore, WWTPs based on activated sludge used in sewage treatment constitute an important reservoir of enteric bacteria which harbour potentially transferable resistance genes. Together with treated wastewater, these microorganisms can penetrate the soil, surface water, rural groundwater supplies and drinking water. Because of this, the aim of this study was to determine the impact of various modification of sewage treatment (the conventional anaerobic/anoxic/oxic (A2/O) process, mechanical-biological (MB) system, sequencing batch reactors (SBR), mechanical-biological system with elevated removal of nutrients (MB-ERN)) on the amount of antibiotic resistant bacteria (ARB) (including E. coli) and antibiotic resistance genes (ARGs) in sewage flowing out of the 13 treatment plants using activated sludge technology. There were no significant differences in ARB and ARGs regardless of time of sampling and type of treated wastewater (p > 0.05). The highest percentage of reduction (up to 99.9%) in the amount of ARB and ARGs was observed in WWTPs with MB and MB-ERN systems. The lowest reduction was detected in WWTPs with SBR. A significant increase (p < 0.05) in the percentage of bacteria resistant to the new generation antibiotics (CTX and DOX) in total counts of microorganisms was observed in effluents (EFF) from WWTPs with A2/O system and with SBR. Among all ARGs analyzed, the highest prevalence of ARGs copies in EFF samples was observed for sul1, tet(A) and qepA, the lowest for bla TEM and bla SHV . Although, the results of presented study demonstrate high efficiency of ARB and ARGs removal during the wastewater treatment processes, especially by WWTPs with MB and MB-ERN systems, EFF is still an important reservoir of ARGs which can be transferred to other microorganisms. Copyright © 2018 Elsevier B.V. All rights reserved.

Application of grey system theory on the influencing parameters of aerobic granulation in SBR.

PubMed

Bindhu, B K; Madhu, G

2017-09-01

Aerobic granulation is a promising technology for wastewater treatment. Four operational parameters were selected as influencing factors for this study. Aerobic granulation was experimented with three different values of organic loading rate (3, 6 and 9 kg COD m -3  d -1 ), superficial upflow air velocity (SUAV) (2, 3 and 4 cm s -1 ), settling time (3, 5 and 10 min) and volume exchange ratio (25%, 50% and 75%) in sequencing batch reactor in nine trials for the optimal performance of aerobic granulation. The influence of compared parameters on five reference parameters (sludge volume index (SVI), time taken for the appearance of granules, size and specific gravity of granules and chemical oxygen demand (COD) removal) was analyzed using grey system theory. The grey relational coefficients and grey entropy relational grade of each parameter were calculated. Hydrodynamic shear force in terms of SUAV was found to have the greatest influence on granule appearance, specific gravity of granules and COD removal efficiency. SVI is greatly affected by settling time. The optimal scopes of all the compared parameters were found.

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 .

Resuscitation of starved anaerobic ammonium oxidation sludge system: Impacts of repeated short-term starvation.

PubMed

Ye, Lihong; Li, Dong; Zhang, Jie; Zeng, Huiping

2018-05-04

Starvation of biomass is common during underloading of bioreactors or sludge storage in biological wastewater treatment industries. The aim of this work was to study the impact of starvation modes on the nitrogen removal capacity of anaerobic ammonium oxidation (anammox) process in sequencing batch reactor (SBR). The repeated short-term starvation and reactivation experiments were performed to evaluate the response of anammox sludge system in the condition of 27 ± 1.5 °C and 320 min HRT. Moreover, the nitrogen removal ability of the anammox process was reactivated rapidly in the low substrate condition, then the total nitrogen (TN) removal efficiency reached 82.5%, with the effluent TN of around 14.6 mgNL -1 . The repeated short-term starvation (1 day-4 days) and recovery mode could improve the tolerance and apparent activity of anammox sludge system. The dominant species of general anaerobic ammonium oxidation bacteria (AnAOB) was Candidatus Brocadia, which had better self-adaption to repeated starvation. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

PubMed

Kornaros, M; Lyberatos, G

2006-08-10

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

[Effect of pilot UASB-SFSBR-MAP process for the large scale swine wastewater treatment].

PubMed

Wang, Liang; Chen, Chong-Jun; Chen, Ying-Xu; Wu, Wei-Xiang

2013-03-01

In this paper, a treatment process consisted of UASB, step-fed sequencing batch reactor (SFSBR) and magnesium ammonium phosphate precipitation reactor (MAP) was built to treat the large scale swine wastewater, which aimed at overcoming drawbacks of conventional anaerobic-aerobic treatment process and SBR treatment process, such as the low denitrification efficiency, high operating costs and high nutrient losses and so on. Based on the treatment process, a pilot engineering was constructed. It was concluded from the experiment results that the removal efficiency of COD, NH4(+) -N and TP reached 95.1%, 92.7% and 88.8%, the recovery rate of NH4(+) -N and TP by MAP process reached 23.9% and 83.8%, the effluent quality was superior to the discharge standard of pollutants for livestock and poultry breeding (GB 18596-2001), mass concentration of COD, TN, NH4(+) -N, TP and SS were not higher than 135, 116, 43, 7.3 and 50 mg x L(-1) respectively. The process developed was reliable, kept self-balance of carbon source and alkalinity, reached high nutrient recovery efficiency. And the operating cost was equal to that of the traditional anaerobic-aerobic treatment process. So the treatment process could provide a high value of application and dissemination and be fit for the treatment pf the large scale swine wastewater in China.

Upscaling of a Batch De-Vulcanization Process for Ground Car Tire Rubber to a Continuous Process in a Twin Screw Extruder.

PubMed

Saiwari, Sitisaiyidah; van Hoek, Johannes W; Dierkes, Wilma K; Reuvekamp, Louis E A M; Heideman, Geert; Blume, Anke; Noordermeer, Jacques W M

2016-08-24

As a means to decrease the amount of waste tires and to re-use tire rubber for new tires, devulcanization of ground passenger car tires is a promising process. Being an established process for NR and EPDM, earlier work has shown that for ground passenger car tire rubber with a relatively high amount of SBR, a devulcanization process can be formulated, as well. This was proven for a laboratory-scale batch process in an internal mixer, using diphenyl disulfide as the devulcanization aid and powder-sized material. In this paper, the devulcanization process for passenger car tire rubber is upscaled from 15 g per batch and transformed into a continuous process in a co-rotating twin screw extruder with a capacity of 2 kg/h. As SBR is rather sensitive to devulcanization process conditions, such as thermal and mechanical energy input, the screw design was based on a low shear concept. A granulate with particle sizes from 1-3.5 mm was chosen for purity, as well as economic reasons. The devulcanization process conditions were fine-tuned in terms of: devulcanization conditions (time/temperature profile, concentration of devulcanization aid), extruder parameters (screw configuration, screw speed, fill factor) and ancillary equipment (pre-treatment, extrudate handling). The influence of these parameters on the devulcanization efficiency and the quality of the final product will be discussed. The ratio of random to crosslink scission as determined by a Horikx plot was taken for the evaluation of the process and material. A best practice for continuous devulcanization will be given.

Upscaling of a Batch De-Vulcanization Process for Ground Car Tire Rubber to a Continuous Process in a Twin Screw Extruder

PubMed Central

Saiwari, Sitisaiyidah; van Hoek, Johannes W.; Dierkes, Wilma K.; Reuvekamp, Louis E.A.M.; Heideman, Geert; Blume, Anke; Noordermeer, Jacques W.M.

2016-01-01

As a means to decrease the amount of waste tires and to re-use tire rubber for new tires, devulcanization of ground passenger car tires is a promising process. Being an established process for NR and EPDM, earlier work has shown that for ground passenger car tire rubber with a relatively high amount of SBR, a devulcanization process can be formulated, as well. This was proven for a laboratory-scale batch process in an internal mixer, using diphenyl disulfide as the devulcanization aid and powder-sized material. In this paper, the devulcanization process for passenger car tire rubber is upscaled from 15 g per batch and transformed into a continuous process in a co-rotating twin screw extruder with a capacity of 2 kg/h. As SBR is rather sensitive to devulcanization process conditions, such as thermal and mechanical energy input, the screw design was based on a low shear concept. A granulate with particle sizes from 1–3.5 mm was chosen for purity, as well as economic reasons. The devulcanization process conditions were fine-tuned in terms of: devulcanization conditions (time/temperature profile, concentration of devulcanization aid), extruder parameters (screw configuration, screw speed, fill factor) and ancillary equipment (pre-treatment, extrudate handling). The influence of these parameters on the devulcanization efficiency and the quality of the final product will be discussed. The ratio of random to crosslink scission as determined by a Horikx plot was taken for the evaluation of the process and material. A best practice for continuous devulcanization will be given. PMID:28773843

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.

Kinetics of D-lactic acid production by Sporolactobacillus sp. strain CASD using repeated batch fermentation.

PubMed

Zhao, Bo; Wang, Limin; Li, Fengsong; Hua, Dongliang; Ma, Cuiqing; Ma, Yanhe; Xu, Ping

2010-08-01

D-lactic acid was produced by Sporolactobacillus sp. strain CASD in repeated batch fermentation with one- and two-reactor systems. The strain showed relatively high energy consumption in its growth-related metabolism in comparison with other lactic acid producers. When the fermentation was repeated with 10% (v/v) of previous culture to start a new batch, D-lactic acid production shifted from being cell-maintenance-dependent to cell-growth-dependent. In comparison with the one-reactor system, D-lactic acid production increased approximately 9% in the fourth batch of the two-reactor system. Strain CASD is an efficient D-lactic acid producer with increased growth rate at the early stage of repeated cycles, which explains the strain's physiological adaptation to repeated batch culture and improved performance in the two-reactor fermentation system. From a kinetic point of view, two-reactor fermentation system was shown to be an alternative for conventional one-reactor repeated batch operation. Copyright 2010 Elsevier Ltd. All rights reserved.

DEMONSTRATION BULLETIN: SOIL WASHING SYSTEM - BIOTROL, INC.

EPA Science Inventory

The three component technologies of the BioTrol Soil Washing System (BSWS). Tested in the SITE demonstration were a Soil Washer (SW), and Aqueous Treatment System (ATS), and a Slurry Bio-Reactor (SBR). The Soil Washer operates on the principle that a significant fraction of the...

[Startup, stable operation and process failure of EBPR system under the low temperature and low dissolved oxygen condition].

PubMed

Ma, Juan; Li, Lu; Yu, Xiao-Jun; Wei, Xue-Fen; Liu, Juan-Li

2015-02-01

A sequencing batch reactor (SBR) was started up and operated with alternating anaerobic/oxic (An/O) to perform enhanced biological phosphorus removal (EBPR) under the condition of 13-16 degrees C. The results showed that under the condition of low temperature, the EBPR system was successfully started up in a short time (<6 d). The reactor achieved a high and stable phosphorus removal performance with an influent phosphate concentration of 20 mg x L(-1) and the dissolved oxygen (DO) concentration of 2 mg x L(-1). The effluent phosphate concentration was lower than 0.5 mg x L(-1). It was found that decreasing DO had an influence on the steady operation of EBPR system. As DO concentration of aerobic phase decreased from 2 mg x L(-1) to 1 mg x L(-1), the system could still perform EBPR and the phosphorus removal efficiency was greater than 97.4%. However, the amount of phosphate released during anaerobic phase was observed to decrease slightly compared with that of 2 mg x L(-1) DO condition. Moreover, the phosphorus removal performance of the system deteriorated immediately and the effluent phosphate concentration couldn't meet the national integrated wastewater discharge standard when DO concentration was further lowered to 0.5 mg x L(-1). The experiments of increasing DO to recover phosphorus removal performance of the EBPR suggested the process failure resulted from low DO was not reversible in the short-term. It was also found that the batch tests of anoxic phosphorus uptake using nitrite and nitrate as electron acceptors had an impact on the stable operation of EBPR system, whereas the resulting negative influence could be recovered within 6 cycles. In addition, the mixed liquid suspended solids (MLSS) of the EBPR system remained stable and the sludge volume index (SVI) decreased to a certain extend in a long run, implying long-term low temperature and low DO condition favored the sludge sedimentation.

REUSABLE ADSORBENTS FOR DILUTE SOLUTIONS SEPARATION. 6. BATCH AND CONTINUOUS REACTORS FOR ADSORPTION AND DEGRADATION OF 1,2-DICHLOROBENZENE FROM DILUTE WASTEWATER STREAMS USING TITANIA AS A PHOTOCATALYST. (R828598C753)

EPA Science Inventory

Two types of external lamp reactors were investigated for the titania catalyzed photodegradation of 1,2-dichlorobenzene (DCB) from a dilute water stream. The first one was a batch mixed slurry reactor and the second one was a semi-batch reactor with continuous feed recycle wit...

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

Catalytic wet oxidation of phenol in a trickle bed reactor over a Pt/TiO2 catalyst.

PubMed

Maugans, Clayton B; Akgerman, Aydin

2003-01-01

Catalytic wet oxidation of phenol was studied in a batch and a trickle bed reactor using 4.45% Pt/TiO2 catalyst in the temperature range 150-205 degrees C. Kinetic data were obtained from batch reactor studies and used to model the reaction kinetics for phenol disappearance and for total organic carbon disappearance. Trickle bed experiments were then performed to generate data from a heterogeneous flow reactor. Catalyst deactivation was observed in the trickle bed reactor, although the exact cause was not determined. Deactivation was observed to linearly increase with the cumulative amount of phenol that had passed over the catalyst bed. Trickle bed reactor modeling was performed using a three-phase heterogeneous model. Model parameters were determined from literature correlations, batch derived kinetic data, and trickle bed derived catalyst deactivation data. The model equations were solved using orthogonal collocations on finite elements. Trickle bed performance was successfully predicted using the batch derived kinetic model and the three-phase reactor model. Thus, using the kinetics determined from limited data in the batch mode, it is possible to predict continuous flow multiphase reactor performance.

The use of used automobile tyres in a partitioning bioreactor for the biodegradation of xenobiotic mixtures.

PubMed

Tomeia, M Concetta; Angeluccia, Domenica Mosca; Daugulis, Andrew J

2014-01-01

Waste tyres were utilized as the sorption phase in a two-phase partitioning bioreactor (TPPB) for the biodegradation of a binary mixture of 2,4-dichlorophenol (DCP) and 4-nitrophenol (4NP). These compounds are extensively used in the chemical industry and are found in many industrial effluents. Although both compounds are toxic and are on the EPA list of priority pollutants, a higher inhibitory effect on microorganisms is exerted by DCP, and our experimental tests were focused on strategies to reduce its negative impact on microbial activity. Sorption/desorption tests for the DCP-4NP mixture were first performed to verify the related uptake/release rates by the tyres, which showed that the tyres had a higher capacity for DCP uptake and practically no affinity for 4NP. An acclimatized mixed culture was then utilized in a sequencing batch reactor (SBR) operated in conventional and two-phase mode. For the binary DCP-4NP mixture a significant reduction in DCP toxicity, and a concomitant enhancement in substrate removal efficiency (up to 83%for DCP and approximate 100% for 4NP) were clearly seen for the TPPB operated with 10% and 15% v/v tyres, for influent concentrations up to 180 mg/L, with practically negligible biodegradation in the conventional single phase reactor. The long-term utilization of tyres was confirmed at an influent loading of 180 mg/L with a test performed over 20 work cycles showing an improvement of the removal performance for both compounds.

[Study of ammonium-nitrogen removal in suspended carrier biofilm reactor].

PubMed

Wang, Wen-bin; Qi, Pei-shi

2006-12-01

In order to improve the ammonium-nitrogen (NH4+ -N) biodegradation rate, a suspended carrier was exploited and biofilm was cultivated in three different phases in a sequencing batch reactor (SBR). A flimsy honeycomb-shape biofilm was formed between the endocentric columns on the suspended carrier,which increased the cling amount of nitrobacteria and provided the better condition for nitrobacteria. The bioreactor was operated at the temperature ranges of 24-29 degrees C and pH between 7.8 and 8.2. When the influent COD and NH4+-N concentrations varied in a range of 140-300 mg x L(-1) and 40- 78 mg x L(-1) , respectively, under 90 min aeration, the effluent concentrations were less than 40 mg x L(-1) and 2 mg x L(-1) , respectively. Under 180 min aeration, the influent COD concentration varied from 150 to 350 mg x L(-1) and NH4+-N concentration in the range of 80 - 130 mg x L (-1), the effluent concentration below 45 mg x L(-1) and 3.5 mg x L(-1), respectively. The results indicated that the ammonium-nitrogen biodegradation rate is much greater than that of the conventional activated sludge process. The active fraction of the biofilm is affected by the concentration of substrates in the bulk liquid, the actual metabolic rates within the biofilm, and the thickness of the biofilm. The suspended carrier configuration used in this investigation and the method of cultivating biofilm are beneficial for decreasing biofilm thickness, for increasing the activated biomass of nitrobacteria, and for increasing surface area of the biofilm relative to the volume of the reactors, which insulting in a high rate of nitrification.

A novel aerated surface flow constructed wetland using exhaust gas from biological wastewater treatment: Performance and mechanisms.

PubMed

Zhang, Xinwen; Hu, Zhen; Zhang, Jian; Fan, Jinlin; Ngo, Huu Hao; Guo, Wenshan; Zeng, Chujun; Wu, Yiwen; Wang, Siyuan

2018-02-01

In this study, a novel aerated surface flow constructed wetland (SFCW) using exhaust gas from biological wastewater treatment was investigated. Compared with un-aerated SFCW, the introduction of exhaust gas into SFCW significantly improved NH 4 + -N, TN and COD removal efficiencies by 68.30 ± 2.06%, 24.92 ± 1.13% and 73.92 ± 2.36%, respectively. The pollutants removal mechanism was related to the microbial abundance and the highest microbial abundance was observed in the SFCW with exhaust gas because of the introduction of exhaust gas from sequencing batch reactor (SBR), and thereby optimizing nitrogen transformation processes. Moreover, SFCW would significantly mitigate the risk of exhaust gas pollution. SFCW removed 20.00 ± 1.23%, 34.78 ± 1.39%, and 59.50 ± 2.33% of H 2 S, NH 3 and N 2 O in the exhaust gas, respectively. And 31.32 ± 2.23% and 32.02 ± 2.86% of bacterial and fungal aerosols in exhaust gas were also removed through passing SFCW, respectively. Copyright © 2017. Published by Elsevier Ltd.

The influence of pH adjustment on kinetics parameters in tapioca wastewater treatment using aerobic sequencing batch reactor system

NASA Astrophysics Data System (ADS)

Mulyani, Happy; Budianto, Gregorius Prima Indra; Margono, Kaavessina, Mujtahid

2018-02-01

The present investigation deals with the aerobic sequencing batch reactor system of tapioca wastewater treatment with varying pH influent conditions. This project was carried out to evaluate the effect of pH on kinetics parameters of system. It was done by operating aerobic sequencing batch reactor system during 8 hours in many tapioca wastewater conditions (pH 4.91, pH 7, pH 8). The Chemical Oxygen Demand (COD) and Mixed Liquor Volatile Suspended Solids (MLVSS) of the aerobic sequencing batch reactor system effluent at steady state condition were determined at interval time of two hours to generate data for substrate inhibition kinetics parameters. Values of the kinetics constants were determined using Monod and Andrews models. There was no inhibition constant (Ki) detected in all process variation of aerobic sequencing batch reactor system for tapioca wastewater treatment in this study. Furthermore, pH 8 was selected as the preferred aerobic sequencing batch reactor system condition in those ranging pH investigated due to its achievement of values of kinetics parameters such µmax = 0.010457/hour and Ks = 255.0664 mg/L COD.

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.

Batch Tests To Determine Activity Distribution and Kinetic Parameters for Acetate Utilization in Expanded-Bed Anaerobic Reactors

PubMed Central

Fox, Peter; Suidan, Makram T.

1990-01-01

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen, Methanothrix sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (Ks) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for Ks. However, Ks was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of Ks on the effluent 3-ethylphenol concentration. A two-parameter search determined a Ks of 8.99 mg of acetate per liter and a Ki of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made. PMID:16348175

Batch tests to determine activity distribution and kinetic parameters for acetate utilization in expanded-bed anaerobic reactors.

PubMed

Fox, P; Suidan, M T

1990-04-01

Batch tests to measure maximum acetate utilization rates were used to determine the distribution of acetate utilizers in expanded-bed sand and expanded-bed granular activated carbon (GAC) reactors. The reactors were fed a mixture of acetate and 3-ethylphenol, and they contained the same predominant aceticlastic methanogen, Methanothrix sp. Batch tests were performed both on the entire reactor contents and with media removed from the reactors. Results indicated that activity was evenly distributed within the GAC reactors, whereas in the sand reactor a sludge blanket on top of the sand bed contained approximately 50% of the activity. The Monod half-velocity constant (K(s)) for the acetate-utilizing methanogens in two expanded-bed GAC reactors was searched for by combining steady-state results with batch test data. All parameters necessary to develop a model with Monod kinetics were experimentally determined except for K(s). However, K(s) was a function of the effluent 3-ethylphenol concentration, and batch test results demonstrated that maximum acetate utilization rates were not a function of the effluent 3-ethylphenol concentration. Addition of a competitive inhibition term into the Monod expression predicted the dependence of K(s) on the effluent 3-ethylphenol concentration. A two-parameter search determined a K(s) of 8.99 mg of acetate per liter and a K(i) of 2.41 mg of 3-ethylphenol per liter. Model predictions were in agreement with experimental observations for all effluent 3-ethylphenol concentrations. Batch tests measured the activity for a specific substrate and determined the distribution of activity in the reactor. The use of steady-state data in conjunction with batch test results reduced the number of unknown kinetic parameters and thereby reduced the uncertainty in the results and the assumptions made.

Shortcut nitrification/partial nitritation start-up for reject water treatment in a SBR

NASA Astrophysics Data System (ADS)

Muszyński-Huhajło, Mateusz; Miodoński, Stanisław

2017-11-01

For many wastewater treatment plants (WWTPs), side-stream treatment of reject water from digested sludge dewatering is a feasible opportunity to improve N-removal efficiency without costly plant expansion. Biological nitrogen removal over nitrite or combined partial nitritation (PN)-Anammox process has recently become a popular treatment method for such ammonium-rich streams. Shortcut nitrification and PN start-ups were successfully performed in a pilot-scale SBR treating real reject water. In all performed experiments, effective nitrate production inhibition occurred in less than 20 days due to operational conditions selection and without advanced control system. pH adjustment in the PN reactor allowed to achieve NO2-N /NH4-N ratio suitable for Anammox process (1.24±0.07).

Organics, sulfates and ammonia removal from acrylic fiber manufacturing wastewater using a combined Fenton-UASB (2 phase)-SBR system.

PubMed

Li, Jin; Luan, Zhaokun; Yu, Lian; Ji, Zhongguang

2011-11-01

A combined Fenton-UASB (2 phase)-SBR system was employed to treat acrylic fiber manufacturing wastewater. The Chemical Oxygen Demand (COD) removal and effluent Biochemical Oxygen Demand (BOD) to COD were 65.5% and 0.529%, respectively, with the optimal Fenton conditions: ferrous was 300 mg/L; hydrogen peroxide was 500 mg/L; pH was 3.0; reaction time was 2.0 h. In two-phase UASB reactor, mesophilic operation (35±0.5 °C) was performed with hydraulic retention time (HRT) varied between 28 and 40 h. The results showed that with the HRT not less than 38 h, COD and sulfate removal were 65% and 75%, respectively. The greatest sizes of granule formed in the sulfate-reducing and methane-producing phases were 5 and 2 mm, respectively. Sulfate-reducing bacteria (SRB) accounted for 35% in the sulfate-reducing phase while methane-producing archaea (MPA) accounted for 72% in the methane-producing phase. During the SBR process, shortcut nitrification was achieved by temperature control of 30 °C. Copyright © 2011 Elsevier Ltd. All rights reserved.

Different cultivation methods to acclimatise ammonia-tolerant methanogenic consortia.

PubMed

Tian, Hailin; Fotidis, Ioannis A; Mancini, Enrico; Angelidaki, Irini

2017-05-01

Bioaugmentation with ammonia tolerant-methanogenic consortia was proposed as a solution to overcome ammonia inhibition during anaerobic digestion process recently. However, appropriate technology to generate ammonia tolerant methanogenic consortia is still lacking. In this study, three basic reactors (i.e. batch, fed-batch and continuous stirred-tank reactors (CSTR)) operated at mesophilic (37°C) and thermophilic (55°C) conditions were assessed, based on methane production efficiency, incubation time, TAN/FAN (total ammonium nitrogen/free ammonia nitrogen) levels and maximum methanogenic activity. Overall, fed-batch cultivation was clearly the most efficient method compared to batch and CSTR. Specifically, by saving incubation time up to 150%, fed-batch reactors were acclimatised to nearly 2-fold higher FAN levels with a 37%-153% methanogenic activity improvement, compared to batch method. Meanwhile, CSTR reactors were inhibited at lower ammonia levels. Finally, specific methanogenic activity test showed that hydrogenotrophic methanogens were more active than aceticlastic methanogens in all FAN levels above 540mgNH 3 -NL -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential of hydrolysis of particulate COD in extended anaerobic conditions to enhance biological phosphorous removal.

PubMed

Jabari, P; Yuan, Q; Oleszkiewicz, J A

2016-11-01

The effect of anaerobic hydrolysis of particulate COD (pCOD) on biological phosphorous removal in extended anaerobic condition was investigated through (i) sequencing batch reactors (SBR)s with anaerobic hydraulic retention time (HRT) of 0.8, 2, and 4 h; (ii) batch tests using biomass from a full scale biological nutrient removal (BNR) plant; and (iii) activated sludge modeling (BioWin 4.1 simulation). The results from long-term SBRs operation showed that phosphorus removal was correlated to the ratio of filtered COD (FCOD) to total phosphorus (TP) in the influent. Under conditions with low FCOD/TP ratio (average of 20) in the influent, extending anaerobic HRT to 4 h in the presence of pCOD did not significantly improve overall phosphorous removal. During the period with high FCOD/TP ratio (average of 37) in the influent, all SBRs removed phosphorous completely, and the long anaerobic HRT did not have negative effect on overall phosphorous removal. The batch tests also showed that pCOD at different concentration during 4 h test did not affect the rate of anaerobic phosphorus release. The rate of anaerobic hydrolysis of pCOD was significantly low and extending the anaerobic HRT was ineffective. The simulation (BioWin 4.1) of SBRs with low influent FCOD/TP ratio showed that the default kinetics of anaerobic hydrolysis in ASM2d overestimated phosphorous removal in the SBRs (high anaerobic hydrolysis of pCOD). The default anaerobic hydrolysis rate in BioWin 4.1 (ten times lower) could produce similar phosphorous removal to that in the experiment. Results showed that the current kinetics of anaerobic hydrolysis in ASM2d could lead to considerable error in predicting phosphorus removal in processes with extended anaerobic HRT. Biotechnol. Bioeng. 2016;113: 2377-2385. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

CONVERTING FROM BATCH TO CONTINUOUS INTENSIFIED PROCESSING IN THE STT? REACTOR

EPA Science Inventory

The fluid dynamics, the physical dimensions and characteristics of the reaction zones of continuous process intensification reactors are often quite different from those of the batch reactors they replace. Understanding these differences is critical to the successful transit...

Morphological evolution of copper nanoparticles: Microemulsion reactor system versus batch reactor system

NASA Astrophysics Data System (ADS)

Xia, Ming; Tang, Zengmin; Kim, Woo-Sik; Yu, Taekyung; Park, Bum Jun

2017-07-01

In the synthesis of nanoparticles, the reaction rate is important to determine the morphology of nanoparticles. We investigated morphology evolution of Cu nanoparticles in this two different reactors, microemulsion reactor and batch reactor. In comparison with the batch reactor system, the enhanced mass and heat transfers in the emulsion system likely led to the relatively short nucleation time and the highly homogeneous environment in the reaction mixture, resulting in suppressing one or two dimensional growth of the nanoparticles. We believe that this work can offer a good model system to quantitatively understand the crystal growth mechanism that depends strongly on the local monomer concentration, the efficiency of heat transfer, and the relative contribution of the counter ions (Br- and Cl-) as capping agents.

PREMOR: a point reactor exposure model computer code for survey analysis of power plant performance

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

Vondy, D.R.

1979-10-01

The PREMOR computer code was written to exploit a simple, two-group point nuclear reactor power plant model for survey analysis. Up to thirteen actinides, fourteen fission products, and one lumped absorber nuclide density are followed over a reactor history. Successive feed batches are accounted for with provision for from one to twenty batches resident. The effect of exposure of each of the batches to the same neutron flux is determined.

Nitrous oxide reduction genetic potential from the microbial community of an intermittently aerated partial nitritation SBR treating mature landfill leachate.

PubMed

Gabarró, J; Hernández-Del Amo, E; Gich, F; Ruscalleda, M; Balaguer, M D; Colprim, J

2013-12-01

This study investigates the microbial community dynamics in an intermittently aerated partial nitritation (PN) SBR treating landfill leachate, with emphasis to the nosZ encoding gene. PN was successfully achieved and high effluent stability and suitability for a later anammox reactor was ensured. Anoxic feedings allowed denitrifying activity in the reactor. The influent composition influenced the mixed liquor suspended solids concentration leading to variations of specific operational rates. The bacterial community was low diverse due to the stringent conditions in the reactor, and was mostly enriched by members of Betaproteobacteria and Bacteroidetes as determined by 16S rRNA sequencing from excised DGGE melting types. The qPCR analysis for nitrogen cycle-related enzymes (amoA, nirS, nirK and nosZ) demonstrated high amoA enrichment but being nirS the most relatively abundant gene. nosZ was also enriched from the seed sludge. Linear correlation was found mostly between nirS and the organic specific rates. Finally, Bacteroidetes sequenced in this study by 16S rRNA DGGE were not sequenced for nosZ DGGE, indicating that not all denitrifiers deal with complete denitrification. However, nosZ encoding gene bacteria was found during the whole experiment indicating the genetic potential to reduce N2O. Copyright © 2013 Elsevier Ltd. All rights reserved.

Strategies for the startup of methanogenic inverse fluidized-bed reactors using colonized particles.

PubMed

Alvarado-Lassman, A; Sandoval-Ramos, A; Flores-Altamirano, M G; Vallejo-Cantú, N A; Méndez-Contreras, J M

2010-05-01

One of the inconveniences in the startup of methanogenic inverse fluidized-bed reactors (IFBRs) is the long period required for biofilm formation and stabilization of the system. Previous researchers have preferred to start up in batch mode to shorten stabilization times. Much less work has been done with continuous-mode startup for the IFBR configuration of reactors. In this study, we prepared two IFBRs with similar characteristics to compare startup times for batch- and continuous-operation modes. The reactors were inoculated with a small quantity of colonized particles and run for a period of 3 months, to establish the optimal startup strategy using synthetic media as a substrate (glucose as a source of carbon). After the startup stage, the continuous- and batch-mode reactors removed more than 80% of the chemical oxygen demand (COD) in 51 and 60 days of operation, respectively; however, at the end of the experiments, the continuous-mode reactor had more biomass attached to the support media than the batch-mode reactor. Both reactors developed fully covered support media, but only the continuous-mode reactor had methane yields close to the theoretical value that is typical of stable reactors. Then, a combined startup strategy was proposed, with industrial wastewater as the substrate, using a sequence of batch cycles followed by continuous operation, which allows stable operation at an organic loading rate of 20 g COD/L x d in 15 days. Using a fraction of colonized support as an inoculum presents advantages, with respect to previously reported strategies.

Effect of air flow rate on development of aerobic granules, biomass activity and nitrification efficiency for treating phenol, thiocyanate and ammonium.

PubMed

Tomar, Sachin Kumar; Chakraborty, Saswati

2018-08-01

The impact of air flow rate on aerobic granulation was evaluated for treating toxic multiple pollutants; phenol (400 mg L -1 ), thiocyanate (100 mg L -1 ) and ammonia nitrogen (100 mg L -1 ) by using three lab scale sequencing batch reactors (SBRs) (R1, R2 and R3). Larger granules (2938.67 ± 64.91 μm) with higher biomass concentration (volatile solids of 4.17 ± 0.09 g L -1 ), higher granule settling velocity (55.56 ± 1.36 m h -1 ) and lower sludge volume index (35.25 ± 1.71 mL gTSS -1 ) were observed at optimal air flow rate of 2.5 L min -1 (R2). Confocal laser scanning microscopic images illustrated the extended fluorescence for extracellular polymeric substances in R2. In R2, partial nitrification was achieved. Phenol was completely removed in all the reactors while partial removal of SCN - and no nitrification were observed with a decrease (1.5 L min -1 ) and an increase (3.5 L min -1 ) in air flow rates (R1 and R3, respectively). This study provides an experimental contribution to examine the effect of optimal combination of aeration and toxic multiple pollutants, governing characteristics and nitrification efficiency of granules along with SBR performance in an economic way in terms of optimal air supply. Copyright © 2018 Elsevier Ltd. All rights reserved.

Utilization of Stop-flow Micro-tubing Reactors for the Development of Organic Transformations.

PubMed

Toh, Ren Wei; Li, Jie Sheng; Wu, Jie

2018-01-04

A new reaction screening technology for organic synthesis was recently demonstrated by combining elements from both continuous micro-flow and conventional batch reactors, coined stop-flow micro-tubing (SFMT) reactors. In SFMT, chemical reactions that require high pressure can be screened in parallel through a safer and convenient way. Cross-contamination, which is a common problem in reaction screening for continuous flow reactors, is avoided in SFMT. Moreover, the commercially available light-permeable micro-tubing can be incorporated into SFMT, serving as an excellent choice for light-mediated reactions due to a more effective uniform light exposure, compared to batch reactors. Overall, the SFMT reactor system is similar to continuous flow reactors and more superior than batch reactors for reactions that incorporate gas reagents and/or require light-illumination, which enables a simple but highly efficient reaction screening system. Furthermore, any successfully developed reaction in the SFMT reactor system can be conveniently translated to continuous-flow synthesis for large scale production.

Central waste processing system

NASA Technical Reports Server (NTRS)

Kester, F. L.

1973-01-01

A new concept for processing spacecraft type wastes has been evaluated. The feasibility of reacting various waste materials with steam at temperatures of 538 - 760 C in both a continuous and batch reactor with residence times from 3 to 60 seconds has been established. Essentially complete gasification is achieved. Product gases are primarily hydrogen, carbon dioxide, methane, and carbon monoxide. Water soluble synthetic wastes are readily processed in a continuous tubular reactor at concentrations up to 20 weight percent. The batch reactor is able to process wet and dry wastes at steam to waste weight ratios from 2 to 20. Feces, urine, and synthetic wastes have been successfully processed in the batch reactor.

Evaluation of Municipal Wastewater Treatment Plant Activated Sludge for Biodegradation of Propylene Glycol as an Aircraft Deicing Fluid

DTIC Science & Technology

2012-03-01

Propylene Glycol Deicer Biodegredation Kinetics: Complete-Mix Stirred Tank Reactors , Filter, and Fluidized Bed . Journal of Environmental...scale sequencing batch reactor containing municipal waste water treatment facility activated sludge (AS) performing simultaneous organic carbon...Sequencing Batch Reactor Operation ..................................................................... 13 PG extraction from AS

Spatial distribution and removal performance of pharmaceuticals in municipal wastewater treatment plants in China.

PubMed

Liu, Hou-Qi; Lam, James C W; Li, Wen-Wei; Yu, Han-Qing; Lam, Paul K S

2017-05-15

Municipal wastewater treatment plants (WWTPs) are an important source of pharmaceuticals released into the environment. Understanding how various pharmaceuticals are distributed and handled in WWTPs is a prerequisite to optimize their abatement. Here we investigated the spatial distribution and removal efficiencies pharmaceuticals in China's WWTPs. A total of 35 pharmaceuticals in wastewater samples from 12 WWTPs at different cities of China were analyzed. Among these detected pharmaceuticals, caffeine showed the highest concentration (up to 1775.98ngL -1 ) in the WWTP influent. In addition, there were significant regional differences in pharmaceutical distribution with higher influent concentrations of total pharmaceuticals detected in WWTPs in the northern cities than the southern ones. The state-of-the-art treatment processes were generally inefficient in removing pharmaceuticals. Only 14.3% of pharmaceuticals were removed effectively (mean removal efficiency>70%), while 51.4% had a removal rate of below 30%. The anaerobic/anoxic/oxic (AAO)-membrane bioreactor (MBR) integrated process and sequencing batch reactor (SBR) showed better performance than the AAO and oxidation ditch (OD) processes. Ofloxacin, erythromycin-H 2 O, clarithromycin, roxithromycin and sulfamethoxazole in WWTP effluents exhibited a high or medium ecological risk and deserved special attention. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of an aniline supplement on the stability of aerobic granular sludge.

PubMed

Dai, Yajie; Jiang, Yixin; Su, Haijia

2015-10-01

In order to evaluate the stability of aerobic granules in a toxic environment, this study discussed the influence of an aniline supplement on the properties and microbial community of aerobic granules. In the early stages of sequencing batch reactor (SBR) operation, an aniline supplement slightly affected the properties of the aerobic granules (strength, growth rate, SVI and so on). This effect was thereafter removed because of a change in the microbial community and the structure of aerobic granules: with the present of aniline, microbes with biodegradation ability appeared and gathered in the aerobic granules and the aerobic granules densified and settled faster as their SVI decreased to 35 mL/g and settling velocity increased to 41.56 m/h. When a synthetic waste water containing acetate as carbon source was used as influent, aniline (10-500 mg/L) could be degraded in 6 h, at a rate as high as 37.5 mg aniline/(L·h), with a removal rate in excess of 90%, while the effluent COD fell below 100 mg/L from the initial about 2000 mg/L. The aerobic granules cultured by acetate were compact, stable and resistant to aniline. Copyright © 2015 Elsevier Ltd. All rights reserved.

Perchlorate and nitrate treatment by ion exchange integrated with biological brine treatment.

PubMed

Lehman, S Geno; Badruzzaman, Mohammad; Adham, Samer; Roberts, Deborah J; Clifford, Dennis A

2008-02-01

Groundwater contaminated with perchlorate and nitrate was treated in a pilot plant using a commercially available ion exchange (IX) resin. Regenerant brine concentrate from the IX process, containing high perchlorate and nitrate, was treated biologically and the treated brine was reused in IX resin regeneration. The nitrate concentration of the feed water determined the exhaustion lifetime (i.e., regeneration frequency) of the resin; and the regeneration condition was determined by the perchlorate elution profile from the exhausted resin. The biological brine treatment system, using a salt-tolerant perchlorate- and nitrate-reducing culture, was housed in a sequencing batch reactor (SBR). The biological process consistently reduced perchlorate and nitrate concentrations in the spent brine to below the treatment goals of 500 microg ClO4(-)/L and 0.5mg NO3(-)-N/L determined by equilibrium multicomponent IX modeling. During 20 cycles of regeneration, the system consistently treated the drinking water to below the MCL of nitrate (10 mgNO3(-)-N/L) and the California Department of Health Services (CDHS) notification level of perchlorate (i.e., 6 microg/L). A conceptual cost analysis of the IX process estimated that perchlorate and nitrate treatment using the IX process with biological brine treatment to be approximately 20% less expensive than using the conventional IX with brine disposal.

Aeration control strategies to stimulate simultaneous nitrification-denitrification via nitrite during the formation of aerobic granular sludge.

PubMed

Dobbeleers, Thomas; D'aes, Jolien; Miele, Solange; Caluwé, Michel; Akkermans, Veerle; Daens, Dominique; Geuens, Luc; Dries, Jan

2017-09-01

In this study, a sequencing batch reactor (SBR), treating synthetic wastewater (COD/N = 5), was operated in two stages. During stage I, an aeration control strategy based on oxygen uptake rate (OUR) was applied, to accomplish nitrogen removal via nitrite >80%. In stage II, the development of aerobic granular sludge (AGS) was examined while two aeration control strategies (OUR and pH slope) maintained the nitrite pathway and optimized the simultaneous nitrification-denitrification (SND) performance. Stimulation of slow-growing organisms, (denitrifying) polyphosphate-accumulating organisms (D)PAO and (denitrifying) glycogen-accumulating organisms (D)GAO leads to full granulation (at day 200, SVI 10  = 47.0 mL/g and SVI 30  = 43.1 mL/g). The average biological nutrient removal efficiencies, for nitrogen and phosphorus, were 94.6 and 83.7%, respectively. Furthermore, the benefits of an increased dissolved oxygen concentration (1.0-2.0 mg O 2 /L) were shown as biomass concentrations increased with approximately 2 g/L, and specific ammonium removal rate and phosphorus uptake rate increased with 33 and 44%, respectively. It was shown that the combination of both aeration phase-length control strategies provided an innovative method to achieve SND via nitrite in AGS.

Transformation of metals speciation in a combined landfill leachate treatment.

PubMed

Wu, Yanyu; Zhou, Shaoqi; Chen, Dongyu; Zhao, Rong; Li, Huosheng; Lin, Yiming

2011-04-01

Landfill leachate was treated by a combined sequential batch reactor (SBR), coagulation, Fenton oxidation and biological aerated filter (BAF) technology. The metals in treatment process were fractionated into three fractions: particulate and colloidal (size charge filtration), free ion/labile (cation exchange) and non-labile fractions. Fifty percent to 66% Cu, Ni, Zn, Mn, Pb and Cd were present as particulate/colloidal matter in raw leachate, whereas Cr was present 94.9% as non-labile complexes. The free ion/labile fractions of Ni, Zn, Mg, Mn, Pb and Cd increased significantly after treatment except Cr. Fifty-nine percent to 100% of Al was present mainly as particulate/colloidal matter >0.45 μm and the remaining portions were predicted as non-labile complexes except in coagulation effluent. The speciation of Fe varied significantly in various individual processes. Visual MINTEQ simulation showed that 95-100% colloidal species for Cu, Cd and Pb were present as metal-humic complexes even with the lower dissolved organic carbon. Optimum agreements for the free ion/labile species were within acidic solution, whereas under-estimated in alkaline effluents. Overestimated particulate/colloidal fraction consisted with the hypothesis that a portion of colloids in fraction <0.45 μm were considered as dissolved. Copyright © 2011 Elsevier B.V. All rights reserved.

Electrochemical treatment of tannery effluent using a battery integrated DC-DC converter and solar PV power supply--an approach towards environment and energy management.

PubMed

Iyappan, K; Basha, C Ahmed; Saravanathamizhan, R; Vedaraman, N; Tahiyah Nou Shene, C A; Begum, S Nathira

2014-01-01

Electrochemical oxidation of tannery effluent was carried out in batch, batch recirculation and continuous reactor configurations under different conditions using a battery-integrated DC-DC converter and solar PV power supply. The effect of current density, electrolysis time and fluid flow rate on chemical oxygen demand (COD) removal and energy consumption has been evaluated. The results of batch reactor show that a COD reduction of 80.85% to 96.67% could be obtained. The results showed that after 7 h of operation at a current density of 2.5 A dm(-2) and flow rate of 100 L h(-1) in batch recirculation reactor, the removal of COD is 82.14% and the specific energy consumption was found to be 5.871 kWh (kg COD)(-1) for tannery effluent. In addition, the performance of single pass flow reactors (single and multiple reactors) system of various configurations are analyzed.

Cadmium removal using Cladophora in batch, semi-batch and flow reactors.

PubMed

Sternberg, Steven P K; Dorn, Ryan W

2002-02-01

This study presents the results of using viable algae to remove cadmium from a synthetic wastewater. In batch and semi-batch tests, a local strain of Cladophora algae removed 80-94% of the cadmium introduced. The flow experiments that followed were conducted using non-local Cladophora parriaudii. Results showed that the alga removed only 12.7(+/-6.4)% of the cadmium introduced into the reactor. Limited removal was the result of insufficient algal quantities and poor contact between the algae and cadmium solution.

Cultivation of E. coli in single- and ten-stage tower-loop reactors.

PubMed

Adler, I; Schügerl, K

1983-02-01

E. Coli was cultivated in batch and continuous operations in the presence of an antifoam agent in stirred-tank and in single- and ten-stage airlift tower reactors with an outer loop. The maximum specific growth rate, mu(m), the substrate yield coefficient, Y(x/s), the respiratory quotient, RQ, substrate conversion, U(s), the volumetric mass transfer coefficient, K(L)a, the specific interfacial area, a, and the specific power input, P/V(L), were measured and compared. If a medium is used with a concentration of complex substrates (extracts) 2.5 times higher than that of glucose, a spectrum of C sources is available and cell regulation influences reactor performance. Both mu(m) and Y(X/S), which were evaluated in batch reactors, cannot be used for continuous reactors or, when measured in stirred-tank reactors, cannot be employed for tower-loop reactors: mu(m) is higher in the stirred-tank batch than in the tower-loop batch reactor, mu(m) and Y(x/s) are higher in the continuous reactor than in the batch single-stage tower-loop reactor. The performance of the single-stage is better than that of the ten-stage reactor due to the inefficient trays employed. A reduction of the medium recirculation rate reduces OTR, U(s), Pr, and Y(X/S) and causes cell sedimentation and flocculation. The volumetric mass transfer coefficient is reduced with increasing cultivation time; the Sauter bubble diameter, d(s), remains constant and does not depend on operational conditions. An increase in the medium recirculation rate reduces k(L)a. The specific power input, P/V(L), for the single-stage tower loop is much lower with the same k(L)a value than for a stirred tank. The relationship k(L)a vs. P/V(L) evaluated for model media in stirred tanks, can also be used for cultivations in these reactors.

Genetically engineered Escherichia coli FBR5: Part I. Comparison of high cell density bioreactors for enhanced ethanol production from xylose

USDA-ARS?s Scientific Manuscript database

Five reactor systems (free cell batch, free cell continuous, entrapped cell immobilized, adsorbed cell packed bed, and cell recycle membrane reactors) were compared for ethanol production from xylose employing Escherichia coli FBR5. In the free cell batch and free cell continuous reactors (continuo...

Production of edible carbohydrates from formaldehyde in a spacecraft. pH variations in the calcium hydroxide catalyzed formose reaction. Final Report, 1 Jul. 1973 - 30 Jun. 1974. M.S. Thesis

NASA Technical Reports Server (NTRS)

Weiss, A. H.; Kohler, J. T.; John, T.

1974-01-01

The study of the calcium hydroxide catalyzed condensation of formaldehyde was extended to a batch reactor system. Decreases in pH were observed, often in the acid regime, when using this basic catalyst. This observation was shown to be similar to results obtained by others using less basic catalysts in the batch mode. The relative rates of these reactions are different in a batch reactor than in a continuous stirred tank reactor. This difference in relative rates is due to the fact that at any degree of advancement in the batch system, the products have a history of previous products, pH, and dissolved catalyst. The relative rate differences can be expected to yield a different nature of product sugars for the two types of reactors.

Monochloramine Cometabolism by Mixed-Culture Nitrifiers under Drinking Water Conditions

EPA Science Inventory

The current research investigated monochloramine cometabolism by nitrifying mixed cultures grown under drinking water relevant conditions and harvested from sand-packed reactors before conducting suspended growth batch kinetic experiments. Three batch reactors were used in each ...

Comparison of heavy metal toxicity in continuous flow and batch reactors

NASA Astrophysics Data System (ADS)

Sengor, S. S.; Gikas, P.; Moberly, J. G.; Peyton, B. M.; Ginn, T. R.

2009-12-01

The presence of heavy metals may significantly affect microbial growth. In many cases, small amounts of particular heavy metals may stimulate microbial growth; however, larger quantities may result in microbial growth reduction. Environmental parameters, such as growth pattern may alter the critical heavy metal concentration, above which microbial growth stimulation turns to growth inhibition. Thus, it is important to quantify the effects of heavy metals on microbial activity for understanding natural or manmade biological reactors, either in situ or ex situ. Here we compare the toxicity of Zn and Cu on Arthrobacter sp., a heavy metal tolerant microorganism, under continuous flow versus batch reactor operations. Batch and continuous growth tests of Arthrobacter sp. were carried out at various individual and combined concentrations of Zn and Cu. Biomass concentration (OD) was measured for both the batch and continuous reactors, whereas ATP, oxygen uptake rates and substrate concentrations were additionally measured for the continuous system. Results indicated that Cu was more toxic than Zn under all conditions for both systems. In batch reactors, all tested Zn concentrations up to 150 uM showed a stimulatory effect on microbial growth. However, in the case of mixed Zn and Cu exposures, the presence of Zn either eliminated (at the 50 uM level both Zn and Cu) or reduced by ~25% (at the 100 and 150 uM levels both Zn and Cu) the Cu-induced inhibition. In the continuous system, only one test involved combined Cu (40uM) and Zn (125uM) and this test showed similar results to the 40uM Cu continuous test, i.e., no reduction in inhibition. The specific ATP concentration, i.e., ATP/OD, results for the continuous reactor showed an apparent recovery for both Cu-treated populations, although neither the OD nor glucose data showed any recovery. This may reflect that the individual microorganisms that survived after the addition of heavy metals, kept maintaining the usual ATP levels, as before metal addition. The last may imply a short of adaptation by some microorganisms to the presence of heavy metals. Overall, the batch reactor tests underestimated significantly the heavy metal inhibition, as compared to the continuous flow reactors. Therefore, the results of batch reactor tests should be used with some caution when heavy metal inhibition is to be interpreted for continuous flow natural environmental systems, such as rivers or wetlands.

Modeling Lab-sized Anaerobic Fluidized Bed Reactor (AFBR) for Palm Oil Mill Effluent (POME) treatment: from Batch to Continuous Reactors

NASA Astrophysics Data System (ADS)

Mufti Azis, Muhammad; Sudibyo, Hanifrahmawan; Budhijanto, Wiratni

2018-03-01

Indonesia is aiming to produce 30 million tones/year of crude palm oil (CPO) by 2020. As a result, 90 million tones/year of POME will be produced. POME is highly polluting wastewater which may cause severe environmental problem due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Due to the limitation of open pond treatment, the use of AFBR has been considered as a potential technology to treat POME. This study aims to develop mathematical models of lab-sized Anaerobic Fluidized Bed Reactor (AFBR) in batch and continuous processes. In addition, the AFBR also utilized natural zeolite as an immobilized media for microbes. To initiate the biomass growth, biodiesel waste has been used as an inoculum. In the first part of this study, a batch AFBR was operated to evaluate the COD, VFA, and CH4 concentrations. By comparing the batch results with and without zeolite, it showed that the addition of 17 g/gSCOD zeolite gave larger COD decrease within 20 days of operation. In order to elucidate the mechanism, parameter estimations of 12 kinetic parameters were proposed to describe the batch reactor performance. The model in general could describe the batch experimental data well. In the second part of this study, the kinetic parameters obtained from batch reactor were used to simulate the performance of double column AFBR where the acidogenic and methanogenic biomass were separated. The simulation showed that a relatively long residence time (Hydraulic Residence Time, HRT) was required to treat POME using the proposed double column AFBR. Sensitivity analyses was conducted and revealed that μm1 appeared to be the most sensitive parameter to reduce the HRT of double column AFBR.

Technical-economical analysis of selected decentralized technologies for municipal wastewater treatment in the city of Rome.

PubMed

Gavasci, Renato; Chiavola, Agostina; Spizzirri, Massimo

2010-01-01

Several wastewater treatment technologies were evaluated as alternative systems to the more traditional centralized continuous flow system to serve decentralized areas of the city of Rome (Italy). For instance, the following technologies were selected: (1) Constructed wetlands, (2) Membrane Biological Reactor, (3) Deep Shaft, (4) Sequencing Batch Reactor, and (5) Combined Filtration and UV-disinfection. Such systems were distinguished based on the limits they are potentially capable of accomplishing on the effluent. Consequently, the SBR and DS were grouped together for their capability to comply with the standards for the discharge into surface waters (according to the Italian D.Lgs. 152/06, Table 1, All. 5), whereas the MBR and tertiary system (Filtration+UVc-disinfection) were considered together as they should be able to allow effluent discharge into soil (according to the Italian D.Lgs. 152/06, Table 4, All. 5) and/or reuse (according to the Italian D.M. 185/03). Both groups of technologies were evaluated in comparison with the more common continuous flow treatment sequence consisting of a biological activated sludge tank followed by the secondary settlement, with final chlorination. CWs were studied separately as a solution for decentralized urban areas with limited population. After the analysis of the main technical features, an economical estimate was carried out taking into account the investment, operation and maintenance costs as a function of the plant's capacity. The analysis was based on real data provided by the Company who manages the entire water system of the City of Rome (Acea Ato 2 S.p.A.). A preliminary design of the treatment plants using some of the selected technologies was finally carried out.

Generation of OH Radical by Ultrasonic Irradiation in Batch and Circulatory Reactor

NASA Astrophysics Data System (ADS)

Fang, Yu; Shimizu, Sayaka; Yamamoto, Takuya; Komarov, Sergey

2018-03-01

Ultrasonic technology has been widely investigated in the past as one of the advance oxidation processes to treat wastewater, in this process acoustic cavitation causes generation of OH radical, which play a vital role in improving the treatment efficiency. In this study, OH radical formation rate was measured in batch and circulatory reactor by using Weissler reaction at various ultrasound output power. It is found that the generation rate in batch reactor is higher than that in circulatory reactor at the same output power. The generation rate tended to be slower when output power exceeds 137W. The optimum condition for circulatory reactor was found to be 137W output and 4L/min flow rate. Results of aluminum foil erosion test revealed a strong dependence of cavitation zone length on the ultrasound output power. This is assumed to be one of the reasons why the generation rate of HO radicals becomes slower at higher output power in circulatory reactor.

Design and fabrication of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolytic oil production in Bangladesh

NASA Astrophysics Data System (ADS)

Aziz, Mohammad Abdul; Al-khulaidi, Rami Ali; Rashid, MM; Islam, M. R.; Rashid, MAN

2017-03-01

In this research, a development and performance test of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolysis oil production was successfully completed. The characteristics of the pyrolysis oil were compared to other experimental results. A solid horizontal condenser, a burner for furnace heating and a reactor shield were designed. Due to the pilot scale pyrolytic oil production encountered numerous problems during the plant’s operation. This fixed-bed batch type pyrolysis reactor method will demonstrate the energy saving concept of solid waste tire by creating energy stability. From this experiment, product yields (wt. %) for liquid or pyrolytic oil were 49%, char 38.3 % and pyrolytic gas 12.7% with an operation running time of 185 minutes.

Fundamental understanding of the thermal degradation mechanisms of waste tires and their air pollutant generation in a N2 atmosphere.

PubMed

Kwon, Eilhann; Castaldi, Marco J

2009-08-01

The thermal decomposition of waste tires has been characterized via thermo-gravimetric analysis (TGA) tests, and significant mass loss has been observed between 300 and 500 degrees C. A series of gas chromatography-mass spectrometer (GC-MS) measurements, in which the instrument was coupled to a TGA unit, have been carried out to investigate the thermal degradation mechanisms as well as the air pollutant generation including volatile organic carbons (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in a nitrogen atmosphere. In order to understand fundamental information on the thermal degradation mechanisms of waste tires, the main constituents of tires, poly-isoprene rubber (IR) and styrene butadiene rubber (SBR), have been studied under the same conditions. All of the experimental work indicated that the bond scission on each monomer of the main constituents of tires was followed by hydrogenation and gas phase reactions. This helped to clarify the independent pathways and species attributable to IR and SBR during the pyrolysis process. To extend that understanding to a more practical level, a flow-through reactor was used to test waste tire, SBR and IR samples in the temperature range of 500-800 degrees C at a heating rate of approximately 200 degrees C. Lastly, the formation of VOCs (approximately 1-50 PPMV/10 mg of sample) and PAHs (approximately 0.2-7 PPMV/10 mg of sample) was observed at relatively low temperatures compared to conventional fuels, and its quantified concentration was significantly high due to the chemical structure of SBR and IR. The measurement of chemicals released during pyrolysis suggests not only a methodology for reducing the air pollutants but also the feasibility of petrochemical recovery during thermal treatment.

Evaluation of enzymatic reactors for large-scale panose production.

PubMed

Fernandes, Fabiano A N; Rodrigues, Sueli

2007-07-01

Panose is a trisaccharide constituted by a maltose molecule bonded to a glucose molecule by an alpha-1,6-glycosidic bond. This trisaccharide has potential to be used in the food industry as a noncariogenic sweetener, as the oral flora does not ferment it. Panose can also be considered prebiotic for stimulating the growth of benefic microorganisms, such as lactobacillus and bifidobacteria, and for inhibiting the growth of undesired microorganisms such as E. coli and Salmonella. In this paper, the production of panose by enzymatic synthesis in a batch and a fed-batch reactor was optimized using a mathematical model developed to simulate the process. Results show that optimum production is obtained in a fed-batch process with an optimum production of 11.23 g/l h of panose, which is 51.5% higher than production with batch reactor.

Occurrence and removal of endocrine-disrupting chemicals in wastewater treatment plants in the Three Gorges Reservoir area, Chongqing, China.

PubMed

Ye, Xin; Guo, Xuesong; Cui, Xing; Zhang, Xian; Zhang, Han; Wang, M K; Qiu, Ling; Chen, Shaohua

2012-08-01

Concentrations of six endocrine-disrupting compounds (EDCs), bisphenol A (BPA), estrone (E(1)), 17β-estradiol (E(2)), estriol (E(3)), 17α-ethynylestradiol (EE(2)) and diethylstilbestrol (DES), were assessed in influents, effluents and excess sludge in ten municipal wastewater treatment plants (WWTPs) in the Three Gorges Reservoir (TGR) area, Chongqing, China. Three types of activated sludge treatment processes, oxidation ditch (OD), reversed anaerobic-anoxic-oxic (rA(2)/O) technology and sequential batch reactor (SBR), were used in the surveyed WWTPs. These WWTPs were all combined landfill leachate-sewage treatment plants. All analytes were extracted by solid-phase extraction (SPE) in the dissolved phase and by accelerated solvent-based extraction (ASE) in sludge. Gas chromatography-mass spectrometry (GC-MS) was employed for the analysis of EDCs. Among these EDCs, BPA was the most frequently detected and abundant compound (100.0-10566.7 ng L(-1), 15.5-1210.7 ng L(-1) and 85.0-2470.4 ng g(-1) with respect to the influents, effluents and excess sludge samples). The greatest levels of steroidal estrogens in municipal influents were observed in E(3) which were all >100 ng L(-1), followed by E(1) (42.2-110.7 ng L(-1)) and E(2) (7.4-32.7 ng L(-1)), and in the effluents and sludge were E(1) > E(3) > E(2) which were all <31 ng L(-1) and 105 ng g(-1), respectively. Regarding synthetic estrogens, EE(2) was frequently detected in the influents, occurring below 50 ng L(-1), while DES was not detected at all. A high correlation coefficient was observed between the leachate-sludge ratio and concentrations of influent EDCs, and it was statistically significant (i.e., R > 0.65, P < 0.05), but removal efficiency of the EDCs did not show significant differences with OD, rA(2)/O and SBR processes. Furthermore, modification of treatment technology as well as operational parameters, such as hydraulic retention time (HRT), sludge retention time (SRT) and disinfection process (DP), were recommended to further eliminate the residual EDCs.

Production Methods in Industrial Microbiology.

ERIC Educational Resources Information Center

Gaden, Elmer L., Jr.

1981-01-01

Compares two methods (batch and continuous) in which microorganisms are used to produce industrial chemicals. Describes batch and continuous stirred-tank reactors and offers reasons why the batch method may be preferred. (JN)

The synthesis of cadmium sulfide nanoplatelets using a novel continuous flow sonochemical reactor

DOE PAGES

Palanisamy, Barath; Paul, Brian; Chang, Chih -hung

2015-01-21

A continuous flow sonochemical reactor was developed capable of producing metastable cadmium sulfide (CdS) nanoplatelets with thicknesses at or below 10 nm. The continuous flow sonochemical reactor included the passive in-line micromixing of reagents prior to sonochemical reaction. Synthesis results were compared with those from reactors involving batch conventional heating and batch ultrasound-induced heating. The continuous sonochemical synthesis was found to result in high aspect ratio hexagonal platelets of CdS possessing cubic crystal structures with thicknesses well below 10 nm. The unique shape and crystal structure of the nanoplatelets are suggestive of high localized temperatures within the sonochemical process. Asmore » a result, the particle size uniformity and product throughput are much higher for the continuous sonochemical process in comparison to the batch sonochemical process and conventional synthesis processes.« less

Anaerobic sequencing batch reactors for wastewater treatment: a developing technology.

PubMed

Zaiat, M; Rodrigues, J A; Ratusznei, S M; de Camargo, E F; Borzani, W

2001-01-01

This paper describes and discusses the main problems related to anaerobic batch and fed-batch processes for wastewater treatment. A critical analysis of the literature evaluated the industrial application viability and proposed alternatives to improve operation and control of this system. Two approaches were presented in order to make this anaerobic discontinuous process feasible for industrial application: (1) optimization of the operating procedures in reactors containing self-immobilized sludge as granules, and (2) design of bioreactors with inert support media for biomass immobilization.

Nitrogen removal in moving bed sequencing batch reactor using polyurethane foam cubes of various sizes as carrier materials.

PubMed

Lim, Jun-Wei; Seng, Chye-Eng; Lim, Poh-Eng; Ng, Si-Ling; Sujari, Amat-Ngilmi Ahmad

2011-11-01

The performance of moving bed sequencing batch reactors (MBSBRs) added with 8 % (v/v) of polyurethane (PU) foam cubes as carrier media in nitrogen removal was investigated in treating low COD/N wastewater. The results indicate that MBSBR with 8-mL cubes achieved the highest total nitrogen (TN) removal efficiency of 37% during the aeration period, followed by 31%, 24% and 19 % for MBSBRs with 27-, 64- and 125-mL cubes, respectively. The increased TN removal in MBSBRs was mainly due to simultaneous nitrification and denitrification (SND) process which was verified by batch studies. The relatively lower TN removal in MBSBR with larger PU foam cubes was attributed to the observation that larger PU foam cubes were not fully attached by biomass. Higher concentrations of 8-mL PU foam cubes in batch reactors yielded higher TN removal. Copyright © 2011 Elsevier Ltd. All rights reserved.

High Solid Fed-batch Butanol Fermentation with Simultaneous Product Recovery: Part II - Process Integration.

PubMed

Qureshi, Nasib; Klasson, K Thomas; Saha, Badal C; Liu, Siqing

2018-04-25

In these studies liquid hot water (LHW) pretreated and enzymatically hydrolyzed Sweet Sorghum Bagasse (SSB) hydrolyzates were fermented in a fed-batch reactor. As reported in the preceding paper, the culture was not able to ferment the hydrolyzate I in a batch process due to presence of high level of toxic chemicals, in particular acetic acid released from SSB during the hydrolytic process. To be able to ferment the hydrolyzate I obtained from 250 gL -1 SSB hydrolysis, a fed-batch reactor with in-situ butanol recovery was devised. The process was started with the hydrolyzate II and when good cell growth and vigorous fermentation were observed, the hydrolyzate I was slowly fed to the reactor. In this manner the culture was able to ferment all the sugars present in both the hydrolyzates to acetone butanol ethanol (ABE). In a control batch reactor in which ABE was produced from glucose, ABE productivity and yield of 0.42 gL -1 h -1 and 0.36 were obtained, respectively. In the fed-batch reactor fed with SSB hydrolyzates these productivity and yield values were 0.44 gL -1 h -1 and 0.45, respectively. ABE yield in the integrated system was high due to utilization of acetic acid to convert to ABE. In summary we were able to utilize both the hydrolyzates obtained from LHW pretreated and enzymatically hydrolyzed SSB (250 gL -1 ) and convert them to ABE. Complete fermentation was possible due to simultaneous recovery of ABE by vacuum. This article is protected by copyright. All rights reserved. © 2018 American Institute of Chemical Engineers.

Fossil fuel furnace reactor

DOEpatents

Parkinson, William J.

1987-01-01

A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

Cure kinetics, morphologies, and mechanical properties of thermoplastic/MWCNT modified multifunctional glassy epoxies prepared via continuous reaction methods

NASA Astrophysics Data System (ADS)

Cheng, Xiaole

The primary goal of this dissertation is to develop a novel continuous reactor method to prepare partially cured epoxy prepolymers for aerospace prepreg applications with the aim of replacing traditional batch reactors. Compared to batch reactors, the continuous reactor is capable of solubilizing and dispersing a broad range of additives including thermoplastic tougheners, stabilizers, nanoparticles and curatives and advancing epoxy molecular weights and viscosities while reducing energy consumption. In order to prove this concept, polyethersulfone (PES) modified 4, 4'-diaminodiphenylsulfone (44DDS)/tetraglycidyl-4, 4'-diaminodiphenylmethane (TGDDM) epoxy prepolymers were firstly prepared using both continuous reactor and batch reactor methods. Kinetic studies confirmed the chain extension reaction in the continuous reactor is similar to the batch reactor, and the molecular weights and viscosities of prepolymers were readily controlled through reaction kinetics. Atomic force microscopy (AFM) confirmed similar cured network morphologies for formulations prepared from batch and continuous reactors. Additionally tensile strength, tensile modulus and fracture toughness analyses concluded mechanical properties of cured epoxy matrices produced from both reactors were equivalent. Effects of multifunctional epoxy compositions on thermoplastics phase-separated morphologies were systematically studied using a combination of AFM with nanomechanical mapping, spectroscopic and calorimetric techniques to provide new insights to tailor cured reaction induced phase separation (CRIPS) in multifunctional epoxy blend networks. Furthermore, how resultant crosslinked glassy polymer network and phase-separated morphologies correlated with mechanical properties are discussed in detail. Multiwall carbon nanotube (MWCNT)/TGDDM epoxy prepolymers were further prepared by combining the successful strategies for advancing epoxy chemistries and dispersing nanotubes using the continuous reactor. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the MWCNT dispersion states and stabilization in epoxy prepolymer matrix after continuous process and during curing cycles. Additionally, electrical conductivities and mechanical properties of final cured MWCNT/TGDDM composites were measured and discussed in view of their corresponding MWCNT dispersion states. Ternary blends of MWCNT reinforced thermoplastic/epoxy prepolymers were prepared by the continuous reactor. Influence of MWCNT on the CRIPS mechanism and the cured morphologies were systematically investigated using SEM and rheological analysis. Incorporation of MWCNT in thermoplastic/epoxy matrices can lead to a morphological transformation from phase inverted, to co-continuous, and to droplet dispersed morphology. In additional, dynamic mechanical analysis revealed the heterogeneity of MWCNT dispersion in thermoplastic/thermosets systems.

Integrated continuous dissolution, refolding and tag removal of fusion proteins from inclusion bodies in a tubular reactor.

PubMed

Pan, Siqi; Zelger, Monika; Jungbauer, Alois; Hahn, Rainer

2014-09-20

An integrated continuous tubular reactor system was developed for processing an autoprotease expressed as inclusion bodies. The inclusion bodies were suspended and fed into the tubular reactor system for continuous dissolving, refolding and precipitation. During refolding, the dissolved autoprotease cleaves itself, separating the fusion tag from the target peptide. Subsequently, the cleaved fusion tag and any uncleaved autoprotease were precipitated out in the precipitation step. The processed exiting solution results in the purified soluble target peptide. Refolding and precipitation yields performed in the tubular reactor were similar to batch reactor and process was stable for at least 20 h. The authenticity of purified peptide was also verified by mass spectroscopy. Productivity (in mg/l/h and mg/h) calculated in the tubular process was twice and 1.5 times of the batch process, respectively. Although it is more complex to setup a tubular than a batch reactor, it offers faster mixing, higher productivity and better integration to other bioprocessing steps. With increasing interest of integrated continuous biomanufacturing, the use of tubular reactors in industrial settings offers clear advantages. Copyright © 2014 Elsevier B.V. All rights reserved.

Prediction of acid hydrolysis of lignocellulosic materials in batch and plug flow reactors.

PubMed

Jaramillo, Oscar Johnny; Gómez-García, Miguel Ángel; Fontalvo, Javier

2013-08-01

This study unifies contradictory conclusions reported in literature on acid hydrolysis of lignocellulosic materials, using batch and plug flow reactors, regarding the influence of the initial liquid ratio of acid aqueous solution to solid lignocellulosic material on sugar yield and concentration. The proposed model takes into account the volume change of the reaction media during the hydrolysis process. An error lower than 8% was found between predictions, using a single set of kinetic parameters for several liquid to solid ratios, and reported experimental data for batch and plug flow reactors. For low liquid-solid ratios, the poor wetting and the acid neutralization, due to the ash presented in the solid, will both reduce the sugar yield. Also, this study shows that both reactors are basically equivalent in terms of the influence of the liquid to solid ratio on xylose and glucose yield. Copyright © 2013 Elsevier Ltd. All rights reserved.

A KINETIC MODEL FOR H2O2/UV PROCESS IN A COMPLETELY MIXED BATCH REACTOR. (R825370C076)

EPA Science Inventory

A dynamic kinetic model for the advanced oxidation process (AOP) using hydrogen peroxide and ultraviolet irradiation (H₂O₂/UV) in a completely mixed batch reactor (CMBR) is developed. The model includes the known elementary chemical and photochemical reac...

Continuous Heterogeneous Photocatalysis in Serial Micro-Batch Reactors.

PubMed

Pieber, Bartholomäus; Shalom, Menny; Antonietti, Markus; Seeberger, Peter H; Gilmore, Kerry

2018-01-29

Solid reagents, leaching catalysts, and heterogeneous photocatalysts are commonly employed in batch processes but are ill-suited for continuous-flow chemistry. Heterogeneous catalysts for thermal reactions are typically used in packed-bed reactors, which cannot be penetrated by light and thus are not suitable for photocatalytic reactions involving solids. We demonstrate that serial micro-batch reactors (SMBRs) allow for the continuous utilization of solid materials together with liquids and gases in flow. This technology was utilized to develop selective and efficient fluorination reactions using a modified graphitic carbon nitride heterogeneous catalyst instead of costly homogeneous metal polypyridyl complexes. The merger of this inexpensive, recyclable catalyst and the SMBR approach enables sustainable and scalable photocatalysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanocrystal synthesis in microfluidic reactors: where next?

PubMed

Phillips, Thomas W; Lignos, Ioannis G; Maceiczyk, Richard M; deMello, Andrew J; deMello, John C

2014-09-07

The past decade has seen a steady rise in the use of microfluidic reactors for nanocrystal synthesis, with numerous studies reporting improved reaction control relative to conventional batch chemistry. However, flow synthesis procedures continue to lag behind batch methods in terms of chemical sophistication and the range of accessible materials, with most reports having involved simple one- or two-step chemical procedures directly adapted from proven batch protocols. Here we examine the current status of microscale methods for nanocrystal synthesis, and consider what role microreactors might ultimately play in laboratory-scale research and industrial production.

Demonstration of Robustness and Integrated Operation of a Series-Bosch System

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Mansell, Matthew J.; Stanley, Christine; Barnett, Bill; Junaedi, Christian; Vilekar, Saurabh A.; Ryan, Kent

2016-01-01

Manned missions beyond low Earth orbit will require highly robust, reliable, and maintainable life support systems that maximize recycling of water and oxygen. Bosch technology is one option to maximize oxygen recovery, in the form of water, from metabolically-produced carbon dioxide (CO2). A two stage approach to Bosch, called Series-Bosch, reduces metabolic CO2 with hydrogen (H2) to produce water and solid carbon using two reactors: a Reverse Water-Gas Shift (RWGS) reactor and a carbon formation (CF) reactor. Previous development efforts demonstrated the stand-alone performance of a NASA-designed RWGS reactor designed for robustness against carbon formation, two membrane separators intended to maximize single pass conversion of reactants, and a batch CF reactor with both transit and surface catalysts. In the past year, Precision Combustion, Inc. (PCI) developed and delivered a RWGS reactor for testing at NASA. The reactor design was based on their patented Microlith® technology and was first evaluated under a Phase I Small Business Innovative Research (SBIR) effort in 2010. The RWGS reactor was recently evaluated at NASA to compare its performance and operating conditions with NASA's RWGS reactor. The test results will be provided in this paper. Separately, in 2015, a semi-continuous CF reactor was designed and fabricated at NASA based on the results from batch CF reactor testing. The batch CF reactor and the semi-continuous CF reactor were individually integrated with an upstream RWGS reactor to demonstrate the system operation and to evaluate performance. Here, we compare the performance and robustness to carbon formation of both RWGS reactors. We report the results of the integrated operation of a Series-Bosch system and we discuss the technology readiness level.

Fuel Cycle Performance of Thermal Spectrum Small Modular Reactors

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

Worrall, Andrew; Todosow, Michael

2016-01-01

Small modular reactors may offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of small modular reactors on the nuclear fuel cycle and fuel cycle performance. The focus of this paper is on the fuel cycle impacts of light water small modular reactors in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy Office of Nuclear Energy Fuel Cycle Options Campaign. Challenges with small modular reactors include:more » increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burn-up in the reactor and the fuel cycle performance. This paper summarizes the results of an expert elicitation focused on developing a list of the factors relevant to small modular reactor fuel, core, and operation that will impact fuel cycle performance. Preliminary scoping analyses were performed using a regulatory-grade reactor core simulator. The hypothetical light water small modular reactor considered in these preliminary scoping studies is a cartridge type one-batch core with 4.9% enrichment. Some core parameters, such as the size of the reactor and general assembly layout, are similar to an example small modular reactor concept from industry. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burn-up of the reactor. Fuel cycle performance metrics for a small modular reactor are compared to a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. Metrics performance for a small modular reactor are degraded for mass of spent nuclear fuel and high level waste disposed, mass of depleted uranium disposed, land use per energy generated, and carbon emission per energy generated« less

A study on using fireclay as a biomass carrier in an activated sludge system.

PubMed

Tilaki, Ramazan Ali Dianati

2011-01-01

By adding a biomass carrier to an activated sludge system, the biomass concentration will increase, and subsequently the organic removal efficiency will be enhanced. In this study, the possibility of using excess sludge from ceramic and tile manufacturing plants as a biomass carrier was investigated. The aim of this study was to determine the effect of using fireclay as a biomass carrier on biomass concentration, organic removal and nitrification efficiency in an activated sludge system. Experiments were conducted by using a bench scale activated sludge system operating in batch and continuous modes. Artificial simulated wastewater was made by using recirculated water in a ceramic manufacturing plant. In the continuous mode, hydraulic detention time in the aeration reactor was 8 and 22 h. In the batch mode, aeration time was 8 and 16 h. Fireclay doses were 500, 1,400 and 2,250 mg l(-1), and were added to the reactors in each experiment separately. The reactor with added fireclay was called a Hybrid Biological Reactor (HBR). A reactor without added fireclay was used as a control. Efficiency parameters such as COD, MLVSS and nitrate were measured in the control and HBR reactors according to standard methods. The average concentration of biomass in the HBR reactor was greater than in the control reactor. The total biomass concentration in the HBR reactor (2.25 g l(-1) fireclay) in the continuous mode was 3,000 mg l(-1) and in the batch mode was 2,400 mg l(-1). The attached biomass concentration in the HBR reactor (2.25 g l(-1) fireclay) in the continuous mode was 1,500 mg l(-1) and in the batch mode was 980 mg l(-1). Efficiency for COD removal in the HBR and control reactor was 95 and 55%, respectively. In the HBR reactor, nitrification was enhanced, and the concentration of nitrate was increased by 80%. By increasing the fireclay dose, total and attached biomass was increased. By adding fireclay as a biomass carrier, the efficiency of an activated sludge system to treat wastewater from ceramic manufacturing plants was increased.

RF Systems in Space. Volume I. Space Antennas Frequency (SARF) Simulation.

DTIC Science & Technology

1983-04-01

lens SBR designs were investigated. The survivability of an SBR system was analyzed. The design of ground based SBR validation experiments for large...aperture SBR concepts were investigated. SBR designs were investigated for ground target detection. N1’IS GRAMI DTIC TAB E Unannounced E Justificat... designs :~~.~...: .-..:. ->.. - . *.* . ..- . . .. . -. . ..- . .4. To analyze the survivability of space radar 5. To design ground-based validation

A molecular dynamics study on Young's modulus and tribology of carbon nanotube reinforced styrene-butadiene rubber.

PubMed

Chawla, Raj; Sharma, Sumit

2018-03-18

Styrene-butadiene rubber is a copolymer widely used in making car tires and has excellent abrasion resistance. The Young's modulus and tribology of pure styrene butadiene rubber (SBR) polymer and carbon nanotube reinforced polymer composites have been investigated using molecular dynamics simulations. The mechanism of enhanced tribology properties using carbon nanotube has been studied and discussed. The obtained Young's modulus shows the enhancement in mechanical properties of SBR polymer when carbon nanotubes are used as reinforcement. The concentration, temperature and velocity profiles, radial distribution function, frictional stresses, and cohesive energy density are calculated and analyzed in detail. The Young's modulus of SBR matrix increases about 29.16% in the presence of the 5% CNT. The atom movement velocity and average cohesive energy density in the friction area of pure SBR matrix was found to be more than that of the CNT/SBR composite. Graphical abstract Initial and final conditions of (a) pure SBR matrix and (b) CNT/SBR matrix subjected toshear loading and frictional stresses of top Fe layers of both pure SBR and CNT/SBR composite.

Elimination of water pathogens with solar radiation using an automated sequential batch CPC reactor.

PubMed

Polo-López, M I; Fernández-Ibáñez, P; Ubomba-Jaswa, E; Navntoft, C; García-Fernández, I; Dunlop, P S M; Schmid, M; Byrne, J A; McGuigan, K G

2011-11-30

Solar disinfection (SODIS) of water is a well-known, effective treatment process which is practiced at household level in many developing countries. However, this process is limited by the small volume treated and there is no indication of treatment efficacy for the user. Low cost glass tube reactors, together with compound parabolic collector (CPC) technology, have been shown to significantly increase the efficiency of solar disinfection. However, these reactors still require user input to control each batch SODIS process and there is no feedback that the process is complete. Automatic operation of the batch SODIS process, controlled by UVA-radiation sensors, can provide information on the status of the process, can ensure the required UVA dose to achieve complete disinfection is received and reduces user work-load through automatic sequential batch processing. In this work, an enhanced CPC photo-reactor with a concentration factor of 1.89 was developed. The apparatus was automated to achieve exposure to a pre-determined UVA dose. Treated water was automatically dispensed into a reservoir tank. The reactor was tested using Escherichia coli as a model pathogen in natural well water. A 6-log inactivation of E. coli was achieved following exposure to the minimum uninterrupted lethal UVA dose. The enhanced reactor decreased the exposure time required to achieve the lethal UVA dose, in comparison to a CPC system with a concentration factor of 1.0. Doubling the lethal UVA dose prevented the need for a period of post-exposure dark inactivation and reduced the overall treatment time. Using this reactor, SODIS can be automatically carried out at an affordable cost, with reduced exposure time and minimal user input. Copyright © 2011 Elsevier B.V. All rights reserved.

Low-temperature catalytic gasification of food processing wastes. 1995 topical report

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

Elliott, D.C.; Hart, T.R.

The catalytic gasification system described in this report has undergone continuing development and refining work at Pacific Northwest National Laboratory (PNNL) for over 16 years. The original experiments, performed for the Gas Research Institute, were aimed at developing kinetics information for steam gasification of biomass in the presence of catalysts. From the fundamental research evolved the concept of a pressurized, catalytic gasification system for converting wet biomass feedstocks to fuel gas. Extensive batch reactor testing and limited continuous stirred-tank reactor tests provided useful design information for evaluating the preliminary economics of the process. This report is a follow-on to previousmore » interim reports which reviewed the results of the studies conducted with batch and continuous-feed reactor systems from 1989 to 1994, including much work with food processing wastes. The discussion here provides details of experiments on food processing waste feedstock materials, exclusively, that were conducted in batch and continuous- flow reactors.« less

Laboratory-scale anaerobic sequencing batch reactor for treatment of stillage from fruit distillation.

PubMed

Rada, Elena Cristina; Ragazzi, Marco; Torretta, Vincenzo

2013-01-01

This work describes batch anaerobic digestion tests carried out on stillages, the residue of the distillation process on fruit, in order to contribute to the setting of design parameters for a planned plant. The experimental apparatus was characterized by three reactors, each with a useful volume of 5 L. The different phases of the work carried out were: determining the basic components of the chemical oxygen demand (COD) of the stillages; determining the specific production of biogas; and estimating the rapidly biodegradable COD contained in the stillages. In particular, the main goal of the anaerobic digestion tests on stillages was to measure the parameters of specific gas production (SGP) and gas production rate (GPR) in reactors in which stillages were being digested using ASBR (anaerobic sequencing batch reactor) technology. Runs were developed with increasing concentrations of the feed. The optimal loads for obtaining the maximum SGP and GPR values were 8-9 gCOD L(-1) and 0.9 gCOD g(-1) volatile solids.

High-solid mesophilic methane fermentation of food waste with an emphasis on Iron, Cobalt, and Nickel requirements.

PubMed

Qiang, Hong; Lang, Dong-Li; Li, Yu-You

2012-01-01

The effect of trace metals on the mesophilic methane fermentation of high-solid food waste was investigated using both batch and continuous experiments. The continuous experiment was conducted by using a CSTR-type reactor with three run. During the first run, the HRT of the reactor was stepwise decreased from 100 days to 30 days. From operation day 50, the reactor efficiency deteriorated due to the lack of trace metals. The batch experiment showed that iron, cobalt, and nickel combinations had a significant effect on food waste. According to the results of the batch experiment, a combination of iron, cobalt, and nickel was added into the CSTR reactor by two different methods at run II, and III. Based on experimental results and theoretical calculations, the most suitable values of Fe/COD, Co/COD, and Ni/COD in the substrate were identified as 200, 6.0, and 5.7 mg/kg COD, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparison of Reductive Dechlorination of Chlorinated Ethylene in Batch and Continuous-Flow Reactor

NASA Astrophysics Data System (ADS)

Park, S.; Jonghwan, L.; Hong, U.; Kim, N.; Ahn, H.; Lee, S.; Kim, Y.

2010-12-01

A 1.28 L-Batch reactor and continuous-flow stirred tank reactor (CFSTR) fed with formate and trichloriethene (TCE) were operated for 120 days and 72 days, respectively, to study the effect of formate as electron donor on reductive dechlorination of TCE to cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene (ETH). In batch reactor, injected 60 μmol TCE was completely degraded in presence of 20% hydrogen gas (H2) in less than 8 days by Evanite culture (300 mg-soluble protein) with ability to completely degrade tetrachloroethene (PCE) and TCE to ETH under anaerobic conditions. To determine the effect of formate as electron donor instead of H2, about 3 or 11 mmol of formate injected into batch-reactor every 15 days was enough to support H2 for dechlorination of c-DCE to VC and ETH. Soluble protein concentration of Evanite culture during the batch test increased from 300 mg to 688 mg for 120 days. In CFSTR test, TCE was fed continuously at 9.9 ppm (75.38 μmol/L) and the influent formate feed concentration increased stepwise from 1.3 mmol/L to 14.3 mmol/L. Injected TCE was accumulated at HRT 18 days for 13 days, but TCE was completed degraded at HRT 36 days without accumulation during left of experiment period, getting H2 from fermentative hydrogen production of injected formate. Although c-DCE was also accumulated for 23 days after CFSTR operation, it reached steady-state without accumulation in presence of excessive formate. However, since c-DCE in CFSTR was not completely dechlorinated, we will determine the transcriptional level of enzyme involved in reductive dechlorination of TCE, c-DCE, and VC in our future work.

Simultaneous biodegradation of three mononitrophenol isomers by a tailor-made microbial consortium immobilized in sequential batch reactors.

PubMed

Fu, H; Zhang, J-J; Xu, Y; Chao, H-J; Zhou, N-Y

2017-03-01

The ortho-nitrophenol (ONP)-utilizing Alcaligenes sp. strain NyZ215, meta-nitrophenol (MNP)-utilizing Cupriavidus necator JMP134 and para-nitrophenol (PNP)-utilizing Pseudomonas sp. strain WBC-3 were assembled as a consortium to degrade three nitrophenol isomers in sequential batch reactors. Pilot test was conducted in flasks to demonstrate that a mixture of three mononitrophenols at 0·5 mol l -1 each could be mineralized by this microbial consortium within 84 h. Interestingly, neither ONP nor MNP was degraded until PNP was almost consumed by strain WBC-3. By immobilizing this consortium into polyurethane cubes, all three mononitrophenols were continuously degraded in lab-scale sequential reactors for six batch cycles over 18 days. Total concentrations of ONP, MMP and PNP that were degraded were 2·8, 1·5 and 2·3 mol l -1 during this time course respectively. Quantitative real-time PCR analysis showed that each member in the microbial consortium was relatively stable during the entire degradation process. This study provides a novel approach to treat polluted water, particularly with a mixture of co-existing isomers. Nitroaromatic compounds are readily spread in the environment and pose great potential toxicity concerns. Here, we report the simultaneous degradation of three isomers of mononitrophenol in a single system by employing a consortium of three bacteria, both in flasks and lab-scale sequential batch reactors. The results demonstrate that simultaneous biodegradation of three mononitrophenol isomers can be achieved by a tailor-made microbial consortium immobilized in sequential batch reactors, providing a pilot study for a novel approach for the bioremediation of mixed pollutants, especially isomers present in wastewater. © 2016 The Society for Applied Microbiology.

Effect of xylan and lignin removal by batch and flowthrough pretreatment on the enzymatic digestibility of corn stover cellulose.

PubMed

Yang, Bin; Wyman, Charles E

2004-04-05

Compared with batch systems, flowthrough and countercurrent reactors have important potential advantages for pretreating cellulosic biomass, including higher hemicellulose sugar yields, enhanced cellulose digestibility, and reduced chemical additions. Unfortunately, they suffer from high water and energy use. To better understand these trade-offs, comparative data are reported on xylan and lignin removal and enzymatic digestibility of cellulose for corn stover pretreated in batch and flowthrough reactors over a range of flow rates between 160 degrees and 220 degrees C, with water only and also with 0.1 wt% sulfuric acid. Increasing flow with just water enhanced the xylan dissolution rate, more than doubled total lignin removal, and increased cellulose digestibility. Furthermore, adding dilute sulfuric acid increased the rate of xylan removal for both batch and flowthrough systems. Interestingly, adding acid also increased the lignin removal rate with flow, but less lignin was left in solution when acid was added in batch. Although the enzymatic hydrolysis of pretreated cellulose was related to xylan removal, as others have shown, the digestibility was much better for flowthrough compared with batch systems, for the same degree of xylan removal. Cellulose digestibility for flowthrough reactors was related to lignin removal as well. These results suggest that altering lignin also affects the enzymatic digestibility of corn stover. Copyright 2004 Wiley Periodicals, Inc.

Progressing batch hydrolysis process

DOEpatents

Wright, J.D.

1985-01-10

A progressive batch hydrolysis process is disclosed for producing sugar from a lignocellulosic feedstock. It comprises passing a stream of dilute acid serially through a plurality of percolation hydrolysis reactors charged with feed stock, at a flow rate, temperature and pressure sufficient to substantially convert all the cellulose component of the feed stock to glucose. The cooled dilute acid stream containing glucose, after exiting the last percolation hydrolysis reactor, serially fed through a plurality of pre-hydrolysis percolation reactors, charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the hemicellulose component of said feedstock to glucose. The dilute acid stream containing glucose is cooled after it exits the last prehydrolysis reactor.

Progressing batch hydrolysis process

DOEpatents

Wright, John D.

1986-01-01

A progressive batch hydrolysis process for producing sugar from a lignocellulosic feedstock, comprising passing a stream of dilute acid serially through a plurality of percolation hydrolysis reactors charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the cellulose component of the feedstock to glucose; cooling said dilute acid stream containing glucose, after exiting the last percolation hydrolysis reactor, then feeding said dilute acid stream serially through a plurality of prehydrolysis percolation reactors, charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the hemicellulose component of said feedstock to glucose; and cooling the dilute acid stream containing glucose after it exits the last prehydrolysis reactor.

[Effects of carbon sources changes on the property and morphology of 2,4-D degraded aerobic sludge granules].

PubMed

Ma, Jing-Yun; Quan, Xian-Chun; Xiong, Wei-Cong

2010-11-01

This study investigated the changes of the morphology, structure, and capability of removing the target contamination of the aerobic granules pre-cultured with mixed substrates of glucose and 2,4-dichlorophenoxyacetic acid (2,4-D) in a long-time running sequence batch reactor (SBR), when the carbon source transformed into the sole carbon source of 2,4-D. Results showed that when the substrate turned to the sole carbon source of 2,4-D, the aerobic granules still maintained a strong degradation ability to the target contamination; a 2,4-D removal percentage of 99.2% -100% and an average COD removal rate of 85.6% were achieved at the initial 2,4-D concentration of 361-564 mg/L. Carbon source transformation caused certain damages to the original aerobic granule structure, made some parts of granules disintegrated, and led to granule size decline from 513 microm to 302 microm. However, those granules maintained the main body, re-aggregated and grew after a period of adaptation due to their strong resistance to toxicity. Aerobic granules capable of utilizing 2,4-D as the sole carbon source with a good settling ability (SYI 20-40 mL/g) and a mean diameter of 489 microm were finally obtained in this study. Scanning electron microscope (SEM) observation showed that the diversity of granule microbial species was declined when turned to the sole carbon source.

Component and System Sensitivity Considerations for Design of a Lunar ISRU Oxygen Production Plant

NASA Technical Reports Server (NTRS)

Linne, Diane L.; Gokoglu, Suleyman; Hegde, Uday G.; Balasubramaniam, Ramaswamy; Santiago-Maldonado, Edgardo

2009-01-01

Component and system sensitivities of some design parameters of ISRU system components are analyzed. The differences between terrestrial and lunar excavation are discussed, and a qualitative comparison of large and small excavators is started. The effect of excavator size on the size of the ISRU plant's regolith hoppers is presented. Optimum operating conditions of both hydrogen and carbothermal reduction reactors are explored using recently developed analytical models. Design parameters such as batch size, conversion fraction, and maximum particle size are considered for a hydrogen reduction reactor while batch size, conversion fraction, number of melt zones, and methane flow rate are considered for a carbothermal reduction reactor. For both reactor types the effect of reactor operation on system energy and regolith delivery requirements is presented.

The impact of microfluidic mixing of triblock micelleplexes on in vitro / in vivo gene silencing and intracellular trafficking

NASA Astrophysics Data System (ADS)

Feldmann, Daniel P.; Xie, Yuran; Jones, Steven K.; Yu, Dongyue; Moszczynska, Anna; Merkel, Olivia M.

2017-06-01

The triblock copolymer polyethylenimine-polycaprolactone-polyethylene glycol (PEI-PCL-PEG) has been shown to spontaneously assemble into nano-sized particulate carriers capable of complexing with nucleic acids for gene delivery. The objective of this study was to investigate micelleplex characteristics, their in vitro and in vivo fate following microfluidic preparation of siRNA nanoparticles compared to the routinely used batch reactor mixing technique. Herein, PEI-PCL-PEG nanoparticles were prepared with batch reactor or microfluidic mixing techniques and characterized by various biochemical assays and in cell culture. Microfluidic nanoparticles showed a reduction of overall particle size as well as a more uniform size distribution when compared to batch reactor pipette mixing. Confocal microscopy, flow cytometry and qRT-PCR displayed the subcellular delivery of the microfluidic formulation and confirmed the ability to achieve mRNA knockdown. Intratracheal instillation of microfluidic formulation resulted in a significantly more efficient (p < 0.05) knockdown of GAPDH compared to treatment with the batch reactor formulation. The use of microfluidic mixing techniques yields an overall smaller and more uniform PEG-PCL-PEI nanoparticle that is able to more efficiently deliver siRNA in vivo. This preparation method may prove to be useful when a scaled up production of well-defined polyplexes is required.

Ultrasound pretreatment for enhanced biogas production from olive mill wastewater.

PubMed

Oz, Nilgun Ayman; Uzun, Alev Cagla

2015-01-01

This study investigates applicability of low frequency ultrasound technology to olive mill wastewaters (OMWs) as a pretreatment step prior to anaerobic batch reactors to improve biogas production and methane yield. OMWs originating from three phase processes are characterized with high organic content and complex nature. The treatment of the wastewater is problematic and alternative treatment options should be investigated. In the first part of the study, OMW samples were subjected to ultrasound at a frequency of 20kHz with applied powers varying between 50 and 100W under temperature controlled conditions for different time periods in order to determine the most effective sonication conditions. The level of organic matter solubilization at ultrasound experiments was assessed by calculating the ratio of soluble chemical oxygen demand/total chemical oxygen demand (SCOD/TCOD). The results revealed that the optimum ultrasonic condition for diluted OMW is 20kHz, 0.4W/mL for 10min. The application of ultrasound to OMW increased SCOD/TCOD ratio from 0.59 to 0.79. Statistical analysis (Friedman's tests) show that ultrasound was significantly effective on diluted OMW (p<0.05) in terms of SCOD parameter, but not for raw OMW (p>0.05). For raw OMW, this increase has been found to be limited due to high concentration of suspended solids (SS). In the second part of the study, biogas and methane production rates of anaerobic batch reactor fed with the ultrasound pretreated OMW samples were compared with the results of control reactor fed with untreated OMW in order to determine the effect of sonication. A nonparametric statistical procedure, Mann-Whitney U test, was used to compare biogas and methane production from anaerobic batch reactors for control and ultrasound pretreated samples. Results showed that application of low frequency ultrasound to OMW significantly improved both biogas and methane production in anaerobic batch reactor fed with the wastewater (p<0.05). Anaerobic batch reactor fed with ultrasound pretreated diluted OMW produced approximately 20% more biogas and methane compared with the untreated one (control reactor). The overall results indicated that low frequency ultrasound pretreatment increased soluble COD in OMW and subsequently biogas production. Copyright © 2014 Elsevier B.V. All rights reserved.

Electrochemical study of multi-electrode microbial fuel cells under fed-batch and continuous flow conditions

NASA Astrophysics Data System (ADS)

Ren, Lijiao; Ahn, Yongtae; Hou, Huijie; Zhang, Fang; Logan, Bruce E.

2014-07-01

Power production of four hydraulically connected microbial fuel cells (MFCs) was compared with the reactors operated using individual electrical circuits (individual), and when four anodes were wired together and connected to four cathodes all wired together (combined), in fed-batch or continuous flow conditions. Power production under these different conditions could not be made based on a single resistance, but instead required polarization tests to assess individual performance relative to the combined MFCs. Based on the power curves, power produced by the combined MFCs (2.12 ± 0.03 mW, 200 Ω) was the same as the summed power (2.13 mW, 50 Ω) produced by the four individual reactors in fed-batch mode. With continuous flow through the four MFCs, the maximum power (0.59 ± 0.01 mW) produced by the combined MFCs was slightly lower than the summed maximum power of the four individual reactors (0.68 ± 0.02 mW). There was a small parasitic current flow from adjacent anodes and cathodes, but overall performance was relatively unaffected. These findings demonstrate that optimal power production by reactors hydraulically and electrically connected can be predicted from performance by individual reactors.

Effects of supplemental L-arginine on the intestinal adaptive response after massive small-bowel resection in rats.

PubMed

Oztürk, Hayrettin; Dokucu, Ali Ihsan; Yağmur, Yusuf; Sari, Ibrahim

2002-09-01

To evaluate whether L-arginine methyl ester (L-Arg) can improve the structure of the small intestine and enhance adaptation in an experimental model of short-bowel syndrome (SBS), 40 Sprague-Dawley rats were divided randomly into four groups of 10 each. In one group only a laparotomy was performed (G1). The remaining 30 rats underwent 90% small-bowel resection (SBR) and formed the three experimental groups: the SBR/untreated group (G2), the SBR/L-NAME-treated group (G3), and the SBR/ L-Arg-treated group (G4). Rats in G2 received no therapeutic treatment. Rats in the SBR/L-NAME and SBR/L-Arg treated groups received N-G-nitro-L-arginine-methyl ester (L-NAME) and L-Arg intraperitoneally for 3 weeks, respectively. The animals were weighed daily. All rats underwent a relaparotomy on day 21 of the experiment. Remnant small bowel was excised and evaluated for villus height and crypt cell mitoses. After the 90% SBR, all animals had from diarrhea and weight loss between the 1st and 6th postoperative days (POD). The body weight of the SBR/L-Arg group showed significant increases at POD 10 and 21 in comparison to the SBR/untreated and SBR/L-NAME groups (P < 0.001). The rats treated with L-Arg had significantly greater villus height and crypt-cell mitoses compared to the other groups (P < 0.0001, P < 0.001). These observations suggest that L-Arg treatment increases villus height and crypt-cell mitoses after massive SBR and may play a considerable role in the mucosal adaptive response in SBS in rats.

Biodegradation of pharmaceuticals in hospital wastewater by staged Moving Bed Biofilm Reactors (MBBR).

PubMed

Casas, Mònica Escolà; Chhetri, Ravi Kumar; Ooi, Gordon; Hansen, Kamilla M S; Litty, Klaus; Christensson, Magnus; Kragelund, Caroline; Andersen, Henrik R; Bester, Kai

2015-10-15

Hospital wastewater represents a significant input of pharmaceuticals into municipal wastewater. As Moving Bed Biofilm Reactors (MBBRs) appear to remove organic micro-pollutants, hospital wastewater was treated with a pilot plant consisting of three MBBRs in series. The removal of pharmaceuticals was studied in two experiments: 1) A batch experiment where pharmaceuticals were spiked to each reactor and 2) a continuous flow experiment at native concentrations. DOC removal, nitrification as well as removal of pharmaceuticals (including X-ray contrast media, β-blockers, analgesics and antibiotics) occurred mainly in the first reactor. In the batch experiment most of the compounds followed a single first-order kinetics degradation function, giving degradation rate constants ranged from 5.77 × 10(-3) to 4.07 h(-1), from -5.53 × 10(-3) to 9.24 × 10(-1) h(-1) and from 1.83 × 10(-3) to 2.42 × 10(-1) h(-1) for first, second and third reactor respectively. Generally, the highest removal rate constants were found in the first reactor while the lowest were found in the third one. This order was inverted for most compounds, when the removal rate constants were normalized to biomass, indicating that the last tank had the most effective biofilms. In the batch experiment, 21 out of 26 compounds were assessed to be degraded with more than 20% within the MBBR train. In the continuous flow experiment the measured removal rates were lower than those estimated from the batch experiments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of chlortetracycline amended feed on anaerobic sequencing batch reactor performance of swine manure digestion.

PubMed

Dreher, Teal M; Mott, Henry V; Lupo, Christopher D; Oswald, Aaron S; Clay, Sharon A; Stone, James J

2012-12-01

The effects of antimicrobial chlortetracycline (CTC) on the anaerobic digestion (AD) of swine manure slurry using anaerobic sequencing batch reactors (ASBRs) was investigated. Reactors were loaded with manure collected from pigs receiving CTC and no-antimicrobial amended diets at 2.5 g/L/d. The slurry was intermittently fed to four 9.5L lab-scale anaerobic sequencing batch reactors, two with no-antimicrobial manure, and two with CTC-amended manure, and four 28 day ASBR cycles were completed. The CTC concentration within the manure was 2 8 mg/L immediately after collection and 1.02 mg/L after dilution and 250 days of storage. CTC did not inhibit ASBR biogas production extent, however the volumetric composition of methane was significantly less (approximately 13% and 15% for cycles 1 and 2, respectively) than the no-antimicrobial through 56 d. CTC decreased soluble chemical oxygen demand and acetic acid utilization through 56 d, after which acclimation to CTC was apparent for the duration of the experiment. Copyright © 2012 Elsevier Ltd. All rights reserved.

A study on the use of the BioBall® as a biofilm carrier in a sequencing batch reactor.

PubMed

Masłoń, Adam; Tomaszek, Janusz A

2015-11-01

Described in this study are experiments conducted to evaluate the removal of organics and nutrients from synthetic wastewater by a moving bed sequencing batch biofilm reactor using BioBall® carriers as biofilm media. The work involving a 15L-laboratory scale MBSBBR (moving bed sequencing batch biofilm reactor) model showed that the wastewater treatment system was based on biochemical processes taking place with activated sludge and biofilm microorganisms developing on the surface of the BioBall® carriers. Classical nitrification and denitrification and the typical enhanced biological phosphorus removal process were achieved in the reactor analyzed, which operated with a volumetric organic loading of 0.84-0.978gCODL(-1)d(-1). The average removal efficiencies for COD, total nitrogen and total phosphorus were found to be 97.7±0.5%, 87.8±2.6% and 94.3±1.3%, respectively. Nitrification efficiency reached levels in the range 96.5-99.7%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase

DOE PAGES

Wang, Jun; Liu, Xi; Wang, Xu -Dong; ...

2016-08-18

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7 °C) and decrease ofmore » crystallizing point (3 °C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from 212.3 to 14.6 per batch with the microreactor. Altogether, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts.« less

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase

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

Wang, Jun; Liu, Xi; Wang, Xu -Dong

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7 °C) and decrease ofmore » crystallizing point (3 °C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from 212.3 to 14.6 per batch with the microreactor. Altogether, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts.« less

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase.

PubMed

Wang, Jun; Liu, Xi; Wang, Xu-Dong; Dong, Tao; Zhao, Xing-Yu; Zhu, Dan; Mei, Yi-Yuan; Wu, Guo-Hua

2016-11-01

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7°C) and decrease of crystallizing point (3°C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from $212.3 to $14.6 per batch with the microreactor. Overall, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of dissolved CO2 on Shallow Freshwater Microbial Communities simulating a CO2 Leakage Scenario

NASA Astrophysics Data System (ADS)

Gulliver, D. M.; Lowry, G. V.; Gregory, K.

2013-12-01

Geological carbon sequestration is likely to be part of a comprehensive strategy to minimize the atmospheric release of greenhouse gasses, establishing a concern of sequestered CO2 leakage into overlying potable aquifers. Leaking CO2 may affect existing biogeochemical processes and therefore water quality. There is a critical need to understand the evolution of CO2 exposed microbial communities that influence the biogeochemistry in these freshwater aquifers. The evolution of microbial ecology for different CO2 exposure concentrations was investigated using fluid-slurry samples obtained from a shallow freshwater aquifer (55 m depth, 0.5 MPa, 22 °C, Escatawpa, MS). The microbial community of well samples upstream and downstream of CO2 injection was characterized. In addition, batch vessel experiments were conducted with the upstream aquifer samples exposed to varying pCO2 from 0% to 100% under reservoir temperature and pressure for up to 56 days. The microbial community of the in situ experiment and the batch reactor experiment were analyzed with 16S rRNA clone libraries and qPCR. In both the in situ experiment and the batch reactor experiment, DNA concentration did not correlate with CO2 exposure. Both the in situ experiment and the batch reactors displayed a changing microbial community with increased CO2 exposure. The well water isolate, Curvibacter, appeared to be the most tolerant genus to high CO2 concentrations in the in situ experiments and to mid-CO2 concentrations in the batch reactors. In batch reactors with pCO2 concentrations higher than experienced in situ (pCO2 = 0.5 MPa), Pseudomonas appeared to be the most tolerant genus. Findings provide insight into a dynamic biogeochemical system that will alter with CO2 exposure. Adapted microbial populations will eventually give rise to the community that will impact the metal mobility and water quality. Knowledge of the surviving microbial populations will enable improved models for predicting the fate of CO2 following leakage and lead to better strategies for ensuring the quality of potable aquifer water.

Effect of organo clay on curing, mechanical and dielectric properties of NR/SBR blends

NASA Astrophysics Data System (ADS)

Ravikumar, K.; Joseph, Reji; Ravichandran, K.

2018-04-01

Natural rubber (NR) and styrene butadiene rubber (SBR) based elastomeric blends reinforced with organically modified Sodium bentonite clay were prepared by two roll mills. Vulcanization parameters such as minimum and maximum torque values scorch and cure times are measured by Oscillating Disc Rheometer. Mechanical properties such as Tensile strength, modulus at 100%, 200% and 300% elongation and elongation at break and Hardness were measured by Universal testing machine and Durometer Shore A hardness meter respectively. Dielectric properties such as dielectric constant (ε’), dissipation factor (tanδ) and volume resistivity (ρv) were measured at room temperature. The curing studies show that torque values are increasing in NR/SBR blends by increase NR content. The scorch and optimum cure time in NR/SBR blends reinforced organo modified clay was found through increase in the SBR content. This may be due to better processing safety of the NR/SBR blends reinforced with organo modified clay. Mechanical properties show that addition of SBR in blends, tensile strength, elongation modulus increases, but 100% modulus slightly increases and no change was observed in Hardness. Dielectric studies show that dielectric constant of NR and SBR rubbers are almost same, it may due to their non-polar nature. But addition of SBR in NR/SBR blend, dielectric constant gradually increases and maximum value observed at 50/50 ratio. But no considerable change was observed in dissipation factor. Frequency dependant resistivity shows that volume resistivity was not changed with respect to frequency up to 3.5 kHz and beyond that the frequency dependence resistivity was found.

[Development of a Striatal and Skull Phantom for Quantitative 123I-FP-CIT SPECT].

PubMed

Ishiguro, Masanobu; Uno, Masaki; Miyazaki, Takuma; Kataoka, Yumi; Toyama, Hiroshi; Ichihara, Takashi

123 Iodine-labelled N-(3-fluoropropyl) -2β-carbomethoxy-3β-(4-iodophenyl) nortropane ( 123 I-FP-CIT) single photon emission computerized tomography (SPECT) images are used for differential diagnosis such as Parkinson's disease (PD). Specific binding ratio (SBR) is affected by scattering and attenuation in SPECT imaging, because gender and age lead to changes in skull density. It is necessary to clarify and correct the influence of the phantom simulating the the skull. The purpose of this study was to develop phantoms that can evaluate scattering and attenuation correction. Skull phantoms were prepared based on the measuring the results of the average computed tomography (CT) value, average skull thickness of 12 males and 16 females. 123 I-FP-CIT SPECT imaging of striatal phantom was performed with these skull phantoms, which reproduced normal and PD. SPECT images, were reconstructed with scattering and attenuation correction. SBR with partial volume effect corrected (SBR act ) and conventional SBR (SBR Bolt ) were measured and compared. The striatum and the skull phantoms along with 123 I-FP-CIT were able to reproduce the normal accumulation and disease state of PD and further those reproduced the influence of skull density on SPECT imaging. The error rate with the true SBR, SBR act was much smaller than SBR Bolt . The effect on SBR could be corrected by scattering and attenuation correction even if the skull density changes with 123 I-FP-CIT on SPECT imaging. The combination of triple energy window method and CT-attenuation correction method would be the best correction method for SBR act .

Six Weeks Habituation of Simulated Barefoot Running Induces Neuromuscular Adaptations and Changes in Foot Strike Patterns in Female Runners

PubMed Central

Khowailed, Iman Akef; Petrofsky, Jerrold; Lohman, Everett; Daher, Noha

2015-01-01

Background The aim of this study was to examine the effects of a 6-week training program of simulated barefoot running (SBR) on running kinetics in habitually shod (wearing shoes) female recreational runners. Material/Methods Twelve female runners age 25.7±3.4 years gradually increased running distance in Vibram FiveFingers minimal shoes over a 6-week period. The kinetic analysis of treadmill running at 10 Km/h was performed pre- and post-intervention in shod running, non-habituated SBR, and habituated SBR conditions. Spatiotemporal parameters, ground reaction force components, and electromyography (EMG) were measured in all conditions. Results Post-intervention data indicated a significant decrease across time in the habituation SBR for EMG activity of the tibialis anterior (TA) in the pre-activation and absorptive phase of running (P<0.001). A significant increase was denoted in the pre-activation amplitude of the gastrocnemius (GAS) between the shod running, unhabituated SBR, and habituated SBR. Six weeks of SBR was associated with a significant decrease in the loading rates and impact forces. Additionally, SBR significantly decrease the stride length, step duration, and flight time, and stride frequency was significantly higher compared to shod running. Conclusions The findings of this study indicate that changes in motor patterns in previously habitually shod runners are possible and can be accomplished within 6 weeks. Non-habituation SBR did not show a significant neuromuscular adaptation in the EMG activity of TA and GAS as manifested after 6 weeks of habituated SBR. PMID:26166443

The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams

PubMed Central

Shao, Liang; Ji, Zhan-You; Ma, Jian-Zhong; Xue, Chao-Hua; Ma, Zhong-Lei; Zhang, Jing

2016-01-01

Sulfur (S) cross-linking styrene butadiene rubber (SBR) foams show high shrinkage due to the cure reversion, leading to reduced yield and increased processing cost. In this paper, double cross-linking system by S and dicumyl peroxide (DCP) was used to decrease the shrinkage of SBR foams. Most importantly, the synergy of double cross-linking agents was reported for the first time to our knowledge. The cell size and its distribution of SBR foams were investigated by FESEM images, which show the effect of DCP content on the cell structure of the SBR foams. The relationships between shrinkage and crystalline of SBR foams were analyzed by the synergy of double cross-linking agents, which were demonstrated by FTIR, Raman spectra, XRD, DSC and TGA. When the DCP content was 0.6 phr, the SBR foams exhibit excellent physical and mechanical properties such as low density (0.223 g/cm3), reduced shrinkage (2.25%) and compression set (10.96%), as well as elevated elongation at break (1.78 × 103%) and tear strength (54.63 N/mm). The results show that these properties are related to the double cross-linking system of SBR foams. Moreover, the double cross-linking SBR foams present high electromagnetic interference (EMI) shielding properties compared with the S cross-linking SBR foams. PMID:27841307

The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams

NASA Astrophysics Data System (ADS)

Shao, Liang; Ji, Zhan-You; Ma, Jian-Zhong; Xue, Chao-Hua; Ma, Zhong-Lei; Zhang, Jing

2016-11-01

Sulfur (S) cross-linking styrene butadiene rubber (SBR) foams show high shrinkage due to the cure reversion, leading to reduced yield and increased processing cost. In this paper, double cross-linking system by S and dicumyl peroxide (DCP) was used to decrease the shrinkage of SBR foams. Most importantly, the synergy of double cross-linking agents was reported for the first time to our knowledge. The cell size and its distribution of SBR foams were investigated by FESEM images, which show the effect of DCP content on the cell structure of the SBR foams. The relationships between shrinkage and crystalline of SBR foams were analyzed by the synergy of double cross-linking agents, which were demonstrated by FTIR, Raman spectra, XRD, DSC and TGA. When the DCP content was 0.6 phr, the SBR foams exhibit excellent physical and mechanical properties such as low density (0.223 g/cm3), reduced shrinkage (2.25%) and compression set (10.96%), as well as elevated elongation at break (1.78 × 103%) and tear strength (54.63 N/mm). The results show that these properties are related to the double cross-linking system of SBR foams. Moreover, the double cross-linking SBR foams present high electromagnetic interference (EMI) shielding properties compared with the S cross-linking SBR foams.

Enzymatic Continuous Flow Synthesis of Thiol-Terminated Poly(δ-Valerolactone) and Block Copolymers.

PubMed

Zhu, Ning; Huang, Weijun; Hu, Xin; Liu, Yihuan; Fang, Zheng; Guo, Kai

2018-04-01

Thiol-terminated poly(δ-valerolactone) is directly synthesized via enzymatic 6-mercapto-1-hexanol initiated ring-opening polymerization in both batch and microreactor. By using Candida antartica Lipase B immobilized tubular reactor, narrowly dispersed poly(δ-valerolactone) with higher thiol fidelity is more efficiently prepared in contrast to the batch reactor. Moreover, the integrated enzyme packed tubular reactor system is established to perform the chain extension experiments. Thiol-terminated poly(δ-valerolactone)-block-poly(ε-caprolactone) and poly(ε-caprolactone)-block-poly(δ-valerolactone) are easily prepared by modulating the monomer introduction sequence. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Performance Graphene Oxide Based Rubber Composites

PubMed Central

Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

2013-01-01

In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications. PMID:23974435

High performance graphene oxide based rubber composites.

PubMed

Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W; Zhang, Liqun; Liang, Yongri; Liu, Li

2013-01-01

In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications.

High solid fed-batch butanol fermentation with simultaneous product recovery: part II - process integration.

USDA-ARS?s Scientific Manuscript database

In these studies liquid hot water (LHW) pretreated and enzymatically hydrolyzed Sweet Sorghum Bagasse (SSB) hydrolyzates were fermented in a fed-batch reactor. As reported in the preceding paper, the culture was not able to ferment the hydrolyzate I in a batch process due to presence of high level o...

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.

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.

Gypsum crystal size distribution in four continuous flow stirred slurry boric acid reactors in series compared with the batch

NASA Astrophysics Data System (ADS)

Çakal, G. Ö.; Eroğlu, İ.; Özkar, S.

2006-04-01

Colemanite, one of the important boron minerals, is dissolved in aqueous sulfuric acid to produce boric acid. In this reaction, gypsum is obtained as a by-product. Gypsum crystals are in the shape of thin needles. These crystals should be grown to an easily filterable size in order to increase the production yield and purity of boric acid. In this paper, the particle size distributions and the volume-weighted mean diameters of the gypsum crystals obtained in batch and continuous flow systems were compared. Experiments in both batch and continuous reactors were performed at a temperature of 85 °C, a stirring rate of 400 rpm, and the inlet CaO to SO42- molar ratio of 1.0 using colemanite mineral in particle size smaller than 150 μm. The average diameter of the gypsum crystals obtained at 3.5 h from the batch reactor was found to be 37-41 μm. This value for the continuous system at steady state was observed to change between 44-163 μm. The particle size of the gypsum crystals was found to increase with the residence time of the solid in the continuous system.

Characteristics of aerobic granules grown on glucose a sequential batch shaking reactor.

PubMed

Cai, Chun-guang; Zhu, Nan-wen; Liu, Jun-shen; Wang, Zhen-peng; Cai, Wei-min

2004-01-01

Aerobic heterotrophic granular sludge was cultivated in a sequencing batch shaking reactor (SBSR) in which a synthetic wastewater containing glucose as carbon source was fed. The characteristics of the aerobic granules were investigated. Compared with the conventional activated sludge flocs, the aerobic granules exhibit excellent physical characteristics in terms of settleability, size, shape, biomass density, and physical strength. Scanning electron micrographs revealed that in mature granules little filamentous bacteria could be found, rod-shaped and coccoid bacteria were the dominant microorganisms.

Biodegradation of Jet Fuel-4 (JP-4) in Sequencing Batch Reactors

DTIC Science & Technology

1992-06-01

nalw~eo %CUMENTATION PAGE__ _ _ _ _ _ _ _ _O 74S Ab -A258 020 L AW POi~W6 DATI .~ TYP AIMqm ,-& 0 U. glbs A~ I ma"&LFUN Mu BIODEGRADATION OF JET FUEL...Specific Objectives of This Proposal Are: 1. To assess the ability of C. resinae , P. chrysosporium and selected bacterial consortia to degrade individual...chemical components of JP-4. 2. To develop a sequencing batch reactor that utilizes C. resinae to degrade chemical components of JP-4 in contaminated

Biotic and abiotic dynamics of a high solid-state anaerobic digestion box-type container system.

PubMed

Walter, Andreas; Probst, Maraike; Hinterberger, Stephan; Müller, Horst; Insam, Heribert

2016-03-01

A solid-state anaerobic digestion box-type container system for biomethane production was observed in 12 three-week batch fermentations. Reactor performance was monitored using physico-chemical analysis and the methanogenic community was identified using ANAEROCHIP-microarrays and quantitative PCR. A resilient community was found in all batches, despite variations in inoculum to substrate ratio, feedstock quality, and fluctuating reactor conditions. The consortia were dominated by mixotrophic Methanosarcina that were accompanied by hydrogenotrophic Methanobacterium, Methanoculleus, and Methanocorpusculum. The relationship between biotic and abiotic variables was investigated using bivariate correlation analysis and univariate analysis of variance. High amounts of biogas were produced in batches with high copy numbers of Methanosarcina. High copy numbers of Methanocorpusculum and extensive percolation, however, were found to negatively correlate with biogas production. Supporting these findings, a negative correlation was detected between Methanocorpusculum and Methanosarcina. Based on these results, this study suggests Methanosarcina as an indicator for well-functioning reactor performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-performance recombinant protein production with Escherichia coli in continuously operated cascades of stirred-tank reactors.

PubMed

Schmideder, Andreas; Weuster-Botz, Dirk

2017-07-01

The microbial expression of intracellular, recombinant proteins in continuous bioprocesses suffers from low product concentrations. Hence, a process for the intracellular production of photoactivatable mCherry with Escherichia coli in a continuously operated cascade of two stirred-tank reactors was established to separate biomass formation (first reactor) and protein expression (second reactor) spatially. Cascades of miniaturized stirred-tank reactors were implemented, which enable the 24-fold parallel characterization of cascade processes and the direct scale-up of results to the liter scale. With PAmCherry concentrations of 1.15 g L -1 cascades of stirred-tank reactors improved the process performance significantly compared to production processes in chemostats. In addition, an optimized fed-batch process was outperformed regarding space-time yield (149 mg L -1  h -1 ). This study implicates continuous cascade processes to be a promising alternative to fed-batch processes for microbial protein production and demonstrates that miniaturized stirred-tank reactors can reduce the timeline and costs for cascade process characterization.

Continuous production of butanol from starch-based packing peanuts.

PubMed

Ezeji, Thaddeus C; Groberg, Marisa; Qureshi, Nasib; Blaschek, Hans P

2003-01-01

Acetone, butanol, ethanol (ABE, or solvents) were produced from starch-based packing peanuts in batch and continuous reactors. In a batch reactor, 18.9 g/L of total ABE was produced from 80 g/L packing peanuts in 110 h of fermentation. The initial and final starch concentrations were 69.6 and 11.1 g/L, respectively. In this fermentation, ABE yield and productivity of 0.32 and 0.17 g/(L h) were obtained, respectively. Compared to the batch fermentation, continuous fermentation of 40 g/L of starchbased packing peanuts in P2 medium resulted in a maximum solvent production of 8.4 g/L at a dilution rate of 0.033 h-1. This resulted in a productivity of 0.27 g/(L h). However, the reactor was not stable and fermentation deteriorated with time. Continuous fermentation of 35 g/L of starch solution resulted in a similar performance. These studies were performed in a vertical column reactor using Clostridium beijerinckii BA101 and P2 medium. It is anticipated that prolonged exposure of culture to acrylamide, which is formed during boiling/autoclaving of starch, affects the fermentation negatively.

Application of real-time PCR to determination of combined effect of antibiotics on Bacteria, Methanogenic Archaea, Archaea in anaerobic sequencing batch reactors.

PubMed

Aydin, Sevcan; Ince, Bahar; Ince, Orhan

2015-06-01

This study evaluated the long-term effects of erythromycin-tetracycline-sulfamethoxazole (ETS) and sulfamethoxazole-tetracycline (ST) antibiotic combinations on the microbial community and examined the ways in which these antimicrobials impact the performance of anaerobic reactors. Quantitative real-time PCR was used to determine the effect that different antibiotic combinations had on the total and active Bacteria, Archae and Methanogenic Archae. Three primer sets that targeted metabolic genes encoding formylterahydrofolate synthetase, methyl-coenzyme M reductase and acetyl-coA synthetase were also used to determine the inhibition level on the mRNA expression of the homoacetogens, methanogens and specifically acetoclastic methanogens, respectively. These microorganisms play a vital role in the anaerobic degradation of organic waste and targeting these gene expressions offers operators or someone at a treatment plant the potential to control and the improve the anaerobic system. The results of the investigation revealed that acetogens have a competitive advantage over Archaea in the presence of ETS and ST combinations. Although the efficiency with which methane production takes place and the quantification of microbial populations in both the ETS and ST reactors decreased as antibiotic concentrations increased, the ETS batch reactor performed better than the ST batch reactor. According to the expression of genes results, the syntrophic interaction of acetogens and methanogens is critical to the performance of the ETS and ST reactors. Failure to maintain the stability of these microorganisms resulted in a decrease in the performance and stability of the anaerobic reactors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Conversion of H2 and CO2 to CH4 and acetate in fed-batch biogas reactors by mixed biogas community: a novel route for the power-to-gas concept.

PubMed

Szuhaj, Márk; Ács, Norbert; Tengölics, Roland; Bodor, Attila; Rákhely, Gábor; Kovács, Kornél L; Bagi, Zoltán

2016-01-01

Applications of the power-to-gas principle for the handling of surplus renewable electricity have been proposed. The feasibility of using hydrogenotrophic methanogens as CH4 generating catalysts has been demonstrated. Laboratory and scale-up experiments have corroborated the benefits of the CO2 mitigation via biotechnological conversion of H2 and CO2 to CH4. A major bottleneck in the process is the gas-liquid mass transfer of H2. Fed-batch reactor configuration was tested at mesophilic temperature in laboratory experiments in order to improve the contact time and H2 mass transfer between the gas and liquid phases. Effluent from an industrial biogas facility served as biocatalyst. The bicarbonate content of the effluent was depleted after some time, but the addition of stoichiometric CO2 sustained H2 conversion for an extended period of time and prevented a pH shift. The microbial community generated biogas from the added α-cellulose substrate with concomitant H2 conversion, but the organic substrate did not facilitate H2 consumption. Fed-batch operational mode allowed a fourfold increase in volumetric H2 load and a 6.5-fold augmentation of the CH4 formation rate relative to the CSTR reactor configuration. Acetate was the major by-product of the reaction. Fed-batch reactors significantly improve the efficiency of the biological power-to-gas process. Besides their storage function, biogas fermentation effluent reservoirs can serve as large-scale bio CH4 reactors. On the basis of this recognition, a novel concept is proposed, which merges biogas technology with other means of renewable electricity production for improved efficiency and sustainability.

Effect of bioaugmentation by cellulolytic bacteria enriched from sheep rumen on methane production from wheat straw.

PubMed

Ozbayram, E Gozde; Kleinsteuber, Sabine; Nikolausz, Marcell; Ince, Bahar; Ince, Orhan

2017-08-01

The aim of this study was to determine the potential of bioaugmentation with cellulolytic rumen microbiota to enhance the anaerobic digestion of lignocellulosic feedstock. An anaerobic cellulolytic culture was enriched from sheep rumen fluid using wheat straw as substrate under mesophilic conditions. To investigate the effects of bioaugmentation on methane production from straw, the enrichment culture was added to batch reactors in proportions of 2% (Set-1) and 4% (Set-2) of the microbial cell number of the standard inoculum slurry. The methane production in the bioaugmented reactors was higher than in the control reactors. After 30 days of batch incubation, the average methane yield was 154 mL N CH 4 g VS -1 in the control reactors. Addition of 2% enrichment culture did not enhance methane production, whereas in Set-2 the methane yield was increased by 27%. The bacterial communities were examined by 454 amplicon sequencing of 16S rRNA genes, while terminal restriction fragment length polymorphism (T-RFLP) fingerprinting of mcrA genes was applied to analyze the methanogenic communities. The results highlighted that relative abundances of Ruminococcaceae and Lachnospiraceae increased during the enrichment. However, Cloacamonaceae, which were abundant in the standard inoculum, dominated the bacterial communities of all batch reactors. T-RFLP profiles revealed that Methanobacteriales were predominant in the rumen fluid, whereas the enrichment culture was dominated by Methanosarcinales. In the batch rectors, the most abundant methanogens were affiliated to Methanobacteriales and Methanomicrobiales. Our results suggest that bioaugmentation with sheep rumen enrichment cultures can enhance the performance of digesters treating lignocellulosic feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of expert opinions on the selection of wastewater treatment alternatives: a group decision-making approach.

PubMed

Kalbar, Pradip P; Karmakar, Subhankar; Asolekar, Shyam R

2013-10-15

The application of multiple-attribute decision-making (MADM) to real life decision problems suggests that avoiding the loss of information through scenario-based approaches and including expert opinions in the decision-making process are two major challenges that require more research efforts. Recently, a wastewater treatment technology selection effort has been made with a 'scenario-based' method of MADM. This paper focuses on a novel approach to incorporate expert opinions into the scenario-based decision-making process, as expert opinions play a major role in the selection of treatment technologies. The sets of criteria and the indicators that are used consist of both qualitative and quantitative criteria. The group decision-making (GDM) approach that is implemented for aggregating expert opinions is based on an analytical hierarchy process (AHP), which is the most widely used MADM method. The pairwise comparison matrices (PCMs) for qualitative criteria are formed based on expert opinions, whereas, a novel approach is proposed for generating PCMs for quantitative criteria. It has been determined that the experts largely prefer natural treatment systems because they are more sustainable in any scenario. However, PCMs based on expert opinions suggest that advanced technologies such as the sequencing batch reactor (SBR) can also be appropriate for a given decision scenario. The proposed GDM approach is a rationalized process that will be more appropriate in realistic scenarios where multiple stakeholders with local and regional societal priorities are involved in the selection of treatment technology. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous improvement of waste gas purification and nitrogen removal using a novel aerated vertical flow constructed wetland.

PubMed

Zhang, Xinwen; Hu, Zhen; Ngo, Huu Hao; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Xie, Huijun

2018-03-01

Insufficient oxygen supply is identified as one of the major factors limiting organic pollutant and nitrogen (N) removal in constructed wetlands (CWs). This study designed a novel aerated vertical flow constructed wetland (VFCW) using waste gas from biological wastewater treatment systems to improve pollutant removal in CWs, its potential in purifying waste gas was also identified. Compared with unaerated VFCW, the introduction of waste gas significantly improved NH 4 + -N and TN removal efficiencies by 128.48 ± 3.13% and 59.09 ± 2.26%, respectively. Furthermore, the waste gas ingredients, including H 2 S, NH 3 , greenhouse gas (N 2 O) and microbial aerosols, were remarkably reduced after passing through the VFCW. The removal efficiencies of H 2 S, NH 3 and N 2 O were 77.78 ± 3.46%, 52.17 ± 2.53%, and 87.40 ± 3.89%, respectively. In addition, the bacterial and fungal aerosols in waste gas were effectively removed with removal efficiencies of 42.72 ± 3.21% and 47.89 ± 2.82%, respectively. Microbial analysis results revealed that the high microbial community abundance in the VFCW, caused by the introduction of waste gas from the sequencing batch reactor (SBR), led to its optimized nitrogen transformation processes. These results suggested that the VFCW intermittently aerated with waste gas may have potential application for purifying wastewater treatment plant effluent and waste gas, simultaneously. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mathematical modeling of nitrous oxide (N2O) emissions from full-scale wastewater treatment plants.

PubMed

Ni, Bing-Jie; Ye, Liu; Law, Yingyu; Byers, Craig; Yuan, Zhiguo

2013-07-16

Mathematical modeling of N2O emissions is of great importance toward understanding the whole environmental impact of wastewater treatment systems. However, information on modeling of N2O emissions from full-scale wastewater treatment plants (WWTP) is still sparse. In this work, a mathematical model based on currently known or hypothesized metabolic pathways for N2O productions by heterotrophic denitrifiers and ammonia-oxidizing bacteria (AOB) is developed and calibrated to describe the N2O emissions from full-scale WWTPs. The model described well the dynamic ammonium, nitrite, nitrate, dissolved oxygen (DO) and N2O data collected from both an open oxidation ditch (OD) system with surface aerators and a sequencing batch reactor (SBR) system with bubbling aeration. The obtained kinetic parameters for N2O production are found to be reasonable as the 95% confidence regions of the estimates are all small with mean values approximately at the center. The model is further validated with independent data sets collected from the same two WWTPs. This is the first time that mathematical modeling of N2O emissions is conducted successfully for full-scale WWTPs. While clearly showing that the NH2OH related pathways could well explain N2O production and emission in the two full-scale plants studied, the modeling results do not prove the dominance of the NH2OH pathways in these plants, nor rule out the possibility of AOB denitrification being a potentially dominating pathway in other WWTPs that are designed or operated differently.

Treatment of HMX-production wastewater in an aerobic granular reactor.

PubMed

Zhang, Jin-Hua; Wang, Min-Hui; Zhu, Xiao-Meng

2013-04-01

Aerobic granules were applied to the treatment of HMX-production wastewater using a gradual domestication method in a SBR. During the process, the granules showed a good settling ability, a high biomass retention rate, and high biological activity. After 40 days of stable operation, aerobic granular sludge performed very effectively in the removal of carbon and nitrogen compounds from HMX-production wastewater. Organic matter removal rates up to 97.57% and nitrogen removal efficiencies up to 80% were achieved during the process. Researchers conclude that using aerobic granules to treat explosive wastewater has good prospects for success.

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.

PHYTO-REMOVAL OF TRINITROTOLUENE FROM WATER WITH BATCH KINETIC STUDIES

EPA Science Inventory

A series of batch reactor studies were conducted to obtain kinetic data for optimizing phyto-treatment of water contaminated with trinitrotoluene (TNT). A plant screening study indicated that stonewort and parrotfeather were the most effective among the plants tested; parrotfeath...

Economic Evaluation of Two Biological Processes for Treatment of Ball Powder Production Wastewater

DTIC Science & Technology

1989-02-01

Collection and Equalization 2-1 2.2 System 200 - pH and Nutrient Control 2-1 2.3 System 300 - Extended Aeration and Aerobic Digestion 2-4 2.4 System...400 - Sequencing Batch Reactor and Aerobic Digestion 2-4 2.5 System 500 - Sludge Dewatering and Control Building 2-7 1 3.0 COST ESTIMATION AND...Extended Aeration and Aerobic Digestion 2-5 2.4 400 - Sequencing Batch Reactors and Aerobic Digestion 2-6 2.5 500 - Sludge Dewatering 2-8 Artur D Little

Silica-Supported Catalyst for Enantioselective Arylation of Aldehydes under Batch and Continuous-Flow Conditions.

PubMed

Watanabe, Satoshi; Nakaya, Naoyuki; Akai, Junichiro; Kanaori, Kenji; Harada, Toshiro

2018-05-04

A silica-supported 3-aryl H 8 -BINOL-derived titanium catalyst exhibited high performance in the enantioselective arylation of aromatic aldehydes using Grignard and organolithium reagents not only under batch conditions but also under continuous-flow conditions. Even with a simple pipet reactor packed with the heterogeneous catalyst, the enantioselective production of chiral diarylmethanols could be achieved through a continuous introduction of aldehydes and mixed titanium reagents generated from the organometallic precursors. The pipet reactor could be used repeatedly in different reactions without appreciable deterioration of the activity.

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

PubMed

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

2005-09-01

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

Repeated-batch operation of immobilized β-galactosidase inclusion bodies-containing Escherichia coli cell reactor for lactose hydrolysis.

PubMed

Yeon, Ji-Hyeon; Jung, Kyung-Hwan

2011-09-01

In this study, we investigated the performance of an immobilized β-galactosidase inclusion bodies-containing Escherichia coli cell reactor, where the cells were immobilized in alginate beads, which were then used in repeated-batch operations for the hydrolysis of o-nitrophenyl-β-D-galactoside or lactose over the long-term. In particular, in the Tris buffer system, disintegration of the alginate beads was not observed during the operation, which was observed for the phosphate buffer system. The o-nitrophenyl-β-D-galactoside hydrolysis was operated successfully up to about 80 h, and the runs were successfully repeated at least eight times. In addition, hydrolysis of lactose was successfully carried out up to 240 h. Using Western blotting analyses, it was verified that the beta-galactosidase inclusion bodies were sustained in the alginate beads during the repeated-batch operations. Consequently, we experimentally verified that β-galactosidase inclusion bodies-containing Escherichia coli cells could be used in a repeated-batch reactor as a biocatalyst for the hydrolysis of o-nitrophenyl-β-D-galactoside or lactose. It is probable that this approach can be applied to enzymatic synthesis reactions for other biotechnology applications, particularly reactions that require long-term and stable operation.

Performance of the auxotrophic Saccharomyces cerevisiae BY4741 as host for the production of IL-1β in aerated fed-batch reactor: role of ACA supplementation, strain viability, and maintenance energy

PubMed Central

2009-01-01

Background Saccharomyces cerevisiae BY4741 is an auxotrophic commonly used strain. In this work it has been used as host for the expression and secretion of human interleukin-1β (IL1β), using the cell wall protein Pir4 as fusion partner. To achieve high cell density and, consequently, high product yield, BY4741 [PIR4-IL1β] was cultured in an aerated fed-batch reactor, using a defined mineral medium supplemented with casamino acids as ACA (auxotrophy-complementing amino acid) source. Also the S. cerevisiae mutant BY4741 Δyca1 [PIR4-IL1β], carrying the deletion of the YCA1 gene coding for a caspase-like protein involved in the apoptotic response, was cultured in aerated fed-batch reactor and compared to the parental strain, to test the effect of this mutation on strain robustness. Viability of the producer strains was examined during the runs and a mathematical model, which took into consideration the viable biomass present in the reactor and the glucose consumption for both growth and maintenance, was developed to describe and explain the time-course evolution of the process for both, the BY4741 parental and the BY4741 Δyca1 mutant strain. Results Our results show that the concentrations of ACA in the feeding solution, corresponding to those routinely used in the literature, are limiting for the growth of S. cerevisiae BY4741 [PIR4-IL1β] in fed-batch reactor. Even in the presence of a proper ACA supplementation, S. cerevisiae BY4741 [PIR4-IL1β] did not achieve a high cell density. The Δyca1 deletion did not have a beneficial effect on the overall performance of the strain, but it had a clear effect on its viability, which was not impaired during fed-batch operations, as shown by the kd value (0.0045 h-1), negligible if compared to that of the parental strain (0.028 h-1). However, independently of their robustness, both the parental and the Δyca1 mutant ceased to grow early during fed-batch runs, both strains using most of the available carbon source for maintenance, rather than for further proliferation. The mathematical model used evidenced that the energy demand for maintenance was even higher in the case of the Δyca1 mutant, accounting for the growth arrest observed despite the fact that cell viability remained comparatively high. Conclusions The paper points out the relevance of a proper ACA formulation for the outcome of a fed-batch reactor growth carried out with S. cerevisiae BY4741 [PIR4-IL1β] strain and shows the sensitivity of this commonly used auxotrophic strain to aerated fed-batch operations. A Δyca1 disruption was able to reduce the loss of viability, but not to improve the overall performance of the process. A mathematical model has been developed that is able to describe the behaviour of both the parental and mutant producer strain during fed-batch runs, and evidence the role played by the energy demand for maintenance in the outcome of the process. PMID:20042083

Acceptance Test Data for Candidate AGR-5/6/7 TRISO Particle Batches BWXT Coater Batches 93165 93172 Defective IPyC Fraction and Pyrocarbon Anisotropy

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

Helmreich, Grant W.; Hunn, John D.; Skitt, Darren J.

2017-03-01

Coated particle fuel batches J52O-16-93165, 93166, 93168, 93169, 93170, and 93172 were produced by Babcock and Wilcox Technologies (BWXT) for possible selection as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR). Some of these batches may alternately be used as demonstration coated particle fuel for other experiments. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT lot J52R-16-69317 containing a mixture of 15.5%-enriched uranium carbide andmore » uranium oxide (UCO). The TRISO coatings consisted of four consecutive CVD layers: a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μmnominal thickness. The TRISO-coated particle batches were sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batches were designated by appending the letter A to the end of the batch number (e.g., 93165A).« less

High Purity and Yield of Boron Nitride Nanotubes Using Amorphous Boron and a Nozzle-Type Reactor

PubMed Central

Kim, Jaewoo; Seo, Duckbong; Yoo, Jeseung; Jeong, Wanseop; Seo, Young-Soo; Kim, Jaeyong

2014-01-01

Enhancement of the production yield of boron nitride nanotubes (BNNTs) with high purity was achieved using an amorphous boron-based precursor and a nozzle-type reactor. Use of a mixture of amorphous boron and Fe decreases the milling time for the preparation of the precursor for BNNTs synthesis, as well as the Fe impurity contained in the B/Fe interdiffused precursor nanoparticles by using a simple purification process. We also explored a nozzle-type reactor that increased the production yield of BNNTs compared to a conventional flow-through reactor. By using a nozzle-type reactor with amorphous boron-based precursor, the weight of the BNNTs sample after annealing was increased as much as 2.5-times with much less impurities compared to the case for the flow-through reactor with the crystalline boron-based precursor. Under the same experimental conditions, the yield and quantity of BNNTs were estimated as much as ~70% and ~1.15 g/batch for the former, while they are ~54% and 0.78 g/batch for the latter. PMID:28788161

High Purity and Yield of Boron Nitride Nanotubes Using Amorphous Boron and a Nozzle-Type Reactor.

PubMed

Kim, Jaewoo; Seo, Duckbong; Yoo, Jeseung; Jeong, Wanseop; Seo, Young-Soo; Kim, Jaeyong

2014-08-11

Enhancement of the production yield of boron nitride nanotubes (BNNTs) with high purity was achieved using an amorphous boron-based precursor and a nozzle-type reactor. Use of a mixture of amorphous boron and Fe decreases the milling time for the preparation of the precursor for BNNTs synthesis, as well as the Fe impurity contained in the B/Fe interdiffused precursor nanoparticles by using a simple purification process. We also explored a nozzle-type reactor that increased the production yield of BNNTs compared to a conventional flow-through reactor. By using a nozzle-type reactor with amorphous boron-based precursor, the weight of the BNNTs sample after annealing was increased as much as 2.5-times with much less impurities compared to the case for the flow-through reactor with the crystalline boron-based precursor. Under the same experimental conditions, the yield and quantity of BNNTs were estimated as much as ~70% and ~1.15 g/batch for the former, while they are ~54% and 0.78 g/batch for the latter.

Compatibilization of HIPS/ABS blends from WEEE by using Styrene-Butadiene Rubber (SBR).

PubMed

Vazquez, Yamila V; Barbosa, Silvia E

2018-07-01

The aim of this work is to develop compatibilization strategies for High Impact Polystyrene (HIPS)/ Acrylonitrile-Butadiene-Styrene (ABS) blends from WEEE in order to add value to these recycled plastics by improving their mechanical performance. Results from a screening study of HIPS/ABS blends compatibilization by the addition of Styrene-Butadiene Rubber (SBR) are presented. Two different weight proportion of HIPS/ABS physical blends were analyzed, 80/20 and 20/80, with three different concentration of SBR: 2, 10 and 20 wt%. Compatibilization efficiency was analyzed from an accurate thermal and mechanical analysis, by comparing each physical blend and corresponding compatibilized blends with SBR. Results were discussed relating glass transition changes with mechanical performance, both aspects were interpreted in terms of blend morphology. Phase and fillers dispersion and distribution as well as SBR amount and its interaction with each phase were accurate analyzed. Compatibilization of HIPS/ABS blends from WEEE with the addition of SBR is effective in blends with HIPS as main component. With the addition of 2 wt% of SBR, strength and toughness have notably increased respect to the corresponding physical blend, 244% and 186% respectively. From this screening study is possible to infer that SBR is a sustainable and efficient compatibilizer of HIPS rich blends allowing to obtain a final blend that can be used as a replacement material of separated resins from WEEE. Copyright © 2018 Elsevier Ltd. All rights reserved.

ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

EPA Science Inventory

Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

Cocoa residues as viable biomass for renewable energy production through anaerobic digestion.

PubMed

Acosta, Nayaret; De Vrieze, Jo; Sandoval, Verónica; Sinche, Danny; Wierinck, Isabella; Rabaey, Korneel

2018-05-31

The aim of this work was to evaluate the bioenergy potential of cocoa residue via anaerobic digestion. Batch and fed-batch lab-scale reactors were operated under low and high solids conditions. In the batch tests, 59 ± 4% of Chemical Oxygen Demand (COD) was recovered as methane. This corresponded with an average methane yield of 174 (wet) and 193 (dry) L kg -1 volatile solids fed, whereas a series of fed-batch reactors produced 70 ± 24 (wet) and 107 ± 39 (dry) L CH 4  kg -1 volatile solids fed during stable conditions. A case study was developed for canton Balao (Ecuador) based on our experimental data, operational estimates and available cocoa waste in the area. Annually, 8341 MWh could be produced, meeting 88% of the current electricity demand in Balao. This case study proves the potential for cocoa waste as a source of renewable energy in rural areas. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hydrolytic activities of extracellular enzymes in thermophilic and mesophilic anaerobic sequencing-batch reactors treating organic fractions of municipal solid wastes.

PubMed

Kim, Hyun-Woo; Nam, Joo-Youn; Kang, Seok-Tae; Kim, Dong-Hoon; Jung, Kyung-Won; Shin, Hang-Sik

2012-04-01

Extracellular enzymes offer active catalysis for hydrolysis of organic solid wastes in anaerobic digestion. To evidence the quantitative significance of hydrolytic enzyme activities for major waste components, track studies of thermophilic and mesophilic anaerobic sequencing-batch reactors (TASBR and MASBR) were conducted using a co-substrate of real organic wastes. During 1day batch cycle, TASBR showed higher amylase activity for carbohydrate (46%), protease activity for proteins (270%), and lipase activity for lipids (19%) than MASBR. In particular, the track study of protease identified that thermophilic anaerobes degraded protein polymers much more rapidly. Results revealed that differences in enzyme activities eventually affected acidogenic and methanogenic performances. It was demonstrated that the superior nature of enzymatic capability at thermophilic condition led to successive high-rate acidogenesis and 32% higher CH(4) recovery. Consequently, these results evidence that the coupling thermophilic digestion with sequencing-batch operation is a viable option to promote enzymatic hydrolysis of organic particulates. Copyright © 2012 Elsevier Ltd. All rights reserved.

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid.

PubMed

Aw, Alex; Fritz, Marshall; Napoline, Jonathan W; Pollet, Pamela; Liotta, Charles L

2017-11-15

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and cost savings through the "scaling out" strategy as opposed to the traditional "scaling up". Herein, we report the reaction of diphenyldiazomethane with p-nitrobenzoic acid in both batch and flow modes. To effectively transfer the reaction from batch to flow mode, it is essential to first conduct the reaction in batch. As a consequence, the reaction of diphenyldiazomethane was first studied in batch as a function of temperature, reaction time, and concentration to obtain kinetic information and process parameters. The glass flow reactor set-up is described and combines two types of reaction modules with "mixing" and "linear" microstructures. Finally, the reaction of diphenyldiazomethane with p-nitrobenzoic acid was successfully conducted in the flow reactor, with up to 95% conversion of the diphenyldiazomethane in 11 min. This proof of concept reaction aims to provide insight for scientists to consider flow technology's competitiveness, sustainability, and versatility in their research.

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes.

PubMed

García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh; Lema, Juan M; Rodríguez, Jorge; Steyer, Jean-Philippe; Torrijos, Michel

2015-01-01

A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 gVS/Ld. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of different signal-to-background ratios on spatial resolution and F18-FDG-PET quantification using point spread function and time-of-flight reconstruction.

PubMed

Rogasch, Julian Mm; Hofheinz, Frank; Lougovski, Alexandr; Furth, Christian; Ruf, Juri; Großer, Oliver S; Mohnike, Konrad; Hass, Peter; Walke, Mathias; Amthauer, Holger; Steffen, Ingo G

2014-12-01

F18-fluorodeoxyglucose positron-emission tomography (FDG-PET) reconstruction algorithms can have substantial influence on quantitative image data used, e.g., for therapy planning or monitoring in oncology. We analyzed radial activity concentration profiles of differently reconstructed FDG-PET images to determine the influence of varying signal-to-background ratios (SBRs) on the respective spatial resolution, activity concentration distribution, and quantification (standardized uptake value [SUV], metabolic tumor volume [MTV]). Measurements were performed on a Siemens Biograph mCT 64 using a cylindrical phantom containing four spheres (diameter, 30 to 70 mm) filled with F18-FDG applying three SBRs (SBR1, 16:1; SBR2, 6:1; SBR3, 2:1). Images were reconstructed employing six algorithms (filtered backprojection [FBP], FBP + time-of-flight analysis [FBP + TOF], 3D-ordered subset expectation maximization [3D-OSEM], 3D-OSEM + TOF, point spread function [PSF], PSF + TOF). Spatial resolution was determined by fitting the convolution of the object geometry with a Gaussian point spread function to radial activity concentration profiles. MTV delineation was performed using fixed thresholds and semiautomatic background-adapted thresholding (ROVER, ABX, Radeberg, Germany). The pairwise Wilcoxon test revealed significantly higher spatial resolutions for PSF + TOF (up to 4.0 mm) compared to PSF, FBP, FBP + TOF, 3D-OSEM, and 3D-OSEM + TOF at all SBRs (each P < 0.05) with the highest differences for SBR1 decreasing to the lowest for SBR3. Edge elevations in radial activity profiles (Gibbs artifacts) were highest for PSF and PSF + TOF declining with decreasing SBR (PSF + TOF largest sphere; SBR1, 6.3%; SBR3, 2.7%). These artifacts induce substantial SUVmax overestimation compared to the reference SUV for PSF algorithms at SBR1 and SBR2 leading to substantial MTV underestimation in threshold-based segmentation. In contrast, both PSF algorithms provided the lowest deviation of SUVmean from reference SUV at SBR1 and SBR2. At high contrast, the PSF algorithms provided the highest spatial resolution and lowest SUVmean deviation from the reference SUV. In contrast, both algorithms showed the highest deviations in SUVmax and threshold-based MTV definition. At low contrast, all investigated reconstruction algorithms performed approximately equally. The use of PSF algorithms for quantitative PET data, e.g., for target volume definition or in serial PET studies, should be performed with caution - especially if comparing SUV of lesions with high and low contrasts.

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes

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

García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh

2015-01-15

Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowlymore » biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.« less

Reductive Dechlorination of Carbon Tetrachloride by Tetrachloroethene and Trichloroethene Respiring Anaerobic Mixed Cultures

NASA Astrophysics Data System (ADS)

Vickstrom, K. E.; Azizian, M.; Semprini, L.

2015-12-01

Carbon tetrachloride (CT) is a toxic and recalcitrant groundwater contaminant with the potential to form a broad range of transformation products. Of the possible biochemical pathways through which CT can be degraded, reductive dehalogenation to less chlorinated compounds and mineralization to carbon dioxide (CO2) appear to be the most frequently utilized pathways by anaerobic organisms. Results will be presented from batch experiments of CT degradation by the Evanite (EV), Victoria Strain (VS) and Point Mugu (PM) anaerobic dechlorinating cultures. The cultures are grown in chemostats and are capable of transforming tetrachloroethene (PCE) or trichloroethene (TCE) to ethene by halorespiration via reductive dehalogenase enzymes. For the batch CT transformation tests, the cells along with supernatant were harvested from chemostats fed PCE or TCE, but never CT. The batch reactors were initially fed 0.0085 mM CT and an excess of formate (EV and VS) or lactate (PM) as electron donor. Transformation of CT was 100% with about 20% converted to chloroform (CF) and undetected products. Multiple additions of CT showed a slowing of pseudo first-order CT transformation rates across all cultures. Batch reactors were then established and fed 0.085 mM CT with an excess of electron donor in order to better quantify the reductive pathway. CT was transformed to CF and dichloromethane (DCM), with trace amounts of chloromethane (CM) detected. Between 60-90% of the mass added to the system was accounted for, showing that the majority of the carbon tetrachloride present is being reductively dehalogenated. Results from batch reactors that were poisoned using sodium azide, and from reactors not provided electron donor will be presented to distinguish between biotic and abiotic reactions. Furthermore, results from reactors prepared with acetylene (a potent, reversible inhibitor of reductive dehalogenases (1)) will be presented as a means of identifying the enzymes involved in the transformation of CT. The results clearly demonstrate that reductive dechlorination of CT can be promoted by anaerobic cultures not previously acclimated to CT. 1. G. Pon, M. R. Hyman, L. Semprini, Environ. Sci. Technol. 37, 3181-3188 (2003).

Biodegradation of the artificial sweetener acesulfame in biological wastewater treatment and sandfilters.

PubMed

Castronovo, Sandro; Wick, Arne; Scheurer, Marco; Nödler, Karsten; Schulz, Manoj; Ternes, Thomas A

2017-03-01

A considerable removal of the artificial sweetener acesulfame (ACE) was observed during activated sludge processes at 13 wastewater treatment plants (WWTPs) as well as in a full-scale sand filter of a water works. A long-term sampling campaign over a period of almost two years revealed that ACE removal in WWTPs can be highly variable over time. Nitrifying/denitrifying sequencing batch reactors (SBR) as well as aerobic batch experiments with activated sludge and filter sand from a water works confirmed that both activated sludge as well as filter sand can efficiently remove ACE and that the removal can be attributed to biologically mediated degradation processes. The lab results strongly indicated that varying ACE removal in WWTPs is not associated with nitrification processes. Neither an enhancement of the nitrification rate nor the availability of ammonium or the inhibition of ammonium monooxygenase by N-allylthiourea (ATU) affected the degradation. Moreover, ACE was found to be also degradable by activated sludge under denitrifying conditions, while being persistent in the absence of both dissolved oxygen and nitrate. Using ion chromatography coupled with high resolution mass spectrometry, sulfamic acid (SA) was identified as the predominant transformation product (TP). Quantitative analysis of ACE and SA revealed a closed mass balance during the entire test period and confirmed that ACE was quantitatively transformed to SA. Measurements of dissolved organic carbon (DOC) revealed an almost complete removal of the carbon originating from ACE, thereby further confirming that SA is the only relevant final TP in the assumed degradation pathway of ACE. A first analysis of SA in three municipal WWTP revealed similar concentrations in influents and effluents with maximum concentrations of up to 2.3 mg/L. The high concentrations of SA in wastewater are in accordance with the extensive use of SA in acid cleaners, while the degradation of ACE in WWTPs adds only a very small portion of the total load of SA discharged into surface waters. No removal of SA was observed by the biological treatment applied at these WWTPs. Moreover, SA was also stable in the aerobic batch experiments conducted with the filter sand from a water works. Hence, SA might be a more appropriate wastewater tracer than ACE due to its chemical and microbiological persistence, the negligible sorbing affinity (high negative charge density) and its elevated concentrations in WWTP effluents. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Sludge settling processes in SBR-related sewage treatment plants according to the Biocos method.

PubMed

Meusel, S; Englert, R

2004-01-01

This paper describes the investigations in a sedimentation and circulation reactor (SU-reactor) of a three-phase Biocos plant. The aim of these investigations was the determination of the temporal and depth-dependent distribution of suspended solid contents, as well as describing the sludge sedimentation curves. The calculated results reveal peculiarities of the Biocos method with regard to sedimentation processes. In the hydraulically uninterrupted (pre-)settling phase, a sludge level depth was observed, which remained constant over the reactor surface and increased linearly according to the sludge volume. The settling and the thickening processes of this phase corresponded to a large extent to the well-known settling test in a one-litre measuring cylinder. During the discharge phase, the investigated settling rate was overlaid by the surface loading rate and the sludge level changed depending on the difference between those two parameters. The solid distribution of the A-phase indicated a formation of functional zones, which were influenced by the surface loading. The formation was comparable to the formation of layers in secondary settling tanks with vertical flow. The concentration equalisation between the biological reactor and the SU-reactor proved to be problematic during the circulation phase, because a type of internal sludge circulation occurred in the SU-reactor. A permanent sludge recirculation seems to be highly recommendable.

Synergistic effect of nano calcium carbonate (NCC)/carbon black (CB) on the cure characteristics and physico-mechanical properties of NR/SBR blends

NASA Astrophysics Data System (ADS)

Mamauod, Siti Nur Liyana; Romli, Ahmad Zafir; Rizuan, Mohd Ismail Rifdi

2017-09-01

This research was carried out as to develop hybrid filler reinforced into the blend of natural rubber (NR) and styrene butadiene rubber (SBR). The NR/SBR blend was reinforced using carbon black (CB) and nano calcium carbonate (NCC). The NCC content varied from 2-10 phr which was incorporated into the NR/SBR blend filled with fixed 50 phr of CB. The main aim of this project was to study the synergistic effect of NCC and CB reinforced NR/SBR blends towards the curing characteristics using cure rheometer, the viscosity of uncured NR/SBR compounds, physical and mechanical property blends. From the results obtained, the optimum ratio of blending was identified at 4 phr of NCC loading. Tensile strength, elongation at break, modulus and hardness increased progressively with increasing the NCC loading from 0 phr up to a maximum value at 4 phr. This increment occurs due to consolidation of the network structure of the polymer chains with the increasing NCC content. Up to the optimum amount of NCC, the tendency for NCC particles to form aggregate was very high and hence reduces the properties of rubber blends. It proved that NCC acts as a co-reinforcing agent for CB to improve the performance in the NR/SBR blends.

pH-oscillations in the bromate-sulfite reaction in semibatch and in gel-fed batch reactors

NASA Astrophysics Data System (ADS)

Poros, Eszter; Kurin-Csörgei, Krisztina; Szalai, István; Rábai, Gyula; Orbán, Miklós

2015-06-01

The simplest bromate oxidation based pH-oscillator, the two component BrO3--SO32- flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH˜3), long lasting (11-24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na2SO3 and H2SO4 was pumped into the solution of BrO3- with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na2SO3. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO3--SO32- pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications.

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover.

PubMed

Xu, Fuqing; Shi, Jian; Lv, Wen; Yu, Zhongtang; Li, Yebo

2013-01-01

Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5L/kg VS(feed), while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6L/kg VS(feed). The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3g CaCO(3)/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents. Copyright © 2012 Elsevier Ltd. All rights reserved.

A novel approach of solid waste management via aromatization using multiphase catalytic pyrolysis of waste polyethylene.

PubMed

Gaurh, Pramendra; Pramanik, Hiralal

2018-01-01

A new and innovative approach was adopted to increase the yield of aromatics like, benzene, toluene and xylene (BTX) in the catalytic pyrolysis of waste polyethylene (PE). The BTX content was significantly increased due to effective interaction between catalystZSM-5 and target molecules i.e., lower paraffins within the reactor. The thermal and catalytic pyrolysis both were performed in a specially designed semi-batch reactor at the temperature range of 500 °C-800 °C. Catalytic pyrolysis were performed in three different phases within the reactor batch by batch systematically, keeping the catalyst in A type- vapor phase, B type- liquid phase and C type- vapor and liquid phase (multiphase), respectively. Total aromatics (BTX) of 6.54 wt% was obtained for thermal pyrolysis at a temperature of 700 °C. In contrary, for the catalytic pyrolysis A, B and C types reactor arrangement, the aromatic (BTX) contents were progressively increased, nearly 6 times from 6.54 wt% (thermal pyrolysis) to 35.06 wt% for C-type/multiphase (liquid and vapor phase). The pyrolysis oil were characterized using GC-FID, FT-IR, ASTM distillation and carbon residue test to evaluate its end use and aromatic content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of iron ions and electric field on nitrification process in the periodic reversal bio-electrocoagulation system.

PubMed

Qian, Guangsheng; Hu, Xiaomin; Li, Liang; Ye, Linlin; Lv, Weijian

2017-11-01

This study explored the nitrification mechanism of a periodic reversal bio-electrocoagulation system with Fe-C electrodes. The ammonia nitrogen removal was compared in four identical cylindrical sequencing bath reactors. Two of them were reactors with Fe-C electrodes (S1) and C-C electrodes (S2), respectively. The other two were a reactor with iron ions (S3) and a traditional SBR (S4), respectively. The results demonstrated that the effect on enhancing nitrification in S1 was the best among all four SBRs, followed by S3, S2 and S4. Iron ions increased the biomass, and electric field improved the proton transfer and enzyme activity. The dominant bacterial genera in the four SBRs were Hyphomicrobium, Thauera, Nitrobacter, Nitrosomonas, Paracoccus and Hydrogenophaga. The iron ions may increase the levels of Nitrosomonas and Nitrobacter, both of which were the main microbes of the nitrification process. This study provided a significant and meaningful understanding of nitrification in a bio-electrocoagulation system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acceptance Test Data for BWXT Coated Particle Batches 93172B and 93173B—Defective IPyC and Pyrocarbon Anisotropy

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

Hunn, John D.; Helmreich, Grant W.; Dyer, John A.

Coated particle batches J52O-16-93172B and J52O-16-93173B were produced by Babcock and Wilcox Technologies (BWXT) as part of the production campaign for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR), but were not used in the final fuel composite. However, these batches may be used as demonstration production-scale coated particle fuel for other experiments. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT lot J52R-16-69317 containing a mixture ofmore » 15.5%-enriched uranium carbide and uranium oxide (UCO). The TRISO coatings consisted of four consecutive CVD layers: a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. The TRISO-coated particle batches were sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batches were designated by appending the letter A to the end of the batch number (e.g., 93172A). Secondary upgrading by sieving was performed on the A-designated batches to remove particles with missing or very-thin buffer layers that were identified during previous analysis of the individual batches for defective IPyC, as reported in the acceptance test data report for the AGR-5/6/7 production batches [Hunn et al. 2017b]. The additionally-upgraded batches were designated by appending the letter B to the end of the batch number (e.g., 93172B).« less

Characterization of metal adsorption kinetic properties in batch and fixed-bed reactors.

PubMed

Chen, J Paul; Wang, Lin

2004-01-01

Copper adsorption kinetic properties in batch and fixed-bed reactors were studied in this paper. The isothermal adsorption experiments showed that the copper adsorption capacity of a granular activated carbon (Filtrasorb 200) increased when ionic strength was higher. The presence of EDTA diminished the adsorption. An intraparticle diffusion model and a fixed-bed model were successfully used to describe the batch kinetic and fixed-bed operation behaviors. The kinetics became faster when the solution pH was not controlled, implying that the surface precipitation caused some metal uptake. The external mass transfer coefficient, the diffusivity and the dispersion coefficient were obtained from the modeling. It was found that both external mass transfer and dispersion coefficients increased when the flow rate was higher. Finally effects of kinetic parameters on simulation of fixed-bed operation were conducted.

Morphology and vulcanizate properties of ethylene-propylene-diene rubber/ styrene-butadiene rubber blends.

PubMed

Park, Gayoung; Kim, Yun Hee; Kim, Dong Soo; Ko, Young Chun

2010-05-01

Morphology and vulcanizate properties of EPDM/SBR blends were investigated. AAHR (a mixture of aliphatic and aromatic hydrocarbon resins) was used as a compatibilizer and bis(3-triethoxysilylpropyl)tetrasulfide (TESPT) was used as a coupling agent. The vulcanizate properties and the morphological studies revealed that EPDM and SBR were incompatible, and the addition of AAHR was very effective to enhance the compatibility between EPDM and SBR. The weight percent of bound rubbers was increased with increasing SBR contents. The addition of an AAHR increased the amounts of bound rubbers, and hence the vulcanizate properties such as tear strength and fatigue resistance of the EPDM/SBR blends were improved. The dynamic mechanical analysis and the morphological studies revealed that the addition of TESPT increased the weight of bound rubbers and provided better dispersion of carbon black, resulting in good mechanical properties such as tear strength and fatigue resistance of the vulcanized EPDM/SBR blends. The smaller particle of zinc oxide (i.e., 50 nm > 100 nm > 1000 nm) yielded to the better blending properties of the polymer blend.

Rheological properties of styrene-butadiene rubber filled with electron beam modified surface treated dual phase fillers

NASA Astrophysics Data System (ADS)

Shanmugharaj, A. M.; Bhowmick, Anil K.

2004-01-01

The rheological properties of styrene-butadiene rubber (SBR) loaded with dual phase filler were measured using Monsanto Processability Tester (MPT) at three different temperatures (100°C, 110°C and 130°C) and four different shear rates (61.3, 306.3, 613, and 1004.5 s -1). The effect of electron beam modification of dual phase filler in absence and presence of trimethylol propane triacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) on melt flow properties of SBR was also studied. The viscosity of all the systems decreases with shear rate indicating their pseudoplastic or shear thinning nature. The higher shear viscosity for the SBR loaded with the electron beam modified filler is explained in terms of variation in structure of the filler upon electron beam irradiation. Die swell of the modified filler loaded SBR is slightly higher than that of the unmodified filler loaded rubber, which is explained by calculating normal stress difference for the systems. Activation energy of the modified filler loaded SBR systems is also slightly higher than that of the control filler loaded SBR system.

Flow optimization study of a batch microfluidics PET tracer synthesizing device

PubMed Central

Elizarov, Arkadij M.; Meinhart, Carl; van Dam, R. Michael; Huang, Jiang; Daridon, Antoine; Heath, James R.; Kolb, Hartmuth C.

2010-01-01

We present numerical modeling and experimental studies of flow optimization inside a batch microfluidic micro-reactor used for synthesis of human-scale doses of Positron Emission Tomography (PET) tracers. Novel techniques are used for mixing within, and eluting liquid out of, the coin-shaped reaction chamber. Numerical solutions of the general incompressible Navier Stokes equations along with time-dependent elution scalar field equation for the three dimensional coin-shaped geometry were obtained and validated using fluorescence imaging analysis techniques. Utilizing the approach presented in this work, we were able to identify optimized geometrical and operational conditions for the micro-reactor in the absence of radioactive material commonly used in PET related tracer production platforms as well as evaluate the designed and fabricated micro-reactor using numerical and experimental validations. PMID:21072595

The kinetics, current efficiency, and power consumption of electrochemical dye decolorization by BD-NCD film electrode

NASA Astrophysics Data System (ADS)

Nurhayati, Ervin; Juang, Yaju; Huang, Chihpin

2017-06-01

Diamond film electrode has been known as a material with very wide potential window for water electrolysis which leads to its applicability in numerous electrochemical processes. Its capability to produce hydroxyl radicals, a very strong oxidants, prompts its popular application in wastewater treatment. Batch and batch recirculation reactor were applied to perform bulk electrolysis experiments to investigate the kinetics of dye decolorization under different operation conditions, such as pH, active species, and current density. Furthermore, COD degradation data from batch recirculation reactor operation was used as the basis for the calculation of current efficiency and power consumption in the decolorization process. The kinetics of decolorization process using boron-doped nanocrystalline diamond (BD-NCD) film electrode revealed that acidic condition is favored for the dye degradation, and the presence of chloride ion in the solution was found to be more advantageous than sulfate active species, as evidenced by the higher reaction rate constants. Applying different current density of 10, 20 and 30 mA cm-2, it was found that the higher the current density the faster the decolorization rate. General current efficiency achieved after nearly total decolorization and 80% COD removal in batch recirculation reactor was around 74%, with specific power consumption of 4.4 kWh m-3 (in terms of volume of solution treated) or 145 kWh kg-1(in terms of kg COD treated).

Development of Realistic Striatal Digital Brain (SDB) Phantom for 123I-FP-CIT SPECT and Effect on Ventricle in the Brain for Semi-quantitative Index of Specific Binding Ratio.

PubMed

Furuta, Akihiro; Onishi, Hideo; Nakamoto, Kenta

This study aimed at developing the realistic striatal digital brain (SDB) phantom and to assess specific binding ratio (SBR) for ventricular effect in the 123 I-FP-CIT SPECT imaging. SDB phantom was constructed in to four segments (striatum, ventricle, brain parenchyma, and skull bone) using Percentile method and other image processing in the T2-weighted MR images. The reference image was converted into 128×128 matrixes to align MR images with SPECT images. The process image was reconstructed with projection data sets generated from reference images additive blurring, attenuation, scatter, and statically noise. The SDB phantom was evaluated to find the accuracy of calculated SBR and to find the effect of SBR with/without ventricular counts with the reference and process images. We developed and investigated the utility of the SDB phantom in the 123 I-FP-CIT SPECT clinical study. The true value of SBR was just marched to calculate SBR from reference and process images. The SBR was underestimated 58.0% with ventricular counts in reference image, however, was underestimated 162% with ventricular counts in process images. The SDB phantom provides an extremely convenient tool for discovering basic properties of 123 I-FP-CIT SPECT clinical study image. It was suggested that the SBR was susceptible to ventricle.

Bromelain Inhibits Allergic Sensitization and Murine Asthma via Modulation of Dendritic Cells

PubMed Central

Secor, Eric R.; Szczepanek, Steven M.; Castater, Christine A.; Adami, Alexander J.; Matson, Adam P.; Rafti, Ektor T.; McNamara, Jeffrey T.; Schramm, Craig M.; Thrall, Roger S.; Silbart, Lawrence K.

2013-01-01

The incidence of atopic conditions has increased in industrialized countries. Persisting symptoms and concern for drug side-effects lead patients toward adjunctive treatments such as phytotherapy. Previously, we have shown that Bromelain (sBr), a mixture of cysteine proteases from pineapple, Ananas comosus, inhibits ovalbumin (OVA)-induced murine model of allergic airway disease (AAD). However, sBr's effect on development of AAD when treatment is administered throughout OVA-alum sensitization was unknown and is the aim of the present study. C57BL/6J mice were sensitized with OVA/alum and challenged with 7 days OVA aerosol. sBr 6 mg/kg/0.5 ml or PBS vehicle were administered throughout sensitization. Lung, bronchoalveolar lavage (BAL), spleen, and lymph nodes were processed for flow cytometry and OVA-specific IgE was determined via ELISA. sBr treatment throughout OVA-alum sensitization significantly reduced the development of AAD (BAL eosinophils and lymphocytes). OVA-specific IgE and OVA TET+ cells were decreased. sBr reduced CD11c+ dendritic cell subsets, and in vitro treatment of DCs significantly reduced CD44, a key receptor in both cell trafficking and activation. sBr was shown to reduce allergic sensitization and the generation of AAD upon antigen challenge. These results provide additional insight into sBr's anti-inflammatory and antiallergic properties and rationale for translation into the clinical arena. PMID:24381635

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

Investigation of Poultry Waste for Anaerobic Digestion: A Case Study

NASA Astrophysics Data System (ADS)

Salam, Christopher R.

Anaerobic Digestion (AD) is a biological conversion technology which is being used to produce bioenergy all over the world. This energy is created from biological feedstocks, and can often use waste products from various food and agricultural processors. Biogas from AD can be used as a fuel for heating or for co-generation of electricity and heat and is a renewable substitute to using fossil fuels. Nutrient recycling and waste reduction are additional benefits, creating a final product that can be used as a fertilizer in addition to energy benefits. This project was conducted to investigate the viability of three turkey production wastes as AD feedstock: two turkey litters and a material separated from the turkey processing wastewater using dissolved air flotation (DAF) process. The DAF waste contained greases, oils and other non-commodity portions of the turkey. Using a variety of different process methods, types of bacteria, loading rates and food-to-microorganism ratios, optimal loading rates for the digestion of these three materials were obtained. In addition, the co-digestion of these materials revealed additional energy benefits. In this study, batch digestion tests were carried out to treat these three feedstocks, using mesophilic and thermophilic bacteria, using loading rates of 3 and 6 gVS/L They were tested separately and also as a mixture for co-digestion. The batch reactor used in this study had total and working volumes of 1130 mL and 500 mL, respectively. The initial organic loading was set to be 3 gVS/L, and the food to microorganism ratio was either 0.6 or 1.0 for different treatments based on the characteristics of each material. Only thermophilic (50 +/- 2ºC) temperatures were tested for the litter and DAF wastes in continuous digestion, but mesophilic and thermophilic batch digestion experiments were conducted. The optimum digestion time for all experiments was 14 days. The biogas yields of top litter, mixed litter, and DAF waste under mesophilic batch conditions all at 3 gVS/L loading were determined to be 148.6 +/- 7.82, 176.5 +/- 11.1 and 542.0 +/- 37.9 mL/ gVS, respectively and were 201.9 +/- 10.0, 210.4 +/- 29.3, and 419.3 +/- 12.1 mL/gVS, respectively, for initial loading of 6 gVS/L. Under thermophilic batch conditions, the top litter, mixed litter, and DAF waste had the biogas yields of 255.3 +/- 7.9, 313.4 +/- 30.1and 297.4 +/- 33.8 mL/gVS for loading rate of 3 gVS/L and 233.8 +/- 45.3, 306.5 +/- 11.8 and 185.1 +/- 0.85 mL/gVS for loading rate of 6 gVS/L. The biogas yields from co-digestion of the mixed litter and DAF waste at 3 gVS/L were 461.8 +/- 41.3 mL/gVS under thermophilic conditions. The results from batch anaerobic digestion tests were then used for designing continuous digestion experiments. All the continuous digestion experiments were conducted by using an Anaerobic Phase Solids (APS) digester system operated at a thermophilic temperature. The total volume of the continuous digester system was 4.8 L and the working volume was around 4.4 L. The APS digester system had two hydrolysis reactors and one biogasification reactor. Feedstock was loaded into the hydrolysis reactors in batches. The feedstock digestion time was 14 days and the average organic loading rate (OLR) of the system was 3 gVS/L/day. The experiment has three distinct feedstock stages, first with turkey litter waste, a co-digestion of DAF and turkey litter waste, followed by DAF waste. The biogas yields were determined to be 305.2 +/- 70.6 mL/gVS/d for turkey mixed litter, 455.8 +/- 77.2 mL/gVS/d during the mixture of mixed litter and DAF waste, and 382.0 +/- 39.6 mL/gVS for DAF waste. The biogas yields from the thermophilic batch test yields compare with that of the continuous digester yields. For experiments utilizing turkey litter, batch tests yielded 313.4 +/- 30.1mL/gVS biogas and 305.2 +/- 70.6 mL/gVS/d for continuous experiments. For experiments using codigestion of turkey litter and DAF waste, batches yielded 461.8 +/- 41.3 mL/gVS biogas comparing well to continuous digester operation that yielded 455.8 +/- 77.2 mL/gVS/d. It was mainly in the case for DAF that batch vs. continuous digester testing yielded a significant difference in performance. For experiments using DAF waste, batches yielded 297.4 +/- 33.8 mL/gVS biogas and continuous digester operation yielded 455.8 +/- 77.2 mL/gVS/d. For a case study on the APS digester system, mesophilic DAF waste was chosen as the optimum substrate. Using this material and reactor condition, a case study was built using provided information and experimental results to build a simulation. A reactor site needed to process 11,800 kgVS of DAF waste would require 4,800 m3 of tank volume, and use nearly 4,000 m3 as working volume. This reactor was modeled after a 2 stage APS reactor, with 2 hydrolysis reactors and 1 biogasification reactor, and had a 14 day retention time and a 3 gVS/L/d organic loading rate. The expected biogas output was 550 mL/gVS, and expected waste reduction was 20%. The reactor would produce 7,113 m3/d of biogas, and would be burned for 127,223 MJ/d.

PROCESS INTENSIFICATION: OXIDATION OF BENZYL ALCOHOL USING A CONTINUOUS ISOTHERMAL REACTOR UNDER MICROWAVE IRRADIATION

EPA Science Inventory

In the past two decades, several investigations have been carried out using microwave radiation for performing chemical transformations. These transformations have been largely performed in conventional batch reactors with limited mixing and heat transfer capabilities. The reacti...

Performance and life cycle environmental benefits of recycling spent ion exchange brines by catalytic treatment of nitrate.

PubMed

Choe, Jong Kwon; Bergquist, Allison M; Jeong, Sangjo; Guest, Jeremy S; Werth, Charles J; Strathmann, Timothy J

2015-09-01

Salt used to make brines for regeneration of ion exchange (IX) resins is the dominant economic and environmental liability of IX treatment systems for nitrate-contaminated drinking water sources. To reduce salt usage, the applicability and environmental benefits of using a catalytic reduction technology to treat nitrate in spent IX brines and enable their reuse for IX resin regeneration were evaluated. Hybrid IX/catalyst systems were designed and life cycle assessment of process consumables are used to set performance targets for the catalyst reactor. Nitrate reduction was measured in a typical spent brine (i.e., 5000 mg/L NO3(-) and 70,000 mg/L NaCl) using bimetallic Pd-In hydrogenation catalysts with variable Pd (0.2-2.5 wt%) and In (0.0125-0.25 wt%) loadings on pelletized activated carbon support (Pd-In/C). The highest activity of 50 mgNO3(-)/(min - g(Pd)) was obtained with a 0.5 wt%Pd-0.1 wt%In/C catalyst. Catalyst longevity was demonstrated by observing no decrease in catalyst activity over more than 60 days in a packed-bed reactor. Based on catalyst activity measured in batch and packed-bed reactors, environmental impacts of hybrid IX/catalyst systems were evaluated for both sequencing-batch and continuous-flow packed-bed reactor designs and environmental impacts of the sequencing-batch hybrid system were found to be 38-81% of those of conventional IX. Major environmental impact contributors other than salt consumption include Pd metal, hydrogen (electron donor), and carbon dioxide (pH buffer). Sensitivity of environmental impacts of the sequencing-batch hybrid reactor system to sulfate and bicarbonate anions indicate the hybrid system is more sustainable than conventional IX when influent water contains <80 mg/L sulfate (at any bicarbonate level up to 100 mg/L) or <20 mg/L bicarbonate (at any sulfate level up to 100 mg/L) assuming 15 brine reuse cycles. The study showed that hybrid IX/catalyst reactor systems have potential to reduce resource consumption and improve environmental impacts associated with treating nitrate-contaminated water sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantitation of specific binding ratio in 123I-FP-CIT SPECT: accurate processing strategy for cerebral ventricular enlargement with use of 3D-striatal digital brain phantom.

PubMed

Furuta, Akihiro; Onishi, Hideo; Amijima, Hizuru

2018-06-01

This study aimed to evaluate the effect of ventricular enlargement on the specific binding ratio (SBR) and to validate the cerebrospinal fluid (CSF)-Mask algorithm for quantitative SBR assessment of 123 I-FP-CIT single-photon emission computed tomography (SPECT) images with the use of a 3D-striatum digital brain (SDB) phantom. Ventricular enlargement was simulated by three-dimensional extensions in a 3D-SDB phantom comprising segments representing the striatum, ventricle, brain parenchyma, and skull bone. The Evans Index (EI) was measured in 3D-SDB phantom images of an enlarged ventricle. Projection data sets were generated from the 3D-SDB phantoms with blurring, scatter, and attenuation. Images were reconstructed using the ordered subset expectation maximization (OSEM) algorithm and corrected for attenuation, scatter, and resolution recovery. We bundled DaTView (Southampton method) with the CSF-Mask processing software for SBR. We assessed SBR with the use of various coefficients (f factor) of the CSF-Mask. Specific binding ratios of 1, 2, 3, 4, and 5 corresponded to SDB phantom simulations with true values. Measured SBRs > 50% that were underestimated with EI increased compared with the true SBR and this trend was outstanding at low SBR. The CSF-Mask improved 20% underestimates and brought the measured SBR closer to the true values at an f factor of 1.0 despite an increase in EI. We connected the linear regression function (y = - 3.53x + 1.95; r = 0.95) with the EI and f factor using root-mean-square error. Processing with CSF-Mask generates accurate quantitative SBR from dopamine transporter SPECT images of patients with ventricular enlargement.

Gut microbial diversity is reduced and is associated with colonic inflammation in a piglet model of short bowel syndrome

PubMed Central

Lapthorne, Susan; Pereira-Fantini, Prue M.; Fouhy, Fiona; Wilson, Guineva; Thomas, Sarah L.; Dellios, Nicole L.; Scurr, Michelle; O’Sullivan, Orla; Ross, R. Paul; Stanton, Catherine; Fitzgerald, Gerald F.; Cotter, Paul D.; Bines, Julie E.

2013-01-01

Background and objectives Following small bowel resection (SBR), the luminal environment is altered, which contributes to clinical manifestations of short bowel syndrome (SBS) including malabsorption, mucosal inflammation and bacterial overgrowth. However, the impact of SBR on the colon has not been well-defined. The aims of this study were to characterize the colonic microbiota following SBR and to assess the impact of SBR on mucosal inflammation in the colon. Results Analysis of the colonic microbiota demonstrated that there was a significant level of dysbiosis both two and six weeks post-SBR, particularly in the phylum Firmicutes, coupled with a decrease in overall bacterial diversity in the colon. This decrease in diversity was associated with an increase in colonic inflammation six weeks post-surgery. Methods Female (4-week old) piglets (5−6/group) received a 75% SBR, a transection (sham) or no surgery. Compositional analysis of the colonic microbiota was performed by high-throughput sequencing, two- and six-weeks post-surgery. The gene expression of the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, IL-8, IL-18 and tumor necrosis factor (TNF)-α in the colonic mucosa was assessed by qRT-PCR and the number of macrophages and percentage inducible nitric oxide synthase (iNOS) staining in the colonic epithelium were quantified by immunohistochemistry. Conclusions SBR significantly decreased the diversity of the colonic microbiota and this was associated with an increase in colonic mucosal inflammation. This study supports the hypothesis that SBR has a significant impact on the colon and that this may play an important role in defining clinical outcome. PMID:23549027

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.

Bioconversion of waste office paper to hydrogen using pretreated rumen fluid inoculum.

PubMed

Botta, Lívia Silva; Ratti, Regiane Priscila; Sakamoto, Isabel Kimiko; Ramos, Lucas Rodrigues; Silva, Edson Luiz; Varesche, Maria Bernadete Amâncio

2016-12-01

In this study, a microbial consortium from an acid-treated rumen fluid was used to improve the yields of H 2 production from paper residues in batch reactors. The anaerobic batch reactors, which contained paper and cellulose, were operated under three conditions: (1) 0.5 g paper/L, (2) 2 g paper/L, and (3) 4 g paper/L. Cellulase was added to promote the hydrolysis of paper to soluble sugars. The H 2 yields were 5.51, 4.65, and 3.96 mmol H 2 /g COD, respectively, with substrate degradation ranging from 56 to 65.4 %. Butyric acid was the primary soluble metabolite in the three reactors, but pronounced solventogenesis was detected in the reactors incubated with increased paper concentrations (2.0 and 4.0 g/L). A substantial prevalence of Clostridium acetobutylicum (99 % similarity) was observed in the acid-treated rumen fluid, which has been recognized as an efficient H 2 -producing strain in addition to ethanol and n-butanol which were also detected in the reactors.

Latex improvement of recycled asphalt pavement

NASA Astrophysics Data System (ADS)

Drennon, C.

1982-08-01

The performance of a single unmodified milled recycled asphalt concrete was compared to milled asphalt concrete modified by addition of three types of rubber latex. Latex was added at 2, 3, 5, and 8 percent latex by weight of asphalt in the asphalt concrete. Lattices used were a styrene butadiene (SBR), a natural rubber (NR), an acrylonitrile butadiene (NBR), and four varieties of out of specification SBR lattices. Marshall tests, while indecisive, showed a modest improvement in properties of SBR and NR added material at 3 and 5 percent latex. Addition of NBR latex caused deterioration in Marshall stability and flow over that of control. Repeated load tests were run using the indirect tensile test, analyzed by the VESYS program, which computes life of pavements. Repeated load tests showed improvement in asphalt concrete life when 3 and 5 percent SBR was added. Improvement was also shown by the out of specification SBR.

A subagging regression method for estimating the qualitative and quantitative state of groundwater

NASA Astrophysics Data System (ADS)

Jeong, J.; Park, E.; Choi, J.; Han, W. S.; Yun, S. T.

2016-12-01

A subagging regression (SBR) method for the analysis of groundwater data pertaining to the estimation of trend and the associated uncertainty is proposed. The SBR method is validated against synthetic data competitively with other conventional robust and non-robust methods. From the results, it is verified that the estimation accuracies of the SBR method are consistent and superior to those of the other methods and the uncertainties are reasonably estimated where the others have no uncertainty analysis option. To validate further, real quantitative and qualitative data are employed and analyzed comparatively with Gaussian process regression (GPR). For all cases, the trend and the associated uncertainties are reasonably estimated by SBR, whereas the GPR has limitations in representing the variability of non-Gaussian skewed data. From the implementations, it is determined that the SBR method has potential to be further developed as an effective tool of anomaly detection or outlier identification in groundwater state data.

Morphological and mechanical properties of styrene butadiene rubber/nano copper nanocomposites

NASA Astrophysics Data System (ADS)

Harandi, Maryam Hadizadeh; Alimoradi, Fakhrodin; Rowshan, Gholamhussein; Faghihi, Morteza; Keivani, Maryam; Abadyan, Mohamadreza

In this research, rubber based nanocomposites with presence of nanoparticle has been studied. Styrene butadiene rubber (SBR)/nanocopper (NC) composites were prepared using two-roll mill method. Transmission electron microscope (TEM) and scanning electron microscope (SEM) images showed proper dispersion of NC in the SBR matrix without substantial agglomeration of nanoparticles. To evaluate the curing properties of nanocomposite samples, swelling and cure rheometric tests were conducted. Moreover, the rheological studies were carried out over a range of shear rates. The effect of NC particles was examined on the thermal behavior of the SBR using thermal gravimetric analysis (TGA). Furthermore, tensile tests were employed to investigate the capability of nanoparticles to enhance mechanical behavior of the compounds. The results showed enhancement in tensile properties with incorporation of NC to SBR matrix. Moreover, addition of NC increased shear viscosity and curing time of SBR composites.

Mechanical behaviour study on SBR/EVA composite for FDM feedstock fabrication

NASA Astrophysics Data System (ADS)

Raveverma, P.; Ibrahim, M.; Sa'ude, N.; Yarwindran, M.; Nasharuddin, M.

2017-04-01

This paper presents the research development of a new SBR/EVA composite flexible feedstock material by the injection moulding machine. The material consists of poly (ethylene-co-vinyl acetate) in styrene butadiene rubber cross-linked by Dicumyl Peroxide. In this study, the mechanical behaviour of injection moulded SBR/EVA composite with different blend ratio investigated experimentally. The formulations of blend ratio with several combinations of a new SBR/EVA flexible feedstock was done by volume percentage (vol. %). Based on the result obtained from the mechanical testing done which is tensile and hardness the composite of SBR/EVA has the high potency to be fabricated as the flexible filament feedstock. The ratio of 80:20 which as an average hardness and tensile strength proved to be the suitable choice to be fabricated as the flexible filament feedstock. The study has reached its goals on the fabricating and testing a new PMC which is flexible.

Anaerobic Biodegradation Of Methyl tert-Butyl Ether Under Iron-Reducing Conditions In Batch And Continuous-Flow Cultures

EPA Science Inventory

The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing...

Microalgae-mediated bioremediation and valorization of cattle wastewater previously digested in a hybrid anaerobic reactor using a photobioreactor: Comparison between batch and continuous operation.

PubMed

de Mendonça, Henrique Vieira; Ometto, Jean Pierre Henry Balbaud; Otenio, Marcelo Henrique; Marques, Isabel Paula Ramos; Dos Reis, Alberto José Delgado

2018-08-15

Scenedesmus obliquus (ACOI 204/07) microalgae were cultivated in cattle wastewater in vertical alveolar flat panel photobioreactors, operated in batch and continuous mode, after previous digestion in a hybrid anaerobic reactor. In batch operation, removal efficiencies ranges of 65 to 70% of COD, 98 to 99% of NH 4 + and 69 to 77.5% of PO 4 -3 after 12days were recorded. The corresponding figures for continuous flow were from 57 to 61% of COD, 94 to 96% of NH 4 + and 65 to 70% of PO 4 -3 with mean hidraulic retention time of 12days. Higher rates of CO 2 fixation (327-547mgL -1 d -1 ) and higher biomass volumetric productivity (213-358mgL -1 d -1 ) were obtained in batch mode. This microalgae-mediated process can be considered promising for bioremediation and valorization of effluents produced by cattle breeding yielding a protein-rich microalgal biomass that could be eventually used as cattle feed. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous hydrogen utilization and in situ biogas upgrading in an anaerobic reactor.

PubMed

Luo, Gang; Johansson, Sara; Boe, Kanokwan; Xie, Li; Zhou, Qi; Angelidaki, Irini

2012-04-01

The possibility of converting hydrogen to methane and simultaneous upgrading of biogas was investigated in both batch tests and fully mixed biogas reactor, simultaneously fed with manure and hydrogen. Batch experiments showed that hydrogen could be converted to methane by hydrogenotrophic methanogenesis with conversion of more than 90% of the consumed hydrogen to methane. The hydrogen consumption rates were affected by both P(H₂) (hydrogen partial pressure) and mixing intensity. Inhibition of propionate and butyrate degradation by hydrogen (1 atm) was only observed under high mixing intensity (shaking speed 300 rpm). Continuous addition of hydrogen (flow rate of 28.6 mL/(L/h)) to an anaerobic reactor fed with manure, showed that more than 80% of the hydrogen was utilized. The propionate and butyrate level in the reactor was not significantly affected by the hydrogen addition. The methane production rate of the reactor with H₂ addition was 22% higher, compared to the control reactor only fed with manure. The CO₂ content in the produced biogas was only 15%, while it was 38% in the control reactor. However, the addition of hydrogen resulted in increase of pH (from 8.0 to 8.3) due to the consumption of bicarbonate, which subsequently caused slight inhibition of methanogenesis. Copyright © 2011 Wiley Periodicals, Inc.

Hybrid Nitrous Oxide Production from a Partial Nitrifying Bioreactor: Hydroxylamine Interactions with Nitrite.

PubMed

Terada, Akihiko; Sugawara, Sho; Hojo, Keisuke; Takeuchi, Yuki; Riya, Shohei; Harper, Willie F; Yamamoto, Tomoko; Kuroiwa, Megumi; Isobe, Kazuo; Katsuyama, Chie; Suwa, Yuichi; Koba, Keisuke; Hosomi, Masaaki

2017-03-07

The goal of this study was to elucidate the mechanisms of nitrous oxide (N 2 O) production from a bioreactor for partial nitrification (PN). Ammonia-oxidizing bacteria (AOB) enriched from a sequencing batch reactor (SBR) were subjected to N 2 O production pathway tests. The N 2 O pathway test was initiated by supplying an inorganic medium to ensure an initial NH 4 + -N concentration of 160 mg-N/L, followed by 15 NO 2 - (20 mg-N/L) and dual 15 NH 2 OH (each 17 mg-N/L) spikings to quantify isotopologs of gaseous N 2 O ( 44 N 2 O, 45 N 2 O, and 46 N 2 O). N 2 O production was boosted by 15 NH 2 OH spiking, causing exponential increases in mRNA transcription levels of AOB functional genes encoding hydroxylamine oxidoreductase (haoA), nitrite reductase (nirK), and nitric oxide reductase (norB) genes. Predominant production of 45 N 2 O among N 2 O isotopologs (46% of total produced N 2 O) indicated that coupling of 15 NH 2 OH with 14 NO 2 - produced N 2 O via N-nitrosation hybrid reaction as a predominant pathway. Abiotic hybrid N 2 O production was also observed in the absence of the AOB-enriched biomass, indicating multiple pathways for N 2 O production in a PN bioreactor. The additional N 2 O pathway test, where 15 NH 4 + was spiked into 400 mg-N/L of NO 2 - concentration, confirmed that the hybrid N 2 O production was a dominant pathway, accounting for approximately 51% of the total N 2 O production.

Relationship between soluble microbial products (SMP) and effluent organic matter (EfOM): characterized by fluorescence excitation emission matrix coupled with parallel factor analysis.

PubMed

Yu, Huarong; Qu, Fangshu; Sun, Lianpeng; Liang, Heng; Han, Zhengshuang; Chang, Haiqing; Shao, Senlin; Li, Guibai

2015-02-01

Effluent organic matter (EfOM) originating from wastewater treatment plant (WWTP) is of significant concern, as it not only influences the discharge quality of WWTP but also exerts a significant effect on the efficiency of the downstream advanced treatment facilities. Soluble microbial products (SMP) is a major part of EfOM. In order to further understand the relationship between soluble microbial products (SMP) and EfOM, and in turn, to propose measures for EfOM control, the formation of SMP and EfOM in identical activated sludge sequencing batch reactors (SBR) with different feed water was investigated using fluorescence excitation and emission spectroscopy matrix coupled with parallel factor analysis (EEM-PARAFAC) as well as other organic matter quantification tools. Results showed that EfOM contained not only SMP but also a considerable amount of allochthonous organic matter that derived not merely from natural organic matter (NOM). Four components in EfOM/SMP were identified by EEM-PARAFAC. Tyrosine-like substances in EfOM (Component 3, λex/em=270/316 nm) were mainly originated from utilization associated products (UAP) of SMP. Tryptophan-like substances (Component 2, λex/em=280/336 nm) as well as fulvic-like and humic-like substances in EfOM (Component 1, λex/em=240(290)/392 nm and Component 4, λex/em=260(365)/444 nm) were majorly derived from the refractory substances introduced along with the influent, among which Component 2 was stemmed from sources other than NOM. As solid retention time (SRT) increased, Component 2 and polysaccharides in SMP/EfOM decreased, while Component 4 in SMP increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treating low carbon/nitrogen (C/N) wastewater in simultaneous nitrification-endogenous denitrification and phosphorous removal (SNDPR) systems by strengthening anaerobic intracellular carbon storage.

PubMed

Wang, Xiaoxia; Wang, Shuying; Xue, Tonglai; Li, Baikun; Dai, Xian; Peng, Yongzhen

2015-06-15

A novel simultaneous nitrification denitrification and phosphorous removal-sequencing batch reactor (SNDPR-SBR) enriched with PAOs (phosphorus accumulating organisms), DPAOs (denitrifying PAOs), and GAOs (glycogen accumulating organisms) at the ratio of 2:1:1 was developed to achieve the simultaneous nutrient and carbon removal treating domestic wastewater with low carbon/nitrogen ratio (≤3.5). The SNDPR system was operated for 120 days at extended anaerobic stage (3 h) and short aerobic stage at low oxygen concentration (2.5 h) with short sludge retention time (SRT) of 10.9 d and hydraulic retention time (HRT) of 14.6 h. The results showed that at the stable operating stage, the average effluent chemical oxygen demand (COD) and PO4(3-)-P concentrations were 47.2 and 0.2 mg L(-1), respectively, the total nitrogen (TN) removal efficiency was 77.7%, and the SND efficiency reached 49.3%. Extended anaerobic stage strengthened the intracellular carbon (mainly poly-β-hydroxybutyrate, PHB) storage, efficiently utilized the organic substances in wastewater, and provided sufficient carbon sources for denitrification and phosphorus uptake without external carbon addition. Short aerobic stage at low oxygen concentration (dissolved oxygen (DO): 1 ± 0.3 mg L(-1)) achieved a concurrence of nitrification, endogenous denitrification, denitrifying and aerobic phosphorus uptake, and saved about 65% energy consumption for aeration. Microbial community analysis demonstrated that P removal was mainly performed by aerobic PAOs while N removal was mainly carried out by denitrifying GAOs (DGAOs), even though DPAOs were also participated in both N and P removal. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of pH on N2O production under aerobic conditions in a partial nitritation system.

PubMed

Law, Yingyu; Lant, Paul; Yuan, Zhiguo

2011-11-15

Ammonia-oxidising bacteria (AOB) are a major contributor to nitrous oxide (N(2)O) emissions during nitrogen transformation. N(2)O production was observed under both anoxic and aerobic conditions in a lab-scale partial nitritation system operated as a sequencing batch reactor (SBR). The system achieved 55 ± 5% conversion of the 1g NH(4)(+)-N/L contained in a synthetic anaerobic digester liquor to nitrite. The N(2)O emission factor was 1.0 ± 0.1% of the ammonium converted. pH was shown to have a major impact on the N(2)O production rate of the AOB enriched culture. In the investigated pH range of 6.0-8.5, the specific N(2)O production was the lowest between pH 6.0 and 7.0 at a rate of 0.15 ± 0.01 mg N(2)O-N/h/g VSS, but increased with pH to a maximum of 0.53 ± 0.04 mg N(2)O-N/h/g VSS at pH 8.0. The same trend was also observed for the specific ammonium oxidation rate (AOR) with the maximum AOR reached at pH 8.0. A linear relationship between the N(2)O production rate and AOR was observed suggesting that increased ammonium oxidation activity may have promoted N(2)O production. The N(2)O production rate was constant across free ammonia (FA) and free nitrous acid (FNA) concentrations of 5-78 mg NH(3)-N/L and 0.15-4.6 mg HNO(2)-N/L, respectively, indicating that the observed pH effect was not due to changes in FA or FNA concentrations. Copyright © 2011 Elsevier Ltd. All rights reserved.

Municipal wastewater biological nutrient removal driven by the fermentation liquid of dairy wastewater.

PubMed

Liu, Hui; Chen, Yinguang; Wu, Jiang

2017-11-01

Carbon substrate is required by biological nutrient removal (BNR) microorganism, but it is usually insufficient in the influent of many municipal wastewater treatment plants. In this study the use of ethanol-enriched fermentation liquid, which was derived from dairy wastewater, as the preferred carbon substrate of BNR was reported. First, the application of dairy wastewater and food processing wastewater and their fermentation liquid as the carbon substrate of BNR was compared in the short-term tests. The fermented wastewater showed higher BNR performance than the unfermented one, and the fermentation liquid of dairy wastewater (FL-DW), which was obtained under pH 8 and fermentation time of 6 day, exhibited the highest phosphorus (95.5%) and total nitrogen (97.6%) removal efficiencies due to its high ethanol content (57.9%). Then, the long-term performance of FL-DW acting as the carbon substrate of BNR was compared with that of acetate and ethanol, and the FL-DW showed the greatest phosphorus and total nitrogen removal. Further investigation showed that the use of FL-DW caused the highest polyhydroxyalkanoates (PHAs) synthesis in BNR microbial cells, and more PHAs were used for phosphorus uptake and denitrification rather than glycogen synthesis and microbial growth. The FL-DW can be used as a preferred carbon substrate for BNR microbes. AB: aerobic end sludge active biomass; BNR: biological nutrient removal; DW: dairy wastewater; FL-DW: fermentation liquid of dairy wastewater; FPW: food processing wastewater; FL-FPW: fermentation liquid of food processing wastewater; PHAs: polyhydroxyalkanoates; PHB: poly-3-hydroxybutyrate; PHV: poly-3-hydroxyvalerate; PH2MV: poly-3-hydroxy-2- methylvalerate; PAOs: phosphorus accumulating organisms; SBR: sequencing batch reactor; SOP: soluble ortho-phosphorus; TN: total nitrogen; TSS: total suspended solids; VSS: volatile suspended solids; VFAs: volatile fatty acids; WWTPs: wastewater treatment plants.

Seasonal variation and removal efficiency of antibiotic resistance genes during wastewater treatment of swine farms.

PubMed

Sui, Qianwen; Zhang, Junya; Tong, Juan; Chen, Meixue; Wei, Yuansong

2017-04-01

The seasonal variation and removal efficiency of antibiotic resistance genes (ARGs), including tetracycline resistance genes (tetG, tetM, and tetX) and macrolide (ermB, ermF, ereA, and mefA), were investigated in two typical swine wastewater treatment systems in both winter and summer. ARGs, class 1 integron gene, and 16S rRNA gene were quantified using real-time polymerase chain reaction assays. There was a 0.31-3.52 log variation in ARGs in raw swine wastewater, and the abundance of ARGs in winter was higher than in summer. tetM, tetX, ermB, ermF, and mefA were highly abundant. The abundance of ARGs was effectively reduced by most individual treatment process and the removal efficiencies of ARGs were higher in winter than in summer. However, when examining relative abundance, the fate of ARGs was quite variable. Anaerobic digestion reduced the relative abundance of tetX, ermB, ermF, and mefA, while lagoon treatment decreased tetM, ermB, ermF, and mefA. Sequencing batch reactor (SBR) decreased tetM, ermB, and ermF, but biofilters and wetlands did not display consistent removal efficiency on ARGs in two sampling seasons. As far as the entire treatment system is concerned, ermB and mefA were effectively reduced in both winter and summer in both total and relative abundance. The relative abundances of tetG and ereA were significantly correlated with intI1 (p < 0.01), and both tetG and ereA increased after wastewater treatment. This may pose a great threat to public health.

Enhanced interfacial interaction and antioxidative behavior of novel halloysite nanotubes/silica hybrid supported antioxidant in styrene-butadiene rubber

NASA Astrophysics Data System (ADS)

Lin, Jing; Luo, Yuanfang; Zhong, Bangchao; Hu, Dechao; Jia, Zhixin; Jia, Demin

2018-05-01

A novel antioxidant (HS-s-RT) to improve the mechanical properties and anti-aging performance of styrene-butadiene (SBR) composites was prepared by antioxidant intermediate p-aminodiphenylamine (RT) grafting on the surface of halloysite nanotubes/silica hybrid (HS) via the linkage of silane coupling agent. The analysis of SEM and rubber processing analyzer (RPA) demonstrated HS-s-RT was uniformly dispersed in SBR, and stronger interfacial interaction between HS-s-RT and SBR was formed. Consequently, SBR/HS-s-RT composites have improving mechanical properties. Furthermore, the test of the retention of mechanical properties, Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), and oxidation induction time (OIT) showed HS-s-RT can effectively improve the anti-aging effect of SBR composites than corresponding low molecular-weight antioxidant N-isopropyl-N‧-phenyl-4-phenylenediamin (4010NA). Then, the mechanism of thermo-oxidative aging of SBR/HS composites was also investigated, and the superior antioxidative efficiency is attributed to the uniform dispersion and excellent migration resistance of HS-s-RT. Hence, this novel antioxidant might open up new opportunities for the fabrication of high-performance rubber composites due to its superior anti-aging effect and reinforcement.

Deactivation of TEM-1 β-Lactamase Investigated by Isothermal Batch and Non-Isothermal Continuous Enzyme Membrane Reactor Methods

PubMed Central

Rogers, Thomas A.

2011-01-01

The thermal deactivation of TEM-1 β-lactamase was examined using two experimental techniques: a series of isothermal batch assays and a single, continuous, non-isothermal assay in an enzyme membrane reactor (EMR). The isothermal batch-mode technique was coupled with the three-state “Equilibrium Model” of enzyme deactivation, while the results of the EMR experiment were fitted to a four-state “molten globule model”. The two methods both led to the conclusions that the thermal deactivation of TEM-1 β-lactamase does not follow the Lumry-Eyring model and that the Teq of the enzyme (the point at which active and inactive states are present in equal amounts due to thermodynamic equilibrium) is at least 10 °C from the Tm (melting temperature), contrary to the idea that the true temperature optimum of a biocatalyst is necessarily close to the melting temperature. PMID:22039393

Complete Non-Radioactive Operability Tests for Cladding Hull Chlorination

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

Collins, Emory D; Johnson, Jared A.; Hylton, Tom D.

2016-04-01

Non-radioactive operability tests were made to test the metal chlorination reactor and condenser and their accessories using batch chlorinations of non-radioactive cladding samples and to identify optimum operating practices and components that need further modifications prior to installation of the equipment into the hot cell for tests on actual used nuclear fuel (UNF) cladding. The operability tests included (1) modifications to provide the desired heating and reactor temperature profile; and (2) three batch chlorination tests using, respectively, 100, 250, and 500 g of cladding. During the batch chlorinations, metal corrosion of the equipment was assessed, pressurization of the gas inletmore » was examined and the best method for maintaining solid salt product transfer through the condenser was determined. Also, additional accessing equipment for collection of residual ash and positioning of the unit within the hot cell were identified, designed, and are being fabricated.« less

Pre-treatment processes of Azolla filiculoides to remove Pb(II), Cd(II), Ni(II) and Zn(II) from aqueous solution in the batch and fixed-bed reactors.

PubMed

Khosravi, Morteza; Rakhshaee, Roohan; Ganji, Masuod Taghi

2005-12-09

Intact and treated biomass can remove heavy metals from water and wastewater. This study examined the ability of the activated, semi-intact and inactivated Azolla filiculoides (a small water fern) to remove Pb(2+), Cd(2+), Ni(2+) and Zn(2+) from the aqueous solution. The maximum uptake capacities of these metal ions using the activated Azolla filiculoides by NaOH at pH 10.5 +/- 0.2 and then CaCl(2)/MgCl(2)/NaCl with total concentration of 2 M (2:1:1 mole ratio) in the separate batch reactors were obtained about 271, 111, 71 and 60 mg/g (dry Azolla), respectively. The obtained capacities of maximum adsorption for these kinds of the pre-treated Azolla in the fixed-bed reactors (N(o)) were also very close to the values obtained for the batch reactors (Q(max)). On the other hand, it was shown that HCl, CH(3)OH, C(2)H(5)OH, FeCl(2), SrCl(2), BaCl(2) and AlCl(3) in the pre-treatment processes decreased the ability of Azolla to remove the heavy metals in comparison to the semi-intact Azolla, considerably. The kinetic studies showed that the heavy metals uptake by the activated Azolla was done more rapid than those for the semi-intact Azolla.

SiC layer microstructure in AGR-1 and AGR-2 TRISO fuel particles and the influence of its variation on the effective diffusion of key fission products

DOE PAGES

Gerczak, Tyler J.; Hunn, John D.; Lowden, Richard A.; ...

2016-08-15

Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy’s Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representativemore » of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Finally, insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.« less

CALIBRATION OF FULL-SCALE OZONATION SYSTEMS WITH CONSERVATIVE AND REACTIVE TRACERS

EPA Science Inventory

A full-scale ozonation reactor was characterized with respect to the overall oxidation budget by coupling laboratory kinetics with reactor hydraulics. The ozone decomposition kinetics and the ratio of the OH radical to the ozone concentration were determined in laboratory batch ...

Impact of thermal spectrum small modular reactors on performance of once-through nuclear fuel cycles with low-enriched uranium

DOE PAGES

Brown, Nicholas R.; Worrall, Andrew; Todosow, Michael

2016-11-18

Small modular reactors (SMRs) offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of SMRs on nuclear fuel cycle performance. The focus of this paper is the fuel cycle impacts of light water SMRs in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary example reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Options Campaign. The hypothetical light water SMR example case considered in these preliminary scoping studies ismore » a cartridge type one-batch core with slightly less than 5.0% enrichment. Challenges associated with SMRs include increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burnup in the reactor and the fuel cycle performance. This paper summarizes a list of the factors relevant to SMR fuel, core, and operation that will impact fuel cycle performance. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burnup of the reactor. Fuel cycle performance metrics for a hypothetical example SMR are compared with those for a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. The metrics performance for such an SMR is degraded for the mass of spent nuclear fuel and high-level waste disposed of, mass of depleted uranium disposed of, land use per energy generated, and carbon emissions per energy generated. Finally, it is noted that the features of some SMR designs impact three main aspects of fuel cycle performance: (1) small cores which means high leakage (there is a radial and axial component), (2) no boron which means heterogeneous core and extensive use of control rods and BPs, and (3) single batch cores. But not all of the SMR designs have all of these traits. As a result, the approach used in this study is therefore a bounding case and not all SMRs may be affected to the same extent.« less

Measuring the reactivity of commercially available zero-valent iron nanoparticles used for environmental remediation with iopromide.

PubMed

Schmid, Doris; Micić, Vesna; Laumann, Susanne; Hofmann, Thilo

2015-10-01

The high specific surface area and high reactivity of nanoscale zero-valent iron (nZVI) particles have led to much research on their application to environmental remediation. The reactivity of nZVI is affected by both the water chemistry and the properties of the particular type of nZVI particle used. We have investigated the reactivity of three types of commercially available Nanofer particles (from Nanoiron, s.r.o., Czech Republic) that are currently either used in, or proposed for use in full scale environmental remediation projects. The performance of one of these, the air-stable and thus easy-to-handle Nanofer Star particle, has not previously been reported. Experiments were carried out first in batch shaking reactors in order to derive maximum reactivity rates and provide a rapid estimate of the Nanofer particle's reactivity. The experiments were performed under near-natural environmental conditions with respect to the pH value of water and solute concentrations, and results were compared with those obtained using synthetic water. Thereafter, the polyelectrolyte-coated Nanofer 25S particles (having the highest potential for transport within porous media) were chosen for the experiments in column reactors, in order to elucidate nanoparticle reactivity under a more field-site realistic setting. Iopromide was rapidly dehalogenated by the investigated nZVI particles, following pseudo-first-order reaction kinetics that was independent of the experimental conditions. The specific surface area normalized reaction rate constant (kSA) value in the batch reactors ranged between 0.12 and 0.53Lm(-2)h(-1); it was highest for the uncoated Nanofer 25 particles, followed by the polyacrylic acid-coated Nanofer 25S and air-stable Nanofer Star particles. In the batch reactors all particles were less reactive in natural water than in synthetic water. The kSA values derived from the column reactor experiments were about 1000 times lower than those from the batch reactors, ranging between 2.6×10(-4) and 5.7×10(-4)Lm(-2)h(-1). Our results revealed that the easy-to-handle and air-stable Nanofer Star particles are the least reactive of all the Nanofer products tested. The reaction kinetics predicted by column experiments were more realistic than those predicted by batch experiments and these should therefore be used when designing a full-scale field application of nanomaterials for environmental remediation. Copyright © 2015 Elsevier B.V. All rights reserved.

Minimizing mixing intensity to improve the performance of rice straw anaerobic digestion via enhanced development of microbe-substrate aggregates.

PubMed

Kim, Moonkyung; Kim, Byung-Chul; Choi, Yongju; Nam, Kyoungphile

2017-12-01

The aim of this work was to study the effect of the differential development of microbe-substrate aggregates at different mixing intensities on the performance of anaerobic digestion of rice straw. Batch and semi-continuous reactors were operated for up to 50 and 300days, respectively, under different mixing intensities. In both batch and semi-continuous reactors, minimal mixing conditions exhibited maximum methane production and lignocellulose biodegradability, which both had strong correlations with the development of microbe-substrate aggregates. The results implied that the aggregated microorganisms on the particulate substrate played a key role in rice straw hydrolysis, determining the performance of anaerobic digestion. Increasing the mixing speed from 50 to 150rpm significantly reduced the methane production rate by disintegrating the microbe-substrate aggregates in the semi-continuous reactor. A temporary stress of high-speed mixing fundamentally affected the microbial communities, increasing the possibility of chronic reactor failure. Copyright © 2017 Elsevier Ltd. All rights reserved.

12 weeks of simulated barefoot running changes foot-strike patterns in female runners.

PubMed

McCarthy, C; Fleming, N; Donne, B; Blanksby, B

2014-05-01

To investigate the effect of a transition program of simulated barefoot running (SBR) on running kinematics and foot-strike patterns, female recreational athletes (n=9, age 29 ± 3 yrs) without SBR experience gradually increased running distance in Vibram FiveFingers SBR footwear over 12 weeks. Matched controls (n=10, age 30 ± 4 yrs) continued running in standard footwear. A 3-D motion analysis of treadmill running at 12 km/h(-1) was performed by both groups, barefoot and shod, pre- and post-intervention. Post-intervention data indicated a more-forefoot strike pattern in the SBR group compared to controls; both running barefoot (P>0.05), and shod (P<0.001). When assessed barefoot, there were significant kinematic differences across time in the SBR group for ankle flexion angle at toe-off (P<0.01). When assessed shod, significant kinematic changes occurred across time, for ankle flexion angles at foot-strike (P<0.001) and toe-off (P<0.01), and for range of motion (ROM) in the absorptive phase of stance (P<0.01). A knee effect was recorded in the SBR group for flexion ROM in the absorptive phase of stance (P<0.05). No significant changes occurred in controls. Therefore, a 12-week transition program in SBR could assist athletes seeking a more-forefoot strike pattern and "barefoot" kinematics, regardless of preferred footwear. © Georg Thieme Verlag KG Stuttgart · New York.

Continuous Production of Ethanol from Starch Using Glucoamylase and Yeast Co-Immobilized in Pectin Gel

NASA Astrophysics Data System (ADS)

Giordano, Raquel L. C.; Trovati, Joubert; Schmidell, Willibaldo

This work presents a continuous simultaneous saccharification and fermentation (SSF) process to produce ethanol from starch using glucoamylase and Saccharomyces cerevisiae co-immobilized in pectin gel. The enzyme was immobilized on macroporous silica, after silanization and activation of the support with glutaraldehyde. The silicaenzyme derivative was co-immobilized with yeast in pectin gel. This biocatalyst was used to produce ethanol from liquefied manioc root flour syrup, in three fixed bed reactors. The initial reactor yeast load was 0.05 g wet yeast/ml of reactor (0.1 g wet yeast/g gel), used in all SSF experiments. The enzyme concentration in the reactor was defined by running SSF batch assays, using different amount of silica-enzyme derivative, co-immobilized with yeast in pectin gel. The chosen reactor enzyme concentration, 3.77 U/ml, allowed fermentation to be the rate-limiting step in the batch experiment. In this condition, using initial substrate concentration of 166.0 g/1 of total reducing sugars (TRS), 1 ml gel/1 ml of medium, ethanol productivity of 8.3 g/l/h was achieved, for total conversion of starch to ethanol and 91% of the theoretical yield. In the continuous runs, feeding 163.0 g/1 of TRS and using the same enzyme and yeast concentrations used in the batch run, ethanol productivity was 5.9 g ethanol/1/h, with 97% of substrate conversion and 81% of the ethanol theoretical yield. Diffusion effects in the extra-biocatalyst film seemed to be reduced when operating at superficial velocities above 3.7 × 10-4 cm/s.

Continuous production of ethanol from starch using glucoamylase and yeast co-immobilized in pectin gel.

PubMed

Giordano, Raquel L C; Trovati, Joubert; Schmidell, Willibaldo

2008-03-01

This work presents a continuous simultaneous saccharification and fermentation (SSF) process to produce ethanol from starch using glucoamylase and Saccharomyces cerevisiae co-immobilized in pectin gel. The enzyme was immobilized on macroporous silica, after silanization and activation of the support with glutaraldehyde. The silica-enzyme derivative was co-immobilized with yeast in pectin gel. This biocatalyst was used to produce ethanol from liquefied manioc root flour syrup, in three fixed bed reactors. The initial reactor yeast load was 0.05 g wet yeast/ml of reactor (0.1 g wet yeast/g gel), used in all SSF experiments. The enzyme concentration in the reactor was defined by running SSF batch assays, using different amount of silica-enzyme derivative, co-immobilized with yeast in pectin gel. The chosen reactor enzyme concentration, 3.77 U/ml, allowed fermentation to be the rate-limiting step in the batch experiment. In this condition, using initial substrate concentration of 166.0 g/l of total reducing sugars (TRS), 1 ml gel/1 ml of medium, ethanol productivity of 8.3 g/l/h was achieved, for total conversion of starch to ethanol and 91% of the theoretical yield. In the continuous runs, feeding 163.0 g/l of TRS and using the same enzyme and yeast concentrations used in the batch run, ethanol productivity was 5.9 g ethanol/l/h, with 97% of substrate conversion and 81% of the ethanol theoretical yield. Diffusion effects in the extra-biocatalyst film seemed to be reduced when operating at superficial velocities above 3.7 x 10(-4) cm/s.

Evaluation of Heat Recuperation in a Concentric Hydrogen Reduction Reactor

NASA Technical Reports Server (NTRS)

Linne, Diane; Kleinhenz, Julie; Hegde, Uday

2012-01-01

Heat recuperation in an ISRU reactor system involves the recovery of heat from a reacted regolith batch by transferring this energy into a batch of fresh regolith. One concept for a hydrogen reduction reactor is a concentric chamber design where heat is transferred from the inner, reaction chamber into fresh regolith in the outer, recuperation chamber. This concept was tested and analyzed to define the overall benefit compared to a more traditional single chamber batch reactor. Data was gathered for heat-up and recuperation in the inner chamber alone, simulating a single chamber design, as well as recuperation into the outer chamber, simulating a dual chamber design. Experimental data was also used to improve two analytical models, with good agreement for temperature behavior during recuperation, calculated mass of the reactor concepts, and energy required during heat-up. The five tests, performed using JSC-1A regolith simulant, also explored the effectiveness of helium gas fluidization, hydrogen gas fluidization, and vibrational fluidization. Results indicate that higher hydrogen volumetric flow rates are required compared to helium for complete fluidization and mixing, and that vibrational fluidization may provide equivalent mixing while eliminating the need to flow large amounts of excess hydrogen. Analysis of the total energy required for heat-up and steady-state operations for a variety of conditions and assumptions shows that the dual-chamber concept requires the same or more energy than the single chamber concept. With no clear energy savings, the added mass and complexity of the dual-chamber makes it unlikely that this design concept will provide any added benefit to the overall ISRU oxygen production system.

Improving the throughput of batch photochemical reactions using flow: Dual photoredox and nickel catalysis in flow for C(sp2)C(sp3) cross-coupling.

PubMed

Abdiaj, Irini; Alcázar, Jesús

2017-12-01

We report herein the transfer of dual photoredox and nickel catalysis for C(sp 2 )C(sp 3 ) cross coupling form batch to flow. This new procedure clearly improves the scalability of the previous batch reaction by the reactor's size and operating time reduction, and allows the preparation of interesting compounds for drug discovery in multigram amounts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reinforcement of SBR/waste rubber powder vulcanizate with in situ generated zinc dimethacrylate

NASA Astrophysics Data System (ADS)

Wang, X. P.; Cheng, B. K.; Zhang, X.; Jia, D. M.

2016-07-01

Methyl acrylic acid/zinc oxide (MAA/ZnO) was introduced to modify styrene- butadiene rubber/waste rubber powder (SBR/WRP) composites by blending. The enhanced mechanical properties and processing ability were presumably originated from improved compatibility and interfacial interaction between WRP and the SBR matrix by the in situ polymerization of zinc dimethacrylate (ZDMA). A refined interface of the modified SBR/WRP composite was observed by scanning electron microscopy. The formation of ZDMA significantly increased the ionic bond content in the vulcanizate, resulting in exceptional mechanical performance. The comprehensive mechanical properties including tensile strength, tear strength and dynamic heat-building performance reached optimum values with 16 phr MAA.

Complete genome sequence of Paenibacillus riograndensis SBR5(T), a Gram-positive diazotrophic rhizobacterium.

PubMed

Brito, Luciana Fernandes; Bach, Evelise; Kalinowski, Jörn; Rückert, Christian; Wibberg, Daniel; Passaglia, Luciane M; Wendisch, Volker F

2015-08-10

Paenibacillus riograndensis is a Gram-positive rhizobacterium which exhibits plant growth promoting activities. It was isolated from the rhizosphere of wheat grown in the state of Rio Grande do Sul, Brazil. Here we announce the complete genome sequence of P. riograndensis strain SBR5(T). The genome of P. riograndensis SBR5(T) consists of a circular chromosome of 7,893,056bps. The genome was finished and fully annotated, containing 6705 protein coding genes, 87 tRNAs and 27 rRNAs. The knowledge of the complete genome helped to explain why P. riograndensis SBR5(T) can grow with the carbon sources arabinose and mannitol, but not myo-inositol, and to explain physiological features such as biotin auxotrophy and antibiotic resistances. The genome sequence will be valuable for functional genomics and ecological studies as well as for application of P. riograndensis SBR5(T) as plant growth-promoting rhizobacterium. Copyright © 2015 Elsevier B.V. All rights reserved.

TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

EPA Science Inventory

The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

ANALYSIS OF AN AEROBIC FLUIDIZED BED REACTOR DEGRADING MTBE AND BTEX AT REDUCED EBCTS

EPA Science Inventory

The purpose of this study was to investigate the biodegradation of MTBE and BTEX using a fluidized bed reactor (FBR) with granular activated carbon (GAC) as a biological attachment medium. Batch experiments were run to analyze the MTBE and TBA degradation kinetics of the culture ...

Fracto-Emission from Polymers.

DTIC Science & Technology

1983-06-01

Table II Material Avg. Total EE 1/M c SBR-1 23000 0.00024 SBR-1 (UV-irradiated) 27000 0.00029 SBR-1 ( -irradiated) 38000 0.00110 BR-2 35000 0.00100...85- 500 Sooo I t 0 50 100 ISO 200 250 TIME (sec) -86- 11,00" z= 0 50 100 150 200 250 TIME (sec) Sa. 1,K -87- 700 AA a .~I~J.J- -88- 4000 0 o10IO200

Bioprocessing Data for the Production of Marine Enzymes

PubMed Central

Sarkar, Sreyashi; Pramanik, Arnab; Mitra, Anindita; Mukherjee, Joydeep

2010-01-01

This review is a synopsis of different bioprocess engineering approaches adopted for the production of marine enzymes. Three major modes of operation: batch, fed-batch and continuous have been used for production of enzymes (such as protease, chitinase, agarase, peroxidase) mainly from marine bacteria and fungi on a laboratory bioreactor and pilot plant scales. Submerged, immobilized and solid-state processes in batch mode were widely employed. The fed-batch process was also applied in several bioprocesses. Continuous processes with suspended cells as well as with immobilized cells have been used. Investigations in shake flasks were conducted with the prospect of large-scale processing in reactors. PMID:20479981

Novel duplex vapor: Electrochemical method for silicon solar cells. [chemical reactor for a silicon sodium reaction system

NASA Technical Reports Server (NTRS)

Nanis, L.; Sanjurjo, A.; Sancier, K.

1979-01-01

The scaled up chemical reactor for a SiF4-Na reaction system is examined for increased reaction rate and production rate. The reaction system which now produces 5 kg batches of mixed Si and NaF is evaluated. The reactor design is described along with an analysis of the increased capacity of the Na chip feeder. The reactor procedure is discussed and Si coalescence in the reaction products is diagnosed.

Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites.

PubMed

Noda, Yohei; Koizumi, Satoshi; Masui, Tomomi; Mashita, Ryo; Kishimoto, Hiroyuki; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shin-Ichi; Ohishi, Kazuki; Suzuki, Jun-Ichi

2016-12-01

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization ( P H ). The following samples were prepared: (i) a binary mixture of styrene-butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping its q dependence for P H = -35% or P H = 40%, respectively. The q behaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at low q (∼0.01 Å -1 ) varied as a quadratic function of P H and indicated a minimum value at P H = 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at high q (∼0.3 Å -1 ) decreased with increasing P H , which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), the q behaviour of SANS was varied by changing P H . At P H = -35%, the scattering maxima originating from the form factor of SP prevailed, whereas at P H = 29% and P H = 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according to q -3.6 , which is consistent with the results for the SBR/CP mixture.

Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites1

PubMed Central

Noda, Yohei; Koizumi, Satoshi; Masui, Tomomi; Mashita, Ryo; Kishimoto, Hiroyuki; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shin-ichi; Ohishi, Kazuki; Suzuki, Jun-ichi

2016-01-01

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization (P H). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping its q dependence for P H = −35% or P H = 40%, respectively. The q behaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at low q (∼0.01 Å−1) varied as a quadratic function of P H and indicated a minimum value at P H = 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at high q (∼0.3 Å−1) decreased with increasing P H, which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), the q behaviour of SANS was varied by changing P H. At P H = −35%, the scattering maxima originating from the form factor of SP prevailed, whereas at P H = 29% and P H = 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according to q −3.6, which is consistent with the results for the SBR/CP mixture. PMID:27980510

Coal desulfurization by low temperature chlorinolysis, phase 3

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Rohatgi, N. K.; Ernest, J.

1981-01-01

Laboratory scale, bench scale batch reactor, and minipilot plant tests were conducted on 22 bituminous, subbituminous, and lignite coals. Chemical pretreatment and post treatment of coals relative to the chlorination were tried as a means of enhancing desulfurization by the chlorinolysis process. Elevated temperature (500-700 C) hydrogen treatment of chlorinolysis-processed coal at atmospheric pressure was found to substantially increase coal desulfurization up to 90 percent. Sulfur forms, proximate and ultimate analyses of the processed coal are included. Minipilot plant operation indicates that the continuous flow reactor provides coal desulfurization results comparable to those obtained in the batch reactor. Seven runs were conducted at coal feed rates of 1.5 to 8.8 kg per hour using water and methylchloroform solvents, gaseous chlorine feed of 3 to 31.4 SCFH at 21 to 70 C, and atmospheric pressure for retention times of 20 to 120 minutes.

Flow photochemistry: Old light through new windows

PubMed Central

Knowles, Jonathan P; Elliott, Luke D

2012-01-01

Summary Synthetic photochemistry carried out in classic batch reactors has, for over half a century, proved to be a powerful but under-utilised technique in general organic synthesis. Recent developments in flow photochemistry have the potential to allow this technique to be applied in a more mainstream setting. This review highlights the use of flow reactors in organic photochemistry, allowing a comparison of the various reactor types to be made. PMID:23209538

Characterization of efficient aerobic denitrifiers isolated from two different sequencing batch reactors by 16S-rRNA analysis.

PubMed

Wang, Ping; Li, Xiuting; Xiang, Mufei; Zhai, Qian

2007-06-01

By adopting two sequencing batch reactors (SBRs) A and B, nitrate as the substrate, and the intermittent aeration mode, activated sludge was domesticated to enrich aerobic denitrifiers. The pHs of reactor A were approximately 6.3 at DOs 2.2-6.1 mg/l for a carbon source of 720 mg/l COD; the pHs of reactor B were 6.8-7.8 at DOs 2.2-3.0 mg/l for a carbon source of 1500 mg/l COD. Both reactors maintained an influent nitrate concentration of 80 mg/l NO3- -N. When the total inorganic nitrogen (TIN) removal efficiency of both reactors reached 60%, aerobic denitrifier accumulation was regarded completed. By bromthymol blue (BTB) medium, 20 bacteria were isolated from the two SBRs and DNA samples of 8 of these 20 strains were amplified by PCR and processed for 16SrRNA sequencing. The obtained results were analysed by a Blast similarity search of the GenBank database, and constructing a phylogenetic tree for identification by comparison. The 8 bacteria were found to belong to the genera Pseudomonas, Delftia, Herbaspirillum and Comamonas. At present, no Delftia has been reported to be an aerobic denitrifier.

Control of algal production in a high rate algal pond: investigation through batch and continuous experiments.

PubMed

Derabe Maobe, H; Onodera, M; Takahashi, M; Satoh, H; Fukazawa, T

2014-01-01

For decades, arid and semi-arid regions in Africa have faced issues related to water availability for drinking, irrigation and livestock purposes. To tackle these issues, a laboratory scale greywater treatment system based on high rate algal pond (HRAP) technology was investigated in order to guide the operation of the pilot plant implemented in the 2iE campus in Ouagadougou (Burkina Faso). Because of the high suspended solids concentration generally found in effluents of this system, the aim of this study is to improve the performance of HRAPs in term of algal productivity and removal. To determine the selection mechanism of self-flocculated algae, three sets of sequencing batch reactors (SBRs) and three sets of continuous flow reactors (CFRs) were operated. Despite operation with the same solids retention time and the similarity of the algal growth rate found in these reactors, the algal productivity was higher in the SBRs owing to the short hydraulic retention time of 10 days in these reactors. By using a volume of CFR with twice the volume of our experimental CFRs, the algal concentration can be controlled during operation under similar physical conditions in both reactors.

Acceptance Test Data for the AGR-5/6/7 Irradiation Test Fuel Composite Defective IPyC Fraction and Pyrocarbon Anisotropy

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

Helmreich, Grant W.; Hunn, John D.; Skitt, Darren J.

Coated particle composite J52R-16-98005 was produced by Babcock and Wilcox Technologies (BWXT) as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR). This composite was comprised of four coated particle fuel batches J52O-16-93165B (26%), 93168B (26%), 93169B (24%), and 93170B (24%), chosen based on the Quality Control (QC) data acquired for each individual candidate AGR-5/6/7 batch. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT Lot J52R-16-69317more » containing a mixture of 15.5%-enriched uranium carbide and uranium oxide (UCO). The TRISO coatings consisted of four consecutive CVD layers: a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. The TRISO-coated particle batches were sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batches were designated by appending the letter A to the end of the batch number (e.g., 93165A). Secondary upgrading by sieving was performed on the A-designated batches to remove particles with missing or very-thin buffer layers that were identified during previous analysis of the individual batches for defective IPyC, as reported in the acceptance test data report for the AGR-5/6/7 production batches [Hunn et al. 2017]. The additionally-upgraded batches were designated by appending the letter B to the end of the batch number (e.g., 93165B).« less

An experimental study of ammonia borane based hydrogen storage systems

NASA Astrophysics Data System (ADS)

Deshpande, Kedaresh A.

2011-12-01

Hydrogen is a promising fuel for the future, capable of meeting the demands of energy storage and low pollutant emission. Chemical hydrides are potential candidates for chemical hydrogen storage, especially for automobile applications. Ammonia borane (AB) is a chemical hydride being investigated widely for its potential to realize the hydrogen economy. In this work, the yield of hydrogen obtained during neat AB thermolysis was quantified using two reactor systems. First, an oil bath heated glass reactor system was used with AB batches of 0.13 gram (+/- 0.001 gram). The rates of hydrogen generation were measured. Based on these experimental data, an electrically heated steel reactor system was designed and constructed to handle up to 2 grams of AB per batch. A majority of components were made of stainless-steel. The system consisted of an AB reservoir and feeder, a heated reactor, a gas processing unit and a system control and monitoring unit. An electronic data acquisition system was used to record experimental data. The performance of the steel reactor system was evaluated experimentally through batch reactions of 30 minutes each, for reaction temperatures in the range from 373 K to 430 K. The experimental data showed exothermic decomposition of AB accompanied by rapid generation of hydrogen during the initial period of the reaction. 90% of the hydrogen was generated during the initial 120 seconds after addition of AB to the reactor. At 430 K, the reaction produced 12 wt.% of hydrogen. The heat diffusion in the reactor system and the process of exothermic decomposition of AB were coupled in a two-dimensional model. Neat AB thermolysis was modeled as a global first order reactions based on Arrhenius theory. The values of equation constants were derived from curve fit of experimental data. The pre-exponential constant and the activation energy were estimated to be 4 s-1 (+/- 0.4 s-1) and 13000 J mol -1 s-1 (+/- 1050 J mol-1 s -1) respectively. The model was solved in COMSOL Multiphysics. The model was capable of simulating the transient response of the system and captured the observed trends such as the decrease in reactor temperature upon addition of AB and exothermic decomposition.

Bagasse hydrolyzates from Agave tequilana as substrates for succinic acid production by Actinobacillus succinogenes in batch and repeated batch reactor.

PubMed

Corona-González, Rosa Isela; Varela-Almanza, Karla María; Arriola-Guevara, Enrique; Martínez-Gómez, Álvaro de Jesús; Pelayo-Ortiz, Carlos; Toriz, Guillermo

2016-04-01

The aim of this work was to obtain fermentable sugars by enzymatic or acid hydrolyses of Agave tequilana Weber bagasse in order to produce succinic acid with Actinobacillus succinogenes. Hydrolyses were carried out with mineral acids (sulfuric and hydrochloric acids) or a commercial cellulolytic enzyme, and were optimized statistically by a response surface methodology, having as factors the concentration of acid/enzyme and time of hydrolysis. The concentration of sugars obtained at optimal conditions for each hydrolysis were 21.7, 22.4y 19.8g/L for H2SO4, HCl and the enzymatic preparation respectively. Concerning succinic acid production, the enzymatic hydrolyzates resulted in the highest yield (0.446g/g) and productivity (0.57g/Lh) using A. succinogenes in a batch reactor system. Repeated batch fermentation with immobilized A. succinogenes in agar and with the enzymatic hydrolyzates resulted in a maximum concentration of succinic acid of 33.6g/L from 87.2g/L monosaccharides after 5 cycles in 40h, obtaining a productivity of 1.32g/Lh. Copyright © 2016. Published by Elsevier Ltd.

Parameterized data-driven fuzzy model based optimal control of a semi-batch reactor.

PubMed

Kamesh, Reddi; Rani, K Yamuna

2016-09-01

A parameterized data-driven fuzzy (PDDF) model structure is proposed for semi-batch processes, and its application for optimal control is illustrated. The orthonormally parameterized input trajectories, initial states and process parameters are the inputs to the model, which predicts the output trajectories in terms of Fourier coefficients. Fuzzy rules are formulated based on the signs of a linear data-driven model, while the defuzzification step incorporates a linear regression model to shift the domain from input to output domain. The fuzzy model is employed to formulate an optimal control problem for single rate as well as multi-rate systems. Simulation study on a multivariable semi-batch reactor system reveals that the proposed PDDF modeling approach is capable of capturing the nonlinear and time-varying behavior inherent in the semi-batch system fairly accurately, and the results of operating trajectory optimization using the proposed model are found to be comparable to the results obtained using the exact first principles model, and are also found to be comparable to or better than parameterized data-driven artificial neural network model based optimization results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Microbial ureolysis in the seawater-catalysed urine phosphorus recovery system: Kinetic study and reactor verification.

PubMed

Tang, Wen-Tao; Dai, Ji; Liu, Rulong; Chen, Guang-Hao

2015-12-15

Our previous study has confirmed the feasibility of using seawater as an economical precipitant for urine phosphorus (P) precipitation. However, we still understand very little about the ureolysis in the Seawater-based Urine Phosphorus Recovery (SUPR) system despite its being a crucial step for urine P recovery. In this study, batch experiments were conducted to investigate the kinetics of microbial ureolysis in the seawater-urine system. Indigenous bacteria from urine and seawater exhibited relatively low ureolytic activity, but they adapted quickly to the urine-seawater mixture during batch cultivation. During cultivation, both the abundance and specific ureolysis rate of the indigenous bacteria were greatly enhanced as confirmed by a biomass-dependent Michaelis-Menten model. The period for fully ureolysis was decreased from 180 h to 2.5 h after four cycles of cultivation. Based on the successful cultivation, a lab-scale SUPR reactor was set up to verify the fast ureolysis and efficient P recovery in the SUPR system. Nearly complete urine P removal was achieved in the reactor in 6 h without adding any chemicals. Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis revealed that the predominant groups of bacteria in the SUPR reactor likely originated from seawater rather than urine. Moreover, batch tests confirmed the high ureolysis rates and high phosphorus removal efficiency induced by cultivated bacteria in the SUPR reactor under seawater-to-urine mixing ratios ranging from 1:1 to 9:1. This study has proved that the enrichment of indigenous bacteria in the SUPR system can lead to sufficient ureolytic activity for phosphate precipitation, thus providing an efficient and economical method for urine P recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acceptance Test Data for BWXT Coated Particle Batch 93164A Defective IPyC Fraction and Pyrocarbon Anisotropy

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

Helmreich, Grant W.; Hunn, John D.; Skitt, Darren J.

2017-02-01

Coated particle fuel batch J52O-16-93164 was produced by Babcock and Wilcox Technologies (BWXT) for possible selection as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR), or may be used as demonstration production-scale coated particle fuel for other experiments. The tristructural-isotropic (TRISO) coatings were deposited in a 150-mm-diameter production-scale fluidizedbed chemical vapor deposition (CVD) furnace onto 425-μm-nominal-diameter spherical kernels from BWXT lot J52L-16-69316. Each kernel contained a mixture of 15.5%-enriched uranium carbide and uranium oxide (UCO) and was coated with four consecutive CVD layers:more » a ~50% dense carbon buffer layer with 100-μm-nominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. The TRISO-coated particle batch was sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batch was designated by appending the letter A to the end of the batch number (i.e., 93164A).« less

Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

ERIC Educational Resources Information Center

Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

2011-01-01

A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

Application of Lignin as Antioxidant in Styrene Butadiene Rubber Composite

NASA Astrophysics Data System (ADS)

Liu, Shusheng; Cheng, Xiansu

2010-11-01

Lignin isolated from enzymatic hydrolyzed cornstalks (EHL) is a renewable natural polymer, and rubber is one of the most important polymer materials. The application of EHL in rubber industry is of great significance. The influence of EHL and antioxidant RD on the vulcanizing characteristics, thermal oxidative aging stability under free condition, and water extraction resistance of styrene-butadiene rubber (SBR) were investigated. The effect of EHL/antioxidant D composite antioxidant on the thermal oxidative ageing of SBR was also evaluated. Results showed that the protection of SBR from thermal oxidative aging by EHL/antioxidant D composite antioxidant was superior to that of antioxidant D. This is because EHL molecules have hindered phenol group and have excellent auxiliary antioxidant role with antioxidant D. Moreover, the influence of EHL on the vulcanizing characteristics of SBR compounds was better than that of antioxidant RD, and EHL can reduce the cure rate and increase the optimum cure time. It is because that the EHL molecules have hindered phenol group and methoxy group, which can form a special structure to capture free radical and terminate the chain reaction. The retained tensile strength of SBR compounds with EHL was similar to that of the samples with antioxidant RD, while the retained elongation at break of SBR compounds with EHL was higher than that of the samples with antioxidant RD. In addition, the SBR compounds with EHL have a good water extraction resistance property, which was similar to the samples with antioxidant RD. This is because EHL have large molecular weight, good stability and low solubility in water. In conclusion, due to the low price, abundant resources, non-toxic and pollution-free, etc., EHL will have broad application prospect.

Recovery strategies for tackling the impact of phenolic compounds in a UASB reactor treating coal gasification wastewater.

PubMed

Wang, Wei; Han, Hongjun

2012-01-01

The impact of phenolic compounds (around 3.2 g/L) resulted in a completely failed performance in a mesophilic UASB reactor treating coal gasification wastewater. The recovery strategies, including extension of HRT, dilution, oxygen-limited aeration, and addition of powdered activated carbon were evaluated in batch tests, in order to obtain the most appropriate way for the quick recovery of the failed reactor performance. Results indicated that addition of powdered activated carbon and oxygen-limited aeration were the best recovery strategies in the batch tests. In the UASB reactor, addition of powdered activated carbon of 1 g/L shortened the recovery time from 25 to 9 days and oxygen-limited aeration of 0-0.5 mgO2/L reduced the recovery time to 17 days. Reduction of bioavailable concentration of phenolic compounds and recovery of sludge activity were the decisive factors for the recovery strategies to tackle the impact of phenolic compounds in anaerobic treatment of coal gasification wastewater. Copyright © 2011 Elsevier Ltd. All rights reserved.

Optimization of the moving-bed biofilm sequencing batch reactor (MBSBR) to control aeration time by kinetic computational modeling: Simulated sugar-industry wastewater treatment.

PubMed

Faridnasr, Maryam; Ghanbari, Bastam; Sassani, Ardavan

2016-05-01

A novel approach was applied for optimization of a moving-bed biofilm sequencing batch reactor (MBSBR) to treat sugar-industry wastewater (BOD5=500-2500 and COD=750-3750 mg/L) at 2-4 h of cycle time (CT). Although the experimental data showed that MBSBR reached high BOD5 and COD removal performances, it failed to achieve the standard limits at the mentioned CTs. Thus, optimization of the reactor was rendered by kinetic computational modeling and using statistical error indicator normalized root mean square error (NRMSE). The results of NRMSE revealed that Stover-Kincannon (error=6.40%) and Grau (error=6.15%) models provide better fits to the experimental data and may be used for CT optimization in the reactor. The models predicted required CTs of 4.5, 6.5, 7 and 7.5 h for effluent standardization of 500, 1000, 1500 and 2500 mg/L influent BOD5 concentrations, respectively. Similar pattern of the experimental data also confirmed these findings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Kinetic study on the effect of temperature on biogas production using a lab scale batch reactor.

PubMed

Deepanraj, B; Sivasubramanian, V; Jayaraj, S

2015-11-01

In the present study, biogas production from food waste through anaerobic digestion was carried out in a 2l laboratory-scale batch reactor operating at different temperatures with a hydraulic retention time of 30 days. The reactors were operated with a solid concentration of 7.5% of total solids and pH 7. The food wastes used in this experiment were subjected to characterization studies before and after digestion. Modified Gompertz model and Logistic model were used for kinetic study of biogas production. The kinetic parameters, biogas yield potential of the substrate (B), the maximum biogas production rate (Rb) and the duration of lag phase (λ), coefficient of determination (R(2)) and root mean square error (RMSE) were estimated in each case. The effect of temperature on biogas production was evaluated experimentally and compared with the results of kinetic study. The results demonstrated that the reactor with operating temperature of 50°C achieved maximum cumulative biogas production of 7556ml with better biodegradation efficiency. Copyright © 2015 Elsevier Inc. All rights reserved.

Successful treatment of high azo dye concentration wastewater using combined anaerobic/aerobic granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR): simultaneous adsorption and biodegradation processes.

PubMed

Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

2013-01-01

The application of a granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR) for treatment of wastewater containing 1,000 mg/L Acid Red 18 (AR18) was investigated in this research. The treatment system consisted of a sequencing batch reactor equipped with moving GAC as biofilm support. Each treatment cycle consisted of two successive anaerobic (14 h) and aerobic (8 h) reaction phases. Removal of more than 91% chemical oxygen demand (COD) and 97% AR18 was achieved in this study. Investigation of dye decolorization kinetics showed that the dye removal was stimulated by the adsorption capacity of the GAC at the beginning of the anaerobic phase and then progressed following a first-order reaction. Based on COD analysis results, at least 77.8% of the dye total metabolites were mineralized during the applied treatment system. High-performance liquid chromatography analysis revealed that more than 97% of 1-naphthyalamine-4-sulfonate as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase. According to the scanning electron microscopic analysis, the microbial biofilms grew in most cavities and pores of the GAC, but not on the external surfaces of the GAC.

(99)Tc(VII) Retardation, Reduction, and Redox Rate Scaling in Naturally Reduced Sediments.

PubMed

Liu, Yuanyuan; Liu, Chongxuan; Kukkadapu, Ravi K; McKinley, James P; Zachara, John; Plymale, Andrew E; Miller, Micah D; Varga, Tamas; Resch, Charles T

2015-11-17

An experimental and modeling study was conducted to investigate pertechnetate (Tc(VII)O4(-)) retardation, reduction, and rate scaling in three sediments from Ringold formation at U.S. Department of Energy's Hanford site, where (99)Tc is a major contaminant in groundwater. Tc(VII) was reduced in all the sediments in both batch reactors and diffusion columns, with a faster rate in a sediment containing a higher concentration of HCl-extractable Fe(II). Tc(VII) migration in the diffusion columns was reductively retarded with retardation degrees correlated with Tc(VII) reduction rates. The reduction rates were faster in the diffusion columns than those in the batch reactors, apparently influenced by the spatial distribution of redox-reactive minerals along transport paths that supplied Tc(VII). X-ray computed tomography and autoradiography were performed to identify the spatial locations of Tc(VII) reduction and transport paths in the sediments, and results generally confirmed the newly found behavior of reaction rate changes from batch to column. The results from this study implied that Tc(VII) migration can be reductively retarded at Hanford site with a retardation degree dependent on reactive Fe(II) content and its distribution in sediments. This study also demonstrated that an effective reaction rate may be faster in transport systems than that in well-mixed reactors.

Oscillations in the reduction of permanganate by hydrogen peroxide or by ninhydrin in a batch reactor and mixed-mode oscillations in a continuous-flow stirred tank reactor

NASA Astrophysics Data System (ADS)

Tóthová, Mária; Nagy, Arpád; Treindl, Ľudovít.

1999-01-01

The periodical reduction of permanganate by hydrogen peroxide or by ninhydrin with transient oscillations in a closed system has been observed and discussed in relation to the first two permanganate oscillators described earlier. The mixed-mode oscillations of the permanganate-H 2O 2 oscillating system in a continuous-flow stirred tank reactor have been described.

Effects of anti-foaming agents on biohydrogen production.

PubMed

Sivagurunathan, Periyasamy; Anburajan, Parthiban; Kumar, Gopalakrishnan; Bakonyi, Péter; Nemestóthy, Nándor; Bélafi-Bakó, Katalin; Kim, Sang-Hyoun

2016-08-01

The effects of antifoaming agents on fermentative hydrogen production using galactose in batch and continuous operations were investigated. Batch hydrogen production assays with LS-303 (dimethylpolysiloxane), LG-109 (polyalkylene), LG-126 (polyoxyethylenealkylene), and LG-299 (polyether) showed that the doses and types of antifoaming agents played a significant role in hydrogen production. During batch tests, LS-303 at 100μL/L resulted in the maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 2.5L/L-d and 1.08mol H2/mol galactoseadded, respectively. The following continuously stirred tank reactor operated at 12h HRT with LS-303 at 100μL/L showed a stable HPR and HY of 4.9L/L-d and 1.17mol H2/mol galactoseadded, respectively, which were higher than those found for the control reactor. Microbial community analysis supported the alterations in H2 generation under different operating conditions and the stimulatory impact of certain antifoaming chemicals on H2 production was demonstrated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design of Mixed Batch Reactor and Column Studies at Oak Ridge National Laboratory

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

Wu, Weimin; Criddle, Craig S.

2015-11-16

We (the Stanford research team) were invited as external collaborators to contribute expertise in environmental engineering and field research at the ORNL IFRC, Oak Ridge, TN, for projects carried out at the Argonne National Laboratory and funded by US DOE. Specifically, we assisted in the design of batch and column reactors using ORNL IFRC materials to ensure the experiments were relevant to field conditions. During the funded research period, we characterized ORNL IFRC groundwater and sediments in batch microcosm and column experiments conducted at ANL, and we communicated with ANL team members through email and conference calls and face-to-face meetingsmore » at the annual ERSP PI meeting and national meetings. Microcosm test results demonstrated that U(VI) in sediments was reduced to U(IV) when amended with ethanol. The reduced products were not uraninite but unknown U(IV) complexes associated with Fe. Fe(III) in solid phase was only partially reduced. Due to budget reductions at ANL, Stanford contributions ended in 2011.« less

Effects of interfacial interaction on the properties of poly(vinyl chloride)/styrene-butadiene rubber blends

NASA Astrophysics Data System (ADS)

Zhu, Shuihan

PVC/SBR blends---new thermoplastic elastomer material---were developed. They have potential applications due to low costs and low-temperature elasticity. A unique compatibilization method was employed to enhance the mechanical properties of the materials a compatibilizer miscible with one of the blend components can react chemically with the other component(s). Improvements in tensile and impact behavior were observed as a result of the compatibilization. A novel characterization technique to study the interface of PVC/SBR blends was developed. This technique involves the observation of the unstained sample under electron beam irradiation by a transmission electron microscope (TEM). An enrichment of rubber at the interface between PVC and SBR was detected in the compatiblized PVC/SBR blends. Magnetic relaxation measurements show that the rubber concentration in the proximity of PVC increases with the degree of covulcanization between NBR and SBR. The interface development and the rheological effect during processing were investigated. The interfacial concentration profile and the interfacial thickness were obtained by grayscale measurements on TEM micrographs, evaluation of SIMS images, and measurements of micromechanical properties.

A subagging regression method for estimating the qualitative and quantitative state of groundwater

NASA Astrophysics Data System (ADS)

Jeong, Jina; Park, Eungyu; Han, Weon Shik; Kim, Kue-Young

2017-08-01

A subsample aggregating (subagging) regression (SBR) method for the analysis of groundwater data pertaining to trend-estimation-associated uncertainty is proposed. The SBR method is validated against synthetic data competitively with other conventional robust and non-robust methods. From the results, it is verified that the estimation accuracies of the SBR method are consistent and superior to those of other methods, and the uncertainties are reasonably estimated; the others have no uncertainty analysis option. To validate further, actual groundwater data are employed and analyzed comparatively with Gaussian process regression (GPR). For all cases, the trend and the associated uncertainties are reasonably estimated by both SBR and GPR regardless of Gaussian or non-Gaussian skewed data. However, it is expected that GPR has a limitation in applications to severely corrupted data by outliers owing to its non-robustness. From the implementations, it is determined that the SBR method has the potential to be further developed as an effective tool of anomaly detection or outlier identification in groundwater state data such as the groundwater level and contaminant concentration.

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.

[Optimization Study on the Nitrogen and Phosphorus Removal of Modified Two- sludge System Under the Condition of Low Carbon Source].

PubMed

Yang, Wei-qiang; Wang, Dong-bo; Li, Xiao-ming; Yang, Qi; Xu, Qiu-xiang; Zhang, Zhi-bei; Li, Zhi-jun; Xiang, Hai-hong; Wang, Ya-li; Sun, Jian

2016-04-15

This paper explored the method of resolving insufficient carbon source in urban sewage by comparing and analyzing denitrification and phosphorus removal (NPR) effect between modified two-sludge system and traditional anaerobic-aerobic-anoxic process under the condition of low carbon source wastewater. The modified two-sludge system was the experimental reactor, which was optimized by adding two stages of micro-aeration (aeration rate 0.5 L · mm⁻¹) in the anoxic period of the original two-sludge system, and multi-stage anaerobic-aerobic-anoxic SBR was the control reactor. When the influent COD, ammonia nitrogen, SOP concentration were respectively 200, 35, 10 mg · L⁻¹, the NPR effect of the experimental reactor was hetter than that of thecontrol reactor with the removal efficiency of TN being 94.8% vs 60.9%, and TP removal being 96.5% vs 75%, respectively. The effluent SOP, ammonia, TN concentration of the experimental reactor were 0.35, 0.50, 1.82 mg · L⁻¹, respectively, which could fully meet the first class of A standard of the Pollutants Emission Standard of Urban Wastewater Treatment Firm (GB 18918-2002). Using the optimized treatment process, the largest amounts of nitrogen and phosphorus removal per unit carbon source (as COD) were 0.17 g · g⁻¹ and 0.048 g · g⁻¹ respectively, which could furthest solve the lower carbon concentration in current municipal wastewater.

Pyrolysis of waste tyres: A review

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

Williams, Paul T., E-mail: p.t.williams@leeds.ac.uk

2013-08-15

Graphical abstract: - Highlights: • Pyrolysis of waste tyres produces oil, gas and char, and recovered steel. • Batch, screw kiln, rotary kiln, vacuum and fluidised-bed are main reactor types. • Product yields are influenced by reactor type, temperature and heating rate. • Pyrolysis oils are complex and can be used as chemical feedstock or fuel. • Research into higher value products from the tyre pyrolysis process is reviewed. - Abstract: Approximately 1.5 billion tyres are produced each year which will eventually enter the waste stream representing a major potential waste and environmental problem. However, there is growing interest inmore » pyrolysis as a technology to treat tyres to produce valuable oil, char and gas products. The most common reactors used are fixed-bed (batch), screw kiln, rotary kiln, vacuum and fluidised-bed. The key influence on the product yield, and gas and oil composition, is the type of reactor used which in turn determines the temperature and heating rate. Tyre pyrolysis oil is chemically very complex containing aliphatic, aromatic, hetero-atom and polar fractions. The fuel characteristics of the tyre oil shows that it is similar to a gas oil or light fuel oil and has been successfully combusted in test furnaces and engines. The main gases produced from the pyrolysis of waste tyres are H{sub 2}, C{sub 1}–C{sub 4} hydrocarbons, CO{sub 2}, CO and H{sub 2}S. Upgrading tyre pyrolysis products to high value products has concentrated on char upgrading to higher quality carbon black and to activated carbon. The use of catalysts to upgrade the oil to a aromatic-rich chemical feedstock or the production of hydrogen from waste tyres has also been reported. Examples of commercial and semi-commercial scale tyre pyrolysis systems show that small scale batch reactors and continuous rotary kiln reactors have been developed to commercial scale.« less

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

Brown, Nicholas R.; Worrall, Andrew; Todosow, Michael

Small modular reactors (SMRs) offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of SMRs on nuclear fuel cycle performance. The focus of this paper is the fuel cycle impacts of light water SMRs in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary example reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Options Campaign. The hypothetical light water SMR example case considered in these preliminary scoping studies ismore » a cartridge type one-batch core with slightly less than 5.0% enrichment. Challenges associated with SMRs include increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burnup in the reactor and the fuel cycle performance. This paper summarizes a list of the factors relevant to SMR fuel, core, and operation that will impact fuel cycle performance. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burnup of the reactor. Fuel cycle performance metrics for a hypothetical example SMR are compared with those for a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. The metrics performance for such an SMR is degraded for the mass of spent nuclear fuel and high-level waste disposed of, mass of depleted uranium disposed of, land use per energy generated, and carbon emissions per energy generated. Finally, it is noted that the features of some SMR designs impact three main aspects of fuel cycle performance: (1) small cores which means high leakage (there is a radial and axial component), (2) no boron which means heterogeneous core and extensive use of control rods and BPs, and (3) single batch cores. But not all of the SMR designs have all of these traits. As a result, the approach used in this study is therefore a bounding case and not all SMRs may be affected to the same extent.« less

Continuous xylose fermentation by Candida shehatae in a two-stage reactor

Treesearch

M. A. Alexander; T. W. Chapman; T. W. Jeffries

1988-01-01

Recent work has identified ethanol toxicity as a major factor preventing continuous production of ethanol at the concentrations obtainable in batch culture. In this paper we investigate the use of a continuous two-stage bioreactor design to circumvent toxic effects of ethanol. Biomass is produced via continuous culture in the first stage reactor in which ethanol...

Microfluidic Synthesis and Biological Evaluation of Photothermal Biodegradable Copper Sulfide Nanoparticles.

PubMed

Ortiz de Solorzano, Isabel; Prieto, Martín; Mendoza, Gracia; Alejo, Teresa; Irusta, Silvia; Sebastian, Victor; Arruebo, Manuel

2016-08-24

The continuous synthesis of biodegradable photothermal copper sulfide nanoparticles has been carried out with the aid of a microfluidic platform. A comparative physicochemical characterization of the resulting products from the microreactor and from a conventional batch reactor has been performed. The microreactor is able to operate in a continuous manner and with a 4-fold reduction in the synthesis times compared to that of the conventional batch reactor producing nanoparticles with the same physicochemical requirements. Biodegradation subproducts obtained under simulated physiological conditions have been identified, and a complete cytotoxicological analysis on different cell lines was performed. The photothermal effect of those nanomaterials has been demonstrated in vitro as well as their ability to generate reactive oxygen species.

The catalytic activity of CoMo/USY on deoxygenation reaction of anisole in a batch reactor

NASA Astrophysics Data System (ADS)

Nugrahaningtyas, K. D.; Putri, I. F.; Heraldy, E.; Hidayat, Y.

2018-04-01

The catalytic hydrodeoxigenation of the bio oil model compounds (biomass pyrolysis results) typically uses sulphide catalysts. In this study, we studied the activity of non-sulphide catalyst, the effect of temperature and reaction time on anisole deoxygenation. The catalytic activity was performed in a batch reactor, using N2 gas at 1 bar of pressure. The product was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The result showed that the Co-Mo/USY catalyst perform a highest activity and produce pentamethylbenzene, an oxygen free products, when reaction time is 2 hours. The Co-Mo/USY catalysts has the value of the total yield of the product increased with time increase drastically.

Biodegradation of pharmaceuticals in hospital wastewater by a hybrid biofilm and activated sludge system (Hybas).

PubMed

Escolà Casas, Mònica; Chhetri, Ravi Kumar; Ooi, Gordon; Hansen, Kamilla M S; Litty, Klaus; Christensson, Magnus; Kragelund, Caroline; Andersen, Henrik R; Bester, Kai

2015-10-15

Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process (hybrid biofilm and activated sludge system (Hybas™)) has been suggested as a possible solution for hospital wastewater treatment. To investigate the potential of such a hybrid system for the removal of pharmaceuticals in hospital wastewater a pilot plant consisting of a series of one activated sludge reactor, two Hybas™ reactors and one moving bed biofilm reactor (MBBR) has been established and adapted during 10 months of continuous operation. After this adaption phase batch and continuous experiments were performed for the determination of degradation of pharmaceuticals. Removal of organic matter and nitrification mainly occurred in the first reactor. Most pharmaceuticals were removed significantly. The removal of pharmaceuticals (including X-ray contrast media, β-blockers, analgesics and antibiotics) was fitted to a single first-order kinetics degradation function, giving degradation rate constants from 0 to 1.49 h(-1), from 0 to 7.78 × 10(-1)h(-1), from 0 to 7.86 × 10(-1)h(-1) and from 0 to 1.07 × 10(-1)h(-1) for first, second, third and fourth reactors respectively. Generally, the highest removal rate constants were found in the first and third reactors while the lowest were found in the second one. When the removal rate constants were normalized to biomass amount, the last reactor (biofilm only) appeared to have the most effective biomass in respect to removing pharmaceuticals. In the batch experiment, out of 26 compounds, 16 were assessed to degrade more than 20% of the respective pharmaceutical within the Hybas™ train. In the continuous flow experiments, the measured removals were similar to those estimated from the batch experiments, but the concentrations of a few pharmaceuticals appeared to increase during the first treatment step. Such increase could be attributed to de-conjugation or formation from other metabolites. Copyright © 2015 Elsevier B.V. All rights reserved.

Growth kinetics of the photosynthetic bacterium Chlorobium thiosulfatophilum in a fed-batch reactor.

PubMed

Kim, B W; Chang, H N; Kim, I K; Lee, K S

1992-08-01

Hydrogen sulfide dissolved in water can be converted to elementary sulfur or sulfate by the photosynthetic bacterium Chlorobium thiosulfatophilum. Substrate inhibition occurred at sulfide concentrations above 5.7 mM. Light inhibition was found at average light intensities of 40,000 lux in a sulfide concentration of 5 mM, where no substrate inhibition occurred. Light intensity, the most important growth parameter, was attenuated through both scattering by sulfur particles and absorption by the cells. Average cell and sulfur particle sizes were 1.1 and 9.4 microm, respectively. Cells contributed 10 times as much to the turbidity as sulfur particles of the same weight concentration. The light attenuation factor was mathematically modeled, considering both the absorption and scattering effects based on the Beer-Lambert law and the Rayleigh theory, which were introduced to the cell growth model. Optimal operational conditions relating feed rate vs. light intensity were obtained to suppress the accumulation of sulfate and sulfide and save light energy for 2- and 4-L fed-batch reactors. Light intensity should be greater for the same performance (H(2)S removal rate/unit cell concentration) in larger reactors due to the scaleup effect on light transmission. Knowledge of appropriate growth kinetics in photosynthetic fed-batch reactors was essential to increase feed rate and light intensity and therefore cell growth. A mathematical model was developed that describes the cell growth by considering the light attenuation factor due to scattering and absorption and the crowding effect of the cells. This model was in good agreement with the experimental results. (c) 1992 John Wiley & Sons, Inc.

Pressure-accelerated azide-alkyne cycloaddition: micro capillary versus autoclave reactor performance.

PubMed

Borukhova, Svetlana; Seeger, Andreas D; Noël, Timothy; Wang, Qi; Busch, Markus; Hessel, Volker

2015-02-01

Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and limitations of microflow equipment under standard conditions are well established. Herein, we apply novel-process-window (NPWs) principles, such as intensification of intrinsic kinetics of a reaction using high temperature, pressure, and concentration, on azide-alkyne cycloaddition towards synthesis of Rufinamide precursor. We applied three main activation methods (i.e., uncatalyzed batch, uncatalyzed flow, and catalyzed flow) on uncatalyzed and catalyzed azide-alkyne cycloaddition. We compare the performance of two reactors, a specialized autoclave batch reactor for high-pressure operation up to 1800 bar and a capillary flow reactor (up to 400 bar). A differentiated and comprehensive picture is given for the two reactors and the three methods of activation. Reaction speedup and consequent increases in space-time yields is achieved, while the process window for favorable operation to selectively produce Rufinamide precursor in good yields is widened. The best conditions thus determined are applied to several azide-alkyne cycloadditions to widen the scope of the presented methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recycling of hazardous solid waste material using high-temperature solar process heat. 2. Reactor design and experimentation.

PubMed

Schaffner, Beatrice; Meier, Anton; Wuillemin, Daniel; Hoffelner, Wolfgang; Steinfeld, Aldo

2003-01-01

A novel high-temperature solar chemical reactor is proposed for the thermal recycling of hazardous solid waste material using concentrated solar power. It features two cavities in series, with the inner one functioning as the solar absorber and the outer one functioning as the reaction chamber. The solar reactor can handle thermochemical processes at temperatures above 1,300 K involving multiphases and controlled atmospheres. It further allows for batch or continuous mode of operation and for easy adjustment of the residence time of the reactants to match the kinetics of the reaction. A 10-kW solar reactor prototype was designed and tested for the carbothermic reduction of electric arc furnace dusts (EAFD). The reactor was subjected to mean solar flux intensities of 2,000 kW m(-2) and operated in both batch and continuous mode within the temperature range of 1,120-1,400 K. Extraction of over 90% of the toxic compounds originally contained in the EAFD was achieved while the condensable products of the off-gas contained mainly Zn, Pb, and Cl. The use of concentrated solar energy as the source of process heat offers the possibility of converting hazardous solid waste material into valuable commodities for processes in closed and sustainable material cycles.

Ultrasound pre-treatment for anaerobic digestion improvement.

PubMed

Pérez-Elvira, S; Fdz-Polanco, M; Plaza, F I; Garralón, G; Fdz-Polanco, F

2009-01-01

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT=20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT=15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR=20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3-10 kW per kW of energy used.

Contribution made by multivariate curve resolution applied to gel permeation chromatography-Fourier transform infrared data for an in-depth characterization of styrene-butadiene rubber blends.

PubMed

Ruckebusch, C; Vilmin, F; Coste, N; Huvenne, J P

2008-07-01

We evaluate the contribution made by multivariate curve resolution-alternating least squares (MCR-ALS) for resolving gel permeation chromatography-Fourier transform infrared (GPC-FT-IR) data collected on butadiene rubber (BR) and styrene butadiene rubber (SBR) blends in order to access in-depth knowledge of polymers along the molecular weight distribution (MWD). In the BR-SBR case, individual polymers differ in chemical composition but share almost the same MWD. Principal component analysis (PCA) gives a general overview of the data structure and attests to the feasibility of modeling blends as a binary system. MCR-ALS is then performed. It allows resolving the chromatographic coelution and validates the chosen methodology. For SBR-SBR blends, the problem is more challenging since the individual elastomers present the same chemical composition. Rank deficiency is detected from the PCA data structure analysis. MCR-ALS is thus performed on column-wise augmented matrices. It brings very useful insight into the composition of the analyzed blends. In particular, a weak change in the composition of individual SBR in the MWD's lowest mass region is revealed.

Focusing light through strongly scattering media using genetic algorithm with SBR discriminant

NASA Astrophysics Data System (ADS)

Zhang, Bin; Zhang, Zhenfeng; Feng, Qi; Liu, Zhipeng; Lin, Chengyou; Ding, Yingchun

2018-02-01

In this paper, we have experimentally demonstrated light focusing through strongly scattering media by performing binary amplitude optimization with a genetic algorithm. In the experiments, we control 160 000 mirrors of digital micromirror device to modulate and optimize the light transmission paths in the strongly scattering media. We replace the universal target-position-intensity (TPI) discriminant with signal-to-background ratio (SBR) discriminant in genetic algorithm. With 400 incident segments, a relative enhancement value of 17.5% with a ground glass diffuser is achieved, which is higher than the theoretical value of 1/(2π )≈ 15.9 % for binary amplitude optimization. According to our repetitive experiments, we conclude that, with the same segment number, the enhancement for the SBR discriminant is always higher than that for the TPI discriminant, which results from the background-weakening effect of SBR discriminant. In addition, with the SBR discriminant, the diameters of the focus can be changed ranging from 7 to 70 μm at arbitrary positions. Besides, multiple foci with high enhancement are obtained. Our work provides a meaningful reference for the study of binary amplitude optimization in the wavefront shaping field.

Enhancing mechanical and thermal properties of styrene-butadiene rubber/carboxylated acrylonitrile butadiene rubber blend by the usage of graphene oxide with diverse oxidation degrees

NASA Astrophysics Data System (ADS)

Xue, Xiaodong; Yin, Qing; Jia, Hongbing; Zhang, Xuming; Wen, Yanwei; Ji, Qingmin; Xu, Zhaodong

2017-11-01

Graphene oxide (GO) with various oxidation degrees were prepared through a modified Hummer's method by varying the dosage of oxidizing agent. Styrene-butadiene rubber (SBR)/carboxylated acrylonitrile butadiene rubber (XNBR)/GO nanocomposites were fabricated by aqueous-phase mixing of GO colloidal dispersion with SBR latex and a small loading of XNBR latex, followed by co-coagulation. Effects of GO oxidation degree on the morphology, structure, mechanical and thermal properties of nanocomposites were thoroughly investigated. The results showed that the mechanical strength of nanocomposites were enhanced with the increase of oxidation degree of GO. Especially, when the weight ratio of KMnO4 to graphite was 15/5, the tensile strength, tear strength and thermal conductivity of SBR/XNBR/GO filled with 3 phr (parts per hundred rubber) GO increased by 255.3%, 141.5% and 22.8%, respectively, compared to those of neat SBR/XNBR blend. In addition, the thermal stability and the solvent resistance of the nanocomposites were also improved significantly. This work suggested that GO with higher oxidation degree could effectively improve the properties of SBR/XNBR blend.

Friction characteristics of 20 x 4.4, type 7, aircraft tires constructed with different tread rubber compounds

NASA Technical Reports Server (NTRS)

Dreher, R. C.; Yager, T. J.

1976-01-01

A test program was conducted at the Langley aircraft landing loads and traction facility to evaluate the friction characteristics of 20 x 4.4, type, aircraft tires constructed with experimental cut-resistant, tread rubber compounds. These compounds consisted of different blends of natural rubber (NR) and an alfin catalyzed styrene-butadiene copolymer rubber (SBR). One tire having a blend of 30 SBR and 70 NR and another having a blend of 60 SBR and 40 NR in the tread were tested together with a standard production tire with no SBR content in the tread rubber. The results of this investigation indicated that the test tires constructed with the special cut-resistant tread rubber compositions did not suffer any significant degradation in tire friction capability when compared with the standard tire. In general, tire friction capability decreased with increasing speed and surface wetness condition. As yaw angle increased, tire braking capability decreased while tire cornering capability increased. Tread-wear data based on number of brake cycles, however, suggested that the tires with alfin SBR blends experienced significantly greater wear than the standard production tire.

Study of dynamics of glucose-glucose oxidase-ferricyanide reaction

NASA Astrophysics Data System (ADS)

Nováková, A.; Schreiberová, L.; Schreiber, I.

2011-12-01

This work is focused on dynamics of the glucose-glucose oxidase-ferricyanide enzymatic reaction with or without sodium hydroxide in a continuous-flow stirred tank reactor (CSTR) and in a batch reactor. This reaction exhibits pH-variations having autocatalytic character and is reported to provide nonlinear dynamic behavior (bistability, excitability). The dynamical behavior of the reaction was examined within a wide range of inlet parameters. The main inlet parameters were the ratio of concentrations of sodium hydroxide and ferricyanide and the flow rate. In a batch reactor we observed an autocatalytic drop of pH from slightly basic to medium acidic values. In a CSTR our aim was to find bistability in the presence of sodium hydroxide. However, only a basic steady state was found. In order to reach an acidic steady state, we investigated the system in the absence of sodium hydroxide. Under these conditions the transition from the basic to the acidic steady state was observed when inlet glucose concentration was increased.

Electrical resistivity tomography to quantify in situ liquid content in a full-scale dry anaerobic digestion reactor.

PubMed

André, L; Lamy, E; Lutz, P; Pernier, M; Lespinard, O; Pauss, A; Ribeiro, T

2016-02-01

The electrical resistivity tomography (ERT) method is a non-intrusive method widely used in landfills to detect and locate liquid content. An experimental set-up was performed on a dry batch anaerobic digestion reactor to investigate liquid repartition in process and to map spatial distribution of inoculum. Two array electrodes were used: pole-dipole and gradient arrays. A technical adaptation of ERT method was necessary. Measured resistivity data were inverted and modeled by RES2DINV software to get resistivity sections. Continuous calibration along resistivity section was necessary to understand data involving sampling and physicochemical analysis. Samples were analyzed performing both biochemical methane potential and fiber quantification. Correlations were established between the protocol of reactor preparation, resistivity values, liquid content, methane potential and fiber content representing liquid repartition, high methane potential zones and degradations zones. ERT method showed a strong relevance to monitor and to optimize the dry batch anaerobic digestion process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Critical analysis of submerged membrane sequencing batch reactor operating conditions.

PubMed

McAdam, Ewan; Judd, Simon J; Gildemeister, René; Drews, Anja; Kraume, Matthias

2005-10-01

To evaluate the Submerged Membrane Sequencing Batch Reactor process, several short-term studies were conducted to define critical flux, membrane aeration and intermittent filtration operation. Critical flux trials indicated that as mixed liquor suspended solids increased in concentration so would the propensity for membrane fouling. Consequently in order to characterise the impact of biomass concentration increase (that develops during permeate withdrawal) upon submerged microfiltration operation, two longer term studies were conducted, one with a falling hydraulic head and another with a continuous hydraulic head (as in membrane bio-reactors). Trans membrane pressure data was used to predict the maximum possible operating periods at 10 and 62 days for the falling hydraulic head and continuous hydraulic head respectively. Further analysis revealed that falling hydraulic head operation would require 21% more aeration to maintain a consistent crossflow velocity than continuous operation and would rely on pumping for full permeate withdrawal 80% earlier. This study concluded that further optimisation would be required to make this technology technically and economically viable.

Feasibility of bioengineered two-stages sequential batch reactor and filtration-adsorption process for complex agrochemical effluent.

PubMed

Manekar, Pravin; Biswas, Rima; Urewar, Chaitali; Pal, Sukdeb; Nandy, Tapas

2013-11-01

In the present study, the feasibility of a bioengineered two-stages sequential batch reactor (BTSSBR) followed by filtration-adsorption process was investigated to treat the agrochemical effluent by overcoming factor affecting process stability such as microbial imbalance and substrate sensitivity. An air stripper stripped 90% of toxic ammonia, and combined with other streams for bio-oxidation and filtration-adsorption. The BTSSBR system achieved bio-oxidation at 6 days hydraulic retention time by fending off microbial imbalance and substrate sensitivity. The maximum reduction in COD and BOD by heterotrophic bacteria in the first reactor was 87% and 90%, respectively. Removal of toxic ammoniacal-nitrogen by autotrophic bacteria in a post-second stage bio-oxidation was 97%. The optimum filtration and adsorption of pollutants were achieved at a filtration rate of 10 and 9 m(3)m(-2)h(-1), respectively. The treatment scheme comprising air stripper, BTSSBR and filtration-adsorption process showed a great promise for treating the agrochemical effluent. Copyright © 2013 Elsevier Ltd. All rights reserved.

3-Chloro-1,2-propanediol biodegradation by Ca-alginate immobilized Pseudomonas putida DSM 437 cells applying different processes: mass transfer effects.

PubMed

Konti, Aikaterini; Mamma, Diomi; Hatzinikolaou, Dimitios G; Kekos, Dimitris

2016-10-01

3-Chloro-1,2-propanediol (3-CPD) biodegradation by Ca-alginate immobilized Pseudomonas putida cells was performed in batch system, continuous stirred tank reactor (CSTR), and packed-bed reactor (PBR). Batch system exhibited higher biodegradation rates and 3-CPD uptakes compared to CSTR and PBR. The two continuous systems (CSTR and PBR) when compared at 200 mg/L 3-CPD in the inlet exhibited the same removal of 3-CPD at steady state. External mass-transfer limitations are found negligible at all systems examined, since the observable modulus for external mass transfer Ω ≪ 1 and the Biot number Bi > 1. Intra-particle diffusion resistance had a significant effect on 3-CPD biodegradation in all systems studied, but to a different extent. Thiele modulus was in the range of 2.5 in batch system, but it was increased at 11 when increasing cell loading in the beads, thus lowering significantly the respective effectiveness factor. Comparing the systems at the same cell loading in the beads PBR was less affected by internal diffusional limitations compared to CSTR and batch system, and, as a result, exhibited the highest overall effectiveness factor.

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

Ford, JP; Thapaliya, N; Kelly, MJ

Fatty acids (FAs) derived via thermal hydrolysis of food-grade lard and canola oil were deoxygenated in the liquid phase using a commercially available 5 wt % Pd/C catalyst. Online quadrupole mass spectrometry and gas chromatography were used to monitor the effluent gases from the semi-batch stirred autoclave reactors. Stearic, oleic, and palmitic acids were employed as model compounds. A catalyst lifetime exceeding 2200 turnovers for oleic acid deoxygenation was demonstrated at 300 degrees C and 15 atm under 10% H-2. The initial decarboxylation rate of palmitic acid under 5% H-2 decreases sharply with increasing initial concentration; in contrast, the initialmore » decarbonylation rate increases linearly, indicative of first-order kinetics. Scale-up of diesel-range hydrocarbon production was investigated by increasing the reactor vessel size, initial FA concentration, and FA/catalyst mass ratio. Lower CO2 selectivity and batch productivity were observed at the larger scales (600 and 5000 mL), primarily because of the higher initial FA concentration (67 wt %) employed. Because unsaturated FAs must be hydrogenated before deoxygenation can proceed at an appreciable rate, the additional batch time required for FA hydrogenation reduces the batch productivity for unsaturated feedstocks. Low-temperature hydrogenation of unsaturated feedstocks (using Pd/C or another less-expensive catalyst) prior to deoxygenation is recommended.« less

Removal and recovery of uranium(VI) by waste digested activated sludge in fed-batch stirred tank reactor.

PubMed

Jain, Rohan; Peräniemi, Sirpa; Jordan, Norbert; Vogel, Manja; Weiss, Stephan; Foerstendorf, Harald; Lakaniemi, Aino-Maija

2018-05-24

This study demonstrated the removal and recovery of uranium(VI) in a fed-batch stirred tank reactor (STR) using waste digested activated sludge (WDAS). The batch adsorption experiments showed that WDAS can adsorb 200 (±9.0) mg of uranium(VI) per g of WDAS. The maximum adsorption of uranium(VI) was achieved even at an acidic initial pH of 2.7 which increased to a pH of 4.0 in the equilibrium state. Desorption of uranium(VI) from WDAS was successfully demonstrated from the release of more than 95% of uranium(VI) using both acidic (0.5 M HCl) and alkaline (1.0 M Na 2 CO 3 ) eluents. Due to the fast kinetics of uranium(VI) adsorption onto WDAS, the fed-batch STR was successfully operated at a mixing time of 15 min. Twelve consecutive uranium(VI) adsorption steps with an average adsorption efficiency of 91.5% required only two desorption steps to elute more than 95% of uranium(VI) from WDAS. Uranium(VI) was shown to interact predominantly with the phosphoryl and carboxyl groups of the WDAS, as revealed by in situ infrared spectroscopy and time-resolved laser-induced fluorescence spectroscopy studies. This study provides a proof-of-concept of the use of fed-batch STR process based on WDAS for the removal and recovery of uranium(VI). Copyright © 2018 Elsevier Ltd. All rights reserved.

Optimization of L-(+)-lactic acid production by ring and disc plastic composite supports through repeated-batch biofilm fermentation.

PubMed Central

Ho, K L; Pometto, A L; Hinz, P N

1997-01-01

Four customized bioreactors, three with plastic composite supports (PCS) and one with suspended cells (control), were operated as repeated-batch fermentors for 66 days at pH 5 and 37 degrees C. The working volume of each customized reactor was 600 ml, and each reactor's medium was changed every 2 to 5 days for 17 batches. The performance of PCS bioreactors in long-term biofilm repeated-batch fermentation was compared with that of suspended-cell bioreactors in this research. PCS could stimulate biofilm formation, supply nutrients to attached and free suspended cells, and reduce medium channelling for lactic acid production. Compared with conventional repeated-batch fermentation, PCS bioreactors shortened the lag time by threefold (control, 11 h; PCS, 3.5 h) and sixfold (control, 9 h; PCS, 1.5 h) at yeast extract concentrations of 0.4 and 0.8% (wt/vol), respectively. They also increased the lactic acid productivity of Lactobacillus casei subsp. rhamnosus (ATCC 11443) by 40 to 70% and shortened the total fermentation time by 28 to 61% at all yeast extract concentrations. The fastest productivity of the PCS bioreactors (4.26 g/liter/h) was at a starting glucose concentration of 10% (wt/vol), whereas that of the control (2.78 g/liter/h) was at 8% (wt/vol). PCS biofilm lactic acid fermentation can drastically improve the fermentation rate with reduced complex-nutrient addition. PMID:9212403

Operational Test Report (OTR): On-Site Degradation of Oily Sludge in a Tenthousand Gallon Sequencing Batch Reactor at Navsta Pearl Harbor, HI

DTIC Science & Technology

2003-11-01

treated anaerobically . To accommodate the longer residence times needed to treat waste anaerobically , the capacity is often much larger than a...the receiving tank (T1), where it is diluted and run through a trash pump (P1) to produce a homogenous slurry. 3 Figure 1. Sequencing...blower provides air to the reactor and receiving tank. The trash pump is also used to transfer sludge to the reactor and to recirculate sludge in

Dioscorea spp. (A Wild Edible Tuber): A Study on Its Ethnopharmacological Potential and Traditional Use by the Local People of Similipal Biosphere Reserve, India

PubMed Central

Kumar, Sanjeet; Das, Gitishree; Shin, Han-Seung; Patra, Jayanta Kumar

2017-01-01

A number of wild crops remain unexplored in this world and among them some have excellent medicinal and nutritional properties. India is a harbor of biodiversity in general and phytodiversity in particular. The plant diversity is distributed from the Western Ghats to Eastern Ghats, along with the North-Eastern region and from the Greater Himalayas to the plain of Ganga. Among these distributed floral regions of the country, the Eastern Ghats are important due to their rich floral diversity. The forests of Odisha form a major part of Eastern Ghats in general and the Similipal Biosphere Reserve (SBR) in particular. The SBR is inhabited by many local communities. The food and medicinal habits of these communities are not fully explored even today. They are dependent on the forests of SBR for their food and medicine. Among their collections from forests, root and tuberous plants play a significant role. The local communities of SBR use about 89 types of tuberous plants for various purposes. Dioscorea is one such tuber, having maximum use among the local of SBR. However, less documentation and no specific reports are available on the food and medicinal values of the species available in this part of the World. Dioscorea species, popularly known as Yam worldwide and as Ban Aalu in Odisha, India, is a prime staple medicinal-food substitute for the majority of rural and local people of the state of India. Of the 13 Dioscorea species available in SBR, 10 species are known to be bitter in taste and unpalatable when taken raw. Since less documentation is available on the Dioscorea species of SBR and their traditional uses, the present study was focused on the ethnobotany, nutritional and pharmacological values of these species along its nutraceutical importance. PMID:28261094

Dioscorea spp. (A Wild Edible Tuber): A Study on Its Ethnopharmacological Potential and Traditional Use by the Local People of Similipal Biosphere Reserve, India.

PubMed

Kumar, Sanjeet; Das, Gitishree; Shin, Han-Seung; Patra, Jayanta Kumar

2017-01-01

A number of wild crops remain unexplored in this world and among them some have excellent medicinal and nutritional properties. India is a harbor of biodiversity in general and phytodiversity in particular. The plant diversity is distributed from the Western Ghats to Eastern Ghats, along with the North-Eastern region and from the Greater Himalayas to the plain of Ganga. Among these distributed floral regions of the country, the Eastern Ghats are important due to their rich floral diversity. The forests of Odisha form a major part of Eastern Ghats in general and the Similipal Biosphere Reserve (SBR) in particular. The SBR is inhabited by many local communities. The food and medicinal habits of these communities are not fully explored even today. They are dependent on the forests of SBR for their food and medicine. Among their collections from forests, root and tuberous plants play a significant role. The local communities of SBR use about 89 types of tuberous plants for various purposes. Dioscorea is one such tuber, having maximum use among the local of SBR. However, less documentation and no specific reports are available on the food and medicinal values of the species available in this part of the World. Dioscorea species, popularly known as Yam worldwide and as Ban Aalu in Odisha, India, is a prime staple medicinal-food substitute for the majority of rural and local people of the state of India. Of the 13 Dioscorea species available in SBR, 10 species are known to be bitter in taste and unpalatable when taken raw. Since less documentation is available on the Dioscorea species of SBR and their traditional uses, the present study was focused on the ethnobotany, nutritional and pharmacological values of these species along its nutraceutical importance.

X-ray Analysis of Defects and Anomalies in AGR-5/6/7 TRISO Particles

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

Helmreich, Grant W.; Hunn, John D.; Skitt, Darren J.

2017-06-01

Coated particle fuel batches J52O-16-93164, 93165, 93166, 93168, 93169, 93170, and 93172 were produced by Babcock and Wilcox Technologies (BWXT) for possible selection as fuel for the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program’s AGR-5/6/7 irradiation test in the Idaho National Laboratory (INL) Advanced Test Reactor (ATR), or may be used for other tests. Each batch was coated in a 150-mm-diameter production-scale fluidized-bed chemical vapor deposition (CVD) furnace. Tristructural isotropic (TRISO) coatings were deposited on 425-μm-nominal-diameter spherical kernels from BWXT lot J52R-16-69317 containing a mixture of 15.4%-enriched uranium carbide and uranium oxide (UCO), with the exception of Batchmore » 93164, which used similar kernels from BWXT lot J52L-16-69316. The TRISO-coatings consisted of a ~50% dense carbon buffer layer with 100-μmnominal thickness, a dense inner pyrolytic carbon (IPyC) layer with 40-μm-nominal thickness, a silicon carbide (SiC) layer with 35-μm-nominal thickness, and a dense outer pyrolytic carbon (OPyC) layer with 40-μm-nominal thickness. Each coated particle batch was sieved to upgrade the particles by removing over-sized and under-sized material, and the upgraded batch was designated by appending the letter A to the end of the batch number (e.g., 93164A). Secondary upgrading by sieving was performed on the upgraded batches to remove specific anomalies identified during analysis for Defective IPyC, and the upgraded batches were designated by appending the letter B to the end of the batch number (e.g., 93165B). Following this secondary upgrading, coated particle composite J52R-16-98005 was produced by BWXT as fuel for the AGR Program’s AGR-5/6/7 irradiation test in the INL ATR. This composite was comprised of coated particle fuel batches J52O-16-93165B, 93168B, 93169B, and 93170B.« less

Bioelectrochemical sulphate reduction on batch reactors: Effect of inoculum-type and applied potential on sulphate consumption and pH.

PubMed

Gacitúa, Manuel A; Muñoz, Enyelbert; González, Bernardo

2018-02-01

Microbial electrolysis batch reactor systems were studied employing different conditions, paying attention on the effect that biocathode potential has on pH and system performance, with the overall aim to distinguish sulphate reduction from H 2 evolution. Inocula from pure strains (Desulfovibrio paquesii and Desulfobacter halotolerans) were compared to a natural source conditioned inoculum. The natural inoculum possess the potential for sulphate reduction on serum bottles experiments due to the activity of mutualistic bacteria (Sedimentibacter sp. and Bacteroides sp.) that assist sulphate-reducing bacterial cells (Desulfovibrio sp.) present in the consortium. Electrochemical batch reactors were monitored at two different potentials (graphite-bar cathodes poised at -900 and -400mV versus standard hydrogen electrode) in an attempt to isolate bioelectrochemical sulphate reduction from hydrogen evolution. At -900mV all inocula were able to reduce sulphate with the consortium demonstrating superior performance (SO 4 2- consumption: 25.71gm -2 day -1 ), despite the high alkalinisation of the media. At -400mV only the pure Desulfobacter halotolerans inoculated system was able to reduce sulphate (SO 4 2- consumption: 17.47gm -2 day -1 ) and, in this potential condition, pH elevation was less for all systems, confirming direct (or at least preferential) bioelectrochemical reduction of sulphate over H 2 production. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance of asphaltic concrete incorporating styrene butadiene rubber subjected to varying aging condition

NASA Astrophysics Data System (ADS)

Salah, Faisal Mohammed; Jaya, Ramadhansyah Putra; Mohamed, Azman; Hassan, Norhidayah Abdul; Rosni, Nurul Najihah Mad; Mohamed, Abdullahi Ali; Agussabti

2017-12-01

The influence of styrene butadiene rubber (SBR) on asphaltic concrete properties at different aging conditions was presented in this study. These aging conditions were named as un-aged, short-term, and long-term aging. The conventional asphalt binder of penetration grade 60/70 was used in this work. Four different levels of SBR addition were employed (i.e., 0 %, 1 %, 3 %, and 5 % by binder weight). Asphalt concrete mixes were prepared at selected optimum asphalt content (5 %). The performance was evaluated based on Marshall Stability, resilient modulus, and dynamic creep tests. Results indicated the improving stability and permanent deformation characteristics that the mixes modified with SBR polymer have under aging conditions. The result also showed that the stability, resilient modulus, and dynamic creep tests have the highest rates compared to the short-term aging and un-aged samples. Thus, the use of 5 % SBR can produce more durable asphalt concrete mixtures with better serviceability.

Recycling of the Electronic Waste Applying the Plasma Reactor Technology

NASA Astrophysics Data System (ADS)

Lázár, Marián; Jasminská, Natália; Čarnogurská, Mária; Dobáková, Romana

2016-12-01

The following paper discusses a high-temperature gasification process and melting of electronic components and computer equipment using plasma reactor technology. It analyses the marginal conditions of batch processing, as well as the formation of solid products which result from the procedure of waste processing. Attention is also paid to the impact of the emerging products on the environment.

Enhanced organics and nitrogen removal in batch-operated vertical flow constructed wetlands by combination of intermittent aeration and step feeding strategy.

PubMed

Fan, Jinlin; Liang, Shuang; Zhang, Bo; Zhang, Jian

2013-04-01

Oxygen and carbon source supply are usually insufficient in subsurface flow constructed wetlands. Simultaneous removal of organic pollutants and nitrogen in five batch-operated vertical flow constructed wetlands under different operating conditions was investigated. Alternate aerobic and anaerobic regions were created well with intermittent aeration. Four-month experiments showed that the wetland-applied intermittent aeration combined with step feeding strategy (reactor E) greatly improved the removal of organics, ammonium nitrogen (NH4-N), and total nitrogen (TN) simultaneously, which were 97, 96, and 82%, respectively. It was much better than non-aerated reactors A and B and outperformed intermittently aerated reactor D without step feeding. Continuous aeration (reactor C) significantly enhanced the organics removal and nitrification, but it limited the TN removal (29%) seriously as a result of low denitrification level, and the high operation cost remained a question. The effect of plants was confirmed in this study, and the monitoring data showed that the plants could grow normally. Intermittent aeration as well as step feeding had no obvious influence on the growth of wetland plants in this study.

Modeling for the optimal biodegradation of toxic wastewater in a discontinuous reactor.

PubMed

Betancur, Manuel J; Moreno-Andrade, Iván; Moreno, Jaime A; Buitrón, Germán; Dochain, Denis

2008-06-01

The degradation of toxic compounds in Sequencing Batch Reactors (SBRs) poses inhibition problems. Time Optimal Control (TOC) methods may be used to avoid such inhibition thus exploiting the maximum capabilities of this class of reactors. Biomass and substrate online measurements, however, are usually unavailable for wastewater applications, so TOC must use only related variables as dissolved oxygen and volume. Although the standard mathematical model to describe the reaction phase of SBRs is good enough for explaining its general behavior in uncontrolled batch mode, better details are needed to model its dynamics when the reactor operates near the maximum degradation rate zone, as when TOC is used. In this paper two improvements to the model are suggested: to include the sensor delay effects and to modify the classical Haldane curve in a piecewise manner. These modifications offer a good solution for a reasonable complexification tradeoff. Additionally, a new way to look at the Haldane K-parameters (micro(o),K(I),K(S)) is described, the S-parameters (micro*,S*,S(m)). These parameters do have a clear physical meaning and, unlike the K-parameters, allow for the statistical treatment to find a single model to fit data from multiple experiments.

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

Hazen Ed., T.C.

On behalf of the Subsurface Biogeochemical Research (SBR) program managers in the Climate and Environmental Sciences Division (CESD), Office of Biological and Environmental Research (BER), welcome to the 2011 SBR Principal Investigators meeting. Thank you in advance for your attendance and your presentations at this year's meeting. As the events in Japan continue to unfold, we are all reminded that the research we perform on radionuclide behavior in the environment has implications beyond legacy waste cleanup and in fact has its place in the discussion on the expanded use of nuclear power. As in the past, there are three broadmore » objectives to the Principal Investigators meeting: (1) to provide opportunities to share research results and promote interactions among the SBR scientists and other invited guests; (2) to evaluate the progress of each project within the program; and (3) to showcase the scientific expertise and research progress over the past year to senior managers within the DOE Office of Science, the technology offices within DOE, and other invited attendees from other Federal Agencies. This past year has seen a few significant changes within BER and within the SBR program. In November, our Associate Director for BER, Anna Palmisano, retired from Federal service. Just this month, Dr. Sharlene Weatherwax (Division Director for Biological Systems Sciences) has been named as the new Associate Director for BER. In August, BER welcomed Dr. Gary Geernaert as the new Division Director for CESD. Gary joins the division from Los Alamos National Laboratory with a background in atmospheric science. Within the SBR program, a new Strategic Plan was completed last June (currently posted on the SBR and the Office of Science website). The new strategic plan is intended to foster integration within the Environmental Systems Science portion of the BER budget that includes both SBR and Terrestrial Ecosystem Sciences (TES). Both these programs share a goal of advancing a predictive understanding of environmental processes and utilizing iterative, multidisciplinary approaches to understand complex environmental systems of relevance to DOE. CESD in general is undergoing continued discussions on integration among its programs in an effort to develop a new strategic plan for the division. This effort also includes identifying opportunities for integration with BER's Biological Systems Science Division (BSSD). The program this year includes three poster presentation sessions, six plenary sessions, and three breakout sessions. The plenary session on Tuesday morning will feature introductory presentations by BER program staff and three keynote addresses from Dr. Ken Bencala (USGS), Dr. Michael (Mick) Follows (MIT) and Dr. Sue Brantley (PSU) that will lead into three breakout sessions Tuesday afternoon. The breakout sessions are intended to highlight key developments in SBR research and foster a dialog among session participants on scientific paths forward in each particular area. The SBR program managers are asking for input from the SBR community at these sessions to help guide future efforts and/or identify areas of integration within BER programs. On Wednesday, plenary sessions will continue in the morning, followed by an early afternoon poster session. After an extended break for lunch, plenary sessions will continue in the afternoon, followed by an evening poster session. Thursday's plenary session will focus on selected highlights of research efforts at the IFRC sites and on a new potential TES field effort in the Arctic. This new field site is an obvious point of integration between the SBR and TES programs.« less

Noise suppression for dual-energy CT via penalized weighted least-square optimization with similarity-based regularization

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

Harms, Joseph; Wang, Tonghe; Petrongolo, Michael

Purpose: Dual-energy CT (DECT) expands applications of CT imaging in its capability to decompose CT images into material images. However, decomposition via direct matrix inversion leads to large noise amplification and limits quantitative use of DECT. Their group has previously developed a noise suppression algorithm via penalized weighted least-square optimization with edge-preservation regularization (PWLS-EPR). In this paper, the authors improve method performance using the same framework of penalized weighted least-square optimization but with similarity-based regularization (PWLS-SBR), which substantially enhances the quality of decomposed images by retaining a more uniform noise power spectrum (NPS). Methods: The design of PWLS-SBR is basedmore » on the fact that averaging pixels of similar materials gives a low-noise image. For each pixel, the authors calculate the similarity to other pixels in its neighborhood by comparing CT values. Using an empirical Gaussian model, the authors assign high/low similarity value to one neighboring pixel if its CT value is close/far to the CT value of the pixel of interest. These similarity values are organized in matrix form, such that multiplication of the similarity matrix to the image vector reduces image noise. The similarity matrices are calculated on both high- and low-energy CT images and averaged. In PWLS-SBR, the authors include a regularization term to minimize the L-2 norm of the difference between the images without and with noise suppression via similarity matrix multiplication. By using all pixel information of the initial CT images rather than just those lying on or near edges, PWLS-SBR is superior to the previously developed PWLS-EPR, as supported by comparison studies on phantoms and a head-and-neck patient. Results: On the line-pair slice of the Catphan{sup ©}600 phantom, PWLS-SBR outperforms PWLS-EPR and retains spatial resolution of 8 lp/cm, comparable to the original CT images, even at 90% reduction in noise standard deviation (STD). Similar performance on spatial resolution is observed on an anthropomorphic head phantom. In addition, results of PWLS-SBR show substantially improved image quality due to preservation of image NPS. On the Catphan{sup ©}600 phantom, NPS using PWLS-SBR has a correlation of 93% with that via direct matrix inversion, while the correlation drops to −52% for PWLS-EPR. Electron density measurement studies indicate high accuracy of PWLS-SBR. On seven different materials, the measured electron densities calculated from the decomposed material images using PWLS-SBR have a root-mean-square error (RMSE) of 1.20%, while the results of PWLS-EPR have a RMSE of 2.21%. In the study on a head-and-neck patient, PWLS-SBR is shown to reduce noise STD by a factor of 3 on material images with image qualities comparable to CT images, whereas fine structures are lost in the PWLS-EPR result. Additionally, PWLS-SBR better preserves low contrast on the tissue image. Conclusions: The authors propose improvements to the regularization term of an optimization framework which performs iterative image-domain decomposition for DECT with noise suppression. The regularization term avoids calculation of image gradient and is based on pixel similarity. The proposed method not only achieves a high decomposition accuracy, but also improves over the previous algorithm on NPS as well as spatial resolution.« less

Noise suppression for dual-energy CT via penalized weighted least-square optimization with similarity-based regularization

PubMed Central

Harms, Joseph; Wang, Tonghe; Petrongolo, Michael; Niu, Tianye; Zhu, Lei

2016-01-01

Purpose: Dual-energy CT (DECT) expands applications of CT imaging in its capability to decompose CT images into material images. However, decomposition via direct matrix inversion leads to large noise amplification and limits quantitative use of DECT. Their group has previously developed a noise suppression algorithm via penalized weighted least-square optimization with edge-preservation regularization (PWLS-EPR). In this paper, the authors improve method performance using the same framework of penalized weighted least-square optimization but with similarity-based regularization (PWLS-SBR), which substantially enhances the quality of decomposed images by retaining a more uniform noise power spectrum (NPS). Methods: The design of PWLS-SBR is based on the fact that averaging pixels of similar materials gives a low-noise image. For each pixel, the authors calculate the similarity to other pixels in its neighborhood by comparing CT values. Using an empirical Gaussian model, the authors assign high/low similarity value to one neighboring pixel if its CT value is close/far to the CT value of the pixel of interest. These similarity values are organized in matrix form, such that multiplication of the similarity matrix to the image vector reduces image noise. The similarity matrices are calculated on both high- and low-energy CT images and averaged. In PWLS-SBR, the authors include a regularization term to minimize the L-2 norm of the difference between the images without and with noise suppression via similarity matrix multiplication. By using all pixel information of the initial CT images rather than just those lying on or near edges, PWLS-SBR is superior to the previously developed PWLS-EPR, as supported by comparison studies on phantoms and a head-and-neck patient. Results: On the line-pair slice of the Catphan©600 phantom, PWLS-SBR outperforms PWLS-EPR and retains spatial resolution of 8 lp/cm, comparable to the original CT images, even at 90% reduction in noise standard deviation (STD). Similar performance on spatial resolution is observed on an anthropomorphic head phantom. In addition, results of PWLS-SBR show substantially improved image quality due to preservation of image NPS. On the Catphan©600 phantom, NPS using PWLS-SBR has a correlation of 93% with that via direct matrix inversion, while the correlation drops to −52% for PWLS-EPR. Electron density measurement studies indicate high accuracy of PWLS-SBR. On seven different materials, the measured electron densities calculated from the decomposed material images using PWLS-SBR have a root-mean-square error (RMSE) of 1.20%, while the results of PWLS-EPR have a RMSE of 2.21%. In the study on a head-and-neck patient, PWLS-SBR is shown to reduce noise STD by a factor of 3 on material images with image qualities comparable to CT images, whereas fine structures are lost in the PWLS-EPR result. Additionally, PWLS-SBR better preserves low contrast on the tissue image. Conclusions: The authors propose improvements to the regularization term of an optimization framework which performs iterative image-domain decomposition for DECT with noise suppression. The regularization term avoids calculation of image gradient and is based on pixel similarity. The proposed method not only achieves a high decomposition accuracy, but also improves over the previous algorithm on NPS as well as spatial resolution. PMID:27147376

Evaluation of Parkinson's disease by neuromelanin-sensitive magnetic resonance imaging and 123I-FP-CIT SPECT.

PubMed

Kuya, Keita; Ogawa, Toshihide; Shinohara, Yuki; Ishibashi, Mana; Fujii, Shinya; Mukuda, Naoko; Tanabe, Yoshio

2018-05-01

Background Both neuromelanin-sensitive magnetic resonance imaging (NmMRI) and 123 I-FP-CIT single photon emission computed tomography (SPECT) (DaTSCAN) assist the diagnosis of Parkinson's disease (PD). However, there have been few studies investigating a correlation between them. Purpose To correlate the utility of NmMRI and DaTSCAN and to evaluate the relationship between both imaging findings and the Unified PD rating scale part III (UPDRS III) score for the diagnosis and management of PD. Material and Methods Seventeen patients with PD who underwent both NmMRI and DaTSCAN were included. We measured the volume of the neuromelanin-positive substantia nigra pars compacta (SNc volume) on NmMRI and measured the specific binding ratio (SBR) on DaTSCAN. The asymmetry index (AI) of the SNc volume and SBR were also calculated. We evaluated the relationship between the UPDRS III score and the SNc volume and SBR, respectively. Results The SNc volume showed a significant correlation with the SBR. The AIs of them also showed a significant correlation. Both the mean of the bilateral SBR and the mean of the bilateral SNc volume showed significant negative correlations with the UPDRS III score. However, the correlation between the SBR and the UPDRS III score was stronger than that between the SNc volume and the UPDRS III score. Conclusion Both NmMRI and DaTSCAN are helpful for PD diagnosis. However, we conclude that DaTSCAN is more suitable for the evaluation of the clinical motor severity and would be more useful for the management of PD patients than NmMRI.

A Longitudinal Investigation of the Home Literacy Environment and Shared Book Reading in Young Children With Hearing Loss.

PubMed

DesJardin, Jean L; Stika, Carren J; Eisenberg, Laurie S; Johnson, Karen C; Hammes Ganguly, Dianne M; Henning, Shirley C; Colson, Bethany G

The principle goal of this longitudinal study was to examine parent perceptions of home literacy environment (e.g., frequency of book reading, ease of book reading with child) and observed behaviors during shared book reading (SBR) interactions between parents and their children with hearing loss (HL) as compared with parents and their children with normal hearing (NH) across 3 time points (12, 24, and 36 months old). Relationships were also explored among home literacy environment factors and SBR behaviors and later language outcomes, across all three time points for parents of children with and without HL. Participants were a group of parents and their children with HL (N = 17) and typically developing children with NH (N = 34). Parent perceptions about the home literacy environment were captured through a questionnaire. Observed parent behaviors and their use of facilitative language techniques were coded during videotaped SBR interactions. Children's oral language skills were assessed using a standardized language measure at each time point. No significant differences emerged between groups of parents (HL and NH) in terms of perceived home literacy environment at 12 and 36 months. However, significant group differences were evident for parent perceived ease of reading to their child at 24 months. Group differences also emerged for parental SBR behaviors for literacy strategies and interactive reading at 12 months and for engagement and interactive reading at 36 months, with parents of children with HL scoring lower in all factors. No significant relationships emerged between early home literacy factors and SBR behaviors at 12 months and oral language skills at 36 months for parents of children with NH. However, significant positive relationships were evident between early home literacy environment factors at 12 months and oral language skills at 36 months for parents and their children with HL. Although both groups of parents increased their frequency of SBR behaviors over time, parents of children with HL may need additional support to optimize SBR experiences to better guide their toddlers' and preschoolers' language skills. Early intervention efforts that focus on SBR interactions that are mutually enjoyed and incorporate specific ways to encourage parent-child conversations will be essential as children with HL acquire language.

Novel duplex vapor-electrochemical method for silicon solar cells

NASA Technical Reports Server (NTRS)

Kapur, V. K.; Nanis, L.; Sanjurjo, A.

1977-01-01

Silicon obtained by the SiF4-Na reaction was analyzed by spark source mass spectrometry (SSMS). Silicon samples prepared from induction melted powder were evaluated for electrical properties using four point probe conductivity and thermoelectric methods. SiF4-Na reaction under P sub SiF4 greater than 1 atmosphere. The amount of silicon produced was increased from 25 g per batch (in the glass reactor) to greater than 70 g per batch in the stainless steel reactor. The study of the effects of reaction variables such as P sub SiF4 and maximum temperature attained on the particle size of silicon powder showed that the silicon particle size tends to grow larger with increasing pressure of the SiF4 gas in the reaction system.

Low-temperature pre-treatments in a vertical epitaxial reactor with an improved vacuum load-lock chamber

NASA Astrophysics Data System (ADS)

Wang, Jie; Inokuchi, Yasuhiro; Kunii, Yasuo

2007-01-01

Low-temperature (<750 °C) surface preparation for epitaxial growth poses extra challenges for both hardware of a vertical batch epitaxial reactor and chemistry of in situ pre-epi treatments. The vacuum load-lock chamber of the vertical batch tool has been improved to ensure that residual moisture and oxygen concentrations are suppressed to less than 0.1 ppm. Si-based and Cl-based gases or a mixture of these gases are investigated in terms of effectiveness to remove interfacial residual oxygen at low temperatures (<750 °C). Under an optimized process condition, we found that interfacial oxygen can be reduced to less than 1 × 1012 cm-2 levels by low-temperature treatment with a mixture of Si-based and Cl-based gases.

Nitrile bioconversion by Microbacterium imperiale CBS 498-74 resting cells in batch and ultrafiltration membrane bioreactors.

PubMed

Cantarella, M; Cantarella, L; Gallifuoco, A; Spera, A

2006-03-01

The biohydration of acrylonitrile, propionitrile and benzonitrile catalysed by the NHase activity contained in resting cells of Microbacterium imperiale CBS 498-74 was operated at 5, 10 and 20 degrees C in laboratory-scale batch and membrane bioreactors. The bioreactions were conducted in buffered medium (50 mM Na(2)HPO(4)/NaH(2)PO(4), pH 7.0) in the presence of distilled water or tap-water, to simulate a possible end-pipe biotreatment process. The integral bioreactor performances were studied with a cell loading (dry cell weight; DCW) varying from 0.1 mg(DCW) per reactor to 16 mg(DCW) per reactor, in order to realize near 100% bioconversion of acrylonitrile, propionitrile and benzonitrile without consistent loss of NHase activity.

In Situ Monitoring of Ni-based Catalysts during the Synthesis of Propylene Carbonate

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

Ramin, Michael; Reimann, Sven; Grunwaldt, Jan-Dierk

2007-02-02

Three different nickel complexes were catalytically tested in the synthesis of propylene carbonate by carbon dioxide insertion. XAS measurements of the as prepared catalysts confirmed the differences in the structure which led to the varying catalytic activity. The structure of one of the active nickel-based catalysts was followed in situ by X-ray absorption spectroscopy using a specially designed batch reactor cell. The novel batch reactor allows in situ studies in dense carbon dioxide at elevated temperature and high pressure (up to 200 bar) even at the low energy of the nickel K-edge. Hence, important information on the fate of themore » ligands and structural changes under reaction conditions could be gained providing new insight into the reaction mechanism.« less

Evaluation of simultaneous organic matters and nutrients removal from municipal wastewater using a novel bioreactor (D-A2O) system.

PubMed

Ye, Changbing; Zhou, Zhiming; Li, Ming; Liu, Qin; Xu, Tiantian; Li, Jia

2018-07-15

A novel bioreactor, the divisional influent dual-anaerobic-anoxic/oxic (D-A 2 O) system, was applied to treat municipal wastewater. This new system improved the removal efficiency of simultaneous organic matters and nutrients, and provided a reduction in the system's energy costs and sludge yield. Results from the reactor's 18 months of operation demonstrated the following optimal conditions for the 4 key parameters of the system: (1) a divisional ratio (DR) of 8:2 between the influent flow volumes fed into the anaerobic and anoxic tanks, (2) a hydraulic retention time (HRT) of 6 h, (3) a R:r ratio of 200%:100% between the mixed liquor return ratio (R) and the return activated sludge ratio (r), and (4) an alternative operating time (t A/B ) of 1 h for the A/B anaerobic-anoxia series. Under optimal conditions, the system showed a high removal efficiency for the chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH 3 -N), and total phosphorus (TP) removals, with the average removal efficiencies (with a standard deviation of less than 3%) being 95.23%, 80.64%, 90.42%, and 90.03%, respectively. The final concentration ranges of COD, TN, NH 3 -N, and TP in the effluent were 26-48 mg L -1 , 6.11-11.03 mg L -1 , 2.93-4.04 mg L -1 , and 0.21-0.45 mg L -1 , respectively. The concentrations of the pollutants in the effluent from the D-A 2 O system were lower than those required for Level 1A (Chinese quality of wastewater discharge standard GB18918-2002). According to the results, we concluded that the divisional influent dual-anaerobic-anoxic system (which integrated the A 2 O and sequencing batch reactor (SBR) process) was successfully provided sufficient carbon sources for denitrification and phosphorus uptake without external carbon addition. Compared to the conventional anaerobic-anoxic/oxic (A 2 O) process, the D-A 2 O system offers a high removal efficiency, simple operation, and significant energy saving of about 0.276 kWh m -3 based on the volume of the treated water. Therefore, the new D-A 2 O system has a strong potential for use in treatment plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Source identification of nitrous oxide emission pathways from a single-stage nitritation-anammox granular reactor.

PubMed

Ali, Muhammad; Rathnayake, Rathnayake M L D; Zhang, Lei; Ishii, Satoshi; Kindaichi, Tomonori; Satoh, Hisashi; Toyoda, Sakae; Yoshida, Naohiro; Okabe, Satoshi

2016-10-01

Nitrous oxide (N2O) production pathway in a signal-stage nitritation-anammox sequencing batch reactor (SBR) was investigated based on a multilateral approach including real-time N2O monitoring, N2O isotopic composition analysis, and in-situ analyses of spatial distribution of N2O production rate and microbial populations in granular biomass. N2O emission rate was high in the initial phase of the operation cycle and gradually decreased with decreasing NH4(+) concentration. The average emission of N2O was 0.98 ± 0.42% and 1.35 ± 0.72% of the incoming nitrogen load and removed nitrogen, respectively. The N2O isotopic composition analysis revealed that N2O was produced via NH2OH oxidation and NO2(-) reduction pathways equally, although there is an unknown influence from N2O reduction and/or anammox N2O production. However, the N2O isotopomer analysis could not discriminate the relative contribution of nitrifier denitrification and heterotrophic denitrification in the NO2(-) reduction pathway. Various in-situ techniques (e.g. microsensor measurements and FISH (fluorescent in-situ hybridization) analysis) were therefore applied to further identify N2O producers. Microsensor measurements revealed that approximately 70% of N2O was produced in the oxic surface zone, where nitrifiers were predominantly localized. Thus, NH2OH oxidation and NO2 reduction by nitrifiers (nitrifier-denitrification) could be responsible for the N2O production in the oxic zone. The rest of N2O (ca. 30%) was produced in the anammox bacteria-dominated anoxic zone, probably suggesting that NO2(-) reduction by coexisting putative heterotrophic denitrifiers and some other unknown pathway(s) including the possibility of anammox process account for the anaerobic N2O production. Further study is required to identify the anaerobic N2O production pathways. Our multilateral approach can be useful to quantitatively examine the relative contributions of N2O production pathways. Good understanding of the key N2O production pathways is essential to establish a strategy to mitigate N2O emission from biological nitrogen removal processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ferrous Iron Oxidation by Thiobacillus ferrooxidans: Inhibition with Benzoic Acid, Sorbic Acid, and Sodium Lauryl Sulfate

PubMed Central

Onysko, Steven J.; Kleinmann, Robert L. P.; Erickson, Patricia M.

1984-01-01

Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds. PMID:16346592

Anaerobic sequencing batch reactor in pilot scale for treatment of tofu industry wastewater

NASA Astrophysics Data System (ADS)

Rahayu, Suparni Setyowati; Purwanto, Budiyono

2015-12-01

The small industry of tofu production process releases the waste water without being processed first, and the wastewater is directly discharged into water. In this study, Anaerobic Sequencing Batch Reactor in Pilot Scale for Treatment of Tofu Industry was developed through an anaerobic process to produce biogas as one kind of environmentally friendly renewable energy which can be developed into the countryside. The purpose of this study was to examine the fundamental characteristics of organic matter elimination of industrial wastewater with small tofu effective method and utilize anaerobic active sludge with Anaerobic Sequencing Bath Reactor (ASBR) to get rural biogas as an energy source. The first factor is the amount of the active sludge concentration which functions as the decomposers of organic matter and controlling selectivity allowance to degrade organic matter. The second factor is that HRT is the average period required substrate to react with the bacteria in the Anaerobic Sequencing Bath Reactor (ASBR).The results of processing the waste of tofu production industry using ASBR reactor with active sludge additions as starter generates cumulative volume of 5814.4 mL at HRT 5 days so that in this study it is obtained the conversion 0.16 L of CH4/g COD and produce biogas containing of CH4: 81.23% and CO2: 16.12%. The wastewater treatment of tofu production using ASBR reactor is able to produce renewable energy that has economic value as well as environmentally friendly by nature.

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

Vargas, Ronald; Nunez, Oswaldo

Photodegradation/mineralization (TiO{sub 2}/UV Light) of the hydrocarbons: p-nitrophenol (PNP), naphthalene (NP) and dibenzothiophene (DBT) at three different reactors: batch bench reactor (BBR), tubular bench reactor (TBR) and tubular pilot-plant (TPP) were kinetically monitored at pH = 3, 6 and 10, and the results compared using normalized UV light exposition times. The results fit the Langmuir-Hinshelwood (LH) model; therefore, LH adsorption equilibrium constants (K) and apparent rate constants (k) are reported as well as the apparent pseudo-first-order rate constants, k{sub obs}{sup '} = kK/(1 + Kc{sub r}). The batch bench reactor is the most selective reactor toward compound and pH changesmore » in which the reactivity order is: NP > DBT > PNP, however, the catalyst adsorption (K) order is: DBT > NP > PNP at the three pH used but NP has the highest k values. The tubular pilot-plant (TPP) is the most efficient of the three reactors tested. Compound and pH photodegradation/mineralization selectivity is partially lost at the pilot plant where DBT and NP reaches ca. 90% mineralization at the pH used, meanwhile, PNP reaches only 40%. The real time, in which these mineralization occur are: 180 min for PNP and 60 min for NP and DBT. The mineralization results at the TPP indicate that for the three compounds, the rate limiting step is the same as the degradation one. So that, there is not any stable intermediate that may accumulate during the photocatalytic treatment. (author)« less

A direct comparison of U.S. Environmental Protection Agency's method 304B and batch tests for determining activated-sludge biodegradation rate constants for volatile organic compounds

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

Cano, M.L.; Wilcox, M.E.; Compernolle, R. van

Biodegradation rate constants for volatile organic compounds (VOCs) in activated-sludge systems are needed to quantify emissions. One current US environmental Protection Agency method for determining a biodegradation rate constant is Method 304B. In this approach, a specific activated-sludge unit is simulated by a continuous biological treatment system with a sealed headspace. Batch experiments, however, can be alternatives to Method 304B. Two of these batch methods are the batch test that uses oxygen addition (BOX) and the serum bottle test (SBT). In this study, Method 304B was directly compared to BOX and SBT experiments. A pilot-scale laboratory reactor was constructed tomore » serve as the Method 304B unit. Biomass from the unit was also used to conduct BOX and modified SBT experiments (modification involved use of a sealed draft-tube reactor with a headspace recirculation pump instead of a serum bottle) for 1,2-dichloroethane, diisopropyl ether, methyl tertiary butyl ether, and toluene. Three experimental runs--each consisting of one Method 304B experiment, one BOX experiment, and one modified SBT experiment--were completed. The BOX and SBT data for each run were analyzed using a Monod model, and best-fit biodegradation kinetic parameters were determined for each experiment, including a first-order biodegradation rate constant (K{sub 1}). Experimental results suggest that for readily biodegradable VOCs the two batch techniques can provide improved means of determining biodegradation rate constants compared with Method 304B. In particular, these batch techniques avoid the Method 304B problem associated with steady-state effluent concentrations below analytical detection limits. However, experimental results also suggest that the two batch techniques should not be used to determine biodegradation rate constants for slowly degraded VOCs (i.e., K{sub 1} {lt} 0.1 L/g VSS-h).« less

[Development of a near-infrared fluorescence imaging system based on fluorescence properties of methylene blue].

PubMed

Huang, Lu-Mao; DU, Pei-Yan; Chen, Lan; Zhang, Sa; Zhou, Di-Fu; Chen, Chun-Lin; Xin, Xue-Gang

2018-04-20

To develop a near-infrared fluorescence imaging system based on the fluorescence properties of methylene blue. According to the optical properties of methylene blue, we used a custom-made specific LED light source and an interference filter, a CCD camera and other relevant components to construct the near-infrared fluorescence imaging system. We tested the signal-to-background ratio (SBR) of this imaging system for detecting methylene blue under different experimental conditions and analyzed the SBR in urine samples collected from 15 Wistar rats with intravenous injection of methylene blue at the doses of 0, 1.4, 1.6, 1.8, or 2.0 0 mg/kg methylene blue. The SBR of this imaging system for detecting methylene blue was affected by the concentration of methylene blue and the distance from the sample (P<0.05). In the urine samples from Wistar rats, the SBR varied with the the injection dose, and the rats injected with 1.6 mg/kg methylene blue showed the highest SBR (8.71∓0.20) in the urine (P<0.05). This near-infrared fluorescence imaging system is useful for fluorescence detection of methylene blue and can be used for real-time recognition of ureters during abdominal surgery.

Water requirements of the styrene, butadiene and synthetic-rubber industries

USGS Publications Warehouse

Durfor, Charles N.

1963-01-01

About 710 million gallons of makeup water is withdrawn daily by the styrene, butadiene, styrene-butadiene rubber (SBR), and specialty-rubber industries; 88 percent of this water is used only for once-through cooling. About 429 million gallons of water daily (mgd) is withdrawn by the butadiene industry; 158 ragd is withdrawn by the styrene industry; 94 mgd is used to make special-purpose synthetic rubber; and 29 mgd is used in the direct manufacture of SBR. The amount of makeup water withdrawn to produce SBR ranges from 11,400 to 418,000 gallons per long ton of finished rubber. The amount of makeup water withdrawn depends upon the type of rubber, the processes used to make SBR and its intermediates (styrene and butadiene), and the availability of water at the styrene, butadiene, and SBR plants. The amount of makeup water used to make styrene ranged from 2.19 to 123 gallons per pound; to make butadiene, ranged from 5.38 to 22.0 gallons per pound; and in the direct manufacture of SBR, ranged from 0.883 to 10.2 gallons per pound of finished rubber. The amount of makeup water withdrawn for use in the manufacture of special-purpose synthetic rubber ranged from 8.45 to 104 gallons per pound. About 64 percent of the makeup water was obtained from salty water sources. These waters, which were used only in once-through cooling, contained as much as 35,000 ppm of dissolved solids. About 26 percent of the makeup water was obtained from fresh-water streams and lakes, and most of the other makeup waters were obtained from ground water. Less than 1 percent of the makeup water was obtained from reprocessed municipal sewage. Most makeup water from fresh-water streams, lakes, and wells contained less than 1,000 ppm of dissolved solids, and most makeup water used in the manufacture of SBR contained less than 500 ppm of dissolved solids. The maximum hardness of the untreated fresh makeup waters; used in the manufacture of SBR was less than 500 ppm. About 97 percent of the makeup water withdrawn was discharged to surface waters; the warmed salty waters were returned to their source. The remaining 3 percent, or about 23.6 mgd, of makeup water was used consumptively. The styrene industry consumptively used about 2.0 percent of its intake; the butadiene industry, about 4.5 percent; the specialty-rubber industry, about 9.1 percent; and the SBR industry, about 11 percent. The water shipped in the synthetic-rubber products increased the consumptive use of water by these industries.

Gravimetric enrichment of high lipid and starch accumulating microalgae.

PubMed

Hassanpour, Morteza; Abbasabadi, Mahsa; Ebrahimi, Sirous; Hosseini, Maryam; Sheikhbaglou, Ahmad

2015-11-01

This study presents gravimetric enrichment of mixed culture to screen starch and lipid producing species separately in a sequencing batch reactor. In the enriched starch-producing mixed culture photobioreactor, the starch content at the end of steady state batch became 3.42 times the beginning of depletion. Whereas in the enriched lipid-producing photobioreactor, the lipid content at the end of steady state batch became 3 times the beginning of famine phase. The obtained results revealed that the gravimetric enrichment is a suitable screening method for specific production of storage compounds in none-sterile large-scaled condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Statistical study of EBR-II fuel elements manufactured by the cold line at Argonne-West and by Atomics International

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

Harkness, A. L.

1977-09-01

Nine elements from each batch of fuel elements manufactured for the EBR-II reactor have been analyzed for /sup 235/U content by NDA methods. These values, together with those of the manufacturer, are used to estimate the product variance and the variances of the two measuring methods. These variances are compared with the variances computed from the stipulations of the contract. A method is derived for resolving the several variances into their within-batch and between-batch components. Some of these variance components have also been estimated by independent and more familiar conventional methods for comparison.

Comparison of different liquid anaerobic digestion effluents as inocula and nitrogen sources for solid-state batch anaerobic digestion of corn stover

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

Xu Fuqing; Shi Jian; Lv Wen

2013-01-15

Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch anaerobic digestion of cornmore » stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairy waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch anaerobic digestion reactors was closely related to the microbial status in the liquid anaerobic digestion effluents.« less

Novel Anaerobic Wastewater Treatment System for Energy Generation at Forward Operating Bases

DTIC Science & Technology

2016-08-01

AnMBR) technology with clinoptilolite ion exchange and GreenBox™ ammonia electrolysis. The system generates both methane and hydrogen fuels...experimental setup. ................................................ 21 Figure 10. Methane phase semi batch experimental setup, a total of three reactors were...set up for PS + solid, Bioc and ADS methane phase reactors. .................... 21 Figure 11. Dried PS solid for the control, Bioc blend for the

Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

PubMed

Batstone, D J; Torrijos, M; Ruiz, C; Schmidt, J E

2004-01-01

The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter estimation, especially for comparative wastewater characterisation. The main disadvantages are heavy computational requirements for multiple cycles, and difficulty in establishing the correct biomass concentration in the reactor, though the last is also a disadvantage for continuous fixed film reactors, and especially, batch tests.

New approach to the ecotoxicological risk assessment of artificial outdoor sporting grounds.

PubMed

Krüger, O; Kalbe, U; Richter, E; Egeler, P; Römbke, J; Berger, W

2013-04-01

Artificial surfaces for outdoor sporting grounds may pose environmental and health hazards that are difficult to assess due to their complex chemical composition. Ecotoxicity tests can indicate general hazardous impacts. We conducted growth inhibition (Pseudokirchneriella subcapitata) and acute toxicity tests (Daphnia magna) with leachates obtained from batch tests of granular infill material and column tests of complete sporting ground assemblies. Ethylene propylene diene monomer rubber (EPDM) leachate showed the highest effect on Daphnia magna (EC(50) < 0.4% leachate) and the leachate of scrap tires made of styrene butadiene rubber (SBR) had the highest effect on P. subcapitata (EC(10) = 4.2% leachate; EC(50) = 15.6% leachate). We found no correlations between ecotoxicity potential of leachates and zinc and PAH concentrations. Leachates obtained from column tests revealed lower ecotoxicological potential. Leachates of column tests of complete assemblies may be used for a reliable risk assessment of artificial sporting grounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Chemical vapor deposition of epitaxial silicon

DOEpatents

Berkman, Samuel

1984-01-01

A single chamber continuous chemical vapor deposition (CVD) reactor is described for depositing continuously on flat substrates, for example, epitaxial layers of semiconductor materials. The single chamber reactor is formed into three separate zones by baffles or tubes carrying chemical source material and a carrier gas in one gas stream and hydrogen gas in the other stream without interaction while the wafers are heated to deposition temperature. Diffusion of the two gas streams on heated wafers effects the epitaxial deposition in the intermediate zone and the wafers are cooled in the final zone by coolant gases. A CVD reactor for batch processing is also described embodying the deposition principles of the continuous reactor.

Effect of Different Binders on the Electrochemical Performance of Metal Oxide Anode for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Wang, Rui; Feng, Lili; Yang, Wenrong; Zhang, Yinyin; Zhang, Yanli; Bai, Wei; Liu, Bo; Zhang, Wei; Chuan, Yongming; Zheng, Ziguang; Guan, Hongjin

2017-10-01

When testing the electrochemical performance of metal oxide anode for lithium-ion batteries (LIBs), binder played important role on the electrochemical performance. Which binder was more suitable for preparing transition metal oxides anodes of LIBs has not been systematically researched. Herein, five different binders such as polyvinylidene fluoride (PVDF) HSV900, PVDF 301F, PVDF Solvay5130, the mixture of styrene butadiene rubber and sodium carboxymethyl cellulose (SBR+CMC), and polyacrylonitrile (LA133) were studied to make anode electrodes (compared to the full battery). The electrochemical tests show that using SBR+CMC and LA133 binder which use water as solution were significantly better than PVDF. The SBR+CMC binder remarkably improve the bonding capacity, cycle stability, and rate performance of battery anode, and the capacity retention was about 87% after 50th cycle relative to the second cycle. SBR+CMC binder was more suitable for making transition metal oxides anodes of LIBs.