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Sample records for anaerobic membrane bioreactors

  1. Applicability of dynamic membrane technology in anaerobic membrane bioreactors.

    PubMed

    Ersahin, Mustafa Evren; Ozgun, Hale; Tao, Yu; van Lier, Jules B

    2014-01-01

    This study investigated the applicability of dynamic membrane technology in anaerobic membrane bioreactors for the treatment of high strength wastewaters. A monofilament woven fabric was used as support material for dynamic membrane formation. An anaerobic dynamic membrane bioreactor (AnDMBR) was operated under a variety of operational conditions, including different sludge retention times (SRTs) of 20 and 40 days in order to determine the effect of SRT on both biological performance and dynamic membrane filtration characteristics. High COD removal efficiencies exceeding 99% were achieved during the operation at both SRTs. Higher filtration resistances were measured during the operation at SRT of 40 days in comparison to SRT of 20 days, applying a stable flux of 2.6 L/m(2) h. The higher filtration resistances coincided with lower extracellular polymeric substances concentration in the bulk sludge at SRT of 40 days, likely resulting in a decreased particle flocculation. Results showed that dynamic membrane technology achieved a stable and high quality permeate and AnDMBRs can be used as a reliable and satisfactory technology for treatment of high strength wastewaters.

  2. Performance of an anaerobic membrane bioreactor for pharmaceutical wastewater treatment.

    PubMed

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

    2017-04-01

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

  3. Characterization of organic membrane foulants in a forward osmosis membrane bioreactor treating anaerobic membrane bioreactor effluent.

    PubMed

    Ding, Yi; Tian, Yu; Li, Zhipeng; Liu, Feng; You, Hong

    2014-09-01

    In this study, two aerobic forward osmosis (FO) membrane bioreactors (MBR) were utilized to treat the effluent of mesophilic (35°C) and atmospheric (25°C) anaerobic MBRs, respectively. The results showed that the FO membrane process could significantly improve the removal efficiencies of N and P. Meanwhile, the flux decline of the FOMBR treating effluent of mesophilic AnMBR (M-FOMBR) was higher than that treating effluent of atmospheric AnMBR (P-FOMBR). The organic membrane foulants in the two FOMBRs were analyzed to understand the membrane fouling behavior in FO processes. It was found that the slightly increased accumulation of protein-like substances into external foulants did not cause faster flux decline in P-FOMBR than that in M-FOMBR. However, the quantity of organic matter tended to deposit or adsorb into FO membrane pores in P-FOMBR was less than that in M-FOMBR, which was accordance with the tendency of membrane fouling indicated by flux decline.

  4. Development of a high-rate submerged anaerobic membrane bioreactor.

    PubMed

    Mahmoud, I; Gao, W J; Liao, B Q; Cumin, J; Dagnew, M; Hong, Y

    2017-04-04

    Typically, anaerobic membrane bioreactors are operated at an organic loading rate (OLR) less than 10 kg chemical oxygen demand (COD)/m(3 )d. This paper discusses the development and performance of a high-rate submerged anaerobic membrane bioreactor (SAnMBR) for a high-strength synthetic industrial wastewater treatment. An OLR as high as 41 kg COD/m(3) d was achieved with excellent COD removal efficiency (>99%). The membrane was operated at constant fluxes (9.4-9.9 ± 0.5 L/m(2) h) and the change in trans-membrane pressure (TMP) was monitored to characterize the membrane performance. The results showed a low TMP (<5 kPa) under steady-state operation with only biogas sparging and relaxation as control strategy for over 300 days, implying no significant fouling was developed. Inorganic fouling was the dominant fouling mechanism occurred at the end of the study. The results suggest that the newly developed SAnMBR configuration can treat high-strength wastewater at lower capital expenditure while still providing superior effluent quality for water reuse or system closure.

  5. Instrumentation, control, and automation for submerged anaerobic membrane bioreactors.

    PubMed

    Robles, Ángel; Durán, Freddy; Ruano, María Victoria; Ribes, Josep; Rosado, Alfredo; Seco, Aurora; Ferrer, José

    2015-01-01

    A submerged anaerobic membrane bioreactor (AnMBR) demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON®, Koch Membrane Systems, PUR-PSH31) was designed and operated for urban wastewater treatment. An instrumentation, control, and automation (ICA) system was designed and implemented for proper process performance. Several single-input-single-output (SISO) feedback control loops based on conventional on-off and PID algorithms were implemented to control the following operating variables: flow-rates (influent, permeate, sludge recycling and wasting, and recycled biogas through both reactor and membrane tanks), sludge wasting volume, temperature, transmembrane pressure, and gas sparging. The proposed ICA for AnMBRs for urban wastewater treatment enables the optimization of this new technology to be achieved with a high level of process robustness towards disturbances.

  6. Fermentative hydrogen production in anaerobic membrane bioreactors: A review.

    PubMed

    Bakonyi, P; Nemestóthy, N; Simon, V; Bélafi-Bakó, K

    2014-03-01

    Reactor design considerations are crucial aspects of dark fermentative hydrogen production. During the last decades, many types of reactors have been developed and used in order to drive biohydrogen technology towards practicality and economical-feasibility. In general, the ultimate aim is to improve the key features of the process, namely the H2 yields and generation rates. Among the various configurations, the traditional, completely stirred tank reactors (CSTRs) are still the most routinely employed ones. However, due to their limitations, there is a progress to develop more reliable alternatives. One of the research directions points to systems combining membranes, which are called as anaerobic membrane bioreactors (AnMBRs). The aim of this paper is to summarize and highlight the recent biohydrogen related work done on AnMBRs and moreover to evaluate their performances and potentials in comparison with their conventional CSTR counterparts.

  7. Modelling wastewater treatment in a submerged anaerobic membrane bioreactor.

    PubMed

    Spagni, Alessandro; Ferraris, Marco; Casu, Stefania

    2015-01-01

    Mathematical modelling has been widely applied to membrane bioreactor (MBRs) processes. However, to date, very few studies have reported on the application of the anaerobic digestion model N.1 (ADM1) to anaerobic membrane processes. The aim of this study was to evaluate the applicability of the ADM1 to a submerged anaerobic MBR (SAMBR) treating simulated industrial wastewater composed of cheese whey and sucrose. This study demonstrated that the biological processes involved in SAMBRs can be modelled by using the ADM1. Moreover, the results showed that very few modifications of the parameters describing the ADM1 were required to reasonably fit the experimental data. In particular, adaptation to the specific conditions of the coefficients describing the wastewater characterisation and the reduction of the hydrolysis rate of particulate carbohydrate (khyd,ch) from 0.25 d(-1) (as suggested by the ADM1 for high-rate mesophilic reactors) to 0.13 d(-1) were required to fit the experimental data.

  8. Comparing the value of bioproducts from different stages of anaerobic membrane bioreactors.

    PubMed

    Khan, M A; Ngo, H H; Guo, W S; Liu, Y W; Zhou, J L; Zhang, J; Liang, S; Ni, B J; Zhang, X B; Wang, J

    2016-08-01

    The anaerobic digestion process in anaerobic membrane bioreactors is an effective way for waste management, energy sustainability and pollution control in the environment. This digestion process basically involves the production of volatile fatty acids and biohydrogen as intermediate products and methane as a final product. This paper compares the value of bioproducts from different stages of anaerobic membrane bioreactors through a thorough assessment. The value was assessed in terms of technical feasibility, economic assessment, environmental impact and impact on society. Even though the current research objective is more inclined to optimize the production of methane, the intermediate products could also be considered as economically attractive and environment friendly options. Hence, this is the first review study to correlate the idea into an anaerobic membrane bioreactor which is expected to guide future research pathways regarding anaerobic process and its bioproducts.

  9. Membrane fouling control using a rotary disk in a submerged anaerobic membrane sponge bioreactor.

    PubMed

    Kim, Jungmin; Shin, Jaewon; Kim, Hyemin; Lee, Jung-Yeol; Yoon, Min-Hyuk; Won, Seyeon; Lee, Byung-Chan; Song, Kyung Guen

    2014-11-01

    Despite significant research efforts over the last few decades, membrane fouling in anaerobic membrane bioreactors (AnMBRs) remains an unsolved problem that increases the overall operational costs and obstructs the industrial applications. Herein, we developed a method for effectively controlling the membrane fouling in a sponge-submerged AnMBRs using an anaerobic rotary disk MBR (ARMBR). The disk rotation led the effective collision between the sponge and membrane surface; thus successfully enhanced the membrane permeability in the ARMBR. The effect of the disk rotational speed and sponge volume fraction on the membrane permeability and the relationship between the water flow direction and membrane permeability were investigated. The long-term feasibility was tested over 100days of synthetic wastewater treatment. As a result, stable and economical performance was observed without membrane replacement and washing. The proposed integrated rotary disk-supporting media appears to be a feasible and even beneficial option in the AnMBR technology.

  10. Dynamic Membrane Formation in Anaerobic Dynamic Membrane Bioreactors: Role of Extracellular Polymeric Substances

    PubMed Central

    Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

    2015-01-01

    Dynamic membrane (DM) formation in dynamic membrane bioreactors plays an important role in achieving efficient solid-liquid separation. In order to study the contribution of extracellular polymeric substances (EPS) to DM formation in anaerobic dynamic membrane bioreactor (AnDMBR) processes, EPS extraction from and re-addition to bulk sludge were carried out in short-term filtration tests. DM formation behaviors could be well simulated by cake filtration model, and sludge with EPS re-addition showed the highest resistance coefficient, followed by sludge after EPS extraction. The DM layers exhibited a higher resistance and a lower porosity for the sludge sample after EPS extraction and for the sludge with EPS re-addition. Particle size of sludge flocs decreased after EPS extraction, and changed little with EPS re-addition, which was confirmed by interaction energy analysis. Further investigations by confocal laser scanning microscopy (CLSM) analysis and batch tests suggested that the removal of in-situ EPS stimulated release of soluble EPS, and re-added EPS were present as soluble EPS rather than bound EPS, which thus improved the formation of DM. The present work revealed the role of EPS in anaerobic DM formation, and could facilitate the operation of AnDMBR processes. PMID:26436551

  11. Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment

    PubMed Central

    Smith, Adam L; Skerlos, Steven J; Raskin, Lutgarde

    2015-01-01

    Membrane biofilm development was evaluated to improve psychrophilic (15°C) anaerobic membrane bioreactor (AnMBR) treatment of domestic wastewater. An AnMBR containing three replicate submerged membrane housings with separate permeate collection was operated at three levels of membrane fouling by independently controlling biogas sparging for each membrane unit. High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry’s law. Illumina sequencing of 16S rRNA targeting Bacteria and Archaea and reverse transcription-quantitative polymerase chain reaction targeting the methyl coenzyme-M reductase (mcrA) gene in methanogens indicated that the membrane biofilm was enriched in highly active methanogens and syntrophic bacteria. Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm’s treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP. Dissolved methane oversaturation persisted without high TMP, implying that methanogenesis in the biofilm, rather than high TMP, was the primary driving force in methane oversaturation. The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling. PMID:26238293

  12. Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment.

    PubMed

    Smith, Adam L; Skerlos, Steven J; Raskin, Lutgarde

    2015-09-01

    Membrane biofilm development was evaluated to improve psychrophilic (15°C) anaerobic membrane bioreactor (AnMBR) treatment of domestic wastewater. An AnMBR containing three replicate submerged membrane housings with separate permeate collection was operated at three levels of membrane fouling by independently controlling biogas sparging for each membrane unit. High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law. Illumina sequencing of 16S rRNA targeting Bacteria and Archaea and reverse transcription-quantitative polymerase chain reaction targeting the methyl coenzyme-M reductase (mcrA) gene in methanogens indicated that the membrane biofilm was enriched in highly active methanogens and syntrophic bacteria. Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP. Dissolved methane oversaturation persisted without high TMP, implying that methanogenesis in the biofilm, rather than high TMP, was the primary driving force in methane oversaturation. The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.

  13. Anaerobic treatment of municipal wastewater with a staged anaerobic fluidized membrane bioreactor (SAF-MBR) system.

    PubMed

    Yoo, Rihye; Kim, Jeonghwan; McCarty, Perry L; Bae, Jaeho

    2012-09-01

    A laboratory-scale staged anaerobic fluidized membrane bioreactor (SAF-MBR) system was used to treat a municipal wastewater primary-clarifier effluent. It was operated continuously for 192 days at 6-11 L/m(2)/h flux and trans-membrane pressure generally of 0.1 bar or less with no fouling control except the scouring effect of the fluidized granular activated carbon on membrane surfaces. With a total hydraulic retention time of 2.3h at 25°C, the average effluent chemical oxygen demand and biochemical oxygen demand concentrations of 25 and 7 mg/L yielded corresponding removals of 84% and 92%, respectively. Also, near complete removal of suspended solids was obtained. Biosolids production, representing 5% of the COD removed, equaled 0.049 g VSS/g BOD(5) removed, far less than the case with comparable aerobic processes. The electrical energy required for the operation of the SAF-MBR system, 0.047 kW h/m(3), could be more than satisfied by using the methane produced.

  14. Characteristics and role of dynamic membrane layer in anaerobic membrane bioreactors.

    PubMed

    Ersahin, Mustafa Evren; Tao, Yu; Ozgun, Hale; Spanjers, Henri; van Lier, Jules B

    2016-04-01

    A submerged anaerobic dynamic membrane bioreactor (AnDMBR) was operated for treatment of concentrated wastewater. The dynamic membrane (DM) or cake layer was characterized on its physicochemical and biological composition and the role of the DM layer in treatment and filtration performances was assessed. The results showed that the DM layer had an important role in organic matter removal. Both organic and inorganic materials, such as sludge particles, soluble microbial products (SMP), extracellular polymeric substances (EPS), and Ca, N, P, Mg precipitations contributed to the DM layer formation. Thus, effective retention of very small particles by the DM layer was achieved. The DM layer had higher microbial diversity and different microbial population composition in comparison to the bulk sludge. Overall, this study provided a better understanding about the DM layer structure in AnDMBRs, which might lead to increased applicability of this promising technology for the treatment of concentrated wastewaters.

  15. Navigating wastewater energy recovery strategies: a life cycle comparison of anaerobic membrane bioreactor and conventional treatment systems with anaerobic digestion.

    PubMed

    Smith, Adam L; Stadler, Lauren B; Cao, Ling; Love, Nancy G; Raskin, Lutgarde; Skerlos, Steven J

    2014-05-20

    The objective of this study was to evaluate emerging anaerobic membrane bioreactor (AnMBR) technology in comparison with conventional wastewater energy recovery technologies. Wastewater treatment process modeling and systems analyses were combined to evaluate the conditions under which AnMBR may produce more net energy and have lower life cycle environmental emissions than high rate activated sludge with anaerobic digestion (HRAS+AD), conventional activated sludge with anaerobic digestion (CAS+AD), and an aerobic membrane bioreactor with anaerobic digestion (AeMBR+AD). For medium strength domestic wastewater treatment under baseline assumptions at 15 °C, AnMBR recovered 49% more energy as biogas than HRAS+AD, the most energy positive conventional technology considered, but had significantly higher energy demands and environmental emissions. Global warming impacts associated with AnMBR were largely due to emissions of effluent dissolved methane. For high strength domestic wastewater treatment, AnMBR recovered 15% more net energy than HRAS+AD, and the environmental emissions gap between the two systems was reduced. Future developments of AnMBR technology in low energy fouling control, increased flux, and management of effluent methane emissions would make AnMBR competitive with HRAS+AD. Rapid advancements in AnMBR technology must continue to achieve its full economic and environmental potential as an energy recovery strategy for domestic wastewater.

  16. Organic micropollutants in aerobic and anaerobic membrane bioreactors: Changes in microbial communities and gene expression.

    PubMed

    Harb, Moustapha; Wei, Chun-Hai; Wang, Nan; Amy, Gary; Hong, Pei-Ying

    2016-10-01

    Organic micro-pollutants (OMPs) are contaminants of emerging concern in wastewater treatment due to the risk of their proliferation into the environment, but their impact on the biological treatment process is not well understood. The purpose of this study is to examine the effects of the presence of OMPs on the core microbial populations of wastewater treatment. Two nanofiltration-coupled membrane bioreactors (aerobic and anaerobic) were subjected to the same operating conditions while treating synthetic municipal wastewater spiked with OMPs. Microbial community dynamics, gene expression levels, and antibiotic resistance genes were analyzed using molecular-based approaches. Results showed that presence of OMPs in the wastewater feed had a clear effect on keystone bacterial populations in both the aerobic and anaerobic sludge while also significantly impacting biodegradation-associated gene expression levels. Finally, multiple antibiotic-type OMPs were found to have higher removal rates in the anaerobic MBR, while associated antibiotic resistance genes were lower.

  17. Impacts of different draw solutions on a novel anaerobic forward osmosis membrane bioreactor (AnFOMBR).

    PubMed

    Tang, Melvin Kai Yin; Ng, How Yong

    2014-01-01

    Two anaerobic forward osmosis (FO) membrane bioreactors (AnFOMBRs), Rchloride and Rsulfate, were operated for 100 days using NaCl and Na2SO4 as the draw solution, respectively. The operating conditions were identical for both systems, with a solids retention time of 30 d, hydraulic retention time of 8 h and using cellulose triacetate FO membrane. High rejection performance of FO membranes resulted in salinity accumulation in the bioreactors. Rchloride and Rsulfate reached a stable conductivity of about 35 and 11 mS/cm, respectively, at the end of the experimental run. Hypersalinity of Rchloride undesirably impacted biological growth; mixed liquor volatile suspended solids in Rchloride was much lower at 376 mg/L, whereas that of Rsulfate was 1,170 mg/L. Organic removals were excellent due to reduced organic loadings at low fluxes and thus, Rsulfate and Rchloride achieved secondary total organic carbon (TOC) removal efficiencies of at least 75%. Both AnFOMBRs started with an initial flux of 5 LMH. Flux for Rchloride stabilized at 0.25 LMH, while Rsulfate at 0.96 LMH. The high salinities of both reactors negatively impacted methanogenic growth. Application of the fluorescence in-situ hybridization (FISH) technique confirmed the ousting of methanogens by sulfate reducing bacteria from the anaerobic consortium. Sparsely located methanogens were detected in Rchloride but none were detected in Rsulfate.

  18. Effect of biogas sparging with different membrane modules on membrane fouling in anaerobic submerged membrane bioreactor (AnSMBR).

    PubMed

    Aslan, Mustafa; Saatçi, Yusuf; Hanay, Özge; Hasar, Halil

    2014-03-01

    This study focused on the effect of biogas sparging and different membrane modules such as cylinder shaped, funnel-shaped, and U-shaped on the membrane fouling behavior in a lab-scale submerged anaerobic membrane bioreactor (AnSMBR) which was operated for over 60 days. In order to investigate the membrane fouling behavior, a series of analysis such as SMP, EPS, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), particle size distribution, and filtration resistances were performed. Although the rapid generation of cake layer took placed in case of the absence of biogas sparging, the membrane module design mostly influenced the membrane resistance when biogas sparging was applied. Total resistance was the highest for U-shaped module. The permeate fluxes with biogas sparging were higher about one half and two times than those without biogas sparging. Cylinder-shaped module had the lowest SMP and EPS concentrations followed by U-shaped and funnel-shaped modules under both cases with and without biogas sparging. The total resistances of all membrane modules without biogas sparging were found to be very high compared the pore blocking resistances (Rp).

  19. Fouling cake layer in a submerged anaerobic membrane bioreactor treating saline wastewaters: curse or a blessing?

    PubMed

    Vyrides, I; Stuckey, D C

    2011-01-01

    The treatment of inhibitory (saline) wastewaters is known to produce considerable amounts of soluble microbial products (SMPs), and this has been implicated in membrane fouling; the fate of these SMPs was of considerable interest in this work. This study also investigated the contribution of SMPs to membrane fouling of the; (a) cake layer/biofilm layer, (b) the compounds below the biofilm/cake layer and strongly attached to the surface of the membrane, (c) the compounds in the inner pores of the membrane, and (d) the membrane. It was found that the cake/biofilm layer was the main reason for fouling of the membrane. Interestingly, the bacteria attached to the cake/biofilm layer showed higher biodegradation rates compared with the bacteria in suspension. Moreover, the bacteria attached to the cake layer showed higher amounts of attached extracellular polysaccharides (EPS) compared with the bacteria in suspension, possibly due to accumulation of the released EPS from suspended biomass in the cake/biofilm layer. Molecular weight (MW) analysis of the effluent and reactor bulk showed that the cake layer can retain a large fraction of the SMPs in the reactor and prevent them from being released into the effluent. Hence, while cake layers lead to lower fluxes in submerged anaerobic membrane bioreactors (SAMBRS), and hence higher costs, they can improve the quality of the reactor effluent.

  20. Comparison of the filtration characteristics of organic and inorganic membranes in a membrane-coupled anaerobic bioreactor.

    PubMed

    Kang, In-Joong; Yoon, Seong-Hoon; Lee, Chung-Hak

    2002-04-01

    Comparison of filtration characteristics of organic and inorganic membranes was made in terms of physicochemical properties of the membrane materials, cake layer formation, backflushing and backfeeding effects in a membrane-coupled anaerobic bioreactor. For the inorganic membrane, struvite (MgNH4PO4 x 6H2O) was found to have accumulated inside the membrane pore and plays a key role in flux decline. For the organic, however, a thick cake layer composed of biomass and struvite formed on the membrane surface, thus causing a major hydraulic resistance. In order to mitigate flux decline for both membranes, backflushing and backfeeding modes were examined. With acidic (pH 2.0) backflushing, the flux was approximately doubled for the organic membrane. However, unexpectedly a negative effect was observed for the inorganic membrane. An alkaline backflushing instead of acidic backflushing gave rise to a flux improvement by a factor of two without any negative effect, even for the inorganic membrane. The backfeeding mode gave rise to a much higher flux compared with the normal mode in both types of membrane, although the flux returned to the same level as that with the normal mode after 6 days for the inorganic membrane. The differences between the two types of membranes were explained by membrane morphology, a ligand exchange reaction as well as a surface charge effect.

  1. Effects of dissolved organic matters (DOMs) on membrane fouling in anaerobic ceramic membrane bioreactors (AnCMBRs) treating domestic wastewater.

    PubMed

    Yue, Xiaodi; Koh, Yoong Keat Kelvin; Ng, How Yong

    2015-12-01

    Anaerobic membrane bioreactors (AnMBRs) have been regarded as a potential solution to achieve energy neutrality in the future wastewater treatment plants. Coupling ceramic membranes into AnMBRs offers great potential as ceramic membranes are resistant to corrosive chemicals such as cleaning reagents and harsh environmental conditions such as high temperature. In this study, ceramic membranes with pore sizes of 80, 200 and 300 nm were individually mounted in three anaerobic ceramic membrane bioreactors (AnCMBRs) treating real domestic wastewater to examine the treatment efficiencies and to elucidate the effects of dissolved organic matters (DOMs) on fouling behaviours. The average overall chemical oxygen demands (COD) removal efficiencies could reach around 86-88%. Although CH4 productions were around 0.3 L/g CODutilised, about 67% of CH4 generated was dissolved in the liquid phase and lost in the permeate. When filtering mixed liquor of similar properties, smaller pore-sized membranes fouled slower in long-term operations due to lower occurrence of pore blockages. However, total organic removal efficiencies could not explain the fouling behaviours. Liquid chromatography-organic carbon detection, fluorescence spectrophotometer and high performance liquid chromatography coupled with fluorescence and ultra-violet detectors were used to analyse the DOMs in detail. The major foulants were identified to be biopolymers that were produced in microbial activities. One of the main components of biopolymers--proteins--led to different fouling behaviours. It is postulated that the proteins could pass through porous cake layers to create pore blockages in membranes. Hence, concentrations of the DOMs in the soluble fraction of mixed liquor (SML) could not predict membrane fouling because different components in the DOMs might have different interactions with membranes.

  2. Treatment of paper mill effluent using an anaerobic/aerobic hybrid side-stream membrane bioreactor.

    PubMed

    Sheldon, M S; Zeelie, P J; Edwards, W

    2012-01-01

    This paper presents the design and operational performance data of an anaerobic/aerobic hybrid side-stream Membrane Bioreactor (MBR) process for treating paper mill effluent operated over a 6 month period. The paper mill effluent stream was characterized by a chemical oxygen demand (COD) range of between 1,600 and 4,400 mg/L and an average BOD of 2,400 mg/L. Despite large fluctuations in COD feed concentration, stable process performance was achieved. The anaerobic Expanded Granular Sludge Bed (EGSB) pre-treatment step effectively lowered the organic loading by 65 to 85%, thus lowering the MBR COD feed concentration to consistently below 750 mg/L. The overall MBR COD removal was consistent at an average of 96%, regardless of the effluent COD or changes in the hydraulic retention time (HRT) and organic loading rate (OLR). Combining a high-rate anaerobic pre-treatment EGSB with a Modified Ludzack-Ettinger (MLE) MBR process configuration produced a high quality permeate. Preliminary NF and RO results indicated an overall COD removal of around 97 and 98%, respectively.

  3. Selection of suitable fertilizer draw solute for a novel fertilizer-drawn forward osmosis-anaerobic membrane bioreactor hybrid system.

    PubMed

    Kim, Youngjin; Chekli, Laura; Shim, Wang-Geun; Phuntsho, Sherub; Li, Sheng; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

    2016-06-01

    In this study, a protocol for selecting suitable fertilizer draw solute for anaerobic fertilizer-drawn forward osmosis membrane bioreactor (AnFDFOMBR) was proposed. Among eleven commercial fertilizer candidates, six fertilizers were screened further for their FO performance tests and evaluated in terms of water flux and reverse salt flux. Using selected fertilizers, bio-methane potential experiments were conducted to examine the effect of fertilizers on anaerobic activity due to reverse diffusion. Mono-ammonium phosphate (MAP) showed the highest biogas production while other fertilizers exhibited an inhibition effect on anaerobic activity with solute accumulation. Salt accumulation in the bioreactor was also simulated using mass balance simulation models. Results showed that ammonium sulfate and MAP were the most appropriate for AnFDFOMBR since they demonstrated less salt accumulation, relatively higher water flux, and higher dilution capacity of draw solution. Given toxicity of sulfate to anaerobic microorganisms, MAP appears to be the most suitable draw solution for AnFDFOMBR.

  4. Low energy single-staged anaerobic fluidized bed ceramic membrane bioreactor (AFCMBR) for wastewater treatment.

    PubMed

    Aslam, Muhammad; McCarty, Perry L; Shin, Chungheon; Bae, Jaeho; Kim, Jeonghwan

    2017-03-06

    An aluminum dioxide (Al2O3) ceramic membrane was used in a single-stage anaerobic fluidized bed ceramic membrane bioreactor (AFCMBR) for low-strength wastewater treatment. The AFCMBR was operated continuously for 395days at 25°C using a synthetic wastewater having a chemical oxygen demand (COD) averaging 260mg/L. A membrane net flux as high as 14.5-17L/m(2)h was achieved with only periodic maintenance cleaning, obtained by adding 25mg/L of sodium hypochlorite solution. No adverse effect of the maintenance cleaning on organic removal was observed. An average SCOD in the membrane permeate of 23mg/L was achieved with a 1h hydraulic retention time (HRT). Biosolids production averaged 0.014±0.007gVSS/gCOD removed. The estimated electrical energy required to operate the AFCMBR system was 0.039kWh/m(3), which is only about 17% of the electrical energy that could be generated with the methane produced.

  5. Micropollutants removal in an anaerobic membrane bioreactor and in an aerobic conventional treatment plant.

    PubMed

    Abargues, M R; Robles, A; Bouzas, A; Seco, A

    2012-01-01

    The paper expresses an attempt to tackle the problem due to the presence of micropollutants in wastewater which may be able to disrupt the endocrine system of some organisms. These kinds of compounds are ubiquitously present in municipal wastewater treatment plant (WWTP) effluents. The aim of this paper is to compare the fate of the alkylphenols-APs (4-(tert-octyl)) phenol, t-nonylphenol and 4-p-nonylphenol and the hormones (estrone, 17β-estradiol and 17α-ethinylestradiol) in a submerged anaerobic membrane bioreactor (SAMBR) pilot plant and in a conventional activated sludge wastewater treatment plant (CTP). The obtained results are also compared with the results obtained in a previous study carried out in an aerobic MBR pilot plant. The results showed that the APs soluble concentrations in the SAMBR effluent were always significantly higher than the CTP ones. Moreover, the analyses of the suspended fraction revealed that the AP concentrations in the SAMBR reactor were usually higher than in the CTP reactor, indicating that under anaerobic conditions the APs were accumulated in the digested sludge. The aerobic conditions maintained both in the CTP system and in the aerobic MBR favoured the APs and hormones degradation, and gave rise to lower concentrations in the effluent and in the reactor of these systems. Furthermore, the results also indicated that the degradation of APs under aerobic conditions was enhanced working at high solid retention time (SRT) and hydraulic retention time (HRT) values.

  6. Separation of competitive microorganisms using anaerobic membrane bioreactors as pretreatment to microbial electrochemical cells.

    PubMed

    Dhar, Bipro Ranjan; Gao, Yaohuan; Yeo, Hyeongu; Lee, Hyung-Sool

    2013-11-01

    Anaerobic membrane bioreactors (AnMBRs) as pretreatment to microbial electrochemical cells (MECs) were first assessed for improving energy recovery. A dual-chamber MEC was operated at hydraulic retention time (HRT) ranging from 1 to 8d, while operating conditions for an AnMBR were fixed. Current density was increased from 7.5 ± 0 to 14 ± 1A/m(2) membrane with increasing HRT. MEC tests with AnMBR permeate (mainly propionate and acetate) and propionate medium confirmed that propionate was fermented to acetate and hydrogen gas, and anode-respiring bacteria (ARB) utilized these fermentation products as substrate. Membrane separation in the AnMBR excluded fermenters and methanogens from the MEC, and thus no methane production was found in the MEC. The lack of fermenters, however, slowed down propionate fermentation rate, which limited current density in the MEC. To symphonize fermenters, H2-consumers, and ARB in biofilm anode is essential for improving current density, and COD removal.

  7. Performance of a submerged anaerobic membrane bioreactor with forward osmosis membrane for low-strength wastewater treatment.

    PubMed

    Chen, Lin; Gu, Yangshuo; Cao, Chuqing; Zhang, Jun; Ng, Jing-Wen; Tang, Chuyang

    2014-03-01

    A submerged anaerobic membrane bioreactor with forward osmosis membrane (FO-AnMBR) was operated at 25 °C for the treatment of synthetic wastewater. As the experiment progressed, the water flux reduced due to the membrane fouling and the increasing salinity in the reactor, and achieved at around 3.5 LMH in one cycle. It was worth noting that the level of salinity in the reactor was not a concern in terms of inhibition or toxic effects on the biological processes. The FO-AnMBR process exhibited greater than 96% removal of organic carbon, nearly 100% of total phosphorus and 62% of ammonia-nitrogen, respectively, suggesting a better removal efficiency than the conventional anaerobic membrane bioreactor. The methane and carbon dioxide compositions achieved concentrations of around 65%-78% and 22%-35%, respectively; and no obvious difference in the biogas composition was observed with the changes of conductivity. With respect to the methane yield, an average value of 0.21 L CH4 g(-1) COD was obtained, exhibiting the feasibility of energy recovery by this FO-AnMBR system. Additionally, an increase in the salinity enhanced the accumulation of soluble microbial products, especially for the proteins with 88.9% increment as the conductivity increased from 1.2 to 17.3 ms cm(-1). In contrast, a relatively stable concentration of extracellular polymer substances (EPS) was observed, indicating that the influence of conductivity on EPS cannot be directly correlated.

  8. Influence of total solids concentration on membrane permeability in a submerged hollow-fibre anaerobic membrane bioreactor.

    PubMed

    Robles, A; Durán, F; Ruano, M V; Ribes, J; Ferrer, J

    2012-01-01

    The main aim of this work was to study the influence of the mixed liquor total solids (MLTS) concentration on membrane permeability (K(20)) in a submerged anaerobic membrane bioreactor (SAnMBR) pilot plant, which is equipped with industrial hollow-fibre membranes and treats urban wastewater. This pilot plant was operated at 33 °C and 70 days of SRT. Two different transmembrane fluxes (13.3 and 10 LMH) were tested with a gas sparging intensity of 0.23 Nm(3) m(-2)h(-1) (measured as Specific Gas Demand referred to membrane area). A linear dependence of K(20) on MLTS concentration was observed within a range of MLTS concentration from 13 to 32 g L(-1) and J(20) of 10 LMH. K(20) was maintained at sustainable values (about 100 LMH bar(-1)) even at high MLTS concentrations (up to 20 g L(-1)). In addition, several short-tests were carried out when the membranes were operated at high MLTS concentrations in order to assess the effect of the physical cleaning strategies (relaxation and back-flush) on membrane performance. It was observed that, with the applied gas sparging intensity, the duration of the relaxation stage did not critically affect the membrane performance. On the other hand, the required back-flush frequency was considerably affected by the MLTS concentration.

  9. Post-treatment of the permeate of a submerged anaerobic membrane bioreactor (SAMBR) treating landfill leachate.

    PubMed

    Trzcinski, Antoine P; Ofoegbu, Nkechi; Stuckey, David C

    2011-01-01

    In this study, various methods were compared to reduce the Chemical Oxygen Demand (COD) content of stabilised leachate from a Submerged Anaerobic Membrane Bioreactor (SAMBR). It was found that Powdered Activated Carbon (PAC) resulted in greater COD removals (84 %) than Granular Activated Carbon (GAC-80 %), an ultrafiltration membrane of 1kDa (75 %), coagulation-flocculation with FeCl(3) and polyelectrolyte (45 %), FeCl(3) alone (32 %), and polymeric adsorbents such as XAD7HP (46 %) and XAD4 (32 %). Results obtained on the <1 kDa fraction showed that PAC and GAC had a similar adsorption efficiency of about 60 % COD removal, followed by XAD7HP (48 %), XAD4 (27 %) and then FeCl(3) (23 %). The post-treatment sequence UF+GAC would result in a final effluent with less than 100 mg COD/L. Size Exclusion Chromatography (SEC) revealed that the extent of adsorption of low MW compounds onto PAC was limited due to low MW hydrophilic compounds, whereas the kinetics of PAC adsorption depended mainly on the adsorption of high MW aromatics.

  10. Impacts of sludge retention time on sludge characteristics and membrane fouling in a submerged anaerobic-oxic membrane bioreactor.

    PubMed

    Zhang, Xiaomei; Yue, Xiuping; Liu, Zhiqiang; Li, Qingqing; Hua, Xiufu

    2015-06-01

    Anaerobic-oxic membrane bioreactor (AOMBR) has been proposed as a highly effective method in municipal and industrial wastewater treatment. In this study, according to the sewage treatment system in a campus, long-term experiments were conducted to assess the impacts of the sludge retention time (SRT) on sludge characteristics and membrane fouling, and the sludge parameters include biomass concentration, particle size distribution, extracellular polymeric substances (EPS), soluble microbial products (SMPs), and specific resistance to filtration (SRF). Our results clearly demonstrated that SRT was one of the most important factors influencing sludge characteristics, and different sludge characteristics resulted in different membrane fouling degrees. A better treatment and filtration performances were observed at the SRT of 30 days compared to two SRTs of 10 and 90 days. Among these parameters, SMP had the most significant correlation with the membrane fouling rate (dTMP/dt), and it had a negative impact on membrane filtration performance. The impact of SRT on membrane fouling process was discussed further by filtration models. At 10 days SRT, the complete-standard blocking model curve had a comparatively higher goodness-of-fit with the fouling process, and at 30 and 90 days SRT, the cake-standard blocking model curve had a relatively higher goodness-of-fit with respective fouling process.

  11. Trace metals supplementation in anaerobic membrane bioreactors treating highly saline phenolic wastewater.

    PubMed

    Muñoz Sierra, Julian David; Lafita, Carlos; Gabaldón, Carmen; Spanjers, Henri; van Lier, Jules B

    2017-06-01

    Biomass requires trace metals (TM) for maintaining its growth and activity. This study aimed to determine the effect of TM supplementation and partitioning on the specific methanogenic activity (SMA), with a focus on cobalt and tungsten, during the start-up of two lab-scale Anaerobic Membrane Bioreactors (AnMBRs) treating saline phenolic wastewater. The TM partitioning revealed a strong accumulation of sodium in the biomass matrix and a wash-out of the majority of TM in the reactors, which led to an SMA decrease and a low COD removal of about 30%. The SMA exhibits a maximum at about 6g Na(+) L(-1) and nearly complete inhibition at 34g Na(+) L(-1). The dose of 0.5mgL(-1) of tungsten increases the SMA by 17%, but no improvement was observed with the addition of cobalt. The results suggested that TM were not bioavailable at high salinity. Accordingly, an increased COD removal was achieved by doubling the supply of TM.

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

    PubMed

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

    2016-05-01

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

  13. Cultivation of Planktonic Anaerobic Ammonium Oxidation (Anammox) Bacteria Using Membrane Bioreactor

    PubMed Central

    Oshiki, Mamoru; Awata, Takanori; Kindaichi, Tomonori; Satoh, Hisashi; Okabe, Satoshi

    2013-01-01

    Enrichment cultures of anaerobic ammonium oxidation (anammox) bacteria as planktonic cell suspensions are essential for studying their ecophysiology and biochemistry, while their cultivation is still laborious. The present study aimed to cultivate two phylogenetically distinct anammox bacteria, “Candidatus Brocadia sinica” and “Ca. Scalindua sp.” in the form of planktonic cells using membrane bioreactors (MBRs). The MBRs were continuously operated for more than 250 d with nitrogen loading rates of 0.48–1.02 and 0.004–0.09 kgN m−3 d−1 for “Ca. Brocadia sinica” and “Ca. Scalindua sp.”, respectively. Planktonic anammox bacterial cells were successfully enriched (>90%) in the MBRs, which was confirmed by fluorescence in-situ hybridization and 16S rRNA gene sequencing analysis. The decay rate and half-saturation constant for NO2− of “Ca. Brocadia sinica” were determined to be 0.0029–0.0081 d−1 and 0.47 mgN L−1, respectively, using enriched planktonic cells. The present study demonstrated that MBR enables the culture of planktonic anammox bacterial cells, which are suitable for studying their ecophysiology and biochemistry. PMID:24200833

  14. Ammonium nitrogen removal from the permeates of anaerobic membrane bioreactors: economic regeneration of exhausted zeolite.

    PubMed

    Deng, Qiaosi; Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Lee, Hyung-Sool

    2014-08-01

    This study revealed that ammonium exchange of natural zeolite could be an economical method of nitrogen removal from the permeates of anaerobic membrane bioreactors (AnMBRs). It was found that the mass ratio of Na+ to Zeolite - NH4+ - N significantly affected regeneration efficiency (RE), not simply NaCI concentration. Batch experiments showed that the mass ratio of 750g Na+/g Zeolite - NH4+ - N was required to achieve RE over 90% in 2h at pH 9. However, the alkaline regeneration at pH 12 significantly decreased the mass ratio down to 4.2 in batch tests. It was confirmed that the alkaline regeneration only needed NaCl 10 g/L (the mass of Na+ to Zeolite - NH4+ - N of 4.2) for RE of 85% in 2 h of reaction time in continuous column tests. Economic analysis showed that this alkaline regeneration decreased chemical costs over 10 times as compared with a conventional regeneration method. A significant bottleneck of zeolite processes would be the requirement of substituting exhausted zeolite with virgin one, due to the reductions of ammonium exchange capacity and RE.

  15. Contribution of microfiltration on phosphorus removal in the sequencing anoxic/anaerobic membrane bioreactor.

    PubMed

    Cho, Jinwoo; Song, Kyung-Guen; Ahn, Kyu-Hong

    2009-08-01

    This study investigated the contribution of microfiltration to phosphorus removal in the sequencing anoxic/anaerobic membrane bioreactor. The phosphorus content in activated sludge was fractionated by the Schmidt-Thannhauser-Schneider method. The size distribution of phosphorus in the influent was analyzed to estimate the portion of particulate phosphorus rejected physically by the 0.2 mum microfiltration. The result was that along with the high removal of phosphorus (83%) the phosphorus content of activated sludge was measured as 58.66 mgP/gVSS corresponding to 5.87% on dry weight basis. About 9% of total phosphorus was chemically precipitated phosphates while 56% was stored inside the microbial cell by activity of PAOs, and 35% was the sum of minor intracellular compositions and the particulate residuals, which could be rejected completely by the microfiltration. The biological activity is the dominant way of phosphorus removal in the process. However, the microfiltration also contributed significantly to phosphorus removal by retaining the particulate phosphorus inside the system.

  16. A plant-wide energy model for wastewater treatment plants: application to anaerobic membrane bioreactor technology.

    PubMed

    Pretel, R; Robles, A; Ruano, M V; Seco, A; Ferrer, J

    2016-09-01

    The aim of this study is to propose a detailed and comprehensive plant-wide model for assessing the energy demand of different wastewater treatment systems (beyond the traditional activated sludge) in both steady- and unsteady-state conditions. The proposed model makes it possible to calculate power and heat requirements (W and Q, respectively), and to recover both power and heat from methane and hydrogen capture. In order to account for the effect of biological processes on heat requirements, the model has been coupled to the extended version of the BNRM2 plant-wide mathematical model, which is implemented in DESSAS simulation software. Two case studies have been evaluated to assess the model's performance: (1) modelling the energy demand of two urban wastewater treatment plants based on conventional activated sludge and submerged anaerobic membrane bioreactor (AnMBR) technologies in steady-state conditions and (2) modelling the dynamics of reactor temperature and heat requirements in an AnMBR plant in unsteady-state conditions. The results indicate that the proposed model can be used to assess the energy performance of different wastewater treatment processes and would thus be useful, for example, WWTP design or upgrading or the development of new control strategies for energy savings.

  17. The effect of solids retention time on dissolved methane concentration in anaerobic membrane bioreactors.

    PubMed

    Yeo, Hyeongu; Lee, Hyung-Sool

    2013-01-01

    We assessed the effect of solids retention times (SRT) on dissolved methane concentration in a lab-scale anaerobic membrane bioreactor (AnMBR) operated at SRT 20d and 40d at ambient temperature (23 +/- 1 degrees C). Daily methane production was 196 +/- 17 mL/d and 285 +/- 18 mL/d for SRT 20d and 40d, respectively. In comparison, the average concentration of dissolved methane in AnMBR permeates was 9.9 +/- 2.3 mg/L for SRT 20d (close to thermodynamic equilibrium), which was decreased to 4.3 +/- 0.3 mg/L for SRT 40d. We often found oversaturation of dissolved methane at SRT 20d, which means that mass transfer of dissolved methane from liquid to gas phase is dynamic at this short SRT. However, we never detected oversaturation of dissolved methane at SRT 40d, due to slow endogenous decay kinetics. Higher daily methane production at SRT 40d than that at SRT 20d indicates that methane was supplementarily produced from biomass electrons by endogenous decay. This study shows that operation of AnMBRs under long SRT can keep low dissolved methane concentration in AnMBR permeate, along with high methane yield.

  18. Characterization of the proton binding sites of extracellular polymeric substances in an anaerobic membrane bioreactor.

    PubMed

    Liu, Yi; Chang, Sheng; Defersha, Fantahun M

    2015-07-01

    This paper focuses on the characterization of the chemical compositions and acidic constants of the extracellular polymeric substances (EPSs) in an anaerobic membrane bioreactor treating synthetic brewery wastewater by using chemical analysis, linear programming analysis (LPA) of titration data, and FT-IR analysis. The linear programming analysis of titration data revealed that the EPSs have proton binding sites with pKa values from pKa ≤ 6, between 6 and 7, and approximately 9.8. The strong acidic sites (pKa ≤ 6) and some weak acidic sites (7.5 < pKa < 9.0) were found to be readily removed by 0.45-μm membrane filtration. In addition, the FT-IR analysis confirmed the presence of proteins, carbohydrates, nucleic acids, and lipids in the EPS samples. Based on the FT-IR analysis and the main chemical functional groups at the bacterial cell surfaces, the identified proton binding sites were related to carboxyl, phosphate, and hydroxyl/amine groups with pKa values of 4.6 ± 0.7, 6.6 ± 0.01, and 9.7 ± 0.1, respectively, with the corresponding respective intensities of 0.31 ± 0.05, 0.96 ± 0.3, and 1.53 ± 0.3 mmole/g-EPS. The pKa values and intensities of the proton binding sites are the fundamental molecular properties of EPSs that affect the EPS charge, molecular interactions, and metal complexation characteristics. Determination of such properties can advance Derjaguin-Landau-Verwey-Overbeek (DLVO)-based concentration polarization modeling, facilitate the estimation of the osmotic pressure of the EPS concentration polarization layers, and lead to a deeper understanding of the role of metal complexation in membrane fouling.

  19. A comparative study on the anaerobic membrane bioreactor performance during the treatment of domestic wastewaters of various origins.

    PubMed

    Saddoud, A; Ellouze, M; Dhouib, A; Sayadi, S

    2006-09-01

    This study examined the practical performance of a cross-flow ultrafiltration membrane coupled to an anaerobic bioreactor, for treatment of raw domestic wastewater (RDW), at a pilot-scale plant. Wastewaters used in this study originated from two different domestic wastewater treatment plans (DWTPs) (Sfax and Ksour Essef). During the treatment in the membrane bioreactor (MBR) of the RDW originating from Sfax DWTP, the bioreactor did not reach its stationary phase because the anaerobic biomass was unable to adapt to the wastewater. This was explained by the considerable fluctuations in the domestic wastewater composition and a possible contamination of Sfax wastewater by industrial discharges. However, the treatment of RDW originating from Ksour Essef (DWTP) was successful. In both cases, the treatment led to a total removal of all tested pathogens. The quality of treated wastewater fits largely with WHO guidelines for unrestricted irrigation. The phytotoxicity and the microtoxicity tests, using Lepidium sativum and Vibrio fischeri respectively, demonstrated that wastewater from Sfax exhibited higher toxicity than that from Ksour Sssef.

  20. Study on submerged anaerobic membrane bioreactor (SAMBR) treating high suspended solids raw tannery wastewater for biogas production.

    PubMed

    Umaiyakunjaram, R; Shanmugam, P

    2016-09-01

    This study deals with the treatment of high suspended solids raw tannery wastewater using flat sheet Submerged Anaerobic Membrane (0.4μm) Bioreactor (SAMBR) acclimatized with hypersaline anaerobic seed sludge for recovering biogas. The treatability of SAMBR achieved higher CODremoval efficiency (90%) and biogas yield (0.160L.g(-1) CODremoved) coincided with high r(2) values between permeate flux and TSS (0.95), biogas and COD removed (0.96). The acidification of hypersaline influent wastewater by biogas mixing with high CO2, achieved quadruplet benefit of gas liquid and solid separation, in-situ pH and NH3 control, in-situ CH4 enrichment, and prevention of membrane fouling. The initial high VFA became stable as time elapsed reveals the hydrolysing ability of particulate COD into soluble COD and into biogas, confirms the suitability of SAMBR for high suspended solids tannery wastewater.

  1. Development and application of a procedure for evaluating the long-term integrity of membranes for the anaerobic fluidized membrane bioreactor (AFMBR).

    PubMed

    Shin, Chungheon; Kim, Kihyun; McCarty, Perry L; Kim, Jeonghwan; Bae, Jaeho

    A bench-scale short-term test, developed to predict the long-term integrity of membranes with potential for use in anaerobic fluidized-bed membrane bioreactors, was used to evaluate several commercial hollow-fiber membranes. It was found that membrane performance varied widely, some membranes failing much more rapidly than others. Also found was that larger sizes of the fluidized media, in this case granular activated carbon (GAC), severely affected membrane structural integrity more than did smaller sizes, as did the method used for membrane attachment. Within the limits studied, the GAC packing ratio had only a minor impact. A decrease in membrane permeability that sometimes resulted during the testing and was caused by the deposition of fine GAC particles could be eliminated without membrane damage through simultaneous chemical cleaning and sonication. This new testing procedure should be useful for selecting membranes and reactor operating conditions to better ensure long-term operating performance of anaerobic fluidized-bed membrane bioreactors.

  2. Performance evaluation of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating ethanol thin stillage.

    PubMed

    Dereli, R K; Urban, D R; Heffernan, B; Jordan, J A; Ewing, J; Rosenberger, G T; Dunaev, T I

    2012-01-01

    The ethanol industry has grown rapidly during the past ten years, mainly due to increasing oil prices. However, efficient and cost-effective solutions for treating thin stillage wastewater have still to be developed. The anaerobic membrane bioreactor (AnMBR) technology combines classical anaerobic treatment in a completely-stirred tank reactor (CSTR) with membrane separation. The combination of these two technologies can achieve a superior effluent quality and also increase biogas production compared to conventional anaerobic solutions. A pilot-scale AnMBR treating thin stillage achieved very high treatment efficiencies in terms of chemical oxygen demand (COD) and total suspended solids (TSS) removal (>98%). An average permeate flux of 4.3 L/m2 x h was achieved at relatively low transmembrane pressure (TMP) values (0.1-0.2 bars) with flat-sheet membranes. Experience gained during the pilot-scale studies provides valuable information for scaling up of AnMBRs treating complex and high-strength wastewaters.

  3. Long term performance of membranes in an anaerobic membrane bioreactor treating municipal wastewater.

    PubMed

    Dong, Qirong; Parker, Wayne; Dagnew, Martha

    2016-02-01

    The long term impact of SRT (100-40 days) and recovery cleaning on membrane performance of an AnMBR treating authentic municipal wastewater in a large pilot plant was assessed. Successful operation of the pilot plant at a flux of 17 LMH was maintained for a period of 536 days during which the longest period of operation without recovery cleaning or membrane replacement was 178 days. Lower SRT (40 days) reduced the fouling propensity of the mixed liquor in terms of TSS concentration and the dewaterability indicators including colloidal COD (cCOD) concentration and capillary suction time (CST). Critical fluxes ranged from 21 to 23 LMH to 25-27 LMH for SRTs of 70 and 40 days respectively and this was consistent with the reduced concentrations of TSS and improved dewaterability under the latter conditions. Recovery cleaning was found to result in substantial reduction of resistance as indicated by both pilot plant operation and clean water flux tests. The long-term fouling rate was observed to be higher with cleaned membranes as compared to virgin membranes. The lower membrane fouling with virgin membranes suggested that accumulation of foulants, which were resistant to cleaning, caused the higher fouling rates for the cleaned membranes.

  4. Degradation of a model azo dye in submerged anaerobic membrane bioreactor (SAMBR) operated with powdered activated carbon (PAC).

    PubMed

    Baêta, B E L; Luna, H J; Sanson, A L; Silva, S Q; Aquino, S F

    2013-10-15

    This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in an upflow anaerobic sludge blanket reactor (UASB) and two submerged anaerobic membrane (SAMBR) bioreactors, one of which (SAMBR-1) was operated with powdered activated carbon (PAC) in its interior. The reactors were operated at 35 °C with a hydraulic retention time of 24 h in three operational phases, aimed to assess the effect of external sources of carbon (glucose) or redox mediator (yeast extract) on the removal or color and organic matter. The results showed that removal efficiencies of COD (73-94%) and color (90-94%) were higher for SAMBR-1 when compared to SAMBR-2 (operated without PAC) and UASB reactors. In addition, the presence of PAC in SAMBR-1 increased reactor stability, thereby leading to a lower accumulation of volatile fatty acids (VFA). The microfiltration membrane was responsible for an additional removal of ~50% of soluble residual COD in the form of VFA, thus improving permeate quality. On its turn, PAC exhibited the ability to adsorb byproducts (aromatic amines) of azo dye degradation as well as to act as source of immobilized redox mediator (quinone groups on its surface), thereby enhancing color removal.

  5. Evaluation and characterization during the anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor.

    PubMed

    Xiao, Xiaolan; Huang, Zhenxing; Ruan, Wenquan; Yan, Lintao; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing

    2015-10-01

    The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs.

  6. Effects of salinity build-up on the performance of an anaerobic membrane bioreactor regarding basic water quality parameters and removal of trace organic contaminants.

    PubMed

    Song, Xiaoye; McDonald, James; Price, William E; Khan, Stuart J; Hai, Faisal I; Ngo, Hao H; Guo, Wenshan; Nghiem, Long D

    2016-09-01

    The effects of elevated inorganic salt concentration on anaerobic membrane bioreactor (AnMBR) treatment regarding basic biological performance and trace organic contaminant (TrOC) removal were investigated. A set of 33 TrOCs were selected to represent pharmaceuticals, steroids, and pesticides in municipal wastewater. Results show potential adverse effects of increase in the bioreactor salinity to 15g/L (as NaCl) on the performance of AnMBR with respect to chemical oxygen demand removal, biogas production, and the removal of most hydrophilic TrOCs. Furthermore, a decrease in biomass production was observed as salinity in the bioreactor increased. The removal of most hydrophobic TrOCs was high and was not significantly affected by salinity build-up in the bioreactor. The accumulation of a few persistent TrOCs in the sludge phase was observed, but such accumulation did not vary significantly as salinity in the bioreactor increased.

  7. Control of struvite precipitation by selective removal of NH(4)+ with dialyzer/zeolite in an anaerobic membrane bioreactor.

    PubMed

    Kim, Junhong; Lee, Chung-Hak; Choo, Kwang-Ho

    2007-05-01

    This study focused on the mitigation of membrane fouling caused by struvite precipitation using a dialyzer/zeolite (D/Z) unit in an anaerobic membrane bioreactor. The D/Z unit was designed to selectively remove NH(4)+ ions, one of the main components of the inorganic foulant, struvite. The maximum mass transfer coefficient for NH(4)+ through the dialyzer was estimated to be 0.92 l m(-2)h(-1), whereas the Na-substituted zeolite had the highest ion exchange capacity with respect to ammonium among intact or differently pretreated zeolites. During a single passage of dialysate through the zeolite column, substantial NH(4)+ removal (in excess of 90%) was achieved, leading to the reduction in struvite precipitation in the digester. The D/Z unit played a significant role in controlling struvite precipitation, thereby enhancing permeate flux for the case of the ceramic membrane, in which struvite fouling would be more pronounced compared to the polymeric membrane. For the polymeric membrane, however, no significant improvement in flux was observed even with the D/Z unit because the fouling of the polymeric membrane was mainly due to the deposition of biomass rather than the struvite precipitation.

  8. Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community

    PubMed Central

    Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

    2016-01-01

    Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology. PMID:26830464

  9. Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community.

    PubMed

    Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

    2016-02-01

    Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology.

  10. Enhanced waste activated sludge digestion using a submerged anaerobic dynamic membrane bioreactor: performance, sludge characteristics and microbial community

    NASA Astrophysics Data System (ADS)

    Yu, Hongguang; Wang, Zhiwei; Wu, Zhichao; Zhu, Chaowei

    2016-02-01

    Anaerobic digestion (AD) plays an important role in waste activated sludge (WAS) treatment; however, conventional AD (CAD) process needs substantial improvements, especially for the treatment of WAS with low solids content and poor anaerobic biodegradability. Herein, we propose a submerged anaerobic dynamic membrane bioreactor (AnDMBR) for simultaneous WAS thickening and digestion without any pretreatment. During the long-term operation, the AnDMBR exhibited an enhanced sludge reduction and improved methane production over CAD process. Moreover, the biogas generated in the AnDMBR contained higher methane content than CAD process. Stable carbon isotopic signatures elucidated the occurrence of combined methanogenic pathways in the AnDMBR process, in which hydrogenotrophic methanogenic pathway made a larger contribution to the total methane production. It was also found that organic matter degradation was enhanced in the AnDMBR, thus providing more favorable substrates for microorganisms. Pyrosequencing revealed that Proteobacteria and Bacteroidetes were abundant in bacterial communities and Methanosarcina and Methanosaeta in archaeal communities, which played an important role in the AnDMBR system. This study shed light on the enhanced digestion of WAS using AnDMBR technology.

  11. Removal of steroid estrogens from municipal wastewater in a pilot scale expanded granular sludge blanket reactor and anaerobic membrane bioreactor

    PubMed Central

    Ito, Ayumi; Mensah, Lawson; Cartmell, Elise; Lester, John N.

    2016-01-01

    Anaerobic treatment of municipal wastewater offers the prospect of a new paradigm by reducing aeration costs and minimizing sludge production. It has been successfully applied in warm climates, but does not always achieve the desired outcomes in temperate climates at the biochemical oxygen demand (BOD) values of municipal crude wastewater. Recently the concept of ‘fortification' has been proposed to increase organic strength and has been demonstrated at the laboratory and pilot scale treating municipal wastewater at temperatures of 10–17°C. The process treats a proportion of the flow anaerobically by combining it with primary sludge from the residual flow and then polishing it to a high effluent standard aerobically. Energy consumption is reduced as is sludge production. However, no new treatment process is viable if it only addresses the problems of traditional pollutants (suspended solids – SS, BOD, nitrogen – N and phosphorus – P); it must also treat hazardous substances. This study compared three potential municipal anaerobic treatment regimes, crude wastewater in an expanded granular sludge blanket (EGSB) reactor, fortified crude wastewater in an EGSB and crude wastewater in an anaerobic membrane bioreactor. The benefits of fortification were demonstrated for the removal of SS, BOD, N and P. These three systems were further challenged with the removal of steroid estrogens at environmental concentrations from natural indigenous sources. All three systems removed these compounds to a significant degree, confirming that estrogen removal is not restricted to highly aerobic autotrophs, or aerobic heterotrophs, but is also a faculty of anaerobic bacteria. PMID:26212345

  12. Growth of Anaerobic Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in a High-Pressure Membrane Capsule Bioreactor

    PubMed Central

    Gieteling, Jarno; Widjaja-Greefkes, H. C. Aura; Plugge, Caroline M.; Stams, Alfons J. M.; Lens, Piet N. L.; Meulepas, Roel J. W.

    2014-01-01

    Communities of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) grow slowly, which limits the ability to perform physiological studies. High methane partial pressure was previously successfully applied to stimulate growth, but it is not clear how different ANME subtypes and associated SRB are affected by it. Here, we report on the growth of ANME-SRB in a membrane capsule bioreactor inoculated with Eckernförde Bay sediment that combines high-pressure incubation (10.1 MPa methane) and thorough mixing (100 rpm) with complete cell retention by a 0.2-μm-pore-size membrane. The results were compared to previously obtained data from an ambient-pressure (0.101 MPa methane) bioreactor inoculated with the same sediment. The rates of oxidation of labeled methane were not higher at 10.1 MPa, likely because measurements were done at ambient pressure. The subtype ANME-2a/b was abundant in both reactors, but subtype ANME-2c was enriched only at 10.1 MPa. SRB at 10.1 MPa mainly belonged to the SEEP-SRB2 and Eel-1 groups and the Desulfuromonadales and not to the typically found SEEP-SRB1 group. The increase of ANME-2a/b occurred in parallel with the increase of SEEP-SRB2, which was previously found to be associated only with ANME-2c. Our results imply that the syntrophic association is flexible and that methane pressure and sulfide concentration influence the growth of different ANME-SRB consortia. We also studied the effect of elevated methane pressure on methane production and oxidation by a mixture of methanogenic and sulfate-reducing sludge. Here, methane oxidation rates decreased and were not coupled to sulfide production, indicating trace methane oxidation during net methanogenesis and not anaerobic methane oxidation, even at a high methane partial pressure. PMID:25501484

  13. An enhanced anaerobic membrane bioreactor treating bamboo industry wastewater by bamboo charcoal addition: Performance and microbial community analysis.

    PubMed

    Xia, Tian; Gao, Xinyi; Wang, Caiqin; Xu, Xiangyang; Zhu, Liang

    2016-11-01

    In this study, two anaerobic membrane bioreactors (AnMBRs) were operated for 150days to treat bamboo industry wastewater (BIWW), and one of them was enhanced with bamboo charcoal (B-AnMBR). During the steady period, average chemical oxygen demand (COD) removal efficiencies of 94.5±2.9% and 89.1±3.1% were achieved in B-AnMBR and AnMBR, respectively. The addition of bamboo charcoal (BC) increased the amount of biomass and improved the performance of the systems. A higher biogas production and methane yield were also observed in B-AnMBR. Regarding the issue of membrane fouling, BC lowered the soluble microbial product (SMP) content by approximately 62.73mg/L and decreased the membrane resistance, thereby mitigating membrane fouling. Analysis of the microbial communities demonstrated that BC increased the microbial diversity and promoted the activity of Methanosaeta, Methanospirillum, and Methanobacterium, which are dominant in methane production.

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

    PubMed

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

    2016-03-01

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

  15. Graphene-Coated Hollow Fiber Membrane as the Cathode in Anaerobic Electrochemical Membrane Bioreactors--Effect of Configuration and Applied Voltage on Performance and Membrane Fouling.

    PubMed

    Werner, Craig M; Katuri, Krishna P; Hari, Ananda Rao; Chen, Wei; Lai, Zhiping; Logan, Bruce E; Amy, Gary L; Saikaly, Pascal E

    2016-04-19

    Electrically conductive, graphene-coated, hollow-fiber porous membranes were used as cathodes in anaerobic electrochemical membrane bioreactors (AnEMBRs) operated at different applied voltages (0.7 and 0.9 V) using a new rectangular reactor configuration compared to a previous tubular design (0.7 V). The onset of biofouling was delayed and minimized in rectangular reactors operated at 0.9 V compared to those at 0.7 V due to higher rates of hydrogen production. Maximum transmembrane pressures for the rectangular reactor were only 0.10 bar (0.7 V) or 0.05 bar (0.9 V) after 56 days of operation compared to 0.46 bar (0.7 V) for the tubular reactor after 52 days. The thickness of the membrane biofouling layer was approximately 0.4 μm for rectangular reactors and 4 μm for the tubular reactor. Higher permeate quality (TSS = 0.05 mg/L) was achieved in the rectangular AnEMBR than that in the tubular AnEMBR (TSS = 17 mg/L), likely due to higher current densities that minimized the accumulation of cells in suspension. These results show that the new rectangular reactor design, which had increased rates of hydrogen production, successfully delayed the onset of cathode biofouling and improved reactor performance.

  16. Experimental study of the anaerobic urban wastewater treatment in a submerged hollow-fibre membrane bioreactor at pilot scale.

    PubMed

    Giménez, J B; Robles, A; Carretero, L; Durán, F; Ruano, M V; Gatti, M N; Ribes, J; Ferrer, J; Seco, A

    2011-10-01

    The aim of this study was to assess the effect of several operational variables on both biological and separation process performance in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater. The pilot plant is equipped with two industrial hollow-fibre ultrafiltration membrane modules (PURON® Koch Membrane Systems, 30 m² of filtration surface each). It was operated under mesophilic conditions (at 33 °C), 70 days of SRT, and variable HRT ranging from 20 to 6h. The effects of the influent COD/SO₄-S ratio (ranging from 2 to 12) and the MLTS concentration (ranging from 6 to 22 g L⁻¹) were also analysed. The main performance results were about 87% of COD removal, effluent VFA below 20 mg L⁻¹ and biogas methane concentrations over 55% v/v. Methane yield was strongly affected by the influent COD/SO₄-S ratio. No irreversible fouling problems were detected, even for MLTS concentrations above 22 g L⁻¹.

  17. Performances of anaerobic and aerobic membrane bioreactors for the treatment of synthetic textile wastewater.

    PubMed

    Yurtsever, Adem; Sahinkaya, Erkan; Aktaş, Özgür; Uçar, Deniz; Çınar, Özer; Wang, Zhiwei

    2015-09-01

    This study aims at comparatively evaluating anaerobic and aerobic MBRs for the treatment of azo-dye containing synthetic wastewater. Also, the filtration performances of AnMBR and AeMBR were compared under similar operating conditions. In both MBRs, high COD removal efficiencies were observed. Although almost complete color removal was observed in AnMBR, only partial (30-50%) color removal was achieved in AeMBR. AnMBR was successfully operated up to 9 L/(m(2)h) (LMH) and no chemical cleaning was required at 4.5 LMH for around 50 days. AeMBR was operated successfully up to 20 LMH. The filtration resistance of AnMBR was generally higher compared to AeMBR although reversible fouling rates were comparable. In both MBRs, offline chemical cleaning with NaOCl and sulfuric acid almost completely removed irreversible fouling and the resistances of chemically cleaned membranes were close to those of new membranes.

  18. Anaerobic submerged membrane bioreactor (AnSMBR) for municipal wastewater treatment under mesophilic and psychrophilic temperature conditions.

    PubMed

    Martinez-Sosa, David; Helmreich, Brigitte; Netter, Thomas; Paris, Stefania; Bischof, Franz; Horn, Harald

    2011-11-01

    A pilot scale anaerobic submerged membrane bioreactor (AnSMBR) with an external filtration unit for municipal wastewater treatment was operated for 100 days. Besides gas sparging, additional shear was created by circulating sludge to control membrane fouling. During the first 69 days, the reactor was operated under mesophilic temperature conditions. Afterwards, the temperature was gradually reduced to 20 °C. A slow and linear increase in the filtration resistance was observed under critical flux conditions (7 L/(m2 h)) at 35 °C. However, an increase in the fouling rate probably linked to an accumulation of solids, a higher viscosity and soluble COD concentrations in the reactor was observed at 20 °C. The COD removal efficiency was close to 90% under both temperature ranges. Effluent COD and BOD5 concentrations were lower than 80 and 25 mg/L, respectively. Pathogen indicator microorganisms (fecal coliforms bacteria) were reduced by log(10)5. Hence, the effluent could be used for irrigation purposes in agriculture.

  19. Methanogenic degradation of toilet-paper cellulose upon sewage treatment in an anaerobic membrane bioreactor at room temperature.

    PubMed

    Chen, Rong; Nie, Yulun; Kato, Hiroyuki; Wu, Jiang; Utashiro, Tetsuya; Lu, Jianbo; Yue, Shangchao; Jiang, Hongyu; Zhang, Lu; Li, Yu-You

    2017-03-01

    Toilet-paper cellulose with rich but refractory carbon sources, are the main insoluble COD fractions in sewage. An anaerobic membrane bioreactor (AnMBR) was configured for sewage treatment at room temperature and its performance on methanogenic degradation of toilet paper was highlighted. The results showed, high organic removal (95%), high methane conversion (90%) and low sludge yield (0.08gVSS/gCOD) were achieved in the AnMBR. Toilet-paper cellulose was fully biodegraded without accumulation in the mixed liquor and membrane cake layer. Bioconversion efficiency of toilet paper approached 100% under a high organic loading rate (OLR) of 2.02gCOD/L/d and it could provide around 26% of total methane generation at most of OLRs. Long sludge retention time and co-digestion of insoluble/soluble COD fractions achieving mutualism of functional microorganisms, contributed to biodegradation of toilet-paper cellulose. Therefore the AnMBR successfully implemented simultaneously methanogenic bioconversion of toilet-paper cellulose and soluble COD in sewage at room temperature.

  20. Sustainable organic loading rate and energy recovery potential of mesophilic anaerobic membrane bioreactor for municipal wastewater treatment.

    PubMed

    Wei, Chun-Hai; Harb, Moustapha; Amy, Gary; Hong, Pei-Ying; Leiknes, TorOve

    2014-08-01

    The overall performance of a mesophilic anaerobic membrane bioreactor (AnMBR) for synthetic municipal wastewater treatment was investigated under a range of organic loading rate (OLR). A very steady and high chemical oxygen demand (COD) removal (around 98%) was achieved over a broad range of volumetric OLR of 0.8-10 gCOD/L/d. The sustainable volumetric and sludge OLR satisfying a permeate COD below 50 mg/L for general reuse was 6 gCOD/L/d and 0.63 gCOD/gMLVSS (mixed liquor volatile suspended solids)/d, respectively. At a high sludge OLR of over 0.6 gCOD/gMLVSS/d, the AnMBR achieved high methane production of over 300 ml/gCOD (even approaching the theoretical value of 382 ml/gCOD). A low biomass production of 0.015-0.026 gMLVSS/gCOD and a sustainable flux of 6L/m(2)/h were observed. The integration of a heat pump and forward osmosis into the mesophilic AnMBR process would be a promising way for net energy recovery from typical municipal wastewater in a temperate area.

  1. A membrane assisted hybrid bioreactor for the post treatment of an anaerobic effluent from a fish canning factory.

    PubMed

    Oyanedel, V; Garrido, J M; Lema, J M; Méndez, R

    2003-01-01

    An innovative membrane assisted hybrid bioreactor was used to treat a mixture of two streams produced in a fish canning factory: a highly loaded stream that had previously been treated in an anaerobic contact reactor, and a second stream with a relatively low COD and N concentration. Experiments were carried out during two experimental stages: an aerobic stage, which is focused in the study on the aerobic oxidation of ammonia and COD and a nitrification-denitrification stage in which the study was mainly focused on the removal of nitrogen. Results of the aerobic period pointed out that it was feasible to achieve ammonia and COD removals of around 99% at OLR of 6.5 kg COD/m3 x d and NLR of 1.8 kg N-NH4+/m3 x d. Specific nitrifying activities of up to 0.78 g N-NH4+/g protein x d and 0.25 g N-NH4+/g VSS x d, were recorded for the attached and suspended biomass, respectively. Around 50-60% of the nitrifying capacity of the reactor was a result of the nitrifying capacity of the biofilm. During the nitrification-denitrification stage 76% of nitrogen removal was attained at an NLR of 0.8 kg N-NH4+/m3 x d. The biofilm nitrifying activity was not affected by the operating conditions of the system, as a result of the preferential consumption of COD by suspended biomass in the reactor. Thus, the combination of a hybrid system, with both suspended and attached biomass, and an ultrafiltration membrane module might be an alternative for treating wastewaters in compact biological systems. The intrinsic characteristics of the system made it feasible to operate at high OLR without problems related with the settling properties of the sludge or the drop in the nitrogen conversion. There were no solids in the effluent as a result of the use of the membrane filtration module.

  2. Analysis of extracellular polymeric substance (EPS) release in anaerobic sludge holding tank and its effects on membrane fouling in a membrane bioreactor (MBR).

    PubMed

    Kim, Byeong-Cheol; Nam, Duck-Hyun; Na, Ji-Hun; Kang, Ki-Hoon

    2014-01-01

    Amongst sludge reduction strategies, the anaerobic side-stream sludge holding tank (SHT) is of particular interest because it has shown significant sludge reduction efficiency. However, due to the anaerobic and starving environment of the SHT, the release of extracellular polymeric substance (EPS) may be stimulated, and it may hamper the application of the SHT to the membrane bioreactor. In order to investigate the effect of sludge storage on EPS release, sludge samples from a pilot-scale sequencing batch reactor coupled with SHT was incubated in a series of bench-scale SHT reactors for different periods of time (0-24 h). The increase in EPS was not significant until 12 h of incubation (9.3%), while 40.9% of the increase was observed in the sample incubated for 24 h. The rapid increase in EPS concentration after 12 h indicates a greater rate of cell lysis than that with EPS consumption as substrate. Since inducing the initial stage of the endogenous phase within microorganisms is a key factor for the successful operation of the SHT for sludge reduction, the retention time for the SHT should be shorter than the time for the sudden increase in EPS release.

  3. The energy-saving anaerobic baffled reactor membrane bioreactor (EABR-MBR) system for recycling wastewater from a high-rise building.

    PubMed

    Ratanatamskul, Chavalit; Charoenphol, Chakraphan

    2015-01-01

    A novel energy-saving anaerobic baffled reactor-membrane bioreactor (EABR-MBR) system has been developed as a compact biological treatment system for reuse of water from a high-rise building. The anaerobic baffled reactor (ABR) compartment had five baffles and served as the anaerobic degradation zone, followed by the aerobic MBR compartment. The total operating hydraulic retention time (HRT) of the EABR-MBR system was 3 hours (2 hours for ABR compartment and very short HRT of 1 hour for aerobic MBR compartment). The wastewater came from the Charoen Wisawakam building. The results showed that treated effluent quality was quite good and highly promising for water reuse purposes. The average flux of the membrane was kept at 30 l/(m2h). The EABR-MBR system could remove chemical oxygen demand, total nitrogen and total phosphorus from building wastewater by more than 90%. Moreover, it was found that phosphorus concentration was rising in the ABR compartment due to the phosphorus release phenomenon, and then the concentration decreased rapidly in the aerobic MBR compartment due to the phosphorus uptake phenomenon. This implies that phosphorus-accumulating organisms inside the EABR-MBR system are responsible for biological phosphorus removal. The research suggests that the EABR-MBR system can be a promising system for water reuse and reclamation for high-rise building application in the near future.

  4. Effect of mean cell residence time on transmembrane flux, mixed-liquor characteristics and overall performance of a submerged anaerobic membrane bioreactor.

    PubMed

    Pacheco-Ruiz, Santiago; Heaven, Sonia; Banks, Charles J

    2017-05-01

    Kinetic control of Mean Cell Residence Time (MCRT) was shown to have a significant impact on membrane flux under steady-state conditions. Two laboratory-scale flat-plate submerged anaerobic membrane bioreactors were operated for 245 days on a low-to-intermediate strength substrate with high suspended solids. Transmembrane pressure was maintained at 2.2 kPa throughout four experimental phases, while MCRT in one reactor was progressively reduced. This allowed very accurate measurement of sustainable membrane flux rates at different MCRTs, and hence the degree of membrane fouling. Performance data were gathered on chemical oxygen demand (COD) removal efficiency, and a COD mass balance was constructed accounting for carbon converted into new biomass and that lost in the effluent as dissolved methane. Measurements of growth yield at each MCRT were made, with physical characterisation of each mixed liquor based on capillary suction time. The results showed membrane flux and MLSS filterability was highest at short MCRT, although specific methane production (SMP) was lower since a proportion of COD removal was accounted for by higher biomass yield. There was no advantage in operating at an MCRT <25 days. When considering the most suitable MCRT there is thus a trade-off between membrane performance, SMP and waste sludge yield.

  5. Effect of polyvinyl alcohol hydrogel as a biocarrier on volatile fatty acids production of a two-stage thermophilic anaerobic membrane bioreactor.

    PubMed

    Chaikasem, Supawat; Abeynayaka, Amila; Visvanathan, Chettiyappan

    2014-09-01

    This work studied the effect of polyvinyl alcohol hydrogel (PVA-gel) beads, as an effective biocarrier for volatile fatty acid (VFA) production in hydrolytic reactor of a two-stage thermophilic anaerobic membrane bioreactor (TAnMBR). The two-stage TAnMBR, treating synthetic high strength particulate wastewater with influent chemical oxygen demand (COD) [16.4±0.8 g/L], was operated at 55 °C. Under steady state conditions, the reactor was operated at an organic loading rate of 8.2±0.4 kg COD/m(3) d. Operational performance of the system was monitored by assessing VFA composition and quantity, methane production and COD removal efficiency. Increment of VFA production was observed with PVA-gel addition. Hydrolytic effluent contained large amount of acetic acid and n-butyric acid. However, increase in VFA production adversely affected the methanogenic reactor performance due to lack of methanogenic archaea.

  6. In-situ biogas sparging enhances the performance of an anaerobic membrane bioreactor (AnMBR) with mesh filter in low-strength wastewater treatment.

    PubMed

    Li, Na; Hu, Yi; Lu, Yong-Ze; Zeng, Raymond J; Sheng, Guo-Ping

    2016-07-01

    In the recent years, anaerobic membrane bioreactor (AnMBR) technology is being considered as a very attractive alternative for wastewater treatment due to the striking advantages such as upgraded effluent quality. However, fouling control is still a problem for the application of AnMBR. This study investigated the performance of an AnMBR using mesh filter as support material to treat low-strength wastewater via in-situ biogas sparging. It was found that mesh AnMBR exhibited high and stable chemical oxygen demand (COD) removal efficiencies with values of 95 ± 5 % and an average methane yield of 0.24 L CH4/g CODremoved. Variation of transmembrane pressure (TMP) during operation indicated that mesh fouling was mitigated by in-situ biogas sparging and the fouling rate was comparable to that of aerobic membrane bioreactor with mesh filter reported in previous researches. The fouling layer formed on the mesh exhibited non-uniform structure; the porosity became larger from bottom layer to top layer. Biogas sparging could not change the composition but make thinner thickness of cake layer, which might be benefit for reducing membrane fouling rate. It was also found that ultrasonic cleaning of fouled mesh was able to remove most foulants on the surface or pores. This study demonstrated that in-situ biogas sparging enhanced the performance of AnMBRs with mesh filter in low-strength wastewater treatment. Apparently, AnMBRs with mesh filter can be used as a promising and sustainable technology for wastewater treatment.

  7. Membrane Bioreactor With Pressure Cycle

    NASA Technical Reports Server (NTRS)

    Efthymiou, George S.; Shuler, Michael L.

    1991-01-01

    Improved class of multilayer membrane bioreactors uses convention forced by differences in pressure to overcome some of diffusional limitations of prior bioreactors. In reactor of new class, flow of nutrient solution reduces adverse gradients of concentration, keeps cells supplied with fresh nutrient, and sweeps away products faster than diffusion alone. As result, overall yield and rate of reaction increased. Pressures in sweeping gas and nutrient alternated to force nutrient liquid into and out of biocatalyst layer through hyrophilic membrane.

  8. Effects of internal recycling time mode and hydraulic retention time on biological nitrogen and phosphorus removal in a sequencing anoxic/anaerobic membrane bioreactor process.

    PubMed

    Song, Kyung-Guen; Cho, Jinwoo; Ahn, Kyu-Hong

    2009-01-01

    This study investigated the effects of internal recycling time mode and hydraulic retention time (HRT) on nutrient removal in the sequencing anoxic/anaerobic membrane bioreactor process. Denitrification and phosphorus release were reciprocally dependent on the anoxic/anaerobic time ratio (Ax/An). As Ax/An increased, nitrogen removal rate increased but phosphorus removal rate decreased. The increasing Ax/An provided the longer denitrification period so that the organic substrate were consumed more for denitrification rather than phosphorus release in the limited condition of readily biodegradable substrate. Decreasing HRT increased both nitrogen and phosphorus removal efficiency because as HRT decreased, food-to-microorganism loading ratio increased and thus enhanced the biological capacity and activity of denitrifying bacteria. This could be verified from the observation mixed liquor suspended solids concentration and specific denitrification rate. The change of Ax/An and HRT affected phosphorus removal more than nitrogen removal due to the limitation of favourable carbon source for phosphorus accumulating organisms.

  9. Navigating environmental, economic, and technological trade-offs in the design and operation of submerged anaerobic membrane bioreactors (AnMBRs).

    PubMed

    Pretel, R; Shoener, B D; Ferrer, J; Guest, J S

    2015-12-15

    Anaerobic membrane bioreactors (AnMBRs) enable energy recovery from wastewater while simultaneously achieving high levels of treatment. The objective of this study was to elucidate how detailed design and operational decisions of submerged AnMBRs influence the technological, environmental, and economic sustainability of the system across its life cycle. Specific design and operational decisions evaluated included: solids retention time (SRT), mixed liquor suspended solids (MLSS) concentration, sludge recycling ratio (r), flux (J), and specific gas demand per membrane area (SGD). The possibility of methane recovery (both as biogas and as soluble methane in reactor effluent) and bioenergy production, nutrient recovery, and final destination of the sludge (land application, landfill, or incineration) were also evaluated. The implications of these design and operational decisions were characterized by leveraging a quantitative sustainable design (QSD) framework which integrated steady-state performance modeling across seasonal temperatures (using pilot-scale experimental data and the simulating software DESASS), life cycle cost (LCC) analysis, and life cycle assessment (LCA). Sensitivity and uncertainty analyses were used to characterize the relative importance of individual design decisions, and to navigate trade-offs across environmental, economic, and technological criteria. Based on this analysis, there are design and operational conditions under which submerged AnMBRs could be net energy positive and contribute to the pursuit of carbon negative wastewater treatment.

  10. Effect of sludge retention time on the biological performance of anaerobic membrane bioreactors treating corn-to-ethanol thin stillage with high lipid content.

    PubMed

    Dereli, Recep Kaan; van der Zee, Frank P; Heffernan, Barry; Grelot, Aurelie; van Lier, Jules B

    2014-02-01

    The potential of anaerobic membrane bioreactors (AnMBRs) for the treatment of lipid rich corn-to-ethanol thin stillage was investigated at three different sludge retention times (SRT), i.e. 20, 30 and 50 days. The membrane assisted biomass retention in AnMBRs provided an excellent solution to sludge washout problems reported for the treatment of lipid rich wastewaters by granular sludge bed reactors. The AnMBRs achieved high COD removal efficiencies up to 99% and excellent effluent quality. Although higher organic loading rates (OLRs) up to 8.0 kg COD m(-3) d(-1) could be applied to the reactors operated at shorter SRTs, better biological degradation efficiencies, i.e. up to 83%, was achieved at increased SRTs. Severe long chain fatty acid (LCFA) inhibition was observed at 50 days SRT, possibly caused by the extensive dissolution of LCFA in the reactor broth, inhibiting the methanogenic biomass. Physicochemical mechanisms such as precipitation with divalent cations and adsorption on the sludge played an important role in the occurrence of LCFA removal, conversion, and inhibition.

  11. Effect of ammonium nitrogen concentration on the ammonia-oxidizing bacteria community in a membrane bioreactor for the treatment of anaerobically digested swine wastewater.

    PubMed

    Sui, Qianwen; Liu, Chong; Dong, Hongmin; Zhu, Zhiping

    2014-09-01

    A membrane bioreactor (MBR) was developed for the treatment of anaerobically digested swine wastewater and to investigate the effect of ammonium nitrogen concentration on biological nitrogen removal and ammonia-oxidizing bacteria (AOB) community structures. The MBR achieved a high NH4(+)-N removal efficiency of 0.08 kgNMLSS(-1)d(-1) and removed 95% of the influent NH4(+)-N. The TN removal rate was highest of 82.62% at COD/TN and BOD5/TN ratios of 8.76 ± 0.30 and 3.02 ± 0.09, respectively. With the decrease in ammonium nitrogen concentrations, the diversity of the AOB community declined and showed a simple pattern of DGGE. However, the AOB population size remained high, with abundance of 10(7)-10(9) copies mL(-1). With the decrease of ammonium nitrogen concentrations, Nitrosomonas eutropha gradually disappeared, whereas Nitrosomonas sp. OZK11 showed constant adaptability to survive during each treatment stage. The selective effect of ammonium concentration on AOB species could be due to the affinity for NH4(+)-N. In this study, the changes of ammonium nitrogen concentrations in digested swine wastewater were found to have selective effects on the composition of AOB community, and biological nitrogen removal was improved by optimising the influencing parameters.

  12. Combination of upflow anaerobic sludge blanket (UASB) and membrane bioreactor (MBR) for berberine reduction from wastewater and the effects of berberine on bacterial community dynamics.

    PubMed

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

    2013-02-15

    Berberine is a broad-spectrum antibiotic extensively used in personal medication. The production of berberine results in the generation of wastewater containing concentrated residual berberine. However, few related studies up to date focus on berberine removal from wastewaters. In this study, a lab-scale upflow anaerobic sludge blanket (UASB)-membrane bioreactor (MBR) process was developed for berberine removal from synthetic wastewater. The performance of the UASB-MBR system on berberine, COD and NH(4)(+)--N removal was investigated at different berberine loadings. And the effects of berberine on bacterial communities were evaluated using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results showed that, as the increase of berberine loadings, UASB performance was affected remarkably, whereas, efficient and stable performance of MBR ensured the overall removal rates of berberine, COD and NH(4)(+)--N consistently reached up to 99%, 98% and 98%, respectively. Significant shifts of bacterial community structures were detected in both UASB and MBR, especially in the initial operations. Along with the increase of berberine loadings, high antibiotic resisting species and some functional species, i.e. Acinetobacter sp., Clostridium sp., Propionibacterium sp., and Sphingomonas sp. in UASB, as well as Sphingomonas sp., Methylocystis sp., Hydrogenophaga sp. and Flavobacterium sp. in MBR were enriched in succession.

  13. Efficient performance and the microbial community changes of submerged anaerobic membrane bioreactor in treatment of sewage containing cellulose suspended solid at 25°C.

    PubMed

    Watanabe, Ryoya; Nie, Yulun; Takahashi, Shintaro; Wakahara, Shinichiro; Li, Yu-You

    2016-09-01

    Influence of cellulose as suspended solid (SS) on the performance of submerged anaerobic membrane bioreactor (SAnMBR) was evaluated at 25°C using two types of synthetic sewage (SS contained or not). During the 110days operation, COD and BOD removal, CH4 gas recovery and cellulose accumulation were investigated in detail. The influence of cellulose as SS in sewage on the SAnMBR performance was not significant at HRT longer than12h and 65-72% of the influent COD was recovered as methane gas at HRT of 12h. At HRT of 6h, the quality of effluent got worse and the accumulation of cellulose was found in reactor. 16S rRNA analysis revealed that the microbial diversity distribution including Archaea and Bacteria changed due to the addition of SS in sewage and specific microbe for cellulose degradation such as Proteobacteria was detected. Sludge in SAnMBR could acclimate to characteristics of sewage by self-adaptation.

  14. Feasibility of anaerobic membrane bioreactors (AnMBR) for onsite sanitation and resource recovery (nutrients, energy and water) in urban slums.

    PubMed

    Bair, Robert A; Ozcan, Onur Y; Ozcan, Onur O; Calabria, Jorge L; Dick, George H; Yeh, Daniel H

    2015-01-01

    Slums are challenging locations for sanitation technologies. High population densities, a lack of water and electricity infrastructure, and space constraints combine to ensure that many traditional waste treatment technologies fail when implemented in this context. This paper proposes the use of anaerobic membrane bioreactors (AnMBRs) for slum sanitation. AnMBRs allow for localized water reuse, high quality treatment, and energy production at the point of treatment. A water, energy, nutrient, and mass balance was conducted on a theoretical AnMBR directly coupled to a public toilet. The combined system would be capable of recycling its water for use in toilet flushing and would be capable of providing enough energy to power both the toilet and AnMBR operation. The addition of food waste to the feed would help to ensure process stability and energy production by the AnMBR. Ammonia accumulation within the system would have to be managed through struvite precipitation, ion exchange, oxidation, plant uptake or other means. Generated biogas can be converted into heat and/or electricity using small scale gas generators. AnMBR technology has high potential for success in slum settings, if considerations for maintenance and supplies are made as part of the design and system delivery.

  15. Metagenomic characterization of 'Candidatus Defluviicoccus tetraformis strain TFO71', a tetrad-forming organism, predominant in an anaerobic-aerobic membrane bioreactor with deteriorated biological phosphorus removal.

    PubMed

    Nobu, Masaru K; Tamaki, Hideyuki; Kubota, Kengo; Liu, Wen-Tso

    2014-09-01

    In an acetate-fed anaerobic-aerobic membrane bioreactor with deteriorated enhanced biological phosphorus removal (EBPR), Defluviicoccus-related tetrad-forming organisms (DTFO) were observed to predominate in the microbial community. Using metagenomics, a partial genome of the predominant DTFO, 'Candidatus Defluviicoccus tetraformis strain TFO71', was successfully constructed and characterized. Examining the genome confirmed the presence of genes related to the synthesis and degradation of glycogen and polyhydroxyalkanoate (PHA), which function as energy and carbon storage compounds. TFO71 and 'Candidatus Accumulibacter phosphatis' (CAP) UW-1 and CAP UW-2, representative polyphosphate-accumulating organisms (PAO), have PHA metabolism-related genes with high homology, but TFO71 has unique genes for PHA synthesis, gene regulation and granule management. We further discovered genes encoding DTFO polyphosphate (polyP) synthesis, suggesting that TFO71 may synthesize polyP under untested conditions. However, TFO71 may not activate these genes under EBPR conditions because the retrieved genome does not contain all inorganic phosphate transporters that are characteristic of PAOs (CAP UW-1, CAP UW-2, Microlunatus phosphovorus NM-1 and Tetrasphaera species). As a first step in characterizing EBPR-associated DTFO metabolism, this study identifies important differences between DTFO and PAO that may contribute to EBPR community competition and deterioration.

  16. Examination of Bacterial Characteristics of Anaerobic Membrane Bioreactors in Three Pilot-Scale Plants for Treating Low-Strength Wastewater by Application of the Colony-Forming-Curve Analysis Method

    PubMed Central

    Kataoka, Naoaki; Tokiwa, Yutaka; Tanaka, Yasuo; Fujiki, Kiichi; Taroda, Hiroyuki; Takeda, Kiyoshi

    1992-01-01

    Characteristic sludge ecosystems arising in anaerobic membrane bioreactors of three pilot-scale plants treating low-strength (less than 1 g of biological oxygen demand per liter) sewage or soybean-processing wastewater were examined by analysis of the colony-forming-curves (CFC) obtained by counting colonies at suitable intervals. The wastewaters, containing high amounts of suspended solids (SS) (SS/chemical oxygen demand ratio, 0.51 to 0.80), were treated by using two types of bioreactors: (i) a hydrolyzation reactor for solubilization and acidification of SS in wastewater and (ii) a methane fermentation reactor for producing methane. The colony counts for the two sewage treatment plants continued to increase even after 3 weeks of incubation, whereas those for soybean-processing wastewater reached an approximately constant level within 3 weeks of incubation. The CFCs were analyzed by correlating the rate of colony appearance on roll tubes with the physiological types of bacteria present in the bioreactors. It was found that there were large numbers of slow-colony-forming anaerobic bacteria within the bioreactors and that the viable populations consisted of a few groups with different growth rates. It is considered that the slow-growing colonies appearing after 10 days of incubation were the dominant microflora in the sewage treated by hydrolyzation reactors. In particular, highly concentrated sludge (30.0 g of mixed-liquor volatile SS per liter) retained by the membrane separation module contained a large number of such bacteria. Slow-growing colonies of these bacteria could be counted by using a sludge extract medium prepared from only the supernatant of autoclaved sludge. In addition, the highest colony counts were almost always obtained with the sludge extract medium, meaning that most of the anaerobic bacteria in these sludges have complex nutrient requirements for growth. This report also indicates the usefulness of application of the CFC analysis method to

  17. A two-stage microbial fuel cell and anaerobic fluidized bed membrane bioreactor (MFC-AFMBR) system for effective domestic wastewater treatment.

    PubMed

    Ren, Lijiao; Ahn, Yongtae; Logan, Bruce E

    2014-04-01

    Microbial fuel cells (MFCs) are a promising technology for energy-efficient domestic wastewater treatment, but the effluent quality has typically not been sufficient for discharge without further treatment. A two-stage laboratory-scale combined treatment process, consisting of microbial fuel cells and an anaerobic fluidized bed membrane bioreactor (MFC-AFMBR), was examined here to produce high quality effluent with minimal energy demands. The combined system was operated continuously for 50 days at room temperature (∼25 °C) with domestic wastewater having a total chemical oxygen demand (tCOD) of 210 ± 11 mg/L. At a combined hydraulic retention time (HRT) for both processes of 9 h, the effluent tCOD was reduced to 16 ± 3 mg/L (92.5% removal), and there was nearly complete removal of total suspended solids (TSS; from 45 ± 10 mg/L to <1 mg/L). The AFMBR was operated at a constant high permeate flux of 16 L/m(2)/h over 50 days, without the need or use of any membrane cleaning or backwashing. Total electrical energy required for the operation of the MFC-AFMBR system was 0.0186 kWh/m(3), which was slightly less than the electrical energy produced by the MFCs (0.0197 kWh/m(3)). The energy in the methane produced in the AFMBR was comparatively negligible (0.005 kWh/m(3)). These results show that a combined MFC-AFMBR system could be used to effectively treat domestic primary effluent at ambient temperatures, producing high effluent quality with low energy requirements.

  18. Waste to Energy Potential - A High Concentration Anaerobic Bioreactor

    DTIC Science & Technology

    2012-05-23

    output • Uses the organic portion of solid waste (such as food waste , paper products, and agricultural waste ) to fuel an anaerobic digestion ...Sustainability Symposium & Exhibition Anaerobic Digestion • What does it do? • Offers sustainability by addressing renewable energy, waste ... Waste to Energy Potential – A High Concentration Anaerobic Bioreactor Presenter: Scott Murphy & Rebecca Robbennolt ARCADIS/Malcolm Pirnie Date

  19. Membrane bioreactors for water reclamation.

    PubMed

    Tao, G; Kekre, K; Wei, Z; Lee, T C; Viswanath, B; Seah, H

    2005-01-01

    Singapore has been using dual membrane technology (MF/UF RO) to produce high-grade water (NEWater) from secondary treated sewage. Membrane bioreactor (MBR) has very high potential and will lead to the further improvement of the productivity and quality of high-grade water. This study was focused on the technical feasibility of MBR system for water reclamation in Singapore, making a comparison between various membrane systems available and to get operational experience in terms of membrane cleaning and other issues. Three MBR plants were built at Bedok Water Reclamation Plant with a design flow of 300 m3/day each. They were commissioned in March 2003. Three different types of submerged membranes were tested. They are Membrane A, plate sheet membrane with pore size of 0.4 microm; Membrane B, hollow fibre membrane with pore size of 0.4 microm; and Membrane C, hollow fibre membrane with pore size of 0.035 microm. The permeate quality of all the three MBR Systems were found equivalent to or better than that of the conventional tertiary treatment by ultrafiltration. MBR permeate TOC was about 2 mg/l lower than UF permeate TOC. GC-MS, GC-ECD and HPLC scan results show that trace organic contaminants in MBR permeate and UF permeate were in the same range. MBR power consumption can be less than 1 kwh/m3. Gel layer or dynamic membrane generated on the submerged membrane surface played an important role for the lower MBR permeate TOC than the supernatant TOC in the membrane tank. Intensive chemical cleaning can temporarily remove this layer. During normal operation conditions, the formation of dynamic membrane may need one day to obtain the steady low TOC levels in MBR permeate.

  20. Treatment of textile wastewater with membrane bioreactor: A critical review.

    PubMed

    Jegatheesan, Veeriah; Pramanik, Biplob Kumar; Chen, Jingyu; Navaratna, Dimuth; Chang, Chia-Yuan; Shu, Li

    2016-03-01

    Membrane bioreactor (MBR) technology has been used widely for various industrial wastewater treatments due to its distinct advantages over conventional bioreactors. Treatment of textile wastewater using MBR has been investigated as a simple, reliable and cost-effective process with a significant removal of contaminants. However, a major drawback in the operation of MBR is membrane fouling, which leads to the decline in permeate flux and therefore requires membrane cleaning. This eventually decreases the lifespan of the membrane. In this paper, the application of aerobic and anaerobic MBR for textile wastewater treatment as well as fouling and control of fouling in MBR processes have been reviewed. It has been found that long sludge retention time increases the degradation of pollutants by allowing slow growing microorganisms to establish but also contributes to membrane fouling. Further research aspects of MBR for textile wastewater treatment are also considered for sustainable operations of the process.

  1. On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

    NASA Technical Reports Server (NTRS)

    Colon, Guillermo

    1995-01-01

    The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found

  2. Proteins causing membrane fouling in membrane bioreactors.

    PubMed

    Miyoshi, Taro; Nagai, Yuhei; Aizawa, Tomoyasu; Kimura, Katsuki; Watanabe, Yoshimasa

    2015-01-01

    In this study, the details of proteins causing membrane fouling in membrane bioreactors (MBRs) treating real municipal wastewater were investigated. Two separate pilot-scale MBRs were continuously operated under significantly different operating conditions; one MBR was a submerged type whereas the other was a side-stream type. The submerged and side-stream MBRs were operated for 20 and 10 days, respectively. At the end of continuous operation, the foulants were extracted from the fouled membranes. The proteins contained in the extracted foulants were enriched by using the combination of crude concentration with an ultrafiltration membrane and trichloroacetic acid precipitation, and then separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The N-terminal amino acid sequencing analysis of the proteins which formed intensive spots on the 2D-PAGE gels allowed us to partially identify one protein (OmpA family protein originated from genus Brevundimonas or Riemerella anatipestifer) from the foulant obtained from the submerged MBR, and two proteins (OprD and OprF originated from genus Pseudomonas) from that obtained from the side-stream MBR. Despite the significant difference in operating conditions of the two MBRs, all proteins identified in this study belong to β-barrel protein. These findings strongly suggest the importance of β-barrel proteins in developing membrane fouling in MBRs.

  3. Characteristics, process parameters, and inner components of anaerobic bioreactors.

    PubMed

    Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na

    2014-01-01

    The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive.

  4. Comparison between mixed liquors of two side-stream membrane bioreactors treating wastewaters from waste management plants with high and low solids anaerobic digestion.

    PubMed

    Zuriaga-Agustí, E; Mendoza-Roca, J A; Bes-Piá, A; Alonso-Molina, J L; Fernández-Giménez, E; Álvarez-Requena, C; Muñagorri-Mañueco, F; Ortiz-Villalobos, G

    2016-09-01

    In the last years, biological treatment plants for the previously separated organic fraction from municipal solid wastes (OFMSW) have gained importance. In these processes a liquid effluent (liquid fraction from the digestate and leachate from composting piles), which has to be treated previously to its discharge, is produced. In this paper, the characteristics of the mixed liquor from two full-scale membrane bioreactors treating the effluents of two OFMSW treatment plants have been evaluated in view to study their influence on membrane fouling in terms of filterability. For that, the mixed liquor samples have been ultrafiltrated in an UF laboratory plant. Besides, the effect of the influent characteristics to MBRs and the values of the chemical and physical parameters of the mixed liquors on the filterability have been studied. Results showed that the filterability of the mixed liquor was strongly influenced by the soluble microbial products in the mixed liquors and the influent characteristics to MBR. Permeate flux of MBR mixed liquor treating the most polluted wastewater was considerable the lowest (around 20 L/m(2) h for some samples), what was explained by viscosity and soluble microbial products concentration higher than those measured in other MBR mixed liquor.

  5. The influence of hydrolysis induced biopolymers from recycled aerobic sludge on specific methanogenic activity and sludge filterability in an anaerobic membrane bioreactor.

    PubMed

    Buntner, D; Spanjers, H; van Lier, J B

    2014-03-15

    The objective of the present study was to evaluate the impact of excess aerobic sludge on the specific methanogenic activity (SMA), in order to establish the maximum allowable aerobic sludge loading. In batch tests, different ratios of aerobic sludge to anaerobic inoculum were used, i.e. 0.03, 0.05, 0.10 and 0.15, showing that low ratios led to an increased SMA. However, the ratio 0.15 caused more than 20% SMA decrease. In addition to the SMA tests, the potential influence of biopolymers and extracellular substances, that are generated as a result of excess aerobic sludge hydrolysis, on membrane performance was determined by assessing the fouling potential of the liquid broth, taking into account parameters such as specific resistance to filtration (SRF) and supernatant filterability (SF). Addition of aerobic sludge to the anaerobic biomass resulted in a high membrane fouling potential. The increase in biopolymers could be ascribed to aerobic sludge hydrolysis. A clear positive correlation between the concentration of the colloidal fraction of biopolymer clusters (cBPC) and the SRF was observed and a negative correlation between the cBPC and the SF measured at the end of the above described SMA tests. The latter implies that sludge filtration resistance increases when more aerobic sludge is hydrolyzed, and thus more cBPC is released. During AnMBR operation, proteins significantly contributed to sludge filterability decrease expressed as SRF and SF, whereas the carbohydrate fraction of SMP was of less importance due to low concentrations. On the contrary, carbohydrates seemed to improve filterability and diminish SRF of the sludge. Albeit, cBPC increase caused an increase in mean TMP during the AnMBR operation, confirming that cBPC is positively correlated to membrane fouling.

  6. [Printing and dyeing wastewater treatment using combined process of anaerobic bioreactor and MBR].

    PubMed

    Zheng, Xiang; Liu, Jun-xin

    2004-09-01

    This paper describes a labor-scale experiment for printing and dyeing wastewater treatment of woolen mill using a combined process of an anaerobic reactor and a membrane bioreactor (MBR). The experimental results showed that when the concentration of COD, BOD5 and color in the influent were 128-321 mg/L, 36-95 mg/L and 40-70 dilution times (DT), the average concentrations of COD, BOD5, color and turbidity in the effluent were 36.9 mg/L, 3.7 mg/L, 21 DT and 0.24 NTU, respectively, and the corresponding removal rates were 80.3%, 95%, 59% and 99.3%, respectively. A new integrated membrane bioreactor by gravity drain of liquid level in the bioreactor was developed in this study. It not only lessens suction pump for effluent and controlling unit comparing to the traditional integrated membrane bioreactor, but also has the characters of high and continuous flux, concise configuration and simple operation and maintenance. According to the experimental results, the air flow rate through the membrane module is a significant factor to affect the flux rate and cake layer deposited on the membrane. With application of optimal air flow rate, it is effective to reduce membrane fouling and maintain high flux rate.

  7. Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review

    NASA Astrophysics Data System (ADS)

    Hassan, Siti Roshayu; Dahlan, Irvan

    2013-09-01

    Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

  8. [Resistance analyses for recirculated membrane bioreactor].

    PubMed

    Yang, Qi; Huang, Xia; Shang, Hai-Tao; Wen, Xiang-Hua; Qian, Yi

    2006-11-01

    The resistance analyses for recirculated membrane bioreactor by the resistance-in-series model and the modified gel-polarization model respectively were extended to the turbulent ultrafiltration system. The experiments are carried out by dye wastewater in a tubular membrane module, it is found that the permeate fluxes are predicted very well by these models for turbinate systems. And the resistance caused by the concentration polarization is studied; the gel layer resistance is the most important of all the resistances.

  9. Using a membrane bioreactor to reclaim wastewater

    SciTech Connect

    Cicek, N.; Franco, J.P.; Suidan, M.T.; Urbain, V.

    1998-11-01

    A pilot-scale membrane bioreactor sufficiently purified simulated municipal wastewater for indirect recharge to groundwater or nonpotable uses. Throughout more than 500 days of steady-state operation, total organic carbon concentrations of <1.1 mg/L and chemical oxygen demand of <3.5 mg/L were consistently achieved. No suspended solids were detected in the effluent during this period. The treated water was fully nitrified, resulting in low ammonia and organic nitrogen concentrations but high nitrate concentrations. Cyclic oxic-anoxic operation of an additional denitrification process would be necessary to meet potable water reuse standards. Phosphorus was fully used in the bioreactor for biological growth. Heterotrophic bacteria and MS-2 viruses were completely retained by the membrane system, reducing the extent of final disinfection required.

  10. Membrane biofouling by extracellular polymeric substances or soluble microbial products from membrane bioreactor sludge.

    PubMed

    Ramesh, A; Lee, D J; Lai, J Y

    2007-03-01

    This study extracted the soluble microbial products and loosely bound and tightly bound extracellular polymeric substances (EPS) from suspended sludge from a membrane bioreactor, original and aerobically/anaerobically digested, and compared their fouling potentials on a microfiltration membrane. The resistance of cake layer accounts for 95-98% of the total filtration resistances when filtering the whole sludges, with anaerobically digested sludge presenting the highest resistance among the three tested sludges. The tightly bound EPS has the highest potential to foul the membrane; however, the loosely bound EPS contribute most of the filtration resistances of the whole sludges. The foulants corresponding to the irreversible fouling have chemical fingerprints similar to those from loosely bound EPS, which have a greater predilection to proteins and humic substances than to polysaccharides.

  11. Enhanced membrane bioreactor process without chemical cleaning.

    PubMed

    Krause, S; Zimmermann, B; Meyer-Blumenroth, U; Lamparter, W; Siembida, B; Cornel, P

    2010-01-01

    In membrane bioreactors (MBR) for wastewater treatment, the separation of activated sludge and treated water takes place by membrane filtration. Due to the small footprint and superior effluent quality, the number of membrane bioreactors used in wastewater treatment is rapidly increasing. A major challenge in this process is the fouling of the membranes which results in permeability decrease and the demand of chemical cleaning procedures. With the objective of a chemical-free process, the removal of the fouling layer by continuous physical abrasion was investigated. Therefore, particles (granules) were added to the activated sludge in order to realise a continuous abrasion of the fouling layer. During operation for more than 8 months, the membranes showed no decrease in permeability. Fluxes up to 40 L/(m(2) h) were achieved. An online turbidity measurement was installed for the effluent control and showed no change during this test period. For comparison, a reference (standard MBR process without granules) was operated which demonstrated permeability loss at lower fluxes and required chemical cleaning. Altogether with this process an operation at higher fluxes and no use of cleaning chemicals will increase the cost efficiency of the MBR-process.

  12. Ultrastructure and Viral Metagenome of Bacteriophages from an Anaerobic Methane Oxidizing Methylomirabilis Bioreactor Enrichment Culture

    PubMed Central

    Gambelli, Lavinia; Cremers, Geert; Mesman, Rob; Guerrero, Simon; Dutilh, Bas E.; Jetten, Mike S. M.; Op den Camp, Huub J. M.; van Niftrik, Laura

    2016-01-01

    With its capacity for anaerobic methane oxidation and denitrification, the bacterium Methylomirabilis oxyfera plays an important role in natural ecosystems. Its unique physiology can be exploited for more sustainable wastewater treatment technologies. However, operational stability of full-scale bioreactors can experience setbacks due to, for example, bacteriophage blooms. By shaping microbial communities through mortality, horizontal gene transfer, and metabolic reprogramming, bacteriophages are important players in most ecosystems. Here, we analyzed an infected Methylomirabilis sp. bioreactor enrichment culture using (advanced) electron microscopy, viral metagenomics and bioinformatics. Electron micrographs revealed four different viral morphotypes, one of which was observed to infect Methylomirabilis cells. The infected cells contained densely packed ~55 nm icosahedral bacteriophage particles with a putative internal membrane. Various stages of virion assembly were observed. Moreover, during the bacteriophage replication, the host cytoplasmic membrane appeared extremely patchy, which suggests that the bacteriophages may use host bacterial lipids to build their own putative internal membrane. The viral metagenome contained 1.87 million base pairs of assembled viral sequences, from which five putative complete viral genomes were assembled and manually annotated. Using bioinformatics analyses, we could not identify which viral genome belonged to the Methylomirabilis- infecting bacteriophage, in part because the obtained viral genome sequences were novel and unique to this reactor system. Taken together these results show that new bacteriophages can be detected in anaerobic cultivation systems and that the effect of bacteriophages on the microbial community in these systems is a topic for further study. PMID:27877158

  13. Removal of tetrachloroethylene in an anaerobic column bioreactor.

    PubMed

    Noftsker, C; Watwood, M E

    1997-09-01

    Removal of tetrachloroethylene (perchloroethylene; C2Cl4) by microbial consortia from two sites with different C2Cl4 exposure histories was examined in a bench-scale anaerobic column bioreactor. It was hypothesized that optimal removal would be observed in the reactor packed with sediments having an extensive exposure history. Microbial consortia were enriched from hyporheic-zone (HZ) sediments from the Portneuf aquifer near Pocatello, Idaho, and from industrial-zone (IZ) sediments from a highly contaminated aquifer in Portland, Oregon. Lactate and acetate were the electron donors during experiments conducted over 9 and 7 months for HZ and IZ sediments, respectively. In the HZ bioreactor, the retention time ranged from 31 h to 81 h, and inlet C2Cl4 concentrations ranged from 0.1 ppm to 1.0 ppm. Dechlorination of C2Cl4 averaged 60% and reached a maximum of 78%. An increase in C:N from 27:1 to 500:1 corresponded to an 18% increase in removal efficiency. Trichloroethylene production corresponded to decreased effluent C2Cl4; further intermediates were not detected. In the IZ bioreactor, the retention time varied from 34 h to 115 h; the inlet C2Cl4 concentration was 1.0 ppm. C2Cl4 removal averaged 70% with a maximum of 98%. Trichloroethylene and cis-dichloroethylene were detected in the effluent. Increases in C:N from 50:1 to 250:1 enhanced dechlorination activity.

  14. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane.

    PubMed

    Ho, J; Smith, S; Roh, H K

    2014-01-01

    A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m(2)/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m(3) permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m(3)). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude.

  15. A comparative study of leachate quality and biogas generation in simulated anaerobic and hybrid bioreactors.

    PubMed

    Xu, Qiyong; Tian, Ying; Wang, Shen; Ko, Jae Hac

    2015-07-01

    Research has been conducted to compare leachate characterization and biogas generation in simulated anaerobic and hybrid bioreactor landfills with typical Chinese municipal solid waste (MSW). Three laboratory-scale reactors, an anaerobic (A1) and two hybrid bioreactors (C1 and C2), were constructed and operated for about 10months. The hybrid bioreactors were operated in an aerobic-anaerobic mode with different aeration frequencies by providing air into the upper layer of waste. Results showed that the temporary aeration into the upper layer aided methane generation by shortening the initial acidogenic phase because of volatile fatty acids (VFAs) reduction and pH increase. Chemical oxygen demand (COD) decreased faster in the hybrid bioreactors, but the concentrations of ammonia-nitrogen in the hybrid bioreactors were greater than those in the anaerobic control. Methanogenic conditions were established within 75d and 60d in C1 and C2, respectively. However, high aeration frequency led to the consumption of organic matters by aerobic degradation and resulted in reducing accumulative methane volume. The temporary aeration enhanced waste settlement and the settlement increased with increasing the frequency of aeration. Methane production was inhibited in the anaerobic control; however, the total methane generations from hybrid bioreactors were 133.4L/kgvs and 113.2L/kgvs. As for MSW with high content of food waste, leachate recirculation right after aeration stopped was not recommended due to VFA inhibition for methanogens.

  16. A comparative study of leachate quality and biogas generation in simulated anaerobic and hybrid bioreactors

    SciTech Connect

    Xu, Qiyong; Tian, Ying; Wang, Shen; Ko, Jae Hac

    2015-07-15

    Highlights: • Temporary aeration shortened the initial acid inhibition phase for methanogens. • COD decreased faster in the hybrid bioreactor than that in the anaerobic control. • Methane generations from hybrid bioreactors were 133.4 L/kg{sub vs} and 113.2 L/kg{sub vs}. • MSW settlement increased with increasing the frequency of intermittent aeration. - Abstract: Research has been conducted to compare leachate characterization and biogas generation in simulated anaerobic and hybrid bioreactor landfills with typical Chinese municipal solid waste (MSW). Three laboratory-scale reactors, an anaerobic (A1) and two hybrid bioreactors (C1 and C2), were constructed and operated for about 10 months. The hybrid bioreactors were operated in an aerobic–anaerobic mode with different aeration frequencies by providing air into the upper layer of waste. Results showed that the temporary aeration into the upper layer aided methane generation by shortening the initial acidogenic phase because of volatile fatty acids (VFAs) reduction and pH increase. Chemical oxygen demand (COD) decreased faster in the hybrid bioreactors, but the concentrations of ammonia–nitrogen in the hybrid bioreactors were greater than those in the anaerobic control. Methanogenic conditions were established within 75 d and 60 d in C1 and C2, respectively. However, high aeration frequency led to the consumption of organic matters by aerobic degradation and resulted in reducing accumulative methane volume. The temporary aeration enhanced waste settlement and the settlement increased with increasing the frequency of aeration. Methane production was inhibited in the anaerobic control; however, the total methane generations from hybrid bioreactors were 133.4 L/kg{sub vs} and 113.2 L/kg{sub vs}. As for MSW with high content of food waste, leachate recirculation right after aeration stopped was not recommended due to VFA inhibition for methanogens.

  17. Hydrodynamics of an Electrochemical Membrane Bioreactor

    PubMed Central

    Wang, Ya-Zhou; Wang, Yun-Kun; He, Chuan-Shu; Yang, Hou-Yun; Sheng, Guo-Ping; Shen, Jin-You; Mu, Yang; Yu, Han-Qing

    2015-01-01

    An electrochemical membrane bioreactor (EMBR) has recently been developed for energy recovery and wastewater treatment. The hydrodynamics of the EMBR would significantly affect the mass transfers and reaction kinetics, exerting a pronounced effect on reactor performance. However, only scarce information is available to date. In this study, the hydrodynamic characteristics of the EMBR were investigated through various approaches. Tracer tests were adopted to generate residence time distribution curves at various hydraulic residence times, and three hydraulic models were developed to simulate the results of tracer studies. In addition, the detailed flow patterns of the EMBR were acquired from a computational fluid dynamics (CFD) simulation. Compared to the tank-in-series and axial dispersion ones, the Martin model could describe hydraulic performance of the EBMR better. CFD simulation results clearly indicated the existence of a preferential or circuitous flow in the EMBR. Moreover, the possible locations of dead zones in the EMBR were visualized through the CFD simulation. Based on these results, the relationship between the reactor performance and the hydrodynamics of EMBR was further elucidated relative to the current generation. The results of this study would benefit the design, operation and optimization of the EMBR for simultaneous energy recovery and wastewater treatment. PMID:25997399

  18. Hydrodynamics of an electrochemical membrane bioreactor.

    PubMed

    Wang, Ya-Zhou; Wang, Yun-Kun; He, Chuan-Shu; Yang, Hou-Yun; Sheng, Guo-Ping; Shen, Jin-You; Mu, Yang; Yu, Han-Qing

    2015-05-22

    An electrochemical membrane bioreactor (EMBR) has recently been developed for energy recovery and wastewater treatment. The hydrodynamics of the EMBR would significantly affect the mass transfers and reaction kinetics, exerting a pronounced effect on reactor performance. However, only scarce information is available to date. In this study, the hydrodynamic characteristics of the EMBR were investigated through various approaches. Tracer tests were adopted to generate residence time distribution curves at various hydraulic residence times, and three hydraulic models were developed to simulate the results of tracer studies. In addition, the detailed flow patterns of the EMBR were acquired from a computational fluid dynamics (CFD) simulation. Compared to the tank-in-series and axial dispersion ones, the Martin model could describe hydraulic performance of the EBMR better. CFD simulation results clearly indicated the existence of a preferential or circuitous flow in the EMBR. Moreover, the possible locations of dead zones in the EMBR were visualized through the CFD simulation. Based on these results, the relationship between the reactor performance and the hydrodynamics of EMBR was further elucidated relative to the current generation. The results of this study would benefit the design, operation and optimization of the EMBR for simultaneous energy recovery and wastewater treatment.

  19. Pilot-scale experiment on anaerobic bioreactor landfills in China

    SciTech Connect

    Jiang, Jianguo Yang, Guodong; Deng, Zhou; Huang, Yunfeng; Huang, Zhonglin; Feng, Xiangming; Zhou, Shengyong; Zhang, Chaoping

    2007-07-01

    Developing countries have begun to investigate bioreactor landfills for municipal solid waste management. This paper describes the impacts of leachate recirculation and recirculation loadings on waste stabilization, landfill gas (LFG) generation and leachate characteristics. Four simulated anaerobic columns, R1-R4, were each filled with about 30 tons of waste and recirculated weekly with 1.6, 0.8 and 0.2 m{sup 3} leachate and 0.1 m{sup 3} tap water. The results indicated that the chemical oxygen demand (COD) half-time of leachate from R1 was about 180 days, which was 8-14 weeks shorter than that of R2-R4. A large amount of LFG was first produced in R1, and its generation rate was positively correlated to the COD or volatile fatty acid concentrations of influent leachates after the 30th week. By the 50th week of recirculation, the waste in R1 was more stabilized, with 931.2 kg COD or 175.6 kg total organic carbon released and with the highest landfill gas production. However, this contributed mainly to washout by leachate, which also resulted in the reduction of LFG generation potential and accumulation of ammonia and/or phosphorus in the early stage. Therefore, the regimes of leachate recirculation should be adjusted to the phases of waste stabilization to enhance efficiency of energy recovery. Integrated with the strategy of in situ leachate management, extra pre-treatment or post-treatment methods to remove the nutrients are recommended.

  20. Sustainable operation of submerged Anammox membrane bioreactor with recycling biogas sparging for alleviating membrane fouling.

    PubMed

    Li, Ziyin; Xu, Xindi; Xu, Xiaochen; Yang, FengLin; Zhang, ShuShen

    2015-12-01

    A submerged anaerobic ammonium oxidizing (Anammox) membrane bioreactor with recycling biogas sparging for alleviating membrane fouling has been successfully operated for 100d. Based on the batch tests, a recycling biogas sparging rate at 0.2m(3)h(-1) was fixed as an ultimate value for the sustainable operation. The mixed liquor volatile suspended solid (VSS) of the inoculum for the long operation was around 3000mgL(-1). With recycling biogas sparging rate increasing stepwise from 0 to 0.2m(3)h(-1), the reactor reached an influent total nitrogen (TN) up to 1.7gL(-1), a stable TN removal efficiency of 83% and a maximum specific Anammox activity (SAA) of 0.56kg TNkg(-1) VSSd(-1). With recycling biogas sparging rate at 0.2 m(3) h(-1) (corresponding to an aeration intensity of 118m(3)m(-2)h(-1)), the membrane operation circle could prolong by around 20 times compared to that without gas sparging. Furthermore, mechanism of membrane fouling was proposed. And with recycling biogas sparging, the VSS and EPS content increasing rate in cake layer were far less than the ones without biogas sparging. The TN removal performance and sustainable membrane operation of this system showed the appealing potential of the submerged Anammox MBR with recycling biogas sparging in treating high-strength nitrogen-containing wastewaters.

  1. Sequential anaerobic and aerobic treatment of pulp and paper mill effluent in pilot scale bioreactor.

    PubMed

    Singh, Pratibha

    2007-01-01

    In the present study sequential anaerobic and aerobic treatment in two step bioreactor was performed for removal of colour in the pulp and paper mill effluent. In anaerobic treatment, colour 50%, lignin 62%, COD 29%, absordable organic halides (AOX) 25% and phenol 29% were reduced in eight days. The anaerobically treated effluent was separately applied in bioreactor in presence of fungal strain, Paecilomyces sp., and bacterial strain, Microbrevis luteum. Data of study indicated reduction in colour 80%, AOX 74%, lignin 81%, COD 93% and phenol 76 per cent by Paecilomyces sp. where as Microbrevis luteum showed removal in colour 59%, lignin 71%, COD 86%, AOX 84% and phenol 88% by day third when 7 days anaerobically treated effluent was further treated by aerobic microorganisms. Change in pH of the effluent and increase in biomass of microorganism's substantiated results of the study, which was concomitant to the treatment method.

  2. Organic ionic salt draw solutions for osmotic membrane bioreactors.

    PubMed

    Bowden, Katie S; Achilli, Andrea; Childress, Amy E

    2012-10-01

    This investigation evaluates the use of organic ionic salt solutions as draw solutions for specific use in osmotic membrane bioreactors. Also, this investigation presents a simple method for determining the diffusion coefficient of ionic salt solutions using only a characterized membrane. A selection of organic ionic draw solutions underwent a desktop screening process before being tested in the laboratory and evaluated for performance using specific salt flux (reverse salt flux per unit water flux), biodegradation potential, and replenishment cost. Two of the salts were found to have specific salt fluxes three to six times lower than two commonly used inorganic draw solutions, NaCl and MgCl(2). All of the salts tested have organic anions with the potential to degrade in the bioreactor as a carbon source and aid in nutrient removal. Results demonstrate the potential benefits of organic ionic salt draw solutions over currently implemented inorganics in osmotic membrane bioreactor systems.

  3. Membrane coagulation bioreactor (MCBR) for drinking water treatment.

    PubMed

    Tian, Jia-Yu; Liang, Heng; Li, Xing; You, Shi-jie; Tian, Sen; Li, Gui-bai

    2008-08-01

    In this paper, a novel submerged ultrafiltration (UF) membrane coagulation bioreactor (MCBR) process was evaluated for drinking water treatment at a hydraulic retention time (HRT) as short as 0.5h. The MCBR performed well not only in the elimination of particulates and microorganisms, but also in almost complete nitrification and phosphate removal. As compared to membrane bioreactor (MBR), MCBR achieved much higher removal efficiencies of organic matter in terms of total organic carbon (TOC), permanganate index (COD(Mn)), dissolved organic carbon (DOC) and UV absorbance at 254nm (UV(254)), as well as corresponding trihalomethanes formation potential (THMFP) and haloacetic acids formation potential (HAAFP), due to polyaluminium chloride (PACl) coagulation in the bioreactor. However, the reduction of biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) by MCBR was only 8.2% and 10.1% higher than that by MBR, indicating that biodegradable organic matter (BOM) was mainly removed through biodegradation. On the other hand, the trans-membrane pressure (TMP) of MCBR developed much lower than that of MBR, which implies that coagulation in the bioreactor could mitigate membrane fouling. It was also identified that the removal of organic matter was accomplished through the combination of three unit effects: rejection by UF, biodegradation by microorganism and coagulation by PACl. During filtration operation, a fouling layer was formed on the membranes surface of both MCBR and MBR, which functioned as a second membrane for further separating organic matter.

  4. Feasibility study of moving-fiber biofilm membrane bioreactor for wastewater treatment: process control.

    PubMed

    Phattaranawik, Jirachote; Leiknes, Torove

    2011-03-01

    Non-biodegradable solid wastes of non-intact membrane fibres/flatsheets and modules disposed from membrane bioreactor (MBR) plants are in a great concern for environmental impact. Estimated cumulative amount of the module solid wastes from European countries in the next five years should be larger than 1000 tons in which a proper management strategy and reuse for the disposed solid waste are urgently required. This article was aimed to propose an alternative to make uses of the non-intact membrane fibres for the aerobic biofilm supports and to study the feasibility on process operation of novel moving-fiber biofilm MBR. A system of moving-fiber biofilm membrane bioreactor was designed and evaluated experimentally, including an upflow anaerobic sludge reactor, an aerobic moving-fiber biofilm reactor, and a submerged membrane filtration unit. Start-up method and operating conditions to control the biofilms growing on the moving fibers were investigated. Organic removal rates, optimum operating conditions for the system, and membrane fouling rates at various membrane aeration rates and permeate fluxes were monitored to evaluate the performance of the proposed BF-MBR process.

  5. Treatment of phenolics, aromatic hydrocarbons, and cyanide-bearing wastewater in individual and combined anaerobic, aerobic, and anoxic bioreactors.

    PubMed

    Sharma, Naresh K; Philip, Ligy

    2015-01-01

    Studies were conducted on a mixture of pollutants commonly found in coke oven wastewater (CWW) to evaluate the biodegradation of various pollutants under anaerobic, aerobic, and anoxic conditions. The removal of the pollutants was monitored during individual bioreactor operation and using a combination of bioreactors operating in anaerobic-aerobic-anoxic sequence. While studying the performance of individual reactors, it was observed that cyanide removal (83.3 %) was predominant in the aerobic bioreactor, while much of the chemical oxygen demand (COD) (69 %) was consumed in the anoxic bioreactor. With the addition of cyanide, the COD removal efficiency was affected in all the bioreactors, and several intermediates were detected. While treating synthetic CWW using the combined bioreactor system, the overall COD removal efficiency was 86.79 % at an OLR of 2.4 g COD/L/day and an HRT of 96 h. The removal efficiency of 3,5-xylenol and cyanide, with inlet concentration of 150 and 10 mg/L, was found to be 91.8 and 93.6 % respectively. It was found that the impact of xylenol on the performance of the bioreactors was less than cyanide toxicity. Molecular analysis using T-RFLP revealed the dominance of strictly aerobic, mesophilic proteobacterium, Bosea minatitlanensis, in the aerobic bioreactor. The anoxic bioreactor was dominant with Rhodococcus pyridinivorans, known for its remarkable aromatic decomposing activity, while an unclassified Myxococcales bacterium was identified as the predominant bacterial species in the anaerobic bioreactor.

  6. Comparison and Analysis of Membrane Fouling between Flocculent Sludge Membrane Bioreactor and Granular Sludge Membrane Bioreactor

    PubMed Central

    Zhi-Qiang, Chen; Jun-Wen, Li; Yi-Hong, Zhang; Xuan, Wang; Bin, Zhang

    2012-01-01

    The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs), two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates. PMID:22859954

  7. Comparison between moving bed-membrane bioreactor (MB-MBR) and membrane bioreactor (MBR) systems: influence of wastewater salinity variation.

    PubMed

    Di Trapani, Daniele; Di Bella, Gaetano; Mannina, Giorgio; Torregrossa, Michele; Viviani, Gaspare

    2014-06-01

    Two pilot plant systems were investigated for the treatment of wastewater subject to a gradual increase of salinity. In particular, a membrane bioreactor (MBR) and a moving bed biofilm membrane bioreactor (MB-MBR) were analyzed. Carbon and ammonium removal, kinetic constants and membranes fouling rates have been assessed. Both plants showed very high efficiency in terms of carbon and ammonium removal and the gradual salinity increase led to a good acclimation of the biomass, as confirmed by the respirometric tests. Significant biofilm detachments from carriers were experienced, which contributed to increase the irreversible superficial cake deposition. However, this aspect prevented the pore fouling tendency in the membrane module of MB-MBR system. On the contrary, the MBR pilot, even showing a lower irreversible cake deposition, was characterized by a higher pore fouling tendency.

  8. Biogas Production from Citrus Waste by Membrane Bioreactor

    PubMed Central

    Wikandari, Rachma; Millati, Ria; Cahyanto, Muhammad Nur; Taherzadeh, Mohammad J.

    2014-01-01

    Rapid acidification and inhibition by d-limonene are major challenges of biogas production from citrus waste. As limonene is a hydrophobic chemical, this challenge was encountered using hydrophilic polyvinylidine difluoride (PVDF) membranes in a biogas reactor. The more sensitive methane-producing archaea were encapsulated in the membranes, while freely suspended digesting bacteria were present in the culture as well. In this membrane bioreactor (MBR), the free digesting bacteria digested the citrus wastes and produced soluble compounds, which could pass through the membrane and converted to biogas by the encapsulated cell. As a control experiment, similar digestions were carried out in bioreactors containing the identical amount of just free cells. The experiments were carried out in thermophilic conditions at 55 °C, and hydraulic retention time of 30 days. The organic loading rate (OLR) was started with 0.3 kg VS/m3/day and gradually increased to 3 kg VS/m3/day. The results show that at the highest OLR, MBR was successful to produce methane at 0.33 Nm3/kg VS, while the traditional free cell reactor reduced its methane production to 0.05 Nm3/kg VS. Approximately 73% of the theoretical methane yield was achieved using the membrane bioreactor. PMID:25167328

  9. Influence of fertilizer draw solution properties on the process performance and microbial community structure in a side-stream anaerobic fertilizer-drawn forward osmosis - ultrafiltration bioreactor.

    PubMed

    Kim, Youngjin; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

    2017-02-27

    In this study, a side-stream anaerobic fertilizer-drawn forward osmosis (FDFO) and ultrafiltration (UF) membrane bioreactor (MBR) hybrid system was proposed and operated for 55days. The FDFO performance was first investigated in terms of flux decline with various fertilizers draw solution. Flux decline was very severe with all fertilizers due to the absence of aeration and the sticky property of sludge. Flux recovery by physical cleaning varied significantly amongst tested fertilizers which seriously affected biofouling in FDFO via reverse salt flux (RSF). Besides, RSF had a significant impact on nutrient accumulation in the bioreactor. These results indicated that nutrient accumulation negatively influenced the anaerobic activity. To elucidate these phenomena, bacterial and archaeal community structures were analyzed by pyrosequencing. Results showed that bacterial community structure was affected by fertilizer properties with less impact on archaeal community structure, which resulted in a reduction in biogas production and an increase in nitrogen content.

  10. Toxicity of the effluent from an anaerobic bioreactor treating cereal residues on Lactuca sativa.

    PubMed

    Young, Brian Jonathan; Riera, Nicolás Iván; Beily, María Eugenia; Bres, Patricia Alina; Crespo, Diana Cristina; Ronco, Alicia Estela

    2012-02-01

    Effluents generated during the process of anaerobic digestion should be treated before their disposal into the environment. The aim of this study was evaluating the effectiveness of the effluent treatment system from an anaerobic bioreactor, assessing the toxicity reduction with the Lactuca sativa seed germination and root elongation inhibition test. Three sampling points were selected along the effluent treatment system: inflow into the first treatment pond, outflow from the third pond and recirculated flow to the bioreactor. Effluent dilutions tested for each sampling point were 25% and 50% (v/v), undiluted sample and controls. The pH, conductivity, temperature, dissolved oxygen, BOD₅ and COD were measured. The decrease in the organic and inorganic loads was correlated with a reduction in the phytotoxicity. The use of the seed toxicity test allows evaluating the quality and effectiveness of the studied effluent treatment system.

  11. Treatment of ammonium-rich swine waste in modified porphyritic andesite fixed-bed anaerobic bioreactor.

    PubMed

    Wang, Qinghong; Yang, Yingnan; Li, Dawei; Feng, Chuanping; Zhang, Zhenya

    2012-05-01

    In this study, a modified porphyritic andesite (WRS) was developed as ammonium adsorbent and bed material for the anaerobic digestion of ammonium-rich swine waste. The performance in bioreactors with modified WRS, natural WRS, calcium chloride and no additives was investigated. The bioreactor with modified WRS exhibited the best performance, with start-up time on the 7th day, methane yield of 359.71 ml/g-VS, and COD removal of 67.99% during all 44 days of the experiment at 35°C. The effective ammonium adsorption and essential ions dissociation for microorganisms by modified WRS, as well as the immobilization of microbial on the surface of the modified WRS play a great role on the high efficiency anaerobic digestion of ammonium-rich swine waste.

  12. Treatment of nitrate-rich water in a baffled membrane bioreactor (BMBR) employing waste derived materials.

    PubMed

    Basu, Subhankar; Singh, Saurabh K; Tewari, Prahlad K; Batra, Vidya S; Balakrishnan, Malini

    2014-12-15

    Nitrate removal in submerged membrane bioreactors (MBRs) is limited as intensive aeration (for maintaining adequate dissolved oxygen levels and for membrane scouring) deters the formation of anoxic zones essential for biological denitrification. The present study employs baffled membrane bioreactor (BMBR) to overcome this constraint. Treatment of nitrate rich water (synthetic and real groundwater) was investigated. Sludge separation was achieved using ceramic membrane filters prepared from waste sugarcane bagasse ash. A complex external carbon source (leachate from anaerobic digestion of food waste) was used to maintain an appropriate C/N ratio. Over 90% COD and 95% NO3-N reduction was obtained. The bagasse ash filters produced a clear permeate, free of suspended solids. Sludge aggregates were observed in the reactor and were linked to the high extracellular polymeric substances (EPS) content. Lower sludge volume index (40 mL/g compared to 150 mL/g for seed sludge), higher settling velocity (47 m/h compared to 10 m/h for seed sludge) and sludge aggregates (0.7 mm aggregates compared to <0.2 mm for seed sludge) was observed. The results demonstrate the potential of waste-derived materials viz. food waste leachate and bagasse ash filters in water treatment.

  13. Energy conservation and production in a packed-bed anaerobic bioreactor

    SciTech Connect

    Pit, W.W. Jr.; Genung, R.K.

    1980-01-01

    Oak Ridge National Laboratory (ORNL) is developing an energy-conserving/ producing wastewater treatment system based on a fixed-film anaerobic bioreactor. The treatment process is based on passing wastewaters upward through the bioreactor for continuous treatment by gravitational settling, biophysical filtration and biological decomposition. A two-year pilot-plant project using a bioreactor designed to treat 5000 gpd has been conducted using raw wastewater on a municipal site in Oak Ridge, Tennessee. Data obtained for the performance of the bioreactor during this project have been analyzed by ORNL and Associated Water and Air Resources Engineers (AWARE), Inc. of Nashville, Tennessee. From these analyses it was estimated that hydraulic loading rates of 0.25 gpm/ft/sup 2/ and hydraulic residence times of 10 hours could be used in designing such bioreactors for the secondary treatment of municipal wastewaters. Conceptual designs for total treatment systems processing up to one million gallons of wastewater per day were developed based on the performance of the pilot plant bioreactor. These systems were compared to activated sludge treatment systems also operating under secondary treatment requirements and were found to consume as little as 30% of the energy required by the activated sludge systems. Economic advantages of the process result from the elimination of operating energy requirements associated with the aeration of aerobic-based processes and with the significant decrease of sludge-handling costs required with conventional activated sludge treatment systems.Furthermore, methane produced by anaerobic fermentation processes occurring during the biological decomposition of carbonaceous wastes also represented a significant and recoverable energy production. For dilute municipal wastewaters this would completely offset the remaining energy required for treatment, while for concentrated industrial wastewater would result in a net production of energy.

  14. COMMERCIAL-SCALE AEROBIC-ANAEROBIC BIOREACTOR LANDFILL OPERATIONS

    EPA Science Inventory

    A sequential aerobic-anaerobic treatment system has been applied at a commercial scale (3,000 ton per day) municipal solid waste landfill in Kentucky, USA since 2001. In this system, the uppermost layer of landfilled waste is aerated and liquid waste including leachate, surface w...

  15. Sewage treatment by a low energy membrane bioreactor.

    PubMed

    Zhang, Shaoyuan; van Houten, Renze; Eikelboom, Dick H; Doddema, Hans; Jiang, Zhaochun; Fan, Yaobo; Wang, Jusi

    2003-11-01

    A new membrane bioreactor (MBR) was developed for treatment of municipal wastewater. The MBR was mainly made up of an activated sludge reactor and a transverse flow membrane module, with an innovative configuration being in application between them. As a result, the transverse flow membrane module and low recirculation flow rate created advantages, such as lower energy consumption and more resistance to membrane fouling. The total energy consumption in the whole system was tested as 1.97+/-0.74 kWh/m(3) (permeate) while using periodical backwash with treated water and backflush with mixed liquor daily, being in the same level as a submerged membrane bioreactor, reported to be 2.4 kWh/m(3) (permeate). Energy consumption analysis in the system shows that the membrane module was more energy consuming than the other four parts listed as pump, aeration, pipe system and return sludge velocity lose, which consumed 37.66-52.20% of the total energy. The effluent from this system could be considered as qualified for greywater reuse in China, showing its potential application in the future.

  16. Electrolysis within anaerobic bioreactors stimulates breakdown of toxic products from azo dye treatment.

    PubMed

    Gavazza, Sávia; Guzman, Juan J L; Angenent, Largus T

    2015-04-01

    Azo dyes are the most widely used coloring agents in the textile industry, but are difficult to treat. When textile effluents are discharged into waterways, azo dyes and their degradation products are known to be environmentally toxic. An electrochemical system consisting of a graphite-plate anode and a stainless-steel mesh cathode was placed into a lab-scale anaerobic bioreactor to evaluate the removal of an azo dye (Direct Black 22) from synthetic textile wastewater. At applied potentials of 2.5 and 3.0 V when water electrolysis occurs, no improvement in azo dye removal efficiency was observed compared to the control reactor (an integrated system with electrodes but without an applied potential). However, applying such electric potentials produces oxygen via electrolysis and promoted the aerobic degradation of aromatic amines, which are toxic, intermediate products of anaerobic azo dye degradation. The removal of these amines indicates a decrease in overall toxicity of the effluent from a single-stage anaerobic bioreactor, which warrants further optimization in anaerobic digestion.

  17. A new neural observer for an anaerobic bioreactor.

    PubMed

    Belmonte-Izquierdo, R; Carlos-Hernandez, S; Sanchez, E N

    2010-02-01

    In this paper, a recurrent high order neural observer (RHONO) for anaerobic processes is proposed. The main objective is to estimate variables of methanogenesis: biomass, substrate and inorganic carbon in a completely stirred tank reactor (CSTR). The recurrent high order neural network (RHONN) structure is based on the hyperbolic tangent as activation function. The learning algorithm is based on an extended Kalman filter (EKF). The applicability of the proposed scheme is illustrated via simulation. A validation using real data from a lab scale process is included. Thus, this observer can be successfully implemented for control purposes.

  18. Biofouling control: Bacterial quorum quenching versus chlorination in membrane bioreactors.

    PubMed

    Weerasekara, Nuwan A; Choo, Kwang-Ho; Lee, Chung-Hak

    2016-10-15

    Biofilm formation (biofouling) induced via cell-to-cell communication (quorum sensing) causes problems in membrane filtration processes. Chorine is one of the most common chemicals used to interfere with biofouling; however, biofouling control is challenging because it is a natural process. This study demonstrates biofouling control for submerged hollow fiber membranes in membrane bioreactors by means of bacterial quorum quenching (QQ) using Rhodococcus sp. BH4 with chemically enhanced backwashing. This is the first trial to bring QQ alongside chlorine injection into practice. A high chlorine dose (100 mg/L as Cl2) to the system is insufficient for preventing biofouling, but addition of the QQ bacterium is effective for disrupting biofouling that cannot be achieved by chlorination alone. QQ reduces the biologically induced metal precipitate and extracellular biopolymer levels in the biofilm, and biofouling is significantly delayed when QQ is applied in addition to chlorine dosing. QQ with chlorine injection gives synergistic effects on reducing physically and chemically reversible fouling resistances while saving substantial filtration energy. Manipulating microbial community functions with chemical treatment is an attractive tool for biofilm dispersal in membrane bioreactors.

  19. The innovative osmotic membrane bioreactor (OMBR) for reuse of wastewater.

    PubMed

    Cornelissen, E R; Harmsen, D; Beerendonk, E F; Qin, J J; Oo, H; de Korte, K F; Kappelhof, J W M N

    2011-01-01

    An innovative osmotic membrane bioreactor (OMBR) is currently under development for the reclamation of wastewater, which combines activated sludge treatment and forward osmosis (FO) membrane separation with a RO post-treatment. The research focus is FO membrane fouling and performance using different activated sludge investigated both at laboratory scale (membrane area of 112cm2) and at on-site bench scale (flat sheet membrane area of 0.1 m2). FO performance on laboratory-scale (i) increased with temperature due to a decrease in viscosity and (ii) was independent of the type of activated sludge. Draw solution leakage increased with temperature and varied for different activated sludge. FO performance on bench-scale (i) increased with osmotic driving force, (ii) depended on the membrane orientation due to internal concentration polarization and (iii) was invariant to feed flow decrease and air injection at the feed and draw side. Draw solution leakage could not be evaluated on bench-scale due to experimental limitation. Membrane fouling was not found on laboratory scale and bench-scale, however, partially reversible fouling was found on laboratory scale for FO membranes facing the draw solution. Economic assessment indicated a minimum flux of 15L.m-2 h-1 at 0.5M NaCl for OMBR-RO to be cost effective, depending on the FO membrane price.

  20. Trace organics removal using three membrane bioreactor configurations: MBR, IFAS-MBR and MBMBR.

    PubMed

    de la Torre, T; Alonso, E; Santos, J L; Rodríguez, C; Gómez, M A; Malfeito, J J

    2015-01-01

    Seventeen pharmaceutically active compounds and 22 other trace organic pollutants were analysed regularly in the influent and permeate from a semi-real plant treating municipal wastewater. The plant was operated during 29 months with different configurations which basically differed in the type of biomass present in the system. These processes were the integrated fixed-film activated sludge membrane bioreactor (IFAS-MBR), which combined suspended and attached biomass, the moving bed membrane bioreactor (MBMBR) (only attached biomass) and the MBR (only suspended biomass). Moreover, removal rates were compared to those of the wastewater treatment plant (WWTP) operating nearby with conventional activated sludge treatment. Reverse osmosis (RO) was used after the pilot plant to improve removal rates. The highest elimination was found for the IFAS-MBR, especially for hormones (100% removal); this was attributed to the presence of biofilm, which may lead to different conditions (aerobic-anoxic-anaerobic) along its profile, which increases the degradation possibilities, and also to a higher sludge age of the biofilm, which allows complete acclimation to the contaminants. Operating conditions played an important role, high mixed liquor suspended solids (MLSS) and sludge retention time (SRT) being necessary to achieve these high removal rates. Although pharmaceuticals and linear alkylbenzene sulfonates showed high removal rates (65-100%), nonylphenols and phthalate could only be removed to 10-30%. RO significantly increased removal rates to 88% mean removal rate.

  1. Simulation of municipal solid waste degradation in aerobic and anaerobic bioreactor landfills.

    PubMed

    Patil, Bhagwan Shamrao; C, Agnes Anto; Singh, Devendra Narain

    2017-03-01

    Municipal solid waste generation is huge in growing cities of developing nations such as India, owing to the rapid industrial and population growth. In addition to various methods for treatment and disposal of municipal solid waste (landfills, composting, bio-methanation, incineration and pyrolysis), aerobic/anaerobic bioreactor landfills are gaining popularity for economical and effective disposal of municipal solid waste. However, efficiency of municipal solid waste bioreactor landfills primarily depends on the municipal solid waste decomposition rate, which can be accelerated through monitoring moisture content and temperature by using the frequency domain reflectometry probe and thermocouples, respectively. The present study demonstrates that these landfill physical properties of the heterogeneous municipal solid waste mass can be monitored using these instruments, which facilitates proper scheduling of the leachate recirculation for accelerating the decomposition rate of municipal solid waste.

  2. Comparison of treatment efficiency of submerged nanofiltration membrane bioreactors using cellulose triacetate and polyamide membrane.

    PubMed

    Choi, J H; Fukushi, K; Yamamoto, K

    2005-01-01

    This study evaluates the performance of nanofiltration membrane bioreactor (NF MBR) systems using cellulose triacetate (CA) and polyamide (PA) membranes. The results indicated that both NF membranes could produce high quality permeate in the submerged NF MBR system. In addition, hollow fiber CA membranes exhibited the capability of higher permeate productivity than PA membranes. However, to obtain high quality permeate for a long-term operation, CA membranes should be maintained using an appropriate method, such as chlorine disinfection, in order to control the membrane biodegradation. The results demonstrated that PA membranes were capable of producing higher quality permeate for a long period than CA membranes. In order to enhance the practicability of PA membranes in submerged NF MBR systems, it is required that the membranes should have the lowest possible intrinsic salt rejection.

  3. Fouling mechanisms of gel layer in a submerged membrane bioreactor.

    PubMed

    Hong, Huachang; Zhang, Meijia; He, Yiming; Chen, Jianrong; Lin, Hongjun

    2014-08-01

    The fouling mechanisms underlying gel layer formation and its filtration resistance in a submerged membrane bioreactor (MBR) were investigated. It was found that gel layer rather than cake layer was more easily formed when soluble microbial products content in sludge suspension was relatively high. Thermodynamic analyses showed that gel layer formation process should overcome a higher energy barrier as compared with cake layer formation process. However, when separation distance <2.3 nm, attractive interaction energy of gelling foulant-membrane combination was remarkably higher than that of sludge floc-membrane combination. The combined effects were responsible for gel layer formation. Filtration tests showed that specific filtration resistance (SFR) of gel layer was almost 100 times higher than that of cake layer. The unusually high SFR of gel layer could be ascribed to the gelling propensity and osmotic pressure mechanism. These findings shed significant light on fouling mechanisms of gel layer in MBRs.

  4. Osmotic membrane bioreactor for phenol biodegradation under continuous operation.

    PubMed

    Praveen, Prashant; Loh, Kai-Chee

    2016-03-15

    Continuous phenol biodegradation was accomplished in a two-phase partitioning osmotic membrane bioreactor (TPPOMBR) system, using extractant impregnated membranes (EIM) as the partitioning phase. The EIMs alleviated substrate inhibition during prolonged operation at influent phenol concentrations of 600-2000mg/L, and also at spiked concentrations of 2500mg/L phenol restricted to 2 days. Filtration of the effluent through forward osmosis maintained high biomass concentration in the bioreactor and improved effluent quality. Steady state was reached in 5-6 days at removal rates varying between 2000 and 5500mg/L-day under various conditions. Due to biofouling and salt accumulation, the permeate flux varied from 1.2-7.2 LMH during 54 days of operation, while maintaining an average hydraulic retention time of 7.4h. A washing cycle, comprising 1h osmotic backwashing using 0.5M NaCl and 2h washing with water, facilitated biofilm removal from the membranes. Characterization of the extracellular polymeric substances (EPS) through FTIR showed peaks between 1700 and 1500cm(-1), 1450-1450cm(-1) and 1200-1000cm(-1), indicating the presence of proteins, phenols and polysaccharides, respectively. The carbohydrate to protein ratio in the EPS was estimated to be 0.3. These results indicate that TPPOMBR can be promising in continuous treatment of phenolic wastewater.

  5. Startup of the Anammox Process in a Membrane Bioreactor (AnMBR) from Conventional Activated Sludge.

    PubMed

    Gutwiński, P; Cema, G; Ziembińska-Buczyńska, A; Surmacz-Górska, J; Osadnik, M

    2016-12-01

      In this study, a laboratory-scale anammox process in a membrane bioreactor (AnMBR) was used to startup the anaerobic ammonium oxidation (anammox) process from conventional activated sludge. Stable operation was achieved after 125 days. From that time, nitrogen load was gradually increased. After six months, the average nitrogen removal efficiency exceeded 80%. The highest obtained special anammox activity (SAA) achieved was 0.17 g (-N + -N) (g VSS × d)-1. Fluorescent in situ hybridization also proved the presence of the anammox bacteria, typically a genus of Brocadia anammoxidans and Kuenenia stuttgartiensis.

  6. Start-up of the Anammox process from the conventional activated sludge in a membrane bioreactor.

    PubMed

    Wang, Tao; Zhang, Hanmin; Yang, Fenglin; Liu, Sitong; Fu, Zhimin; Chen, Huihui

    2009-05-01

    A lab-scale membrane bioreactor (MBR) was used to start-up the anaerobic ammonium oxidation (Anammox) process from the conventional activated sludge for 2 months. Results indicated the MBR could be a novel and suitable system for start-up of the Anammox process. The Anammox activity appeared after 16 days operation, and the average removal efficiencies of ammonia and nitrite were both over 90% in the end. A final specific Anammox activity of 0.35 g NH(4)(+)-N+NO(2)(-)-N (gVSS *d)(-1) was obtained. Fluorescence in situ hybridization (FISH) analysis confirmed the existence of Anammox bacteria and aerobic ammonia oxidizing bacteria. On the basis of results on MBR performance and FISH analysis, it was proposed that the start-up process was essentially a microbial community succession under man-made disturbance, and a climax community with Anammox bacteria as the dominant population was finally established.

  7. Mitigated membrane fouling of anammox membrane bioreactor by microbiological immobilization.

    PubMed

    Zhang, Zuotao; Liu, Sitong; Miyoshi, Taro; Matsuyama, Hideto; Ni, Jinren

    2016-02-01

    In this study, membrane fouling behavior of anammox MBR with or without carriers made by magnetic porous carbon microspheres was investigated. The results show that Trans Membrane Pressure was an order of magnitude lower after 50days due to use of carriers, which did not directly contact with membrane surface. Scanning Electron Microscope analysis indicates that abundance of anammox bacteria formed biofilm on membrane surface. Fourier transform infrared spectroscopy combined with amino acids contents analysis for membrane surface deposition show that metabolite released by anammox bacteria contains more hydrophobic groups than hydrophilic, which was considered as important reason for its abundant existence on hydrophobic membrane surface. Microbiological immobilization not only reduces biological membrane fouling, but also mitigates organic fouling including organic matter containing COO, hydrophobic groups (CH3, CH2 and CH etc), as well as inorganic deposition. Our finding provides an effective method for mitigating MBR membrane fouling in anammox process.

  8. Enhanced Biogas Production from Nanoscale Zero Valent Iron-Amended Anaerobic Bioreactors.

    PubMed

    Carpenter, Alexis Wells; Laughton, Stephanie N; Wiesner, Mark R

    2015-08-01

    Addition of nanoscale zero valent iron (NZVI) to anaerobic batch reactors to enhance methanogenic activity is described. Two NZVI systems were tested: a commercially available NZVI (cNZVI) slurry and a freshly synthesized NZVI (sNZVI) suspension that was prepared immediately before addition to the reactors. In both systems, the addition of NZVI increased pH and decreased oxidation/reduction potential compared with unamended control reactors. Biodegradation of a model brewery wastewater was enhanced as indicated by an increase in chemical oxygen demand removal with both sNZVI and cNZVI amendments at all concentrations tested (1.25-5.0 g Fe/L). Methane production increased for all NZVI-amended bioreactors, with a maximum increase of 28% achieved on the addition of 2.5 and 5.0 g/L cNZVI. Addition of bulk zero-valent iron resulted in only a 5% increase in methane, indicating the advantage of using the nanoscale particles. NZVI amendments further improved produced biogas by decreasing the amount of CO2 released from the bioreactor by approximately 58%. Overall, addition of cNZVI proved more beneficial than the sNZVI at equal iron concentrations, due to decreased colloidal stability and larger effective particle size of sNZVI. Although some have reported cytotoxicity of NZVI to anaerobic microorganisms, work presented here suggests that NZVI of a certain particle size and reactivity can serve as an amendment to anaerobic digesters to enhance degradation and increase the value of the produced biogas, yielding a more energy-efficient anaerobic method for wastewater treatment.

  9. Enhanced Biogas Production from Nanoscale Zero Valent Iron-Amended Anaerobic Bioreactors

    PubMed Central

    Carpenter, Alexis Wells; Laughton, Stephanie N.; Wiesner, Mark R.

    2015-01-01

    Abstract Addition of nanoscale zero valent iron (NZVI) to anaerobic batch reactors to enhance methanogenic activity is described. Two NZVI systems were tested: a commercially available NZVI (cNZVI) slurry and a freshly synthesized NZVI (sNZVI) suspension that was prepared immediately before addition to the reactors. In both systems, the addition of NZVI increased pH and decreased oxidation/reduction potential compared with unamended control reactors. Biodegradation of a model brewery wastewater was enhanced as indicated by an increase in chemical oxygen demand removal with both sNZVI and cNZVI amendments at all concentrations tested (1.25–5.0 g Fe/L). Methane production increased for all NZVI-amended bioreactors, with a maximum increase of 28% achieved on the addition of 2.5 and 5.0 g/L cNZVI. Addition of bulk zero-valent iron resulted in only a 5% increase in methane, indicating the advantage of using the nanoscale particles. NZVI amendments further improved produced biogas by decreasing the amount of CO2 released from the bioreactor by approximately 58%. Overall, addition of cNZVI proved more beneficial than the sNZVI at equal iron concentrations, due to decreased colloidal stability and larger effective particle size of sNZVI. Although some have reported cytotoxicity of NZVI to anaerobic microorganisms, work presented here suggests that NZVI of a certain particle size and reactivity can serve as an amendment to anaerobic digesters to enhance degradation and increase the value of the produced biogas, yielding a more energy-efficient anaerobic method for wastewater treatment. PMID:26339183

  10. Membrane bioreactors and their uses in wastewater treatments.

    PubMed

    Le-Clech, Pierre

    2010-12-01

    With the current need for more efficient and reliable processes for municipal and industrial wastewaters treatment, membrane bioreactor (MBR) technology has received considerable attention. After just a couple of decades of existence, MBR can now be considered as an established wastewater treatment system, competing directly with conventional processes like activated sludge treatment plant. However, MBR processes still suffer from major drawbacks, including high operational costs due to the use of anti-fouling strategies applied to the system to maintain sustainable filtration conditions. Moreover, this specific use of membranes has not reached full maturity yet, as MBR suppliers and users still lack experience regarding the long-term performances of the system. Still, major improvements of the MBR design and operation have been witnessed over the recent years, making MBR an option of choice for wastewater treatment and reuse. This mini-review reports recent developments and current research trends in the field.

  11. Performance of an anaerobic, static bed, fixed film bioreactor for chlorinated solvent treatment

    USGS Publications Warehouse

    Lorah, Michelle M.; Walker, Charles; Graves, Duane

    2015-01-01

    Anaerobic, fixed film, bioreactors bioaugmented with a dechlorinating microbial consortium were evaluated as a potential technology for cost effective, sustainable, and reliable treatment of mixed chlorinated ethanes and ethenes in groundwater from a large groundwater recovery system. Bench- and pilot-scale testing at about 3 and 13,500 L, respectively, demonstrated that total chlorinated solvent removal to less than the permitted discharge limit of 100 μg/L. Various planned and unexpected upsets, interruptions, and changes demonstrated the robustness and reliability of the bioreactor system, which handled the operational variations with no observable change in performance. Key operating parameters included an adequately long hydraulic retention time for the surface area, a constant supply of electron donor, pH control with a buffer to minimize pH variance, an oxidation reduction potential of approximately −200 millivolts or lower, and a well-adapted biomass capable of degrading the full suite of chlorinated solvents in the groundwater. Results indicated that the current discharge criteria can be met using a bioreactor technology that is less complex and has less downtime than the sorption based technology currently being used to treat the groundwater.

  12. Novel filtration mode for fouling limitation in membrane bioreactors.

    PubMed

    Wu, Jinling; Le-Clech, Pierre; Stuetz, Richard M; Fane, Anthony G; Chen, Vicki

    2008-08-01

    A novel filtration mode is presented to reduce fouling propensity in membrane bioreactors (MBR). During this mode, an elevated high instantaneous flux (60Lm(-2)h(-1)) is initially applied for a short time (120s), followed by a longer filtration (290s) at lower flux (10.3Lm(-2)h(-1)) and a backwash in each filtration cycle. The mixed mode is expected to limit irreversible fouling as the reversible fouling created during the initial stage appears to protect the membrane. Hydraulic performance and the components of foulants were analyzed and compared with conventional continuous and backwash modes. It was found that the mixed mode featured lower trans-membrane pressure (TMP) after 24h of filtration when compared to other modes. The mixed mode was effective in preventing soluble microbial products (SMP) attaching directly onto the membrane surface, keeping the cake layer weakly compressed, and reducing the mixed liquor suspended solids (MLSS) accumulation on the membrane. This strategy reduced the resistances of both the cake layer and the gel layer. A factorial experimental design was carried out for eight runs with different conditions to identify the major operational parameters affecting the hydraulic performances. The results showed that the value of the flux in the initial high-flux period had the most effect on the performance of the mixed mode: high initial flux (60Lm(-2)h(-1)) led to improved performance.

  13. A review of fouling of membrane bioreactors in sewage treatment.

    PubMed

    Judd, S

    2004-01-01

    Fouling in membrane bioreactors (MBRs) represents one of the most significant barriers to their more widespread implementation for both municipal and industrial wastewater treatment. It exerts a limit on the membrane permeability, i.e. the flux through the membrane per unit transmembrane pressure, and thus the productivity of the process per unit membrane area installed. As with all membrane processes, extensive investigation of factors contributing to fouling in MBRs, and the subsequent identification of ameliorative measures that may be taken to control it, has taken place since the process was first commercialised 30 years ago. Key findings of pertinent research in this area and operational experience in full-scale plants are summarised, along with the primary facets of the MBR process itself. The most recent evidence suggests that permanent fouling, i.e. fouling not substantially removed by physical cleaning (backflushing), results mainly from certain dissolved or colloidal organic materials, and such adsoptive fouling takes place at even the lowest operational fluxes. Fouling by suspended solids, on the other hand, may be largely controlled by operation below the so-called "critical" flux, which may be increased by more vigorous aeration, and/or by periodic backflushing. It is concluded that more work is required on characterisation of species responsible for permanent fouling.

  14. Modular operation of membrane bioreactors for higher hydraulic capacity utilisation.

    PubMed

    Veltmann, K; Palmowski, L M; Pinnekamp, J

    2011-01-01

    Using data from 6 full-scale municipal membrane bioreactors (MBR) in Germany the hydraulic capacity utilisation and specific energy consumption were studied and their connexion shown. The average hydraulic capacity utilisation lies between 14% and 45%. These low values are justified by the necessity to deal with intense rain events and cater for future flow increases. However, this low hydraulic capacity utilisation leads to high specific energy consumption. The optimisation of MBR operation requires a better utilisation of MBR hydraulic capacity, particularly under consideration of the energy-intensive membrane aeration. A first approach to respond to large influent flow fluctuations consists in adjusting the number of operating modules. This is practised by most MBR operators but so far mostly with variable flux and constant membrane aeration. A second approach is the real-time adjustment of membrane aeration in line with flux variations. This adjustment is not permitted under current manufacturers' warranty conditions. A further opportunity is a discontinuous operation, in which filtration takes place over short periods at high flux and energy for membrane aeration is saved during filtration pauses. The integration of a buffer volume is thereby indispensable. Overall a modular design with small units, which can be activated/ inactivated according to the influent flow and always operate under optimum conditions, enables a better utilisation of MBR hydraulic capacity and forms a solid base to reduce MBR energy demand.

  15. A typical flat-panel membrane bioreactor with a composite membrane for sulfur removal

    NASA Astrophysics Data System (ADS)

    Guan, Jian; Xiao, Yuan; Song, Jimin; Miao, Junhe

    2014-03-01

    The aim of this work was to provide a concrete study to understand the effects of operation on biofilm morphology and microstructure and degradation efficiency for the disposal of sulfur dioxide produced by coal-fired power plants. For this purpose, a flat-panel reactor-membrane bioreactor (MBR) with a composite membrane consisting of a dense layer and a support layer was designed; the membrane bioreactors inoculated with Thiobacillus ferrooxidans were further conducted for the removal of sulfur dioxide. Dry weight, active biomass, pressure drop, removal efficiency, morphology and structure of the formed biofilms were investigated and analyzed over period of biofilm formation. The results found that the dry weight, biomass, pressure drops and removal efficiency increased rapidly during biofilm formation, remained relatively stable in the stabilization period of biofilm growth, and finally reached 0.085 g, 7.00 μg, 180 Pa, and 78%, respectively. Our results suggested the MBR is available for flue-gas desulfurization.

  16. Evaluation of membrane bioreactor process capabilities to meet stringent effluent nutrient discharge requirements.

    PubMed

    Fleischer, Edwin J; Broderick, Thomas A; Daigger, Glen T; Fonseca, Anabela D; Holbrook, R David; Murthy, Sudhir N

    2005-01-01

    A six-stage membrane bioreactor (MBR) pilot plant was operated to determine and demonstrate the capability of this process to produce a low-nutrient effluent, consistent with the nutrient reduction goals for the Chesapeake Bay. Biological nitrogen removal was accomplished using a multistage configuration with an initial anoxic zone (using the carbon in the influent wastewater), an aerobic zone (where nitrification occurred), a downstream anoxic zone (where methanol was added as a carbon source), and the aerated submerged membrane zone. The capability to reliably reduce effluent total nitrogen to less than 3 mg/L as nitrogen (N) was demonstrated. A combination of biological (using an initial anaerobic zone) and chemical (using alum) phosphorus removal was used to achieve effluent total phosphate concentrations reliably less than 0.1 mg/L as phosphorus (P) and as low as 0.03 mg/L as P. Alum addition also appeared to enhance the filtration characteristics of the MBR sludge and to reduce membrane fouling. Aeration of the submerged membranes results in thickened sludge with a high dissolved oxygen concentration (approaching saturation), which can be recycled to the main aeration zone rather than to an anoxic or anaerobic zone to optimize biological nutrient removal. Biological nutrient removal was characterized using the International Water Association Activated Sludge Model No. 2d. The stoichiometry of chemical phosphorus removal was also consistent with conventional theory and experience. The characteristics of the solids produced in the MBR were compared with those of a parallel full-scale conventional biological nitrogen removal process and were generally found to be similar. These results provide valuable insight to the design and operating characteristics of MBRs intended to produce effluents with very low nutrient concentrations.

  17. Heavy metal removal from synthetic wastewaters in an anaerobic bioreactor using stillage from ethanol distilleries as a carbon source.

    PubMed

    Gonçalves, M M M; da Costa, A C A; Leite, S G F; Sant'Anna, G L

    2007-11-01

    This work was conducted to investigate the possibility of using stillage from ethanol distilleries as substrate for sulfate reducing bacteria (SRB) growth and to evaluate the removal efficiency of heavy metals present in wastewaters containing sulfates. The experiments were carried out in a continuous bench-scale Upflow Anaerobic Sludge Blanket reactor (13 l) operated with a hydraulic retention time of 18 h. The bioreactor was inoculated with 7 l of anaerobic sludge. Afterwards, an enrichment procedure to increase SRB numbers was started. After this, cadmium and zinc were added to the synthetic wastewater, and their removal as metal sulfide was evaluated. The synthetic wastewater used represented the drainage from a dam of a metallurgical industry to which a carbon source (stillage) was added. The results showed that high percentages of removal (>99%) of Cd and Zn were attained in the bioreactor, and that the removal as sulfide precipitates was not the only form of metal removal occurring in the bioreactor environment.

  18. Thiosulphate conversion in a methane and acetate fed membrane bioreactor.

    PubMed

    Suarez-Zuluaga, Diego A; Timmers, Peer H A; Plugge, Caroline M; Stams, Alfons J M; Buisman, Cees J N; Weijma, Jan

    2016-02-01

    The use of methane and acetate as electron donors for biological reduction of thiosulphate in a 5-L laboratory membrane bioreactor was studied and compared to disproportionation of thiosulphate as competing biological reaction. The reactor was operated for 454 days in semi-batch mode; 30 % of its liquid phase was removed and periodically replenished (days 77, 119, 166, 258, 312 and 385). Although the reactor was operated under conditions favourable to promote thiosulphate reduction coupled to methane oxidation, thiosulphate disproportionation was the dominant microbial process. Pyrosequencing analysis showed that the most abundant microorganisms in the bioreactor were phototrophic green sulphur bacteria (GSB) belonging to the family Chlorobiaceae and thiosulphate-disproportionating bacteria belonging to the genus Desulfocapsa. Even though the reactor system was surrounded with opaque plastic capable of filtering most of the light, the GSB used it to oxidize the hydrogen sulphide produced from thiosulphate disproportionation to elemental sulphur. Interrupting methane and acetate supply did not have any effect on the microbial processes taking place. The ultimate goal of our research was to develop a process that could be applied for thiosulphate and sulphate removal and biogenic sulphide formation for metal precipitation. Even though the system achieved in this study did not accomplish the targeted conversion using methane as electron donor, it does perform microbial conversions which allow to directly obtain elemental sulphur from thiosulphate.

  19. Forward osmosis membrane bioreactor for wastewater treatment with phosphorus recovery.

    PubMed

    Huang, Li-Ying; Lee, Duu-Jong; Lai, Juin-Yih

    2015-12-01

    A forward osmosis membrane bioreactor (OMBR) with a thin film composite membrane was seeded with flocculated sludge and aerobic granules to treat a synthetic wastewater with 1M NaCl as draw solution. The tested OMBR showed 96%, 43% and 100% removal of PO4(3-)-P, NH4(+)-N, and total organic carbon. Salinity was accumulated in OMBR principally owing to membrane rejection and salt leakage from draw solution. At high salinity level membrane fouling could be induced. Intermittent withdrawal and replenishment of supernatant from OMBR maintained its operation stability, while phosphorus in withdrawn supernatant was recovered by pH adjustment. The OMBR enriched phosphorus concentration from 156 mg/L in feed solution to 890-990 mg/L. At pH 8.5 with 2.65-2.71 g 3 M NaOH/g-P, 814-817 mg-P/L was recovered in the form of sodium hydrogen phosphite hydrate. The OMBR is a volatile wastewater treatment unit with capability for enrichment and recovery of phosphorus at reduced chemical costs.

  20. Biofouling behavior and performance of forward osmosis membranes with bioinspired surface modification in osmotic membrane bioreactor.

    PubMed

    Li, Fang; Cheng, Qianxun; Tian, Qing; Yang, Bo; Chen, Qianyuan

    2016-07-01

    Forward osmosis (FO) has received considerable interest for water and energy related applications in recent years. Biofouling behavior and performance of cellulose triacetate (CTA) forward osmosis membranes with bioinspired surface modification via polydopamine (PD) coating and poly (ethylene glycol) (PEG) grafting (PD-g-PEG) in a submerged osmotic membrane bioreactor (OMBR) were investigated in this work. The modified membranes exhibited lower flux decline than the pristine one in OMBR, confirming that the bioinspired surface modification improved the antifouling ability of the CTA FO membrane. The result showed that the decline of membrane flux related to the increase of the salinity and MLSS concentration of the mixed liquid. It was concluded that the antifouling ability of modified membranes ascribed to the change of surface morphology in addition to the improvement of membrane hydrophilicity. The bioinspired surface modifications might improve the anti-adhesion for the biopolymers and biocake.

  1. Effect of filtration flux on the development and operation of a dynamic membrane for anaerobic wastewater treatment.

    PubMed

    Saleem, Mubashir; Alibardi, Luca; Lavagnolo, Maria Cristina; Cossu, Raffaello; Spagni, Alessandro

    2016-09-15

    Dynamic membrane represents a cost effective alternative to conventional membranes by employing fouling as a means of solid-liquid separation. This study evaluated the effects of initial flux on both development rate of dynamic membrane and bioreactor performance during two consecutive experiments. The dynamic membrane was developed over a 200 μm mesh and the reactor was operated under anaerobic conditions. It was found that the effect of an initial higher applied flux on dynamic membrane development was more pronounced than mixed liquor suspended solid concentration inside the bioreactor. The development of the dynamic membrane was therefore positively associated with the applied flux. The rapid development of the dynamic membrane during the second experimental run at high initial fluxes and lower MLSS concentrations also affected the performance of the bioreactor in terms of more efficient COD removal and biogas production. A major shortcoming of applying higher initial applied flux was the formation of a denser and robust dynamic membrane layer that was resistant to applied hydraulic shear to control desired permeability and thus represented an obstacle in maintaining a long term operation with sustainable flux at lower transmembrane pressure (TMP).

  2. Bioreactor

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues currently being cultured in rotating bioreactors by investigators

  3. Influence of membrane properties on physically reversible and irreversible fouling in membrane bioreactors.

    PubMed

    Tsuyuhara, T; Hanamoto, Y; Miyoshi, T; Kimura, K; Watanabe, Y

    2010-01-01

    This study aimed to examine the impact of membrane properties on membrane fouling in membrane bioreactor (MBR). Membrane fouling was divided into two categories: physically reversible and irreversible fouling. Membrane properties related to each type of membrane fouling were investigated separately. Five microfiltration (MF) and one ultrafiltration (UF) membranes with different properties (pore size, contact angle, roughness, zeta potential, and pure water permeability) were examined with a laboratory-scale MBR, fed with synthetic wastewater. Two separate experiments were conducted: the first to examine physically reversible fouling, and the second to examine physically irreversible fouling. The correlation between the degree of each type of fouling and membrane properties was studied. High correlation was observed between the degree of physically reversible fouling and roughness (R(2)=0.96). In contrast, with regard to physically irreversible fouling, strong correlation between roughness and degree of membrane fouling can only be found in the case of MF membranes. Except for the membrane with the highest roughness, the degree of physically irreversible fouling can be well correlated with pure water permeability (lower pure water permeability results in higher degree of physically irreversible fouling) including UF membrane. On the basis of the results obtained in this study, it can be concluded that roughness is an important factor in determination of physically reversible fouling regardless of the types of membrane (i.e. MF or UF membranes) and evolutions of physically irreversible fouling can be mitigated when an MBR is operated with membranes with smooth surface and high pure water permeability.

  4. Development and permeability of a dynamic membrane for anaerobic wastewater treatment.

    PubMed

    Alibardi, Luca; Cossu, Raffaello; Saleem, Mubashir; Spagni, Alessandro

    2014-06-01

    Dynamic membranes (DMs) have recently been proposed as an alternative to microfiltration and ultrafiltration in membrane bioreactors (MBRs) in order to contain capital and management costs. This study aims to develop an anaerobic dynamic MBR for wastewater treatment by using a large pore-sized mesh. The study demonstrated that a DM can be developed by using a mesh of 200μm pore-size and applying low cross flow velocity. The bench-scale reactor achieved COD removal efficiency between 65% and 92% and proved to be able to remove approximately 99% of the mixed liquor suspended solids, maintaining a solids retention time well above 200d. A significant quantity of biogas was produced by the external dynamic membrane module and was released with the effluent stream. The flux-step experiment, designed to estimate the critical flux in ultrafiltration MBR, can also be used for monitoring the development and stability of DMs.

  5. Treatment of toilet wastewater for reuse in a membrane bioreactor.

    PubMed

    Boehler, M; Joss, A; Buetzer, S; Holzapfel, M; Mooser, H; Siegrist, H

    2007-01-01

    Toilet wastewater is treated and reused on site at Europe's highest membrane bioreactor (MBR), located in a cable car mountain station in the ski resort of Zermatt. Negative impacts on the sensitive mountain environment are minimised by reusing close to 100% of the treated wastewater for toilet flushing. Besides 100% nitrogen removal, 80% of phosphorus was also eliminated. This paper presents operational results, optimisations of sludge management, decoloration and long-term maintenance of biomass in the very low-loaded summer season. From a global view the experiences and results of the project are of great importance, proposing a solution to a problem existing 100-fold in the Alps as well as in arid regions all over the world: reducing water consumption for sanitation by reuse.

  6. Oxygen transfer in membrane bioreactors treating synthetic greywater.

    PubMed

    Henkel, Jochen; Lemac, Mladen; Wagner, Martin; Cornel, Peter

    2009-04-01

    Mass transfer coefficients (k(L)a) were studied in two pilot scale membrane bioreactors (MBR) with different setup configurations treating 200L/h of synthetic greywater with mixed liquor suspended solids' (MLSS) concentrations ranging from 4.7 to 19.5g/L. Besides the MLSS concentration, mixed liquor volatile suspended solids (MLVSS), total solids (TS), volatile solids (VS), chemical oxygen demand (COD) and anionic surfactants of the sludge were measured. Although the pilot plants differed essentially in their configurations and aeration systems, similar alpha-factors at the same MLSS concentration could be determined. A comparison of the results to the published values of other authors showed that not the MLSS concentration but rather the MLVSS concentration seems to be the decisive parameter which influences the oxygen transfer in activated sludge systems operating at a high sludge retention time (SRT).

  7. Lactic acid fermentation in cell-recycle membrane bioreactor.

    PubMed

    Choudhury, B; Swaminathan, T

    2006-02-01

    Traditional lactic acid fermentation suffers from low productivity and low product purity. Cell-recycle fermentation has become one of the methods to obtain high cell density, which results in higher productivity. Lactic acid fermentation was investigated in a cell-recycle membrane bioreactor at higher substrate concentrations of 100 and 120 g/dm3. A maximum cell density of 145 g/dm3 and a maximum productivity of 34 g/(dm3.h) were achieved in cell-recycle fermentation. In spite of complete consumption of substrate, there was a continuous increase in cell density in cell-recycle fermentation. Control of cell density in cell-recycle fermentation was attempted by cell bleeding and reduction in yeast extract concentration.

  8. Removal of N-nitrosamines by an aerobic membrane bioreactor.

    PubMed

    Wijekoon, Kaushalya C; Fujioka, Takahiro; McDonald, James A; Khan, Stuart J; Hai, Faisal I; Price, William E; Nghiem, Long D

    2013-08-01

    This study investigated the fate of eight N-nitrosamines during membrane bioreactor (MBR) treatment. The results suggest that biodegradation is mainly responsible for the removal of N-nitrosamines during MBR treatment. Other removal mechanisms were insignificant (e.g. adsorption to sludge) or not expected (e.g. photolysis and volatilization) given the experimental conditions and physicochemical properties of the N-nitrosamines studied here. N-nitrosamine removal efficiencies were from 24% to 94%, depending on their molecular properties. High removal of N-nitrosamines such as N-nitrosodimethylamine and N-nitrosodiethylamine could be explained by the presence of strong electron donating functional groups (EDG) in their structure. In contrast, N-nitrosomorpholine possessing the weak EDG morpholine was persistent to biodegradation. The removal efficiency of N-nitrosomorpholine was 24% and was the lowest amongst all N-nitrosamines investigated in this study.

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

    PubMed

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

    2008-01-01

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

  10. Comparison of textile dye treatment by biosorption and membrane bioreactor.

    PubMed

    Chamam, B; Heran, M; Amar, R Ben; Grasmick, A

    2007-12-01

    The Cassulfon CMR is a sulphuric textile dye mainly used to colour "jeans". It has a dark black-blue colour, with high intensity of colour and high mineral compounds (71% of dry matter). Direct filtration experiments were carried out to quantity the capacity of macro porous membranes (1.2, 0.2 or 0.1 microm) to separate organic matter and colour from the effluent. The results show that no direct membrane filtration was efficient. To evaluate the capacity of a biological way for the elimination of this dye, batch experiments were performed to quantify the dye sorption capacity on activated sludge. Results show the high capacity of the biomass to adsorb colour (more than 4gCOD gMLVSS(-1)) while 15% of COD remain in the soluble fraction. To evaluate the biodegradability potential of the sludge, continuous operations were carried out in a membrane bioreactor (MBR). Results confirm the very high MBR potential to treat such dye effluents. During operations, the organic load was progressively increased from 0.33 to 1.33 kg m(-3) d(-1) and the permeate quality was always free of suspended solids or turbidity. Moreover, the permeate COD values were always lower than 60 mg l(-1) and small permeate coloration only appeared during malfunctioning periods.

  11. Calicivirus Removal in a Membrane Bioreactor Wastewater Treatment Plant▿

    PubMed Central

    Sima, Laura C.; Schaeffer, Julien; Le Saux, Jean-Claude; Parnaudeau, Sylvain; Elimelech, Menachem; Le Guyader, Françoise S.

    2011-01-01

    To evaluate membrane bioreactor wastewater treatment virus removal, a study was conducted in southwest France. Samples collected from plant influent, an aeration basin, membrane effluent, solid sludge, and effluent biweekly from October 2009 to June 2010 were analyzed for calicivirus (norovirus and sapovirus) by real-time reverse transcription-PCR (RT-PCR) using extraction controls to perform quantification. Adenovirus and Escherichia coli also were analyzed to compare removal efficiencies. In the influent, sapovirus was always present, while the norovirus concentration varied temporally, with the highest concentration being detected from February to May. All three human norovirus genogroups (GI, GII, and GIV) were detected in effluent, but GIV was never detected in effluent; GI and GII were detected in 50% of the samples but at low concentrations. In the effluent, sapovirus was identified only once. An adenovirus titer showing temporal variation in influent samples was identified only twice in effluent. E. coli was always below the limit of detection in the effluent. Overall, the removal of calicivirus varied from 3.3 to greater than 6.8 log units, with no difference between the two main genogroups. Our results also demonstrated that the viruses are blocked by the membrane in the treatment plant and are removed from the plant as solid sludge. PMID:21666029

  12. One-year operation of single household membrane bioreactor plant.

    PubMed

    Matulova, Z; Hlavinek, P; Drtil, M

    2010-01-01

    This paper evaluates the results from a 12-month study of a single-household wastewater treatment plant with submerged membrane module (household MBR plant) that was monitored from winter to winter season. The samples were collected at least twice a week (an intensive research study at real conditions). The household MBR (membrane bioreactor) plant was linked to a family house with 4 residents. In this study the treatment plant was fed by real domestic wastewater. In contrast to most other experiments with small-scale WWTPs (wastewater treatment plants) carried out in laboratories and facilities of large municipal WWTPs (polygons) which guarantee stable and flexible operation but the characteristics of wastewater and activated sludge in these studies usually differ from those that occur in real small-scale/single-household WWTPs. One of the main goals of this research was to test the response of membrane and activated sludge to different conditions during real operation of the household MBR plant, such as a long period of zero influent/load, or vice versa the presence of a large amount of concentrated wastewater (e.g. during the weekend), very low winter temperatures (water temperature below 5-6 degrees C), high pH values, and the presence of domestic detergents.

  13. Membrane bio-reactor for textile wastewater treatment plant upgrading.

    PubMed

    Lubello, C; Gori, R

    2005-01-01

    Textile industries carry out several fiber treatments using variable quantities of water, from five to forty times the fiber weight, and consequently generate large volumes of wastewater to be disposed of. Membrane Bio-reactors (MBRs) combine membrane technology with biological reactors for the treatment of wastewater: micro or ultrafiltration membranes are used for solid-liquid separation replacing the secondary settling of the traditional activated sludge system. This paper deals with the possibility of realizing a new section of one existing WWTP (activated sludge + clariflocculation + ozonation) for the treatment of treating textile wastewater to be recycled, equipped with an MBR (76 l/s as design capacity) and running in parallel with the existing one. During a 4-month experimental period, a pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, and over 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surfactants removal of pilot plant was lower than that of the WWTP (90.5 and 93.2% respectively), while the BiAS removal was higher in the pilot plant (98.2 vs. 97.1). At the end cost analysis of the proposed upgrade is reported.

  14. Flux influence on membrane fouling in a membrane bioreactor system under real conditions with urban wastewater.

    PubMed

    Poyatos, Jose M; Molina-Munoz, Marisa; Delgado, Fernando; Gonzalez-Lopez, Jesus; Hontoria, Ernesto

    2008-12-01

    In order to evaluate the effect of flux on membrane fouling, the performance of a bench-scale submerged membrane bioreactor (MBR) equipped with ultrafiltration membranes (ZENON) was investigated under real conditions at different flux rates. The pilot plant was located at the wastewater treatment plant of the city of Granada (Spain). Influent used in the experiments came from the primary settling tank. Assays carried out under different operating conditions indicated that dTMP/dt increased in accordance with the increase in flux. The results showed a significant impact on the rate of transmembrane pressure, while the behavior of membrane fouling was logarithmic with respect to the flux. These findings could be of some importance for understanding the behavior of the membrane, since over 20.57 L m(-2) h(-1) the flux rate produced a significant increase in transmembrane pressure. The data therefore suggest that an increase in the net flux significantly affects membrane fouling.

  15. Effects of ionic strength on membrane fouling in a membrane bioreactor.

    PubMed

    Wang, Fangyuan; Zhang, Meijia; Peng, Wei; He, Yiming; Lin, Hongjun; Chen, Jianrong; Hong, Huachang; Wang, Aijun; Yu, Haiying

    2014-03-01

    In this study, the effects of ionic strength on membrane fouling in a membrane bioreactor (MBR) were investigated. Ionic strength in range of 0.005-0.05mol/L exerted no apparent impacts on the resistance of virgin membrane, fouled membrane and pore clogging. Thermodynamic analysis showed existences of a secondary energy minimum and an energy barrier in the process of the sludge flocs approaching to membrane surface. Increase in ionic strength could significantly reduce the energy barrier. It was revealed that there existed a critical ionic strength above that the energy barrier would disappear, facilitating adhesion of the foulants. Cake resistance was not significantly affected by the ionic strength, but highly depended on SMP in supernatant. The high cake resistance caused by SMP could be explained by the osmotic pressure mechanism. The obtained results provided new insights into membrane fouling in MBRs.

  16. Anaerobic treatment of distillery spent wash - a study on upflow anaerobic fixed film bioreactor.

    PubMed

    Acharya, Bhavik K; Mohana, Sarayu; Madamwar, Datta

    2008-07-01

    Anaerobic digestion of wastewater from a distillery industry having very high COD (1,10,000-1,90,000 mg/L) and BOD (50,000-60,000 mg/L) was studied in a continuously fed, up flow fixed film column reactor using different support materials such as charcoal, coconut coir and nylon fibers under varying hydraulic retention time and organic loading rates. The seed consortium was prepared by enrichment with distillery spent wash in a conventional type reactor having working capacity of 3 L and was used for charging the anaerobic column reactor. Amongst the various support materials studied the reactor having coconut coir could treat distillery spent wash at 8d hydraulic retention time with organic loading rate of 23.25 kg COD m(-3)d(-1) leading to 64% COD reduction with biogas production of 7.2 m3 m(-3)d(-1) having high methane yield without any pretreatment or neutralization of the distillery spent wash. This study indicates fixed film biomethanation of distillery spent wash using coconut coir as the support material appears to be a cost effective and promising technology for mitigating the problems caused by distillery effluent.

  17. Pyrosequencing reveals microbial community profile in anaerobic bio-entrapped membrane reactor for pharmaceutical wastewater treatment.

    PubMed

    Ng, Kok Kwang; Shi, Xueqing; Ong, Say Leong; Ng, How Yong

    2016-01-01

    In this study, pharmaceutical wastewater with high salinity and total chemical oxygen demand (TCOD) was treated by an anaerobic membrane bioreactor (AnMBR) and an anaerobic bio-entrapped membrane reactor (AnBEMR). The microbial populations and communities were analyzed using the 454 pyrosequencing method. The hydraulic retention time (HRT), membrane flux and mean cell residence time (MCRT) were controlled at 30.6h, 6L/m(2)h and 100d, respectively. The results showed that the AnBEMR achieved higher TCOD removal efficiency and greater biogas production compared to the AnMBR. Through DNA pyrosequencing analysis, both the anaerobic MBRs showed similar dominant groups of bacteria and archaea. However, phylum Elusimicrobia of bacteria was only detected in the AnBEMR; the higher abundance of dominant archaeal genus Methanimicrococcus found in the AnBEMR could play an important role in degradation of the major organic pollutant (i.e., trimethylamine) present in the pharmaceutical wastewater.

  18. Effect of leachate injection modes on municipal solid waste degradation in anaerobic bioreactor.

    PubMed

    Benbelkacem, H; Bayard, R; Abdelhay, A; Zhang, Y; Gourdon, R

    2010-07-01

    Three pilots simulated landfill bioreactors were used to investigate the effect of leachate injection modes on anaerobic digestion and biogas production from municipal solid waste. The technical modes used to increase waste moisture consisted of an initial saturation of the waste by flushing with leachate followed by a quick drainage, or weekly leachate injections with two different rates. The results confirmed that increasing moisture content is a key parameter to boost the biological reactions. Weekly leachate injection with high flow rate led to better results than the initial saturation of the waste in terms of biogas production kinetics. Water percolation was found to be an important factor to accelerate the degradation of solid waste. However, a modelling of the collected data by Gompertz model clearly showed that the intrinsic biogas potential determined on the initial solid waste was not reached with any of the progressive leachate injection modes.

  19. Arsenic remediation by formation of arsenic sulfide minerals in a continuous anaerobic bioreactor

    PubMed Central

    Rodriguez-Freire, Lucia; Moore, Sarah E.; Sierra-Alvarez, Reyes; Root, Robert A.; Chorover, Jon; Field, James A.

    2016-01-01

    Arsenic (As) is a highly toxic metalloid that has been identified at high concentrations in groundwater in certain locations around the world. Concurrent microbial reduction of arsenate (AsV) and sulfate (SO42-) can result in the formation of poorly soluble arsenic sulfide minerals (ASM). The objective of this research was to study As biomineralization in a minimal iron environment for the bioremediation of As-contaminated groundwater using simultaneous AsV and SO42- reduction. A continuous-flow anaerobic bioreactor was maintained at slightly acidic pH (6.25-6.50) and fed with AsV and SO42-, utilizing ethanol as an electron donor for over 250 d. A second bioreactor running under the same conditions but lacking SO42- was operated as a control to study the fate of As (without S). The reactor fed with SO42- removed an average 91.2% of the total soluble As at volumetric rates up to 2.9 mg As/(L∙h), while less than 5% removal was observed in the control bioreactor. Soluble S removal occurred with an S to As molar ratio of 1.2, suggesting the formation of a mixture of orpiment- (As2S3) and realgar-like (AsS) solid phases. Solid phase characterization using K-edge X-Ray absorption spectroscopy confirmed the formation of a mixture of As2S3 and AsS. These results indicate that a bioremediation process relying on the addition of a simple, low-cost electron donor offers potential to promote the removal of As from groundwater with naturally occurring or added sulfate by precipitation of ASM. PMID:26333155

  20. Role of nickel in high rate methanol degradation in anaerobic granular sludge bioreactors

    PubMed Central

    Fermoso, Fernando G.; Collins, Gavin; Bartacek, Jan; O’Flaherty, Vincent

    2008-01-01

    The effect of nickel deprivation from the influent of a mesophilic (30°C) methanol fed upflow anaerobic sludge bed (UASB) reactor was investigated by coupling the reactor performance to the evolution of the Methanosarcina population of the bioreactor sludge. The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5–15 g COD l−1 day−1 for 191 days. A clear limitation of the specific methanogenic activity (SMA) on methanol due to the absence of nickel was observed after 129 days of bioreactor operation: the SMA of the sludge in medium with the complete trace metal solution except nickel amounted to 1.164 (±0.167) g CH4-COD g VSS−1 day−1 compared to 2.027 (±0.111) g CH4-COD g VSS−1 day−1 in a medium with the complete (including nickel) trace metal solution. The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge. Continuation of the UASB reactor operation with the nickel limited sludge lead to incomplete methanol removal, and thus methanol accumulation in the reactor effluent from day 142 onwards. This methanol accumulation subsequently induced an increase of the acetogenic activity in the UASB reactor on day 160. On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased. Inclusion of 0.5 μM Ni (dosed as NiCl2) to the influent from day 165 onwards lead to the recovery of the methanol removal efficiency to 99% without VFA accumulation within 2 days of bioreactor operation. PMID:18247139

  1. Function of dynamic membrane in self-forming dynamic membrane coupled bioreactor.

    PubMed

    Wu, Y; Huang, X; Wen, X; Chen, F

    2005-01-01

    The Self-Forming Dynamic Membrane Coupled Bioreactor (SFDMBR), which uses coarse pore-sized material to separate solid and liquid in bioreactors, has some advantages compared with MBR using micro-/ultra-filtration membranes, for example, low module cost and high flux. The cake layer and gel layer formed on the surface and in the pores of the material during filtration played an important role, called self-forming dynamic membrane (DM), which mainly consisted of activated sludge. In this study, the function of DM in pollutant removal was investigated. It was found that DM could remove some organic matter (12.6 mg L(-1) on average) and total nitrogen (3.01 mg L(-1) on average) in the supernatant. Colloids and organic nitrogen were partly removed by DM while DOC, ammonia nitrogen and nitrate nitrogen removal by DM varied from negative to positive, which resulted from the combination of various biological activities, e.g. nitrification, biological utilization and so on. DO concentration in DM decreased with the depth and reached zero at about 1.5-2.5 mm depth. The organic degradation activity and nitrification activity of the biomass suspended in the bioreactor were higher than those of the biomass in the cake layer, which might be caused by the low DO concentration and low organic pollutant content in DM.

  2. In-situ utilization of generated electricity in an electrochemical membrane bioreactor to mitigate membrane fouling.

    PubMed

    Wang, Yun-Kun; Li, Wen-Wei; Sheng, Guo-Ping; Shi, Bing-Jing; Yu, Han-Qing

    2013-10-01

    How to mitigate membrane fouling remains a critical challenge for widespread application of membrane bioreactors. Herein, an antifouling electrochemical membrane bioreactor (EMBR) was developed based on in-situ utilization of the generated electricity for fouling control. In this system, a maximum power density of 1.43 W/m(3) and a current density of 18.49 A/m(3) were obtained. The results demonstrate that the formed electric field reduced the deposition of sludge on membrane surface by enhancing the electrostatic repulsive force between them. The produced H2O2 at the cathode also contributed to the fouling mitigation by in-situ removing the membrane foulants. In addition, 93.7% chemical oxygen demand (COD) removal and 96.5% NH4(+)-N removal in average as well as a low effluent turbidity of below 2 NTU were achieved, indicating a good wastewater treatment performance of the EMBR. This work provides a proof-of-concept study of an antifouling MBR with high wastewater treatment efficiency and electricity recovery, and implies that electrochemical control might provide another promising avenue to in-situ suppress the membrane fouling in MBRs.

  3. Foaming in membrane bioreactors: identification of the causes.

    PubMed

    Di Bella, Gaetano; Torregrossa, Michele

    2013-10-15

    Membrane bioreactors (MBRs) represent by now a well established alternative for wastewater treatment. Their increasing development is undoubtedly related to the several advantages that such technology is able to guarantee. Nevertheless, this technology is not exempt from operational problems; among them the foaming still represents an "open challenge" of the MBR field, due to the high complexity of phenomenon. Unfortunately, very little work has been done on the foaming in MBRs and further studies are required. Actually, there is not a distinct difference between conventional activated system and MBR: the main difference is that the MBR plants can retain most Extracellular Polymeric Substances (EPSs) in the bioreactor. For these reason, unlike conventional activated sludge systems, MBRs have experienced foaming in the absence of foam-forming micro-organisms. Nevertheless, the actual mechanisms of EPS production and the role of bacteria in producing foam in activated sludge in MBRs are still unclear. In this paper, the authors investigated the roles of EPS and foam-forming filamentous bacteria by analyzing samples from different pilot plants using MBRs. In particular, in order to define the macroscopic features and the role of EPS and filamentous bacteria, a Modified Scum Index (MSI) test was applied and proposed. Based on the MSI and the foam power test, the causes of biological foaming were identified in terms of the potential for foaming, the quality and the quantity of the foam. The results indicated that the MBR foaming was influenced significantly by the concentration of bound EPSs in the sludge. In addition, the quantity and stability of MBR scum increased when both bound EPSs and foam-forming filamentous bacteria were present in the activated sludge.

  4. Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology.

    PubMed

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

    2016-10-01

    Food waste was characterized for its potential use as substrate for anaerobic co-digestion in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater (WW). 90% of the particles had sizes under 0.5mm after grinding the food waste in a commercial food waste disposer. COD, nitrogen and phosphorus concentrations were 100, 2 and 20 times higher in food waste than their average concentrations in WW, but the relative flow contribution of both streams made COD the only pollutant that increased significantly when both substrates were mixed. As sulphate concentration in food waste was in the same range as WW, co-digestion of both substrates would increase the COD/SO4-S ratio and favour methanogenic activity in anaerobic treatments. The average methane potential of the food waste was 421±15mLCH4g(-1)VS, achieving 73% anaerobic biodegradability. The anaerobic co-digestion of food waste with WW is expected to increase methane production 2.9-fold. The settleable solids tests and the particle size distribution analyses confirmed that both treatment lines of a conventional WWTP (water and sludge lines) would be clearly impacted by the incorporation of food waste into its influent. Anaerobic processes are therefore preferred over their aerobic counterparts due to their ability to valorise the high COD content to produce biogas (a renewable energy) instead of increasing the energetic costs associated with the aeration process for aerobic COD oxidation.

  5. Influence of substrate on fouling in anoxic immersed membrane bioreactors.

    PubMed

    McAdam, Ewan J; Judd, Simon J; Cartmell, Elise; Jefferson, Bruce

    2007-09-01

    The influence of carbon substrate chemistry on membrane bioreactor (MBR) fouling in anoxic conditions has been evaluated. The use of a weak carboxylic acid (acetic acid) resulted in the production of large open-floc structures (up to 508microm) that were susceptible to breakage. Primary particles (d(10) and d(20) particle sizes, 5.5+/-1.3 and 15.3+/-8.2microm, respectively) and macromolecular soluble microbial products (SMPs) were generated, directly impacting on membrane fouling. The use of a primary alcohol (ethanol), on the other hand, encouraged the growth of flocs similar to activated sludge. These flocs produced low concentrations of primary particles (d(10) and d(20) particle sizes, 120.6+/-36.1 and 185.2+/-62.7microm, respectively) and high-molecular-weight SMP, and the particles had sufficient mechanical integrity to withstand shear. Consequently, the use of ethanol resulted in sufficient suppression of fouling to extend the filtration time by a factor of three. An increase in MLSS concentration did not directly impact upon fouling when operating with ethanol, primarily because of the low concentration of particulate matter produced.

  6. Effect of membrane polymeric materials on relationship between surface pore size and membrane fouling in membrane bioreactors

    NASA Astrophysics Data System (ADS)

    Miyoshi, Taro; Yuasa, Kotaku; Ishigami, Toru; Rajabzadeh, Saeid; Kamio, Eiji; Ohmukai, Yoshikage; Saeki, Daisuke; Ni, Jinren; Matsuyama, Hideto

    2015-03-01

    We investigated the effect of different membrane polymeric materials on the relationship between membrane pore size and development of membrane fouling in a membrane bioreactor (MBR). Membranes with different pore sizes were prepared using three different polymeric materials, cellulose acetate butyrate (CAB), polyvinyl butyral (PVB), and polyvinylidene fluoride (PVDF), and the development of membrane fouling in each membrane was evaluated by batch filtration tests using a mixed liquor suspension obtained from a laboratory-scale MBR. The results revealed that the optimal membrane pore size to mitigate membrane fouling differed depending on membrane polymeric material. For PVDF membranes, the degree of membrane fouling decreased as membrane pore size increased. In contrast, CAB membranes with smaller pores had less fouling propensity than those with larger ones. Such difference can be attributed to the difference in major membrane foulants in each membrane; in PVDF, they were small colloids or dissolved organics in which proteins are abundant, and in CAB, microbial flocs. The results obtained in this study strongly suggested that optimum operating conditions of MBRs differ depending on the characteristics of the used membrane.

  7. Yolo County's Accelerated Anaerobic and Aerobic Composting (Full-Scale Controlled Landfill Bioreactor) Project

    NASA Astrophysics Data System (ADS)

    Yazdani, R.; Kieffer, J.; Akau, H.; Augenstein, D.

    2002-12-01

    Sanitary landfilling is the dominant method of solid waste disposal in the United States, accounting for about 217 million tons of waste annually (U.S. EPA, 1997) and has more than doubled since 1960. In spite of increasing rates of reuse and recycling, population and economic growth will continue to render landfilling as an important and necessary component of solid waste management. Yolo County Department of Planning and Public Works, Division of Integrated Waste Management is demonstrating a new landfill technology called Bioreactor Landfill to better manage solid waste. In a Bioreactor Landfill, controlled quantities of liquid (leachate, groundwater, gray-water, etc.) are added and recirculated to increase the moisture content of the waste and improve waste decomposition. As demonstrated in a small-scale demonstration project at the Yolo County Central Landfill in 1995, this process significantly increases the biodegradation rate of waste and thus decreases the waste stabilization and composting time (5 to 10 years) relative to what would occur within a conventional landfill (30 to 50 years or more). When waste decomposes anaerobically (in absence of oxygen), it produces landfill gas (biogas). Biogas is primarily a mixture of methane, a potent greenhouse gas, carbon dioxide, and small amounts of Volatile Organic Compounds (VOC's) which can be recovered for electricity or other uses. Other benefits of a bioreactor landfill composting operation include increased landfill waste settlement which increases in landfill capacity and life, improved leachate chemistry, possible reduction of landfill post-closure management time, opportunity to explore decomposed waste for landfill mining, and abatement of greenhouse gases through highly efficient methane capture over a much shorter period of time than is typical of waste management through conventional landfilling. This project also investigates the aerobic decomposition of waste of 13,000 tons of waste (2.5 acre) for

  8. Influence of biofilm carriers on membrane fouling propensity in moving biofilm membrane bioreactor.

    PubMed

    Jamal Khan, S; Zohaib-Ur-Rehman; Visvanathan, C; Jegatheesan, V

    2012-06-01

    In moving biofilm membrane bioreactor (MB-MBR) sponge carriers for biofilm growth were coupled with conventional submerged membrane bioreactor (C-MBR). This study compared the fouling propensity of C-MBR with MB-MBR and investigated factors affecting fouling variations in both the systems. Membrane fouling tendencies were monitored in terms of trans-membrane pressure (TMP) and the fouling characterization included membrane fouling resistances in situ and specific cake resistance (SCR) in batch filtration cell. Comparison of TMP profiles depicted prolong filtration periods in MB-MBR. Cake layer resistance (R(c)), pore blocking resistance (R(p)) as well as SCR were higher in C-MBR. The study reveals that hybrid biomass in MB-MBR creates relatively more porous cake structure in the absence of filamentous bacteria which were found in abundance in C-MBR. Filamentous bacteria were also responsible for the release of high concentration of carbohydrates in the form of soluble extra polymeric substance (EPS) contributing to higher R(p) in C-MBR.

  9. Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash.

    PubMed

    Acharya, Bhavik K; Pathak, Hilor; Mohana, Sarayu; Shouche, Yogesh; Singh, Vasdev; Madamwar, Datta

    2011-08-01

    Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U(max)) and saturation value constant (K(B)) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor.

  10. Prediction of optimal biofilm thickness for membrane-attached biofilms growing in an extractive membrane bioreactor.

    PubMed

    Pavasant, P; Dos Santos, L M; Pistikopoulos, E N; Livingston, A G

    1996-11-05

    This article presents a mathematical model of membrane-attached biofilm (MAB) behavior in a single-tube extractive membrane bioreactor (STEMB). MABs can be used for treatment of wastewaters containing VOCs, treatment of saline wastewaters, and nitrification processes. Extractive membrane bioreactors (EMBs) are employed to prevent the direct contact between a toxic volatile pollutant and the aerated gas by allowing counterdiffusion of substrates; i.e., pollutant diffuses from the tube side into the biofilm, whereas oxygen diffuses from the shell side into the biofilm. This reduces the air stripping problems usually found in conventional bioreactors. In this study, the biodegradation of a toxic VOC (1,2-dichloroethane, DCE) present in a synthetic wastewater has been investigated. An unstructured model is used to describe cell growth and cell decay in the MAB. The model has been verified by comparing model predicted trends with experimental data collected over 5 to 20-day periods, and has subsequently been used to model steady states in biofilm behavior over longer time scales. The model is capable of predicting the correct trends in system variables such as biofilm thickness, DCE flux across the membrane, carbon dioxide evolution, and suspended biomass. Steady states (constant biofilm thickness and DCE flux) are predicted, and factors that affect these steady states, i.e., cell endogeneous decay rate, and biofilm attrition, are investigated. Biofilm attrition does not have a great influence on biofilm behavior at low values of detachment coefficient close to those typically reported in the literature. Steady-state biofilm thickness is found to be an important variable; a thin biofilm results in a high DCE flux across the membrane, but with the penalty of a high loss of DCE via air stripping. The optimal biofilm thickness at steady state can be determined by trading off the decrease in air stripping (desirable) and the decrease in DCE flux (undesirable) which occur

  11. Nitrification of ammonia nitrogen high concentration in membrane assisted bioreactor.

    PubMed

    Zabczyński, S; Surmacz-Górska, J; Miksch, K

    2003-01-01

    Use of the membrane-assisted bioreactors (MBR) in wastewater treatment can bring a lot of advantages. Usually COD removal achieves level 90% and nitrification of ammonia nitrogen concentrations typical for municipal wastewater performs without any disturbances, what was confirmed by large number of experiments. However, inhibition of nitrification of the high ammonia nitrogen concentration was noticed. In this study, the performance of ammonia-rich wastewater nitrification in membrane-assisted bioreactor (MBR) was examined. With SRT of 40, 32, 24 and 16 days any nitrification inhibition effect wasn't noticed. Ammonia nitrogen removal was around 98% and full nitrification was observed. At the sludge age equal to 12 d the first stage of nitrification was full, but the second stage of nitrification was incomplete. The variation in number and presence of the higher organisms were noticed at the all examined sludge ages. With SRT of 40, 32, 24 and 16 days the free ciliates were prominent organisms. At the sludge age of 12 days the domination of flagellates was observed The kinetic constants of the high-ammonia wastewater nitrification were calculated The average value of Vmax at the sludge age 12, 16 and 24 days was constant (4.7 mg NH4(+)-N/g MLSS h, 4.8 mg NH4(+)-N/g MLSS h and 4.8 mg NH4(+)-N/g MLSS, respectively), but the value of Km rose, when the sludge age increased (6.8 mg NH4(+)-N/L for 12 days, 11.3 mg NH4(+)-N/L for 16 days, 21.6 mg NH4(+)-N/L for 24 days). At the sludge age 32 and 40 days the increase of Vmax was observed (7.2 mg NH4(+)-N/g MLSS h and 12.5 mg NH4(+)-N/g MLSS h, respectively) and, also, changes of Km (6.8 mg NH4(+)-N/L and 44 mg NH4(+)-N/L, respectively. Concerning the second stage of nitrification value of Vmax decreased with the increase of the sludge age and the average Km varied from 20.3 to 31.3 mg NO2(-)-N/L.

  12. Pilot demonstration of energy-efficient membrane bioreactor (MBR) using reciprocating submerged membrane.

    PubMed

    Ho, Jaeho; Smith, Shaleena; Patamasank, Jaren; Tontcheva, Petia; Kim, Gyu Dong; Roh, Hyung Keun

    2015-03-01

    Membrane bioreactor (MBR) is becoming popular for advanced wastewater treatment and water reuse. Air scouring to "shake" the membrane fibers is most suitable and applicable to maintain filtration without severe and rapidfouling. However, membrane fouling mitigating technologies are energy intensive. The goal of this research is to develop an alternative energy-saving MBR system to reduce energy consumption; a revolutionary system that will directly compete with air scouring technologies currently in the membrane water reuse market. The innovative MBR system, called reciprocation MBR (rMBR), prevents membrane fouling without the use of air scouring blowers. The mechanism featured is a mechanical reciprocating membrane frame that uses inertia to prevent fouling. Direct strong agitation of the fiber is also beneficial for the constant removal of solids built up on the membrane surface. The rMBR pilot consumes less energy than conventional coarse air scouring MBR systems. Specific energy consumption for membrane reciprocation for the pilot rMBR system was 0.072 kWh/m3 permeate produced at 40 LMH, which is 75% less than the conventional air scouring in an MBR system (0.29 kWh/m3). Reciprocation of the hollow-fiber membrane can overcome the hydrodynamic limitations of air scouring or cross-flow membrane systems with less energy consumption and/or higher energy efficiency.

  13. Effect of membrane bioreactor solids retention time on reverse osmosis membrane fouling for wastewater reuse.

    PubMed

    Farias, Elizabeth L; Howe, Kerry J; Thomson, Bruce M

    2014-02-01

    The effect of the solids retention time (SRT) in a membrane bioreactor (MBR) on the fouling of the membranes in a subsequent reverse osmosis (RO) process used for wastewater reuse was studied experimentally using a pilot-scale treatment system. The MBR-RO pilot system was fed effluent from the primary clarifiers at a large municipal wastewater treatment plant. The SRT in the MBRs was adjusted to approximately 2, 10, and 20 days in three experiments. The normalized specific flux through the MBR and RO membranes was evaluated along with inorganic and organic constituents in the influent and effluent of each process. Increasing the SRT in the MBR led to an increase in the removal of bulk DOC, protein, and carbohydrates, as has been observed in previous studies. Increasing the SRT led to a decrease in the fouling of the MBR membranes, which is consistent with previous studies. However, the opposite trend was observed for fouling of the RO membranes; increasing the SRT of the MBR resulted in increased fouling of the RO membranes. These results indicate that the constituents that foul MBR membranes are not the same as those that foul RO membranes; to be an RO membrane foulant in a MBR-RO system, the constituents must first pass through the MBR membranes without being retained. Thus, an intermediate value of SRT may be best choice of operating conditions in an MBR when the MBR is followed by RO for wastewater reuse.

  14. Effects of filtration modes on membrane fouling behavior and treatment in submerged membrane bioreactor.

    PubMed

    Maqbool, Tahir; Khan, Sher Jamal; Lee, Chung-Hak

    2014-11-01

    Relaxation or backwashing is obligatory for effective operation of membrane module and intermittent aeration is helpful for nutrients removal. This study was performed to investigate effects of different filtration modes on membrane fouling behavior and treatment in membrane bioreactor (MBR) operated at three modes i.e., 12, 10 and 8min filtration and 3, 2, and 2min relaxation corresponding to 6, 5 and 4cycles/hour, respectively. Various parameters including trans-membrane pressure, specific cake resistance, specific oxygen uptake rate, nutrients removal and sludge dewaterability were examined to optimize the filtration mode. TMP profiles showed that MBR(8+2) with 8min filtration and 2min relaxation reduced the fouling rate and depicted long filtration time in MBR treating synthetic wastewater. MBR(12+3) was more efficient in organic and nutrients removal while denitrification rate was high in MBR(8+2).

  15. Novel magnetically induced membrane vibration (MMV) for fouling control in membrane bioreactors.

    PubMed

    Bilad, Muhammad R; Mezohegyi, Gergo; Declerck, Priscilla; Vankelecom, Ivo F J

    2012-01-01

    Conventional submerged membrane bioreactors (MBRs) rely on the coarse bubbles aeration to generate shear at the liquid-membrane interface to limit membrane fouling. Unfortunately, it is a very energy consuming method, still often resulting in a rapid decrease of membrane permeability and consequently in higher expenses. In this paper, the feasibility of a novel magnetically induced membrane vibration (MMV) system was studied in a lab-scale MBR treating synthetic wastewater. The effects on membrane fouling of applied electrical power of different operation strategies, of membrane flux and of the presence of multiple membranes on one vibrating engine on membrane fouling were investigated. The filtration performance was evaluated by determining the filtration resistance profiles and critical flux. The results showed clear advantages of the vibrating system over conventional MBR processes by ensuring higher fluxes at lower fouling rates. Intermittent vibration was found a promising strategy for both efficient fouling control and significant energy saving. The optimised MMV system is presumed to lead to significant energy and cost reduction in up-scaled MBR operations.

  16. Influence of membrane surface roughness on interfacial interactions with sludge flocs in a submerged membrane bioreactor.

    PubMed

    Zhao, Leihong; Shen, Liguo; He, Yiming; Hong, Huachang; Lin, Hongjun

    2015-05-15

    In this study, the interfacial interactions between sludge flocs and a rough membrane surface in a submerged membrane bioreactor were investigated. Models describing these interfacial interactions were firstly proposed based on the surface element integration (SEI) method. Surface properties of sludge flocs and membrane were experimentally determined to simulate the models through composite Simpson's rule. It was found that, roughness on membrane surface significantly decreased interaction strength, which enabled the sludge flocs to more easily attach on and detach from the rough membrane surface. Further analysis showed that the value of total interaction energy increased with asperity radius, while the strength of total interaction energy decreased with asperity height. Results also demonstrated that increase in floc size would significantly decrease the attractive specific total interaction with rough membrane surface. It was revealed that there existed a critical asperity radius above which the total interaction energy in certain separation distance coverage was continuously repulsive, facilitating membrane fouling control in MBRs. This study demonstrated the possibility to mitigate membrane fouling by "tailoring" membrane surface roughness.

  17. Distribution and mass transfer of dissolved oxygen in a multi-habitat membrane bioreactor.

    PubMed

    Tang, Bing; Qiu, Bing; Huang, Shaosong; Yang, Kanghua; Bin, Liying; Fu, Fenglian; Yang, Huiwen

    2015-04-01

    This work investigated the DO distribution and the factors influencing the mass transfer of DO in a multi-habitat membrane bioreactor. Through the continuous measurements of an on-line automatic system, the timely DO values at different zones in the bioreactor were obtained, which gave a detailed description to the distribution of oxygen within the bioreactor. The results indicated that the growth of biomass had an important influence on the distribution of oxygen. As the extension of operational time, the volumetric oxygen mass transfer coefficient (kLa) was generally decreased. With the difference in DO values, a complex environment combining anoxic and oxic state was produced within a single bioreactor, which provided a fundamental guarantee for the total removal of TN. Aeration rate, the concentration and apparent viscosity of MLSS have different influences on kLa, but adjusting the viscosity is a feasible method to improve the mass transfer of oxygen in the bioreactor.

  18. A novel membrane distillation-thermophilic bioreactor system: biological stability and trace organic compound removal.

    PubMed

    Wijekoon, Kaushalya C; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Cath, Tzahi Y; Nghiem, Long D

    2014-05-01

    The removal of trace organic compounds (TrOCs) by a novel membrane distillation-thermophilic bioreactor (MDBR) system was examined. Salinity build-up and the thermophilic conditions to some extent adversely impacted the performance of the bioreactor, particularly the removal of total nitrogen and recalcitrant TrOCs. While most TrOCs were well removed by the thermophilic bioreactor, compounds containing electron withdrawing functional groups in their molecular structure were recalcitrant to biological treatment and their removal efficiency by the thermophilic bioreactor was low (0-53%). However, the overall performance of the novel MDBR system with respect to the removal of total organic carbon, total nitrogen, and TrOCs was high and was not significantly affected by the conditions of the bioreactor. All TrOCs investigated here were highly removed (>95%) by the MDBR system. Biodegradation, sludge adsorption, and rejection by MD contribute to the removal of TrOCs by MDBR treatment.

  19. Anaerobic Membrane Bioreactors for Treatment of Wastewater at Contingency Locations

    DTIC Science & Technology

    2009-05-01

    lower nutrient requirements – methane production – treats high organic concentrations • The Bad – Slow growth rate of microorganisms – Delicate System...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) United States Air Force Academy,Department of...Civil and Environmental Engineering,USAF Academy ,CO,80840 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND

  20. The influence of zeolite (clinoptilolite) on the performance of a hybrid membrane bioreactor.

    PubMed

    Rezaei, M; Mehrnia, M R

    2014-04-01

    This work aims to investigate the effect of clinoptilolite on the performance of membrane bioreactor (MBR). The control membrane bioreactor without clinoptilolite (CMBR) and the hybrid membrane bioreactor with clinoptilolite (HMBR), in two parallel simultaneous MBRs within long and short term filtration experiments, were studied. Sludge properties, transmembrane pressure (TMP) rise as an index for membrane fouling and nutrient removal from synthetic wastewater in the CMBR and HMBR were compared. In HMBR, sludge properties improvement such as 22.5% rise in MLSS, 7% more accumulation of large particles, reduction of soluble microbial products (SMP) to half of this value in CMBR, no increase in sludge volume index (SVI) and 66% TMP reduced. The results of short term filtration showed that the trend of TMP increase in terms of flux will be slower in HMBR. Improvement of biological wastewater treatment quality and ease of membrane operation are concluded from this study.

  1. Enhancement of Nitrogen Removal in an Intermittent Aeration Membrane Bioreactor

    NASA Astrophysics Data System (ADS)

    He, Xiaojuan; Wisniewski, Christelle; Li, Xudong; Zhou, Qi

    2010-11-01

    An intermittent aerated membrane bioreactor was applied in laboratory scale to treat synthetic household wastewater. The system organic load and nitrogen load were 0.34 kgCODṡm-3ṡd-1 and 0.06 kgTNṡm-3ṡd-1, respectively. The hydraulic residence time was equal to 12 h and very long sludge residence times were imposed. Intermittent aeration, with anoxic-aerobic cycle of 30/60 minutes, was employed in the system. The results showed that 100% SS and >90% COD could be removed. The average removal efficiency of NH4-N and TN was 99.7% and 80%, respectively. A linear relationship between the fouling rate and the MLSS, MLVSS concentration was founded. The denitrification seemed to be the rate-limiting step for nitrogen removal. To enhance denitrification, the following strategies could be considered: 1) to select suitable aeration/non-aeration cycle, 2) to control the aeration intensity, 3) to feed the system at the beginning of non-aeration period, 4) to maintain high MLSS concentration.

  2. Exploring the potential of membrane bioreactors to enhance metals removal from wastewater: pilot experiences.

    PubMed

    Fatone, F; Eusebi, A L; Pavan, P; Battistoni, P

    2008-01-01

    The potential of membrane bioreactors to enhance the removal of selected metals from low loaded sewages has been explored. A 1400 litre pilot plant, equipped with an industrial submerged module of hollow fibre membranes, has been used in three different configurations: membrane bioreactor, operating in sequencing batch modality, for the treatment of real mixed municipal/industrial wastewater; membrane-assisted biosorption reactor, for the treatment of real leachate from municipal landfills; continuously fed membrane bioreactor, for the treatment of water charged with cadmium and nickel ions. The results show that: (a) in treating wastewaters with low levels of heavy metals (< one milligram per litre concentration), operating high sludge ages is not an effective strategy to significantly enhance the metals removal; (b) Hg and Cd are effectively removed already in conventional systems with gravitational final clarifiers, while Cu, Cr, Ni can rely on a additional performance in membrane bioreactors; (c) the further membrane effect is remarkable for Cu and Cr, while it is less significant for Ni. Basically, similar membrane effects recur in three different experimental applications that let us estimate the potential of membrane system to retain selected metal complexes. The future development of the research will investigate the relations between the membrane effect and the manipulable filtration parameters (i.e., permeate flux, solids content, filtration cycle).

  3. Membrane installation for enhanced up-flow anaerobic sludge blanket (UASB) performance.

    PubMed

    Liu, Yin; Zhang, Kaisong; Bakke, Rune; Li, Chunming; Liu, Haining

    2013-09-01

    It is postulated that up-flow anaerobic sludge blanket (UASB) reactor efficiency can be enhanced by a membrane immersed in the reactor to operate it as an anaerobic membrane bioreactor (AnMBR) for low-strength wastewater treatment. This postulate was tested by comparing the performance with and without a hollow fiber microfiltration membrane module immersed in UASB reactors operated at two specific organic loading rates (SOLR). Results showed that membrane filtration enhanced process performance and stability, with over 90% total organic carbon (TOC) removal consistently achieved. More than 91% of the TOC removal was achieved by suspended biomass, while less than 6% was removed by membrane filtration and digestion in the membrane attached biofilm during stable AnMBRs operation. Although the membrane and its biofilm played an important role in initial stage of the high SOLR test, linear increased TOC removal by bulk sludge mainly accounted for the enhanced process performance, implying that membrane led to enhanced biological activity of the suspended sludge. The high retention of active fine sludge particles in suspension was the main reason for this significant improvement of performance and biological activity, which led to decreased SOLR with time to a theoretical optimal level around 2  g COD/g MLVSS·d and the establishment of a microbial community dominated by Methanothrix-like microbes. It was concluded that UASB process performance can be enhanced by transforming such to AnMBR operation when the loading rate is too high for sufficient sludge retention, and/or when the effluent water quality demands are especially stringent.

  4. Membrane fouling in a membrane bioreactor (MBR): sludge cake formation and fouling characteristics.

    PubMed

    Ping Chu, Hiu; Li, Xiao-Yan

    2005-05-05

    A submerged membrane bioreactor (MBR) with a working volume of 1.4 L and a hollow fiber microfiltration membrane was used to treat a contaminated raw water supply at a short hydraulic retention time (HRT) of approximately 1 h. Filtration flux tests were conducted regularly on the membrane to determine various fouling resistances, and confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were employed to characterize the biofouling development and sludge cake formation on the membrane. The experimental results demonstrate that the MBR is highly effective in drinking water treatment for the removal of organic pollutants, ammonia, and UV absorbance. During the MBR operation, the fouling materials were not uniformly distributed on the entire surface of all of the membrane fibers. The membrane was covered partially by a static sludge cake that could not be removed by the shear force of aeration, and partially by a thin sludge film that was frequently washed away by aeration turbulence. The filtration resistance coefficients were 308.4 x 10(11) m(-1) on average for the sludge cake, 32.5 x 10(11) m(-1) on average for the dynamic sludge film, and increased from 10.5 x 10(11) to 59.7 x 10(11) m(-1) for the membrane pore fouling after 10 weeks of MBR operation at a filtration flux of 0.5 m3/m2 x d. Polysaccharides and other biopolymers were found to accumulate on the membrane, and hence decreased membrane permeability. More important, the adsorption of biopolymers on the membrane modified its surface property and led to easier biomass attachment and tighter sludge cake deposition, which resulted in a progressive sludge cake growth and serious membrane fouling. The sludge cake coverage on the membrane can be minimized by the separation, with adequate space, of the membrane filters, to which sufficient aeration turbulence can then be applied.

  5. Fouling of enhanced biological phosphorus removal-membrane bioreactors by humic-like substances.

    PubMed

    Poorasgari, Eskandar; König, Katja; Fojan, Peter; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-12-01

    Fouling by free extracellular polymeric substances was studied in an enhanced biological phosphorus removal-membrane bioreactor. It was demonstrated that the free extracellular polymeric substances, primarily consisting of humic-like substances, were adsorbed to the membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant. Infrared analyses indicated the presence of the humic-like substances on the membrane's active surface after filtration of the free extracellular polymeric substances suspension. Scanning electron microscopy showed the presence of a gel layer on the membrane surface after filtration of the free extracellular polymeric substances suspension. The gel layer caused a significant decline in water flux. This layer was not entirely removed by a backwashing, and the membrane's water flux could not be re-established. The membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant showed infrared spectra similar to that fouled by the free extracellular polymeric substances suspension in the laboratory. Thus, the results of this study show the importance of humic-like substances in irreversible fouling of enhanced biological phosphorus removal-membrane bioreactor systems.

  6. Composition and dynamics of microbial community in a zeolite biofilter-membrane bioreactor treating coking wastewater.

    PubMed

    Zhu, Xiaobiao; Tian, Jinping; Liu, Cong; Chen, Lujun

    2013-10-01

    In this study, a lab-scale anaerobic/anoxic/zeolite biofilter-membrane bioreactor (A1/A2/ZB-MBR) was designed to treat coking wastewater. The 454 pyrosequencing was used to obtain the composition and dynamics of microbial community about the treatment system. The results showed that the system yielded stable effluent chemical oxidation demand (158.5 ± 21.8 mg/L) and ammonia (8.56 ± 7.30 mg/L), but fluctuant total nitrogen (31.4-165.1 mg/L) concentrations. In addition, 66,256 16S rRNA gene sequences were obtained from A2 and ZB-MBR, and the microbial diversity and richness for five samples were determined. Although community compositions in the five samples were quite different, bacteria assigned to phylum Proteobacteria and class Flavobacteria commonly existed and dominated the microbial populations. The pyrosequencing analysis revealed that the microbial community shifted in the ZB-MBR with the presence of zeolite. Some taxa began to appear in ZB-MBR and contributed to the system performance. Additionally, Nitrosomonas and Nitrobacter gradually became the dominant ammonia-oxidizing bacteria and nitrite-oxidizing bacteria during the operation, respectively, which are favorable for the stabilized ammonia removal. Our results proved that the ZB-MBR is an alternative technique for treating coking wastewater.

  7. Effect of activated sludge properties and membrane operation conditions on fouling characteristics in membrane bioreactors.

    PubMed

    Choi, Hyeok; Zhang, Kai; Dionysiou, Dionysios D; Oerther, Daniel B; Sorial, George A

    2006-06-01

    Biofouling control is considered to be a major challenge in operating membrane bioreactors (MBRs) for the treatment of wastewater. This study examined the impact of biological, chemical, and physical properties of activated sludge on membrane filtration performance in laboratory-scale MBRs. Sludges with different microbial communities were produced using pseudo-continuous stirred-tank reactors and pseudo-plug flow reactors treating a synthetic paper mill wastewater. Various filtration resistances were used to investigate membrane fouling characteristics, and molecular biology tools targeting 16S ribosomal DNA gene sequences were used to identify predominant bacterial populations in the sludges or attached to the fouled membranes. Filtration experiments using axenic cultures of Escherichia coli, Acinetobacter calcoaceticus, and Gordonia amarae were also performed to better understand the initiation and development of biofouling. The results showed that the tendency of membranes to biofoul depended upon membrane operating conditions as well as the properties of the activated sludge in the MBR systems. Specific bacterial populations, which were not dominant in the activated sludges, were selectively accumulated on the membrane surface leading to the development of irreversible biofouling.

  8. [Fouling reasons and cleaning methods of nanofiltration membrane filtrated with the effluent of membrane bioreactor].

    PubMed

    Chen, Jian-hua; Huang, Xia

    2008-09-01

    In order to investigate the fouling reasons and cleaning methods of nanofiltration membrane fouled with the effluent of membrane bioreactor (MBR), FEG-SEM-EDS, FTIR, AFM and contact angle system, were applied to analyze the membrane fouling layer. The results showed that, the foulants included both organic and inorganic substances, which contained phosphorous (P) and magnesium (Mg). After investigations of membrane surfaces through different cleaning steps, it was showed that critic acid cleaning could remove Mg and most of P, which were inorganic; and subsequent sodium hydroxide cleaning could remove the residual P, which probably came from organic acid, organic phosphorous or protein. The roughness increased from 79.5 nm to 111.2 nm with fouling, but the hydrophilicity didn't change obviously according to the contact angle from 55.6 degrees to 62.1 degrees. But after acid cleaning, the roughness decreased to 51.9 nm and the contact angle changed to be 96.0 degrees, which showed the organic foulants were exposed and the surface changed to be hydrophobic. And after subsequent alkali cleaning, the roughness and the hydrophilicity were both close to those of the new membrane. These results concluded that acid cleaning followed by alkali cleaning could remove most of the foulants. It was also suggested that organic matters fouled the membrane in the initial stage, and inorganic matters aggravated the membrane fouling subsequently.

  9. Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling.

    PubMed

    Iorhemen, Oliver Terna; Hamza, Rania Ahmed; Tay, Joo Hwa

    2016-06-15

    The membrane bioreactor (MBR) has emerged as an efficient compact technology for municipal and industrial wastewater treatment. The major drawback impeding wider application of MBRs is membrane fouling, which significantly reduces membrane performance and lifespan, resulting in a significant increase in maintenance and operating costs. Finding sustainable membrane fouling mitigation strategies in MBRs has been one of the main concerns over the last two decades. This paper provides an overview of membrane fouling and studies conducted to identify mitigating strategies for fouling in MBRs. Classes of foulants, including biofoulants, organic foulants and inorganic foulants, as well as factors influencing membrane fouling are outlined. Recent research attempts on fouling control, including addition of coagulants and adsorbents, combination of aerobic granulation with MBRs, introduction of granular materials with air scouring in the MBR tank, and quorum quenching are presented. The addition of coagulants and adsorbents shows a significant membrane fouling reduction, but further research is needed to establish optimum dosages of the various coagulants/adsorbents. Similarly, the integration of aerobic granulation with MBRs, which targets biofoulants and organic foulants, shows outstanding filtration performance and a significant reduction in fouling rate, as well as excellent nutrients removal. However, further research is needed on the enhancement of long-term granule integrity. Quorum quenching also offers a strong potential for fouling control, but pilot-scale testing is required to explore the feasibility of full-scale application.

  10. Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling

    PubMed Central

    Iorhemen, Oliver Terna; Hamza, Rania Ahmed; Tay, Joo Hwa

    2016-01-01

    The membrane bioreactor (MBR) has emerged as an efficient compact technology for municipal and industrial wastewater treatment. The major drawback impeding wider application of MBRs is membrane fouling, which significantly reduces membrane performance and lifespan, resulting in a significant increase in maintenance and operating costs. Finding sustainable membrane fouling mitigation strategies in MBRs has been one of the main concerns over the last two decades. This paper provides an overview of membrane fouling and studies conducted to identify mitigating strategies for fouling in MBRs. Classes of foulants, including biofoulants, organic foulants and inorganic foulants, as well as factors influencing membrane fouling are outlined. Recent research attempts on fouling control, including addition of coagulants and adsorbents, combination of aerobic granulation with MBRs, introduction of granular materials with air scouring in the MBR tank, and quorum quenching are presented. The addition of coagulants and adsorbents shows a significant membrane fouling reduction, but further research is needed to establish optimum dosages of the various coagulants/adsorbents. Similarly, the integration of aerobic granulation with MBRs, which targets biofoulants and organic foulants, shows outstanding filtration performance and a significant reduction in fouling rate, as well as excellent nutrients removal. However, further research is needed on the enhancement of long-term granule integrity. Quorum quenching also offers a strong potential for fouling control, but pilot-scale testing is required to explore the feasibility of full-scale application. PMID:27314394

  11. Positive impact of biofilm on reducing the permeation of ampicillin through membrane for membrane bioreactor.

    PubMed

    Shen, Liang; Yuan, Xia; Shen, Weihuang; He, Ning; Wang, Yuanpeng; Lu, Haoliang; Lu, Yinghua

    2014-02-01

    The membrane bioreactor (MBR) has recently been the focus of research for the treatment of emerging contaminants such as antibiotics in wastewater. Although the biofilm on membrane in an MBR has been considered a cause of "membrane biofouling", its positive impact on removing pollutants has not been well-studied. This study was designed to investigate the retention effect on the permeation of ampicillin (AMP) by the biofilm coated on cellulose acetate (CA) membrane (commonly used for MBRs) utilizing a novel method based on microbial sensitivity test. The bioflim layer (thickness of 12-16μm) increased the resistance of the membrane for AMP permeation by 3-28%. Diffusion appeared to be the main driving force for the mass transfer of AMP across the membrane. Besides, the biofilm increased the retention of AMP by 23% but exhibited similar adsorption capacity with comparison of the suspended activated sludge, which indicates that the compact structure of the biofilm was the major contributor for the added retention effect on AMP by the biofilm-coated CA membrane. This study suggests that biofilm (biofouling) in MBRs increases the retention of small-molecule constituents such as antibiotics. A delicate tradeoff between reduced wastewater throughput and increased retention of contaminants should be obtained when an MBR is designed and operated.

  12. Co-digestion of mixed industrial sludge with municipal solid wastes in anaerobic simulated landfilling bioreactors.

    PubMed

    Ağdağ, Osman Nuri; Sponza, Delia Teresa

    2007-02-09

    In this study, the feasibility of the anaerobic co-digestion of a mixed industrial sludge with municipal solid wastes (MSW) was investigated in three simulated anaerobic landfilling bioreactors during a 150-day period. All of the reactors were operated with leachate recirculation. One of them was loaded only with MSW (control reactor); the second reactor was loaded with mixed industrial sludge and MSW, the weight ratio of the MSW to mixed industrial sludge was 1:1 (based on dry solid) (Run 1); the third reactor was loaded with mixed industrial sludge and MSW, the weight ratio of the MSW to mixed industrial sludge was 1:2 (based on dry solid) (Run 2). The VFA concentrations decreased significantly in Run 1 and Run 2 reactors at the end of 150 days. The pH values were higher in Run 1 and Run 2 reactors compared to control reactor. The differences between leachate characteristics, the biodegradation and the bioefficiency of the reactors were compared. The NH(4)-N concentrations released to leachate from mixed sludge in Run 1 and Run 2 reactors were lower than that of control reactor. The BOD(5)/COD ratios in Run 1 and Run 2 reactors were lower than that of control reactor at the end of 150 days. Cumulative methane gas productions and methane percentages were higher in Run 1 and Run 2 reactors. Reductions in waste quantity, carbon percentage and settlement of the waste were better in Run 1 and Run 2 reactors compared to control reactor at the end of 150 days. Furthermore, TN and TP removals in waste were higher in reactors containing industrial sludge compared to control. The toxicity test results showed that toxicity was observed in reactors containing industrial mixed sludge.

  13. Effect of membrane characteristics on the performance of membrane bioreactors for oily wastewater treatment.

    PubMed

    Mafirad, S; Mehrnia, M R; Sarrafzadeh, M H

    2011-01-01

    Influence of membrane material and pore size on the performance of a submerged membrane bioreactor (sMBR) for oily wastewater treatment was investigated. The sMBR had a working volume of about 19 L with flat sheet modules at the same hydrodynamic conditions. Five types of micro- and ultra-polymeric membranes containing cellulose acetate (CA), cellulose nitrate (CN), polyamide (PA), polyvinylidene difluoride (PVDF) and polyethersulfone (PES) were used and their filtration performance in terms of permeability, permeate quality and fouling intensity were evaluated. Characterization of the membranes was done by performing some analysis such as pore size distribution; contact angle and scanning electronic microscopy (SEM) microphotograph on all membranes. The quality of permeates from each membrane was identified by measuring chemical oxygen demand (COD). The results showed more irreversible fouling intensity for membranes with larger pore size which can be due to more permeation of bioparticles and colloids inside the pores. Membrane characteristics have a major role in the preliminary time of the filtration before cake layer formation so that the PA with the highest hydrophilicity had the lowest permeability decline by fouling in this period. Also, the PVDF and PES membranes had better performance according to better permeate quality in the preliminary time of the filtration related to smaller pore size and also their better fouling resistance and chemical stability properties. However, all membranes resulted in the same permeability and permeate quality after cake layer formation. An overall efficiency of about 95% in COD removal was obtained for oily wastewater treatment by the membranes used in this study.

  14. Sequential anaerobic-aerobic decolourization of a real textile wastewater in a two-phase partitioning bioreactor.

    PubMed

    Tomei, M Concetta; Mosca Angelucci, Domenica; Daugulis, Andrew J

    2016-12-15

    This work describes the application of a solid-liquid two-phase partitioning bioreactor (TPPB) for the removal of colour from a real textile wastewater containing reactive azo-dyes. Four polymers were tested over the pH range of 4-9 to select the most effective absorbant to be used as the partitioning phase in the TPPB. The best results were obtained with Hytrel 8206 at pH4 achieving ~70% colour removal, based on the dominant wavelength, in the first 5h of contact time, and 84% after 24h. Wastewater treatment was undertaken in a solid-liquid TPPB operated with Hytrel 8206 in sequential anaerobic-aerobic configuration. The reaction time of 23h was equally distributed between the anaerobic and aerobic phases and, to favour colour uptake, the pH was controlled at 4.5 in the first 4h of the anaerobic phase, and then increased to 7.5. Colour removal (for the dominant wavelength, 536nm) increased from 70 to 85% by modifying the bioreactor operation from single-phase to TPPB mode. Based on COD measurements nearly complete biodegradation of the intermediates produced in the anaerobic phase was obtained, both in the single-phase and two-phase mode, with better performance of the TPPB system reaching 75% CODDye removal.

  15. Functional diversity and dynamics of bacterial communities in a membrane bioreactor for the treatment of metal-working fluid wastewater.

    PubMed

    Grijalbo, Lucía; Garbisu, Carlos; Martín, Iker; Etxebarria, Javier; Gutierrez-Mañero, F Javier; Lucas Garcia, Jose Antonio

    2015-12-01

    An extensive microbiological study has been carried out in a membrane bioreactor fed with activated sludge and metal-working fluids. Functional diversity and dynamics of bacterial communities were studied with different approaches. Functional diversity of culturable bacterial communities was studied with different Biolog™ plates. Structure and dynamics of bacterial communities were studied in culturable and in non-culturable fractions using a 16S rRNA analysis. Among the culturable bacteria, Alphaproteobacteria and Gammaproteobacteria were the predominant classes. However, changes in microbial community structure were detected over time. Culture-independent analysis showed that Betaproteobacteria was the most frequently detected class in the membrane bioreactor (MBR) community with Zoogloea and Acidovorax as dominant genera. Also, among non-culturable bacteria, a process of succession was observed. Longitudinal structural shifts observed were more marked for non-culturable than for culturable bacteria, pointing towards an important role in the MBR performance. Microbial community metabolic abilities assessed with Biolog™ Gram negative, Gram positive and anaerobic plates also showed differences over time for Shannon's diversity index, kinetics of average well colour development, and the intensely used substrates by bacterial community in each plate.

  16. Effect of hydraulic retention time and sludge recirculation on greenhouse gas emission and related microbial communities in two-stage membrane bioreactor treating solid waste leachate.

    PubMed

    Nuansawan, Nararatchporn; Boonnorat, Jarungwit; Chiemchaisri, Wilai; Chiemchaisri, Chart

    2016-06-01

    Methane (CH4) and nitrous oxide (N2O) emissions and responsible microorganisms during the treatment of municipal solid waste leachate in two-stage membrane bioreactor (MBR) was investigated. The MBR system, consisting of anaerobic and aerobic stages, were operated at hydraulic retention time (HRT) of 5 and 2.5days in each reactor under the presence and absence of sludge recirculation. Organic and nitrogen removals were more than 80% under all operating conditions during which CH4 emission were found highest under no sludge recirculation condition at HRT of 5days. An increase in hydraulic loading resulted in a reduction in CH4 emission from anaerobic reactor but an increase from the aerobic reactor. N2O emission rates were found relatively constant from anaerobic and aerobic reactors under different operating conditions. Diversity of CH4 and N2O producing microorganisms were found decreasing when hydraulic loading rate to the reactors was increased.

  17. Hybrid adaptive optimal control of anaerobic fluidized bed bioreactor for the de-icing waste treatment.

    PubMed

    Seok, Jonghyuk

    2003-04-24

    Hybrid adaptive control strategy was developed and tested for the degradation of propylene glycol, a major component in de-icing waste, in an anaerobic fluidized bed bioreactor (AFBR). A linearized model with time-varying parameters was first employed to describe the dynamic behavior of the AFBR using a recursive off-line system identification method. A hybrid adaptive control strategy was then tested using a recursive off-line system identification routine followed by an on-line adaptive optimal control algorithm. The objective of the controller was to achieve the desired set point value of the propionate concentration (stand-alone control output variable) by manipulating the dilution rate (control input variable). To do so, the optimal control law was developed by minimizing a cost function with constraint equations. This novel idea was successfully applied to the underlying system for 200 h. The set point (700 mg HPrl(-1)) was achieved even in the case where the feed concentration suddenly increased by 50% (9000 mg HPrl(-1) to 13500 mg HPrl(-1)).

  18. Combined Industrial Wastewater Treatment in Anaerobic Bioreactor Posttreated in Constructed Wetland

    PubMed Central

    Zeb, Bibi Saima; Mahmood, Qaisar; Jadoon, Saima; Pervez, Arshid; Irshad, Muhammad; Bilal, Muhammad; Bhatti, Zulfiqar Ahmad

    2013-01-01

    Constructed wetland (CW) with monoculture of Arundo donax L. was investigated for the posttreatment of anaerobic bioreactor (ABR) treating combined industrial wastewater. Different dilutions of combined industrial wastewater (20, 40, 60, and 80) and original wastewater were fed into the ABR and then posttreated by the laboratory scale CW. The respective removal efficiencies of COD, BOD, TSS, nitrates, and ammonia were 80%, 78–82%, 91.7%, 88–92%, and 100% for original industrial wastewater treated in ABR. ABR was efficient in the removal of Ni, Pb, and Cd with removal efficiencies in the order of Cd (2.7%) > Ni (79%) > Pb (85%). Posttreatment of the ABR treated effluent was carried out in lab scale CW containing A. donax L. CW was effective in the removal of COD and various heavy metals present in ABR effluents. The posttreatment in CW resulted in reducing the metal concentrations to 1.95 mg/L, 0 mg/L, and 0.004 mg/L for Ni, Pb, and Cd which were within the permissible water quality standards for industrial effluents. The treatment strategy was effective and sustainable for the treatment of combined industrial wastewater. PMID:24396832

  19. Iron and manganese removal from textile effluents in anaerobic attached-growth bioreactor filled with coirfibres.

    PubMed

    Jayaweera, M W; Gomes, P I A; Wijeyekoon, S L J

    2007-01-01

    A laboratory scale study on Fe and Mn removal in upflow anaerobic bioreactor of a working volume of 20 L with coir fibre as the filter medium was investigated for a period of 312 days. The maximum Fe and Mn levels considered were 10 and 5 mg/L respectively, which are the typical average values of textile effluents subsequent to the primary and secondary treatments. Ten sub-experimental runs were conducted with varying HRTs (5 days to 1 day), ratios of COD:SO42- (20 to 3.5), Fe levels (0.005 to 10 mg/L) and Mn levels (0 to 5 mg/L). COD:SO2 of 3.5 was identified as the optimum point at which sulphate reducing bacteria (SRBs) out competed methane producing bacteria (MPBs) and further reduction of this ratio caused total and/or significant inhibition of MPBs, thus building sulphate reducing conditions. The effluent contained Fe and Mn below the permissible levels (1.6 and 1.1 mg/L for Fe and Mn, respectively) stipulated by US National Pollution Discharge Elimination System (NPDES) for inland surface waters at HRTs higher than 3 days. Results of the mass balance showed more Fe accumulation (60%) in sediments whereas 27% in the filter media. An opposite observation was noticed for Mn.

  20. Effects of microbial degradation of biofoulants on microfiltration membrane performance in a membrane bioreactor.

    PubMed

    Okamura, Daisuke; Mori, Yoshihiko; Hashimoto, Tomotaka; Hori, Katsutoshi

    2010-11-15

    In membrane bioreactors (MBRs) for wastewater treatment, membrane fouling, particularly biofouling caused by soluble microbial products (SMP), is a nuisance problem causing decreases in permeation flux. In a previous study, we identified primary biofoulants of microfiltration (MF) membranes in SMP as polysaccharides containing uronic acids that undergo inter- and intramolecular ionic cross-linking by polyvalent cations, forming a gelatinous mass that clogs membrane pores. In the present study, we therefore attempted to isolate biofoulant-degrading microorganisms from activated sludge on a polygalacturonic acid-overlaid agar medium and evaluate their efficiency for preventing biofouling of MF membranes. Among the isolates, the fungal strain HO1 identified as Phialemonium curvatum degraded 30% of polysaccharides containing uronic acids into smaller molecules in a SMP solution containing a high concentration of saccharides after 30 days of cultivation. Microfiltration tests using a laboratory-scale submerged MBR indicated that the filtration resistance of this degraded SMP solution was lower than that of the control SMP solution without fungal inoculation. Importantly, accumulation of gelatinous mass on the membrane responsible for biofouling was avoided in the SMP solution augmented with P. curvatum HO1 during the microfiltration test. This is the first report to describe a new method for avoiding biofouling of MBRs by microbial degradation of primary biofoulants.

  1. Membrane photobioreactors for integrated microalgae cultivation and nutrient remediation of membrane bioreactors effluent.

    PubMed

    Marbelia, L; Bilad, M R; Passaris, I; Discart, V; Vandamme, D; Beuckels, A; Muylaert, K; Vankelecom, Ivo F J

    2014-07-01

    The feasibility of a new concept of wastewater treatment by combining a membrane bioreactor (MBR) and a microalgae membrane photobioreactor (MPBR) is assessed in this study. In this system, the organic carbon present in wastewater is expected to be fully oxidized in the MBR, while the nutrients are removed via the subsequent MPBR treatment. The effluent of a lab-scale MBR was fed into a PBR and a MPBR which served as growing medium for Chlorella vulgaris. The MPBRs demonstrated their superiority by limiting the algae wash-out, thus increasing the allowable optimum dilution rate (Dopt). At these corresponding Dopt values, 3.5 and 2 times higher biomass concentrations and volumetric productivities respectively were achieved by the MPBR. It is also possible to run the MPBR at still higher biomass concentration, thus enabling a smaller footprint and higher nutrient removal efficiency. However, reduced nutrient removal efficiencies were found to be one possible drawback.

  2. Inhibitory Effect of Long-Chain Fatty Acids on Biogas Production and the Protective Effect of Membrane Bioreactor

    PubMed Central

    Dasa, Kris Triwulan; Westman, Supansa Y.; Cahyanto, Muhammad Nur; Niklasson, Claes

    2016-01-01

    Anaerobic digestion of lipid-containing wastes for biogas production is often hampered by the inhibitory effect of long-chain fatty acids (LCFAs). In this study, the inhibitory effects of LCFAs (palmitic, stearic, and oleic acid) on biogas production as well as the protective effect of a membrane bioreactor (MBR) against LCFAs were examined in thermophilic batch digesters. The results showed that palmitic and oleic acid with concentrations of 3.0 and 4.5 g/L resulted in >50% inhibition on the biogas production, while stearic acid had an even stronger inhibitory effect. The encased cells in the MBR system were able to perform better in the presence of LCFAs. This system exhibited a significantly lower percentage of inhibition than the free cell system, not reaching over 50% at any LCFA concentration tested. PMID:27699172

  3. Membrane Distillation Bioreactor (MDBR) - A lower Green-House-Gas (GHG) option for industrial wastewater reclamation.

    PubMed

    Goh, Shuwen; Zhang, Jinsong; Liu, Yu; Fane, Anthony G

    2015-12-01

    A high-retention membrane bioreactor system, the Membrane Distillation Bioreactor (MDBR) is a wastewater reclamation process which has the potential to tap on waste heat generated in industries to produce high quality product water. There are a few key factors which could make MDBR an attractive advanced treatment option, namely tightening legal requirements due to increasing concerns on the micropollutants in industrial wastewater effluents as well as concerns over the electrical requirement of pressurized advanced treatment processes and greenhouse gas emissions associated with wastewater reclamation. This paper aims to provide a consolidated review on the current state of research for the MDBR system and to evaluate the system as a possible lower Green House Gas (GHG) emission option for wastewater reclamation using the membrane bioreactor-reverse osmosis (MBR-RO) system as a baseline for comparison. The areas for potential applications and possible configurations for MDBR applications are discussed.

  4. Process-Oriented Review of Bacterial Quorum Quenching for Membrane Biofouling Mitigation in Membrane Bioreactors (MBRs)

    PubMed Central

    Bouayed, Naila; Dietrich, Nicolas; Lafforgue, Christine; Lee, Chung-Hak; Guigui, Christelle

    2016-01-01

    Quorum Quenching (QQ) has been developed over the last few years to overcome practical issues related to membrane biofouling, which is currently the major difficulty thwarting the extensive development of membrane bioreactors (MBRs). QQ is the disruption of Quorum Sensing (QS), cell-to-cell communication enabling the bacteria to harmonize their behavior. The production of biofilm, which is recognized as a major part of the biocake formed on a membrane surface, and which leads to biofouling, has been found to be one of the bacterial behaviors controlled by QS. Since the enzymatic disruption of QS was reported to be efficient as a membrane biofouling mitigation technique in MBRs, the application of QQ to lab-scale MBRs has been the subject of much research using different approaches under different operating conditions. This paper gives an overview of the effectiveness of QQ in mitigating membrane biofouling in MBRs. It is based on the results of previous studies, using two microbial strains, Rhodococcus sp. BH4 and Pseudomonas sp. 1A1. The effect of bacterial QQ on the physical phenomena of the MBR process is analyzed, adopting an original multi-scale approach. Finally, the potential influence of the MBR operating conditions on QQ effectiveness is discussed. PMID:27983578

  5. Enzymatic hydrolysis of cellulose in a membrane bioreactor: assessment of operating conditions.

    PubMed

    Liu, Jianguo; Lu, Jianren; Cui, Zhanfeng

    2011-06-01

    The optimization of operating conditions for cellulose hydrolysis was systemically undertaken using an ultra-scaled down membrane bioreactor based on the parameter scanning ultrafiltration apparatus. The bioconversion of cellulose saccharification was carried out with freely suspended cellulase from Aspergillus niger as the biocatalyst. The polyethersulfone ultrafiltration membranes with a molecular weight cutoff of 10 kDa were used to construct the enzymatic membrane bioreactor, with the membrane showing a complete retaining of cellulase and cellobiase. The influence of solution pH, temperature, salt (NaCl) concentration, presence of cellobiase, cellulose-to-enzyme ratio and stirring speed on reducing sugar production was examined. The results showed that the addition of an appropriate amount of NaCl or cellobiase had a positive effect on reducing sugar formation. Under the identified optimal conditions, cellulose hydrolysis in the enzymatic membrane bioreactor was tested for a long period of time up to 75 h, and both enzymes and operation conditions demonstrated good stability. Also, the activation energy (E(a)) of the enzymatic hydrolysis, with a value of 34.11 ± 1.03 kJ mol(-1), was estimated in this study. The operational and physicochemical conditions identified can help guide the design and operation of enzymatic membrane bioreactors at the industrial scale for cellulose hydrolysis.

  6. Artificial neural network based modeling to evaluate methane yield from biogas in a laboratory-scale anaerobic bioreactor.

    PubMed

    Nair, Vijay V; Dhar, Hiya; Kumar, Sunil; Thalla, Arun Kumar; Mukherjee, Somnath; Wong, Jonathan W C

    2016-10-01

    The performance of a laboratory-scale anaerobic bioreactor was investigated in the present study to determine methane (CH4) content in biogas yield from digestion of organic fraction of municipal solid waste (OFMSW). OFMSW consists of food waste, vegetable waste and yard trimming. An organic loading between 40 and 120kgVS/m(3) was applied in different runs of the bioreactor. The study was aimed to focus on the effects of various factors, such as pH, moisture content (MC), total volatile solids (TVS), volatile fatty acids (VFAs), and CH4 fraction on biogas production. OFMSW witnessed high CH4 yield as 346.65LCH4/kgVS added. A target of 60-70% of CH4 fraction in biogas was set as an optimized condition. The experimental results were statistically optimized by application of ANN model using free forward back propagation in MATLAB environment.

  7. Microbial monitoring by molecular tools of a two-phase anaerobic bioreactor treating fruit and vegetable wastes.

    PubMed

    Bouallagui, H; Torrijos, M; Godon, J J; Moletta, R; Cheikh, R Ben; Touhami, Y; Delgenes, J P; Hamdi, M

    2004-05-01

    Microbial consortia in a two-phase, anaerobic bioreactor using a mixture of fruit and vegetable wastes were established. Bacterial and archaeal communities obtained by a culture-independent approach based on single strand conformation polymorphism analysis of total 16S rDNA showed the adaptation of the microflora to the process parameters. Throughout the 90 d of the study, the species composition of the bacterial community changed significantly. Bacterial 16S rDNA showed at least 7 different major species with a very prominent one corresponding to a Megasphaera elsdenii whereas bacterial 16S rDNA of a methanization bioreactor showed 10 different major species. After two weeks, Prevotella ruminicola became major and its dominance increased continuously until day 50. After an acid shock at pH 5, the 16S rDNA archaeal patterns in the acidogenic reactor showed two major prominent species corresponding to Methanosphaera stadtmanii and Methanobrevibacter wolinii, a hydrogenotrophic bacterium.

  8. Assessment of anti-fouling strategies for membrane coupled with upflow anaerobic sludge blanket (MUASB) process.

    PubMed

    Tran, Thao Minh; Ye, Yun; Chen, Vicki; Stuetz, Richard; Le-Clech, Pierre

    2013-01-01

    In this novel process, domestic wastewater was filtered by a hollow-fibre membrane coupled with an upflow anaerobic sludge blanket (MUASB) bioreactor. To improve the process sustainability and decrease energy costs, the membranes were operated under low fluxes with little, or no, shear. The efficiency of anti-fouling strategies, including relaxation, backwashing and supply of low aeration and stir rates, was assessed through detailed characterization of the fouling layers. Results indicated that backwashing was more efficient than relaxation, even when the systems were operated under the same flux productivity. In terms of shear supply, stir provided a better fouling limitation strategy compared to aeration, at similar shear stress values. Physical and chemical cleaning methods were applied to recover three fouling fractions (i.e. cake, residual and irreversible) for better characterization of the fouling layers. Under the sustainable operating conditions used in this study, most of the fouling was easily reversible by simple rinsing. In addition, permanent and irreversible fouling, resulting in the need for frequent chemical cleanings and potential membrane degradation, is limited once small shear stresses are applied. These outcomes are expected to form the basis for the future assessment of trade-off between operation, maintenance and replacement costs of membrane filtration processes used in wastewater treatment.

  9. Metaproteomic analysis of biocake proteins to understand membrane fouling in a submerged membrane bioreactor.

    PubMed

    Zhou, Zhongbo; Meng, Fangang; He, Xiang; Chae, So-Ryong; An, Yujia; Jia, Xiaoshan

    2015-01-20

    Metaproteomic analyses, including two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) separation and matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF)/TOF mass spectrometer (MS) detection, were used to trace and identify biocake proteins on membranes in a bench-scale submerged membrane bioreactor (MBR). 2D-PAGE images showed that proteins in the biocake (S3) at a low transmembrane pressure (TMP) level (i.e., before the TMP jump) had larger gray intensities in the pH 5.5–7.0 region regardless of the membrane flux, similar to soluble microbial product (SMP) proteins. However, the biocake (S2 and S4) at a high TMP level (i.e., after the TMP jump) had many more proteins in the pH range of 4.0–5.5, similar to extracellular polymeric substance (EPS) proteins. Such similarities between biocake proteins and SMP or EPS proteins can be useful for tracing the sources of proteins resulting in membrane fouling. In total, 183 differentially abundant protein spots were marked in the three biocakes (S2, S3, and S4). However, only 32 protein spots co-occurred in the 2D gels of the three biocakes, indicating that membrane fluxes and TMP evolution levels had significant effects on the abundance of biocake proteins. On the basis of the MS and MS/MS data, 23 of 71 protein spots were successfully identified. Of the 23 proteins, outer membrane proteins (Omp) were a major contributor (60.87%). These Omps were mainly from potential surface colonizers such as Aeromonas, Enterobacter, Pseudomonas, and Thauera. Generally, the metaproteomic analysis is a useful alternative to trace the sources and compositions of biocake proteins on the levels of molecules and bacteria species that can provide new insight into membrane fouling.

  10. Integrated approach to characterize fouling on a flat sheet membrane gravity driven submerged membrane bioreactor.

    PubMed

    Fortunato, Luca; Jeong, Sanghyun; Wang, Yiran; Behzad, Ali R; Leiknes, TorOve

    2016-12-01

    Fouling in membrane bioreactors (MBR) is acknowledged to be complex and unclear. An integrated characterization methodology was employed in this study to understand the fouling on a gravity-driven submerged MBR (GD-SMBR). It involved the use of different analytical tools, including optical coherence tomography (OCT), liquid chromatography with organic carbon detection (LC-OCD), total organic carbon (TOC), flow cytometer (FCM), adenosine triphosphate analysis (ATP) and scanning electron microscopy (SEM). The three-dimensional (3D) biomass morphology was acquired in a real-time through non-destructive and in situ OCT scanning of 75% of the total membrane surface directly in the tank. Results showed that the biomass layer was homogeneously distributed on the membrane surface. The amount of biomass was selectively linked with final destructive autopsy techniques. The LC-OCD analysis indicated the abundance of low molecular weight (LMW) organics in the fouling composition. Three different SEM techniques were applied to investigate the detailed fouling morphology on the membrane.

  11. Dynamic membrane behaviours during constant flux filtration in membrane bioreactor coupled with mesh filter.

    PubMed

    Poostchi, Amir Ali; Mehrnia, Mohammad Reza; Rezvani, Fariba

    2015-01-01

    This study investigated the long-term filtration of mesh filter with the formed dynamic membrane in bioreactor. The trend of transmembrane pressure (TMP) variations highly corresponded to the thickness and compactness index of dynamic membrane. The dynamic membrane was fractionated by applying two cleaning protocols, that is, rinsing and chemical cleaning. The desorbed fraction, consisting of soluble microbial products (>70%), provided a stickiness surface for formation of consecutive biomass layer which featured a high concentration of extracellular polymeric substances (>75%). The chemical oxygen demand (COD) removal was 70%, 89%, and 92% for period of 0-26, 26-49, and 49-67 day, respectively, which indicated that further development of dynamic membrane increased the TMP without improvement in the effluent quality (TMP: 50-200 mbar, COD removal: 89%; TMP: 200-600 mbar, COD removal: 92%). The average NH4+-N and TN removal was about 76% and 21%, respectively. The effluent turbidity fell less than 2 NTU after 26 days of filtration.

  12. Applicability of a novel osmotic membrane bioreactor using a specific draw solution in wastewater treatment.

    PubMed

    Nguyen, Nguyen Cong; Chen, Shiao-Shing; Nguyen, Hau Thi; Ngo, Huu Hao; Guo, Wenshan; Hao, Chan Wen; Lin, Po-Hsun

    2015-06-15

    This study aims to develop a new osmotic membrane bioreactor by combining a moving bed biofilm reactor (MBBR) with forward osmosis membrane bioreactor (FOMBR) to treat wastewater. Ethylenediaminetetraacetic acid disodium salt coupled with polyethylene glycol tert-octylphenyl ether was used as an innovative draw solution in this membrane hybrid system (MBBR-OsMBR) for minimizing the reverse salt flux and maintaining a healthy environment for the microorganism community. The results showed that the hybrid system achieved a stable water flux of 6.94 L/m(2) h and low salt accumulation in the bioreactor for 68 days of operation. At a filling rate of 40% (by volume of the bioreactor) of the polyethylene balls used as carriers, NH4(+)-N and PO4(3-)-P were almost removed (>99%) while producing relatively low NO3(-)-N and NO2(-)-N in the effluent (e.g. <0.56 and 0.96 mg/L, respectively). Furthermore, from analysis based on scanning electron microscopy, Fourier transform infrared spectroscopy, and fluorescence emission-excitation matrix spectrophotometry, there was a thin gel-like fouling layer on the FO membrane, which composed of bacteria as well as biopolymers and protein-like substances. Nonetheless, the formation of these fouling layers of the FO membrane in MBBR-OsMBR was reversible and removed by a physical cleaning technique.

  13. A submerged membrane bioreactor with pendulum type oscillation (PTO) for oily wastewater treatment: membrane permeability and fouling control.

    PubMed

    Qin, Lei; Fan, Zheng; Xu, Lusheng; Zhang, Guoliang; Wang, Guanghui; Wu, Dexin; Long, Xuwei; Meng, Qin

    2015-05-01

    In this study, a novel submerged membrane bioreactor (SMBR) with pendulum type oscillation (PTO) hollow fiber membrane modules was developed to treat oily wastewater and control the problem of membrane fouling. To assess the potential of PTO membrane modules, the effect of oscillation orientation and frequency on membrane permeability was investigated in detail. The forces exerted on sludge flocs in the oscillating SMBR were analyzed to evaluate the impact of membrane oscillating on the cake layer resistance reduction. Results showed that the optimized PTO SMBR system exhibited 11 times higher membrane permeability and better fouling controllability than the conventional MBR system. By hydrodynamic analysis, it was found that the cooperative effect of bubble-induced turbulence and membrane oscillation in PTO SMBR system generated strong shear stress at liquid-membrane interface in vertical and horizontal direction and effectively hindered the particles from depositing on membrane surface.

  14. USE OF MEMBRANE BIOREACTOR FOR BIODEGRADATION OF MTBE IN CONTAMINATED WATER1

    EPA Science Inventory

    An ultrafiltration membrane bioreactor was evaluated for biodegradation of methyl tert-butyl ether (MTBE) in contaminated water. The system was fed 5 mg/L MTBE in granular activated carbon (GAC) treated Cincinnati tap water containing ample buffer and nutrients. Within 120...

  15. Comparative effectiveness of membrane bioreactors, conventional secondary treatment, and disinfection to remove microorganisms from municipal wastewaters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Log removals of bacterial indicators, coliphage, and enteric viruses were studied in three membrane bioreactor activated-sludge (MBR) and two conventional secondary activated-sludge municipal wastewater treatment plants during three disinfection seasons (May–Oct.). In total, 73 regular samples were ...

  16. The role of forward osmosis and microfiltration in an integrated osmotic-microfiltration membrane bioreactor system.

    PubMed

    Luo, Wenhai; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D; Elimelech, Menachem

    2015-10-01

    This study investigates the performance of an integrated osmotic and microfiltration membrane bioreactor (O/MF-MBR) system for wastewater treatment and reclamation. The O/MF-MBR system simultaneously used microfiltration (MF) and forward osmosis (FO) membranes to extract water from the mixed liquor of an aerobic bioreactor. The MF membrane facilitated the bleeding of dissolved inorganic salts and thus prevented the build-up of salinity in the bioreactor. As a result, sludge production and microbial activity were relatively stable over 60 days of operation. Compared to MF, the FO process produced a better permeate quality in terms of nutrients, total organic carbon, as well as hydrophilic and biologically persistent trace organic chemicals (TrOCs). The high rejection by the FO membrane also led to accumulation of hydrophilic and biologically persistent TrOCs in the bioreactor, consequently increasing their concentration in the MF permeate. On the other hand, hydrophobic and readily biodegradable TrOCs were minimally detected in both MF and FO permeates, with no clear difference in the removal efficiencies between two processes.

  17. [Feasibility study on coke wastewater treatment using membrane bioreactor (MBR) system with complete sludge retention].

    PubMed

    Zhao, Wen-Tao; Huang, Xia; Lee, Duu-Jong; He, Miao; Yuan, Yuan

    2009-11-01

    A laboratory-scale submerged anaerobic-anoxic-oxic membrane bioreactor (A1/A2/O-MBR) system was used to treat real coke wastewater and operated continuously for 160 d with complete sludge retention. Pollutants removal performance of the system was investigated through long-term operation. The characteristics of dissolved organic matters (DOMs) in influent and effluent coke wastewater were analyzed using hydrophilic/hydrophobic fractionation, and further discussed based on fluorescence excitation-emission-matrix (EEM). The results showed that A1/A2/O-MBR system could stably remove 88.0% +/- 1.6% of COD, > 99.9% of volatile phenol, 99.4% +/- 0.2% of turbidity, and 98.3% +/- 1.9% of NH4(+) -N, with individual average effluent concentrations of 249 mg/L +/- 44 mg/L, 0.18 mg/L +/- 0.05 mg/L, 1.0 NTU +/- 0.2 NTU and 4.1 mg/L +/- 4.3 mg/L, respectively; moreover, the maximum TN removal rate also reached 74.9%. During the whole operation period, the MLVSS/MLSS appeared to be constant as 90.2% +/- 1.0% and no inorganic matters accumulation occurred. The observed sludge production (MLVSS/COD) decreased with time and stabilized at 0.035 kg/kg. DOMs in coke wastewater were fractionated as hydrophobic acids (HOA), hydrophobic neutrals (HON), hydrophobic bases (HOB) and hydrophilic substances (HIS); HOA was found to be the most abundant constituent in terms of DOC and color intensity both in influent and effluent, which accounted for 70% and 67% of total DOC, and 75% and 76% of total color intensity, respectively. Humic-like substances were suggested to be the major refractory organic and color-causing compounds coke wastewater effluent according to EEM analysis.

  18. Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors.

    PubMed

    Mannina, Giorgio; Capodici, Marco; Cosenza, Alida; Di Trapani, Daniele; Laudicina, Vito Armando; Ødegaard, Hallvard

    2017-02-01

    The present paper reports the results of a nitrous oxide (N2O) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of N2O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production. A significant production of N2O was, however, also found in the anaerobic reactor, thus indicating a probable occurrence of the denitrifying phosphate accumulating organism activity. The highest N2O fluxes were emitted from the aerated reactors (3.09 g N2ON m(-2) h(-1) and 9.87 g N2ON m(-2) h(-1), aerobic and MBR tank, respectively). The emission factor highlighted that only 1% of the total treated nitrogen was emitted from the pilot plant. Furthermore, the measured N2O concentrations in the permeate flow were comparable with other reactors. Nitrous oxide mass balances outlined a moderate production also in the MBR reactor despite the low hydraulic retention time. On the other hand, the mass balance showed that in the aerobic reactor a constant consumption of nitrous oxide (up to almost 15 mg N2O h(-1)) took place, due to the high amount of stripped gas.

  19. Performance and kinetic evaluation of an integrated anaerobic-aerobic bioreactor in the treatment of palm oil mill effluent.

    PubMed

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

    2017-04-01

    This work presents the evaluation of biokinetic coefficients for a novel integrated anaerobic-aerobic bioreactor (IAAB) at different organic loading rates (OLRs) (10.5-22.5 g COD/L per day) treating palm oil mill effluent. The overall efficiencies of the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were more than 99% for OLR up to 19.5 g COD/L day with biogas production containing 48-64% of methane. The effluent quality remained stable (BOD < 80 mg/L) and satisfied with the discharge limit. Stover-Kincannon model was the most appropriate model to estimate the performance of anaerobic compartment of IAAB, while Monod model was best suited for describing the aerobic compartment.

  20. A hybrid microbial fuel cell membrane bioreactor with a conductive ultrafiltration membrane biocathode for wastewater treatment.

    PubMed

    Malaeb, Lilian; Katuri, Krishna P; Logan, Bruce E; Maab, Husnul; Nunes, S P; Saikaly, Pascal E

    2013-10-15

    A new hybrid, air-biocathode microbial fuel cell-membrane bioreactor (MFC-MBR) system was developed to achieve simultaneous wastewater treatment and ultrafiltration to produce water for direct reclamation. The combined advantages of this system were achieved by using an electrically conductive ultrafiltration membrane as both the cathode and the membrane for wastewater filtration. The MFC-MBR used an air-biocathode, and it was shown to have good performance relative to an otherwise identical cathode containing a platinum catalyst. With 0.1 mm prefiltered domestic wastewater as the feed, the maximum power density was 0.38 W/m(2) (6.8 W/m(3)) with the biocathode, compared to 0.82 W/m(2) (14.5 W/m(3)) using the platinum cathode. The permeate quality from the biocathode reactor was comparable to that of a conventional MBR, with removals of 97% of the soluble chemical oxygen demand, 97% NH3-N, and 91% of total bacteria (based on flow cytometry). The permeate turbidity was <0.1 nephelometric turbidity units. These results show that a biocathode MFC-MBR system can achieve high levels of wastewater treatment with a low energy input due to the lack of a need for wastewater aeration.

  1. A novel osmosis membrane bioreactor-membrane distillation hybrid system for wastewater treatment and reuse.

    PubMed

    Nguyen, Nguyen Cong; Nguyen, Hau Thi; Chen, Shiao-Shing; Ngo, Huu Hao; Guo, Wenshan; Chan, Wen Hao; Ray, Saikat Sinha; Li, Chi-Wang; Hsu, Hung-Te

    2016-06-01

    A novel approach was designed to simultaneously enhance nutrient removal and reduce membrane fouling for wastewater treatment using an attached growth biofilm (AGB) integrated with an osmosis membrane bioreactor (OsMBR) system for the first time. In this study, a highly charged organic compound (HEDTA(3-)) was employed as a novel draw solution in the AGB-OsMBR system to obtain a low reverse salt flux, maintain a healthy environment for the microorganisms. The AGB-OsMBR system achieved a stable water flux of 3.62L/m(2)h, high nutrient removal of 99% and less fouling during a 60-day operation. Furthermore, the high salinity of diluted draw solution could be effectively recovered by membrane distillation (MD) process with salt rejection of 99.7%. The diluted draw solution was re-concentrated to its initial status (56.1mS/cm) at recovery of 9.8% after 6h. The work demonstrated that novel multi-barrier systems could produce high quality potable water from impaired streams.

  2. Fiber Attachment Module Experiment (FAME): Using a Multiplexed Miniature Hollow Fiber Membrane Bioreactor Solution for Rapid Process Testing

    NASA Technical Reports Server (NTRS)

    Coutts, Janelle L.; Lunn, Griffin M.; Koss, Lawrence L.; Hummerick, Mary E.; Spencer, Lachelle E.; Johnsey, Marissa N.; Richards, Jeffrey T.; Ellis, Ronald; Birmele, Michele N.; Wheeler, Raymond M.

    2014-01-01

    Bioreactor research is mostly limited to continuous stirred-tank reactors (CSTRs) which are not an option for microgravity (g) applications due to the lack of a gravity gradient to drive aeration as described by the Archimedes principle. Bioreactors and filtration systems for treating wastewater in g could avoid the need for harsh pretreatment chemicals and improve overall water recovery. Solution: Membrane Aerated Bioreactors (MABRs) for g applications, including possible use for wastewater treatment systems for the International Space Station (ISS).

  3. Fractal reconstruction of rough membrane surface related with membrane fouling in a membrane bioreactor.

    PubMed

    Zhang, Meijia; Chen, Jianrong; Ma, Yuanjun; Shen, Liguo; He, Yiming; Lin, Hongjun

    2016-09-01

    In this paper, fractal reconstruction of rough membrane surface with a modified Weierstrass-Mandelbrot (WM) function was conducted. The topography of rough membrane surface was measured by an atomic force microscopy (AFM), and the results showed that the membrane surface was isotropous. Accordingly, the fractal dimension and roughness of membrane surface were calculated by the power spectrum method. The rough membrane surface was reconstructed on the MATLAB platform with the parameter values acquired from raw AFM data. The reconstructed membrane was much similar to the real membrane morphology measured by AFM. The parameters (including average roughness and root mean square (RMS) roughness) associated with membrane morphology for the model and real membrane were calculated, and a good match of roughness parameters between the reconstructed surface and real membrane was found, indicating the feasibility of the new developed method. The reconstructed membrane surface can be potentially used for interaction energy evaluation.

  4. Modeling and simulation of oxygen-limited partial nitritation in a membrane-assisted bioreactor (MBR).

    PubMed

    Wyffels, Stijn; Van Hulle, Stijn W H; Boeckx, Pascal; Volcke, Eveline I P; Van Cleemput, Oswald; Vanrolleghem, Peter A; Verstraete, Willy

    2004-06-05

    Combination of a partial nitritation process and an anaerobic ammonium oxidation process for the treatment of sludge reject water has some general cost-efficient advantages compared to nitrification-denitrification. The integrated process features two-stage autotrophic conversion of ammonium via nitrite to dinitrogen gas with lower demand for oxygen and no external carbon requirement. A nitrifying membrane-assisted bioreactor (MBR) for the treatment of sludge reject water was operated under continuous aeration at low dissolved oxygen (DO) concentrations with the purpose of generating nitrite accumulation. Microfiltration was applied to allow a high sludge retention time (SRT), resulting in a stable partial nitritation process. During start-up of the MBR, oxygen-limited conditions were induced by increasing the ammonium loading rate and decreasing the oxygen transfer. At a loading rate of 0.9 kg N m(-3) d(-1) and an oxygen concentration below 0.1 mg DO L(-1), conversion to nitrite was close to 50% of the incoming ammonium, thereby yielding an optimal effluent within the stoichiometric requirements for subsequent anaerobic ammonium oxidation. A mathematical model for ammonium oxidation to nitrite and nitrite oxidation to nitrate was developed to describe the oxygen-limited partial nitritation process within the MBR. The model was calibrated with in situ determinations of kinetic parameters for microbial growth, reflecting the intrinsic characteristics of the ammonium oxidizing growth system at limited oxygen availability and high sludge age. The oxygen transfer coefficient (K(L)a) and the ammonium-loading rate were shown to be the appropriate operational variables to describe the experimental data accurately. The validated model was used for further steady state simulation under different operational conditions of hydraulic retention time (HRT), K(L)a, temperature and SRT, with the intention to support optimized process design. Simulation results indicated that

  5. Effect of COD/N ratio on nitrogen removal and microbial communities of CANON process in membrane bioreactors.

    PubMed

    Zhang, Xiaojing; Zhang, Hongzhong; Ye, Changming; Wei, Mingbao; Du, Jingjing

    2015-08-01

    In this study, the effect of COD/N ratio on completely autotrophic nitrogen removal over nitrite (CANON) process was investigated in five identical membrane bioreactors. The five reactors were simultaneously seeded for 1L CANON sludge and be operated for more than two months under same conditions, with influent COD/N ratio of 0, 0.5, 1, 2 and 4, respectively. DGGE was used to analyze the microbial communities of aerobic ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AAOB) in five reactors. Results revealed the harmonious work of CANON and denitrification with low COD concentration, whereas too high COD concentration suppressed both AOB and AAOB. AOB and AAOB biodiversity both decreased with COD increasing, which then led to worse nitrogen removal. The suppressing threshold of COD/N ratio for CANON was 1.7. CANON was feasible for treating low COD/N sewage, while the high sewage should be converted by anaerobic biogas producing process in advance.

  6. Conversion of Cn-Unsaturated into Cn-2-Saturated LCFA Can Occur Uncoupled from Methanogenesis in Anaerobic Bioreactors.

    PubMed

    Cavaleiro, Ana J; Pereira, Maria Alcina; Guedes, Ana P; Stams, Alfons J M; Alves, M Madalena; Sousa, Diana Z

    2016-03-15

    Fat, oils, and grease present in complex wastewater can be readily converted to methane, but the energy potential of these compounds is not always recyclable, due to incomplete degradation of long chain fatty acids (LCFA) released during lipids hydrolysis. Oleate (C18:1) is generally the dominant LCFA in lipid-containing wastewater, and its conversion in anaerobic bioreactors results in palmitate (C16:0) accumulation. The reason why oleate is continuously converted to palmitate without further degradation via β-oxidation is still unknown. In this work, the influence of methanogenic activity in the initial conversion steps of unsaturated LCFA was studied in 10 bioreactors continuously operated with saturated or unsaturated C16- and C18-LCFA, in the presence or absence of the methanogenic inhibitor bromoethanesulfonate (BrES). Saturated Cn-2-LCFA accumulated both in the presence and absence of BrES during the degradation of unsaturated Cn-LCFA, and represented more than 50% of total LCFA. In the presence of BrES further conversion of saturated intermediates did not proceed, not even when prolonged batch incubation was applied. As the initial steps of unsaturated LCFA degradation proceed uncoupled from methanogenesis, accumulation of saturated LCFA can be expected. Analysis of the active microbial communities suggests a role for facultative anaerobic bacteria in the initial steps of unsaturated LCFA biodegradation. Understanding this role is now imperative to optimize methane production from LCFA.

  7. Effect of vitamin B12 pulse addition on the performance of cobalt deprived anaerobic granular sludge bioreactors.

    PubMed

    Fermoso, Fernando G; Bartacek, Jan; Lens, Piet N L

    2010-07-01

    The effect of a pulse addition of vitamin B(12) as cobalt source to restore the performance of cobalt depleted methanol-fed bioreactors was investigated. One upflow anaerobic sludge bed (UASB) reactor was supplied with a pulse of vitamin B(12), and its operation was compared to that of another cobalt depleted UASB reactor to which a pulse of CoCl(2) was given. The addition of cobalt in the form of CoCl(2) supplies enough cobalt to restore methanogenesis and maintain full methanol degradation coupled to methane production during more than 35 days after the CoCl(2) pulse. Similar to CoCl(2), pulse addition of vitamin B(12) supplies enough cobalt to maintain full methanol degradation during more than 35 days after the pulse. However, the specific methanogenic activities (SMAs) of the sludge in the vitamin B(12) supplied reactor were around 3 times higher than the SMA of the sludge from the CoCl(2) supplied reactor at the same sampling times. An appropriate dosing strategy (repeated pulse dosing) combined with the choice of vitamin B(12) as the cobalt species is suggested as a promising dosing strategy for methanol-fed anaerobic bioreactors limited by the micronutrient cobalt.

  8. Long term performance of an arsenite-oxidizing-chlorate-reducing microbial consortium in an upflow anaerobic sludge bed (UASB) bioreactor.

    PubMed

    Sun, Wenjie; Sierra-Alvarez, Reyes; Field, Jim A

    2011-04-01

    A chlorate (ClO(3)(-)) reducing microbial consortium oxidized arsenite (As(III)) to arsenate (As(V)) in an upflow anaerobic sludge-bed bioreactor over 550 days operation. As(III) was converted with high conversion efficiencies (>98%) at volumetric loadings ranging from 0.45 to 1.92 mmol As/(L(reactor)d). The oxidation of As(III) was linked to the complete reduction of ClO(3)(-) to Cl(-) and H(2)O, as demonstrated by a molar ratio of approximately 3.0 mol As(III) oxidized per mole of Cl(-) formed and by the greatly lowered ClO(3)(-)-reducing capacity without As(III) feeding. An autotrophic enrichment culture was established from the bioreactor biofilm. A 16S rRNA gene clone library indicated that the culture was dominated by Dechloromonas, and Stenotrophomonas as well as genera within the family Comamonadaceae. The results indicate that the oxidation of As(III) to less mobile As(V) utilizing ClO(3)(-) as a terminal electron acceptor provides a sustainable bioremediation strategy for arsenic contamination in anaerobic environments.

  9. Effect of oxygen partial pressure and chemical oxygen demand loading on the biofilm properties in membrane-aerated bioreactors.

    PubMed

    Zhu, I X; Alien, D G; Liss, S N

    2009-03-01

    Membrane-aerated biofilms with oxygen and nutrients diffusing from the opposite sides possess distinct properties, including the ability to couple aerobic and anaerobic processes. The objective of this study was to examine the effects of oxygen partial pressure and chemical oxygen demand (COD) loading on biofilm properties. Two laboratory-scale membrane-aerated bioreactors were operated for a total of 283 days, with one reactor operated at 42, 60, and 89 kPa (0.41, 0.59, and 0.88 atm) oxygen, and the other reactor at 25 kPa (0.25 atm) oxygen (air control). The biofilm detached at the oxygen partial pressures of 60 and 89 kPa (0.59 and 0.88 atm) at a COD loading of 11.3 kg COD/1000 m2/d, but was sustained at the oxygen partial pressures of 25 and 42 kPa (0.25 and 0.41 atm), with a porous structure at the membrane interface at the COD loading of 11.3 kg COD/1000 m2/d. Biofilm formation was improved at a higher COD loading. It is proposed that the loss of extracellular polymeric substances at the biofilm bottom is the cause for the biofilm detachment subjected to a higher oxygen partial pressure.

  10. Long-term study on the impact of temperature on enhanced biological phosphorus and nitrogen removal in membrane bioreactor.

    PubMed

    Sayi-Ucar, N; Sarioglu, M; Insel, G; Cokgor, E U; Orhon, D; van Loosdrecht, M C M

    2015-11-01

    The study involved experimental observation and performance evaluation of a membrane bioreactor system treating municipal wastewater for nutrient removal for a period 500 days, emphasizing the impact of high temperature on enhanced biological phosphorus removal (EBPR). The MBR system was operated at relatively high temperatures (24-41 °C). During the operational period, the total phosphorus (TP) removal gradually increased from 50% up to 95% while the temperature descended from 41 to 24 °C. At high temperatures, anaerobic volatile fatty acid (VFA) uptake occurred with low phosphorus release implying the competition of glycogen accumulating organisms (GAOs) with polyphosphate accumulating organisms (PAOs). Low dissolved oxygen conditions associated with high wastewater temperatures did not appreciable affected nitrification but enhanced nitrogen removal. Dissolved oxygen levels around 1.0 mgO2/L in membrane tank provided additional denitrification capacity of 6-7 mgN/L by activating simultaneous nitrification and denitrification. As a result, nearly complete removal of nitrogen could be achieved in the MBR system, generating a permeate with no appreciable nitrogen content. The gross membrane flux was 43 LMH corresponding to the specific permeability (K) of 413 LMH/bar at 39 °C in the MBR tank. The specific permeability increased by the factor of 43% at 39 °C compared to that of 25 °C during long-term operation.

  11. Membrane Bioreactor Technology for the Development of Functional Materials from Sea-Food Processing Wastes and Their Potential Health Benefits

    PubMed Central

    Kim, Se-Kwon; Senevirathne, Mahinda

    2011-01-01

    Sea-food processing wastes and underutilized species of fish are a potential source of functional and bioactive compounds. A large number of bioactive substances can be produced through enzyme-mediated hydrolysis. Suitable enzymes and the appropriate bioreactor system are needed to incubate the waste materials. Membrane separation is a useful technique to extract, concentrate, separate or fractionate the compounds. The use of membrane bioreactors to integrate a reaction vessel with a membrane separation unit is emerging as a beneficial method for producing bioactive materials such as peptides, chitooligosaccharides and polyunsaturated fatty acids from diverse seafood-related wastes. These bioactive compounds from membrane bioreactor technology show diverse biological activities such as antihypertensive, antimicrobial, antitumor, anticoagulant, antioxidant and radical scavenging properties. This review discusses the application of membrane bioreactor technology for the production of value-added functional materials from sea-food processing wastes and their biological activities in relation to health benefits. PMID:24957872

  12. Microbial Transformation of Biomacromolecules in a Membrane Bioreactor: Implications for Membrane Fouling Investigation

    PubMed Central

    Zhou, Zhongbo; Meng, Fangang; Chae, So-Ryong; Huang, Guocheng; Fu, Wenjie; Jia, Xiaoshan; Li, Shiyu; Chen, Guang-Hao

    2012-01-01

    Background The complex characteristics and unclear biological fate of biomacromolecules (BMM), including colloidal and soluble microbial products (SMP), extracellular polymeric substances (EPS) and membrane surface foulants (MSF), are crucial factors that limit our understanding of membrane fouling in membrane bioreactors (MBRs). Findings In this study, the microbial transformation of BMM was investigated in a lab-scale MBR by well-controlled bioassay tests. The results of experimental measurements and mathematical modeling show that SMP, EPS, and MSF had different biodegradation behaviors and kinetic models. Based on the multi-exponential G models, SMP were mainly composed of slowly biodegradable polysaccharides (PS), proteins (PN), and non-biodegradable humic substances (HS). In contrast, EPS contained a large number of readily biodegradable PN, slowly biodegradable PS and HS. MSF were dominated by slowly biodegradable PS, which had a degradation rate constant similar to that of SMP-PS, while degradation behaviors of MSF-PN and MSF-HS were much more similar to those of EPS-PN and EPS-HS, respectively. In addition, the large-molecular weight (MW) compounds (>100 kDa) in BMM were found to have a faster microbial transformation rate compared to the small-MW compounds (<5 kDa). The parallel factor (PARAFAC) modeling of three-dimensional fluorescence excitation-emission matrix (EEM) spectra showed that the tryptophan-like PN were one of the major fractions in the BMM and they were more readily biodegradable than the HS. Besides microbial mineralization, humification and hydrolysis could be viewed as two important biotransformation mechanisms of large-MW compounds during the biodegradation process. Significance The results of this work can aid in tracking the origin of membrane foulants from the perspective of the biotransformation behaviors of SMP, EPS, and MSF. PMID:22912694

  13. Bacteriophage therapy for membrane biofouling in membrane bioreactors and antibiotic-resistant bacterial biofilms.

    PubMed

    Bhattacharjee, Ananda Shankar; Choi, Jeongdong; Motlagh, Amir Mohaghegh; Mukherji, Sachiyo T; Goel, Ramesh

    2015-08-01

    To demonstrate elimination of bacterial biofilm on membranes to represent wastewater treatment as well as biofilm formed by antibiotic-resistant bacterial (ARB) to signify medical application, an antibiotic-resistant bacterium and its lytic bacteriophage were isolated from a full-scale wastewater treatment plant. Based on gram staining and complete 16 S rDNA sequencing, the isolated bacterium showed a more than 99% homology with Delftia tsuruhatensis, a gram-negative bacterium belonging to β-proteobacteria. The Delftia lytic phage's draft genome revealed the phage to be an N4-like phage with 59.7% G + C content. No transfer RNAs were detected for the phage suggesting that the phage is highly adapted to its host Delftia tsuruhatensis ARB-1 with regard to codon usage, and does not require additional tRNAs of its own. The gene annotation of the Delftia lytic phage found three different components of RNA polymerase (RNAP) in the genome, which is a typical characteristic of N4-like phages. The lytic phage specific to D. tsuruhatensis ARB-1 could successfully remove the biofilm formed by it on a glass slide. The water flux through the membrane of a prototype lab-scale membrane bioreactor decreased from 47 L/h m(2) to ∼15 L/h m(2) over 4 days due to a biofilm formed by D. tsuruhatensis ARB-1. However, the flux increased to 70% of the original after the lytic phage application. Overall, this research demonstrated phage therapy's great potential to solve the problem of membrane biofouling, as well as the problems posed by pathogenic biofilms in external wounds and on medical instruments.

  14. Osmotic versus conventional membrane bioreactors integrated with reverse osmosis for water reuse: Biological stability, membrane fouling, and contaminant removal.

    PubMed

    Luo, Wenhai; Phan, Hop V; Xie, Ming; Hai, Faisal I; Price, William E; Elimelech, Menachem; Nghiem, Long D

    2017-02-01

    This study systematically compares the performance of osmotic membrane bioreactor - reverse osmosis (OMBR-RO) and conventional membrane bioreactor - reverse osmosis (MBR-RO) for advanced wastewater treatment and water reuse. Both systems achieved effective removal of bulk organic matter and nutrients, and almost complete removal of all 31 trace organic contaminants investigated. They both could produce high quality water suitable for recycling applications. During OMBR-RO operation, salinity build-up in the bioreactor reduced the water flux and negatively impacted the system biological treatment by altering biomass characteristics and microbial community structure. In addition, the elevated salinity also increased soluble microbial products and extracellular polymeric substances in the mixed liquor, which induced fouling of the forward osmosis (FO) membrane. Nevertheless, microbial analysis indicated that salinity stress resulted in the development of halotolerant bacteria, consequently sustaining biodegradation in the OMBR system. By contrast, biological performance was relatively stable throughout conventional MBR-RO operation. Compared to conventional MBR-RO, the FO process effectively prevented foulants from permeating into the draw solution, thereby significantly reducing fouling of the downstream RO membrane in OMBR-RO operation. Accumulation of organic matter, including humic- and protein-like substances, as well as inorganic salts in the MBR effluent resulted in severe RO membrane fouling in conventional MBR-RO operation.

  15. Performance assessment of a pilot-size vacuum rotation membrane bioreactor treating urban wastewater

    NASA Astrophysics Data System (ADS)

    Alnaizy, Raafat; Aidan, Ahmad; Luo, Haonan

    2011-12-01

    This study investigated the suitability and performance of a pilot-scale membrane bioreactor (MBR). Huber vacuum rotation membrane (VRM 20/36) bioreactor was installed at the Sharjah sewage treatment plant (STP) in the United Arab Emirate for 12 months. The submerged membranes were flat sheets with a pore size of 0.038 μm. The VRM bioreactor provided a final effluent of very high quality. The average reduction on parameters such as COD was from 620 to 3 mg/l, BOD from 239 to 3 mg/l, Ammonia from 37 to 2 mg/l, turbidity from 225NTU to less than 3NTU, and total suspended solids from 304 mg/l to virtually no suspended solids. The rotating mechanism of the membrane panels permitted the entire membrane surface to receive the same intensive degree of air scouring, which lead to a longer duration. The MBR process holds a promising future because of its smaller footprints in contrast to conventional systems, superior effluent quality, and high loading rate capacity.

  16. Evaluation of different configurations of hybrid membrane bioreactors for treatment of domestic wastewater.

    PubMed

    Cuevas-Rodríguez, G; Cervantes-Avilés, P; Torres-Chávez, I; Bernal-Martínez, A

    2015-01-01

    Four membrane bioreactors (MBRs) with the same dimensions were studied for 180 days: three hybrid growth membrane bioreactors with biofilm attached in different packing media and a conventional MBR (C-MBR). The four MBRs had an identical membrane module of hollow fiber with a nominal porous diameter of 0.4 μm. The MBRs were: (1) a C-MBR; (2) a moving bed membrane bioreactor (MB-MBR), which was packed with 2 L of carrier Kaldnes-K1, presenting an exposed surface area of 678.90 m²/m³; (3) a non-submerged organic fixed bed (OFB-MBR) packed with 6.5 L of organic packing media composed of a mixture of cylindrical pieces of wood, providing an exposed surface area of 178.05 m²/m³; and (4) an inorganic fixed bed non-submerged membrane bioreactor (IFB-MBR) packed with 6 L of spherical volcanic pumice stone with an exposed surface area of 526.80 m²/m³. The four MBRs were fed at low organic loading (0.51 ± 0.19 kgCOD/m³ d). The results were recorded according to the behavior of the total resistance, transmembrane pressure (TMP), permeability, and removal percentages of the nutrients during the experimental time. The results showed that the MB-MBR presented the better performance on membrane filtration, while the higher nutrient removals were detected in the OFB-MBR and IFB-MBR.

  17. Use of inhibitory solvents in multi-membrane bioreactor

    NASA Technical Reports Server (NTRS)

    Cho, Toohyon (Inventor); Shuler, Michael L. (Inventor)

    1990-01-01

    An immobilized liquid membrane is employed to allow use of a product-extracting solvent which is normally toxic toward a cell layer which produces the product in a membrane-moderated biological reaction.

  18. Removal of pharmaceuticals from synthetic wastewater in an aerobic granular sludge membrane bioreactor and determination of the bioreactor microbial diversity.

    PubMed

    Wang, Xiao-Chun; Shen, Ji-Min; Chen, Zhong-Lin; Zhao, Xia; Xu, Hao

    2016-09-01

    Five types of pharmaceuticals and personal care products (PPCPs) substances were selected as pollutants in this study. The effects of the removal of these pollutants and the microbial succession process in a granular sludge membrane bioreactor (GMBR) were investigated. Results showed that wastewater containing PPCPs influenced the performance of granular sludge. The removal of the five PPCPs from the GMBR had different effects. The removal rates of prednisolone, norfloxacin and naproxen reached 98.5, 87.8 and 84 %, respectively. The degradation effect in the GMBR system was relatively lower for sulphamethoxazole and ibuprofen, with removal efficiency rates of 79.8 and 63.3 %, respectively. Furthermore, the microbial community structure and diversity variation of the GMBR were analysed via high-throughput sequencing technology. The results indicated the structural and functional succession of the microbial community based on the GMBR process. The results indicate the key features of bacteria with an important role in drug degradation.

  19. An ecology-based analysis of irreversible biofouling in membrane bioreactors.

    PubMed

    Zhang, K; Choi, H; Wu, M; Sorial, G A; Dionysiou, D; Oerther, D B

    2007-01-01

    To provide the first step towards a microbial ecology-based understanding of irreversible membrane biofouling, four laboratory-scale membrane bioreactors (MBRs) were operated to investigate the identity of bacterial populations highly correlated with irreversible membrane biofouling. The conventional MBR was divided into two separate experimental units. Unit one consisted of four suspended-growth, activated sludge, sequencing batch bioreactors treating a synthetic paper mill wastewater. Unit two consisted of a microfiltration membrane cell. Amplified ribosomal deoxyribonucleic acid restriction analysis (ARDRA) was used to compare the predominant bacterial populations in samples of mixed liquor and irreversibly bound to the membrane surface. The results of ARDRA showed a significant difference between the planktonic and sessile bacterial communities suggesting that irreversible biofouling of microfiltration membranes may be more highly correlated to specific bacterial populations rather than the total, bulk concentration of biomass. A custom-built mini-flow cell and light microscopy were used to visualise the early formation of biofilms by two pure cultures (Escherichia coli and Acinetobacter calcoaceticus) on membrane surfaces. The results confirmed that A. calcoaceticus was able to enhance the initiation of biofilm formation on microfiltration membranes.

  20. Real-time monitoring of biofoulants in a membrane bioreactor during saline wastewater treatment for anti-fouling strategies.

    PubMed

    Tan, Songwen; Hou, Yang; Cui, Chunzhi; Chen, Xuncai; Li, Weiguo

    2017-01-01

    This work presents a novel, fast and simple monitoring-responding method at the very early stages of membrane bio-fouling in a membrane bioreactor (MBR) during saline wastewater treatment. The impacts of multiple environmental shocks on membrane fouling were studied. The transmembrane pressure exceeded the critical fouling pressure within 8days in the case of salinity shock or temperature shock. In the case of DO shock, the transmembrane pressure exceeded the critical fouling pressure after 16days, showing the lower impact of DO shock on the MBR. In another study, the membrane fouling was observed within 4days responding to mixed environmental shocks. To decrease the potential of membrane bio-fouling, another bioreactor was integrated immediately with the MBR as a quickly-responded countermeasure, when an early warning of membrane bio-fouling was provided. After the bioreactor enhancement, the time required for membrane fouling increased from 4 to 10days.

  1. Model system studies with a phase separated membrane bioreactor

    NASA Technical Reports Server (NTRS)

    Petersen, G. R.; Seshan, P. K.; Dunlop, Eric H.

    1989-01-01

    The operation and evaluation of a bioreactor designed for high intensity oxygen transfer in a microgravity environment is described. The reactor itself consists of a zero headspace liquid phase separated from the air supply by a long length of silicone rubber tubing through which the oxygen diffuses in and the carbon dioxide diffuses out. Mass transfer studies show that the oxygen is film diffusion controlled both externally and internally to the tubing and not by diffusion across the tube walls. Methods of upgrading the design to eliminate these resistances are proposed. Cell growth was obtained in the fermenter using Saccharomyces cerevisiae showing that this concept is capable of sustaining cell growth in the terrestial simulation.

  2. Phase separated membrane bioreactor - Results from model system studies

    NASA Technical Reports Server (NTRS)

    Petersen, G. R.; Seshan, P. K.; Dunlop, E. H.

    1989-01-01

    The operation and evaluation of a bioreactor designed for high intensity oxygen transfer in a microgravity environment is described. The reactor itself consists of a zero headspace liquid phase separated from the air supply by a long length of silicone rubber tubing through which the oxygen diffuses in and the carbon dioxide diffuses out. Mass transfer studies show that the oxygen is film diffusion controlled both externally and internally to the tubing and not by diffusion across the tube walls. Methods of upgrading the design to eliminate these resistances are proposed. Cell growth was obtained in the fermenter using Saccharomyces cerevisiae showing that this concept is capable of sustaining cell growth in the terrestrial simulation.

  3. Phase separated membrane bioreactor: results from model system studies.

    PubMed

    Petersen, G R; Seshan, P K; Dunlop, E H

    1989-01-01

    The operation and evaluation of a bioreactor designed for high intensity oxygen transfer in a microgravity environment is described. The reactor itself consists of a zero headspace liquid phase separated from the air supply by a long length of silicone rubber tubing through which the oxygen diffuses in and the carbon dioxide diffuses out. Mass transfer studies show that the oxygen is film diffusion controlled both externally and internally to the tubing and not by diffusion across the tube walls. Methods of upgrading the design to eliminate these resistances are proposed. Cell growth was obtained in the fermenter using Saccharomyces cerevisiae showing that this concept is capable of sustaining cell growth in the terrestrial [correction of terrestial] simulation.

  4. Molecular-based detection of potentially pathogenic bacteria in membrane bioreactor (MBR) systems treating municipal wastewater: a case study.

    PubMed

    Harb, Moustapha; Hong, Pei-Ying

    2017-02-01

    Although membrane bioreactor (MBR) systems provide better removal of pathogens compared to conventional activated sludge processes, they do not achieve total log removal. The present study examines two MBR systems treating municipal wastewater, one a full-scale MBR plant and the other a lab-scale anaerobic MBR. Both of these systems were operated using microfiltration (MF) polymeric membranes. High-throughput sequencing and digital PCR quantification were utilized to monitor the log removal values (LRVs) of associated pathogenic species and their abundance in the MBR effluents. Results showed that specific removal rates vary widely regardless of the system employed. Each of the two MBR effluents' microbial communities contained genera associated with opportunistic pathogens (e.g., Pseudomonas, Acinetobacter) with a wide range of log reduction values (< 2 to >5.5). Digital PCR further confirmed that these bacterial groups included pathogenic species, in several instances at LRVs different than those for their respective genera. These results were used to evaluate the potential risks associated both with the reuse of the MBR effluents for irrigation purposes and with land application of the activated sludge from the full-scale MBR system.

  5. Effects of hydraulic retention time and bioflocculant addition on membrane fouling in a sponge-submerged membrane bioreactor.

    PubMed

    Deng, Lijuan; Guo, Wenshan; Ngo, Huu Hao; Du, Bing; Wei, Qin; Tran, Ngoc Han; Nguyen, Nguyen Cong; Chen, Shiao-Shing; Li, Jianxin

    2016-06-01

    The characteristics of activated sludge and membrane fouling were evaluated in a sponge-submerged membrane bioreactor (SSMBR) at different hydraulic retention times (HRTs) (6.67, 5.33 and 4.00h). At shorter HRT, more obvious membrane fouling was caused by exacerbated cake layer formation and aggravated pore blocking. Activated sludge possessed more extracellular polymeric substances (EPS) due to excessive growth of biomass and lower protein to polysaccharide ratio in soluble microbial products (SMP). The cake layer resistance was aggravated by increased sludge viscosity together with the accumulated EPS and biopolymer clusters (BPC) on membrane surface. However, SMP showed marginal effect on membrane fouling when SSMBRs were operated at all HRTs. The SSMBR with Gemfloc® addition at the optimum HRT of 6.67h demonstrated superior sludge characteristics such as larger floc size, less SMP in mixed liquor with higher protein/polysaccharide ratio, less SMP and BPC in cake layer, thereby further preventing membrane fouling.

  6. Long-term effect on membrane fouling in a new membrane bioreactor as a pretreatment to seawater desalination.

    PubMed

    Jeong, Sanghyun; Rice, Scott A; Vigneswaran, Saravanamuthu

    2014-08-01

    Submerged membrane adsorption bio-reactors (SMABR) were investigated as a new pretreatment for seawater reverse osmosis (SWRO) desalination. They were tested with different doses of powder activated carbon (PAC) on-site for a long-term. The biofouling on the membrane was assessed in terms of DNA (cells) and polysaccharide distribution. MBR without PAC addition resulted in severe fouling on membrane. When PAC is added in the MBR, PAC could reduce the organic fouling. Hence the biofilm formation on membrane was reduced without any membrane damage. PAC also helped to remove low molecular weight (LMW) organics responsible for biofouling of RO membrane. A linear correlation between assimilable organic carbon (AOC) and LMW organics was observed. A small amount of PAC (2.4-8.0g of PAC/m(3) of seawater) was sufficient to reduce biofouling. It indicated that SMABR is an environmentally-friendly biological pretreatment to reduce biofouling for SWRO.

  7. Membrane fouling in a membrane bioreactor: High filtration resistance of gel layer and its underlying mechanism.

    PubMed

    Chen, Jianrong; Zhang, Meijia; Li, Fengquan; Qian, Lei; Lin, Hongjun; Yang, Lining; Wu, Xilin; Zhou, Xiaoling; He, Yiming; Liao, Bao-Qiang

    2016-10-01

    A membrane bioreactor (MBR) was continuously operated to investigate mechanisms of fouling caused by the gel layer in this study. Agar was used as a model foulant for gel layer formation, and filtration resistance of gel layers was systematically assessed. The results showed that gel layer possessed unusually high specific filtration resistance (SFR) and high measured porosity as compared with cake layer. Current knowledge cannot explain the contradiction between high filtration resistance and high porosity of gel layer. A new fouling mechanism based on Flory-Huggins theory was then proposed. Filtration resistance of agar gel layer was found to be independent of pH and ionic strength, but linearly increase with gel thickness. The results are accordant with the mechanism deductions. Simulation of the mechanism model showed that the filtration resistance induced by mixing chemical potential variation was comparable to the experimental data of filtration resistance of agar gel layer, indicating that the proposed mechanism is the predominant mechanism responsible for the high filtration resistance of gel layer. The proposed mechanism was further verified from the bound water viewpoint.

  8. Effects of flux enhancing polymer on the characteristics of sludge in membrane bioreactor process.

    PubMed

    Yoon, S H; Collins, J H; Musale, D; Sundararajan, S; Tsai, S P; Hallsby, G A; Kong, J F; Koppes, J; Cachia, P

    2005-01-01

    A newly developed membrane performance enhancer (MPE) was used to prevent membrane fouling in a membrane bioreactor (MBR) process. It transpired that 1,000 mg/l of MPE reduced polysaccharide levels from 41 mg/I to 21 mg/I on average under the experimental condition. Repeated experiments also confirmed that 50-1,000 mg/l of MPE could reduce membrane fouling significantly and increase the intervals between membrane cleanings. Depending on MPE dosages and experimental conditions, trans-membrane pressure (TMP) increase was suppressed for 20-30 days, while baseline TMP surged within a few days. In addition, MPE allowed MBR operation even at 50,000 mg/l of total solid and reduced permeate COD. However, no evidence of toxicity for sludge was found from respiratory works.

  9. Microbial Relevant Fouling in Membrane Bioreactors: Influencing Factors, Characterization, and Fouling Control

    PubMed Central

    Wu, Bing; Fane, Anthony G.

    2012-01-01

    Microorganisms in membrane bioreactors (MBRs) play important roles on degradation of organic/inorganic substances in wastewaters, while microbial deposition/growth and microbial product accumulation on membranes potentially induce membrane fouling. Generally, there is a need to characterize membrane foulants and to determine their relations to the evolution of membrane fouling in order to identify a suitable fouling control approach in MBRs. This review summarized the factors in MBRs that influence microbial behaviors (community compositions, physical properties, and microbial products). The state-of-the-art techniques to characterize biofoulants in MBRs were reported. The strategies for controlling microbial relevant fouling were discussed and the future studies on membrane fouling mechanisms in MBRs were proposed. PMID:24958297

  10. Hydrodynamic optimization of membrane bioreactor by horizontal geometry modification using computational fluid dynamics.

    PubMed

    Yan, Xiaoxu; Wu, Qing; Sun, Jianyu; Liang, Peng; Zhang, Xiaoyuan; Xiao, Kang; Huang, Xia

    2016-01-01

    Geometry property would affect the hydrodynamics of membrane bioreactor (MBR), which was directly related to membrane fouling rate. The simulation of a bench-scale MBR by computational fluid dynamics (CFD) showed that the shear stress on membrane surface could be elevated by 74% if the membrane was sandwiched between two baffles (baffled MBR), compared with that without baffles (unbaffled MBR). The effects of horizontal geometry characteristics of a bench-scale membrane tank were discussed (riser length index Lr, downcomer length index Ld, tank width index Wt). Simulation results indicated that the average cross flow of the riser was negatively correlated to the ratio of riser and downcomer cross-sectional area. A relatively small tank width would also be preferable in promoting shear stress on membrane surface. The optimized MBR had a shear elevation of 21.3-91.4% compared with unbaffled MBR under same aeration intensity.

  11. Development of a novel Submerged Membrane Electro-Bioreactor (SMEBR): performance for fouling reduction.

    PubMed

    Bani-Melhem, Khalid; Elektorowicz, Maria

    2010-05-01

    A novel Submerged Membrane Electro-Bioreactor (SMEBR) was developed to treat wastewater and control the problem of membrane fouling. To validate the new design, experimental work was achieved in a few phases. This paper describes the design constraints and criteria of the new developed SMEBR system, and shows the results of the performance of the SMEBR system to reduce membrane fouling when intermittent direct current (DC) (15 min ON/45 min OFF) was applied using cylindrical iron mesh for both electrodes. Application of the SMEBR system enhanced the membrane filterability by reducing the fouling rate up to 16.3% without any backwashing of the membrane module. The improvement in membrane filterability associated with a decrease in zeta potential of the mixed liquor flocs from -30.5 up to -15.3 mV and a decrease in specific resistance to filtration (SRF) up to 40% was observed.

  12. Measuring the activity of heterotrophic microorganism in membrane bioreactor for drinking water treatment.

    PubMed

    Han, Zheng-Shuang; Tian, Jia-Yu; Liang, Heng; Ma, Jun; Yu, Hua-Rong; Li, Kai; Ding, An; Li, Gui-Bai

    2013-02-01

    In order to quantify the activity of heterotrophic microorganism in membrane bioreactor (MBR) for drinking water treatment, biomass respiration potential (BRP) test and 2,3,5-triphenyl tetrazolium chloride-dehydrogenase activity (TTC-DHA) test were introduced and modified. A sludge concentration ratio of 5:1, incubation time of 2h, an incubation temperature that was close to the real operational temperature, and using a mixture of main AOC components as the substrate were adopted as the optimum parameters for determination of DHA in drinking water MBR. A remarkable consistency among BDOC removal, BRP and DHA for assessing biological performance in different MBRs was achieved. Moreover, a significant correlation between the BRP and DHA results of different MBRs was obtained. However, the TTC-DHA test was expected to be inaccurate for quantifying the biomass activity in membrane adsorption bioreactor (MABR), while the BRP test turned out to be still feasible in that case.

  13. Optimal operating policy of the ultrafiltration membrane bioreactor for enzymatic hydrolysis of cellulose

    SciTech Connect

    Lee, SeungGoo; Kim, HakSung . Dept. of Biotechnology)

    1993-09-05

    The dilution rate of an ultrafiltration membrane bioreactor in the enzymatic hydrolysis of cellulose was optimized using the kinetic model developed by Fan and Lee.' The sequence of optimal dilution rates was found to generally consist of an initial period of a minimal value (batch period), a subsequent period of maximum dilution rate, a period of a second batch, and a final period of a singular dilution rate. The effects of operating conditions, such as [beta]-glucosidase activity, operating time, maximum dilution rate, substrate feeding rate, and enzyme-to-substrate ratio on both the conversion yield and the sequence of optimal dilution rates were investigated. To evaluate the validity of kinetic model employed in this work, enzymatic hydrolysis was carried out using -cellulose as a substrate in the ultrafiltration membrane bioreactor. The experimental data were well consistent with the simulation results.

  14. A novel application of an anaerobic membrane process in wastewater treatment.

    PubMed

    You, H S; Tseng, C C; Peng, M J; Chang, S H; Chen, Y C; Peng, S H

    2005-01-01

    The applications of membrane processes in anaerobic biological wastewater treatment still have some limitations due to severe membrane scaling and fouling, although they have been proven to achieve superior COD removal and biomass retention. An innovative anaerobic membrane process for wastewater treatment was conducted to control the membrane scaling problems. The process comprises an anaerobic reactor, an aerobic reactor, and a membrane separation tank. Anaerobic sludge from a full-scale UASB reactor treating food wastewater was inoculated to anaerobic and aerobic reactor to purify synthetic wastewater consisting of glucose and sodium acetate. The anaerobic reactor was operated in a sludge bed type without three-phase separator. The aerobic reactor can eliminate residual organics from the anaerobic reactor effluent using facultative microorganisms. To provide solid-liquid separation, hollow fiber ultrafiltration module was submerged in the separation tank. The results clearly show that the anaerobic membrane process combined methanogenic and aerobic COD reduction is a stable system. No fatal scaling was found after two months of operation even without chemical cleaning for the membrane. It was also found that inorganic precipitates formed in the aerobic reactor were reduced due to CO2 stripping in aerobic reactor. Another important finding was that the inorganic precipitates were entrapped into facultative aerobes floc. The ash/SS ratio of aerobes floc increased from 0.17 to 0.55 after 50 days of operation, which confirms this phenomenon. Based on our investigation, the new process can control scaling effectively to extend the membrane application in anaerobic treatment.

  15. Membrane bioreactor technology: A novel approach to the treatment of compost leachate

    SciTech Connect

    Brown, Kayleigh; Ghoshdastidar, Avik J.; Hanmore, Jillian; Frazee, James; Tong, Anthony Z.

    2013-11-15

    Highlights: • First membrane bioreactor treatment method for compost leachate. • No chemical additive or UV radiation source in this new biological method. • Removal rates of more than 99% for organics and ammonium were achieved. • Heavy metals were reduced by at least 82.7% except copper. - Abstract: Compost leachate forms during the composting process of organic material. It is rich in oxidizable organics, ammonia and metals, which pose a risk to the environment if released without proper treatment. An innovative method based on the membrane bioreactor (MBR) technology was developed to treat compost leachate over 39 days. Water quality parameters, such as pH, dissolved oxygen, ammonia, nitrate, nitrite and chemical oxygen demand (COD) were measured daily. Concentrations of caffeine and metals were measured over the course of the experiment using gas chromatography – mass spectrometry (GC/MS) and inductively coupled plasma – mass spectrometry (ICP–MS) respectively. A decrease of more than 99% was achieved for a COD of 116 g/L in the initial leachate. Ammonia was decreased from 2720 mg/L to 0.046 mg/L, while the nitrate concentration in the effluent rose to 710 mg/L. The bacteria in the MBR system adjusted to the presence of the leachate, and increased 4 orders of magnitude. Heavy metals were removed by at least 82.7% except copper. These successful results demonstrated the membrane bioreactor technology is feasible, efficient method for the treatment of compost leachate.

  16. Phosphorus and water recovery by a novel osmotic membrane bioreactor-reverse osmosis system.

    PubMed

    Luo, Wenhai; Hai, Faisal I; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2016-01-01

    An osmotic membrane bioreactor-reverse osmosis (OMBR-RO) hybrid system integrated with periodic microfiltration (MF) extraction was evaluated for simultaneous phosphorus and clean water recovery from raw sewage. In this hybrid system, the forward osmosis membrane effectively retained inorganic salts and phosphate in the bioreactor, while the MF membrane periodically bled them out for phosphorus recovery with pH adjustment. The RO process was used for draw solute recovery and clean water production. Results show that phosphorus recuperation from the MF permeate was most effective when the solution pH was adjusted to 10, whereby the recovered precipitate contained 15-20% (wt/wt) of phosphorus. Periodic MF extraction also limited salinity build-up in the bioreactor, resulting in a stable biological performance and an increase in water flux during OMBR operation. Despite the build-up of organic matter and ammonia in the draw solution, OMBR-RO allowed for the recovery of high quality reused water.

  17. Ion exchange membrane bioreactor for treating groundwater contaminated with high perchlorate concentrations.

    PubMed

    Fox, Shalom; Oren, Yoram; Ronen, Zeev; Gilron, Jack

    2014-01-15

    Perchlorate contamination of groundwater is a worldwide concern. The most cost efficient treatment for high concentrations is biological treatment. In order to improve and increase the acceptance of this treatment, there is a need to reduce the contact between micro organisms in the treatment unit and the final effluent. An ion exchange membrane bioreactor (IEMB), in which treated water is separated from the bioreactor, was suggested for this purpose. In this study, the IEMB's performance was studied at a concentration as high as 250mgL(-1) that were never studied before. In the bioreactor, glycerol was used as a low cost and nontoxic carbon and energy source for the reduction of perchlorate to chloride. We found that high perchlorate concentrations in the feed rendered the anion exchange membrane significantly less permeable to perchlorate. However, the presence of bacteria in the bio-compartment significantly increased the flux through the membrane by more than 25% in comparison to pure Donnan dialysis. In addition, the results suggested minimal secondary contamination (<3mgCL(-1)) of the treated water with the optimum feed of carbon substrate. Our results show that IEMB can efficiently treat groundwater contaminated with perchlorate as high as 250mgL(-1).

  18. Influences of acid-base property of membrane on interfacial interactions related with membrane fouling in a membrane bioreactor based on thermodynamic assessment.

    PubMed

    Zhao, Leihong; Qu, Xiaolu; Zhang, Meijia; Lin, Hongjun; Zhou, Xiaoling; Liao, Bao-Qiang; Mei, Rongwu; Hong, Huachang

    2016-08-01

    Failure of membrane hydrophobicity in predicting membrane fouling requires a more reliable indicator. In this study, influences of membrane acid base (AB) property on interfacial interactions in two different interaction scenarios in a submerged membrane bioreactor (MBR) were studied according to thermodynamic approaches. It was found that both the polyvinylidene fluoride (PVDF) membrane and foulant samples in the MBR had relatively high electron donor (γ(-)) component and low electron acceptor (γ(+)) component. For both of interaction scenarios, AB interaction was the major component of the total interaction. The results showed that, the total interaction monotonically decreased with membrane γ(-), while was marginally affected by membrane γ(+), suggesting that γ(-) could act as a reliable indicator for membrane fouling prediction. This study suggested that membrane modification for fouling mitigation should orient to improving membrane surface γ(-) component rather than hydrophilicity.

  19. Membrane bioreactor process of organic wastewater from brassylic acid manufacturing plant.

    PubMed

    Wu, Z C; Zeng, P; Wang, S F; Gao, T Y

    2001-04-01

    The wastewater treatment from brassylic acid manufacturing plant using membrane bioreactor (MBR) was studied. The membrane bioreactor consisted of batch-operation biological aeration tank and ultrafiltration evaluation tank. The content of test included the affection of variation operation conditions on ultrafiltration separation, the general characteristics of MBR process, and the difference comparing with the conventional biological treatment. The results are as follows: (1) among the test membrane material, polyether sulphone (PES) membrane is more suitable for the wastewater treatment; (2) when the cutoff molecular weight is among 10,000-50,000, the higher the cutoff molecular weight, the bigger the water flux is in the test; (3) under the operation pressure, water flux increases accompanying with the increasing of operation pressure; (4) the paper filtered COD concentration has more affection on the water flux than the suspended solid concentration; (5) as the volume loading of MBR increases, the accumulation of high molecule organic substance and colloid increases, the membrane permeate COD concentration and paper filtered COD concentration increase too, meanwhile the water flux reduces; (6) when the sludge retention time of activated sludge of MBR increases, the accumulation of high molecule organic substance and colloid reduces, the membrane permeate COD concentration and paper filtered COD concentration reduce too, and the water flux increases; (7) comparing with the conventional biological process, the microbial activity is higher, but the microbial species is less.

  20. Anaerobic digestion of waste biomass from the production of L-cystine in suspended-growth bioreactors.

    PubMed

    Chávez-Fuentes, Juan José; Hutňan, Miroslav; Bodík, Igor; Zakhar, Ronald; Czölderová, Marianna

    2015-01-01

    Waste biomass from the industrial production of the amino acid L-cystine contains above-average concentrations of organic pollutants and significant concentrations of nitrogen and sulfur. The specific biogas production (SBP) of waste biomass was monitored in parallel suspended-growth laboratory anaerobic bioreactors. After severe inhibition was observed, three different procedures were applied to inhibited reactor sludge to counter-attack the inhibitory effects of sulfides, respectively hydrogen sulfide: micro-aeration, dilution with water and precipitation by ferrous iron cations. The performance of bioreactors was weekly monitored. Organic loading rates (as chemical oxygen demand, COD) ranged from 1.07 to 1.97 g L(-1) d(-1). At the end of the experimentation, SBP averaged 217, 300 and 320 l kg(-1) COD with a methane content of 21%, 52% and 54%; specific sludge production averaged 133, 111 and 400 g total solids kg(-1) COD, and inhibition was 49%, 27% and 25%; for the applied procedures of micro-aeration, dilution and precipitation respectively.

  1. Enhanced submerged membrane bioreactor combined with biosurfactant rhamnolipids: performance for frying oil degradation and membrane fouling reduction.

    PubMed

    Qin, Lei; Zhang, Guoliang; Meng, Qin; Zhang, Hongzi; Xu, Lusheng; Lv, Bosheng

    2012-12-01

    In this study, a novel submerged membrane bioreactor (SMBR) combined with rhamnolipids was developed to treat frying oil wastewater and control the problem of membrane fouling. To validate the feasibility of this new design, a hybrid SMBR with additional rhamnolipids (RSMBR) and a controlled SMBR (CSMBR) were run in parallel. Results demonstrated that RSMBR not only held high removal efficiency of oil up to 90% at short hydraulic time, but also exhibited 10 times higher membrane permeability in comparison to CSMBR. The presence of rhamnolipids greatly enhanced the contact and reaction between the microorganism and oil molecules. The great improvement in membrane filterability was associated with an increase in hydrophobicity of flocs as well as the increase of particle size from 53.06 to 145.54 μm. The oil strongly adhered to the surface of flocs by rhamnolipids, and consequently prevented larger oil droplets directly depositing on the membrane surface.

  2. Effect of solid retention time on membrane fouling in membrane bioreactor: from the perspective of quorum sensing and quorum quenching.

    PubMed

    Yu, Huarong; Xu, Guoren; Qu, Fangshu; Li, Guibai; Liang, Heng

    2016-09-01

    Solid retention time (SRT) is one of the most important operational parameters in membrane bioreactor (MBR), which significantly influences membrane fouling. It is widely recognized that SRT mainly changes biomass characteristics, and then, influences membrane fouling. Effect of SRT on quorum sensing (QS) in MBR, which could also influence fouling by coordinating biofilm formation, has not been reported. In this study, fouling, QS, soluble microbial products (SMP), and extracellular polymer substances (EPS) in MBRs operated under SRTs of 4, 10, and 40 days were investigated. The results showed that as SRT increased, the abundance of quorum quenching (QQ) bacteria increased, the quorum signal degradation activity of activated sludge increased, the concentrations of signal molecules in MBR decreased, the excretion of SMP and EPS decreased, and thus membrane biofouling was alleviated. Therefore, besides altering the biomass physiochemical properties, SRT also changed the balance between QS and QQ in MBR, and in this way, influenced membrane biofouling.

  3. Analysis of the microbial community structure in a membrane bioreactor during initial stages of filtration.

    PubMed

    Piasecka, Anna; Souffreau, Caroline; Vandepitte, Katrien; Vanysacker, Louise; Bilad, Roil M; Bie, Tom De; Hellemans, Bart; Meester, Luc De; Yan, Xinxin; Declerck, Priscilla; Vankelecom, Ivo F J

    2012-01-01

    Membrane biofouling was investigated during the early stages of filtration in a laboratory-scale membrane bioreactor operated on molasses wastewater. The bacterial diversity and composition of the membrane biofilm and activated sludge were analyzed using terminal restriction fragment length polymorphism coupled with 16S rRNA clone library construction and sequencing. The amount of extracellular polymeric substances produced by bacteria was investigated using spectroscopic methods. The results reveal that the bacterial community of activated sludge differs significantly from that of the membrane biofilm, especially at the initial phase. Phylogenetic analysis based on 16S rRNA gene sequences identified 25 pioneer OTUs responsible for membrane surface colonization. Also, the relationship between the identified bacterial strains and the system specifications was explored.

  4. Nitrogen removal pathway of anaerobic ammonium oxidation in on-site aged refuse bioreactor.

    PubMed

    Wang, Chao; Zhao, Youcai; Xie, Bing; Peng, Qing; Hassan, Muhammad; Wang, Xiaoyuan

    2014-05-01

    The nitrogen removal pathways and nitrogen-related functional genes in on-site three-stage aged refuse bioreactor (ARB) treating landfill leachate were investigated. It was found that on average 90.0% of CODCr, 97.6% of BOD5, 99.3% of NH4(+)-N, and 81.0% of TN were removed with initial CODCr, BOD5, NH4(+)-N, and TN concentrations ranging from 2323 to 2754, 277 to 362, 1237 to 1506, and 1251 to 1580 mg/L, respectively. Meanwhile, the functional genes amoA, nirS and anammox 16S rRNA gene were found to coexist in every bioreactor, and their relative proportions in each bioreactor were closely related to the pollutant removal performance of the corresponding bioreactor, which indicated the coexistence of multiple nitrogen removal pathways in the ARB. Detection of anammox expression proved the presence of the anammox nitrogen removal pathway during the process of recirculating mature leachate to the on-site ARB, which provides important information for nitrogen management in landfills.

  5. Enrichment and characterization of microbial consortia degrading soluble microbial products discharged from anaerobic methanogenic bioreactors.

    PubMed

    Kim, Na-Kyung; Oh, Seungdae; Liu, Wen-Tso

    2016-03-01

    Soluble microbial products (SMP) produced in bioprocesses have been known as a main cause to decrease treatment efficiency, lower effluent quality, and promote membrane fouling in water reclamation plants. In this study, biological degradation of SMP using selectively enriched microbial consortia in a down-flow hanging sponge (DHS) reactor was introduced to remove SMP discharged from anaerobic methanogenic reactors. On average, 68.9-87.5% SMP removal was achieved by the enriched microbial consortia in the DHS reactor for >800 days. The influent SMP fed to the DHS reactor exhibited a bimodal molecular weight (MW) distribution with 14-20 kDa and <4 kDa. Between these two types of SMP, the small MW SMP were biodegraded in the upper part of the reactor, together with most of the large MW SMP. Using 16S rRNA gene pyrosequencing technology, the microbial community composition and structure were characterized and correlated with operational factors, such as hydraulic retention time, organic loading rate, and removal of soluble chemical oxygen demand at different depths of the reactor, by performing network and redundancy analyses. The results revealed that Saprospiraceae was strongly correlated to the increasing SMP loading condition, indicating positive co-occurrences with neighboring bacterial populations. Different microbial diversity along with the depth of the reactor implies that stratified microbial communities could participate in the process of SMP degradation. Taken together, these observations indicate that the spatial and temporal variability of the enriched microbial community in the DHS reactor could effectively treat SMP with respect to changes in the operational factors.

  6. Removals of pharmaceutical compounds from hospital wastewater in membrane bioreactor operated under short hydraulic retention time.

    PubMed

    Prasertkulsak, S; Chiemchaisri, C; Chiemchaisri, W; Itonaga, T; Yamamoto, K

    2016-05-01

    Pilot-scale membrane bioreactor (MBR) was operated at a short hydraulic retention time (HRT) of 3 h for the treatment of hospital wastewater. The removals of eleven pharmaceutical compounds in MBR operated at different mixed liquor suspended solids (MLSS) level were investigated during which nitrification degree was differed. The results experiments revealed the importance of immediate adsorption onto the colloidal particles in supernatant of MBR sludge and subsequently removed by membrane filtration for the recalcitrant pharmaceutical compounds. Nevertheless, the removals through biodegradation during short HRT were also found significant for some compounds. DGGE profile revealed the development of pharmaceutical degrading microorganisms in MBR.

  7. Specific energy consumption of membrane bioreactor (MBR) for sewage treatment.

    PubMed

    Krzeminski, Pawel; van der Graaf, Jaap H J M; van Lier, Jules B

    2012-01-01

    This paper provides an overview of current electric energy consumption of full-scale municipal MBR installations based on literature review and case studies. Energy requirements of several MBRs were linked to operational parameters and reactor performance. Total and specific energy consumption data were analysed on a long-term basis with special attention given to treated flow, design capacity, membrane area and effluent quality. The specific energy consumption of an MBR system is dependent on many factors, such as system design and layout, volume of treated flow, membrane utilization and operational strategy. Operation at optimal flow conditions results in a low specific energy consumption and energy efficient process. Energy consumption of membrane related modules was in the range of 0.5-0.7 kWh/m(3) and specific energy consumption for membrane aeration in flat sheet (FS) was 33-37% higher than in a hollow fibre (HF) system. Aeration is a major energy consumer, often exceeding 50% share of total energy consumption. In consequence, coarse bubble aeration applied for continuous membrane cleaning remains the main target for energy saving actions. Also, a certain potential for energy optimization without immediate danger of affecting the quality of the produced effluent was observed.

  8. Salt stress in a membrane bioreactor: dynamics of sludge properties, membrane fouling and remediation through powdered activated carbon dosing.

    PubMed

    De Temmerman, L; Maere, T; Temmink, H; Zwijnenburg, A; Nopens, I

    2014-10-15

    Membrane bioreactors are a well-established technology for wastewater treatment. However, their efficiency is adversely impacted by membrane fouling, primarily inciting very conservative operations of installations that makes them less appealing from an economic perspective. This fouling propensity of the activated sludge is closely related to system disturbances. Therefore, improved insight into the impact of fouling is crucial towards increased membrane performance. In this work, the disturbance of a salt shock was investigated with respect to sludge composition and filterability in two parallel lab-scale membrane bioreactors. Several key sludge parameters (soluble microbial products, sludge-bound extracellular polymeric substances, supramicron particle size distributions (PSD), submicron particle concentrations) were intensively monitored prior to, during, and after a disturbance to investigate its impact as well as the potential governing mechanism. Upon salt addition, the supramicron PSD immediately shifted to smaller floc sizes, and the total fouling rate increased. Following a certain delay, an increase in submicron particles, supernatant proteins, and polysaccharides was observed as well as an increase in the irreversible membrane fouling rate. Recovery from the disturbance was evidenced with a simultaneous decrease in the above mentioned quantities. A similar experiment introducing powdered activated carbon (PAC) addition used for remediation resulted in either no or less significant changes in the above mentioned quantities, signifying its potential as a mitigation strategy.

  9. Assessment of a novel overflow-type electrochemical membrane bioreactor (EMBR) for wastewater treatment, energy recovery and membrane fouling mitigation.

    PubMed

    Zhou, Guowang; Zhou, Yuhong; Zhou, Guoqiang; Lu, Lian; Wan, Xiankai; Shi, Huixiang

    2015-11-01

    A novel overflow-type electrochemical membrane bioreactor (EMBR) without ion exchange membrane, was developed for wastewater treatment and utilized electricity recovered by microbial fuel cell (MFC) for membrane fouling mitigation in membrane bioreactor (MBR). The maximum power density of 629mW/m(3) or 7.18mW/m(2) was obtained. The removal efficiencies of chemical oxygen demand, ammonia nitrogen and total nitrogen under appropriate ranges of hydraulic retention times (16.9-8.5h) were 92.6±5.4%, 96.5±2.8% and 73.9±9.7%, respectively. Sequencing showed electrochemically active bacteria Lactococcus, Bacillus and Saprospiraceae_uncultured were abundant in the biofilm. Compared with a conventional MBR, five significant effects of the MFC integration on the sludge properties, including particle zeta potential decrease, particle size distribution macroaggregation, soluble microbial products and extracellular polymeric substances reduction and SMPP/SMPC ratio increase, were achieved in this system, leading to membrane fouling mitigation. This system shows great promise for practical wastewater treatment application.

  10. Pilot study of a submerged membrane bioreactor for water reclamation.

    PubMed

    Qin, Jian-Jun; Oo, Maung Htun; Tao, Guihe; Kekre, Kiran A; Hashimoto, Tomotaka

    2009-01-01

    The objective of this pilot study was to investigate the operational conditions of newly developed MBR modules for water reclamation under tropical conditions. MUDC-620A MBR modules with hollow fibre PVDF membranes from Asahi-Kasei Chemicals were used in the study. The pilot plant with capacity of 50 m(3)/d was operated continuously (24-hour) over four months on site of Ulu Pandan Water Reclamation Plant (UPWRP) in Singapore. During the study, the MLSS in membrane tank was in the range of 6,840 approximately 9,540 mg/L. Filtration operation mode of the membrane unit was 9 minutes on production and 1 minute backwash. The air scouring for the membranes was 0.18-0.30 Nm(3)/h per m(2) membrane area all of the time. Trials on different membrane fluxes were conducted to obtain the sustainable flux. The analytical results showed that COD, TOC, T-N and NH4-N of the treated water were <30 mg/L, 5-7 mg/L, <13 mg/L and <0.1 mg/L, respectively, which met the requirement of Industrial Water for reuse. TMP was in the range of 12-40 kPa and could be recovered after cleaning with 2,000 mg/L sodium hypochlorite solution. Sludge clogging could be a challenge for long-term operation with the current module design. It was concluded that it was feasible for MUDC-620A MBR to operate at a net flux of 25-29 LMH (or 0.6-0.7 m/d) for treating the municipal wastewater at UPWRP.

  11. Algae Bioreactor Using Submerged Enclosures with Semi-Permeable Membranes

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan D (Inventor); Gormly, Sherwin J (Inventor); Embaye, Tsegereda N (Inventor); Delzeit, Lance D (Inventor); Flynn, Michael T (Inventor); Liggett, Travis A (Inventor); Buckwalter, Patrick W (Inventor); Baertsch, Robert (Inventor)

    2013-01-01

    Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO.sub.2/O.sub.2 exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a "dead zone") containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

  12. SANASA Capivari II - the first full-scale municipal membrane bioreactor in Latin America.

    PubMed

    Pagotto, R; Rossetto, R; Gasperi, R L P; Andrade, J P; Trovati, J; Vallero, M V G; Okumura, A; Arntsen, B

    2014-01-01

    The macro region of Campinas (Brazil) is rapidly evolving with new housing developments and industries, creating the challenge of finding new ways to treat wastewater to a quality that can be reused in order to overcome water scarcity problems. To address this challenge, SANASA (a publicly owned water and wastewater concessionaire from Campinas) has recently constructed the 'EPAR (Water Reuse Production Plant) Capivari II' using the GE ZeeWeed 500D(®) ultrafiltration membrane system. This is the first large-scale membrane bioreactor (MBR) system in Latin America with biological tertiary treatment capability (nitrogen and phosphorus removal), being able to treat an average flow of 182 L/s in its first phase of construction. The filtration system is composed of three membrane trains with more than 36,000 m(2) of total membrane filtration area. The membrane bioreactor (MBR) plant was commissioned in April 2012 and the permeate quality has exceeded expectations. Chemical oxygen demand (COD) removal rates are around and above 97% on a consistent basis, with biochemical oxygen demand (BOD5) and NH3 (ammonia) concentrations at very low levels, and turbidity lower than 0.3 nephelometric turbidity unit (NTU). Treated effluent is sent to a water reuse accumulation tank (from where will be distributed as reuse water), and the excess is discharged into the Capivari River.

  13. Ion exchange membrane textile bioreactor as a new alternative for drinking water denitrification.

    PubMed

    Berdous, Dalila; Akretche, Djamal-Eddine; Abderahmani, Ahmed; Berdous, Sakina; Meknaci, Rima

    2014-06-01

    This work enters in the optics of the denitrification of a polluted water by two membrane techniques, the Donnan dialysis (DD) and the ion exchange membrane bioreactor (IEMB), using a conventional barrier, composed by an anion exchange membrane (AEM), and a hybrid barrier, where the AEM is combined to an anion exchange textile (AET). The effects of the hydrodynamic factor and the nature of the carbon source on the transfer and the reduction of nitrate ions were studied. The study results obtained through the DD showed the effectiveness of the hybrid barrier in the recovery and concentration of nitrate ions. This was also recorded during denitrification by the hybrid process, called the ion exchange membrane textile bioreactor (IEMTB), with a significant reduction of nitrates, compared to IEMB, due to the efficiency of the Pseudomonas aeruginosa biofilm formed at the surface of the AET. Here, the permselectivity of the membrane and the good bioreduction of the pollutants are no longer major conditions to the better performance of the process. The application of IEMTB in the denitrification of groundwater, having a nitrate concentration of 96.67 ppm, shows a total reduction of nitrate ions without changing the quality of the water. Indeed, the analysis of the recovered water, or yet the treated water, shows the absence of the bacterium by-products and concentrations in the nitrates and nitrites which are, respectively, equal to 0.02±0.01 ppm, and inferiors to the detection limit (<0.02 ppm).

  14. Application of a low cost ceramic filter to a membrane bioreactor for greywater treatment.

    PubMed

    Hasan, Md Mahmudul; Shafiquzzaman, Md; Nakajima, Jun; Ahmed, Abdel Kader T; Azam, Mohammad Shafiul

    2015-03-01

    The performance of a low cost and simple ceramic filter to a membrane bioreactor (MBR) process was evaluated for greywater treatment. The ceramic filter was submerged in an acrylic cylindrical column bioreactor. Synthetic greywater (prepared by shampoo, dish cleaner and laundry detergent) was fed continuously into the reactor. The filter effluent was obtained by gravitational pressure. The average flux performance was observed to be 11.5 LMH with an average hydraulic retention time of 1.7 days. Complete biodegradation of surfactant (methylene blue active substance removal: 99-100%) as well as high organic removal performance (biochemical oxygen demand: 97-100% and total organic carbon: >88%) was obtained. The consistency of flux (11.5 LMH) indicated that the filter can be operated for a long time without fouling. The application of this simple ceramic filter would make MBR technology cost-effective in developing countries for greywater reclamation and reuse.

  15. Effects of salinity build-up on the performance and bacterial community structure of a membrane bioreactor.

    PubMed

    Luo, Wenhai; Phan, Hop V; Hai, Faisal I; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2016-01-01

    This study investigated the effects of salinity increase on bacterial community structure in a membrane bioreactor (MBR) for wastewater treatment. The influent salt loading was increased gradually to simulate salinity build-up in the bioreactor during the operation of a high retention-membrane bioreactor (HR-MBR). Bacterial community diversity and structure were analyzed using 454 pyrosequencing of 16S rRNA genes of MBR mixed liquor samples. Results show that salinity increase reduced biological performance but did not affect microbial diversity in the bioreactor. Unweighted UniFrac and taxonomic analyses were conducted to relate the reduced biological performance to the change of bacterial community structure. In response to the elevated salinity condition, the succession of halophobic bacteria by halotolerant/halophilic microbes occurred and thereby the biological performance of MBR was recovered. These results suggest that salinity build-up during HR-MBR operation could be managed by allowing for the proliferation of halotolerant/halophilic bacteria.

  16. Microbial fuel cells and osmotic membrane bioreactors have mutual benefits for wastewater treatment and energy production.

    PubMed

    Hou, Dianxun; Lu, Lu; Ren, Zhiyong Jason

    2016-07-01

    This study demonstrates that microbial fuel cells (MFCs) and osmotic membrane bioreactors (OMBRs) can be mutually beneficial when integrated together for wastewater treatment. When connecting MFCs with OMBRs, the solute buildup increased conductivity and buffer capacity, which greatly increased MFC power density from 3 W/m(3) up to 11.5 W/m(3). In turn, the MFCs conditioned and reduced sludge production and therefore reduced forward osmosis (FO) membrane fouling. The MFC-OMBR equipped with new thin-film composite (TFC) membrane showed excellent organic (>95%) and phosphorus removal (>99%) and therefore maintained effluent sCOD below 20 mg/L. However, the nitrogen removal was limited due to the negative surface charge of the thin-film composite membrane and solution chemistry, which led to higher flux of ammonium toward the OMBR draw solution. Further studies are needed to improve nitrogen removal, reduce fouling, and optimize system integration.

  17. A modeling study of fouling development in membrane bioreactors for wastewater treatment.

    PubMed

    Liang, Shuang; Song, Lianfa; Tao, Guihe; Kekre, Kiran Arun; Seah, Harry

    2006-08-01

    Membrane fouling is a primary concern in membrane bioreactors (MBRs) in wastewater treatment because it strongly affects both system stability and economic feasibility. A mathematical model was developed in this study for membrane fouling in submerged MBR systems for wastewater treatment, in which both reversible and irreversible fouling were quantified. While mixed liquor suspended solids are the major components of the reversible fouling layer, dissolved organic matter is thought to be the key foulant, in particular, responsible for the long-term irreversible fouling of the filtration unit. The model was calibrated (parameter identification) with a set of operational data from a pilot MBR and then verified with other independent operational data from the MBR. The good agreement between theoretical predictions and operational data demonstrates that the outlined modeling concept can be successfully applied to describe membrane fouling in submerged MBR systems.

  18. Mercury removal from water streams through the ion exchange membrane bioreactor concept.

    PubMed

    Oehmen, Adrian; Vergel, Dario; Fradinho, Joana; Reis, Maria A M; Crespo, João G; Velizarov, Svetlozar

    2014-01-15

    Mercury is a highly toxic heavy metal that causes human health problems and environmental contamination. In this study, an ion exchange membrane bioreactor (IEMB) process was developed to achieve Hg(II) removal from drinking water and industrial effluents. Hg(II) transport through a cation exchange membrane was coupled with its bioreduction to Hg(0) in order to achieve Hg removal from concentrated streams, with minimal production of contaminated by-products observed. This study involves (1) membrane selection, (2) demonstration of process effectiveness for removing Hg from drinking water to below the 1ppb recommended limit, and (3) process application for treatment of concentrated water streams, where >98% of the Hg was removed, and the throughput of contaminated water was optimised through membrane pre-treatment. The IEMB process represents a novel mercury treatment technology with minimal generation of contaminated waste, thereby reducing the overall environmental impact of the process.

  19. Package plant of extended aeration membrane bioreactors: a study on aeration intensity and biofouling control.

    PubMed

    Ujang, Z; Ng, S S; Nagaoka, H

    2005-01-01

    Biofouling control is important for effective process of membrane bioreactor (MBR). In this study, phenomena of biofouling for immersed type extended aeration MBR with two different anti-fouling aeration intensities were studied through a laboratory set up. The objectives of this study were (a) to observe biofouling phenomena of MBR that operates under different anti-fouling bubbling intensity, and simultaneously monitors performance of the MBR in organic carbon and nutrients removal; (b) to compare effectiveness of detergent and detergent-enzyme cleaning solutions in recovering biofouled membranes that operated in the extended aeration MBR. For MBR, which operated under continuous anti-fouling aeration, deposition and accumulation of suspended biomass on membrane surface were prohibited. However, flux loss was inescapable that biofilm layer was the main problem. Membrane cleaning was successfully carried out with detergent-enzyme mixture solutions and its effectiveness was compared with result from cleaning with just detergent solution.

  20. High strength domestic wastewater treatment with submerged forward osmosis membrane bioreactor.

    PubMed

    Aftab, Bilal; Khan, Sher Jamal; Maqbool, Tahir; Hankins, Nicholas P

    2015-01-01

    Forward osmosis membranes are less prone to fouling with high rejection of salts, and the osmotic membrane bioreactor (OMBR) can be considered as an innovative membrane technology for wastewater treatment. In this study, a submerged OMBR having a cellulose triacetate membrane, with the active layer facing the feed solution configuration, was operated at different organic loading rates (OLRs), i.e., 0.4, 1.2 and 2.0 kg-COD/(m(3)·d) with chemical oxygen demand (COD) concentrations of 200 mg/L, 600 mg/L and 1,000 mg/L, respectively, to evaluate the performance on varying wastewater strengths. High organic content with sufficient amount of nutrients enhanced the biomass growth. High OLR caused more extrapolymeric substances production and less dewaterability. However, no significant differences in fouling trends and flux rates were observed among different OLR operational conditions.

  1. Effect of a microbiota activator on accumulated ammonium and microbial community structure in a pilot-scale membrane bioreactor.

    PubMed

    Sato, Yuya; Hori, Tomoyuki; Navarro, Ronald R; Ronald, Navarro R; Habe, Hiroshi; Ogata, Atsushi

    2015-01-01

    Microbiota activators (MAs) have been used to improve the reactor performances of biological wastewater treatment processes. In this study, to remove ammonium (NH4(+)) accumulated during the pre-operation of a pilot-scale membrane bioreactor (MBR) under high-organic-loading conditions, an MA was added to the MBR system and the resulting changes in reactor performances and microbial communities were monitored for 12 days. The NH4(+) concentrations in the sludge and effluent decreased (from 427 to 246 mg/L in the sludge (days 1-9)), and mixed liquor suspended solid increased (from 6,793 to 11,283 mg/L (days 1-12)) after the addition of MA. High-throughput Illumina sequencing of 16S rRNA genes revealed that the microbial community structure changed along with the NH4(+) removal resulting from the MA addition. In particular, the relative abundance of an Acidovorax-related operational taxonomic unit (OTU) increased significantly, accounting for approximately 50% of the total microbial population at day 11. In contrast, the ammonia-oxidizing bacteria and archaea showed low abundances (<0.05%), and no anaerobic ammonia oxidizers were detected. These results suggested that the Acidovorax-related OTU was mainly involved in the NH4(+) removal in the MBR, probably due to its ammonia-assimilating metabolism.

  2. Outcomes of a 2-year investigation on enhanced biological nutrients removal and trace organics elimination in membrane bioreactor (MBR).

    PubMed

    Lesjean, B; Gnirss, R; Buisson, H; Keller, S; Tazi-Pain, A; Luck, F

    2005-01-01

    Two configurations of membrane bioreactors were identified to achieve enhanced biological phosphorus and nitrogen removal, and assessed over more than two years with two parallel pilot plants of 2m3 each. Both configurations included an anaerobic zone ahead of the biological reactor, and differed by the position of the anoxic zone: standard pre-denitrification, or post-denitrification without dosing of carbon source. Both configurations achieved improved phosphorus removal. The goal of 50 microgP/L in the effluent could be consistently achieved with two types of municipal wastewater, the second site requiring a low dose of ferric salt ferric salt < 3 mgFe/L. The full potential of biological phosphorus removal could be demonstrated during phosphate spiking trials, where up to 1 mg of phosphorus was biologically eliminated for 10 mg BOD5 in the influent. The post-denitrification configuration enabled a very good elimination of nitrogen. Daily nitrate concentration as low as 1 mgN/L could be monitored in the effluent in some periods. The denitrification rates, greater than those expected for endogenous denitrification, could be accounted for by the use of the glycogene pool, internally stored by the denitrifying microorganisms in the anaerobic zone. Pharmaceuticals residues and steroids were regularly monitored on the two parallel MBR pilot plants during the length of the trials, and compared with the performance of the Berlin-Ruhleben WWTP. Although some compounds such as carbamazepine were persistent through all the systems, most of the compounds could be better removed by the MBR plants. The influence of temperature, sludge age and compound concentration could be shown, as well as the significance of biological mechanisms in the removal of trace organic compounds.

  3. The application of membrane biological reactors for the treatment of wastewaters

    SciTech Connect

    Brindle, K.; Stephenson, T.

    1996-03-20

    Combining membrane technology with biological reactors for the treatment of municipal and industrial wastewaters has led to the development of three generic membrane processes within bioreactors: for separation and recycle of solids; for bubbleless aeration of the bioreactor; and for extraction of priority organic pollutants from hostile industrial wastewaters. Commercial aerobic and anaerobic membrane separation bioreactors already provides a small footprint alternative to conventional biological treatment methods, producing a high-quality effluent at high organic loading rates. Both the bubbleless aeration and extractive membrane bioreactors are in the development stages. The former uses gas-permeable membranes to improve the mass transfer of oxygen to the bioreactor by providing bubbleless oxygen. By using a silicon membrane process, extractive membrane bioreactors transfer organic pollutants from chemically hostile wastewaters to a nutrient medium for subsequent biodegradation. All three membrane bioreactor (MBR) processes are comparatively and critically reviewed.

  4. An atomic force microscopy study on fouling characteristics of modified PES membrane in submerged membrane bioreactor for domestic wastewater treatment

    NASA Astrophysics Data System (ADS)

    Liu, Shuo; Han, Hongjun; Liu, Yanping; Wang, Baozhen

    2008-10-01

    To investigate the fouling characteristics of modified PES membrane in submerged Membrane Bioreactor (MBR) for domestic wastewater treatment, Atomic Force Microscope (AFM) study was conducted to analyze the microstructure characteristics of PES membrane. Surface roughness and section analysis of both virgin and fouled membrane were achieved by software of NanoScope 6.12. Compared to the virgin membrane, the average roughness (Ra), square average roughness (Rms) and ten points average roughness (Rz) of fouled membrane were increased by 100.6nm, 133.7nm and 330.7nm respectively. The section analysis results indicated that the cake layer formed and membrane pore blocked were the main causes for the increase of TMP. Micro-filtration resistance analysis was conducted to support the results of AFM analysis. It is showed that membrane resistance, cake resistance, pore blocking and irreversible fouling resistance is 0.755, 1.721 and 1.386 respectively, which contributed 20%, 44%, and 36%, respectively, to total resistance of submerged MBR (at MLSS 6000mg/L and flux 21.9L/m2Â.h). The results proved that AFM could be used to properly describe the fouling characteristics of modified PES membrane in submerged MBR through roughness and section analysis.

  5. Simultaneous removal of C, N, P from cheese whey by jet loop membrane bioreactor (JLMBR).

    PubMed

    Farizoglu, Burhanettin; Keskinler, Bulent; Yildiz, Ergun; Nuhoglu, Alper

    2007-07-19

    The membrane bioreactor (MBR) used in this study consisted of a jet loop bioreactor (aerobic high rate system) and a membrane separation unit (microfiltration). Jet loop membrane bioreactor (JLMBR) system is a high performance treatment system. High organic loading rates can be achieved with a very small footprint. The JLMBR is a compact biological treatment system which requires much smaller tank volumes than conventional activated sludge system. Solid-liquid separation is performed with a membrane. The JLMBR system, of 35 L capacity, was operated continuously for 3 months with a sludge age of 1.1-2.8 days and chemical oxygen demand (COD) loads of 3.5-33.5 kg COD m(-3) day(-1). The mean concentration values of COD, total nitrogen (TN) and PO(4)3- in cheese whey (CW) were found as 78,680 mg L(-1), 1125 mg L(-1) and 378 mg L(-1), respectively. Ninety-seven percent COD removal rate was obtained at the sludge age (Thetac) of 1.6 days and volumetric loads of 22.2 kg COD m(-3) day(-1). TN removal was obtained as 99% at the loading rates of 17-436 g TN m(-3) day(-1). PO4(3-) removals were between 65 and 88% for the loading of 30-134 gPO4(3-) m(-3) day(-1). The system could simultaneously remove the COD, TN and PO(4)3- at high efficiencies. The sludge flocks were highly motile, dispersed and had poor settling properties.

  6. Microbial production of homogeneously layered cellulose pellicles in a membrane bioreactor.

    PubMed

    Hofinger, M; Bertholdt, G; Weuster-Botz, D

    2011-09-01

    Microbial cellulose (MC) is being investigated for various applications in the field of biomedical engineering. Gluconacetobacter xylinus is able to produce pure cellulose in the form of a hydrogel ("pellicle"). The pellicle consists of a defined tridimensional structure that is sensitive to mechanical stress during the process of formation. The bacteria, however, are obligate aerobic and need to be supplied with oxygen. These two objectives are often conflicting. A lab-scale membrane bioreactor prototype was developed which is able to efficiently produce a MC pellicle with a homogeneous layered structure. A hydrophilic microfiltration polyethersulfone membrane separates the bacteria from the cultivation medium. This setup allows the free convective exchange of the cultivation medium, while providing mechanical support for the continuous formation of the MC layer. Thickness of the MC layer was measured online by a laser triangulation sensor. One hundred and twenty five gram cellulose dry weight/m(2) membrane surface were produced within a process time of 330 h. Membrane bioreactors may be used to produce homogenous MC layers in a variety of shapes suitable for biomedical applications.

  7. Anaerobic-aerobic sequencing bioreactors improve energy efficiency for treatment of personal care product industry wastes.

    PubMed

    Ahammad, S Z; Bereslawski, J L; Dolfing, J; Mota, C; Graham, D W

    2013-07-01

    Personal care product (PCP) industry liquid wastes contain shampoo residues, which are usually treated by aerobic activated sludge (AS). Unfortunately, AS is expensive for PCP wastes because of high aeration and energy demands, whereas potentially energy-positive anaerobic designs cannot meet effluent targets. Therefore, combined anaerobic-aerobic systems may be the best solution. Seven treatment systems were assessed in terms of energy and treatment performance for shampoo wastes, including one aerobic, three anaerobic (HUASB, AHR and AnCSTR) and three anaerobic-aerobic reactor designs. COD removals were highest in the HUASB-aerobic (87.9 ± 0.4%) and AHR-aerobic (86.8±0.5%) systems, which used 69.2% and 62.5% less energy than aerobic AS. However, actual methane production rates were low relative to theoretical in the UASB and AHR units (∼10% methane/COD removed) compared with the AnCSTR unit (∼70%). Anaerobic-aerobic sequence reactors show promise for treating shampoo wastes, but optimal designs depend upon whether methane production or COD removal is most important to operations.

  8. Temporal changes in extracellular polymeric substances on hydrophobic and hydrophilic membrane surfaces in a submerged membrane bioreactor.

    PubMed

    Matar, Gerald; Gonzalez-Gil, Graciela; Maab, Husnul; Nunes, Suzana; Le-Clech, Pierre; Vrouwenvelder, Johannes; Saikaly, Pascal E

    2016-05-15

    Membrane surface hydrophilic modification has always been considered to mitigating biofouling in membrane bioreactors (MBRs). Four hollow-fiber ultrafiltration membranes (pore sizes ∼0.1 μm) differing only in hydrophobic or hydrophilic surface characteristics were operated at a permeate flux of 10 L/m(2) h in the same lab-scale MBR fed with synthetic wastewater. In addition, identical membrane modules without permeate production (0 L/m(2) h) were operated in the same lab-scale MBR. Membrane modules were autopsied after 1, 10, 20 and 30 days of MBR operation, and total extracellular polymeric substances (EPS) accumulated on the membranes were extracted and characterized in detail using several analytical tools, including conventional colorimetric tests (Lowry and Dubois), liquid chromatography with organic carbon detection (LC-OCD), fluorescence excitation - emission matrices (FEEM), fourier transform infrared (FTIR) and confocal laser scanning microscope (CLSM). The transmembrane pressure (TMP) quickly stabilized with higher values for the hydrophobic membranes than hydrophilic ones. The sulfonated polysulfone (SPSU) membrane had the highest negatively charged membrane surface, accumulated the least amount of foulants and displayed the lowest TMP. The same type of organic foulants developed with time on the four membranes and the composition of biopolymers shifted from protein dominance at early stages of filtration (day 1) towards polysaccharides dominance during later stages of MBR filtration. Nonmetric multidimensional scaling of LC-OCD data showed that biofilm samples clustered according to the sampling event (time) regardless of the membrane surface chemistry (hydrophobic or hydrophilic) or operating mode (with or without permeate flux). These results suggest that EPS composition may not be the dominant parameter for evaluating membrane performance and possibly other parameters such as biofilm thickness, porosity, compactness and structure should be

  9. A novel composite conductive microfiltration membrane and its anti-fouling performance with an external electric field in membrane bioreactors

    NASA Astrophysics Data System (ADS)

    Huang, Jian; Wang, Zhiwei; Zhang, Junyao; Zhang, Xingran; Ma, Jinxing; Wu, Zhichao

    2015-03-01

    Membrane fouling remains an obstacle to wide-spread applications of membrane bioreactors (MBRs) for wastewater treatment and reclamation. Herein, we report a simple method to prepare a composite conductive microfiltration (MF) membrane by introducing a stainless steel mesh into a polymeric MF membrane and to effectively control its fouling by applying an external electric field. Linear sweep voltammetry and electrochemical impedance spectroscopy analyses showed that this conductive membrane had very good electrochemical properties. Batch tests demonstrated its anti-fouling ability in filtration of bovine serum albumin, sodium alginate, humic acid and silicon dioxide particles as model foulants. The fouling rate in continuous-flow MBRs treating wastewater was also decreased by about 50% for this conductive membrane with 2 V/cm electric field compared to the control test during long-term operation. The enhanced electrostatic repulsive force between foulants and membrane, in-situ cleaning by H2O2 generated from oxygen reduction, and decreased production of soluble microbial products and extracellular polymeric substances contributed to fouling mitigation in this MBR. The results of this study shed light on the control strategy of membrane fouling for achieving a sustainable operation of MBRs.

  10. A novel composite conductive microfiltration membrane and its anti-fouling performance with an external electric field in membrane bioreactors

    PubMed Central

    Huang, Jian; Wang, Zhiwei; Zhang, Junyao; Zhang, Xingran; Ma, Jinxing; Wu, Zhichao

    2015-01-01

    Membrane fouling remains an obstacle to wide-spread applications of membrane bioreactors (MBRs) for wastewater treatment and reclamation. Herein, we report a simple method to prepare a composite conductive microfiltration (MF) membrane by introducing a stainless steel mesh into a polymeric MF membrane and to effectively control its fouling by applying an external electric field. Linear sweep voltammetry and electrochemical impedance spectroscopy analyses showed that this conductive membrane had very good electrochemical properties. Batch tests demonstrated its anti-fouling ability in filtration of bovine serum albumin, sodium alginate, humic acid and silicon dioxide particles as model foulants. The fouling rate in continuous-flow MBRs treating wastewater was also decreased by about 50% for this conductive membrane with 2 V/cm electric field compared to the control test during long-term operation. The enhanced electrostatic repulsive force between foulants and membrane, in-situ cleaning by H2O2 generated from oxygen reduction, and decreased production of soluble microbial products and extracellular polymeric substances contributed to fouling mitigation in this MBR. The results of this study shed light on the control strategy of membrane fouling for achieving a sustainable operation of MBRs. PMID:25784160

  11. A novel composite conductive microfiltration membrane and its anti-fouling performance with an external electric field in membrane bioreactors.

    PubMed

    Huang, Jian; Wang, Zhiwei; Zhang, Junyao; Zhang, Xingran; Ma, Jinxing; Wu, Zhichao

    2015-03-18

    Membrane fouling remains an obstacle to wide-spread applications of membrane bioreactors (MBRs) for wastewater treatment and reclamation. Herein, we report a simple method to prepare a composite conductive microfiltration (MF) membrane by introducing a stainless steel mesh into a polymeric MF membrane and to effectively control its fouling by applying an external electric field. Linear sweep voltammetry and electrochemical impedance spectroscopy analyses showed that this conductive membrane had very good electrochemical properties. Batch tests demonstrated its anti-fouling ability in filtration of bovine serum albumin, sodium alginate, humic acid and silicon dioxide particles as model foulants. The fouling rate in continuous-flow MBRs treating wastewater was also decreased by about 50% for this conductive membrane with 2 V/cm electric field compared to the control test during long-term operation. The enhanced electrostatic repulsive force between foulants and membrane, in-situ cleaning by H2O2 generated from oxygen reduction, and decreased production of soluble microbial products and extracellular polymeric substances contributed to fouling mitigation in this MBR. The results of this study shed light on the control strategy of membrane fouling for achieving a sustainable operation of MBRs.

  12. Impacts of sludge retention time on sludge characteristics and membrane fouling in a submerged osmotic membrane bioreactor.

    PubMed

    Wang, Xinhua; Chen, Yao; Yuan, Bo; Li, Xiufen; Ren, Yueping

    2014-06-01

    Sludge retention time (SRT) is a feasible method to alleviate the salt accumulation in the osmotic membrane bioreactor (OMBR) by discharging the waste activated sludge. In this study, effects of SRT on sludge characteristics and membrane fouling were investigated using a submerged OMBR under two SRTs of 10 and 15d. The results showed that the lower SRT was helpful for alleviating the salt accumulation and flux decline. Besides that, the removal of NH3-N was significantly influenced by SRT. SRT also had a strong effect on soluble microbial products (SMP) and microbial activity due to the variation of salinity. Microbial diversity analysis indicated that the high salinity environment in the OMBR significantly affected the microbial communities. The flux decline in the OMBR was mainly attributed to the reduced driving force resulting from the salt accumulation, and the reversible fouling was the dominant forward osmosis (FO) membrane fouling in the OMBR.

  13. Bacterial community structure of a lab-scale anammox membrane bioreactor.

    PubMed

    Gonzalez-Martinez, Alejandro; Osorio, F; Rodriguez-Sanchez, Alejandro; Martinez-Toledo, Maria Victoria; Gonzalez-Lopez, Jesus; Lotti, Tommaso; van Loosdrecht, M C M

    2015-01-01

    Autotrophic nitrogen removal technologies have proliferated through the last decade. Among these, a promising one is the membrane bioreactor (MBR) Anammox, which can achieve very high solids retention time and therefore sets a proper environment for the cultivation of anammox bacteria. In this sense, the MBR Anammox is an efficient technology for the treatment of effluents with low organic carbon and high ammonium concentrations once it has been treated under partial nitrification systems. A lab-scale MBR Anammox bioreactor has been built at the Technological University of Delft, The Netherlands and has been proven for efficient nitrogen removal and efficient cultivation of anammox bacteria. In this study, next-generation sequencing techniques have been used for the investigation of the bacterial communities of this MBR Anammox for the first time ever. A strong domination of Candidatus Brocadia bacterium and also the presence of a myriad of other microorganisms that have adapted to this environment were detected, suggesting that the MBR Anammox bioreactor might have a more complex microbial ecosystem that it has been thought. Among these, nitrate-reducing heterotrophs and primary producers, among others, were identified. Definition of the ecological roles of the OTUs identified through metagenomic analysis was discussed.

  14. Evaluation of membrane bioreactor for advanced treatment of industrial wastewater and reverse osmosis pretreatment

    PubMed Central

    2013-01-01

    The evaluation of a membrane bioreactor (MBR) for pretreatment of reverse osmosis (RO) in order to reuse and reclamation of industrial town wastewater treatment plant was investigated in this study. Performance of MBR effluent through water quality in term of parameters such as chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN) and total coliform (TC) were measured. Also Silt density index (SDI) was used as indicator for RO feed water. The results of this study demonstrated that MBR produce a high quality permeate water. Approximately 75%, 98%, 74% and 99.9% removal of COD, TSS, TN and TC were recorded, respectively. Also SDI of the permeate effluent from membrane was below 3 for most of the times. It means that pilot yield a high quality treated effluent from the membrane module which can be used as RO feed water. PMID:24355199

  15. Denitrification of drinking water in a two-stage membrane bioreactor by using immobilized biomass.

    PubMed

    Ravnjak, Matjaž; Vrtovšek, Janez; Pintar, Albin

    2013-01-01

    Nitrate removal from polluted groundwater was investigated in a two-stage anoxic/oxic biofilm membrane bioreactor. The process was carried out with ethanol as a carbon source (corresponding C/N ratio of 1.4-2.5) and commercially available Biocontact-N biocarriers (Nisshinbo, Japan) to enable immobilization of highly efficient and long-lasting microbiota. At a residence time of the liquid phase equal to 2.5h, nitrate conversions higher than 99% were obtained without the formation of nitrite and ammonium ions. The concentration of total organic carbon in the reactor discharge was very similar to the content of organic matter in tap water. The biocarriers minimized the occurrence of suspended filamentous bacteria, and the utilization of increased shear force facilitated collisions of floating biocarrier particles with the outer membrane surface, preventing membrane fouling and resulting in stable operation of the system for 40 days.

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

    PubMed

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

    2014-12-01

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

  17. Performance evaluation of attached growth membrane bioreactor for treating polluted surface water.

    PubMed

    Li, Lu; Suwanate, Siwaporn; Visvanathan, C

    2017-01-25

    Attached growth membrane bioreactor (aMBR) process was investigated for treating polluted surface water with CODMn around 10mg/L of raw water. Lab scale reactors, aMBR with 15% PVA-gel as carrier and conventional membrane filtration reactor (MF) were tested in parallel. aMBR achieved two times higher CODMn removal than MF system. Ammonia removal occurred almost completely in both MF and aMBR system - around 94% and 96%, respectively. Permeate turbidity was almost totally removed while UV254 removal was around 15% in MF and 20% in aMBR system. aMBR system largely mitigated membrane fouling and prolonged the system operation time. Results showed 2h hydraulic retention time provided relatively higher removal efficiency and stable operation performance. Modified Stover Kincannon model was able to match the aMBR system.

  18. Biodiesel production by microalgae cultivated using permeate from membrane bioreactors in continuous system.

    PubMed

    Low, Siok Ling; Ong, Say Leong; Ng, How Yong

    2014-01-01

    Microalgae in three submerged ceramic membrane photobioreactors (SCMPBRs) with different hydraulic retention times (HRTs) were fed with permeate of a submerged ceramic membrane bioreactor for a period of 3 months to investigate the lipid content and also the biodiesel quality produced at different HRTs. The lipid content, lipid productivity and fatty acid compositions for all three SCMPBRs were not significantly different at the 95% confidence level. These results suggested that insignificant change in the amount of fatty acids was observed at different HRTs that supplied varying concentration of nitrate in the medium. Among the fatty acids, palmitic acid, palmitoleic acid, oleic acid and linoleic acid were the main components, whereas stearic acid was a minor fatty acid. Since there was insignificant effect of HRT on lipid content, lipid productivity and fatty acid compositions, the optimum HRT for SCMPBRs can then be designed based on optimum nutrient removal performance and low membrane fouling propensity.

  19. Optimization Of The Alternate Cycle In A Membrane Aeration/Filtration Combined Bioreactor

    NASA Astrophysics Data System (ADS)

    Wang, Hongjie; Dong, Wenyi; Yang, Yue; Gan, Guanghua; Li, Weiguang

    2010-11-01

    In this study, a membrane aeration/filtration combined bioreactor (CMBR) was constructed, and the effect of alternate cycle by CMBR on membrane fouling and oxygen utilization efficiency (OUE) was investigated. Results showed that under the condition, when the alternate cycle was 0.75˜3h, the ΔTMP (TMP value of the time when a filtration cycle was over) of CMBR maintained a basically constant value during the 6 days' continuous operation, which implied the CMBR achieved a favorable effect of the membrane fouling relieving. Too short or too long cycle would lead to a gradual increase of ΔTMP. OUE of CMBR increased with the extension of the alternate cycle. Thus, it suggested that the optimal alternate cycle of CMBR should be 3h.

  20. Effect of powdered activated carbon on integrated submerged membrane bioreactor-nanofiltration process for wastewater reclamation.

    PubMed

    Woo, Yun Chul; Lee, Jeong Jun; Shim, Wang-Geun; Shon, Ho Kyong; Tijing, Leonard D; Yao, Minwei; Kim, Han-Seung

    2016-06-01

    The aim of this study was to determine the effect of powdered activated carbon (PAC) on the overall performance of a submerged membrane bioreactor (SMBR) system integrated with nanofiltration (NF) for wastewater reclamation. It was found that the trans-membrane pressure of SMBR increased continuously while that of the SMBR with PAC was more stable, mainly because water could still pass through the PACs and membrane even though foulants adhered on the PAC surface. The presence of PAC was able to mitigate fouling in SMBR as well as in NF. SMBR-NF with PAC obtained a higher flux of 8.1 LMH compared to that without PAC (6.6 LMH). In addition, better permeate quality was obtained with SMBR-NF integrated process added with PAC. The present results suggest that the addition of PAC in integrated SMBR-NF process could possibly lead to satisfying water quality and can be operated for a long-term duration.

  1. Stable aerobic granules in continuous-flow bioreactor with self-forming dynamic membrane.

    PubMed

    Liu, Hongbo; Li, Yajie; Yang, Changzhu; Pu, Wenhong; He, Liu; Bo, Fu

    2012-10-01

    A novel continuous-flow bioreactor with aerobic granular sludge and self-forming dynamic membrane (CGSFDMBR) was developed for efficient wastewater treatment. Under continuous-flow operation, aerobic granular sludge was successfully cultivated and characterized with small particle size of about 0.1-1.0mm, low settling velocity of about 15-25 m/h, loose structure and high water content of about 96-98%. To maintain the stability of aerobic granular sludge, strategies based on the differences of settling velocity and particle-size between granular and flocculent sludge were implemented. Moreover, in CGSFDMBR, membrane fouling was greatly relieved. Dynamic membrane was just cleaned once in more than 45 days' operation. CGSFDMBR presented good performance in treating septic tank wastewater, obtaining average COD, NH(4)(+)-N, TN and TP removal rates of 83.3%, 73.3%, 67.3% and 60%, respectively, which was more efficient than conventional bioreactors since that carbon, nitrogen and phosphorus were simultaneously removed in a single aerobic reactor.

  2. Mixing characterisation of full-scale membrane bioreactors: CFD modelling with experimental validation.

    PubMed

    Brannock, M; Wang, Y; Leslie, G

    2010-05-01

    Membrane Bioreactors (MBRs) have been successfully used in aerobic biological wastewater treatment to solve the perennial problem of effective solids-liquid separation. The optimisation of MBRs requires knowledge of the membrane fouling, biokinetics and mixing. However, research has mainly concentrated on the fouling and biokinetics (Ng and Kim, 2007). Current methods of design for a desired flow regime within MBRs are largely based on assumptions (e.g. complete mixing of tanks) and empirical techniques (e.g. specific mixing energy). However, it is difficult to predict how sludge rheology and vessel design in full-scale installations affects hydrodynamics, hence overall performance. Computational Fluid Dynamics (CFD) provides a method for prediction of how vessel features and mixing energy usage affect the hydrodynamics. In this study, a CFD model was developed which accounts for aeration, sludge rheology and geometry (i.e. bioreactor and membrane module). This MBR CFD model was then applied to two full-scale MBRs and was successfully validated against experimental results. The effect of sludge settling and rheology was found to have a minimal impact on the bulk mixing (i.e. the residence time distribution).

  3. [Comparison of sludge filtration characteristics between a membrane bioreactor and a conventional activated sludge process].

    PubMed

    Sun, Bao-sheng; Zhang, Hai-feng; Qi, Geng-shen

    2006-02-01

    According to the filtration characteristics of sludge, a comparison between a membrane bioreactor (MBR) and a conventional activated sludge process(CAS) was carried out under similar conditions. Experiment results show that the filtration resistance in MBR was 2 to approximately 3 times of that in CAS. The contribution of supernatant resistance to filtration resistance was about 90% both in CAS and in MBR. The test on resistance distribution showed the cake resistance made up 87.30% and 94.18% of total resistance in CAS and MBR, respectively.

  4. Application of electrochemical processes to membrane bioreactors for improving nutrient removal and fouling control.

    PubMed

    Borea, Laura; Naddeo, Vincenzo; Belgiorno, Vincenzo

    2017-01-01

    Membrane bioreactor (MBR) technology is becoming increasingly popular as wastewater treatment due to the unique advantages it offers. However, membrane fouling is being given a great deal of attention so as to improve the performance of this type of technology. Recent studies have proven that the application of electrochemical processes to MBR represents a promising technological approach for membrane fouling control. In this work, two intermittent voltage gradients of 1 and 3 V/cm were applied between two cylindrical perforated electrodes, immersed around a membrane module, at laboratory scale with the aim of investigating the treatment performance and membrane fouling formation. For comparison purposes, the reactor also operated as a conventional MBR. Mechanisms of nutrient removal were studied and membrane fouling formation evaluated in terms of transmembrane pressure variation over time and sludge relative hydrophobicity. Furthermore, the impact of electrochemical processes on transparent exopolymeric particles (TEP), proposed as a new membrane fouling precursor, was investigated in addition to conventional fouling precursors such as bound extracellular polymeric substances (bEPS) and soluble microbial products (SMP). All the results indicate that the integration of electrochemical processes into a MBR has the advantage of improving the treatment performance especially in terms of nutrient removal, with an enhancement of orthophosphate (PO4-P) and ammonia nitrogen (NH4-N) removal efficiencies up to 96.06 and 69.34 %, respectively. A reduction of membrane fouling was also observed with an increase of floc hydrophobicity to 71.72 %, a decrease of membrane fouling precursor concentrations, and, thus, of membrane fouling rates up to 54.33 %. The relationship found between TEP concentration and membrane fouling rate after the application of electrochemical processes confirms the applicability of this parameter as a new membrane fouling indicator.

  5. The effect of organic loading on bacterial community composition of membrane biofilms in a submerged polyvinyl chloride membrane bioreactor.

    PubMed

    Xia, Siqing; Li, Jixiang; He, Shuying; Xie, Kang; Wang, Xiaojia; Zhang, Yanhao; Duan, Liang; Zhang, Zhiqiang

    2010-09-01

    The effect of organic loading on bacterial community composition of membrane biofilms was investigated using a submerged polyvinyl chloride membrane bioreactor. The low and high loadings were set at 0.33 and 0.52 gCOD/(gVSSd), respectively. The results showed that membrane fouling occurred earlier and faster under the high loading conditions. Denaturing gradient gel electrophoresis (DGGE) analysis revealed that the similarity of bacterial community in the membrane biofilms between the two loadings was 0.67, higher than that in the mixed liquors (0.52-0.55), which indicated that some specific bacteria were selected preferentially on the membranes. Clone library analysis of the membrane biofilms indicated that Betaproteobacteria and Bacteroidetes under the high loading were 54.72% and 19.81%, respectively. Microarray results further confirmed that the two bacteria were the dominant microorganisms in the high loading biofilm. The severe membrane fouling may be aroused mainly by the enrichment of the two bacteria under the high loading.

  6. Influence of membrane fouling reducers (MFRs) on filterability of disperse mixed liquor of jet loop bioreactors.

    PubMed

    Koseoglu-Imer, Derya Yuksel; Dizge, Nadir; Karagunduz, Ahmet; Keskinler, Bulent

    2011-07-01

    The effects of membrane fouling reducers (MFRs) (the cationic polyelectrolyte (CPE) and FeCI(3)) on membrane fouling were studied in a lab-scale jet loop submerged membrane bioreactor (JL-SMBR) system. The optimum dosages of MFRs (CPE dosage=20 mg g(-1)MLSS, FeCI(3) dosage=14 mg g(-1)MLSS) were continuously fed to JL-SMBR system. The soluble and bound EPS concentrations as well as MLSS concentration in the mixed liquor of JL-SMBR were not changed substantially by the addition of MFRs. However, significant differences were observed in particle size and relative hydrophobicity. Filtration tests were performed by using different membrane types (polycarbonate (PC) and nitrocellulose mixed ester (ME)) and various pore sizes (0.45-0.22-0.1 μm). The steady state fluxes (J(ss)) of membranes increased at all membranes after MFRs addition to JL-SMBR. The filtration results showed that MFRs addition was an effective approach in terms of improvement in filtration performance for both membrane types.

  7. Characterization of biofouling in a lab-scale forward osmosis membrane bioreactor (FOMBR).

    PubMed

    Zhang, Qiaoyun; Jie, Yap Wei; Loong, Winson Lay Chee; Zhang, Jinsong; Fane, Anthony G; Kjelleberg, Staffan; Rice, Scott A; McDougald, Diane

    2014-07-01

    Forward osmosis membrane bioreactors (FOMBR) provide high quality permeate, however the propensity for membrane biofouling in FOMBRs is unknown. Here, FOMBRs were operated under high and low aeration and the membrane-associated biofilms were characterized by confocal laser scanning microscopy (CLSM) and rRNA gene-tagged pyrosequencing. CLSM images revealed that there was little biofilm formed under high aeration, while thick biofilms were observed on the membranes operated under low aeration. The diversity and richness of bacterial and archaeal communities as assessed by pyrosequencing varied under high and low aeration. The composition of the bacterial suspended sludge communities and the sessile biomass on the membrane surface, as assessed by non-metric multidimensional scaling, was significantly different under high aeration, but was more similar under low aeration. SIMPER analysis indicated that Pseudomonas, Aeromonas and Fluviicola preferentially attached to the membrane. The results presented here provide a comprehensive understanding of membrane biofouling in FOMBRs, which is essential for the development of effective control strategies.

  8. Anaerobic

    MedlinePlus

    ... shock. Anaerobic is the opposite of aerobic . In exercise, our bodies need to perform both anaerobic and aerobic reactions ... during shorter, more intense activities like sprinting. Anaerobic ... removing the lactic acid by providing oxygen to their bodies.

  9. Biological treatment of mixtures of toluene and n-hexane vapours in a hollow fibre membrane bioreactor.

    PubMed

    Zhao, Kang; Xiu, Guangli; Xu, Lihang; Zhang, Danian; Zhang, Xiaofeng; Deshusses, Marc A

    2011-04-01

    Membrane bioreactors are gaining interest for the control of contaminated air streams. In this study, the removal of toluene and n-hexane vapours in a hollow fibre membrane bioreactor (HFMB) was investigated. The focus was on quantifying the possible interactions occurring during the simultaneous biotreatment of the two volatile pollutants. Two lab-scale units fitted with microporous polypropylene hollow fibre membranes were connected in series and inoculated with activated sludge. Contaminated air was passed through the lumen at gas residence times ranging from 2.3 to 9.4 s while a pollutant-degrading biofilm developed on the shell side of the fibres. When toluene was treated alone, very high elimination capacities (up to 750 g m(-3) h(-1) based on lumen volume, or 1.25 g m(-2) h(-1) when normalized by the hollow fibre membrane area) were reached. When toluene and hexane were treated simultaneously, toluene biodegradation was partially inhibited by n-hexane, resulting in lower toluene removal rates. On the other hand, hexane removal was only marginally affected by the presence of toluene and was degraded at very high rates (upwards of 440 g m(-3) h(-1) or 0.73 g m(-2) h(-1) without breakthrough). Overall, this study demonstrates that mixtures of toluene and n-hexane vapours can be effectively removed in hollow fibre membrane bioreactors and that complex biological interactions may affect one or more of the pollutants undergoing treatment in gas-phase membrane bioreactors.

  10. Concurrent microbial reduction of high concentrations of nitrate and perchlorate in an ion exchange membrane bioreactor.

    PubMed

    Fox, Shalom; Bruner, Tali; Oren, Yoram; Gilron, Jack; Ronen, Zeev

    2016-09-01

    We investigated effective simultaneous removal of high loads of nitrate and perchlorate from synthetic groundwater using an ion exchange membrane bioreactor (IEMB). The aim of this research was to characterize both transport aspects and biodegradation mechanisms involved in the treatment process of high loads of the two anions. Biodegradation process was proven to be efficient with over 99% efficiency of both perchlorate and nitrate, regardless of their load. The maximum biodegradation rates were 18.3 (mmol m(-2)  h(-1) ) and 5.5 (mmol m(-2)  h(-1) ) for nitrate and perchlorate, respectively. The presence of a biofilm on the bio-side of the membrane only slightly increased the nitrate and perchlorate transmembrane flux as compared to the measured flux during a Donnan dialysis experiment where there is no biodegradation of perchlorate and nitrate in the bio-compartment. The nitrate flux in presence of a biofilm was 18.3 (±1.9) (mmole m(-2)  h(-1) ), while without the biofilm, the flux was 16.9 (±1.5) (mmole m(-2)  h(-1) ) for the same feed inlet nitrate concentration of 4 mM. The perchlorate transmembrane flux increased similarly by an average of 5%. Samples of membrane biofilm and suspended bacteria from the bio-reactor were analyzed for diversity and abundance of the perchlorate and nitrate reducing bacteria. Klebsiella oxytoca, known as a glycerol fermenter, accounted for 70% of the suspended bacteria. In contrast, perchlorate and nitrate reducing bacteria predominated in the biofilm present on the membrane. These results are consistent with our proposed two stage biodegradation mechanism where glycerol is first fermented in the suspended phase of the bio-reactor and the fermentation products drive perchlorate and nitrate bio-reduction in the biofilm attached to the membrane. These results suggest that the niche exclusion of microbial populations in between the reactor and membrane is controlled by the fluxes of the electron donors and

  11. A two-stage aerobic/anaerobic denitrifying horizontal bioreactor designed for treating ammonium and H(2)S simultaneously.

    PubMed

    Chinalia, F A; Garbossa, L H P; Rodriguez, J A; Lapa, K R; Foresti, E

    2012-11-01

    A two-stage bioreactor was operated for a period of 140 days in order to develop a post-treatment process based on anaerobic bioxidation of sulfite. This process was designed for simultaneously treating the effluent and biogas of a full-scale UASB reactor, containing significant concentrations of NH(4) and H(2)S, respectively. The system comprised of two horizontal-flow bed-packed reactors operated with different oxygen concentrations. Ammonium present in the effluent was transformed into nitrates in the first aerobic stage. The second anaerobic stage combined the treatment of nitrates in the liquor with the hydrogen sulfide present in the UASB-reactor biogas. Nitrates were consumed with a significant production of sulfate, resulting in a nitrate removal rate of 0.43 kgNm(3)day(-1) and ≥92 % efficiency. Such a removal rate is comparable to those achieved by heterotrophic denitrifying systems. Polymeric forms of sulfur were not detected (elementary sulfur); sulfate was the main product of the sulfide-based denitrifying process. S-sulfate was produced at a rate of about 0.35 kgm(3)day(-1). Sulfur inputs as S-H(2)S were estimated at about 0.75 kgm(3)day(-1) and Chemical Oxygen Demand (COD) removal rates did not vary significantly during the process. DGGE profiling and 16S rRNA identified Halothiobacillus-like species as the key microorganism supporting this process; such a strain has not yet been previously associated with such bioengineered systems.

  12. Iron and phosphorus speciation in Fe-conditioned membrane bioreactor activated sludge.

    PubMed

    Wu, Hao; Ikeda-Ohno, Atsushi; Wang, Yuan; Waite, T David

    2015-06-01

    Iron dosing of membrane bioreactors (MBRs) is widely used as a means of meeting effluent phosphorus targets but there is limited understanding of the nature of iron and phosphorus-containing solids that are formed within the bioreactor (an important issue in view of the increasing interest in recovering phosphorus from wastewaters). Of particular challenge is the complexity of the MBR system and the variety of reactions that can occur on addition of iron salts to a membrane bioreactor. In this study, the performances of bench scale MBRs with dosing of either ferrous or ferric salts were monitored for a period of four months. The distributions of Fe and P-species in the Fe-conditioned sludges were determined using X-ray absorption spectroscopy (XAS) at the Fe K-edge and the P K-edge. Regardless of whether iron was dosed to the anoxic or aerobic chambers and regardless of whether ferrous (Fe(II)) or ferric (Fe(III)) iron was dosed, iron present in the minerals in the conditioned sludges was consistently in the +III oxidation state. Fitting of the Fe K-edge EXAFS spectra revealed that an Fe(III)-phosphate species was the main Fe species present in all cases with the remaining fraction dominated by lepidocrocite (γ-FeOOH) in the Fe(II)-dosed case and ferrihydrite (am-FeOOH) in the Fe(III)-dosed case. Approximately half the phosphorus in the activated sludge samples was present as a distinct Fe-PO4 mineral (such as strengite or an amorphous ferric hydroxyl phosphate analogue of strengite) and half as phosphorus adsorbed to an iron oxyhydroxide mineral phase indicating that both co-precipitation and adsorption of phosphorus by iron contribute to removal of phosphorus from the MBR supernatant.

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

    PubMed

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

    2017-03-24

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

  14. Removal of pharmaceuticals and personal care products in a membrane bioreactor wastewater treatment plant.

    PubMed

    Kim, M; Guerra, P; Shah, A; Parsa, M; Alaee, M; Smyth, S A

    2014-01-01

    Ninety-nine pharmaceuticals and personal care products (PPCPs) were analyzed in influent, final effluent, and biosolids samples from a wastewater treatment plant employing a membrane bioreactor (MBR). High concentrations in influent were found for acetaminophen, caffeine, metformin, 2-hydroxy-ibuprofen, paraxanthine, ibuprofen, and naproxen (10(4)-10(5) ng/L). Final effluents contained clarithromycin, metformin, atenolol, carbamazepine, and trimethoprim (>500 ng/L) at the highest concentrations, while triclosan, ciprofloxacin, norfloxacin, triclocarban, metformin, caffeine, ofloxacin, and paraxanthine were found at high concentrations in biosolids (>10(3) ng/g dry weight). PPCP removals varied from -34% to >99% and 23 PPCPs had ≥90% removal. Of the studied PPCPs, 26 compounds have been rarely or never studied in previous membrane bioreactor (MBR) investigations. The removal pathway showed that acetaminophen, 2-hydroxy-ibuprofen, naproxen, ibuprofen, codeine, metformin, enalapril, atorvastatin, caffeine, paraxanthine, and cotinine exhibited high degradation/transformation. PPCPs showing strong sorption to solids included triclocarban, triclosan, miconazole, tetracycline, 4-epitetracycline, norfloxacin, ciprofloxacin, doxycycline, paroxetine, and ofloxacin. Trimethoprim, oxycodone, clarithromycin, thiabendazole, hydrochlorothiazide, erythromycin-H2O, carbamazepine, meprobamate, and propranolol were not removed during treatment, and clarithromycin was even formed during treatment. This investigation extended our understanding of the occurrence and fate of PPCPs in an MBR process through the analysis of the largest number of compounds in an MBR study to date.

  15. Evaluation of two pilot scale membrane bioreactors for the elimination of selected surfactants from municipal wastewaters

    NASA Astrophysics Data System (ADS)

    González, Susana; Petrovic, Mira; Barceló, Damiá

    2008-07-01

    SummaryThe removal of selected surfactants, linear alkylbenzene sulfonates (LAS), coconut diethanol amides (CDEA) and alkylphenol ethoxylates and their degradation products were investigated using a two membrane bioreactor (MBR) with hollow fiber and plate and frame membranes. The two pilot plants MBR run in parallel to a full-scale conventional activated sludge (CAS) treatment. A total of eight influent samples with the corresponding effluent samples were analysed by solid phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS-MS). The results indicate that both MBR have a better effluent quality in terms of chemical and biological oxygen demand (COD and BOD), NH4+ , concentration and total suspended solids (TSS). MBR showed a better similar performance in the overall elimination of the total nonylphenolic compounds, achieving a 75% of elimination or a 65% (the same elimination reached by CAS). LAS and CDEA showed similar elimination in the three systems investigated and no significant differences were observed.

  16. Membrane bioreactor: A mini review on recent R&D works.

    PubMed

    Huang, Liying; Lee, Duu-Jong

    2015-10-01

    Membrane bioreactor (MBR) has been widely applied worldwide in full scale. Recent research and development trends of MBR technology has been shifted from process optimization and economic evaluation to installation of new process architecture to enrich functional strains like nitrifiers or providing assisted field for performance enhancement, to incorporation of affordable adsorbents or scouring agent for membrane fouling mitigation, and to applying MBR hybrid systems for achieving simultaneous removals of nutrients and other pollutants. This mini-review summarized the recent works, principally in 2014-2015, on the above aspects, and provided a discussion on the osmotic MBR based on forward osmosis on its use of high-osmotic-pressure draw solution and the pre-treatment needed, and the reverse solute leakage that affects the MBR efficiency.

  17. Performance assessment of a submerged membrane bioreactor using a novel microbial consortium.

    PubMed

    Chon, Kangmin; Lee, Kyungpyo; Kim, In-Soo; Jang, Am

    2016-06-01

    The performance of a submerged membrane bioreactor (MBR) with and without a novel microbial consortium (NMBR vs. CMBR) was compared to provide deeper insights into the effects of changes in water quality and dissolved organic matter (DOM) characteristics by a novel microbial consortium on the fouling characteristics of MBR processes. Despite similar operating conditions and identical DOM properties in the feed waters, NMBR exhibited a lower propensity to release polysaccharide-like compounds with low molecular weight by bacterial activities compared to CMBR. These compounds have a great fouling potential for MBR processes. Therefore, an increase in the transmembrane pressure (TMP) of NMBR (normalized TMP (TMP/TMP0): 1.14) was much slower and less significant than that observed in CMBR (TMP/TMP0: 2.61). These observations imply that the novel microbial consortium can efficiently mitigate membrane fouling by hydrophilic DOM in MBR processes.

  18. A new flat sheet membrane bioreactor hybrid system for advanced treatment of effluent, reverse osmosis pretreatment and fouling mitigation.

    PubMed

    Hosseinzadeh, Majid; Bidhendi, Gholamreza Nabi; Torabian, Ali; Mehrdadi, Naser; Pourabdullah, Mehdi

    2015-09-01

    This paper introduces a new hybrid electro membrane bioreactor (HEMBR) for reverse osmosis (RO) pretreatment and advanced treatment of effluent by simultaneously integrating electrical coagulation (EC) with a membrane bioreactor (MBR) and its performance was compared with conventional MBR. Experimental results and their statistical analysis showed removal efficiency for suspended solids (SS) of almost 100% for both reactors. HEMBR removal of chemical oxygen demand (COD) improved by 4% and membrane fouling was alleviated according to transmembrane pressure (TMP). The average silt density index (SDI) of HEMBR permeate samples was slightly better indicating less RO membrane fouling. Moreover, based on the SVI comparison of two reactor biomass samples, HEMBR showed better settling characteristics which improved the dewaterability and filterability of the sludge. Analysis the change of membrane surfaces and the cake layer formed over them through field emission scanning electron microscopy (FESEM) and X-ray fluorescence spectrometer (XRF) were also discussed.

  19. Kinetics of nitrate and perchlorate removal and biofilm stratification in an ion exchange membrane bioreactor.

    PubMed

    Ricardo, Ana R; Carvalho, Gilda; Velizarov, Svetlozar; Crespo, João G; Reis, Maria A M

    2012-09-15

    The biological degradation of nitrate and perchlorate was investigated in an ion exchange membrane bioreactor (IEMB) using a mixed anoxic microbial culture and ethanol as the carbon source. In this process, a membrane-supported biofilm reduces nitrate and perchlorate delivered through an anion exchange membrane from a polluted water stream, containing 60 mg/L of NO₃⁻ and 100 μg/L of ClO₄⁻. Under ammonia limiting conditions, the perchlorate reduction rate decreased by 10%, whereas the nitrate reduction rate was unaffected. Though nitrate and perchlorate accumulated in the bioreactor, their concentrations in the treated water (2.8 ± 0.5 mg/L of NO₃⁻ and 7.0 ± 0.8 μg/L of ClO₄⁻, respectively) were always below the drinking water regulatory levels, due to Donnan dialysis control of the ionic transport in the system. Kinetic parameters determined for the mixed microbial culture in suspension showed that the nitrate reduction rate was 35 times higher than the maximum perchlorate reduction rate. It was found that perchlorate reduction was inhibited by nitrate, since after nitrate depletion perchlorate reduction rate increased by 77%. The biofilm developed in the IEMB was cryosectioned and the microbial population was analyzed by fluorescence in situ hybridization (FISH). The results obtained seem to indicate that the kinetic advantage of nitrate reduction favored accumulation of denitrifiers near the membrane, whereas per(chlorate) reducing bacteria were mainly positioned at the biofilm outer surface, contacting the biomedium. As a consequence of the biofilm stratification, the reduction of perchlorate and nitrate occur sequentially in space allowing for the removal of both ions in the IEMB.

  20. Long-Term n-Caproic Acid Production from Yeast-Fermentation Beer in an Anaerobic Bioreactor with Continuous Product Extraction.

    PubMed

    Ge, Shijian; Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

    2015-07-07

    Multifunctional reactor microbiomes can elongate short-chain carboxylic acids (SCCAs) to medium-chain carboxylic acids (MCCAs), such as n-caproic acid. However, it is unclear whether this microbiome biotechnology platform is stable enough during long operating periods to consistently produce MCCAs. During a period of 550 days, we improved the operating conditions of an anaerobic bioreactor for the conversion of complex yeast-fermentation beer from the corn kernel-to-ethanol industry into primarily n-caproic acid. We incorporated and improved in-line, membrane liquid-liquid extraction to prevent inhibition due to undissociated MCCAs at a pH of 5.5 and circumvented the addition of methanogenic inhibitors. The microbiome accomplished several functions, including hydrolysis and acidogenesis of complex organic compounds and sugars into SCCAs, subsequent chain elongation with undistilled ethanol in beer, and hydrogenotrophic methanogenesis. The methane yield was 2.40 ± 0.52% based on COD and was limited by the availability of carbon dioxide. We achieved an average n-caproate production rate of 3.38 ± 0.42 g L(-1) d(-1) (7.52 ± 0.94 g COD L(-1) d(-1)) with an n-caproate yield of 70.3 ± 8.81% and an n-caproate/ethanol ratio of 1.19 ± 0.15 based on COD for a period of ∼55 days. The maximum production rate was achieved by increasing the organic loading rates in tandem with elevating the capacity of the extraction system and a change in the complex feedstock batch.

  1. Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions.

    PubMed

    Espinosa-Solares, Teodoro; Bombardiere, John; Chatfield, Mark; Domaschko, Max; Easter, Michael; Stafford, David A; Castillo-Angeles, Saul; Castellanos-Hernandez, Nehemias

    2006-01-01

    Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9 x 10(6) t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m3 pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.

  2. Impact of dissolved oxygen concentration on membrane filtering resistance and soluble organic matter characteristics in membrane bioreactors.

    PubMed

    Min, Kyung-Nan; Ergas, Sarina J; Mermelstein, Anna

    2008-01-01

    This study investigated the impact of dissolved oxygen (DO) concentration on membrane filtering resistance, soluble organic matter (SOM) and extracellular polymeric substance (EPS) characteristics in a membrane bioreactor (MBR). A laboratory-scale MBR was operated under DO limited (0.2 mg L(-1) DO) and fully aerobic (3.7 and 5.4 mg L(-1) DO) conditions. Membrane filtering resistance was determined for the mixed liquor suspended solids (MLSS) and for resuspended microbial biomass after removing SOM. Regardless of the DO concentration, the cake resistance (Rc) was approximately 95 percent of the total resistance (Rt). The membrane cake resistance was found to decrease significantly after removing the SOM. The total resistance caused by the resuspended biomass was 29 percent of that caused by the MLSS under DO limited conditions, while the total resistance caused by resuspended biomass was 41 to 48 percent of that caused by the MLSS under fully aerobic conditions. Under DO limited conditions, SOM in the MLSS contained a larger amount of high molecular weight compounds, leading to higher cake resistance than under fully aerobic conditions. There was significant variation in the molecular weight fractions of the EPS, with no clear relationship with DO concentration. There was also no distinct relationship between membrane filtering resistance and molecular weight fraction of the EPS.

  3. Advanced Wastewater Treatment Engineering—Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling

    PubMed Central

    Paul, Parneet; Jones, Franck Anderson

    2016-01-01

    Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti’s RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation model based on first principles and traditional fouling mechanisms. In order to directly compare the potential benefits of this rotational system, this follow-up study was carried out using Avanti’s newly developed static (non-rotating) Flexidisks MBR system. The results from operating the static pilot unit were simulated and modelled using the rotational fouling model developed earlier however with rotational switching functions turned off and rotational parameters set to a static mode. The study concluded that a rotating MBR system could increase flux throughput when compared against a similar static system. It is thought that although the slowly rotating spindle induces a weak crossflow shear, it is still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded at the micro level and lessening the potential of rapid trans-membrane pressure increases at the macro level. PMID:26742053

  4. Advanced Wastewater Treatment Engineering-Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling.

    PubMed

    Paul, Parneet; Jones, Franck Anderson

    2016-01-05

    Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti's RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation model based on first principles and traditional fouling mechanisms. In order to directly compare the potential benefits of this rotational system, this follow-up study was carried out using Avanti's newly developed static (non-rotating) Flexidisks MBR system. The results from operating the static pilot unit were simulated and modelled using the rotational fouling model developed earlier however with rotational switching functions turned off and rotational parameters set to a static mode. The study concluded that a rotating MBR system could increase flux throughput when compared against a similar static system. It is thought that although the slowly rotating spindle induces a weak crossflow shear, it is still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded at the micro level and lessening the potential of rapid trans-membrane pressure increases at the macro level.

  5. Anaerobic digestion of the organic fraction of municipal solid waste in a two-stage membrane process.

    PubMed

    Trzcinski, A P; Stuckey, D C

    2009-01-01

    A batch of the Organic Fraction of Municipal Solid Waste (OFMSW) was treated in a two-step process with effluent recirculation comprising a novel hydrolytic reactor (HR) followed by a Submerged Anaerobic Membrane Bioreactor (SAMBR) operating at a stable permeate flux of 5.6 L/m(2) hr (LMH). A soluble COD removal higher than 95% was obtained from the SAMBR. The soluble COD as well as the Total Suspended Solids (TSS) did not build up due to efficient hydrolysis inside the SAMBR, and no VFA accumulation occurred due to the complete retention of methanogens by the membrane as well as the formation of syntrophic associations. Because of the microfiltration membrane in the second reactor a stabilized leachate was obtained from the very first days of the treatment and the highly stable process enabled shorter treatment periods compared to traditional leach bed processes. This experiment showed that the recycle of the stabilised leachate does not lead to a build up of SCOD. Size exclusion chromatography analysis confirmed that high molecular weight compounds were completely degraded and did not appear in the SAMBR permeate, and that low molecular weight fulvic-like and medium MW material were present in the permeate of the SAMBR but their concentration remained stable with time.

  6. Spatiotemporal dynamics and correlation networks of bacterial and fungal communities in a membrane bioreactor.

    PubMed

    Jeong, So-Yeon; Yi, Taewoo; Lee, Chung-Hak; Kim, Tae Gwan

    2016-11-15

    To systematically study biofilm communities responsible for biofouling in membrane bioreactors (MBRs), we characterized the spatiotemporal dynamics of bacterial and fungal biofilm communities, and their networks, in a pilot-scale flat-sheet MBR treating actual municipal wastewater. Activated sludge (AS) and membrane samples were collected on days 4 and 8. The membranes were cut into 18 tiles, and bacterial and fungal communities were analyzed using next generation sequencing. Nonmetric multidimensional scaling (NMDS) plots revealed significant temporal variations in bacterial and fungal biofilm communities due to changes in the abundances of a few dominant members. Although the experimental conditions and inoculum species pools remained constant, variogram plots of bacterial and fungal communities revealed decay in local community similarity with geographic distance at each sampling time. Variogram modeling (exponential rise to maximum, R(2) ≥ 0.79) revealed that decay patterns of both communities were different between days 4 and 8. In addition, networks of bacteria or fungi alone were distinct in network composition between days 4 and 8. The day-8 networks were more compact and clustered than those of the earlier time point. Bacteria-fungi networks show that the number of inter-domain associations decreased from 113 to 40 with time, confirming that membrane biofilm is a complex consortium of bacteria and fungi. Spatiotemporal succession in biofilm communities may be common on MBR membranes, resulting from different geographic distributions of initial microbial populations and their priority effects.

  7. Integration of micro-filtration into osmotic membrane bioreactors to prevent salinity build-up.

    PubMed

    Wang, Xinhua; Yuan, Bo; Chen, Yao; Li, Xiufen; Ren, Yueping

    2014-09-01

    The high salinity remains as one of major obstacles of the osmotic membrane bioreactor (OMBR). In this study, a new pathway was explored to prevent the salinity build-up by integrating the micro-filtration (MF) membrane to the OMBR (MF-OMBR). The results indicated that the salinity characterized by conductivity in the MF-OMBR was effectively alleviated and controlled at a lower value of about 5 mS/cm, and the stable flux of forward osmosis (FO) membrane correspondingly increased to approximately 5.5L/(m(2)h). Besides, the addition of MF membrane in the OMBR could increase the total organic carbon (TOC) and ammonium nitrogen (NH3-N) removals due to the activated sludge by improving the microbial activity. The membrane fouling especially the reversible fouling in the MF-OMBR was severer compared to that in the conventional OMBR, which resulted in a lower water flux than the expectation due to the increase of filtration resistance and external concentration polarization.

  8. High-rate, High Temperature Acetotrophic Methanogenesis Governed by a Three Population Consortium in Anaerobic Bioreactors

    PubMed Central

    Ho, Dang; Jensen, Paul; Gutierrez-Zamora, Maria-Luisa; Beckmann, Sabrina; Manefield, Mike; Batstone, Damien

    2016-01-01

    A combination of acetate oxidation and acetoclastic methanogenesis has been previously identified to enable high-rate methanogenesis at high temperatures (55 to 65°C), but this capability had not been linked to any key organisms. This study combined RNA–stable isotope probing on 13C-labelled acetate and 16S amplicon sequencing to identify the active micro-organisms involved in high-rate methanogenesis. Active biomass was harvested from three bench-scale thermophilic bioreactors treating waste activated sludge at 55, 60 and 65°C, and fed with 13-C labelled and 12C-unlabelled acetate. Acetate uptake and cumulative methane production were determined and kinetic parameters were estimated using model-based analysis. Pyrosequencing performed on 13C- enriched samples indicated that organisms accumulating labelled carbon were Coprothermobacter (all temperatures between 55 and 65°C), acetoclastic Methanosarcina (55 to 60°C) and hydrogenotrophic Methanothermobacter (60 to 65°C). The increased relative abundance of Coprothermobacter with increased temperature corresponding with a shift to syntrophic acetate oxidation identified this as a potentially key oxidiser. Methanosarcina likely acts as both a hydrogen utilising and acetoclastic methanogen at 55°C, and is replaced by Methanothermobacter as a hydrogen utiliser at higher temperatures. PMID:27490246

  9. Energy efficient of ethanol recovery in pervaporation membrane bioreactor with mechanical vapor compression eliminating the cold traps.

    PubMed

    Fan, Senqing; Xiao, Zeyi; Li, Minghai

    2016-07-01

    An energy efficient pervaporation membrane bioreactor with mechanical vapor compression was developed for ethanol recovery during the process of fermentation coupled with pervaporation. Part of the permeate vapor at the membrane downstream under the vacuum condition was condensed by running water at the first condenser and the non-condensed vapor enriched with ethanol was compressed to the atmospheric pressure and pumped into the second condenser, where the vapor was easily condensed into a liquid by air. Three runs of fermentation-pervaporation experiment have been carried out lasting for 192h, 264h and 360h respectively. Complete vapor recovery validated the novel pervaporation membrane bioreactor. The total flux of the polydimethylsiloxane (PDMS) membrane was in the range of 350gm(-2)h(-1) and 600gm(-2)h(-1). Compared with the traditional cold traps condensation, mechanical vapor compression behaved a dominant energy saving feature.

  10. Feasibility study to upgrade a textile wastewater treatment plant by a hollow fibre membrane bioreactor for effluent reuse.

    PubMed

    Malpei, F; Bonomo, L; Rozzi, A

    2003-01-01

    A pilot plant membrane bioreactor has been tested in parallel with a full-scale activated sludge wastewater treatment plant fed on the wastewater from a textile factory. The possibility to upgrade the final effluent for internal reuse was investigated. The pilot and full-scale plants are located in a textile factory (Boselli & C., Olgiate Comasco, North Italy) which manufactures and finishes polyester fabric. The activated sludge wastewater treatment plant (WWTP) is an extended aeration system. The MBR pilot plant is a ZW-10 bench hollow fibre module (membrane surface area: 0.93 m2) submerged in a 200 L tank. Performance and operation of the membrane bioreactor (MBR) were evaluated in terms of permeate characteristics and variability (COD, colour, total N and P, microbiological counts), of membrane specific flux (l m(-2) h(-1) bar(-1)) and other operational parameters (sludge growth and yield).

  11. Influence of COD:N ratio on sludge properties and their role in membrane fouling of a submerged membrane bioreactor.

    PubMed

    Hao, L; Liss, S N; Liao, B Q

    2016-02-01

    The effect of COD:N ratio on sludge properties and their role in membrane fouling were examined using a well-controlled aerobic membrane bioreactor receiving a synthetic high strength wastewater containing glucose. Membrane performance was improved with an increase in the COD/N ratio (100:5-100:1.8) (i.e. reduced N dosage). Surface analysis of sludge by X-ray photoelectron spectroscopy (XPS) indicates significant differences in surface concentrations of elements C, O and N that were observed under different COD/N ratios, implying changes in the composition of extracellular polymeric substances (EPS). Fourier transform-infrared spectroscopy (FTIR) revealed a unique characteristic peak (CO bonds) at 1735 cm(-1) under nitrogen limitation conditions. Total EPS decreased with an increase in COD/N ratio, corresponding to a decrease in the proteins (PN) to carbohydrates (CH) ratio in EPS. There were no significant differences in the total soluble microbial products (SMPs) but the ratio of PN/CH in SMPs decreased with an increase in COD/N ratios. The results suggest that EPS and SMP composition and the presence of a small quantity of filamentous microorganisms played an important role in controlling membrane fouling.

  12. Membrane bioreactors fed with different COD/N ratio wastewater: impacts on microbial community, microbial products, and membrane fouling.

    PubMed

    Han, Xiaomeng; Wang, Zhiwei; Ma, Jinxing; Zhu, Chaowei; Li, Yaxin; Wu, Zhichao

    2015-08-01

    It is known that an increase of COD/N ratio can result in an enhanced removal of nutrients in membrane bioreactors (MBRs); however, impacts of doing so on membrane filtration performance remain unclear. In this work, comparison of membrane filtration performance, microbial community, and microbial products under low temperature was carried out in anoxic/oxic (A/O) MBRs with COD/N ratios of 9.9 and 5.5 g COD/g N in influent. There was no doubt that an improvement of nitrogen removal under high COD/N ratio was observed; however, severer membrane fouling was found compared to the MBR fed with low COD/N ratio wastewater. The increase of COD/N ratio resulted in an elevated production of humic acids in soluble microbial product (SMP) and carbohydrates, proteins, and humic acids in loosely bound extracellular polymeric substance (LB-EPS). Quartz crystal microbalance with dissipation monitoring (QCM-D) analysis showed that the adsorption capability of SMP and LB-EPS was higher in the MBR with higher COD/N ratio. Four hundred fifty four high-throughput pyrosequencing revealed that the higher COD/N ratio led to the enrichment of Bacteroidetes at phylum level and Azospira, Thauera, Zoogloea, etc. at genus level. Bacteroidetes are considered to potentially release EPS, and Azospira, Thauera, and Zoogloea, etc. have denitrification activity. The change in microbial communities is consistent with MBR performance.

  13. Molecular weight distribution of a full-scale landfill leachate treatment by membrane bioreactor and nanofiltration membrane.

    PubMed

    Campagna, Marco; Cakmakcı, Mehmet; Yaman, F Büşra; Ozkaya, Bestamin

    2013-04-01

    In this study, Molecular weight (MW) distributions of a full-scale landfill leachate treatment plant consisting of membrane bioreactor (MBR) and nanofiltration (NF) membrane were investigated. The leachate was sampled from the equalization tank, and effluents of MBR and NF membrane in the landfill leachate treatment plant. Parameters of COD, TOC, TKN, NH4(+)-N and UV(254, 280 and 320) absorbance were analyzed to evaluate both the removal performance of the plant and MW distributions. MW distribution of samples were determined by ultrafiltration (UF) (100 kDa, 10 kDa, 5 kDa, 1 kDa and 500 Da) membranes. The results indicated that organic matter of one third percent is particulate or colloidal form and almost half of the organic fraction has a lower MW than 500 Da. In addition, organic matter had hydrophilic character. Most part of TKN was>500 Da with the corresponding rate of 92%. Further, UV absorbance of raw leachate (RW) decreased 85% after 500 Da.

  14. Impact of colloidal and soluble organic material on membrane performance in membrane bioreactors for municipal wastewater treatment.

    PubMed

    Rosenberger, S; Laabs, C; Lesjean, B; Gnirss, R; Amy, G; Jekel, M; Schrotter, J-C

    2006-02-01

    Two parallel membrane bioreactors (2 m3 each) were operated over a period of 2 years. Both pilots were optimised for nitrification, denitrification, and enhanced biological phosphorous elimination, treating identical municipal wastewater under comparable operating conditions. The only constructional difference between the pilots was the position of the denitrification zone (pre-denitrification in pilot 1 and post-denitrification in pilot 2). Despite identical modules and conditions, the two MBRs showed different permeabilities and fouling rates. The differences were not related to the denitrification scheme. In order to find an explanation for the different membrane performances, a one-year investigation was initiated and the membrane performance as well as the operating regime and characteristics of the activated sludge were closely studied. MLSS concentrations, solid retention time, loading rates, and filtration flux were found not to be responsible for the different performance of the submerged modules. These parameters were kept identical in the two pilot plants. Instead, the non-settable fraction of the sludges (soluble and colloidal material, i.e. polysaccharides, proteins and organic colloids) was found to impact fouling and to cause the difference in membrane performance between the two MBR. This fraction was analysed by spectrophotometric and size exclusion chromatography (SEC) methods. In a second step, the origin of these substances was investigated. The results point to microbiologically produced substances such as extracellular polymeric substances (EPS) or soluble microbial products (SMP).

  15. Effect of disintegrated sludge recycling on membrane permeability in a membrane bioreactor combined with a turbulent jet flow ozone contactor.

    PubMed

    Hwang, Byung-Kook; Kim, Jae-Hyuk; Ahn, Chang Hoon; Lee, Chung-Hak; Song, Jae-Yoon; Ra, Young-Hyun

    2010-03-01

    We have combined a turbulent jet flow ozone contactor (TJC) with a membrane bioreactor (MBR) to establish a zero-discharge system in terms of excess sludge in the MBR. The TJC-MBR system was compared with the conventional MBR (Control-MBR) with respect to i) the size and zeta potential of the sludge particles, ii) the loosely bound extra-cellular polymeric substances (EPSs) and tightly bound EPS of the microbial flocs, iii) the porosity and biovolume of the bio-cake accumulated on the membrane, and iv) the membrane permeability. The TJC system generated the ozonated sludge with a negligible amount of loosely bound EPS and a positive zeta potential. As a result, when such ozonated sludge was recycled, the average size of the sludge particles (e.g., microbial flocs) increased in the TJC-MBR. Consequently the bio-cake formed in the TJC-MBR had greater porosity than that in the Control-MBR, giving rise to higher membrane permeability in the TJC-MBR.

  16. Lipid production with Trichosporon oleaginosus in a membrane bioreactor using microalgae hydrolysate.

    PubMed

    Meo, Andrea; Priebe, Xenia Laura; Weuster-Botz, Dirk

    2017-01-10

    Lipid production by Trichosporon oleaginosus was first studied in fed-batch operated stirred-tank bioreactors on a milliliter- and liter-scale making use of typical sugar monomers and a sugar mixture that may be derived from microalgae biomass hydrolysis after the extraction of lipids. 20.3gL(-1) lipids (58% of dry cell mass) were produced with T. oleaginosus in a defined medium at nitrogen starvation in the fed-batch process with a typical microalgae derived carbohydrate mixture (60% glucose, 20% mannose, 20% galactose). Real microalgae hydrolysate resulted in superior growth of T. oleaginosus but no enhanced lipid formation was possible due to nitrogen and phosphorus excess in the hydrolysate. Phosphate precipitation and the application of a continuously operated membrane bioreactor with total cell retention due to the low sugar concentrations (∼40gL(-1)) in the microalgae hydrolysate resulted in the production of 30gL(-1) lipids (53% of dry cell mass) with T. oleaginosus at high space-time-yields of 0.33g lipids L(-1)h(-1). A high apparent lipid yield of 0.43g lipids g(-1) sugars consumed (130% of the theoretical maximum) was achieved with the microalgae hydrolysate most likely due to the additional conversion of other carbon sources (e.g. uronic acids, peptides) in the hydrolysate.

  17. High functional hollow fiber membrane modified with phospholipid polymers for a liver assist bioreactor.

    PubMed

    Ho Ye, Sang; Watanabe, Junji; Takai, Madoka; Iwasaki, Yasuhiko; Ishihara, Kazuhiko

    2006-03-01

    For practical application of a liver assist system with a tissue-conjugated hollow fiber membrane (HFM) bioreactor used in an extracorporeal therapy, it would require a highly sophisticated HFM which has both hemocompatibility on one side and cytocompatibility on the other side. In this study, we present a cellulose acetate (CA) HFM modified with 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers (PMB30 (MPC-co-n-butyl methacrylate) and PMA30 (MPC-co-methacrylic acid) for preparing a novel liver assist HFM bioreactor. A CA/PMB-PMA30 HFM modified asymmetrically on the inner and outer surface with the PMB30 and PMA30 was prepared successfully. Analysis with an X-ray photoelectron spectroscope showed that the intensity of the phosphorus atom attributed to the MPC units on the outer surface of the modified HFM was stronger than that of the inner surface. The PMA30 was immobilized on the outer surface of the CA/PMB30 blend HFM by a chemical condensation reaction. The CA/PMB-PMA30 HFM showed good water and solute permeability in comparison with the CA HFM. The morphologies of the adherent hepatocytes were round in shape in comparison with the cells that adhered on CA HFM. Furthermore, hepatocytes cultured on the inner surface of the CA/PMB-PMA30 HFM showed higher functional expression in terms of urea synthesis and albumin synthesis than that of the CA HFM.

  18. Impact of virus surface characteristics on removal mechanisms within membrane bioreactors.

    PubMed

    Chaudhry, Rabia M; Holloway, Ryan W; Cath, Tzahi Y; Nelson, Kara L

    2015-11-01

    In this study we investigated the removal of viruses with similar size and shape but with different external surface capsid proteins by a bench-scale membrane bioreactor (MBR). The goal was to determine which virus removal mechanisms (retention by clean backwashed membrane, retention by cake layer, attachment to biomass, and inactivation) were most impacted by differences in the virus surface properties. Seven bench-scale MBR experiments were performed using mixed liquor wastewater sludge that was seeded with three lab-cultured bacteriophages with icosahedral capsids of ∼30 nm diameter (MS2, phiX174, and fr). The operating conditions were designed to simulate those at a reference, full-scale MBR facility. The virus removal mechanism most affected by virus type was attachment to biomass (removals of 0.2 log for MS2, 1.2 log for phiX174, and 3 log for fr). These differences in removal could not be explained by electrostatic interactions, as the three viruses had similar net negative charge when suspended in MBR permeate. Removals by the clean backwashed membrane (less than 1 log) and cake layer (∼0.6 log) were similar for the three viruses. A comparison between the clean membrane removals seen at the bench-scale using a virgin membrane (∼1 log), and the full-scale using 10-year old membranes (∼2-3 logs) suggests that irreversible fouling, accumulated on the membrane over years of operation that cannot be removed by cleaning, also contributes towards virus removal. This study enhances the current mechanistic understanding of virus removal in MBRs and will contribute to more reliable treatment for water reuse applications.

  19. Role of initially formed cake layers on limiting membrane fouling in membrane bioreactors.

    PubMed

    Wu, Bing; Kitade, Tamotsu; Chong, Tzyy Haur; Uemura, Tadahiro; Fane, Anthony G

    2012-08-01

    In this study, an interesting phenomenon was observed that when the levels of soluble polysaccharides (SP) and soluble transparent exopolymer particles (sTEP) in the MBR unexpectedly and suddenly increased, the cleaned membranes tended to be more easily fouled compared to the membranes with the initial cake layers formed in a slow TMP increase stage. Foulant analysis indicated great accumulation amounts of SP and sTEP on the cleaned membrane. FT-IR spectra further confirmed that hydroxyl and amide groups in the soluble substances preferred to attach on the cleaned membranes. While, the initially formed cake layers on the membranes played a role to decrease zeta potential of cleaned membranes, which created less interaction with the soluble substances. It suggests that forming loose-structured cake layers on the primary membranes could be thought as an effective membrane fouling control strategy.

  20. Ethanol production in a membrane bioreactor: pilot-scale trials in a corn wet mill.

    PubMed

    Escobar, J M; Rane, K D; Cheryan, M

    2001-01-01

    Pilot plant trials were conducted in a corn wet mill with a 7000-L membrane recycle bioreactor (MRB) that integrated ceramic microfiltration membranes in a semi-closed loop configuration with a stirred-tank reactor. Residence times of 7.5-10 h with ethanol outputs of 10-11.5% (v/v) were obtained when the cell concentration was 60-100 g/L dry wt of yeast, equivalent to about 10(9)-10(10) cells/mL. The performance of the membrane was dependent on the startup mode and pressure management techniques. A steady flux of 70 L/(m2 x h) could be maintained for several days before cleaning was necessary. The benefits of the MRB include better productivity; a clear product stream containing no particulates or yeast cells, which should improve subsequent stripping and distillation operations; and substantially reduced stillage handling. The capital cost of the MRB is $21-$34/(m3 x yr) ($0.08-$0.13/[gal x yr]) of ethanol capacity. Operating cost, including depreciation, energy, membrane replacement, maintenance, labor, and cleaning, is $4.5-9/m3 ($0.017-$0.034/gal) of ethanol.

  1. RECYCLE AND REUSE OF CHARCOAL MADE FROM EXCESS SLUDGE IN MEMBRANE BIOREACTOR

    NASA Astrophysics Data System (ADS)

    Tran, Tuyet Thi; Shafiquzzaman, Md.; Nakajima, Jun

    Charcoal produced from excess sludge appeared to be useful for removing SMP (soluble microbial products) in MBR (membrane bioreactors) and therefore for reducing membrane fouling. Batch experiments and long-term MBR experiments were performed by using charcoal made of actual excess sludge. In the batch experiments, SMP was removed effectively through charcoal addition. This approach proved especially effective for the removal of carbohydrate. Charcoal would serve as an absorbent and coagulant in SMP removal. High BOD (biochemical oxygen demand) removal efficiencies produced no negative effects on biological activity in the reactors during the long-term MBR experiments involving charcoal addition. The decrease of humic substances and COD (chemical oxygen demand) through charcoal addition suggested that this approach effectively enhanced the performance of activated sludge treatment. A charcoal addition of more than 0.1% in long-term MBR experiments effectively decreased the membrane fouling frequency. The use of charcoal therefore served to mitigate membrane fouling. A decrease in carbohydrate, corresponding to the increase in the mean fouling period, suggested that a charcoal addition of more than 0.1% effectively removed SMP, especially carbohydrate. A charcoal cyclic reuse system is also proposed. This system would involve charcoal production and charcoal addition to MBR.

  2. BSM-MBR: a benchmark simulation model to compare control and operational strategies for membrane bioreactors.

    PubMed

    Maere, Thomas; Verrecht, Bart; Moerenhout, Stefanie; Judd, Simon; Nopens, Ingmar

    2011-03-01

    A benchmark simulation model for membrane bioreactors (BSM-MBR) was developed to evaluate operational and control strategies in terms of effluent quality and operational costs. The configuration of the existing BSM1 for conventional wastewater treatment plants was adapted using reactor volumes, pumped sludge flows and membrane filtration for the water-sludge separation. The BSM1 performance criteria were extended for an MBR taking into account additional pumping requirements for permeate production and aeration requirements for membrane fouling prevention. To incorporate the effects of elevated sludge concentrations on aeration efficiency and costs a dedicated aeration model was adopted. Steady-state and dynamic simulations revealed BSM-MBR, as expected, to out-perform BSM1 for effluent quality, mainly due to complete retention of solids and improved ammonium removal from extensive aeration combined with higher biomass levels. However, this was at the expense of significantly higher operational costs. A comparison with three large-scale MBRs showed BSM-MBR energy costs to be realistic. The membrane aeration costs for the open loop simulations were rather high, attributed to non-optimization of BSM-MBR. As proof of concept two closed loop simulations were run to demonstrate the usefulness of BSM-MBR for identifying control strategies to lower operational costs without compromising effluent quality.

  3. Pilot trial study of a compact macro-filtration membrane bioreactor process for saline wastewater treatment.

    PubMed

    Guan, Dao; Fung, W C; Lau, Frankie; Deng, Chao; Leung, Anthony; Dai, Ji; Chen, G H

    2014-01-01

    Conventional membrane bioreactor (MBR) systems have increasingly been studied in recent decades. However, their applications have been limited due to their drawbacks such as low flux, membrane fouling, and high operating cost. In this study, a compact macro-filtration MBR (MfMBR) process was developed by using a large pore size membrane to mitigate the membrane fouling problem. A pilot trial of MfMBR process was set up and operated to treat 10 m(3)/day of saline wastewater within 4 h. The system was operated under an average permeate flux of 13.1 m(3)/(m(2)·day) for 74 days. The average total suspended solids, total chemical oxygen demand, biological oxygen demand, total Kjeldahl nitrogen, and total nitrogen removal efficiencies achieved were 94.3, 83.1, 98.0, 93.1, and 63.3%, respectively, during steady-state operation. The confocal laser scanning microscopy image indicated that the backwash could effectively remove the bio-cake and dead bacteria. Thus, the results showed that the MfMBR process, which is essentially a primary wastewater treatment process, had the potential to yield the same high quality effluent standards as the secondary treatment process; thereby suggesting that it could be used as an option when the economic budget and/or land space is limited.

  4. Membrane Bioreactor/Ultra Low Energy Reverse Osmosis Membrane Process for Forward Operating Base Wastewater Reuse

    DTIC Science & Technology

    2014-08-01

    membranes in the test cells without recycling the permeate for 30 minutes to remove any residual chemicals and dyes. Afterwards, synthetic brackish water...The membrane performed consistently well over the entire study period with minimal membrane cleaning (Figure 75). The RO concentrate was recycled ...compared to the current practice of using bottled water. Assuming the same range of cost for membrane cleaning chemicals, Table 29 shows that the

  5. The Buoyant Filter Bioreactor: a high-rate anaerobic reactor for complex wastewater--process dynamics with dairy effluent.

    PubMed

    Haridas, Ajit; Suresh, S; Chitra, K R; Manilal, V B

    2005-03-01

    A novel high-rate anaerobic reactor, called "Buoyant Filter Bioreactor" (BFBR), has been developed for treating lipid-rich complex wastewater. The BFBR is able to decouple the biomass and insoluble COD retention time from the hydraulic retention time by means of a granular filter bed made of buoyant polystyrene beads. Filter clogging is prevented by an automatic backwash driven by biogas release, which fluidizes the granular filter bed in a downward direction. During filter backwash, the solids captured in the filter are reintroduced into the reaction zone of the reactor. The reaction zone is provided with a mixing system, which is independent of the hydraulic retention time. The performance of a laboratory-scale BFBR was studied for the treatment of dairy effluent, chosen as a model complex wastewater. The dairy effluent was not pre-treated for fat removal. The BFBR was operated over 400 d and showed greater than 85% COD removal at 10 kg COD/(m3/d). The COD conversion to methane in the BFBR was essentially complete. The BFBR performance improved with age, and with feed containing 3200 mg COD/l, the treated effluent had 120 mg COD/l and no turbidity. The hold-up of degradable biosolids, including scum, inside the BFBR was estimated using starvation tests. When load is increased, scum accumulates inside the BFBR and then decays after undergoing change from hydrophobic to hydrophilic. This is explained as the accumulation of fat solids, its conversion to insoluble long chain fatty acids and its further solubilization and degradation.

  6. Microbial dynamics in upflow anaerobic sludge blanket (UASB) bioreactor granules in response to short-term changes in substrate feed

    SciTech Connect

    Kovacik, William P.; Scholten, Johannes C.; Culley, David E.; Hickey, Robert; Zhang, Weiwen; Brockman, Fred J.

    2010-08-01

    The complexity and diversity of the microbial communities in biogranules from an upflow anaerobic sludge blanket (UASB) bioreactor were determined in response to short-term changes in substrate feeds. The reactor was fed simulated brewery wastewater (SBWW) (70% ethanol, 15% acetate, 15% propionate) for 1.5 months (phase 1), acetate / sulfate for 2 months (phase 2), acetate-alone for 3 months (phase 3), and then a return to SBWW for 2 months (phase 4). Performance of the reactor remained relatively stable throughout the experiment as shown by COD removal and gas production. 16S rDNA, methanogen-associated mcrA and sulfate reducer-associated dsrAB genes were PCR amplified, then cloned and sequenced. Sequence analysis of 16S clone libraries showed a relatively simple community composed mainly of the methanogenic Archaea (Methanobacterium and Methanosaeta), members of the Green Non-Sulfur (Chloroflexi) group of Bacteria, followed by fewer numbers of Syntrophobacter, Spirochaeta, Acidobacteria and Cytophaga-related Bacterial sequences. Methanogen-related mcrA clone libraries were dominated throughout by Methanobacter and Methanospirillum related sequences. Although not numerous enough to be detected in our 16S rDNA libraries, sulfate reducers were detected in dsrAB clone libraries, with sequences related to Desulfovibrio and Desulfomonile. Community diversity levels (Shannon-Weiner index) generally decreased for all libraries in response to a change from SBWW to acetate-alone feed. But there was a large transitory increase noted in 16S diversity at the two-month sampling on acetate-alone, entirely related to an increase in Bacterial diversity. Upon return to SBWW conditions in phase 4, all diversity measures returned to near phase 1 levels.

  7. Microbial adaptation to biodegrade toxic organic micro-pollutants in membrane bioreactor using different sludge sources.

    PubMed

    Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2014-08-01

    Biodegradation of toxic organic micro-pollutants in municipal solid waste (MSW) leachate by membrane bioreactor (MBR) was investigated. The MBR systems were seeded with different sludge sources, one was from a pilot-scale MBR system treating MSW leachate and the other was from an activated sludge sewage treatment plant. The biodegradation of BPA, 2,6-DTBP, BHT, DEP, DBP and DEHP, DCP and BBzP, by sludge from both reactors were found improved with time. However, enhanced biodegradation of micro-pollutants was observed in MBR operated under long sludge age condition. Bacterial population analyses determined by PCR-DGGE revealed the development of phenol and phthalate degrading bacteria consortium in MBR sludge during its operation.

  8. Design, analysis and validation of a simple dynamic model of a submerged membrane bioreactor.

    PubMed

    Pimentel, Guilherme A; Vande Wouwer, Alain; Harmand, Jérôme; Rapaport, Alain

    2015-03-01

    In this study, a simple dynamic model of a submerged membrane bioreactor (sMBR) is proposed, which would be suitable for process control. In order to validate the proposed model structure, informative data sets are generated using a detailed simulator built in a well-established environment, namely GPS-X. The model properties are studied, including equilibrium points, stability, and slow/fast dynamics (three different time scales). The existence of slow-fast dynamics is central to the development of a dedicated parameter estimation procedure. Finally, a nonlinear model predictive control is designed to illustrate the potential of the developed model within a model-based control structure. The problem of water treatment in a recirculating aquaculture system is considered as an application example.

  9. 2-Chlorobenzoate biodegradation by recombinant Burkholderia cepacia under hypoxic conditions in a membrane bioreactor.

    PubMed

    Urgun-Demirtas, Meltem; Stark, Benjamin; Pagilla, Krishna

    2005-01-01

    The feasibility of applying bacterial hemoglobin technology to degrade 2-chlorobenzoate (2-CBA) through co-metabolism under hypoxic conditions in a membrane bioreactor (MBR) process has been studied in the laboratory. 2-chlorobenzoate removal and chloride release rates in the MBR system varied from 99 to 78% and 98 to 73%, respectively, depending on the operation conditions. Chemical oxygen demand (COD) removal efficiencies were more than 90% at food-to-microorganism ratios ranging from 0.32 to 0.62 g/g/d, and the observed yield was 0.13 to 0.20 g biomass/g COD. The bacterial cell-floc size-distribution analysis showed that there is a significant change in bacterial floc size due to high shear stress during operation of the MBR. To characterize growth kinetics of Burkholderia cepacia strain dinitrotoluene, a mathematical model that describes co-metabolic oxidation of 2-CBA in an MBR has been developed.

  10. A Novel Electrochemical Membrane Bioreactor as a Potential Net Energy Producer for Sustainable Wastewater Treatment

    PubMed Central

    Wang, Yun-Kun; Sheng, Guo-Ping; Shi, Bing-Jing; Li, Wen-Wei; Yu, Han-Qing

    2013-01-01

    One possible way to address both water and energy shortage issues, the two of major global challenges, is to recover energy and water resource from wastewater. Herein, a novel electrochemical membrane bioreactor (EMBR) was developed to recover energy from wastewater and meantime harvest clean water for reuse. With the help of the microorganisms in the biocatalysis and biodegradation process, net electricity could be recovered from a low-strength synthetic wastewater after estimating total energy consumption of this system. In addition, high-quality clean water was obtained for reuse. The results clearly demonstrate that, under the optimized operating conditions, it is possible to recover net energy from wastewater, while at the same time to harvest high-quality effluent for reuse with this novel wastewater treatment system. PMID:23689529

  11. Enhanced biological phosphorus removal and its modeling for the activated sludge and membrane bioreactor processes.

    PubMed

    Zuthi, M F R; Guo, W S; Ngo, H H; Nghiem, L D; Hai, F I

    2013-07-01

    A modified activated sludge process (ASP) for enhanced biological phosphorus removal (EBPR) needs to sustain stable performance for wastewater treatment to avoid eutrophication in the aquatic environment. Unfortunately, the overall efficiency of the EBPR in ASPs and membrane bioreactors (MBRs) is frequently hindered by different operational/system constraints. Moreover, although phosphorus removal data from several wastewater treatment systems are available, a comprehensive mathematical model of the process is still lacking. This paper presents a critical review that highlights the core issues of the biological phosphorus removal in ASPs and MBRs while discussing the inhibitory process requirements for other nutrients' removal. This mini review also successfully provided an assessment of the available models for predicting phosphorus removal in both ASP and MBR systems. The advantages and limitations of the existing models were discussed together with the inclusion of few guidelines for their improvement.

  12. Hydrogenotrophic denitrification of highly saline aquaculture wastewater using hollow fiber membrane bioreactor.

    PubMed

    Visvanathan, C; Phong, D D; Jegatheesan, V

    2008-06-01

    A hydrogenotrophic denitrification system with a hollow fiber membrane was evaluated for treating and recycling synthetic aquaculture wastewater. Hollow fibers ensured bubble-less diffusion of hydrogen and subsequent removal of nitrate from the first bioreactor. The second aerobic reactor was used for biomass filtration and removal of organic matter. Nitrate and organic matter expressed as dissolved organic carbon were 50 mgl(-1) and 20 mgl(-1), respectively, in the inlet. Acclimatization of hydrogenotrophic bacteria to 10, 20 and 30 ppt of salinity was also observed. Optimum hydraulic retention time and denitrification rate corresponding to these salinities were 3, 5 and 6 h and 366.8, 226.2 and 193.2 gm(-3) day(-1), respectively.

  13. Optimization of membrane bioreactors by the addition of powdered activated carbon.

    PubMed

    Ng, Choon Aun; Sun, Darren; Bashir, Mohammed J K; Wai, Soon Han; Wong, Ling Yong; Nisar, Humaira; Wu, Bing; Fane, Anthony G

    2013-06-01

    It was found that with replenishment, powdered activated carbon (PAC) in the membrane bioreactor (MBR) would develop biologically activated carbon (BAC) which could enhance filtration performance of a conventional MBR. This paper addresses two issues (i) effect of PAC size on MBR (BAC) performance; and (ii) effect of sludge retention time (SRT) on the MBR performance with and without PAC. To interpret the trends, particle/floc size, concentration of mixed liquor suspended solid (MLSS), total organic carbon (TOC), short-term filtration properties and transmembrane pressure (TMP) versus time are measured. The results showed improved fouling control with fine, rather than coarse, PAC provided the flux did not exceed the deposition flux for the fine PAC. Without PAC, the longer SRT operation gave lower fouling at modest fluxes. With PAC addition, the shorter SRT gave better fouling control, possibly due to greater replenishment of the fresh PAC.

  14. A novel electrochemical membrane bioreactor as a potential net energy producer for sustainable wastewater treatment.

    PubMed

    Wang, Yun-Kun; Sheng, Guo-Ping; Shi, Bing-Jing; Li, Wen-Wei; Yu, Han-Qing

    2013-01-01

    One possible way to address both water and energy shortage issues, the two of major global challenges, is to recover energy and water resource from wastewater. Herein, a novel electrochemical membrane bioreactor (EMBR) was developed to recover energy from wastewater and meantime harvest clean water for reuse. With the help of the microorganisms in the biocatalysis and biodegradation process, net electricity could be recovered from a low-strength synthetic wastewater after estimating total energy consumption of this system. In addition, high-quality clean water was obtained for reuse. The results clearly demonstrate that, under the optimized operating conditions, it is possible to recover net energy from wastewater, while at the same time to harvest high-quality effluent for reuse with this novel wastewater treatment system.

  15. Fate of copper in submerged membrane bioreactors treating synthetic municipal wastewater.

    PubMed

    Nakhla, George; Holakoo, Ladan; Yanful, Ernest; Bassi, Amarjeet

    2008-05-30

    This paper assesses the impact of copper on the performance of two membrane bioreactors (MBR) treating municipal wastewater at a hydraulic retention time (HRT) of 4h, and solids residence times (SRT) of 20 days, at influent copper concentrations of 0.2-8 mg Cu/L. The addition of copper resulted in a significant increase in soluble microbial products (SMPs), and a predominance of >100 kDa molecular weight SMPs. The study showed that in well-buffered wastewaters, complete nitrification was achieved at total copper concentrations as high as 840 mg/L or 10% of the mixed liquor volatile suspended solids. MINTEQ simulation showed that most of the copper (99.8%) in the MBR was in the form of inorganic copper precipitates, with free Cu2+ and total soluble copper in the range of 0.0-0.11 and 0.1-0.82 mg/L, respectively.

  16. Population dynamics in bioaugmented membrane bioreactor for treatment of bromoamine acid wastewater.

    PubMed

    Qu, Yuan-Yuan; Zhou, Ji-Ti; Wang, Jing; Xing, Lin-Lin; Jiang, Nan; Gou, Min; Salah Uddin, M

    2009-01-01

    The performances and microbial population changes in laboratory-scale membrane bioreactor (MBR) augmented with Sphingomonas xenophaga QYY were investigated in the present study. It was demonstrated that after 30 days acclimation, the non-augmented MBR system were able to degrade bromoamine acid (BAA) well. However, the efficiency of the system decreased with BAA concentration increasing. While the augmented MBR showed higher capability, in which the color and COD removal were more than 90% and 50%, respectively. By ribosomal intergenic spacer analysis (RISA), it was found that BAA-utilizing populations gradually increased to become the dominant species in the non-augmented MBR. However, the augmented MBR possessed relatively stable treatment abilities, in which the introduced strain QYY could be persistent and co-exist well with the indigenous populations.

  17. Evaluation of energy-distribution of a hybrid microbial fuel cell-membrane bioreactor (MFC-MBR) for cost-effective wastewater treatment.

    PubMed

    Wang, Jie; Bi, Fanghua; Ngo, Huu-Hao; Guo, Wenshan; Jia, Hui; Zhang, Hongwei; Zhang, Xinbo

    2016-01-01

    A low-cost hybrid system integrating a membrane-less microbial fuel cell (MFC) with an anoxic/oxic membrane bioreactor (MBR) was studied for fouling mitigation. The appended electric field in the MBR was supplied by the MFC with continuous flow. Supernatant from an anaerobic reactor with low dissolved oxygen was used as feed to the MFC in order to enhance its performance compared with that fed with synthetic wastewater. The voltage output of MFC maintained at 0.52±0.02V with 1000Ω resister. The electric field intensity could reach to 0.114Vcm(-1). Compared with the conventional MBR (CMBR), the contents rather than the components of foulants on the cake layer of fouled MFC-MBR system was significantly reduced. Although only 0.5% of the feed COD was translated into electricity and applied to MBR, the hybrid system showed great feasibility without additional consumption but extracting energy from waste water and significantly enhancing the membrane filterability.

  18. Removal of trace organic chemicals and performance of a novel hybrid ultrafiltration-osmotic membrane bioreactor.

    PubMed

    Holloway, Ryan W; Regnery, Julia; Nghiem, Long D; Cath, Tzahi Y

    2014-09-16

    A hybrid ultrafiltration-osmotic membrane bioreactor (UFO-MBR) was investigated for over 35 days for nutrient and trace organic chemical (TOrC) removal from municipal wastewater. The UFO-MBR system uses both ultrafiltration (UF) and forward osmosis (FO) membranes in parallel to simultaneously extract clean water from an activated sludge reactor for nonpotable (or environmental discharge) and potable reuse, respectively. In the FO stream, water is drawn by osmosis from activated sludge through an FO membrane into a draw solution (DS), which becomes diluted during the process. A reverse osmosis (RO) system is then used to reconcentrate the diluted DS and produce clean water suitable for direct potable reuse. The UF membrane extracts water, dissolved salts, and some nutrients from the system to prevent their accumulation in the activated sludge of the osmotic MBR. The UF permeate can be used for nonpotable reuse purposes (e.g., irrigation and toilet flushing). Results from UFO-MBR investigation illustrated that the chemical oxygen demand, total nitrogen, and total phosphorus removals were greater than 99%, 82%, and 99%, respectively. Twenty TOrCs were detected in the municipal wastewater that was used as feed to the UFO-MBR system. Among these 20 TOrCs, 15 were removed by the hybrid UFO-MBR system to below the detection limit. High FO membrane rejection was observed for all ionic and nonionic hydrophilic TOrCs and lower rejection was observed for nonionic hydrophobic TOrCs. With the exceptions of bisphenol A and DEET, all TOrCs that were detected in the DS were well rejected by the RO membrane. Overall, the UFO-MBR can operate sustainably and has the potential to be utilized for direct potable reuse applications.

  19. Elucidation of nitrate reduction pathways in anaerobic bioreactors using a stable isotope approach.

    PubMed

    Mazéas, Laurent; Vigneron, Vassilia; Le-Ménach, Karyn; Budzinski, Hélène; Audic, Jean-Marc; Bernet, Nicolas; Bouchez, Théodore

    2008-06-01

    Leachate recirculation allows an increase of moisture content and the enhancement of the anaerobic digestion of wastes in landfill. Since there is no ammonia elimination process in landfill when leachate is recirculated, NH(4) (+) may accumulate. One strategy for NH(4) (+) removal is to treat aerobically the leachate outside the landfill to convert NH(4) (+) into NO(3) (-). When nitrified leachate is recirculated, denitrification should occur in the waste. We have previously shown that wastes have a large capacity to convert nitrate into N(2). Nevertheless, in some cases we observed nitrate reduction without gaseous nitrogen production. Using a stepwise multiple regression models, H(2)S concentration was the unique parameter found to have a negative effect on N(2) production. We then suspected that dissimilatory nitrate reduction to ammonium (DNRA) occurred in the presence of H(2)S. In order to verify this hypothesis, (15)N nitrate injections were performed into microcosms containing different H(2)S concentrations. The ammonium (15)N enrichment was measured using an elemental analyser coupled to an isotope ratio mass spectrometer. In the two microcosms containing the highest H(2)S concentrations, the ammonium was (15)N enriched and at the end of the experiment all the added nitrate was converted into ammonium. For the two microcosms containing the lowest H(2)S concentrations, no (15)N enrichment of ammonium was observed. This isotopic approach has allowed us to demonstrate that, in the presence of significant concentrations of H(2)S, denitrification is replaced by DNRA.

  20. Nitrogen and phosphorus removal in an airlift intermittent circulation membrane bioreactor.

    PubMed

    Guo, Haiyan; Chen, Jiandong; Li, Yun; Feng, Tengteng; Zhang, Shoutong

    2013-12-01

    A new airlift intermittent circulation integrated bioreactor was developed for simultaneous nitrogen and phosphorus removal of wastewater, in which, circulation of mixed liquid between mixing zone and aeration zone was realized by aeration power, alternately anaerobic/anoxic bio-environment in mixing zone was realized by intermittent circulation and simultaneous nitrogen and phosphorus removal was obtained through strengthened denitrifying phosphorus removal process. Removal performance of the reactor was investigated and pollutant removal and transfer mechanism in one operation circle was analyzed. The experiment results indicated that under the influent condition of chemical oxygen demand (COD) concentration of 642.1 mg/L, total nitrogen (TN) of 87.4 mg/L and PO4(3-)-P of 12.1 mg/L, average removal efficiencies of COD, TN and PO4(3-)-P reached 96.4%, 83.2% and 90.5%, respectively, with the hydraulic residence time of 22 hr and operation circle time of 185 min. Track studies indicated that the separation of aeration and mixing zones and intermittent circulation of mixed liquid between the two zones provided distinct biological environments spatially and temporally, which ensured the occurrence of multifunctional microbial reactions.

  1. Multimembrane Bioreactor

    NASA Technical Reports Server (NTRS)

    Cho, Toohyon; Shuler, Michael L.

    1989-01-01

    Set of hydrophilic and hydrophobic membranes in bioreactor allows product of reaction to be separated, while nutrients fed to reacting cells and byproducts removed from them. Separation process requires no externally supplied energy; free energy of reaction sufficient. Membranes greatly increase productivity of metabolizing cells by continuously removing product and byproducts, which might otherwise inhibit reaction, and by continuously adding oxygen and organic nutrients.

  2. Validation of a full-scale membrane bioreactor and the impact of membrane cleaning on the removal of microbial indicators.

    PubMed

    van den Akker, Ben; Trinh, Trang; Coleman, Heather M; Stuetz, Richard M; Le-Clech, Pierre; Khan, Stuart J

    2014-03-01

    The removal of microbial indicators through a full-scale membrane bioreactor (MBR) was characterised. The overall log reduction of Escherichia coli and total coliforms were in the range of 5.0-5.9log10 units, while the reduction of clostridia was marginally less at 4.9log10 units. Removal of bacteriophage was in excess of 4.6log10 units. The impact of membrane cleaning on the elimination of microbial indicators was also assessed since this had been identified by pilot-scale studies as a potential hazardous event. Membrane cleaning temporarily reduced the log removal values of E. coli and total coliforms each by 1log10 unit, but did not affect the removal of bacteriophage or clostridia. Very little research has previously examined the consequences of hazardous events on the performance of full-scale MBRs, and thus the findings presented here will facilitate improvements for the risk assessment and management of MBRs used in water recycling schemes.

  3. Microbial responses to membrane cleaning using sodium hypochlorite in membrane bioreactors: Cell integrity, key enzymes and intracellular reactive oxygen species.

    PubMed

    Han, Xiaomeng; Wang, Zhiwei; Wang, Xueye; Zheng, Xiang; Ma, Jinxing; Wu, Zhichao

    2016-01-01

    Sodium hypochlorite (NaClO) is a commonly used reagent for membrane cleaning in membrane bioreactors (MBRs), while it, being a kind of disinfectant (oxidant), may impair viability of microbes or even totally inactivate them upon its diffusion into mixed liquor during membrane cleaning. In this study, we systematically examine the effects of NaClO on microorganisms in terms of microbial cell integrity, metabolism behaviours (key enzymes), and intracellular reactive oxygen species (ROS) under various NaClO concentrations. Different proportions of microbial cells in activated sludge were damaged within several minutes dependent on NaClO dosages (5-50 mg/g-SS), and correspondingly organic matters were released to bulk solution. Inhibition of key enzymes involved in organic matter biodegradation, nitrification and denitrification was observed in the presence of NaClO above 1 mg/g-SS, and thus organic matter and nitrogen removal efficiencies were decreased. It was also demonstrated that intracellular ROS production was increased with the NaClO dosage higher than 1 mg/g-SS, which likely induced further damage to microbial cells.

  4. Continuous treatment of the organic fraction of municipal solid waste in an anaerobic two-stage membrane process with liquid recycle.

    PubMed

    Trzcinski, A P; Stuckey, D C

    2009-05-01

    The stability and performance of a two-stage anaerobic membrane process was investigated at different organic loading rates (OLRs) and Hydraulic Retention Times (HRTs) over 200 days. The Hydrolytic Reactor (HR) was fed with the Organic Fraction of Municipal Solid Waste (OFMSW), while the leachate from the HR was fed continuously to two Submerged Anaerobic Membrane Bioreactors (SAMBR1 and 2). The Total COD (TCOD) of the leachate varied over a wide range, typically between 4000 and 26,000 mg/L while the Soluble COD (SCOD) in the permeate was in the range 400-600 mg/L, achieving a COD removal greater than 90% at a HRT of 1.6-2.3 days in SAMBR1. The operation was not sustainable below this HRT due to a membrane flux limitation at 0.5-0.8L/m(2) h (LMH), which was linked to the increasing MLTSS. SCOD in the recycled permeate did not build up indicating a slow degradation of recalcitrants over time. SAMBR2 was run in parallel with SAMBR1 but its permeate was treated aerobically in an Aerobic Membrane Bioreactor (AMBR). The AMBR acted as a COD-polishing and ammonia removal step. About 26% of the recalcitrant SCOD from SAMBR2 could be aerobically degraded in the AMBR. In addition, 97.7 % of the ammonia-nitrogen was converted to nitrate in the AMBR at a maximum nitrogen-loading rate of 0.18 kg NH(4)(+)-N/m(3) day. GC-MS analysis was performed on the reactor effluents to determine their composition and what compounds were recalcitrant.

  5. Development and Testing of a Fully Adaptable Membrane Bioreactor Fouling Model for a Sidestream Configuration System

    PubMed Central

    Paul, Parneet

    2013-01-01

    A dead-end filtration model that includes the three main fouling mechanisms mentioned in Hermia (i.e., cake build-up, complete pore blocking, and pore constriction) and that was based on a constant trans-membrane pressure (TMP) operation was extensively modified so it could be used for a sidestream configuration membrane bioreactor (MBR) situation. Modifications and add-ons to this basic model included: alteration so that it could be used for varying flux and varying TMP operations; inclusion of a backwash mode; it described pore constriction (i.e., irreversible fouling) in relation to the concentration of soluble microbial products (SMP) in the liquor; and, it could be used in a cross flow scenario by the addition of scouring terms in the model formulation. The additional terms in this modified model were checked against an already published model to see if they made sense, physically speaking. Next this modified model was calibrated and validated in Matlab© using data collected by carrying out flux stepping tests on both a pilot sidestream MBR plant, and then a pilot membrane filtration unit. The model fit proved good, especially for the pilot filtration unit data. In conclusion, this model formulation is of the right level of complexity to be used for most practical MBR situations. PMID:24958618

  6. Performance of a membrane bioreactor used for the treatment of wastewater contaminated with heavy metals.

    PubMed

    Katsou, Evina; Malamis, Simos; Loizidou, Maria

    2011-03-01

    In this work the performance of a Membrane bioreactor (MBR) was assessed for the removal of 3-15 mg/l of copper, lead, nickel and zinc from wastewater. The average removal efficiencies accomplished by the MBR system were 80% for Cu(II), 98% for Pb(II), 50% for Ni(II) and 77% for Zn(II). The addition of 5 g/l vermiculite into the biological reactor enhanced metal removal to 88% for copper, 85% for zinc and 60% for nickel due to adsorption of metal ions on the mineral, while it reduced biomass inhibition and increased biomass growth. The metal ions remaining in soluble form penetrated into the permeate, while those attached to sludge flocs were effectively retained by the ultrafiltration membranes. The average heterotrophic biomass inhibition was 50%, while it reduced to 29% when lower metal concentrations were fed into the reactor in the presence of vermiculite. The respective autotrophic biomass inhibition was 70% and 36%. The presence of heavy metals and vermiculite in the mixed liquor adversely impacted on membrane fouling.

  7. Fungal Quorum Quenching: A Paradigm Shift for Energy Savings in Membrane Bioreactor (MBR) for Wastewater Treatment.

    PubMed

    Lee, Kibaek; Lee, Seonki; Lee, Sang Hyun; Kim, Sang-Ryoung; Oh, Hyun-Suk; Park, Pyung-Kyu; Choo, Kwang-Ho; Kim, Yea-Won; Lee, Jung-Kee; Lee, Chung-Hak

    2016-10-18

    In the last 30 years, the use of membrane bioreactors (MBRs) for advanced wastewater treatment and reuse have been expanded continuously, but they still suffer from excessive energy consumption resulting from the intrinsic problem of membrane biofouling. One of the major causes of biofouling in MBRs is bacterial quorum sensing (QS) via N-acylhomoserine lactones (AHLs) and/or autoinducer-2 (AI-2), enabling intra- and interspecies communications, respectively. In this study, we demonstrate that farnesol can substantially mitigate membrane biofouling in a MBR due to its quorum quenching (QQ) activity. When Candida albicans (a farnesol producing fungus) entrapping polymer beads (AEBs) were placed in the MBR, the rate of transmembrane pressure (TMP) rise-up was substantially decreased, even for lower aeration intensities. This finding corresponds to a specific aeration energy savings of approximately 40% (25% through the physical washing effect and a further 15% through the biological QQ effect of AEBs) compared to conventional MBRs without AEBs. A real-time RT-qPCR analysis revealed that farnesol secreted from C. albicans mitigated the biofilm formation in MBRs via the suppression of AI-2 QS. Successful control of biofouling and energy savings through fungal-to-bacterial QQ could be expanded to the plant scale for MBRs in wastewater treatment with economic feasibility.

  8. Development and testing of a fully adaptable membrane bioreactor fouling model for a sidestream configuration system.

    PubMed

    Paul, Parneet

    2013-04-24

    A dead-end filtration model that includes the three main fouling mechanisms mentioned in Hermia (i.e., cake build-up, complete pore blocking, and pore constriction) and that was based on a constant trans-membrane pressure (TMP) operation was extensively modified so it could be used for a sidestream configuration membrane bioreactor (MBR) situation. Modifications and add-ons to this basic model included: alteration so that it could be used for varying flux and varying TMP operations; inclusion of a backwash mode; it described pore constriction (i.e., irreversible fouling) in relation to the concentration of soluble microbial products (SMP) in the liquor; and, it could be used in a cross flow scenario by the addition of scouring terms in the model formulation. The additional terms in this modified model were checked against an already published model to see if they made sense, physically speaking. Next this modified model was calibrated and validated in Matlab© using data collected by carrying out flux stepping tests on both a pilot sidestream MBR plant, and then a pilot membrane filtration unit. The model fit proved good, especially for the pilot filtration unit data. In conclusion, this model formulation is of the right level of complexity to be used for most practical MBR situations.

  9. Co-Utilization of Glucose and Xylose for Enhanced Lignocellulosic Ethanol Production with Reverse Membrane Bioreactors

    PubMed Central

    Ishola, Mofoluwake M.; Ylitervo, Päivi; Taherzadeh, Mohammad J.

    2015-01-01

    Integrated permeate channel (IPC) flat sheet membranes were examined for use as a reverse membrane bioreactor (rMBR) for lignocellulosic ethanol production. The fermenting organism, Saccharomyces cerevisiae (T0936), a genetically-modified strain with the ability to ferment xylose, was used inside the rMBR. The rMBR was evaluated for simultaneous glucose and xylose utilization as well as in situ detoxification of furfural and hydroxylmethyl furfural (HMF). The synthetic medium was investigated, after which the pretreated wheat straw was used as a xylose-rich lignocellulosic substrate. The IPC membrane panels were successfully used as the rMBR during the batch fermentations, which lasted for up to eight days without fouling. With the rMBR, complete glucose and xylose utilization, resulting in 86% of the theoretical ethanol yield, was observed with the synthetic medium. Its application with the pretreated wheat straw resulted in complete glucose consumption and 87% xylose utilization; a final ethanol concentration of 30.3 g/L was obtained, which corresponds to 83% of the theoretical yield. Moreover, complete in situ detoxification of furfural and HMF was obtained within 36 h and 60 h, respectively, with the rMBR. The use of the rMBR is a promising technology for large-scale lignocellulosic ethanol production, since it facilitates the co-utilization of glucose and xylose; moreover, the technology would also allow the reuse of the yeast for several batches. PMID:26633530

  10. Dynamics of the Fouling Layer Microbial Community in a Membrane Bioreactor

    PubMed Central

    Ziegler, Anja S.; McIlroy, Simon J.; Larsen, Poul; Albertsen, Mads; Hansen, Aviaja A.; Heinen, Nicolas; Nielsen, Per Halkjær

    2016-01-01

    Membrane fouling presents the greatest challenge to the application of membrane bioreactor (MBR) technology. Formation of biofilms on the membrane surface is the suggested cause, yet little is known of the composition or dynamics of the microbial community responsible. To gain an insight into this important question, we applied 16S rRNA gene amplicon sequencing with a curated taxonomy and fluorescent in situ hybridization to monitor the community of a pilot-scale MBR carrying out enhanced biological nitrogen and phosphorus removal with municipal wastewater. In order to track the dynamics of the fouling process, we concurrently investigated the communities of the biofilm, MBR bulk sludge, and the conventional activated sludge system used to seed the MBR system over several weeks from start-up. As the biofilm matured the initially abundant betaproteobacterial genera Limnohabitans, Hydrogenophaga and Malikia were succeeded by filamentous Chloroflexi and Gordonia as the abundant species. This study indicates that, although putative pioneer species appear, the biofilm became increasingly similar to the bulk community with time. This suggests that the microbial population in bulk water will largely determine the community structure of the mature biofilm. PMID:27399199

  11. Biological nitrogen and phosphorus removal in membrane bioreactors: model development and parameter estimation.

    PubMed

    Cosenza, Alida; Mannina, Giorgio; Neumann, Marc B; Viviani, Gaspare; Vanrolleghem, Peter A

    2013-04-01

    Membrane bioreactors (MBR) are being increasingly used for wastewater treatment. Mathematical modeling of MBR systems plays a key role in order to better explain their characteristics. Several MBR models have been presented in the literature focusing on different aspects: biological models, models which include soluble microbial products (SMP), physical models able to describe the membrane fouling and integrated models which couple the SMP models with the physical models. However, only a few integrated models have been developed which take into account the relationships between membrane fouling and biological processes. With respect to biological phosphorus removal in MBR systems, due to the complexity of the process, practical use of the models is still limited. There is a vast knowledge (and consequently vast amount of data) on nutrient removal for conventional-activated sludge systems but only limited information on phosphorus removal for MBRs. Calibration of these complex integrated models still remains the main bottleneck to their employment. The paper presents an integrated mathematical model able to simultaneously describe biological phosphorus removal, SMP formation/degradation and physical processes which also include the removal of organic matter. The model has been calibrated with data collected in a UCT-MBR pilot plant, located at the Palermo wastewater treatment plant, applying a modified version of a recently developed calibration protocol. The calibrated model provides acceptable correspondence with experimental data and can be considered a useful tool for MBR design and operation.

  12. Filterability assessment in membrane bioreactors using an in-situ filtration test cell.

    PubMed

    de la Torre, Teresa; Mottschall, Moritz; Lesjean, Boris; Drews, Anja; Iheanaetu, Andrew; Kraume, Matthias

    2010-01-01

    A new method for the assessment of the filterability in membrane bioreactors was tested for five months in four MBR units in Berlin. The new method BFM (Berlin Filtration Method) for filterability assessment uses a small membrane filtration test cell which can be submerged directly in the biological tanks to determine the filterability of the activated sludge in-situ. The test cell contains an aerated flat-sheet membrane which operates at similar conditions as in the plant. Filterability is expressed in terms of critical flux obtained by performing flux-stepping experiments. The ultimate goal of monitoring the filterability with the device is to detect in real time fouling occurrences due to changes in sludge composition and to adapt accordingly the operating conditions. The usefulness of the device for this purpose was evaluated for five months after monitoring four MBR plants in Berlin with different activated sludge characteristics (MLSS from 5 to 21 g/L, SRT 12-35 d and COD in the supernatant 30-400 mg/L). The first results show a good agreement between the filterability of the sludge with the portable filtration test cell and the filtration performance of the plant. Critical flux values varied between 3 and 30 L/m(2) h during the studied period. Useful information concerning the irreversibility of the fouling was provided by looking at the hysteresis curve of the flux-stepping experiments.

  13. Mechanism of charged pollutants removal in an ion exchange membrane bioreactor: drinking water denitrification.

    PubMed

    Velizarov, S; Rodrigues, C M; Reis, M A; Crespo, J G

    The mechanism of anionic pollutant removal in an ion exchange membrane bioreactor (IEMB) was studied for drinking water denitrification. This hybrid process combines continuous ion exchange transport (Donnan dialysis) of nitrate and its simultaneous bioreduction to gaseous nitrogen. A nonporous mono-anion permselective membrane precludes direct contact between the polluted water and the denitrifying culture and prevents secondary pollution of the treated water with dissolved nutrients and metabolic products. Complete denitrification may be achieved without accumulation of NO3(-) and NO2(-) ions in the biocompartment. Focus was given to the effect of the concentration of co-ions, counterions, and ethanol on the IEMB performance. The nitrate overall mass transfer coefficient in this hybrid process was found to be 2.8 times higher compared to that in a pure Donnan dialysis process without denitrification. Furthermore, by adjusting the ratio of co-ions between the biocompartment and the polluted water compartment, the magnitude and direction of each individual anion flux can be easily regulated, allowing for flexible process operation and control. Synthetic groundwater containing 135-350 mg NO3(-) L(-1) was treated in the IEMB system. A surface denitrification rate of 33 g NO3(-) per square meter of membrane per day was obtained at a nitrate loading rate of 360 g NO3(-) m(-3)d(-1), resulting in a nitrate removal efficiency of 85%.

  14. Start-up of two moving bed membrane bioreactors treating saline wastewater contaminated by hydrocarbons.

    PubMed

    Campo, R; Di Prima, N; Freni, G; Giustra, M G; Di Bella, G

    2016-01-01

    This work aims to assess the acclimation of microorganisms to a gradual increase of salinity and hydrocarbons, during the start-up of two moving bed membrane bioreactors (MB-MBRs) fed with saline oily wastewater. In both systems an ultrafiltration membrane was used and two types of carriers were employed: polyurethane sponge cubes (MB-MBRI) and polyethylene cylindrical carriers (MB-MBRII). A decreasing dilution factor of slops has been adopted in order to allow biomass acclimation. The simultaneous effect of salinity and hydrocarbons played an inhibitory role in biomass growth and this resulted in a decrease of the biological removal efficiencies. A reduction of bound extracellular polymeric substances and a simultaneous release of soluble microbial products (SMPs) were observed, particularly in the MB-MBRII system, probably due to the occurrence of a greater suspended biomass stress as response to the recalcitrance of substrate. On the one hand, a clear attachment of biomass occurred only in MB-MBRI and this affected the fouling deposition on the membrane surface. The processes of detachment and entrapment of biomass, from and into the carriers, significantly influenced the superficial cake deposition and its reversibility. On the other hand, in MB-MBRII, the higher production of SMPs implied a predominance of the pore blocking.

  15. Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

    PubMed

    Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-02-01

    There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties.

  16. The application of nitric oxide to control biofouling of membrane bioreactors

    PubMed Central

    Luo, Jinxue; Zhang, Jinsong; Barnes, Robert J; Tan, Xiaohui; McDougald, Diane; Fane, Anthony G; Zhuang, Guoqiang; Kjelleberg, Staffan; Cohen, Yehuda; Rice, Scott A

    2015-01-01

    A novel strategy to control membrane bioreactor (MBR) biofouling using the nitric oxide (NO) donor compound PROLI NONOate was examined. When the biofilm was pre-established on membranes at transmembrane pressure (TMP) of 88–90 kPa, backwashing of the membrane module with 80 μM PROLI NONOate for 45 min once daily for 37 days reduced the fouling resistance (Rf) by 56%. Similarly, a daily, 1 h exposure of the membrane to 80 μM PROLI NONOate from the commencement of MBR operation for 85 days resulted in reduction of the TMP and Rf by 32.3% and 28.2%. The microbial community in the control MBR was observed to change from days 71 to 85, which correlates with the rapid TMP increase. Interestingly, NO-treated biofilms at 85 days had a higher similarity with the control biofilms at 71 days relative to the control biofilms at 85 days, indicating that the NO treatment delayed the development of biofilm bacterial community. Despite this difference, sequence analysis indicated that NO treatment did not result in a significant shift in the dominant fouling species. Confocal microscopy revealed that the biomass of biopolymers and microorganisms in biofilms were all reduced on the PROLI NONOate-treated membranes, where there were reductions of 37.7% for proteins and 66.7% for microbial cells, which correlates with the reduction in TMP. These results suggest that NO treatment could be a promising strategy to control biofouling in MBRs. PMID:25752591

  17. PRACTICE REVIEW OF FIVE BIOREACTOR/RECIRCULATION LANDFILLS

    EPA Science Inventory

    Six bioreactor landfills were analyzed to provide a perspective of current practice and technical issues that differentiate bioreactor landfills from conventional landfills. Five of the bioreactor landfills were anaerobic and one was aerated. In one case, nearly identical cells e...

  18. Targeted modification of organic components of municipal solid waste by short-term pre-aeration and its enhancement on anaerobic degradation in simulated landfill bioreactors.

    PubMed

    Ni, Zhe; Liu, Jianguo; Girotto, Francesca; Cossu, Raffaello; Qi, Guangxia

    2016-09-01

    Pre-aeration is effective on regulating subsequent anaerobic degradation of municipal solid waste (MSW) with high organic fractions during landfilling. The strength of pre-aeration should be optimized to intentionally remove some easily biodegradable fractions while conserve bio-methane potential as much as possible. This study investigates the evolution of organic components in MSW during 2-14days pre-aeration process and its impacts on subsequent anaerobic degradation in simulated landfill bioreactors. Results showed that a 6-day pre-aeration enabled to develop a thermophilic stage, which significantly accelerated biodegradation of organics except lignocelluloses, with removal rates of 42.8%, 76.7% and 25.1% for proteins, carbohydrates and lipids, respectively. Particularly, ammonia from accelerated ammonification in the thermophilic stage neutralized VFAs generated from anaerobic landfilling. As a result, the MSW with 6-day pre-aeration obtained the highest methane yield 123.4NL/kg dry matter. Therefore, it is recommended to interrupt pre-aeration before its cooling stage to switch to anaerobic landfilling.

  19. Detection of microbial communities in continuous and discontinuous membrane bioreactor using high-density oligonucleotide Microarray

    NASA Astrophysics Data System (ADS)

    Duan, Liang; Song, Yonghui; Xia, Siqing; Hermanowicz, Slawomir W.

    2010-11-01

    This study compared the whole composition of microbial communities in continuous-flow (MBR) and batch-fed (discontinuous) (MSBR) aerobic membrane bioreactors using high-density universal 16S rRNA Microarray. The array includes 506,944 probes targeted to 8935 clusters in 16S rRNA gene sequences. The Microarray results showed that both MBR and MSBR had high microbial diversity. 1126 and 1002 bacterial subfamilies were detected and can separate as 37 and 32 phyla in MBR and MSBR, respectively. Proteobacteria was the predominant phylum, 703 and 597 subfamilies were found in two systems, which constituted 62.4% and 59.6% of the whole bacteria. Gamma- and Alpha-were the dominant classes in Proteobacteria. It occupied 38.1% and 26.3%, 31.2% and 39.2% for MBR and MSBR, respectively. Bacteroidetes, Firmicutes and Actinobacteria were the subdominant groups, occupying around 9.4% and 7.6%, 6.1% and 6.5%, 6.0% and 9.0% of the total bacteria in two reactors. Some bacterial groups such as Acidobacteria, Chloroflexi, Cyanobacteria, Verrucomicrobia and Spirochaetes also found more than 15 subfamilies. All the results indicated that the MBR system had more bacteria community diversity than MSBR's. Moreover, it was very interested that MBR and MSBR had almost the same bacterial composition except Enterobacteriaceae. 63 OTUs of Enterobacteriaceae were detected in MBR, while just 10 OTUs were found in MSBR. That's one of the reasons leading to the difference of the bacterial diversity between two bioreactors.

  20. Comparative 16S rRNA gene surveys of granular sludge from three upflow anaerobic bioreactors treating purified terephthalic acid (PTA) wastewater.

    PubMed

    Perkins, S D; Scalfone, N B; Angenent, L T

    2011-01-01

    The microbial communities from three upflow anaerobic bioreactors treating purified terephthalic acid (PTA) wastewater were characterized with 16S ribosomal RNA gene sequencing surveys. Universal bacterial and archaeal primers were used to compare the bioreactor communities to each other. A total of 1,733 bacterial sequences and 383 archaeal sequences were characterized. The high number of Syntrophus spp. and Pelotomaculum spp. found within these reactors indicates efficient removal of benzoate and terephthalate. Under anaerobic conditions benzoate can be degraded through syntrophic associations between these bacteria and hydrogen-scavenging microbes, such as Desulfovibrio spp. and hydrogenotrophic methanogens, which remove H(2) to force the thermodynamically unfavourable reactions to take place. The authors did not observe a relatively high percentage of hydrogenotrophic methanogens with the archaeal gene survey because of a high acetate flux (acetate is a main component in PTA wastewater and is the main degradation product of terephthalate/benzoate fermentation), and because of the presence of Desulfovibrio spp. (a sulfate reducer that scavenges hydrogen). The high acetate flux also explains the high percentage of acetoclastic methanogens from the genus Methanosaeta among the archaeal sequences. A group of uncultured bacteria (OD1) may be involved in the degradation of p-toluate (4-methyl benzoate), which is a component of PTA wastewater.

  1. Removal of bromate from drinking water using the ion exchange membrane bioreactor concept.

    PubMed

    Matos, Cristina T; Velizarov, Svetlozar; Reis, Maria A M; Crespo, João G

    2008-10-15

    Bromate is a disinfection byproduct with carcinogenic properties that has to be removed from drinking water to concentrations below 10 or 25 microg/L. This work evaluates the applicability of the ion exchange membrane bioreactor (IEMB) concept for the removal of bromate from drinking water, in situations where nitrate is also present in concentrations up to 3 orders of magnitude higher than bromate. The batch results obtained show that the biological reduction of bromate was slow and only occurring after the complete reduction of nitrate. The specific bromate reduction rates varied from 0.027 +/- 0.01 mg BrO3(-)/g(cell dry weight) x h to 0.090 mg BrO3(-)/ g(cell dry weight) x h for the studied concentrations. On the other hand, transport studies, using anion exchange membranes showed that Donnan dialysis could efficiently remove bromate from polluted waters. Therefore, the use of a dense, nonporous membrane in the IEMB system, isolates the water stream from the biological compartment, allowing for the uncoupling of the water production rate from the biological reduction rate. The IEMB system was used for the treatment of a polluted water stream containing 200 microg/L of BrO3(-) and 60 mg/L of NO3(-). The concentrations of both ions in the treated water were reduced below the recommended levels. No bromate accumulation was observed in the biocompartment of the IEMB, suggesting its complete reduction in the biofilm formed on the membrane surface contacting the biocompartment. Therefore, the IEMB has proven to be a technology able to solve specific problems associated with the removal of bromate from water streams, since it efficiently removes bromate from drinking water even in the presence of nitrate, a known competitor of bromate biological reduction, without secondary contamination of the treated water by cells or excess of carbon source.

  2. Immersed membrane bioreactor (IMBR) for treatment of combined domestic and dairy wastewater in an isolated farm.

    PubMed

    Bick, A; Tuttle, J G P; Shandalov, S; Oron, G

    2005-01-01

    In many regions dairy farms and milk processing industries discharge large quantities of their wastes to the surroundings posing serious environmental risks. This problem is mostly faced in small dairy farms and isolated communities lacking both central collection and conventional wastewater treatment systems. Dairy wastewater is characterized by high concentrations of organic matter, solids, nutrients, as well as fractions of dissolved inorganic pollutants, exceeding those levels considered typical for high strength domestic wastewaters. With the purpose of treating the combined dairy and domestic wastewater from a small dairy farm in the Negev Desert of Israel, the use of a recent emerging technology of Immersed Membrane BioReactor (IMBR) was evaluated over the course of 500 test hours, under a variety of wastewater feed quality conditions (during the test periods, the feed BOD5 ranged from 315 ppm up to 4,170 ppm). The overall performance of a pilot-scale Ultrafiltration (UF) IMBR process for a combined domestic and dairy wastewater was analyzed based on the Data Envelopment Analysis (DEA) method. The IMBR performance in terms of membrane performance (permeate flux, transmembrane pressure, and organic removal) and DEA model (Technical Efficiency) was acceptable. DEA is an empirically based methodology and the research approach has been found to be effective in the depiction and analysis for complex systems, where a large number of mutual interacting variables are involved.

  3. Demonstration of efficient trichloroethylene biodegradation in a hollow-fiber membrane bioreactor

    SciTech Connect

    Pressman, J.G.; Georgiou, G.; Speitel, G.E. Jr.

    1999-03-20

    Rapid cometabolism of trichloroethylene (TCE) by pure cultures of Methylosinus trichosporium OB3b PP358 was demonstrated in a two-stage hollow-fiber membrane bioreactor over the course of 3 weeks. PP358 was grown in a continuous-flow chemostat and circulated through the shell of a hollow-fiber membrane module (HFMM), while TCE contaminated water was pumped through the fiber lumen. In parallel-flow HFMM biological experiments, 82% to 89% of the influent TCE was removed from the lumen with 99% of the transferred TCE undergoing biodegradation. Biological experiments in a larger capacity baffled radial-flow HFMM resulted in 66% to 99% TCE transferred and 93% to 96% TCE biodegradation at lumen residence times of between 1.5 and 3.7 min. Biodegradation was maintained throughout the experiments at pseudo-first-order biodegradation rate constants of 0.41 to 2.8 L/mg TSS/day. Best-fit computer modeling of the baffled radial-flow biological process estimated mass transfer coefficients as large as 2.7 {times} 10{sup {minus}2} cm/min. The computer model was also shown to simulate the experimental results quite well.

  4. Validation of computational non-Newtonian fluid model for membrane bioreactor.

    PubMed

    Sørensen, Lasse; Bentzen, Thomas Ruby; Skov, Kristian

    2015-01-01

    Membrane bioreactor (MBR) systems are often considered as the wastewater treatment method of the future due to their high effluent quality. One of the main problems with such systems is a relative large energy consumption, compared to conventional activated sludge (CAS) systems, which has led to further research in this specific area. A powerful tool for optimizing MBR-systems is computational fluid dynamics (CFD) modelling, which gives researchers the ability to describe the flow in the systems. A parameter which is often neglected in such models is the non-Newtonian properties of active sludge, which is of great importance for MBR systems since they operate at sludge concentrations up to a factor of 10 compared to CAS systems, resulting in strongly shear thinning liquids. A CFD-model is validated against measurements conducted in a system with rotating cross-flow membranes submerged in non-Newtonian liquids, where tangential velocities are measured with a Laser Doppler Anemometer (LDA). The CFD model is found to be capable of modelling the correct velocities in a range of setups, making CFD models a powerful tool for optimization of MBR systems.

  5. Considerations on the design and financial feasibility of full-scale membrane bioreactors for municipal applications.

    PubMed

    Brepols, Ch; Schäfer, H; Engelhardt, N

    2010-01-01

    Based on the practical experience in design and operation of three full-scale membrane bioreactors (MBR) for municipal wastewater treatment that were commissioned since 1999, an overview on the different design concepts that were applied to the three MBR plants is given. The investment costs and the energy consumption of the MBRs and conventional activated sludge (CAS) plants (with and without tertiary treatment) in the Erft river region are compared. It is found that the specific investment costs of the MBR plants are lower than those of comparable CAS with tertiary treatment. A comparison of the specific energy demand of MBRs and conventional WWTPs is given. The structure of the MBRs actual operational costs is analysed. It can be seen that energy consumption is only responsible for one quarter to one third of all operational expenses. Based on a rough design and empirical cost data, a cost comparison of a full-scale MBR and a CAS is carried out. In this example the CAS employs a sand filtration and a disinfection in order to achieve comparable effluent quality. The influence of membrane lifetime on life cycle cost is assessed.

  6. Membrane bioreactor application within the treatment of high-strength textile effluent.

    PubMed

    De Jager, D; Sheldon, M S; Edwards, W

    2012-01-01

    A pilot-scale dual-stage membrane bioreactor (dsMBR) incorporating two ultra-filtration (UF) side-stream membrane modules was designed, constructed, operated and evaluated on-site for treating high-strength textile effluent. The effluent stream was characterised by a COD range of between 45 to 2,820 mg/L and an average BOD of 192.5 mg/L. The dsMBR achieved an average COD reduction of 75% with a maximum of 97% over the 9 month test period. The COD concentration obtained after dsMBR treatment averaged at 190 mg/L, which was well within the discharge standard. The average reduction in turbidity and TSS were 94% and 19.6%, respectively, during the UF-MBR stage of the system. Subsequent treatment of the UF-permeate with nanofiltration (NF) and reverse osmosis (RO) removed both the residual colour and remaining salt. A consistent reduction in the color of the incoming effluent was evident. The ADMI was reduced from an average of 659 to ∼20, a lower ADMI and colour compared to the potable water. An average conductivity rejection of 91% was achieved with conductivity being reduced from an average of 7,700 to 693 μS/cm and the TDS reduced from an average of 5,700 to 473 mg/L, which facilitated an average TDS rejection of 92%.

  7. Aerobic biological treatment of synthetic municipal wastewater in membrane-coupled bioreactors.

    PubMed

    Klatt, Christian G; LaPara, Timothy M

    2003-05-05

    Membrane-coupled bioreactors (MBRs) offer many benefits compared to conventional biological wastewater treatment systems; however, their performance characteristics are poorly understood. Laboratory-scale MBRs were used to study bacterial adaptations in physiology and community structure. MBRs were fed a mixture of starch, gelatin, and polyoxyethylene-sorbitan monooleate to simulate the polysaccharide, protein, and lipid components of municipal wastewater. Physiological adaptations were detected by measuring ectoenzyme activity while structural dynamics were studied by denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments. As cell biomass accumulated in the MBRs, pollutant removal efficiency initially improved and then stabilized with respect to effluent concentrations of chemical oxygen demand, protein, and carbohydrate. Comparison of the MBR effluent to filtered reactor fluid indicated that a portion of the observed pollutant removal was due to filtration by the membrane rather than microbial activity. The rates of ectoenzyme-mediated polysaccharide (alpha-glucosidase) and protein (leucine aminopeptidase) hydrolysis became relatively constant once pollutant removal efficiency stabilized. However, the maximum rate of lipid hydrolysis (heptanoate esterase) concomitantly increased more than 10-fold. Similarly, alpha-glucosidase and leucine aminopeptidase ectoenzyme affinities were relatively constant, while the heptanoate esterase affinity increased more than 30-fold. Community analysis revealed that a substantial community shift occurred within the first 7 days of operation. A Flavobacterium-like bacterial population dominated the community (>50% of total band intensity) and continued to do so for the remainder of the experiment.

  8. Ten years of industrial and municipal membrane bioreactor (MBR) systems - lessons from the field.

    PubMed

    Larrea, Asun; Rambor, Andre; Fabiyi, Malcolm

    2014-01-01

    The use of membrane bioreactors (MBRs) in activated sludge wastewater treatment has grown significantly in the last decade. While there is growing awareness and knowledge about the application of MBR technology in municipal wastewater treatment, not much information is available on the application of MBRs in industrial wastewater treatment. A comparative study of design data, operating conditions and the major challenges associated with MBR operations in 24 MBR plants treating both municipal and industrial wastewater, built by and/or operated by Praxair, Inc., is presented. Of the 24 MBR systems described, 12 of the plants used high purity oxygen (HPO). By enabling a wide range of food/microorganism ratios and loading conditions in the same system, HPO MBR systems can extend the options available to industrial plant operators to meet the challenges of wide fluctuations in organic loading and footprint limitations. While fouling in industrial MBR systems can be an issue, adequate flux and permeability values can be reliably maintained by the use of good maintenance strategies and effective process controls (pretreatment, cleaning and membrane autopsies).

  9. Impact of bio-augmentation with Sphingomonas sp. strain TTNP3 in membrane bioreactors degrading nonylphenol.

    PubMed

    Cirja, Magdalena; Hommes, Gregor; Ivashechkin, Pavel; Prell, Jürgen; Schäffer, Andreas; Corvini, Philippe F X; Lenz, Markus

    2009-08-01

    This study evaluates the potential of bio-augmentation to improve the degradation of recalcitrant nonylphenol during the wastewater treatment in membrane bioreactors (MBR). One MBR containing activated sludge was bio-augmented using multistep inoculation with freeze dried Sphingomonas sp. strain TTNP3, whereas a second control reactor contained activated sludge solely. The (14)C-labeled-nonylphenol isomer (4-[1-ethyl-1,3-dimethylpentyl]phenol) was applied as a single pulse. Bio-augmentation resulted in an immediate increase of dissolved radioactivity in the effluent in comparison to the control reactor (13% and 2% of initially applied radioactivity after 1 day, respectively). After 5 days of operation, the retentate of the bio-augmented reactor contained only 7% of the initial radioactivity in contrast to 50% in the control reactor. The radioactivity associated to the mixed liquor suspended solids, i.e., the suspension of biomass and other solids on the retentate side of the membrane, was mainly found as non-extractable residues that were increasingly formed during prolonged reactor operation, especially for the control MBR. HPLC-LSC and GC-MS(n) analyses revealed that the bio-augmented reactor produced more polar hydroquinone as main degradation intermediate, whereas the control reactor effluent contained a complex mixture of apolar compounds with shortened oxidized alkyl chains. Thus, the apparent differences in the behavior of nonylphenol between the reactors were due to the catabolism of nonylphenol conferred by bio-augmentation with Sphingomonas sp. strain TTNP3.

  10. Removal of typical endocrine disrupting chemicals by membrane bioreactor: in comparison with sequencing batch reactor.

    PubMed

    Zhou, Yingjun; Huang, Xia; Zhou, Haidong; Chen, Jianhua; Xue, Wenchao

    2011-01-01

    The removal of endocrine disrupting chemicals (EDCs) by a laboratory-scale membrane bioreactor (MBR) fed with synthetic sewage was evaluated and moreover, compared with that by a sequencing batch reactor (SBR) operated under same conditions in parallel. Eight kinds of typical EDCs, including 17β-estradiol (E2), estrone (E1), estriol (E3), 17α-ethynilestradiol (EE2), 4-octylphenol (4-OP), 4-nonylphenol (4-NP), bisphenol A (BPA) and nonylphenol ethoxylates (NPnEO), were spiked into the feed. Their concentrations in influent, effluent and supernatant were determined by gas chromatography-mass spectrometry method. The overall estrogenecity was evaluated as 17β-estradiol equivalent quantity (EEQ), determined via yeast estrogen screen (YES) assay. E2, E3, BPA and 4-OP were well removed by both MBR and SBR, with removal rates more than 95% and no significant differences between the two reactors. However, with regard to the other four EDCs, of which the removal rates were lower, MBR performed better. Comparison between supernatant and effluent of the two reactors indicated that membrane separation of sludge and effluent, compared with sedimentation, can relatively improve elimination of target EDCs and total estrogenecity. By applying different solids retention times (SRTs) (5, 10, 20 and 40 d) to the MBR, 10 and 5 d were found to be the lower critical SRTs for efficient target EDCs and EEQ removal, respectively.

  11. Comparison of mixed liquor filterability measured with bench and pilot-scale membrane bioreactors.

    PubMed

    Nywening, J P; Zhou, H; Husain, H

    2007-01-01

    Parallel experimental tests to measure mixed liquor filterability for submerged membrane bioreactors were conducted over a six month period using three ZW-500 pilot plants and a ZW-10 lab-scale filterability apparatus. Non-air sparged conditions during the tests yielded operation behaviour that was equivalent to dead-end filtration. The fouling resistance increased linearly with the intercepted mass until a critical point was reached at which point significant cake compression was induced and the resistance began to increase exponentially. Although the point of cake compression appears to be dependent on the membrane module design, similar resistance per unit solid mass intercepted per unit area (R(mass)) values were observed when the same mixed liquor was filtered. Coupled with the established correlation between the R(mass) and the critical flux, it is suggested that the filterability test results from a side-stream, lab-scale module may be used to predict fouling potential in a full scale MBR wastewater treatment system without interrupting the full-scale MBR operation.

  12. Simultaneous removal of perchlorate and nitrate from drinking water using the ion exchange membrane bioreactor concept.

    PubMed

    Matos, Cristina T; Velizarov, Svetlozar; Crespo, João G; Reis, Maria A M

    2006-01-01

    This work evaluates the feasibility of the ion exchange membrane bioreactor (IEMB) concept for the simultaneous removal of perchlorate and nitrate from drinking water, when nitrate is present in the ppm range and perchlorate in the ppb range. The IEMB concept combines Donnan dialysis and simultaneous biological degradation of both pollutants. Membrane transport studies showed that Donnan dialysis is suitable for obtaining water with concentrations of perchlorate and nitrate below the recommended levels. However, the pollutants were accumulated in a receiving stream, thus requiring additional treatment before disposal. On the other hand, the IEMB process operated with hydraulic retention times ranging from 1.4 to 8.3h in the water compartment, proved to remove effectively perchlorate and nitrate while preserving the water composition with respect to other ions, thus avoiding secondary contamination of the treated water. For a polluted water stream containing 100 ppb of ClO(4)(-) and 60 ppm of NO(3)(-), the concentrations of both ions in the treated stream were kept below the recommended levels of 4 ppb for ClO(4)(-) and 25 ppm for NO(3)(-). The IEMB system was operated under ethanol limitation, but even under these conditions, an increase of the perchlorate and nitrate concentrations in the treated water was not observed for up to 6 days.

  13. Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity.

    PubMed

    Mannina, Giorgio; Capodici, Marco; Cosenza, Alida; Di Trapani, Daniele; Viviani, Gaspare

    2016-06-01

    In this work, a sequential batch membrane bioreactor pilot plant is investigated to analyze the effect of a gradual increase in salinity on carbon and nutrient removal, membrane fouling and biomass kinetic parameters. The salinity was increased by 2gNaClL(-1) per week up to 10gNaClL(-1). The total COD removal efficiency was quite high (93%) throughout the experiment. A gradual biomass acclimation to the salinity level was observed during the experiment, highlighting the good recovery capabilities of the system. Nitrification was also influenced by the increase in salinity, with a slight decrease in nitrification efficiency (the lowest value was obtained at 10gNaClL(-1) due to lower nitrifier activity). Irreversible cake deposition was the predominant fouling mechanism observed during the experiment. Respirometric tests exhibited a stress effect due to salinity, with a reduction in the respiration rates observed (from 8.85mgO2L(-1)h(-1) to 4mgO2L(-1)h(-1)).

  14. Mathematical modeling of continuous ethanol fermentation in a membrane bioreactor by pervaporation compared to conventional system: Genetic algorithm.

    PubMed

    Esfahanian, Mehri; Shokuhi Rad, Ali; Khoshhal, Saeed; Najafpour, Ghasem; Asghari, Behnam

    2016-07-01

    In this paper, genetic algorithm was used to investigate mathematical modeling of ethanol fermentation in a continuous conventional bioreactor (CCBR) and a continuous membrane bioreactor (CMBR) by ethanol permselective polydimethylsiloxane (PDMS) membrane. A lab scale CMBR with medium glucose concentration of 100gL(-1) and Saccharomyces cerevisiae microorganism was designed and fabricated. At dilution rate of 0.14h(-1), maximum specific cell growth rate and productivity of 0.27h(-1) and 6.49gL(-1)h(-1) were respectively found in CMBR. However, at very high dilution rate, the performance of CMBR was quite similar to conventional fermentation on account of insufficient incubation time. In both systems, genetic algorithm modeling of cell growth, ethanol production and glucose concentration were conducted based on Monod and Moser kinetic models during each retention time at unsteady condition. The results showed that Moser kinetic model was more satisfactory and desirable than Monod model.

  15. Osmotic membrane bioreactor for wastewater treatment and the effect of salt accumulation on system performance and microbial community dynamics.

    PubMed

    Qiu, Guanglei; Ting, Yen-Peng

    2013-12-01

    An osmotic membrane bioreactor was developed for wastewater treatment. The effects of salt accumulation on system performance and microbial community dynamics were investigated. Evident deterioration of biological activity, especially nitrification, was observed, which resulted in significant accumulation of organic matter and NH4(+)-N within the bioreactor. Arising from the elevation of salinity, almost all the dominant species was taken over by high salt-tolerant species. Significant succession among different species of Nitromonas was observed for ammonia-oxidizing bacteria. For nitrite-oxidizing bacteria, Nitrospira was not evidently affected, whereas Nitrobacter was eliminated from the system. Salt accumulation also caused significant shifts in denitrifying bacterial community from α- to γ-Proteobacteria members. Overall, the microbial community adapted to the elevated salinity conditions and brought about a rapid recovery of the biological activity. Membrane fouling occurred but was insignificant. Biofouling and inorganic scaling coexisted, with magnesium/calcium phosphate/carbonate compounds identified as the inorganic foulants.

  16. Numerical simulation of bubble induced shear in membrane bioreactors: effects of mixed liquor rheology and membrane configuration.

    PubMed

    Liu, Xuefei; Wang, Yuan; Waite, T David; Leslie, Greg

    2015-05-15

    A CFD model, incorporating an empirically determined rheology model and a porous media model, was developed to simulate bubble induced surface shear in membrane bioreactors configured with hollow fibre membranes with outer diameters ranging from 1.3 to 2.4 mm, arranged in vertically orientated modules with packing density from 200 to 560 m(2)/m(3). The rheology model was developed for mixed liquor suspended solids (MLSS) concentrations of 3 to 16 gL(-1) in the presence and absence of coagulant (generated by addition of a ferrous salt) for shear rates ranging from 0 to 500 s(-1). Experimentally determined particle relaxation times for the biological flocs in the mixed liquor, both in the absence and presence of iron, were negligible, consistent with an environment where positive buoyancy forces were greater than negative settling forces thereby allowing the sludge mixture to be modelled as a single continuous phase. The non-Newtonian behaviour of the mixed liquor was incorporated into the CFD simulations using an Ostwald-de Waele rheology model. Interactions between mixed liquor and hollow fibre membranes of different fibre size and packing density were described using a porous media model that was calibrated by empirical measurement of inertial loss coefficients over a range of viscosities (0.8 × 10(-3) to 2.1 × 10(-3) Pa.s) and velocities (0 to 0.35 m/s) typically encountered in full scale MBRs. Experimental results indicated that addition of iron salts resulted in an increase in MLSS and sludge viscosity. Shear stress is affected by both velocity and viscosity. The increase in sludge viscosity resulted in an increase in resistance to flow through the hollow fibre membrane bundles and, as a result, decreased the liquid flow velocities. CFD simulations provided insight on the effects of point of coagulant addition and MLSS concentration on bubble-induced shear over a range of industrially relevant conditions. A 12% increase in shear stress was observed when

  17. Removal properties of human enteric viruses in a pilot-scale membrane bioreactor (MBR) process.

    PubMed

    Miura, Takayuki; Okabe, Satoshi; Nakahara, Yoshihito; Sano, Daisuke

    2015-05-15

    In order to evaluate removal properties of human enteric viruses from wastewater by a membrane bioreactor (MBR), influent, anoxic and oxic mixed liquor, and membrane effluent samples were collected in a pilot-scale anoxic-oxic MBR process for 16 months, and concentrations of enteroviruses, norovirus GII, and sapoviruses were determined by real-time PCR using murine norovirus as a process control. Mixed liquor samples were separated into liquid and solid phases by centrifugation, and viruses in the bulk solution and those associated with mixed liquor suspended solids (MLSS) were quantified. Enteroviruses, norovirus GII, and sapoviruses were detected in the influent throughout the sampling period (geometrical mean, 4.0, 3.1, and 4.4 log copies/mL, respectively). Enterovirus concentrations in the solid phase of mixed liquor were generally lower than those in the liquid phase, and the mean log reduction value between influent and anoxic mixed liquor was 0.40 log units. In contrast, norovirus GII and sapovirus concentrations in the solid phase were equal to or higher than those in the liquid phase, and higher log reduction values (1.3 and 1.1 log units, respectively) were observed between influent and anoxic mixed liquor. This suggested that enteroviruses were less associated with MLSS than norovirus GII and sapoviruses, resulting in lower enterovirus removal in the activated sludge process. Enteroviruses and norovirus GII were detected in the MBR effluent but sapoviruses were not in any effluent samples. When MLSS concentration was reduced to 50-60% of a normal operation level, passages of enteroviruses and norovirus GII through a PVDF microfiltration membrane were observed. Since rejection of viruses by the membrane was not related to trans-membrane pressure which was monitored as a parameter of membrane fouling, the results indicated that adsorption to MLSS plays an important role in virus removal by an MBR, and removal properties vary by viruses reflecting different

  18. Fouling control in membrane bioreactors with sewage-sludge based adsorbents.

    PubMed

    Villamil, J A; Monsalvo, V M; Lopez, J; Mohedano, A F; Rodriguez, J J

    2016-11-15

    The potential application of powdered activated carbon (PAC) to mitigate membrane fouling has been tested in membrane bioreactors (MBRs) fed with cosmetic wastewater. Inexpensive powder activated carbon was prepared from sewage sludge biosolids (B-PAC) by pyrolysis (750 °C; 0.5 h) and air-activation (400 °C; 2 h). Adsorption capacities of 143 and 570 mg g(-1) were reached for carbohydrates and proteins, respectively, quite similar to those of a commercial activated carbon (C-PAC). To check the effect of PAC addition on membrane fouling, three MBRs were simultaneously operated without (control-MBR) and with PAC (B-MBR and C-MBR) for 150 days in continuous mode at 8 L m(-2) h(-1) flux. Similar COD removal efficiencies were achieved in these three MBR systems. After 100 days of operation, the effect of the PACs on the sludge filterability was studied in the MBRs for 10 days. B-MBR showed stable transmembrane pressure (TMP) after 9 days of operation, unlike of control-MBR and C-MBR, where the TMP increased after the 2nd and 5th days, respectively. Therefore, operational cost saving can be achieved in the membrane cleaning due to decrease of fouling rate. Operating at stable state condition the addition of PAC gave rise to an increase of the critical flux of 25%. In an extra shear test, carried out at the end of the continuous experiment, a clear reduction in mean size of the flocs from 45 to 28 μm was observed in control-MBR. However, the extra shear led to a slight reduction of the mean size of flocs (less than 5%) in MBRs with PAC, with average sizes of 62 and 71 μm in C-MBR and B-MBR, respectively. The molecular weight fractionation of the MBR demonstrated a higher selectivity of B-PAC toward the adsorption of proteins smaller than 1 μm which prevents the irreversible fouling of the membranes. The membranes lifetime was increased because the B-PAC extended the filtration for a longer period than C-PAC, probably due to its easier in-situ regeneration.

  19. Review on the state of science on membrane bioreactors for municipal wastewater treatment.

    PubMed

    van Nieuwenhuijzen, A F; Evenblij, H; Uijterlinde, C A; Schulting, F L

    2008-01-01

    Over the past two decades the field of application for membrane bioreactors has broadened towards the municipal wastewater treatment sector. The Global Water Research Coalition (GWRC) determined MBR technology to be of priority for collaborative research and decided to conduct a project with the aim to determine the current state of the science in the field of MBR for municipal wastewater treatment and to develop a phased research strategy represented by priority research projects, like a State of the Science report with regard to MBR technology. This paper describes the state of the science with regard to MBR technology for municipal wastewater treatment by 2007, derived by literature review on recent publications, database analysis and international questionnaires. The research efforts from the past seven years can be characterised by the following prioritised list: (1) membrane fouling, (2) effluent quality, (3) energy consumption (aeration) and (4) cost considerations. The research needs for the near future as identified with the questionnaire are comparable to the main topics of research as identified in the literature review: membrane fouling is still the main problem requiring thorough attention from scientists; effluent quality is a main driver for the application of the technology. There remain some important questions however, with regard to the removal of EDC and micro pollutants. Much of the research activities on MBR are repeated more than once by research groups world-wide. This is only partially caused by a lack of knowledge exchange between researchers. However, lacking information exchange between Europe and the USA on MBR research is identified as a potential bottleneck. Another point of attention is the fast that research results can not easily be translated to other (more practical) situations, since much of the research is carried out at pilot scale.

  20. Bacteriophage removal in a full-scale membrane bioreactor (MBR) - Implications for wastewater reuse.

    PubMed

    Purnell, Sarah; Ebdon, James; Buck, Austen; Tupper, Martyn; Taylor, Huw

    2015-04-15

    The aim of this study was to assess the potential removal efficacy of viruses in a full-scale membrane bioreactor (MBR) wastewater reuse system, using a range of indigenous and 'spiked' bacteriophages (phages) of known size and morphology. Samples were taken each week for three months from nine locations at each treatment stage of the water recycling plant (WRP) and tested for a range of microbiological parameters (n = 135). Mean levels of faecal coliforms were reduced to 0.3 CFU/100 ml in the MBR product and were undetected in samples taken after the chlorination stage. A relatively large reduction (5.3 log) in somatic coliphages was also observed following MBR treatment. However, F-specific and human-specific (GB124) phages were less abundant at all stages, and demonstrated log reductions post-MBR of 3.5 and 3.8, respectively. In 'spiking' experiments, suspended 'spiked' phages (MS2 and B-14) displayed post-MBR log reductions of 2.25 and 2.30, respectively. The removal of these suspended phages, which are smaller than the membrane pore size (0.04 μm), also highlights the possible role of the membrane biofilm as an effective additional barrier to virus transmission. The findings from this study of a full-scale MBR system demonstrate that the enumeration of several phage groups may offer a practical and conservative way of assessing the ability of MBR to remove enteric viruses of human health significance. They also suggest that phage removal in MBR systems may be highly variable and may be closely related on the one hand to both the size and morphology of the viruses and, on the other, to whether or not they are attached to solids.

  1. The environmental footprint of a membrane bioreactor treatment process through Life Cycle Analysis.

    PubMed

    Ioannou-Ttofa, L; Foteinis, S; Chatzisymeon, E; Fatta-Kassinos, D

    2016-10-15

    This study includes an environmental analysis of a membrane bioreactor (MBR), the objective being to quantitatively define the inventory of the resources consumed and estimate the emissions produced during its construction, operation and end-of-life deconstruction. The environmental analysis was done by the life cycle assessment (LCA) methodology, in order to establish with a broad perspective and in a rigorous and objective way the environmental footprint and the main environmental hotspots of the examined technology. Raw materials, equipment, transportation, energy use, as well as air- and waterborne emissions were quantified using as a functional unit, 1m(3) of urban wastewater. SimaPro 8.0.3.14 was used as the LCA analysis tool, and two impact assessment methods, i.e. IPCC 2013 version 1.00 and ReCiPe version 1.10, were employed. The main environmental hotspots of the MBR pilot unit were identified to be the following: (i) the energy demand, which is by far the most crucial parameter that affects the sustainability of the whole process, and (ii) the material of the membrane units. Overall, the MBR technology was found to be a sustainable solution for urban wastewater treatment, with the construction phase having a minimal environmental impact, compared to the operational phase. Moreover, several alternative scenarios and areas of potential improvement, such as the diversification of the electricity mix and the material of the membrane units, were examined, in order to minimize as much as possible the overall environmental footprint of this MBR system. It was shown that the energy mix can significantly affect the overall sustainability of the MBR pilot unit (i.e. up to 95% reduction of the total greenhouse gas emissions was achieved with the use of an environmentally friendly energy mix), and the contribution of the construction and operational phase to the overall environmental footprint of the system.

  2. Assessment of energy-saving strategies and operational costs in full-scale membrane bioreactors.

    PubMed

    Gabarrón, S; Ferrero, G; Dalmau, M; Comas, J; Rodriguez-Roda, I

    2014-02-15

    The energy-saving strategies and operational costs of stand-alone, hybrid, and dual stream full-scale membrane bioreactors (MBRs) with capacities ranging from 1100 to 35,000 m(3) day(-1) have been assessed for seven municipal facilities located in Northeast Spain. Although hydraulic load was found to be the main determinant factor for the energy consumption rates, several optimisation strategies have shown to be effective in terms of energy reduction as well as fouling phenomenon minimization or preservation. Specifically, modifications of the biological process (installation of control systems for biological aeration) and of the filtration process (reduction of the flux or mixed liquor suspended solids concentration and installation of control systems for membrane air scouring) were applied in two stand-alone MBRs. After implementing these strategies, the yearly specific energy demand (SED) in flat-sheet (FS) and hollow-fibre (HF) stand-alone MBRs was reduced from 1.12 to 0.71 and from 1.54 to 1.12 kW h(-1) m(-3), respectively, regardless of their similar yearly averaged hydraulic loads. The strategies applied in the hybrid MBR, namely, buffering the influent flow and optimisation of both biological aeration and membrane air-scouring, reduced the SED values by 14%. These results illustrate that it is possible to apply energy-saving strategies to significantly reduce MBR operational costs, highlighting the need to optimise MBR facilities to reconsider them as an energy-competitive option.

  3. New urban wastewater treatment with autotrophic membrane bioreactor at low chemical oxygen demand/N substrate ratio.

    PubMed

    Yang, Y; Lesage, G; Barret, M; Bernet, N; Grasmick, A; Hamelin, J; Heran, M

    2014-01-01

    The potential for total nitrogen removal from municipal wastewater has been evaluated in an autotrophic membrane bioreactor running with a low chemical oxygen demand (COD)/N ratio to simulate its combination with an upstream physicochemical process that retains a large proportion of organic matter. The tests were conducted in a laboratory scale submerged membrane bioreactor loaded with a synthetic influent. Nitrogen loading rate was 0.16 kgN-NH4+.m(-3).d(-1) and sodium acetate was added as a carbon source. Results have shown that nitrogen elimination can reach 85% for a COD/N ratio of 5, with COD removal exceeding 97%. However, a COD/N ratio of 3.5 was found to be the limiting factor for successfully reaching the overall target value of 10 mgN.L(-1) in the effluent. Nevertheless, low COD/N ratios make it possible to work with low total suspended solid concentrations in the bioreactor, which greatly facilitates membrane fouling control by a simple aeration and backwashing strategy.

  4. Effect of organic fouling on micro-pollutant rejection in membrane bioreactor treating municipal solid waste landfill leachate.

    PubMed

    Sanguanpak, Samunya; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2015-01-01

    Effect of membrane fouling on the removal of micro-pollutants from municipal solid waste landfill leachate, i.e. 4-methyl-2,6-di-tert-butylphenol (BHT), bisphenol A (BPA), and bis(2-ethylhexyl)phthalate (DEHP), in membrane bioreactor (MBR) was investigated. Modifications of membrane surface properties were analyzed to determine their relationship with their removals. Membrane fouling was simulated with foulants of different particle sizes on cellulose acetate (CA) microfiltration membrane to investigate the effect of foulant characteristics on BHT, BPA, and DEHP retention in the filtration experiment. The rejection efficiencies of the organic micro-pollutants in the MBR were 82-97% by fouled membrane, and 70-90% by cleaned membrane. The fouled membrane provided higher rejection of micro-pollutants from about 5% for BPA and BHT to 19% for DEHP. These improvements were due to the modification of membrane surface characteristics in terms of surface morphology, and contact angle after membrane fouling. The degree of rejection was found to be dependent upon the characteristics of foulant deposited on CA membrane surface. Increasing foulant particle size and its density shifted the mechanism of micro-pollutant rejection from membrane pore narrowing to pore blocking and cake formation while increasing pollutant adsorption capacity onto the foulant layer.

  5. Correlations between trans-membrane pressure (TMP) and sludge properties in submerged membrane electro-bioreactor (SMEBR) and conventional membrane bioreactor (MBR).

    PubMed

    Hasan, Shadi W; Elektorowicz, Maria; Oleszkiewicz, Jan A

    2012-09-01

    The influence of sludge properties in SMEBR and conventional MBR pilot systems on membrane fouling was investigated. Generated data were analyzed using statistical analysis Pearson's product momentum correlation coefficient (r(p)). Analysis showed that TMP had strong direct (r(p)=0.9182) and inverse (r(p)=-0.9205) correlations to mean particle size diameter in MBR and SMEBR, respectively. TMP in SMEBR had a strong direct correlation to the sludge mixed liquor suspended solids concentration (MLSS) (r(p)=0.7757) while a weak direct correlation (r(p)=0.1940) was observed in MBR. SMEBR showed a moderate inverse correlation (r(p)=-0.6118) between TMP and soluble carbohydrates (EPS(c)) and a very weak direct correlation (r(p)=0.3448) to soluble proteins (EPS(p)). Conversely, EPS(p) in MBR had more significant impact (r(p)=0.4856) on membrane fouling than EPS(c) (r(p)=0.3051). The results provide insight into optimization of operational conditions in SMEBR system to overcome membrane fouling.

  6. Extracellular polymeric substances (EPS) in a hybrid growth membrane bioreactor (HG-MBR): viscoelastic and adherence characteristics.

    PubMed

    Ying, Wang; Yang, Fei; Bick, Amos; Oron, Gideon; Herzberg, Moshe

    2010-11-15

    Extracellular polymeric substances (EPS) comprising the microbial biofilms in membrane bioreactor (MBR) systems are considered the most significant factor affecting sludge viscoelastic properties as well as membrane fouling. Understanding the water chemistry effects on EPS viscoelastic, conformational, and adherence properties are critical for defining the microbial biofilm's propensity of fouling the membrane surface. In this study, EPS extracted from a hybrid growth membrane bioreactor (HG-MBR) were analyzed for their adherence, viscoelastic properties and size distribution using quartz crystal microbalance with dissipation monitoring (QCM-D) and dynamic light scattering (DLS), respectively. Also, adsorption characteristics of EPS extracted from different locations in the HG-MBR (bioreactor liquor, fluidized carriers, and membrane surface) were defined and linked to the extent of the total polysaccharide content in the EPS. In accordance with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, more EPS were adsorbed at higher ionic strength, lower pH and in the presence of calcium cations. Based on the QCM-D results, the calculated thickness of the EPS adsorbed layer was increased at lower ionic strength, higher pH, and only had a minor increase in the presence of calcium cations. The calculated shear modules and shear viscosity suggest that at lower pH and in the presence of calcium, EPS becomes more viscous and elastic, respectively. DLS analysis correlated to the QCM-D results: A decrease in the hydrodynamic radius of the EPS colloids was observed at lower pH, and in the presence of calcium, most likely attributed to intermolecular attraction forces. Based on this study, low pH and presence of calcium may induce flocs' stability that resist erosion in the MBRs, while on the other hand, these conditions may induce the formation of an elastic and viscous EPS layer fouling the ultrafiltration (UF) membrane.

  7. Polymeric compounds in activated sludge supernatant -- Characterisation and retention mechanisms at a full-scale municipal membrane bioreactor.

    PubMed

    Lyko, Sven; Al-Halbouni, Djamila; Wintgens, Thomas; Janot, Andreas; Hollender, Juliane; Dott, Wolfgang; Melin, Thomas

    2007-09-01

    In this study, for the first time a full-scale membrane bioreactor (MBR) was investigated with focus on organic compounds in activated sludge over a period of approximately 2 years. Soluble extracellular polymeric substances (EPS) in the sludge supernatant and permeate as well as bound EPS extracted from fouled membranes were determined photospectrometrically and revealed a typical composition of three main components in the order metals>humic acids>carbohydrates>proteins. Results showed an important influence on membrane fouling by soluble humic substances and carbohydrates in complexes with metal cations. It was found that Fe(2+) and Fe(3+) play a decisive role in natural organic matter (NOM) complexation and subsequent membrane blockage. The determination of molar mass distribution in supernatant and permeate by size exclusion chromatography (SEC) revealed a significant retention of macromolecular compounds by the porous membranes in the range of 10-50%.

  8. Change in the fouling propensity of sludge in membrane bioreactors (MBR) in relation to the accumulation of biopolymer clusters.

    PubMed

    Sun, Fei-yun; Wang, Xiao-mao; Li, Xiao-yan

    2011-04-01

    A membrane bioreactor (MBR) and an activated sludge process (ASP) were operated side by side to evaluate the change of sludge supernatant characteristics and the evolution of the sludge fouling propensity. The MBR sludge had a higher organic concentration and more biopolymer clusters (BPC) in the supernatant compared with ASP. BPC increased in both concentration and size in the MBR. The results show that the change in the liquid-phase property had a profound effect on the sludge fouling propensity. MBR operation transformed typical activated sludge to MBR sludge with a higher fouling propensity. Distinct from the ASP, membrane filtration retained soluble microbial products (SMP) within the MBR, and the vast membrane surface provided a unique environment for the transformation of SMP to large size BPC, leading to further sludge deposition on the membrane surface. Thus, membrane filtration is the crucial cause of the inevitable fouling problem in submerged MBRs.

  9. Semi-permeable membrane retention of synovial fluid lubricants hyaluronan and proteoglycan 4 for a biomimetic bioreactor.

    PubMed

    Blewis, Megan E; Lao, Brian J; Jadin, Kyle D; McCarty, William J; Bugbee, William D; Firestein, Gary S; Sah, Robert L

    2010-05-01

    Synovial fluid (SF) contains lubricant macromolecules, hyaluronan (HA), and proteoglycan 4 (PRG4). The synovium not only contributes lubricants to SF through secretion by synoviocyte lining cells, but also concentrates lubricants in SF due to its semi-permeable nature. A membrane that recapitulates these synovium functions may be useful in a bioreactor system for generating a bioengineered fluid (BF) similar to native SF. The objectives were to analyze expanded polytetrafluoroethylene membranes with pore sizes of 50 nm, 90 nm, 170 nm, and 3 microm in terms of (1) HA and PRG4 secretion rates by adherent synoviocytes, and (2) the extent of HA and PRG4 retention with or without synoviocytes adherent on the membrane. Experiment 1: Synoviocytes were cultured on tissue culture (TC) plastic or membranes +/- IL-1beta + TGF-beta1 + TNF-alpha, a cytokine combination that stimulates lubricant synthesis. HA and PRG4 secretion rates were assessed by analysis of medium. Experiment 2: Bioreactors were fabricated to provide a BF compartment enclosed by membranes +/- adherent synoviocytes, and an external compartment of nutrient fluid (NF). A solution with HA (1 mg/mL, MW ranging from 30 to 4,000 kDa) or PRG4 (50 microg/mL) was added to the BF compartment, and HA and PRG4 loss into the NF compartment after 2, 8, and 24 h was determined. Lubricant loss kinetics were analyzed to estimate membrane permeability. Experiment 1: Cytokine-regulated HA and PRG4 secretion rates on membranes were comparable to those on TC plastic. Experiment 2: Transport of HA and PRG4 across membranes was lowest with 50 nm membranes and highest with 3 microm membranes, and transport of high MW HA was decreased by adherent synoviocytes (for 50 and 90 nm membranes). The permeability to HA mixtures for 50 nm membranes was approximately 20 x 10(-8) cm/s (- cells) and approximately 5 x 10(-8) cm/s (+ cells), for 90 nm membranes was approximately 35 x 10(-8) cm/s (- cells) and approximately 19 x 10(-8) cm

  10. Toward a novel membrane process for organic carbon removal-fate of slowly biodegradable substrate in super fast membrane bioreactor.

    PubMed

    Sözen, S; Teksoy Başaran, S; Akarsubaşı, A; Ergal, I; Insel, G; Karaca, C; Orhon, D

    2016-08-01

    The study tested the performance of super fast membrane bioreactor (SFMBR) using starch as a slowly biodegradable substrate, exploring the fate of starch, and the response of the microbial community. SFMBR was operated at extremely low sludge ages of 0.5-2.0 days, with a hydraulic retention time of 1.0 h. Average values for permeate chemical oxygen demand (COD) always remained in the narrow range between 14 and 18 mg/L, regardless of the selected mode of MBR operation at different sludge ages. Soluble COD levels in the reactor were consistently higher than the corresponding permeate COD. Parameters defining process kinetics, determined by model calibration of oxygen uptake rate (OUR) profiles, varied as a function of sludge age. Model simulation of SFMBR performance indicated total removal of hydrolysis products so that permeate COD consisted of residual microbial products. PCR-DGGE experiments revealed significant shifts in the composition of the microbial community imposed by variations in the sludge age, reflecting on corresponding process kinetics.

  11. Membrane fouling and performance evaluation of conventional membrane bioreactor (MBR), moving biofilm MBR and oxic/anoxic MBR.

    PubMed

    Khan, Sher Jamal; Ahmad, Aman; Nawaz, Muhammad Saqib; Hankins, Nicholas P

    2014-01-01

    In this study, three laboratory scale submerged membrane bioreactors (MBRs) comprising a conventional MBR (C-MBR), moving bed MBR (MB-MBR) and anoxic-oxic MBR (A/O-MBR) were continuously operated with synthesized domestic wastewater (chemical oxygen demand, COD = 500 mg/L) for 150 days under similar operational and environmental conditions. Kaldnes(®) plastic media with 20% dry volume was used as a biofilm carrier in the MB-MBR and A/O-MBR. The treatment performance and fouling propensity of the MBRs were evaluated. The effect of cake layer formation in all three MBRs was almost the same. However, pore blocking caused a major difference in the resultant water flux. The A/O-MBR showed the highest total nitrogen and phosphorus (PO4-P) removal efficiencies of 83.2 and 69.7%, respectively. Due to the high removal of nitrogen, fewer protein contents were found in the soluble and bound extracellular polymeric substances (EPS) of the A/O-MBR. Fouling trends of the MBRs showed 12, 14 and 20 days filtration cycles for C-MBR, MB-MBR and A/O-MBR, respectively. A 25% reduction of the soluble EPS and a 37% reduction of the bound EPS concentrations in A/O-MBR compared with C-MBR was a major contributing factor for fouling retardation and the enhanced filtration capacity of the A/O-MBR.

  12. Biodegradation kinetic constants and sorption coefficients of micropollutants in membrane bioreactors.

    PubMed

    Fernandez-Fontaina, Eduardo; Pinho, Ines; Carballa, Marta; Omil, Francisco; Lema, Juan M

    2013-04-01

    In order to elucidate the capability of biomass developed in membrane bioreactors (MBR) to degrade and sorb emerging micropollutants, biodegradation (kbiol) and sorption (ksor) kinetic constants as well as solid-liquid partition coefficients (Kd) of 13 selected pharmaceutical and personal care products (PPCPs) were determined with MBR heterotrophic biomass adding a pulse (100 ppb of each compound) and following the liquid and solid phase concentrations over time. The results obtained were compared to literature data referring to conventional activated sludge (CAS) systems. Two experiments were performed: one in the MBR itself and the second one in a batch reactor with the same type and concentration of biomass as in the MBR. Overall, both biodegradation and sorption coefficients were in the same range as previously reported by other studies in CAS systems, indicating that MBR biomass does not show better capabilities for the biological degradation and/or sorption of PPCPs compared to the biomass developed in CAS reactors. Therefore, the higher PPCPs removal efficiencies found in MBRs are explained by the high biomass concentrations obtained at the long sludge retention times at which this type of reactors are usually operated.

  13. Rapid Startup and Loading of an Attached Growth, Simultaneous Nitrification/Denitrification Membrane Aerated Bioreactor

    NASA Technical Reports Server (NTRS)

    Meyer, Caitlin; Vega, Leticia

    2014-01-01

    The Membrane Aerated Bioreactor (MABR) is an attached-growth biological system for simultaneous nitrification and denitrification. This design is an innovative approach to common terrestrial wastewater treatments for nitrogen and carbon removal. Implementing a biologically-based water treatment system for long-duration human exploration is an attractive, low energy alternative to physiochemical processes. Two obstacles to implementing such a system are (1) the "start-up" duration from inoculation to steady-state operations and (2) the amount of surface area needed for the biological activity to occur. The Advanced Water Recovery Systems (AWRS) team at JSC explored these two issues through two tests; a rapid inoculation study and a wastewater loading study. Results from these tests demonstrate that the duration from inoculation to steady state can be reduced to two weeks and that the surface area to volume ratio baseline used in the Alternative Water Processor (AWP) test was higher than what was needed to remove the organic carbon and ammonium from the system.

  14. Filtration characterization method as tool to assess membrane bioreactor sludge filterability-the delft experience.

    PubMed

    Lousada-Ferreira, Maria; Krzeminski, Pawel; Geilvoet, Stefan; Moreau, Adrien; Gil, Jose A; Evenblij, Herman; van Lier, Jules B; van der Graaf, Jaap H J M

    2014-04-30

    Prevention and removal of fouling is often the most energy intensive process in Membrane Bioreactors (MBRs), responsible for 40% to 50% of the total specific energy consumed in submerged MBRs. In the past decade, methods were developed to quantify and qualify fouling, aiming to support optimization in MBR operation. Therefore, there is a need for an evaluation of the lessons learned and how to proceed. In this article, five different methods for measuring MBR activated sludge filterability and critical flux are described, commented and evaluated. Both parameters characterize the fouling potential in full-scale MBRs. The article focuses on the Delft Filtration Characterization method (DFCm) as a convenient tool to characterize sludge properties, namely on data processing, accuracy, reproducibility, reliability, and applicability, defining the boundaries of the DFCm. Significant progress was made concerning fouling measurements in particular by using straight forward approaches focusing on the applicability of the obtained results. Nevertheless, a fouling measurement method is still to be defined which is capable of being unequivocal, concerning the fouling parameters definitions; practical and simple, in terms of set-up and operation; broad and useful, in terms of obtained results. A step forward would be the standardization of the aforementioned method to assess the sludge filtration quality.

  15. Enhanced sludge properties and distribution study of sludge components in electrically-enhanced membrane bioreactor.

    PubMed

    Giwa, Adewale; Ahmed, Iftikhar; Hasan, Shadi Wajih

    2015-08-15

    This study investigated the impact of electric field on the physicochemical and biological characteristics of sludge wasted from an electrically-enhanced membrane bioreactor treating medium-strength raw wastewater. This method offers a chemical-free electrokinetic technique to enhance sludge properties and remove heavy metals. For example, sludge volume index (SVI), time-to-filter (TTF), mean sludge particle diameter (PSD), viscosity, and oxidation-reduction potential (ORP) of 21.7 mL/g, 7 min, 40.2 μm, 3.22 mPa s, and -4.9 mV were reported, respectively. Also, X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses provided mechanisms for heavy metal removal so as to establish relevant pathways for nutrient recovery. Furthermore, variations in dissolved oxygen (DO), conductivity, viscosity, ORP, total suspended solids (MLSS), and volatile suspended solids (MLVSS) were interrelated to evaluate the quality of wasted sludge. A pathway study on the transport and chemical distribution of nutrients and metals in sludge showed great potential for metal removal and nutrient recovery.

  16. Removal of low concentrations of phenanthrene, fluoranthene and pyrene from urban wastewater by membrane bioreactors technology.

    PubMed

    González-Pérez, Daniel M; Garralón, Gloria; Plaza, Fidel; Pérez, Jorge I; Moreno, Begoña; Gómez, Miguel A

    2012-01-01

    The fate and removal of phenanthrene (Phen), fluoranthene (F) and pyrene (Py) in urban wastewater treatment by membrane bioreactor (MBR) with low influent polycyclic aromatic hydrocarbons (PAHs) concentration were studied. A full experimental ultrafiltration MBR with a pre-denitrification configuration and capacity to treat 20 m(3)/d was employed. The system was operated with real urban wastewater, to which a concentration of PAHs was added. A constant purge was achieved in order to obtain 12 d of sludge retention time and the hydraulic retention time was 34 h. Concentration of PAHs was determined by Gas Chromatography and Mass Spectrometry with Twister, and mass balance on the MBR system were calculated. Data were supplemented by respirometric analyses, isolation of PAHs degrading microorganisms and bench-scale experiments. All effluent samples presented concentrations of PAHs, with removal levels of 91% and 92% for F and Py respectively, while for Phen performance did not surpass 82%. In spite of the high hydrophobicity of the tested compounds, their accumulation in the biomass was scarce and the sludge presented a low PAH concentration. The experiments reveal that PAHs removal is mainly due to air stripping, with biodegradation and adsorption making an insignificant contribution.

  17. Old landfill leachate treatment through multistage process: membrane adsorption bioreactor and nanofitration.

    PubMed

    Peyravi, Majid; Jahanshahi, Mohsen; Alimoradi, Mahsa; Ganjian, Etesam

    2016-12-01

    A bench-scale integrated process based on submerged aerobic powdered activated carbon-membrane bioreactor (PAC-MBR) has been utilized and established for the treatment of landfill leachate. The results showed that the submerged PAC-MBR system effectively removed biodegradable trace organic compounds by the average removal rate about 71 % at optimum food to microorganism (F/M) ratio of 0.4 gCOD/g day under a HRT of 24 h. Adding nanofiltration (NF) process increased the treatment efficiency up to 99 %. Further, adding powdered activated carbon to activated sludge (AS) resulted in a higher adsorption capacity in comparison with AS. Adsorption isotherms were investigated and fitted by the Langmuir and Freundlich isotherm models in which the Langmuir model performed better. The specific oxygen uptake rate (SOUR) showed that adding PAC reduces the effects of COD on microorganism activities. NH3-N, TKN and Heavy metals removal efficiency amounted to 97 ± 2, 96 ± 2, and 99 ± 2 %, respectively.

  18. Analysis of pharmaceuticals in wastewater and removal using a membrane bioreactor

    PubMed Central

    Radjenovic, Jelena; Barceló, Damiá

    2006-01-01

    Much attention has recently been devoted to the life and behaviour of pharmaceuticals in the water cycle. In this study the behaviour of several pharmaceutical products in different therapeutic categories (analgesics and anti-inflammatory drugs, lipid regulators, antibiotics, etc.) was monitored during treatment of wastewater in a laboratory-scale membrane bioreactor (MBR). The results were compared with removal in a conventional activated-sludge (CAS) process in a wastewater-treatment facility. The performance of an MBR was monitored for approximately two months to investigate the long-term operational stability of the system and possible effects of solids retention time on the efficiency of removal of target compounds. Pharmaceuticals were, in general, removed to a greater extent by the MBR integrated system than during the CAS process. For most of the compounds investigated the performance of MBR treatment was better (removal rates >80%) and effluent concentrations of, e.g., diclofenac, ketoprofen, ranitidine, gemfibrozil, bezafibrate, pravastatin, and ofloxacin were steadier than for the conventional system. Occasionally removal efficiency was very similar, and high, for both treatments (e.g. for ibuprofen, naproxen, acetaminophen, paroxetine, and hydrochlorothiazide). The antiepileptic drug carbamazepine was the most persistent pharmaceutical and it passed through both the MBR and CAS systems untransformed. Because there was no washout of biomass from the reactor, high-quality effluent in terms of chemical oxygen demand (COD), ammonium content (N-NH4), total suspended solids (TSS), and total organic carbon (TOC) was obtained. PMID:17115140

  19. Landfill leachate treatment by sequential membrane bioreactor and electro-oxidation processes.

    PubMed

    Zolfaghari, Mehdi; Jardak, Karama; Drogui, Patrick; Brar, Satinder Kaur; Buelna, Gerardo; Dubé, Rino

    2016-12-15

    Combination of high performance membrane bioreactor (MBR) equipped with ultrafiltration and electro-oxidation process (EOP) by boron-doped diamond electrode (BDD) was used to effectively treat highly contaminated old landfill leachate. MBR and EOP were optimized for raw and pretreated landfill leachate. Seasonal changes dramatically affected the both processes' performance, as the landfill leachate was ¾ more concentrated in winter. For MBR, organic load rate of 1.2 gCOD/L/day and sludge retention time of 80 days was considered as the optimum operating condition in which COD, TOC, NH4(+) and phosphorous removal efficiencies reached the average of 63, 35, 98 and 52%, respectively. The best performance of EOP was in current intensity of 3 A with treatment of time of 120 min. Effluent of electro-oxidation was more toxic due to the presence of radicals and organochlorinated compounds. These compounds were removed by stripping or assimilation of sludge if EOP was used as a pretreatment method. Furthermore, the energy consumption of EOP was decreased from 22 to 16 KWh/m(3) for biologically treated and raw landfill leachate, respectively.

  20. Use of cloth-media filter for membrane bioreactor treating municipal wastewater.

    PubMed

    Zahid, Waleed M; El-Shafai, Saber A

    2011-02-01

    This study evaluated three different textile materials (Acrylate, Polyester, and Nylon) as filter media for MBR treating municipal wastewater. Chemical oxygen demand (COD) loading rates were 1.71, 1.65 and 1.84 g/l d while feed/microorganisms (F/M) ratios were 0.32, 0.31 and 0.33 in Reactor 1, Reactor 2 and Reactor 3, respectively. The actual hydraulic retention times were 8.6, 8.9 and 8.0 h in R1, R2 and R3. At 5.3-5.5 g/l mixed liquor suspended (MLSS) and 26.3 days solid retention time (SRT) the membrane bioreactors were effective in removing 93-95% of COD, 99% of total suspended solids (TSS) and turbidity, 89-94% of total kjeldahl nitrogen (TKN) and 90-96% of total ammonia nitrogen. Phosphorous removal was limited to 51-55% while faecal coliform was reduced by four logs. Quality of the treated effluents met both Saudi and Egyptian reuse standards for restricted irrigation and could be easily disinfected to meet the unrestricted irrigation standards.

  1. Kinetics of phenolic and phthalic acid esters biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate.

    PubMed

    Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2016-05-01

    The kinetic of phenolic and phthalic acid esters (PAEs) biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate was investigated. Laboratory-scale MBR was fed with mixture of fresh and stabilized landfill leachate containing carbon to nitrogen (C/N) ratio of 10, 6, 3 and operated under different solid retention time (SRT) of 90, 15 and 5 d. Batch experiments using MBR sludge obtained from each steady-state operating condition revealed highest biodegradation rate constant (k) of 0.059-0.092 h(-1) of the phenolic and PAEs compounds at C/N of 6. Heterotrophic bacteria were the major group responsible for biodegradation of compounds whereas the presence of ammonia-oxidizing bacteria (AOB) helped accelerating their removals. Heterotrophic nitrifying bacteria found under high ammonia condition had an important role in enhancing the biodegradation of phenols and PAEs by releasing phenol hydroxylase (PH), esterase (EST) and phthalate dioxygenase (PDO) enzymes and the presence of AOB helped improving biodegradation of phenolic and PAEs compounds through their co-metabolism.

  2. Study on Flows inside and outside an Air Diffuser for Membrane Bioreactor

    NASA Astrophysics Data System (ADS)

    Kira, Fumihiro; Furuno, Shinsuke; Hayashi, Kosuke; Sampei, Tomoyuki; Tomiyama, Akio

    Effects of the total gas flow rate on the water level in a diffuser pipe for a membrane bioreactor, the gas flow rate from each aeration hole and the bubble diameter are investigated. The diffuser has evenly positioned five aeration holes on the top and a larger hole on the bottom for introducing the liquid into the pipe. The gas flow rate from each aeration hole is measured by capturing generated bubbles. The water level and gas velocity inside the diffuser are computed by processing video images. The bubble diameter is calculated using the gas flow rate and the bubble generation frequency measured from the video images. The conclusions obtained are as follows: (1) the gas flow rate from the aeration hole depends on the water level inside the diffuser and becomes constant for all the holes as the total gas flow rate increases since the high total gas flow rate make the water level uniform, which results in a constant gas pressure in the diffuser, (2) the onset of slugging in the diffuser is well correlated in terms of the local gas velocity and the Mishima-Ishii's slugging model, (3) the increase in the total gas flow rate decreases the water level, causing suppression of the onset of slugging, (4) the diameter of aeration hole strongly affects the gas flow rate from each aeration hole and water level, and (5) the Davidson-Schuler correlation gives reasonable estimations of the bubble diameter, provided that the influence of slugging is not significant.

  3. Enhanced ethanol fermentation in a pervaporation membrane bioreactor with the convenient permeate vapor recovery.

    PubMed

    Fan, Senqing; Xiao, Zeyi; Zhang, Yan; Tang, Xiaoyu; Chen, Chunyan; Li, Weijia; Deng, Qing; Yao, Peina

    2014-03-01

    A continuous and closed-circulating fermentation (CCCF) system with a pervaporation membrane bioreactor was built for ethanol fermentation without a refrigeration unit to condense the permeate vapor. Two runs of experiment with a feature of complete and continuous coupling of fermentation and pervaporation were carried out, lasting for 192h and 264h, respectively. The experimental measurement indicated that the enhanced fermentation could be achieved with additional advantages of convenient permeate recovery and energy saving of the process. During the second experiment, the average cell concentration, glucose consumption rate, ethanol productivity, ethanol yield and total ethanol amount produced reached 19.8gL(-1), 6.06gL(-1)h(-1), 2.31gL(-1)h(-1), 0.38, and 609.8gL(-1), respectively. During the continuous fermentation process, ethanol removal in situ promoted the cell second growth obviously, but the accumulation of the secondary metabolites in the broth became the main inhibitor against the cell growth and fermentation.

  4. Comparison of nitrification performance and microbial community between submerged membrane bioreactor and conventional activated sludge system.

    PubMed

    Li, H; Yang, M; Zhang, Y; Liu, X; Gao, M; Kamagata, Y

    2005-01-01

    A submerged membrane bioreactor (SMBR) and a conventional activated sludge system (CAS) were compared in parallel over a period of more than 260 days on treating synthetic ammonia-bearing inorganic wastewater without sludge purge under decreased hydraulic retention times (HRTs). Conversion of NH4(+)-N to NO3(-)-N was achieved with an efficiency of over 98% at an HRT > or = 10 h in the SMBR, while similar performance was obtained at an HRT > or = 20 h in the CAS. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR) amplified 16S rDNA was used to monitor variations of community structures in the two systems. With the prolongation of operation, the number of DGGE bands in the SMBR gradually increased from the initial 11 bands to the final 22 bands, whereas that in the CAS varied in a range between 13 and 183 Sequence analysis indicates that Nitrosomonas sp. and Nitrospira sp. were the dominating nitrification species responsible for ammonia and nitrite oxidation, respectively. Heterotrophic bacteria like Pseudomonas sp. and Flavobacteria sp. existed in both of the systems although only inorganic wastewater was fed. Substantive accumulation of extracellular polymeric substances (EPS) in the SMBR was confirmed by scanning electron microscopy and EPS analysis.

  5. Simultaneous nitrification and denitrification with anoxic phosphorus uptake in a membrane bioreactor system.

    PubMed

    Patel, Jignesh; Nakhla, George

    2006-10-01

    The performance of an innovative membrane bioreactor (MBR) process using anoxic phosphorus uptake with nitrification and denitrification for the treatment of municipal wastewater with respect to operational performance and effluent quality is addressed in this paper. The system was operated at steady-state conditions with a synthetic acetate-based wastewater at a hydraulic retention time (HRT) of 12 hours and on degritted municipal wastewater at a total system HRT of 6 hours. The MBR system was able to achieve 99% biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammonia-nitrogen (NH4(+)-N); 98% total Kjeldahl nitrogen (TKN); and 97% phosphorus removal, producing effluent BOD, COD, NH4+-N, TKN, nitrate-nitrogen, nitrite-nitrogen, and phosphate-phosphorus of <3, 14, 0.2, 0.26, 5.8, 0.21, and <0.01 mg/L, respectively, at the 6-hour HRT. The comparison of the synthetic and municipal wastewater run is presented in this paper. Steady-state mass balance on municipal wastewater was performed to reveal some key features of the modified MBR system.

  6. A knowledge-based control system for air-scour optimisation in membrane bioreactors.

    PubMed

    Ferrero, G; Monclús, H; Sancho, L; Garrido, J M; Comas, J; Rodríguez-Roda, I

    2011-01-01

    Although membrane bioreactors (MBRs) technology is still a growing sector, its progressive implementation all over the world, together with great technical achievements, has allowed it to reach a mature degree, just comparable to other more conventional wastewater treatment technologies. With current energy requirements around 0.6-1.1 kWh/m3 of treated wastewater and investment costs similar to conventional treatment plants, main market niche for MBRs can be areas with very high restrictive discharge limits, where treatment plants have to be compact or where water reuse is necessary. Operational costs are higher than for conventional treatments; consequently there is still a need and possibilities for energy saving and optimisation. This paper presents the development of a knowledge-based decision support system (DSS) for the integrated operation and remote control of the biological and physical (filtration and backwashing or relaxation) processes in MBRs. The core of the DSS is a knowledge-based control module for air-scour consumption automation and energy consumption minimisation.

  7. Study on enhanced denitrification using particulate organic matter in membrane bioreactor by mechanism modeling.

    PubMed

    Zheng, Min; Liu, Yan-Chen; Wang, Cheng-Wen; Xu, Kang-Ning

    2013-11-01

    Particulate organic matter (POM) in wastewater is a potential denitrification carbon source, while the optimal operational mode using denitrification mechanism with POM is still unclear in wastewater treatment plants. In this work, we investigated the denitrification rates (DNRs) in a full-scale membrane bioreactor (MBR) coupled with two-stage pre-anoxic (pre-AN), and then evaluated the POM denitrification efficiency using mechanism modeling. The results indicate that POM related fraction accounted for the majority of the obtained specific DNR of 1.39±0.46mgNg(-1) MLVSS h(-1) in the second pre-AN without available soluble carbon source. The modeling approaches with calibration and validation procedures estimated a high residual POM concentration of 0.17g COD g(-1) MLVSS in the activated sludge, which provided specific DNR of 1.14mgNg(-1) MLVSS h(-1). High POM retention time in the reactor was the result of high solid retention time used in the MBR. In particular, post-AN of high biomass concentration could provide the highest POM denitrification efficiency in MBR. The MBR process combined with additional sludge reduction technology could further enhance denitrification by POM.

  8. Stripping/flocculation/membrane bioreactor/reverse osmosis treatment of municipal landfill leachate.

    PubMed

    Hasar, Halil; Unsal, Sezahat A; Ipek, Ubeyde; Karatas, Serdar; Cinar, Ozer; Yaman, Cevat; Kinaci, Cumali

    2009-11-15

    This study presents a configuration for the complete treatment of landfill leachate with high organic and ammonium concentrations. Ammonia stripping is performed to overcome the ammonia toxicity to aerobic microorganisms. By coagulation-flocculation process, COD and suspended solids (SS) were removed 36 and 46%, respectively. After pretreatment, an aerobic/anoxic membrane bioreactor (Aer/An MBR) accomplished the COD and total inorganic nitrogen (total-N(i)) removals above 90 and 92%, respectively, at SRT of 30 days. Concentrations of COD and total-N(i) (not considering organic nitrogen) in the Aer/An MBR effluent decreased to 450 and 40 mg/l, respectively, by significant organic oxidation and nitrification/denitrification processes. As an advanced treatment for the leachate, the reverse osmosis (RO) was applied to the collected Aer/An MBR effluents. Reverse osmosis provided high quality effluent by reducing the effluent COD from MBR to less than 4.0mg/l at SRT of 30 days.

  9. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent.

    PubMed

    Satyawali, Yamini; Balakrishnan, Malini

    2009-10-15

    This work investigated the effect of powdered activated carbon (PAC) addition on the operation of a membrane bioreactor (MBR) treating sugarcane molasses based distillery wastewater (spentwash). The 8L reactor was equipped with a submerged 30 microm nylon mesh filter with 0.05 m(2) filtration area. Detailed characterization of the commercial wood charcoal based PAC was performed before using it in the MBR. The MBR was operated over 200 days at organic loading rates (OLRs) varying from 4.2 to 6.9 kg m(-3)d(-1). PAC addition controlled the reactor foaming during start up and enhanced the critical flux by around 23%; it also prolonged the duration between filter cleaning. Operation at higher loading rates was possible and for a given OLR, the chemical oxygen demand (COD) removal was higher with PAC addition. However, biodegradation in the reactor was limited and the high molecular weight compounds were not affected by PAC supplementation. The functional groups on PAC appear to interact with the polysaccharide portion of the sludge, which may reduce its propensity to interact with the nylon mesh.

  10. Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons.

    PubMed

    Mannina, Giorgio; Cosenza, Alida; Di Trapani, Daniele; Laudicina, Vito Armando; Morici, Claudia; Ødegaard, Hallvard

    2016-11-01

    The joint effect of wastewater salinity and hydrocarbons on nitrous oxide emission was investigated. The membrane bioreactor pilot plant was operated with two phases: i. biomass acclimation by increasing salinity from 10gNaClL(-1) to 20gNaClL(-1) (Phase I); ii. hydrocarbons dosing at 20mgL(-1) with a constant salt concentration of 20gNaClL(-1) (Phase II). The Phase I revealed a relationship between nitrous oxide emissions and salinity. During the end of the Phase I, the activity of nitrifiers started to recover, indicating a partial acclimatization. During the Phase II, the hydrocarbon shock induced a temporary inhibition of the biomass with the suppression of nitrous oxide emissions. The results revealed that the oxic tank was the major source of nitrous oxide emission, likely due to the gas stripping by aeration. The joint effect of salinity and hydrocarbons was found to be crucial for the production of nitrous oxide.

  11. Evaluation of herbicide (persistent pollutant) removal mechanisms through hybrid membrane bioreactors.

    PubMed

    Navaratna, Dimuth; Shu, Li; Jegatheesan, Veeriah

    2016-01-01

    A laboratory-scale membrane bioreactor (MBR) combined with ultraviolet (UV) disinfection and granular activated carbon (GAC) adsorption was researched for over seven months to evaluate the removal efficiencies and mechanisms of a moderately persistent s-triazine herbicide (Ametryn), which is commonly used in Australian sugarcane farmlands. Long-term experiments showed that MBR alone (15h hydraulic retention time (HRT)) can remove 65% of Ametryn from its influent which had a concentration of 1-2mg/L. A batch study was carried out to assess the mechanisms of removal of Ametryn through MBR and found that 0.1186mg of Ametryn/g-VSS is adsorbed onto sludge particles when 1mg/L of Ametryn is added to the mixed liquor and showed a 64% removal after 12h. This experiment confirmed that 99%, 92% and 83% removal of Ametryn could be achieved only from biodegradation, if the MBR maintains a HRT of 7.5, 2.5 and 1.5days respectively.

  12. Increase of xylitol productivity by cell-recycle fermentation of Candida tropicalis using submerged membrane bioreactor.

    PubMed

    Kwon, Soun-Gyu; Park, Seung-Won; Oh, Deok-Kun

    2006-01-01

    Candida tropicalis, an osmophilic strain isolated from honeycomb, produced xylitol at a maximal volumetric productivity of 3.5 g l(-1) h(-1) from an initial xylose concentration of 200 g l(-1). Even at a very high xylose concentration, e.g., 350 g l(-1), this strain produced xylitol at a moderate rate of 2.07 g l(-1) h(-1). In a fed-batch fermentation of xylose and glucose, 260 g l(-1) xylose was added, and the xylitol production was 234 g l(-1) for 48 h, corresponding to a rate of 4.88 g l(-1) h(-1). To increase xylitol productivity, cells were recycled in a submerged membrane bioreactor with suction pressure and air sparging. For each recycle round in cell-recycle fermentation, the average concentration of xylitol produced, fermentation time, volumetric productivity, and product yield were 180 g l(-1), 19.5 h, 8.5 g l(-1) h(-1), and 85%, respectively. When cell-recycle fermentation was started with the cell mass concentrated twofold after batch fermentation and performed for 10 recycle rounds, we achieved a very high productivity of 12 g l(-1) h(-1). The productivity and total amount of xylitol in cell-recycle fermentation were 3.4- and 11.0-fold higher than those in batch fermentation, respectively.

  13. Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works.

    PubMed

    Besançon, A; Le Corre, K S; Dotro, G; Jefferson, B

    2017-01-01

    This paper demonstrates that utilising a vertical flow (VF) wetland after a conventional activated sludge (CAS) delivers equivalent or better effluent quality to a membrane bioreactor (MBR) based on a side-by-side pilot trial. The CAS was operated under the solids retention times (SRT) of 6, 12, and 20 days, with the effluent from each pilot plant fed onto a soil aquifer treatment column to better understand their water reuse application potential. Results showed an upgraded CAS + VF system could deliver effluents with median values of 34 mgO2.L((-1)), 7 mg.L(-1) and 1.9 mg.L(-1) for organics, solids and ammonia nitrogen, respectively, which were statistically similar to those from the MBR. Water reuse standards were achieved by the upgraded system for most parameters, with the exception of total coliform removal. The upgraded system delivered superior metal removal when compared to the CAS. An economic analysis showed upgrading a CAS with a VF wetland was more favourable than investing in an MBR system for example works of 5000 and 50,000 population equivalents if the VF system was operated at hydraulic loading rates of 0.03 m.d(-1) and 0.08 m.d(-1), respectively. This was delivered for a tenth of the carbon footprint of the MBR treatment.

  14. Simultaneous activated carbon adsorption within a membrane bioreactor for an enhanced micropollutant removal.

    PubMed

    Li, Xueqing; Hai, Faisal I; Nghiem, Long D

    2011-05-01

    Significant adsorption of sulfamethoxazole and carbamazepine to powdered activated carbon (PAC) was confirmed by a series of adsorption tests. In contrast, adsorption of these micropollutants to the sludge was negligible. The removal of these compounds in membrane bioreactor (MBR) was dependent on their hydrophobicity and loading as well as the PAC dosage. Sulfamethoxazole exhibited better removal rate during operation under no or low (0.1g/L) PAC dosage. When the PAC concentration in MBR was raised to 1.0 g/L, a sustainable and significantly improved performance in the removal of both compounds was observed - the removal efficiencies of sulfamethoxazole and carbamazepine increased to 82 ± 11% and 92 ± 15% from the levels of 64 ± 7%, and negligible removal, respectively. The higher removal efficiency of carbamazepine at high (1.0 g/L) PAC dosage could be attributed to the fact that carbamazepine is relatively more hydrophobic than sulfamethoxazole, which subsequently resulted in its higher adsorption affinity toward PAC.

  15. Analysis of microbial community composition in a lab-scale membrane distillation bioreactor

    PubMed Central

    Zhang, Q; Shuwen, G; Zhang, J; Fane, AG; Kjelleberg, S; Rice, SA; McDougald, D

    2015-01-01

    Aims Membrane distillation bioreactors (MDBR) have potential for industrial applications where wastewater is hot or waste heat is available, but the role of micro-organisms in MDBRs has never been determined, and thus was the purpose of this study. Methods and Results Microbial communities were characterized by bacterial and archaeal 16S and eukaryotic 18S rRNA gene tag-encoded pyrosequencing of DNA obtained from sludge. Taxonomy-independent analysis revealed that bacterial communities had a relatively low richness and diversity, and community composition strongly correlated with conductivity, total nitrogen and bound extracellular polymeric substances (EPS). Taxonomy-dependent analysis revealed that Rubrobacter and Caldalkalibacillus were abundant members of the bacterial community, but no archaea were detected. Eukaryotic communities had a relatively high richness and diversity, and both changes in community composition and abundance of the dominant genus, Candida, correlated with bound EPS. Conclusions Thermophilic MDBR communities were comprised of a low diversity bacterial community and a highly diverse eukaryotic community with no archea detected. Communities exhibited low resilience to changes in operational parameters. Specifically, retenatate nutrient composition and concentration was strongly correlated with the dominant species. Significance and Impact of the Study This study provides an understanding of microbial community diversity in an MDBR, which is fundamental to the optimization of reactor performance. PMID:25604265

  16. Biotransformation of citronellol by the basidiomycete Cystoderma carcharias in an aerated-membrane bioreactor.

    PubMed

    Onken, J; Berger, R G

    1999-02-01

    The basidiomycete Cystoderma carcharias transformed citronellol into 3,7-dimethyl-1,6,7-octanetriol as the main product. 3,7-Dimethyl-6,7-epoxy-1-octanol was identified as important intermediary product of the biotransformation, and the allylic diols 2,6-dimethyl-2-octene-1,8-diol, 3,7-dimethyl-5-octene-1,7-diol and 3,7-dimethyl-7-octene-1,6-diol were found to be minor products. Microbial formation of rose oxide, a flavour-impact component, was observed for the first time. The formation of the main products was inhibited by 70% after addition of 0.1 mmol l-1 cytochrome monooxygenase inhibitors. Formation of 3,7-dimethyl-1,6,7-octanetriol was effective in a bioreactor with aeration over a coil of a hydrophobic microporous polypropene capillary membrane. Production rates of up to 150 mg l-1 day-1 were reached and led to a product concentration of 866 mg l-1 (conversion rate: 52%). The total loss of the added volatile substrate via the exhaust air was 4.5% when this aeration method was used.

  17. Pilot aerobic membrane bioreactor and nanofiltration for municipal landfill leachate treatment.

    PubMed

    Amaral, Míriam C S; Moravia, Wagner G; Lange, Liséte C; Zico, Mariana R; Magalhães, Natalie C; Ricci, Bárbara C; Reis, Beatriz G

    2016-07-02

    The purpose of this article is to evaluate the integration of the air stripping, membrane bioreactor (MBR) and nanofiltration (NF) processes for the treatment of landfill leachate (LFL). Pretreatment by air stripping, without adjustment of pH, removed 65% of N-NH3 present in LFL. After pretreatment, the effluent was treated in MBR obtaining 44% of COD removal, and part of the N-NH3 was converted to nitrite and nitrate, which was later removed in the post-treatment. Nanofiltration was shown to be an effective process to improve the removal of organic compounds, the high toxicity present in LFL and nitrite and nitrate generated in the MBR. The system (air stripping + MBR + nanofiltration) obtained great efficiency of removal in most parameters analyzed, with overall removal of COD, ammonia, color and toxicity approximately 88, 95, 100 and 100%, respectively. By this route, treated landfill leachate may be reused at the landfill as water for dust arrestment and also as earth work on construction sites.

  18. Biological wastewater treatment by a bioreactor with repeated coupling of aerobes and anaerobes aiming at on-site reduction of excess sludge.

    PubMed

    Yu, Anfeng; Feng, Quan; Liu, Zehua; Zhou, Yunan; Xing, Xin-Hui

    2006-01-01

    Activated sludge has been widely used in wastewater treatment throughout the world. However, the biggest disadvantage of this method is the by-production of excess sludge in a large amount, resulting in difficulties in operation and high costs for wastewater treatment. Technological innovations for wastewater treatment capable of reducing excess sludge have thus become research topics of interest in recent years. In our present research, we developed a new biological wastewater treatment process by repeated coupling of aerobes and anaerobes (rCAA) to reduce the excess sludge during the treatment of wastewater. During 460-day continuous running, COD (300-700 mg/L) and TOC (100-350 mg/L) were effectively removed, of which the removal rate was above 80 and 90%, respectively. SS in the effluent was 13 mg/L on average in the rCAA bioreactor without a settling tank. The on-site reduction of the excess sludge in the rCAA might be contributed by several mechanisms. The degradation of the grown aerobes after moving into the anaerobic regions was considered to be one of the most important factors. Besides, the repeatedly coupling of aerobes and anaerobes could also result in a complex microbial community with more metazoans and decoupling of the microbial anabolism and catabolism.

  19. 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.

  20. Removal of persistent pharmaceutical micropollutants from sewage by addition of PAC in a sequential membrane bioreactor.

    PubMed

    Serrano, D; Suárez, S; Lema, J M; Omil, F

    2011-10-15

    The performance of a membrane bioreactor operating in a sequential mode (SMBR) using an external flat-plate membrane was investigated. After 200 days of operation, a single addition of 1 g L(-1) Powdered Activated Carbon (PAC) was added directly into the mixed liquor in order to enhance the simultaneous removal of nutrients and pharmaceutical micropollutants from synthetic urban wastewater. Throughout the entire operation (288 days), Chemical Oxygen Demand (COD) removal efficiencies were up to 95%, ammonium nitrogen removal was maintained over 70-80%, whereas phosphorus removal achieved only high values (around 80%) after PAC addition. During the operation of the SMBR without PAC addition, micropollutants which exerted a more recalcitrant behaviour were carbamazepine, diazepam, diclofenac and trimethoprim, with no significant removal. On the other hand, moderate removals (42-64%) were observed for naproxen and erythromycin, whereas ibuprofen, roxithromycin and fluoxetine were removed in the range of 71-97%. The addition of PAC into the aeration tank was a successful tool to improve the removal of the more recalcitrant compounds up to 85%. The highest removal with PAC was observed for carbamazepine, trimethoprim as well as for roxithromycin, erythromycin and fluoxetine. The latter four compounds have amine groups and pKa in the range 6.7-10.1, thus the interaction between PAC and the positively charged amino groups might be the cause of their comparatively better results. Microbial ecology present in the biomass showed a higher abundance of Accumulibacter phosphatis as well as the ammonium oxidizing bacteria belonging to the genus Nitrosomonas after PAC addition.

  1. Hydrolysis of whey lactose by immobilized β-galactosidase in a bioreactor with a spirally wound membrane.

    PubMed

    Vasileva, Nastya; Ivanov, Yavor; Damyanova, Stanka; Kostova, Iliana; Godjevargova, Tzonka

    2016-01-01

    The β-galactosidase was covalently immobilized onto a modified polypropylene membrane, using glutaraldehyde. The optimal conditions for hydrolysis of lactose (4.7%) by immobilized β-galactosidase in a batch process were determined 13.6 U enzyme activity, 40°C, pH 6.8 and 10h. The obtained degree of hydrolysis was compared with results received by a free enzyme. It was found, that the lactose hydrolysis by an immobilized enzyme was 1.6 times more effective than the lactose hydrolysis by a free enzyme. It was determined that the stability of the immobilized enzyme was 2 times higher in comparison with the stability of free enzyme. The obtained immobilized system β-galactosidase/polypropylene membrane was applied to produce glucose-galactose syrup from waste whey. The whey characteristics and the different preliminary treatments of the whey were investigated. Then the whey lactose hydrolysis in a bioreactor by an immobilized enzyme on a spirally wound membrane was performed. The optimal membrane surface and the optimal flow rate of the whey through the membrane module were determined, respectively 100 cm(2) and 1.0 mL min(-1). After 10h, the degree of lactose hydrolysis was increased to 91%. The operation stability was studied. After 20th cycle the yield of bioreactor was 69.7%.

  2. Improvement of anaerobic digester performance by wastewater recirculation through an aerated membrane.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine wastewater from an anaerobic digester was recirculated through a silicone hose located in an external aeration chamber to determine its effect on wastewater malodorants and biogas composition. The silicone hose acted as a semipermeable membrane for the passage of small molecules. In the first...

  3. Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gas-permeable membrane technology is useful to recover ammonia from manure. In this study, the technology was enhanced using aeration instead of alkali chemicals to increase pH and the ammonia recovery rate. Digested effluents from covered anaerobic swine lagoons containing 1375 to 2089 milligram am...

  4. Long term operation of high concentration powdered activated carbon membrane bio-reactor for advanced water treatment.

    PubMed

    Seo, G T; Moon, C D; Chang, S W; Lee, S H

    2004-01-01

    A pilot scale experiment was conducted to evaluate the performance of a membrane bioreactor filled with high concentration powdered activated carbon. This hybrid system has great potential to substitute for existing GAC or O3/BAC processes in the drinking water treatment train. The system was installed at a water treatment plant located downstream of the Nakdong river basin, Korea. Effluent of rapid sand filter was used as influent of the system which consists of PAC bio-reactor, submerged MF membrane module and air supply facility. PAC concentration of 20 g/L was maintained at the beginning of the experiment and it was increased to 40 g/L. The PAC has not been changed during the operational periods. The membrane was a hollow fiber type with pore sizes of 0.1 and 0.4 microm. It was apparent that the high PAC concentration could prevent membrane fouling. 40 g/L PAC was more effective to reduce the filtration resistance than 20 g/L. At the flux of 0.36 m/d, TMP was maintained less than 40 kPa for about 3 months by intermittent suction type operation (12 min suction/3 min idling). Adsorption was the dominant role to remove DOC at the initial operational period. However the biological effect was gradually increased after around 3 months operation. Constant DOC removal could be maintained at about 40% without any trouble and then a tremendous reduction of DBPs (HAA5 and THM) higher than 85% was achieved. Full nitrification was observed at the controlled influent ammonia nitrogen concentration of 3 and 7 mg/L. pH was an important parameter to keep stable ammonia oxidation. From almost two years of operation, it is clear that the PAC membrane bioreactor is highly applicable for advanced water treatment under the recent situation of more stringent DBPs regulation in Korea.

  5. 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.

  6. Evaluation of a long-term operation of a submerged nanofiltration membrane bioreactor (NF MBR) for advanced wastewater treatment.

    PubMed

    Choi, J H; Fukushi, K; Ng, H Y; Yamamoto, K

    2006-01-01

    Nanofiltration (NF) is considered as one of the most promising separation technologies to obtain a very good-quality permeate in water and wastewater treatment. A submerged NF membrane bioreactor (NF MBR) using polyamide membranes was tested for a long-term operation and the performance of the NF MBR was compared with that of a microfiltration MBR (MF MBR). Total organic carbon (TOC) concentration in the permeate of the NF MBR ranged from 0.5 to 2.0 mg/L, whereas that of the MF MBR showed an average of 5 mg/L. This could be explained by the tightness of the NF membrane. Although the concentration of organic matter in the supernatant of the NF MBR was higher than that in the permeate due to high rejection by the NF membrane, the NF MBR showed excellent treatment efficiency and satisfactory operational stability for a long-term operation.

  7. The effect of activated carbon addition on membrane bioreactor processes for wastewater treatment and reclamation - A critical review.

    PubMed

    Skouteris, George; Saroj, Devendra; Melidis, Paraschos; Hai, Faisal I; Ouki, Sabèha

    2015-06-01

    This review concentrates on the effect of activated carbon (AC) addition to membrane bioreactors (MBRs) treating wastewaters. Use of AC-assisted MBRs combines adsorption, biodegradation and membrane filtration. This can lead to advanced removal of recalcitrant pollutants and mitigation of membrane fouling. The relative contribution of adsorption and biodegradation to overall removal achieved by an AC-assisted MBR process can vary, and "biological AC" may not fully develop due to competition of target pollutants with bulk organics in wastewater. Thus periodic replenishment of spent AC is necessary. Sludge retention time (SRT) governs the frequency of spent AC withdrawal and addition of fresh AC, and is an important parameter that significantly influences the performance of AC-assisted MBRs. Of utmost importance is AC dosage because AC overdose may aggravate membrane fouling, increase sludge viscosity, impair mass transfer and reduce sludge dewaterability.

  8. Quantitative evaluation of the interfacial interactions between a randomly rough sludge floc and membrane surface in a membrane bioreactor based on fractal geometry.

    PubMed

    Zhang, Meijia; Zhou, Xiaoling; Shen, Liguo; Cai, Xiang; Wang, Fangyuan; Chen, Jianrong; Lin, Hongjun; Li, Renjie; Wu, Xilin; Liao, Bao-Qiang

    2017-06-01

    In this paper, a new method for quantification of interfacial interactions between a randomly rough particle and membrane surface was proposed. It was found that sludge flocs in a membrane bioreactor were of apparent fractal characteristics, and could be modeled by the modified two-variable Weierstrass-Mandelbrot (WM) function. By combining the surface element integration (SEI) method, differential geometry and composite Simpson's rule, the quantitation method for calculating such interfacial interactions was further developed. The correctness and feasibility of the new method were verified. This method was then applied to evaluate the interfacial interactions between a randomly rough particle and membrane surface. It was found that, randomly rough particle possesses stronger interaction strength than regularly rough particle but weaker strength than smooth particle with membrane surface, indicating significant effects of surface morphology and roughness. The proposed method in this study has broad application prospect in membrane fouling study.

  9. Scale-up of osmotic membrane bioreactors by modeling salt accumulation and draw solution dilution using hollow-fiber membrane characteristics and operation conditions.

    PubMed

    Kim, Suhan

    2014-08-01

    A full-scale osmotic membrane bioreactor (OMBR) model was developed to simulate salt accumulation, draw solution (DS) dilution, and water flux over the hollow-fiber membrane length. The model uses the OMBR design parameters, DS properties, and forward osmosis (FO) membrane characteristics obtained from lab-scale tests. The modeling results revealed a tremendous water flux decline (10→0.82LMH) and short solids retention time (SRT: 5days) due to salt accumulation and DS dilution when OMBR is scaled up using commercially available DS and FO membrane. Simulated water flux is a result of interplay among reverse salt flux, internal and external concentration polarization (ICP and ECP). ECP adversely impacts water flux considerably in full-scale OMBR although it is often ignored in previous works. The OMBR model makes it possible to select better DS properties (higher flow rate and salt concentration) and FO membranes with higher water flux propensity in full-scale operation.

  10. Application of glyco-blotting for identification of structures of polysaccharides causing membrane fouling in a pilot-scale membrane bioreactor treating municipal wastewater.

    PubMed

    Kimura, Katsuki; Nishimura, Shin-Ichiro; Miyoshi, Risho; Hoque, Asiful; Miyoshi, Taro; Watanabe, Yoshimasa

    2015-03-01

    A new approach for the analysis of polysaccharides in membrane bioreactor (MBR) is proposed in this study. Enrichment of polysaccharides by glyco-blotting, in which polysaccharides are specifically collected via interactions between the aldehydes in the polysaccharides and aminooxy groups on glycoblotting beads, enabled MALDI-TOF/MS analysis at a high resolution. Structures of polysaccharides extracted from fouled membranes used in a pilot-scale MBR treating municipal wastewater and those in the supernatant of the mixed liquor suspension in the MBR were investigated. It was found that the overlap between polysaccharides found in the supernatants and those extracted from the fouled membrane was rather limited, suggesting that polysaccharides that dominate in supernatants may not be important in membrane fouling in MBRs. Analysis using a bacterial carbohydrate database suggested that capsular polysaccharides (CPS) and/or lipo-polysaccharides (LPS) produced by gram-negative bacteria are key players in the evolution of membrane fouling in MBRs.

  11. Fine-scale monitoring of shifts in microbial community composition after high organic loading in a pilot-scale membrane bioreactor.

    PubMed

    Sato, Yuya; Hori, Tomoyuki; Navarro, Ronald R; Habe, Hiroshi; Yanagishita, Hiroshi; Ogata, Atsushi

    2016-05-01

    In biological wastewater treatment, municipal wastewater sometimes undergoes unexpected changes in physicochemical parameters, such as organic carbon concentration. The aim of this study was to understand how microbial communities in activated sludge in a membrane bioreactor (MBR) adapt to high organic loading and maintain their degradation ability during reactor operation. A pilot-scale MBR was operated for 19 days. On day 8, the concentration of organic matter in the synthetic wastewater increased from 450 to 900 mg chemical oxygen demand (COD)/L. Even under conditions of high organic loading, COD removal rates were high, ranging from 85.3 to 91.4%. High-throughput sequencing of 16S rRNA genes revealed that microbial communities changed drastically with increased organic loading. After day 8, Aquabacterium- and Azospira-related operational taxonomic units (OTUs) belonging to the class β-proteobacteria became dominant; this potentially enhanced the degradation of organic substances and decreased activated sludge microbial diversity. Due to the use of dissolved oxygen (DO) for degradation of organic substances, DO levels in the reactor decreased. This led to an increase in a subset of OTUs related to not only aerobic but also anaerobic bacteria, e.g., those in the class Clostridia. During this period, anaerobic microorganisms may have contributed to the degradation of organic substances to maintain MBR performance. On the other hand, high-throughput sequencing also made it possible to identify yet-to-be cultured or minor microorganisms affiliated with the candidate phylogenetic division SR1 and ammonia-oxidizing archaea in activated sludge.

  12. Heavy metal leaching from aerobic and anaerobic landfill bioreactors of co-disposed municipal solid waste incineration bottom ash and shredded low-organic residues.

    PubMed

    Inanc, Bulent; Inoue, Yuzo; Yamada, Masato; Ono, Yusaku; Nagamori, Masanao

    2007-03-22

    In this study, heavy metal leaching from aerobic and anaerobic landfill bioreactor test cells for co-disposed municipal solid waste incineration (MSWI) bottom ash and shredded low-organic residues has been investigated. Test cells were operated for 1 year. Heavy metals which were comparatively higher in leachate of aerobic cell were copper (Cu), lead (Pb), boron (B), zinc (Zn), manganese (Mn) and iron (Fe), and those apparently lower were aluminum (Al), arsenic (As), molybdenum (Mo), and vanadium (V). However, no significant release of heavy metals under aerobic conditions was observed compared to anaerobic and control cells. Furthermore, there was no meaningful correlation between oxidation-reduction potential (ORP) and heavy metal concentrations in the leachates although some researchers speculate that aeration may result in excessive heavy metal leaching. No meaningful correlation between dissolved organic carbon (DOC) and leaching of Cu and Pb was another interesting observation. The only heavy metal that exceeded the state discharge limits (10mg/l, to be enforced after April 2005) in the aerobic cell leachate samples was boron and there was no correlation between boron leaching and ORP. Higher B levels in aerobic cell should be due to comparatively lower pH values in this cell. However, it is anticipated that this slightly increased concentrations of B (maximum 25mg/l) will not create a risk for bioreactor operation; rather it should be beneficial for long-term stability of the landfill through faster washout. It was concluded that aerobization of landfills of heavy metal rich MSWI bottom ash and shredded residues is possible with no dramatic increase in heavy metals in the leachate.

  13. Effect of air-assisted backwashing on the performance of an anaerobic fixed-bed bioreactor that simultaneously removes nitrate and arsenic from drinking water sources.

    PubMed

    Upadhyaya, Giridhar; Clancy, Tara M; Snyder, Kathryn V; Brown, Jess; Hayes, Kim F; Raskin, Lutgarde

    2012-03-15

    Contaminant removal from drinking water sources under reducing conditions conducive for the growth of denitrifying, arsenate reducing, and sulfate reducing microbes using a fixed-bed bioreactor may require oxygen-free gas (e.g., N2 gas) during backwashing. However, the use of air-assisted backwashing has practical advantages, including simpler operation, improved safety, and lower cost. A study was conducted to evaluate whether replacing N2 gas with air during backwashing would impact performance in a nitrate and arsenic removing anaerobic bioreactor system that consisted of two biologically active carbon reactors in series. Gas-assisted backwashing, comprised of 2 min of gas injection to fluidize the bed and dislodge biomass and solid phase products, was performed in the first reactor (reactor A) every two days. The second reactor (reactor B) was subjected to N2 gas-assisted backwashing every 3-4 months. Complete removal of 50 mg/L NO3- was achieved in reactor A before and after the switch from N2-assisted backwashing (NAB) to air-assisted backwashing (AAB). Substantial sulfate removal was achieved with both backwashing strategies. Prolonged practice of AAB (more than two months), however, diminished sulfate reduction in reactor B somewhat. Arsenic removal in reactor A was impacted slightly by long-term use of AAB, but arsenic removals achieved by the entire system during NAB and AAB periods were not significantly different (p>0.05) and arsenic concentrations were reduced from approximately 200 μg/L to below 20 μg/L. These results indicate that AAB can be implemented in anaerobic nitrate and arsenic removal systems.

  14. Energy consumption in terms of shear stress for two types of membrane bioreactors used for municipal wastewater treatment processes

    NASA Astrophysics Data System (ADS)

    Ratkovich, Nicolas; Bentzen, Thomas R.; Rasmussen, Michael R.

    2012-10-01

    Two types of submerged membrane bioreactors (MBR): hollow fiber (HF) and hollow sheet (HS), have been studied and compared in terms of energy consumption and average shear stress over the membrane wall. The analysis of energy consumption was made using the correlation to determine the blower power and the blower power demand per unit of permeate volume. Results showed that for the system geometries considered, in terms the of the blower power, the HF MBR requires less power compared to HS MBR. However, in terms of blower power per unit of permeate volume, the HS MBR requires less energy. The analysis of shear stress over the membrane surface was made using computational fluid dynamics (CFD) modelling. Experimental measurements for the HF MBR were compared with the CFD model and an error less that 8% was obtained. For the HS MBR, experimental measurements of velocity profiles were made and an error of 11% was found. This work uses an empirical relationship to determine the shear stress based on the ratio of aeration blower power to tank volume. This relationship is used in bubble column reactors and it is extrapolate to determine shear stress on MBR systems. This relationship proved to be overestimated by 28% compared to experimental measurements and CFD results. Therefore, a corrective factor is included in the relationship in order to account for the membrane placed inside the bioreactor.

  15. Baffled membrane bioreactor (BMBR) for advanced wastewater treatment: easy modification of existing MBRs for efficient nutrient removal.

    PubMed

    Kimura, K; Watanabe, Y

    2005-01-01

    In this study, a novel membrane bioreactor (MBR) in which nitrification and denitrification simultaneously proceed in a single reaction chamber is proposed for advanced municipal wastewater treatment. Anoxic/aerobic environments are alternatively created in the proposed MBR by inserting baffles inside the membrane chamber. The performance of the proposed baffled membrane bioreactor (BMBR) was examined at an existing municipal wastewater treatment facility based on long-term operation. Although the procedure was simple, insertion of the baffles actually created the alternative anoxic/aerobic environments in the chamber at a constant interval and showed a great improvement in the nutrient removal. The insertion did not cause any adverse effect on membrane permeability. In this study, almost complete elimination of NH4+-N was observed while around 8 mg/L of NO(3-)-N was detected in the treated water. The modification proposed in this study can immediately be applied to most existing MBRs and is highly recommended for more efficient wastewater treatment.

  16. Desalination of mixed tannery effluent with membrane bioreactor and reverse osmosis treatment.

    PubMed

    Scholz, W G; Rougé, P; Bódalo, A; Leitz, U

    2005-11-01

    A limiting factor for the reuse and recycling of treated tannery wastewater for irrigation and other uses is the high salt content, which persists even after conventional treatment. Reverse osmosis (RO) membrane treatment has been shown to significantly reduce the salt contents of tannery effluents. However, the high organic content of tannery effluent leads to rapid scaling and biofouling of RO membranes with a consequent reduction in flux rates and performance. Membrane bioreactors (MBR) have been shown to be highly effective in the removal of organic pollutants and suspended solids from tannery effluent. This research investigated the use of a combined MBR and RO treatment process to treat tannery effluents to an acceptable level for irrigation purposes. The MBR was operated at 17-20 h retention time, at a F/M ratio of 0.52 kg COD x kg SS(-1) x day(-1) and a volumetric loading rate of 3.28 kg COD x m(-3) x day(-1). This treatment reduced the COD, BOD, and ammonia concentrations of the effluent by 90-100%. The MBR was shown to be an excellent pretreatment prior to RO technology, due to the high removal efficiency of organic compounds and suspended solids, with average concentrations of 344 mg x L(-1) COD and 20 mg x L(-1) BOD achieved in the permeate. RO treatment reduced the salt content of the MBR permeate by up to 97.1%. The results of the research demonstrated that the MBR system developed was appropriate for the treatment of tannery effluents and, in combination with the RO treatment, reduced the salt content to acceptable levels for irrigation. The MBR pretreatment reduced bio-fouling and scaling of subsequent RO treatment and improved the overall performance of the RO unit. It is believed that this is the first investigation of a combined MBR and RO treatment for tannery effluents. This research provided data for an outline design of a full-scale MBR and RO plant with a treatment capacity of 5000 m3 per day for mixed tannery effluents.

  17. A pilot study of anaerobic membrane digesters for concurrent thickening and digestion of waste activated sludge (WAS).

    PubMed

    Dagnew, Martha; Parker, Wayne J; Seto, Peter

    2010-01-01

    The increased interest in biomass energy provides incentive for the development of efficient and high throughput digesters such as anaerobic membrane bioreactors (AnMBRs) to stabilize waste activated sludge (WAS). This paper presents the results of a pilot and short term filtration study that was conducted to assess the performance of AnMBRs when treating WAS at a 15 day hydraulic retention time (HRT) and 30 day sludge retention time (SRT) in comparison to two conventional digesters running at 15 (BSR-15) and 30 days (BSR-30) HRT/SRT. At steady state, the AnMBR digester showed a slightly higher volatile solids (VS) destruction of 48% in comparison to 44% and 35.3% for BSR-30 and BSR-15, respectively. The corresponding values of specific methane production were 0.32, 0.28 and 0.21 m(3) CH(4)/kg of VS fed. Stable membrane operation at an average flux of 40+/-3.6 LM(-2 )H(-1) (LMH) was observed when the digester was fed with a polymer-dosed thickened waste activated sludge (TWAS) and digester total suspended solids (TSS) concentrations were less than 15 gL(-1). Above this solids concentration a flux decline to 24.1+/-2.0 LM(-2) H(-1) was observed. Short term filtration tests conducted using sludge fractions of a 9.7 and 17.1 gL(-1) TSS sludge indicated 84 and 70% decline in filtration performance to be associated with the supernatant fraction of the sludge. At a higher sludge concentration, the introduction of unique fouling control strategy to tubular membranes, a relaxed mode of operation (i.e. 5 minutes permeation and 1 minute relaxation by) significantly increased the flux from 23.8+/-1.1 to 37.8+/-2.3 LMH for a neutral membrane and from 25.7+/-1.1 to 44.9+/-2.9 LMH for a negatively charged membrane. The study clearly indicates that it is technically feasible to employ AnMBRs to achieve a substantial reduction in digester volumes.

  18. Reducing aeration energy consumption in a large-scale membrane bioreactor: Process simulation and engineering application.

    PubMed

    Sun, Jianyu; Liang, Peng; Yan, Xiaoxu; Zuo, Kuichang; Xiao, Kang; Xia, Junlin; Qiu, Yong; Wu, Qing; Wu, Shijia; Huang, Xia; Qi, Meng; Wen, Xianghua

    2016-04-15

    Reducing the energy consumption of membrane bioreactors (MBRs) is highly important for their wider application in wastewater treatment engineering. Of particular significance is reducing aeration in aerobic tanks to reduce the overall energy consumption. This study proposed an in situ ammonia-N-based feedback control strategy for aeration in aerobic tanks; this was tested via model simulation and through a large-scale (50,000 m(3)/d) engineering application. A full-scale MBR model was developed based on the activated sludge model (ASM) and was calibrated to the actual MBR. The aeration control strategy took the form of a two-step cascaded proportion-integration (PI) feedback algorithm. Algorithmic parameters were optimized via model simulation. The strategy achieved real-time adjustment of aeration amounts based on feedback from effluent quality (i.e., ammonia-N). The effectiveness of the strategy was evaluated through both the model platform and the full-scale engineering application. In the former, the aeration flow rate was reduced by 15-20%. In the engineering application, the aeration flow rate was reduced by 20%, and overall specific energy consumption correspondingly reduced by 4% to 0.45 kWh/m(3)-effluent, using the present practice of regulating the angle of guide vanes of fixed-frequency blowers. Potential energy savings are expected to be higher for MBRs with variable-frequency blowers. This study indicated that the ammonia-N-based aeration control strategy holds promise for application in full-scale MBRs.

  19. Biological nitrogen removal from plating wastewater by submerged membrane bioreactor packed with granular sulfur.

    PubMed

    Moon, Jinyoung; Hwang, Yongwoo; Kim, Junbeum; Kwak, Inho

    Recent toughened water quality standards have necessitated improvements for existing sewer treatment facilities through advanced treatment processes. Therefore, an advanced treatment process that can be installed through simple modification of existing sewer treatment facilities needs to be developed. In this study, a new submerged membrane bioreactor process packed with granular sulfur (MBR-GS) was developed and operated to determine the biological nitrogen removal behaviors of plating wastewater containing a high concentration of NO3(-). Continuous denitrification was carried out at various nitrogen loading rates at 20 °C using synthetic wastewater, which was comprised of NO3(-) and HCO3(-), and actual plating wastewater, which was collected from the effluent water of a plating company called 'H Metals'. High-rate denitrification in synthetic plating wastewater was accomplished at 0.8 kg NO3(-)-N/m(3)·day at a nitrogen loading rate of 0.9 kg NO3(-)-N/m(3)·day. The denitrification rate further increased in actual plating wastewater to 0.91 kg NO3(-)-N/m(3)·day at a nitrogen loading rate of 1.11 kg NO3(-)-N/m(3)·day. Continuous filtration was maintained for up to 30 days without chemical cleaning with a transmembrane pressure in the range of 20 cmHg. Based on stoichiometry, SO4(2-) production and alkalinity consumption could be calculated theoretically. Experimental alkalinity consumption was lower than the theoretical value. This newly proposed MBR-GS process, capable of high-rate nitrogen removal by compulsive flux, is expected to be applicable as an alternative renovation technique for nitrogen treatment of plating wastewater as well as municipal wastewater with a low C/N ratio.

  20. Calibrating a side-stream membrane bioreactor using Activated Sludge Model No. 1.

    PubMed

    Jiang, T; Liu, X; Kennedy, M D; Schippers, J C; Vanrolleghem, P A

    2005-01-01

    Membrane bioreactors (MBRs) are attracting global interest but the mathematical modeling of the biological performance of MBRs remains very limited. This study focuses on the modeling of a side-stream MBR system using the Activated Sludge Model No. 1 (ASM1), and compares the results with the modeling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated (i.e. Y(H) = 0.72 gCOD/gCOD, Y(A) = 0.25 gCOD/gN, b(H) = 0.25 d(-1), b(A) = 0.080 d(-1) and f(p) = 0.06), and generally agreed with the parameters in traditional activated sludge processes, with the exception that a higher autotrophic biomass decay rate was observed in the MBR. Influent wastewater characterization was proven to be a critical step in model calibration, and special care should be taken in characterizing the inert particulate COD (X(I)) concentration in the MBR influent. It appeared that the chemical-biological method was superior to the physical-chemical method. A sensitivity analysis for steady-state operation and DO dynamics suggested that the biological performance of the MBR system (the sludge concentration, effluent quality and the DO dynamics) are very sensitive to the parameters (i.e. Y(H), Y(A), b(H), b(A) micro(maxH) and micro(maxA), and influent wastewater components (X(I), S(s), X(s) and S(NH)).

  1. [Analysis of Microbial Community in the Membrane Bio-Reactor (MBR) Rural Sewage Treatment System].

    PubMed

    Kong, Xiao; Cui, Bing-jian; Jin, De-cai; Wu, Shang-hua; Yang, Bo; Deng, Ye; Zhuang, Guo-qiang; Zhuang, Xu-liang

    2015-09-01

    Uncontrolled release and arbitrary irrigation reuse of rural wastewater may lead to water pollution, and the microbial pathogens could threaten the safety of freshwater resources and public health. To understand the microbial community structure of rural wastewater and provide the theory for microbial risk assessment of wastewater irrigation, microbial community diversities in the Membrane Bio-Reactor (MBR) process for rural wastewater treatment was studied by terminal restriction fragment length polymorphism (T-RFLP) and 16S rDNA gene clone library. Meanwhile, changes of Arcobacter spp. and total bacteria before and after treatment were detected through real-time quantitative PCR. The clone library results showed that there were 73 positive clones included Proteobacteria (91. 80%), Firmicutes (2. 70%), Bacteroidetes (1. 40%), and uncultured bacteria (4. 10%) in the untreated wastewater. The typical pathogenic genus Arcobacter belonging to e-Proteobacteria was the dominant component of the library, accounting for 68. 5% of all clones. The main groups and their abundance in different treatments were significantly distinct. The highest values of species abundance (S), Shannon-Wiener (H) and Evenness (E) were observed in the adjusting tank, which were 43. 0, 3. 56 and 0. 95, respectively. The real-time quantitative PCR results showed that the copy number of Arcobacter spp. was (1. 09 ± 0. 064 0) x 10(11) copies.L-1 in the untreated sewage, which was consistent with the result of 16S rDNA gene clone library. Compared to untreated wastewater, bacterial copy number in the treated effluent decreased 100 to 1 000 times, respectively, suggesting that MBR treatment system could remove the microbial quantity in such scale. In the recycled water, the physicochemical parameters and indicator bacteria met the water quality standard of farmland irrigation. However, further research is needed to estimate the potential health risks caused by residual pathogenic microorganisms in

  2. Enantiomeric fraction determination of 2-arylpropionic acids in a package plant membrane bioreactor.

    PubMed

    Hashim, Nor H; Stuetz, Richard M; Khan, Stuart J

    2013-05-01

    Enantiomeric compositions of three 2-arylpropionic acid (2-APA) drugs, ibuprofen, naproxen, and ketoprofen, were monitored in a membrane bioreactor (MBR) treating municipal effluent in a small rural town in Australia. Specific enantiomers were determined as amide diastereomers using the chiral derivatizing reagent, (R)-1-phenylethylamine (PEA), followed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The six individual enantiomers were quantified by isotope dilution and the enantiomeric fractions (EFs) were determined. Over four separate sampling events, ibuprofen EF ranged from 0.88 to 0.94 (median 0.93) in the influent and 0.38 to 0.40 (median 0.39) in the effluent. However, no significant change in ketoprofen EF was observed, with influent EFs of 0.56-0.60 (median 0.58) and effluent EFs 0.54-0.68 (median 0.56). This is the first report of enantiospecific analysis of ketoprofen in municipal wastewater and it is not yet clear why such different behavior was observed compared to ibuprofen. Naproxen EF was consistently measured at 0.99 in the influent and ranged from 0.86 to 0.94 (median 0.91) in the effluent. This study demonstrates that EF is a relatively stable parameter and does not fluctuate according to concentration or other short-term variables introduced by sampling limitations. The enantiospecific analysis of chiral chemicals presents a promising approach to elucidate a more thorough understanding of biological treatment processes and a potential tool for monitoring the performance of key biological pathways.

  3. Fouling potential evaluation of soluble microbial products (SMP) with different membrane surfaces in a hybrid membrane bioreactor using worm reactor for sludge reduction.

    PubMed

    Li, Zhipeng; Tian, Yu; Ding, Yi; Chen, Lin; Wang, Haoyu

    2013-07-01

    The fouling characteristics of soluble microbial products (SMP) in the membrane bioreactor coupled with Static Sequencing Batch Worm Reactor (SSBWR-MBR) were tested with different types of membranes. It was noted that the flux decrements of S-SMP (SMP in SSBWR-MBR) with cellulose acetate (CA), polyvinylidene fluoride (PVDF) and polyether sulfones (PES) membranes were respectively 6.7%, 8.5% and 9.5% lower compared to those of C-SMP (SMP in Control-MBR) with corresponding membranes. However, for both the filtration of the C-SMP and S-SMP, the CA membrane exhibited the fastest diminishing rate of flux among the three types of membranes. The surface morphology analysis showed that the CA membrane exhibited more but smaller protuberances compared to the PVDF and PES. The second minimums surrounding each protruding asperity on CA membrane were more than those on the PVDF and PES membranes, enhancing the attachment of SMP onto the membrane surface.

  4. Membrane distillation combined with an anaerobic moving bed biofilm reactor for treating municipal wastewater.

    PubMed

    Kim, Hyun-Chul; Shin, Jaewon; Won, Seyeon; Lee, Jung-Yeol; Maeng, Sung Kyu; Song, Kyung Guen

    2015-03-15

    A fermentative strategy with an anaerobic moving bed biofilm reactor (AMBBR) was used for the treatment of domestic wastewater. The feasibility of using a membrane separation technique for post-treatment of anaerobic bio-effluent was evaluated with emphasis on employing a membrane distillation (MD). Three different hydrophobic 0.2 μm membranes made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polypropylene (PP) were examined in this study. The initial permeate flux of the membranes ranged from 2.5 to 6.3 L m(-2) h(-1) when treating AMBBR effluent at a temperature difference between the feed and permeate streams of 20 °C, with the permeate flux increasing in the order PP < PVDF < PTFE. The permeate flux of the PTFE membrane gradually decreased to 84% of the initial flux after the 45 h run for distillation, while a flux decline in MD with either the PVDF or PP membrane was not found under the identical distillation conditions. During long-term distillation with the PVDF membrane, total phosphorus was completely rejected and >98% rejection of dissolved organic carbon was also achieved. The characterization of wastewater effluent organic matter (EfOM) using an innovative suite of analytical tools verified that almost all of the EfOM was rejected via the PVDF MD treatment.

  5. Improvement of antifouling characteristics in a bioreactor of polypropylene microporous membrane by the adsorption of Tween 20.

    PubMed

    Xie, Ya-jie; Yu, Hai-yin; Wang, Shu-yuan; Xu, Zhi-kang

    2007-01-01

    Surface modification by physical adsorption of Tween 20 was accomplished on polypropylene microporous membranes (PPMMs). Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR) and field emission scanning electron microscope (FE-SEM) were used to characterize the chemical and morphological changes on the membrane surfaces. Water contact angles and relative pure water fluxes were measured. The data showed that the hydrophilic performance for the modified membranes increased with the increase in the adsorption amount of Tween 20 onto the surface or into the pores of polypropylene microporous membranes. To test the antifouling property of the membranes by the adsorption of Tween 20 in a membrane bioreactor (MBR), filtration for active sludge was performed using synthetic wastewater. With the help of the data of water fluxes and the FE-SEM photos of the modified PPMMs before or after operating in a MBR for about 12 d, the PPMMs with monolayer adsorption of Tween 20 showed higher remained flux and stronger antifouling ability than unmodified membrane and other modification membranes studied.

  6. Evaluation of the importance of various operating and sludge property parameters to the fouling of membrane bioreactors.

    PubMed

    Sun, F Y; Li, X Y

    2011-01-01

    A single-fibre microfiltration system was employed to investigate the importance of various operating and sludge property parameters to the membrane fouling during sludge filtration. The sludge was obtained from a submerged membrane bioreactor (SMBR). A series of comparative and correlative filtration and fouling tests were conducted on the influence of the operating variables, sludge properties and the liquid-phase organic substances on the membrane fouling development. The test results were analysed statistically with Pearson's correlation coefficients and the stepwise multivariable linear regression. According to the statistical evaluation, the membrane fouling rate has a positive correlation with the biopolymer cluster (BPC) concentration, sludge concentration (mixed liquor suspended solids, MLSS), filtration flux and viscosity, a negative correlation with the cross-flow velocity, and a weak correlation with the extracellular polymeric substances and soluble microbial products. BPC appear to be the most important factor to membrane fouling development during the sludge filtration, followed by the filtration flux and MLSS concentration. The cross-flow rate also is important to the fouling control. It is argued that, during membrane filtration of SMBR sludge, BPC interact with sludge flocs at the membrane surface to facilitate the deposition of the sludge cake layer, leading to serious membrane fouling.

  7. Sulfur-based mixotrophic denitrification corresponding to different electron donors and microbial profiling in anoxic fluidized-bed membrane bioreactors.

    PubMed

    Zhang, Lili; Zhang, Chao; Hu, Chengzhi; Liu, Huijuan; Bai, Yaohui; Qu, Jiuhui

    2015-11-15

    Sulfur-based mixotrophic denitrifying anoxic fluidized bed membrane bioreactors (AnFB-MBR) were developed for the treatment of nitrate-contaminated groundwater with minimized sulfate production. The nitrate removal rates obtained in the methanol- and ethanol-fed mixotrophic denitrifying AnFB-MBRs reached 1.44-3.84 g NO3 -N/L reactor d at a hydraulic retention time of 0.5 h, which were significantly superior to those reported in packed bed reactors. Compared to methanol, ethanol was found to be a more effective external carbon source for sulfur-based mixotrophic denitrification due to lower sulfate and total organic carbon concentrations in the effluent. Using pyrosequencing, the phylotypes of primary microbial groups in the reactor, including sulfur-oxidizing autotrophic denitrifiers, methanol- or ethanol-supported heterotrophic denitrifiers, were investigated in response to changes in electron donors. Principal component and heatmap analyses indicated that selection of electron donating substrates largely determined the microbial community structure. The abundance of Thiobacillus decreased from 45.1% in the sulfur-oxidizing autotrophic denitrifying reactor to 12.0% and 14.2% in sulfur-based methanol- and ethanol-fed mixotrophic denitrifying bioreactors, respectively. Heterotrophic Methyloversatilis and Thauera bacteria became more dominant in the mixotrophic denitrifying bioreactors, which were possibly responsible for the observed methanol- and ethanol-associated denitrification.

  8. The effect of biomass immobilization support material and bed porosity on hydrogen production in an upflow anaerobic packed-bed bioreactor.

    PubMed

    Fernandes, B S; Saavedra, N K; Maintinguer, S I; Sette, L D; Oliveira, V M; Varesche, M B A; Zaiat, M

    2013-07-01

    The aim of this study was to investigate the effect of the support material used for biomass attachment and bed porosity on the potential generation of hydrogen gas in an anaerobic bioreactor treating low-strength wastewater. For this purpose, an upflow anaerobic packed-bed (UAPB) reactor fed with sucrose-based synthetic wastewater was used. Three reactors with various support materials (expanded clay, vegetal coal, and low-density polyethylene) were operated for hydraulic retention time (HRT) of 0.5 and 2 h. Based on the results obtained, three further reactors were operated with low-density polyethylene as a material support using various bed porosities (91, 75, and 50 %) for an HRT of 0.5 h. The UAPB reactor was found to be a feasible technology for hydrogen production, reaching a maximum substrate-based hydrogen yield of 7 mol H₂ mol(-1) sucrose for an HRT of 0.5 h. The type of support material used did not affect hydrogen production or the microbial population inside the reactor. Increasing the bed porosity to 91 % provided a continuous and cyclic production of hydrogen, whereas the lower bed porosities resulted in a reduced time of hydrogen production due to biomass accumulation, which resulted in a decreasing working volume.

  9. Ethanol fermentation kinetics in a continuous and closed-circulating fermentation system with a pervaporation membrane bioreactor.

    PubMed

    Chen, Chunyan; Tang, Xiaoyu; Xiao, Zeyi; Zhou, Yihui; Jiang, Yue; Fu, Shengwei

    2012-06-01

    The kinetics of ethanol fermentation by Saccharomyces cerevisiae was studied in a continuous and closed-circulating fermentation (CCCF) system with a polydimethylsiloxane (PDMS) pervaporation membrane bioreactor. Three sequential 500-h cycles of CCCF experiments were carried out. A glucose volumetric consumption of 3.8 g L(-1) h(-1) and ethanol volumetric productivity of 1.39 g L(-1) h(-1) were obtained in the third cycle, with a specific glucose utilization rate of 0.32 h(-1) and ethanol yield rate of 0.13 h(-1). The prolonged fermentation time and good fermentation performance indicate that the CCCF would be a feasible and promising fermentation process technology.

  10. Fiber Attachment Module Experiment (FAME): Using a Multiplexed Miniature Hollow Fiber Membrane Bioreactor Solution for Rapid Process Testing

    NASA Astrophysics Data System (ADS)

    Lunn, Griffin; Wheeler, Raymond; Hummerick, Mary; Birmele, Michele; Richards, Jeffrey; Coutts, Janelle; Koss, Lawrence; Spencer, Lashelle.; Johnsey, Marissa; Ellis, Ronald

    Bioreactor research, even today, is mostly limited to continuous stirred-tank reactors (CSTRs). These are not an option for microgravity applications due to the lack of a gravity gradient to drive aeration as described by the Archimedes principle. This has led to testing of Hollow Fiber Membrane Bioreactors (HFMBs) for microgravity applications, including possible use for wastewater treatment systems for the International Space Station (ISS). Bioreactors and filtration systems for treating wastewater could avoid the need for harsh pretreatment chemicals and improve overall water recovery. However, the construction of these reactors is difficult and commercial off-the-shelf (COTS) versions do not exist in small sizes. We have used 1-L modular HFMBs in the past, but the need to perform rapid testing has led us to consider even smaller systems. To address this, we designed and built 125-mL, rectangular reactors, which we have called the Fiber Attachment Module Experiment (FAME) system. A polycarbonate rack of four square modules was developed with each module containing removable hollow fibers. Each FAME reactor is self-contained and can be easily plumbed with peristaltic and syringe pumps for continuous recycling of fluids and feeding, as well as fitted with sensors for monitoring pH, dissolved oxygen, and gas measurements similar to their larger counterparts. The first application tested in the FAME racks allowed analysis of over a dozen fiber surface treatments and three inoculation sources to achieve rapid reactor startup and biofilm attachment (based on carbon oxidation and nitrification of wastewater). With these miniature FAME reactors, data for this multi-factorial test were collected in duplicate over a six-month period; this greatly compressed time period required for gathering data needed to study and improve bioreactor performance.

  11. Start-up of the SHARON and ANAMMOX process in landfill bioreactors using aerobic and anaerobic ammonium oxidising biomass.

    PubMed

    Shalini, S Sri; Joseph, Kurian

    2013-12-01

    The main aim of this study is to analyse the feasibility to use aerobic ammonium oxidising bacteria (AOB) and anammox/AnAOB biomass enriched from mined municipal solid waste for in situ SHARON and ANAMMOX processes in laboratory scale landfill bioreactors (LFBR) for ammonia nitrogen removal. For this purpose, three LFBRs were operated as Control (without biomass seed), SHARON (with AOB biomass seed) and ANAMMOX (with anammox biomass seed) for 315 days. Results showed nitrogen loading rate of 1.0 kg N/d was effectively removed in SHARON and ANAMMOX LFBR. In SHARON LFBR, partial nitritation efficiency reached up to 98.5% with AOB population of MPN of 5.1 × 10(6)/mL obtained. ANAMMOX LFBR gave evolution of 95% of nitrogen gas as the end product confirmed the ANAMMOX process. Nitrogen transformations, biomass development and hydrazine and hydroxylamine formation authenticated the enriched AOB and anammox biomass activity in landfill bioreactors.

  12. A novel membrane bioreactor for detoxifying industrial wastewater. 1. Biodegradation of phenol in a synthetically concocted wastewater

    SciTech Connect

    Livingston, A.G. )

    1993-04-25

    A novel process has been used to biodegrade phenol present in acidic and salty synthetically concocted wastewater. The process utilizes a membrane bioreactor, in which the phenol present in the wastewater is separated from the inorganic components by means of a silicone rubber membrane. Transfer of the phenol from the wastewater and into a biological growth medium allows biodegradation to proceed under controlled conditions which are unaffected by the hostile inorganic composition of the wastewater. At a wastewater flow rate of 18 mL h[sup [minus]1], 98.5% of the phenol present in the wastewater at an inlet concentration of 1,000 mg L[sup [minus]1] was degraded; at a contact time of 1.9 h, 65% of the phenol was degraded. Phenol degradation was accompanied by growth of a biofilm on the membrane tubes and by conversion of approximately 80% of the carbon entering the system to CO[sub 2] carbon. Analysis of the transport of phenol across the membrane revealed that the major resistance to mass transfer arose in the diffusion of phenol across the silicon rubber membrane. A mathematical model was used to describe the transfer of phenol across the membrane and the subsequent diffusion and reaction of phenol in the biofilm attached to the membrane tube.

  13. Chemical Characterization of Low Molecular Weight Soluble Microbial Products in an Anaerobic Membrane Bioreactor.

    PubMed

    Kunacheva, Chinagarn; Le, Chencheng; Soh, Yan Ni Annie; Stuckey, David C

    2017-02-21

    Effluents from wastewater treatment systems contain a variety of organic compounds, including end products from the degradation of influent substrates, nonbiodegradable feed compounds, and soluble microbial products (SMPs) produced by microbial metabolism. It is important to identify the major components of these SMPs to understand what is in wastewater effluents. In this study, physical pretreatments to extract and concentrate low molecular weight SMPs (MW< 580 Da) from effluents were optimized. Liquid-liquid extraction (LLE) of a 200 mL effluent sample showed the best performance using a mixture of n-hexane, chloroform, and dichloromethane (70 mL) for extraction. For solid phase extraction (SPE), two OasisHLB cartridges were connected in-line to optimize recovery, and the eluted samples from each cartridge were analyzed separately to avoid overlapping peaks. Four solvents varying from polar to nonpolar (methanol, acetone, dichloromethane, and n-hexane) were selected to maximize the number of compound peaks eluted. A combination of SPE (OasisHLB) followed by LLE was shown to maximize compound identification and quantification. However, the compounds identified accounted for only 2.1 mg of chemical oxygen demand (COD)/L (16% of total SMP as COD) because many SMPs have considerably higher MWs. Finally, the method was validated by analyzing a variety of different reactor effluents and feeds.

  14. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    NASA Astrophysics Data System (ADS)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  15. Long-term evaluation of different strategies of cationic polyelectrolyte dosage to control fouling in a membrane bioreactor treating refinery effluent.

    PubMed

    Alkmim, Aline R; da Costa, Paula R; Moser, Priscila B; França Neta, Luzia S; Santiago, Vânia M J; Cerqueira, Ana C; Amaral, Míriam C S

    2016-01-01

    In this article, the long-term use of cationic polyelectrolyte to improve the sludge filterability and to control membrane fouling in bioreactor membrane while treating refinery effluents have been evaluated in pilot scale. Corrective and preventive cationic polyelectrolyte dosages have been added to the membrane bioreactor (MBR) to evaluate the membrane fouling mitigation in both strategies. The results have confirmed that the use of the Membrane performance enhancer (MPE) increased the sludge filterability and reduced the membrane fouling. During the monitoring period, stress events occurred due to the increase in oil and grease and phenol concentrations in the MBR feeds. The preventive use of cationic polyelectrolyte allowed for a more effective and stable sludge filterability, with lower cationic polyelectrolyte consumption and without decreasing MBR's overall pollutant removal performance.

  16. The major anaerobically induced outer membrane protein of Neisseria gonorrhoeae, Pan 1, is a lipoprotein.

    PubMed Central

    Hoehn, G T; Clark, V L

    1992-01-01

    Pan 1 is an acidic outer membrane protein of Neisseria gonorrhoeae that is expressed only when gonococci are grown anaerobically. On silver-stained sodium dodecyl sulfate-polyacrylamide gels, Pan 1 migrates as an intense but diffuse 54-kDa protein. The deduced amino acid sequence of Pan 1 from the aniA (anaerobically induced protein) open reading frame reveals a lipoprotein consensus sequence, Ala-Leu-Ala-Ala-Cys, and a processed molecular mass of 39 kDa. Furthermore, there is strong homology at the N terminus and C terminus of Pan 1 to the termini of the gonococcal outer membrane lipoproteins Lip and Laz. [3H]palmitic acid labeling of gonococci grown under oxygen-limited conditions demonstrated specific incorporation of label into Pan 1, suggesting further that Pan 1 is a lipoprotein. Images PMID:1398981

  17. Direct and complete phosphorus recovery from municipal wastewater using a hybrid microfiltration-forward osmosis membrane bioreactor process with seawater brine as draw solution.

    PubMed

    Qiu, Guanglei; Law, Yi-Ming; Das, Subhabrata; Ting, Yen-Peng

    2015-05-19

    We report a hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) for direct phosphorus recovery from municipal wastewater in the course of its treatment. In the process, a forward osmosis (FO) membrane and a microfiltration (MF) membrane are operated in parallel in a bioreactor. FO membrane rejects the nutrients (e.g., PO4(3-), Ca(2+), Mg(2+), etc.) and results in their enrichment in the bioreactor. The nutrients are subsequently extracted via the MF membrane. Phosphorus is then recovered from the nutrients enriched MF permeate via precipitation without addition of an external source of calcium or magnesium. The use of seawater brine as a draw solution (DS) is another novel aspect of the system. The process achieved 90% removal of total organic carbon and 99% removal of NH4(+)-N. 97.9% of phosphate phosphorus (PO4(3-)-P) was rejected by the FO membrane and enriched within the bioreactor. >90% phosphorus recovery was achieved at pH 9.0. The precipitates were predominantly amorphous calcium phosphate with a phosphorus content of 11.1-13.3%. In principal, this process can recover almost all the phosphorus, apart from that assimilated by bacteria for growth. Global evaluation showed an overall phosphorus recovery of 71.7% over 98 days.

  18. Effects of carriers on nutrient removal and membrane fouling in combined process of inclined-plates hydrolytic tank and membrane bioreactor.

    PubMed

    Li, Xin; Liu, Yali; Chu, Mingxing; Liu, Aimin

    2016-11-01

    A novel process, inclined-plates hydrolytic tank (IHT) and membrane bioreactor (MBR), was used to treat domestic sewage continuously. In this study, the effects of carriers' addition on operational performances of IHT-MBR were studied at the hydraulic retention time of 5.4 h and the recycling rate of 200%. Experimental results indicated the removal efficiencies of chemical oxygen demand, total nitrogen and total phosphorus reached 86.8%, 82.9% and 89.6%, respectively, corresponding trans-membrane pressure decreased to 1.50 kPa/d at a packing ratio of 20%. Simultaneously, the scanning electron microscope and soluble microbial products analysis demonstrated that high nutrient removal and low membrane fouling were attributed to the attached growth of microorganisms on carriers. The bioattachment and adsorption of carriers not only decreased the soluble proteins and polysaccharide in MBR, but also provided good living environments for denitrifying bacteria and phosphorus-accumulating bacteria.

  19. Nitrification performance and microbial community dynamics in a submerged membrane bioreactor with complete sludge retention.

    PubMed

    Li, Hongyan; Yang, Min; Zhang, Yu; Yu, Tao; Kamagata, Yoichi

    2006-05-03

    A submerged membrane bioreactor (MBR) supplied with inorganic ammonium-bearing wastewater (NH(4)(+)-N, 500 mgl(-1)) was operated for 260 days without sludge purge under decreased hydraulic retention times (HRT) through six steps (from 30 to 5h). Almost complete nitrification was obtained at a volumetric loading rate (VLR)1.2g NH(4)(+)-Nl(-1)day(-1). The sludge nitrification activities were evaluated at each stage. The specific ammonium oxidizing rate (SAOR) decreased from the initial 0.45 to 0.15 kg NH(4)(+)-Nkg(-1)MLSSday(-1) in the last four stages, while the specific nitrate forming rate (SNFR) increased from 0.17 to 0.39 kg NO(3)(-)-Nkg(-1)MLSSday(-1) at the third stage, and then decreased to below 0.1 kg NO(3)(-)-Nkg(-1)MLSSday(-1) from the fourth stage. Microbial population dynamics was investigated by a combination of the MPN method, fluorescence in situ hybridization (FISH) and quinone profiles. During the experiment, although the MLSS increased gradually from 4.5 to 11.5 gl(-1), the number of ammonia-oxidizing bacteria (AOB) decreased from 10(9)l(-1) at the third stage to 10(7)l(-1) in the last two stages, and that of nitrite-oxidizing bacteria (NOB) decreased gradually from 10(8)l(-1) at the second stage (HRT of 20 h) to the final 10(5)l(-1). FISH results showed that the active cells decreased gradually with time from about 60 to 20% in the last two stages, and most of sludge was inert cells. The sum of nitrifiers occupied only about 10% of the total bacteria number in the last stage even though only ammonium-bearing inorganic wastewater was fed in. Nitrosomonas sp. and Nitrospira sp. were confirmed by FISH as the dominant nitrifying genera responsible for ammonia and nitrite oxidation, respectively. In the mean time, a small ratio of Nitrobacter sp. also existed in the system. FISH analysis matched better with the batch activity test results than did the MPN techniques. Quinone profiles revealed that the dominant ubiquinone was ubiquinone-8 (UQ-8

  20. Continuous co-production of ethanol and xylitol from rice straw hydrolysate in a membrane bioreactor.

    PubMed

    Zahed, Omid; Jouzani, Gholamreza Salehi; Abbasalizadeh, Saeed; Khodaiyan, Faramarz; Tabatabaei, Meisam

    2016-05-01

    The present study was set to develop a robust and economic biorefinery process for continuous co-production of ethanol and xylitol from rice straw in a membrane bioreactor. Acid pretreatment, enzymatic hydrolysis, detoxification, yeast strains selection, single and co-culture batch fermentation, and finally continuous co-fermentation were optimized. The combination of diluted acid pretreatment (3.5 %) and enzymatic conversion (1:10 enzyme (63 floating-point unit (FPU)/mL)/biomass ratio) resulted in the maximum sugar yield (81 % conversion). By concentrating the hydrolysates, sugars level increased by threefold while that of furfural reduced by 50 % (0.56 to 0.28 g/L). Combined application of active carbon and resin led to complete removal of furfural, hydroxyl methyl furfural, and acetic acid. The strains Saccharomyces cerevisiae NCIM 3090 with 66.4 g/L ethanol production and Candida tropicalis NCIM 3119 with 9.9 g/L xylitol production were selected. The maximum concentrations of ethanol and xylitol in the single cultures were recorded at 31.5 g/L (0.42 g/g yield) and 26.5 g/L (0.58 g/g yield), respectively. In the batch co-culture system, the ethanol and xylitol productions were 33.4 g/L (0.44 g/g yield) and 25.1 g/L (0.55 g/g yield), respectively. The maximum ethanol and xylitol volumetric productivity values in the batch co-culture system were 65 and 58 % after 25 and 60 h, but were improved in the continuous co-culture mode and reached 80 % (55 g/L) and 68 % (31 g/L) at the dilution rate of 0.03 L per hour, respectively. Hence, the continuous co-production strategy developed in this study could be recommended for producing value-added products from this hugely generated lignocellulosic waste.