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Sample records for bed membrane bioreactor

  1. Start-up of membrane bioreactor and hybrid moving bed biofilm reactor-membrane bioreactor: kinetic study.

    Science.gov (United States)

    Leyva-Díaz, J C; Poyatos, J M

    2015-01-01

    A hybrid moving bed biofilm reactor-membrane bioreactor (hybrid MBBR-MBR) system was studied as an alternative solution to conventional activated sludge processes and membrane bioreactors. This paper shows the results obtained from three laboratory-scale wastewater treatment plants working in parallel in the start-up and steady states. The first wastewater treatment plant was a MBR, the second one was a hybrid MBBR-MBR system containing carriers both in anoxic and aerobic zones of the bioreactor (hybrid MBBR-MBRa), and the last one was a hybrid MBBR-MBR system which contained carriers only in the aerobic zone (hybrid MBBR-MBRb). The reactors operated with a hydraulic retention time of 30.40 h. A kinetic study for characterizing heterotrophic biomass was carried out and organic matter and nutrients removals were evaluated. The heterotrophic biomass of the hybrid MBBR-MBRb showed the best kinetic performance in the steady state, with yield coefficient for heterotrophic biomass=0.30246 mg volatile suspended solids per mg chemical oxygen demand, maximum specific growth rate for heterotrophic biomass=0.00308 h(-1) and half-saturation coefficient for organic matter=3.54908 mg O2 L(-1). The removal of organic matter was supported by the kinetic study of heterotrophic biomass.

  2. An aerated and fluidized bed membrane bioreactor for effective wastewater treatment with low membrane fouling

    KAUST Repository

    Ye, Yaoli

    2016-09-24

    Anaerobic fluidized bed membrane bioreactors (AFMBRs) use granular activated carbon (GAC) particles suspended by recirculation to effectively treat low strength wastewaters (∼100–200 mg L−1, chemical oxygen demand, COD), but the effluent can contain dissolved methane. An aerobic fluidized bed membrane bioreactor (AOFMBR) was developed to avoid methane production and the need for wastewater recirculation by using rising air bubbles to suspend GAC particles. The performance of the AOFMBR was compared to an AFMBR and a conventional aerobic membrane bioreactor (AeMBR) for domestic wastewater treatment over 130 d at ambient temperatures (fixed hydraulic retention time of 1.3 h). The effluent of the AOFMBR had a COD of 20 ± 8 mg L−1, and a turbidity of <0.2 NTU, for low-COD influent (153 ± 19 and 214 ± 27 mg L−1), similar to the AeMBR and AFMBR. For the high-COD influent (299 ± 24 mg L−1), higher effluent CODs were obtained for the AeMBR (38 ± 9 mg L−1) and AFMBR (51 ± 11 mg L−1) than the AOFMBR (26 ± 6 mg L−1). Transmembrane pressure of the AOFMBR increased at 0.04 kPa d−1, which was 20% less than the AeMBR and 57% less than the AFMBR, at the low influent COD. Scanning electron microscopy (SEM) analysis indicated a more uniform biofilm on the membrane in AOFMBR than that from the AeMBR biofilm, and no evidence of membrane damage. High similarity was found between communities in the suspended sludge in the AOFMBR and AeMBR (square-root transformed Bray–Curtis similarity, SRBCS, 0.69). Communities on the GAC and suspended sludge were dissimilar in the AOFMBR (SRBCS, 0.52), but clustered in the AFMBR (SRBCS, 0.63).

  3. Tapered bed bioreactor

    Science.gov (United States)

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  4. Start-up of two moving bed membrane bioreactors treating saline wastewater contaminated by hydrocarbons.

    Science.gov (United States)

    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.

  5. Membrane fouling mitigation in a moving bed membrane bioreactor combined with anoxic biofilter for treatment of saline wastewater from mariculture.

    Science.gov (United States)

    Song, Weilong; You, Hong; Li, Zhipeng; Liu, Feng; Qi, Peishi; Wang, Fang; Li, Yizhu

    2017-07-18

    Membrane fouling mitigation in a novel AF-MBMBR system (moving bed membrane bioreactor (10L) coupled with anoxic biofilter (4L)) under high salinity condition (35‰) was systematically investigated. Pre-positioned AF served as a pretreatment induced significant decrease of suspended biomass by 85% and dissolved organic matters by 51.7% in subsequent MBR, which resulted in a reduction of cake layer formation. Based on this, sponge bio-carriers in MBMBR further alleviated the fouling propensity by modifying extracellular polymeric substances (EPS) properties. The protein component in EPS decreased from 181.4 to 116.5mg/g MLSS, with a decline of protein/carbohydrate ratio from 4.6 to 3.4. In particular, elimination of hydrophobic groups like aromatic protein-like substance in EPS was detected. These caused the less biomass deposition on membrane surface, thereby alleviating membrane fouling. In summary, mitigation of membrane fouling in AF-MBMBR should be attributed to contributions from both pre-positioned AF and sponge bio-carriers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Comparative study on membrane fouling between membrane-coupled moving bed biofilm reactor and conventional membrane bioreactor for municipal wastewater treatment.

    Science.gov (United States)

    Yang, W; Syed, W; Zhou, H

    2014-01-01

    This study compared the performance between membrane-coupled moving bed biofilm reactor (M-MBBR) and a conventional membrane bioreactor (MBR) in parallel. Extensive tests were conducted in three pilot-scale experimental units over 6 months. Emphasis was placed on the factors that would affect the performance of membrane filtration. The results showed that the concentrations of soluble microbial product (SMP), colloidal total organic carbon and transparent exopolymer particles in the M-MBBR systems were not significantly different from those in the control MBR system. However, the fouling rates were much higher in the M-MBBR systems as compared to the conventional MBR systems. This indicates membrane fouling potential was related not only to the concentration of SMP, but also to their sources and characteristics. The addition of polyaluminum chloride could reduce the fouling rate of the moving bed biofilm reactor unit by 56.4-84.5% at various membrane fluxes.

  7. Impact of acclimation methods on microbial communities and performance of anaerobic fluidized bed membrane bioreactors

    KAUST Repository

    Labarge, Nicole

    2016-10-17

    An anaerobic fluidized bed membrane bioreactor (AFMBR) is a new and effective method for energy-efficient treatment of low strength wastewater, but the factors that affect performance are not well known. Different inocula and acclimation methods of the granular activated carbon (GAC) used in the reactor were examined here to determine their impact on chemical oxygen demand (COD) removal and microbial community composition of domestic wastewater-fed AFMBRs. AFMBRs inoculated with anaerobic digester sludge (D) or domestic wastewater (W) and fed domestic wastewater, or inoculated with a microbiologically diverse anaerobic bog sediment and acclimated using methanol (M), all produced the same COD removal of 63 ± 12% using a diluted wastewater feed (100 ± 21 mg L−1 COD). However, an AFMBR with GAC inoculated with anaerobic digester sludge and acclimated using acetate (A) showed significantly increased wastewater COD removal to 84 ± 6%. In addition, feeding the AFMBR with the M-acclimated GAC with an acetate medium for one week subsequently increased COD removal to 70 ± 6%. Microbial communities enriched on the GAC included Geobacter, sulfur-reducing bacteria, Syntrophaceae, and Chlorobiaceae, with reactor A having the highest relative abundance of Geobacter. These results showed that acetate was the most useful substrate for acclimation of GAC communities, and GAC harbors unique communities relative to those in the AFMBR influent and recirculated solution.

  8. The characteristics of extracellular polymeric substances and soluble microbial products in moving bed biofilm reactor-membrane bioreactor.

    Science.gov (United States)

    Duan, Liang; Jiang, Wei; Song, Yonghui; Xia, Siqing; Hermanowicz, Slawomir W

    2013-11-01

    The characteristics of extracellular polymeric substances (EPS) and soluble microbial products (SMP) in conventional membrane bioreactor (MBR) and in moving bed biofilm reactor-membrane bioreactors (MBBR-MBR) were investigated in long-term (170 days) experiments. The results showed that all reactors had high removal efficiency of ammonium and COD, despite very different fouling conditions. The MBBR-MBR with media fill ratio of 26.7% had much lower total membrane resistance and no obvious fouling were detected during the whole operation. In contrast, MBR and MBBR-MBR with lower and higher media fill experienced more significant fouling. Low fouling at optimum fill ratio may be due to the higher percentage of small molecular size (100 kDa) of EPS and SMP in the reactor. The composition of EPS and SMP affected fouling due to different O-H bonds in hydroxyl functional groups, and less polysaccharides and lipids.

  9. New functional biocarriers for enhancing the performance of a hybrid moving bed biofilm reactor-membrane bioreactor system.

    Science.gov (United States)

    Deng, Lijuan; Guo, Wenshan; Ngo, Huu Hao; Zhang, Xinbo; Wang, Xiaochang C; Zhang, Qionghua; Chen, Rong

    2016-05-01

    In this study, new sponge modified plastic carriers for moving bed biofilm reactor (MBBR) was developed. The performance and membrane fouling behavior of a hybrid MBBR-membrane bioreactor (MBBR-MBR) system were also evaluated. Comparing to the MBBR with plastic carriers (MBBR), the MBBR with sponge modified biocarriers (S-MBBR) showed better effluent quality and enhanced nutrient removal at HRTs of 12h and 6h. Regarding fouling issue of the hybrid systems, soluble microbial products (SMP) of the MBR unit greatly influenced membrane fouling. The sponge modified biocarriers could lower the levels of SMP in mixed liquor and extracellular polymeric substances in activated sludge, thereby mitigating cake layer and pore blocking resistances of the membrane. The reduced SMP and biopolymer clusters in membrane cake layer were also observed. The results demonstrated that the sponge modified biocarriers were capable of improving overall MBBR performance and substantially alleviated membrane fouling of the subsequent MBR unit.

  10. Sulfur-based mixotrophic denitrification corresponding to different electron donors and microbial profiling in anoxic fluidized-bed membrane bioreactors.

    Science.gov (United States)

    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.

  11. Evaluation of micropollutant removal and fouling reduction in a hybrid moving bed biofilm reactor-membrane bioreactor system.

    Science.gov (United States)

    Luo, Yunlong; Jiang, Qi; Ngo, Huu H; Nghiem, Long D; Hai, Faisal I; Price, William E; Wang, Jie; Guo, Wenshan

    2015-09-01

    A hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system and a conventional membrane bioreactor (CMBR) were compared in terms of micropollutant removal efficiency and membrane fouling propensity. The results show that the hybrid MBBR-MBR system could effectively remove most of the selected micropollutants. By contrast, the CMBR system showed lower removals of ketoprofen, carbamazepine, primidone, bisphenol A and estriol by 16.2%, 30.1%, 31.9%, 34.5%, and 39.9%, respectively. Mass balance calculations suggest that biological degradation was the primary removal mechanism in the MBBR-MBR system. During operation, the MBBR-MBR system exhibited significantly slower fouling development as compared to the CMBR system, which could be ascribed to the wide disparity in the soluble microbial products (SMP) levels between MBBR-MBR (4.02-6.32 mg/L) and CMBR (21.78 and 33.04 mg/L). It is evident that adding an MBBR process prior to MBR treatment can not only enhance micropollutant elimination but also mitigate membrane fouling.

  12. Essential factors of an integrated moving bed biofilm reactor-membrane bioreactor: Adhesion characteristics and microbial community of the biofilm.

    Science.gov (United States)

    Tang, Bing; Yu, Chunfei; Bin, Liying; Zhao, Yiliang; Feng, Xianfeng; Huang, Shaosong; Fu, Fenglian; Ding, Jiewei; Chen, Cuiqun; Li, Ping; Chen, Qianyu

    2016-07-01

    This work aims at revealing the adhesion characteristics and microbial community of the biofilm in an integrated moving bed biofilm reactor-membrane bioreactor, and further evaluating their variations over time. With multiple methods, the adhesion characteristics and microbial community of the biofilm on the carriers were comprehensively illuminated, which showed their dynamic variation along with the operational time. Results indicated that: (1) the roughness of biofilm on the carriers increased very quickly to a maximum value at the start-up stage, then, decreased to become a flat curve, which indicated a layer of smooth biofilm formed on the surface; (2) the tightly-bound protein and polysaccharide was the most important factor influencing the stability of biofilm; (3) the development of biofilm could be divided into three stages, and Gammaproteobacteria were the most dominant microbial species in class level at the last stage, which occupied the largest ratio (51.48%) among all microbes.

  13. Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Yousef, E-mail: yrahimi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Torabian, Ali, E-mail: atorabi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Mehrdadi, Naser, E-mail: mehrdadi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Habibi-Rezaie, Mehran, E-mail: mhabibi@khayam.ut.ac.ir [Department of Biotechnology, Faculty of Biology, College of Science, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Pezeshk, Hamid, E-mail: pezeshk@khayam.ut.ac.ir [Department of Statistics, Faculty of Mathematics and Computer, College of Science, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Nabi-Bidhendi, Gholam-Reza, E-mail: ghhendi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of)

    2011-02-28

    Research highlights: {yields} There is an optimum aeration rate in the MBMBR process compartments. {yields} Optimum aeration rate maximizes nutrients removal. {yields} Optimum aeration rate minimizes membrane fouling. {yields} Both aeration rates in MBBR and membrane compartment can affect on membrane permeability. - Abstract: In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h{sup -1} and a specific aeration demand per membrane area (SAD{sub m}) of 1.2 and 0.4m{sub air}{sup 3} m{sup -2} h{sup -1}, respectively. A linear correlation was found between the amount of attached biofilm and the nutrient removal rate. The aeration rate in the MBBR compartment and SAD{sub m} significantly influenced the sludge characteristics and membrane permeability. The optimum combination of the aeration rate in the MBBR compartment and SAD{sub m} were 151 L h{sup -1} and 0.8-1.2m{sub air}{sup 3}m{sub membrane}{sup -2} h{sup -1}, respectively.

  14. An Innovative membrane bioreactor and packed-bed biofilm reactor combined system for shortcut nitrification-denitrification

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yunxia; ZHOU Jiti; ZHANG Jinsong; YUAN Shouzhi

    2009-01-01

    An innovative shortcut biological nitrogen removal system, consisting of an aerobic submerged membrane bioreactor (MBR) and an anaerobic packed-bed biofilm reactor (PBBR), was evaluated for treating high strength ammonium-bearing wastewater. The system was seeded with enriched ammonia-oxidizing bacteria (AOB) and operated without sludge purge with a decreased hydraulic retention time (HRT) through three phases. The MBR was successful in both maintaining nitrite ratio over 0.95 and nitrification efficiency higher than 98% at a HRT of 24 h. The PBBR showed satisfactory denitrification efficiency with very low effluent nitrite and nitrate concentration (both below 3 mg/L). By examining the nitrification activity of microorganism, it was found that the specific ammonium oxidization rate (SAOR) increased from 0.17 to 0.51 g N/(g VSS·d) and then decreased to 0.22 g N/(g VSS·d) at the last phase, which resulted from the accumulation of extracellular polymers substances (EPS) and inert matters enwrapped around the zoogloea. In contrast, the average specific nitrite oxidization rate (SNOR) is 0.002 g N/(g VSS·d), only 1% of SAOR. Because very little Nitrobactor has been detected by fluorescence in situ hybridization (FISH), it is confirmed that the stability of high nitrite accumulation in MBR is caused by a large amount of AOB.

  15. Two-step nitrification in a pure moving bed biofilm reactor-membrane bioreactor for wastewater treatment: nitrifying and denitrifying microbial populations and kinetic modeling.

    Science.gov (United States)

    Leyva-Díaz, J C; González-Martínez, A; Muñío, M M; Poyatos, J M

    2015-12-01

    The moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) is a novel solution to conventional activated sludge processes and membrane bioreactors. In this study, a pure MBBR-MBR was studied. The pure MBBR-MBR mainly had attached biomass. The bioreactor operated with a hydraulic retention time (HRT) of 9.5 h. The kinetic parameters for heterotrophic and autotrophic biomasses, mainly nitrite-oxidizing bacteria (NOB), were evaluated. The analysis of the bacterial community structure of the ammonium-oxidizing bacteria (AOB), NOB, and denitrifying bacteria (DeNB) from the pure MBBR-MBR was carried out by means of pyrosequencing to detect and quantify the contribution of the nitrifying and denitrifying bacteria in the total bacterial community. The relative abundance of AOB, NOB, and DeNB were 5, 1, and 3%, respectively, in the mixed liquor suspended solids (MLSS), and these percentages were 18, 5, and 2%, respectively, in the biofilm density (BD) attached to carriers. The pure MBBR-MBR had a high efficiency of total nitrogen (TN) removal of 71.81±16.04%, which could reside in the different bacterial assemblages in the fixed biofilm on the carriers. In this regard, the kinetic parameters for autotrophic biomass had values of YA=2.3465 mg O2 mg N(-1), μm, A=0.7169 h(-1), and KNH=2.0748 mg NL(-1).

  16. Performance of a membrane-dialysis bioreactor with a radial-flow fixed bed for the cultivation of a hybridoma cell line.

    Science.gov (United States)

    Bohmann, A; Pörtner, R; Märkl, H

    1995-10-01

    A bioreactor system for the continuous cultivation of animal cells with a high potential for scale-up is presented. This reactor system consists of radial-flow fixed-bed units coupled with a dialysis module The dialysis membrane enables the supply of low-molecular-weight nutrients and removal of toxic metabolites, while high-molecular-weight nutrients and products (e.g., monoclonal antibodies) are retained and accumulated. This concept was investigated on the laboratory scale in a bioreactor with an integrated dialysis membrane. The efficiency of the reactor system and the reproducibility of the cell activity (hybridoma cells) under certain process conditions could be demonstrated in fermentations up to 77 days. Based on model calculations, an optimized fermentation strategy was formulated and experimentally confirmed. Compared to chemostat cultures with suspended cells, a ten-times higher mAb concentration (383 mg1(-1)) could be obtained. The highest volumetric specific mAb production rate determined was 6.1 mg mAb (1 fixed bed)-1h-1.

  17. Isolation and metagenomic characterization of bacteria associated with calcium carbonate and struvite precipitation in a pure moving bed biofilm reactor-membrane bioreactor.

    Science.gov (United States)

    Gonzalez-Martinez, A; Leyva-Díaz, J C; Rodriguez-Sanchez, A; Muñoz-Palazon, B; Rivadeneyra, A; Poyatos, J M; Rivadeneyra, M A; Martinez-Toledo, M V

    2015-01-01

    A bench-scale pure moving bed bioreactor-membrane bioreactor (MBBR-MBR) used for the treatment of urban wastewater was analyzed for the identification of bacterial strains with the potential capacity for calcium carbonate and struvite biomineral formation. Isolation of mineral-forming strains on calcium carbonate and struvite media revealed six major colonies with a carbonate or struvite precipitation capacity in the biofouling on the membrane surface and showed that heterotrophic bacteria with the ability to precipitate calcium carbonate and struvite constituted ~7.5% of the total platable bacteria. These belonged to the genera Lysinibacillus, Trichococcus, Comamomas and Bacillus. Pyrosequencing analysis of the microbial communities in the suspended cells and membrane biofouling showed a high degree of similarity in all the samples collected with respect to bacterial assemblage. The study of operational taxonomic units (OTUs) identified through pyrosequencing suggested that ~21% of the total bacterial community identified in the biofouling could potentially form calcium carbonate or struvite crystals in the pure MBBR-MBR system used for the treatment of urban wastewater.

  18. Anaerobic membrane bioreactors: Are membranes really necessary?

    NARCIS (Netherlands)

    Davila, M.; Kassab, G.; Klapwijk, A.; Lier, van J.B.

    2008-01-01

    Membranes themselves represent a significant cost for the full scale application of anaerobic membrane bioreactors (AnMBR). The possibility of operating an AnMBR with a self-forming dynamic membrane generated by the substances present in the reactor liquor would translate into an important saving. A

  19. Anaerobic membrane bioreactor under extreme conditions (poster)

    NARCIS (Netherlands)

    Munoz Sierra, J.D.; De Kreuk, M.K.; Spanjers, H.; Van Lier, J.B.

    2013-01-01

    Membrane bioreactors ensure biomass retention by the application of micro or ultrafiltration processes. This allows operation at high sludge concentrations. Previous studies have shown that anaerobic membrane bioreactors is an efficient way to retain specialist microorganisms for treating wastewater

  20. Application of acidogenic fixed-bed reactor prior to anaerobic membrane bioreactor for sustainable slaughterhouse wastewater treatment.

    Science.gov (United States)

    Saddoud, Ahlem; Sayadi, Sami

    2007-11-19

    High rate anaerobic treatment systems such as anaerobic membrane bioreactors (AMBR) are less popular for slaughterhouse wastewater due to the presence of high fat oil and suspended matters in the effluent. This affects the performance and efficiency of the treatment system. In this work, AMBR has been tried for slaughterhouse wastewater treatment. After the start up period, the reactor was operated with an average organic loading rate (OLR) of 4.37 kg TCODm(-3)d(-1) with gradual increase to an average of 13.27 kg TCODm(-3)d(-1). At stable conditions, the treatment efficiency was high with an average COD and BOD(5) reduction of 93.7 and 93.96%, respectively. However, a reduction in the AMBR performance was shown with the increase of the OLR to 16.32 kg TCODm(-3)d(-1). The removal efficiencies of SCOD and BOD(5) were drastically decreased to below 53.6 and 73.3%, respectively. The decrease of the AMBR performance was due to the accumulation of VFAs. Thus, a new integrated system composed of a FBR for the acidogenesis step followed by the AMBR for methanogenesis step was developed. At high ORL, the integrated system improved the performance of the anaerobic digestion and it successfully overcame the VFA accumulation problem in the AMBR. The anaerobic treatment led to a total removal of all tested pathogens. Thus, the microbiological quality of treated wastewater fits largely with WHO guidelines.

  1. Innovative sponge-based moving bed-osmotic membrane bioreactor hybrid system using a new class of draw solution for municipal wastewater treatment.

    Science.gov (United States)

    Nguyen, Nguyen Cong; Chen, Shiao-Shing; Nguyen, Hau Thi; Ray, Saikat Sinha; Ngo, Huu Hao; Guo, Wenshan; Lin, Po-Hsun

    2016-03-15

    For the first time, an innovative concept of combining sponge-based moving bed (SMB) and an osmotic membrane bioreactor (OsMBR), known as the SMB-OsMBR hybrid system, were investigated using Triton X-114 surfactant coupled with MgCl2 salt as the draw solution. Compared to traditional activated sludge OsMBR, the SMB-OsMBR system was able to remove more nutrients due to the thick-biofilm layer on sponge carriers. Subsequently less membrane fouling was observed during the wastewater treatment process. A water flux of 11.38 L/(m(2) h) and a negligible reverse salt flux were documented when deionized water served as the feed solution and a mixture of 1.5 M MgCl2 and 1.5 mM Triton X-114 was used as the draw solution. The SMB-OsMBR hybrid system indicated that a stable water flux of 10.5 L/(m(2) h) and low salt accumulation were achieved in a 90-day operation. Moreover, the nutrient removal efficiency of the proposed system was close to 100%, confirming the effectiveness of simultaneous nitrification and denitrification in the biofilm layer on sponge carriers. The overall performance of the SMB-OsMBR hybrid system using MgCl2 coupled with Triton X-114 as the draw solution demonstrates its potential application in wastewater treatment.

  2. Effects of C/N ratio on the performance of a hybrid sponge-assisted aerobic moving bed-anaerobic granular membrane bioreactor for municipal wastewater treatment.

    Science.gov (United States)

    Chen, C; Guo, W S; Ngo, H H; Chang, S W; Nguyen, D D; Zhang, J; Liang, S; Guo, J B; Zhang, X B

    2017-09-09

    This study aimed to evaluate the impact of C/N ratio on the performance of a hybrid sponge-assisted aerobic moving bed-anaerobic granular membrane bioreactor (SAAMB-AnGMBR) in municipal wastewater treatment. The results showed that organic removal efficiencies were above 94% at all C/N conditions. Nutrient removal was over 91% at C/N ratio of 100/5 but was negatively affected when decreasing C/N ratio to 100/10. At lower C/N ratio (100/10), more noticeable membrane fouling was caused by aggravated cake formation and pore clogging, and accumulation of extracellular polymeric substances (EPS) in the mixed liquor and sludge cake as a result of deteriorated granular quality. Foulant analysis suggested significant difference existed in the foulant organic compositions under different C/N ratios, and humic substances were dominant when the fastest fouling rate was observed. The performance of the hybrid system was found to recover when gradually increasing C/N ratio from 100/10 to 100/5. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Membrane bioreactor for waste gas treatment

    NARCIS (Netherlands)

    Reij, M.W.

    1997-01-01

    Summary

    This thesis describes the design and testing of a membrane bioreactor (MBR) for removal of organic pollutants from air. In such a bioreactor for biological gas treatment pollutants are degraded by micro-organisms. The membrane bioreactor is an alternative to other types of

  4. Effect of intermittent aeration cycle on nutrient removal and microbial community in a fluidized bed reactor-membrane bioreactor combo system.

    Science.gov (United States)

    Guadie, Awoke; Xia, Siqing; Zhang, Zhiqiang; Zeleke, Jemaneh; Guo, Wenshan; Ngo, Huu Hao; Hermanowicz, Slawomir W

    2014-03-01

    Effect of intermittent aeration cycle (IAC=15/45-60/60min) on nutrient removal and microbial community structure was investigated using a novel fluidized bed reactor-membrane bioreactor (FBR-MBR) combo system. FBR alone was found more efficient for removing PO4-P (>85%) than NH4-N (98%). Efficient nitrification, stable mixed liquor suspended solid and reduced transmembrane pressure was also achieved. Quantitative real-time polymerase chain reaction results of total bacteria 16S rRNA gene copies per mL of mixed-liquor varied from (2.48±0.42)×10(9) initial to (2.74±0.10)×10(8), (6.27±0.16)×10(9) and (9.17±1.78)×10(9) for 15/45, 45/15 and 60/60min of IACs, respectively. The results of clone library analysis revealed that Proteobacteria (59%), Firmicutes (12%) and Bacteroidetes (11%) were the dominant bacterial group in all samples. Overall, the combo system performs optimum nutrient removal and host stable microbial communities at 45/15min of IAC. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    KAUST Repository

    Ren, Lijiao

    2014-03-10

    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.

  6. Membrane bioreactors for waste gas treatment.

    NARCIS (Netherlands)

    Reij, M.W.; Keurentjes, J.T.F.; Hartmans, S.

    1998-01-01

    This review describes the recent development of membrane reactors for biological treatment of waste gases. In this type of bioreactor gaseous pollutants are transferred through a membrane to the liquid phase, where micro-organisms degrade the pollutants. The membrane bioreactor combines the

  7. Energy efficiency in membrane bioreactors.

    Science.gov (United States)

    Barillon, B; Martin Ruel, S; Langlais, C; Lazarova, V

    2013-01-01

    Energy consumption remains the key factor for the optimisation of the performance of membrane bioreactors (MBRs). This paper presents the results of the detailed energy audits of six full-scale MBRs operated by Suez Environnement in France, Spain and the USA based on on-site energy measurement and analysis of plant operation parameters and treatment performance. Specific energy consumption is compared for two different MBR configurations (flat sheet and hollow fibre membranes) and for plants with different design, loads and operation parameters. The aim of this project was to understand how the energy is consumed in MBR facilities and under which operating conditions, in order to finally provide guidelines and recommended practices for optimisation of MBR operation and design to reduce energy consumption and environmental impacts.

  8. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become

  9. Tubular membrane bioreactors for biotechnological processes.

    Science.gov (United States)

    Wolff, Christoph; Beutel, Sascha; Scheper, Thomas

    2013-02-01

    This article is an overview of bioreactors using tubular membranes such as hollow fibers or ceramic capillaries for cultivation processes. This diverse group of bioreactor is described here in regard to the membrane materials used, operational modes, and configurations. The typical advantages of this kind of system such as environments with low shear stress together with high cell densities and also disadvantages like poor oxygen supply are summed up. As the usage of tubular membrane bioreactors is not restricted to a certain organism, a brief overview of various applications covering nearly all types of cells from prokaryotic to eukaryotic cells is also given here.

  10. Proteins causing membrane fouling in membrane bioreactors.

    Science.gov (United States)

    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.

  11. An innovative membrane bioreactor for methane biohydroxylation.

    Science.gov (United States)

    Pen, N; Soussan, L; Belleville, M-P; Sanchez, J; Charmette, C; Paolucci-Jeanjean, D

    2014-12-01

    In this study, a membrane bioreactor (MBR) was developed for efficient, safe microbial methane hydroxylation with Methylosinus trichosporium OB3b. This innovative MBR, which couples a bioreactor with two gas/liquid macroporous membrane contactors supplying the two gaseous substrates (methane and oxygen) was operated in fed-batch mode. The feasibility and the reproducibility of this new biohydroxylation process were first demonstrated. The mass transfer within this MBR was twice that observed in a batch reactor in similar conditions. The productivity reached with this MBR was 75±25mgmethanol(gdrycell)(-1)h(-1). Compared to the literature, this value is 35times higher than that obtained with the only other fed-batch membrane bioreactor reported, which was run with dense membranes, and is comparable to those obtained with bioreactors fed by bubble-spargers. However, in the latter case, an explosive gas mixture can be formed, a problem that is avoided with the MBR.

  12. Fundamentals of membrane bioreactors materials, systems and membrane fouling

    CERN Document Server

    Ladewig, Bradley

    2017-01-01

    This book provides a critical, carefully researched, up-to-date summary of membranes for membrane bioreactors. It presents a comprehensive and self-contained outline of the fundamentals of membrane bioreactors, especially their relevance as an advanced water treatment technology. This outline helps to bring the technology to the readers’ attention, and positions the critical topic of membrane fouling as one of the key impediments to its more widescale adoption. The target readership includes researchers and industrial practitioners with an interest in membrane bioreactors.

  13. Gel layer formation on membranes in Membrane Bioreactors

    NARCIS (Netherlands)

    Van den Brink, P.F.H.

    2014-01-01

    The widespread application of membrane bioreactors (MBRs) for municipal wastewater treatment is hampered by membrane fouling. Fouling increases energy demand, reduces process performance and creates the need for more frequent (chemical) membrane cleaning or replacement. Membrane fouling in MBRs is k

  14. Bioreactor Scalability: Laboratory-Scale Bioreactor Design Influences Performance, Ecology, and Community Physiology in Expanded Granular Sludge Bed Bioreactors.

    Science.gov (United States)

    Connelly, Stephanie; Shin, Seung G; Dillon, Robert J; Ijaz, Umer Z; Quince, Christopher; Sloan, William T; Collins, Gavin

    2017-01-01

    Studies investigating the feasibility of new, or improved, biotechnologies, such as wastewater treatment digesters, inevitably start with laboratory-scale trials. However, it is rarely determined whether laboratory-scale results reflect full-scale performance or microbial ecology. The Expanded Granular Sludge Bed (EGSB) bioreactor, which is a high-rate anaerobic digester configuration, was used as a model to address that knowledge gap in this study. Two laboratory-scale idealizations of the EGSB-a one-dimensional and a three- dimensional scale-down of a full-scale design-were built and operated in triplicate under near-identical conditions to a full-scale EGSB. The laboratory-scale bioreactors were seeded using biomass obtained from the full-scale bioreactor, and, spent water from the distillation of whisky from maize was applied as substrate at both scales. Over 70 days, bioreactor performance, microbial ecology, and microbial community physiology were monitored at various depths in the sludge-beds using 16S rRNA gene sequencing (V4 region), specific methanogenic activity (SMA) assays, and a range of physical and chemical monitoring methods. SMA assays indicated dominance of the hydrogenotrophic pathway at full-scale whilst a more balanced activity profile developed during the laboratory-scale trials. At each scale, Methanobacterium was the dominant methanogenic genus present. Bioreactor performance overall was better at laboratory-scale than full-scale. We observed that bioreactor design at laboratory-scale significantly influenced spatial distribution of microbial community physiology and taxonomy in the bioreactor sludge-bed, with 1-D bioreactor types promoting stratification of each. In the 1-D laboratory bioreactors, increased abundance of Firmicutes was associated with both granule position in the sludge bed and increased activity against acetate and ethanol as substrates. We further observed that stratification in the sludge-bed in 1-D laboratory

  15. On modelling, monitoring and control of fixed bed bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Tali-Maamar, N.; Babary, J.P. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Dochain, D. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium)

    1995-12-31

    The working of a denitrification fixed bed bioreactor strongly depends on time and location of observing point, resulting in partial differential equations systems for the functional model. This project tries to extend the application of adaptative linearizing control schemes to non linear distributed parameters bio process. A second goal is to optimize the sensors position. (D.L.) 23 refs.

  16. MEMBRANE BIOREACTOR FOR TREATMENT OF RECALCITRANT WASTEWATERS

    Directory of Open Access Journals (Sweden)

    Suprihatin Suprihatin

    2012-02-01

    Full Text Available The low biodegradable wastewaters remain a challenge in wastewater treatment technology. The performance of membrane bioreactor systems with submerged hollow fiber micro- and ultrafiltration membrane modules were examined for purifying recalcitrant wastewaters of leachate of a municipal solid waste open dumping site and effluent of pulp and paper mill. The use of MF and UF membrane bioreactor systems showed an efficient treatment for both types wastewaters with COD reduction of 80-90%. The membrane process achieved the desirable effects of maintaining reasonably high biomass concentration and long sludge retention time, while producing a colloid or particle free effluent. For pulp and paper mill effluent a specific sludge production of 0.11 kg MLSS/kg COD removed was achieved. A permeate flux of about 5 L/m²h could be achieved with the submerged microfiltration membrane. Experiments using ultrafiltration membrane produced relatively low permeate fluxes of 2 L/m²h. By applying periodical backwash, the flux could be improved significantly. It was indicated that the particle or colloid deposition on membrane surface was suppressed by backwash, but reformation of deposit was not effectively be prevented by shear-rate effect of aeration. Particle and colloid started to accumulate soon after backwash. Construction of membrane module and operation mode played a critical role in achieving the effectiveness of aeration in minimizing deposit formation on the membrane surface.

  17. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become m

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

    Science.gov (United States)

    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.

  19. Fluidized-bed bioreactor system for the microbial solubilization of coal

    Science.gov (United States)

    Scott, C.D.; Strandberg, G.W.

    1987-09-14

    A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor. 2 figs.

  20. Fixed-bed bioreactor system for the microbial solubilization of coal

    Science.gov (United States)

    Scott, C.D.; Strandberg, G.W.

    1987-09-14

    A fixed-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fixed-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the large scale production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fixed-bed bioreactor. 1 fig., 1 tab.

  1. Fluidized-bed bioreactor process for the microbial solubiliztion of coal

    Science.gov (United States)

    Scott, Charles D.; Strandberg, Gerald W.

    1989-01-01

    A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor.

  2. Treatment of N-Nitrosodimethylamine (NDMA) in Groundwater Using a Fluidized Bed Bioreactor

    Science.gov (United States)

    2014-01-01

    FINAL REPORT Treatment of N-Nitrosodimethylamine (NDMA) in Groundwater Using a Fluidized Bed Bioreactor ESTCP Project ER-200829...08-C-0021 USING A FLUIDIZED BED BIOREACTOR 5b. GRANT NUMBER NA 5c. PROGRAM ELEMENT NUMBER NA 6. AUTHOR(St 5d. PROJECT NUMBER Hatzinger, Paul B...14.ABSTRACT This ESTCP demonstration evaluated the technical effectiveness and cost of a fluidized bed bioreactor (FBR) for treating N-ni

  3. Impact of sludge flocs on membrane fouling in membrane bioreactors

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Niessen, Wolfgang; Jørgensen, Mads Koustrup

    Membrane bioreactors (MBR) are widely used for wastewater treatment, but membrane fouling reduces membrane performance and thereby increases the cost for membranes and fouling control. Large variation in filtration properties measured as flux decline was observed for the different types of sludges...... and the physico-chemical properties, is an efficient method to reduce membrane fouling in the MBR. High concentration of suspended extracellular substances (EPS) and small particles (up to 10 µm) resulted in pronounced fouling propensity. The membrane fouling resistance was reduced at high concentration...... flocs reduced membrane fouling, and more compact and strong flocs were formed if the concentration of divalent ions were high. Sludge was fractionated by centrifugation providing supernatant with soluble EPS and colloidal particles but without flocs. Filtration test on untreated sludge and supernatant...

  4. Detachment of multi species biofilm in circulating fluidized bed bioreactor.

    Science.gov (United States)

    Patel, Ajay; Nakhla, George; Zhu, Jingxu

    2005-11-20

    In this study, the detachment rates of various microbial species from the aerobic and anoxic biofilms in a circulating fluidized bed bioreactor (CFBB) with two entirely separate aerobic and anoxic beds were investigated. Overall detachment rate coefficients for biomass, determined on the basis of volatile suspended solids (VSS), glucose and protein as well as for specific microbial groups, i.e., for nitrifiers, denitrifiers, and phosphorous accumulating organisms (PAOs), were established. Biomass detachment rates were found to increase with biomass attachment on carrier media in both beds. The detachment rate coefficients based on VSS were significantly affected by shear stress, whereas for protein, glucose and specific microbial groups, no significant effect of shear stress was observed. High detachment rates were observed for the more porous biofilm structure. The presence of nitrifiers in the anoxic biofilm and denitrifiers in the aerobic biofilm was established by the specific activity measurements. Detachment rates of PAOs in aerobic and anoxic biofilms were evaluated.

  5. Membrane fouling control by ultrasound in an anaerobic membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    SUI Pengzhe; WEN Xianghua; HUANG Xia

    2007-01-01

    In this study,ultrasound was used to control the membrane fouling online in an anaerobic membrane bioreactor (AMBR).Short-term running experiments were carried out under different operating conditions to explore feasible ultrasonic parameters.The experimental results indicated that when the crossflow velocity was more than 1.0 m/s,membrane fouling could be controlled effectively only by hydrodynamic methods without ultrasound.When ultrasound was applied,an ultrasonic power range of 60-150 W was suitable for the membrane fouling control in the experimental system.The experimental results showed that the membrane fouling was controlled so well that membrane filtration resistance(ΣR) could stay at 5×1011 m-1 for more than a week with the crossflow velocity of 0.75 m/s,which equaled the effect of crossflow velocity of more than 1.0 m/s without ultrasound.

  6. Negative Effects of Sludge Bulking in Membrane Bio-Reactor

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying; HUANG Zhi; REN Nanqi; MENG Qingjuan

    2006-01-01

    Sludge bulking property of membrane bio-reactor was investigated in this study through contrast research. When the sludge bulking appeared, the removal efficiency of COD in membrane bio-reactor increased slightly through the function of filamentous bacteria. However, the negative effects of the higher net water-head differential pressures, the high block rate of membrane pore and the great quantity of filamentous bacteria at the external surface presented at the same time. Thus, plenty of methods should be performed to control sludge bulking once it happened in membrane bio-reactor.

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

    Science.gov (United States)

    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.

  8. Simultaneous removal of phosphorus and nitrogen from sewage using a novel combo system of fluidized bed reactor-membrane bioreactor (FBR-MBR).

    Science.gov (United States)

    Guadie, Awoke; Xia, Siqing; Zhang, Zhiqiang; Guo, Wenshan; Ngo, Huu Hao; Hermanowicz, Slawomir W

    2013-12-01

    A FBR-MBR combo system was designed as a novel approach for simultaneous phosphorus and nitrogen removal from sewage. The combo system was evaluated more than 7 months under variable pH (7.5-9.5), hydraulic retention times (HRT=2-10h), intermittent aeration cycles (IAC) (on/off=60/60-15/45 min) and sludge retention times (SRT=10-60 d). Prior recovery of phosphorus as struvite in the FBR enhanced nitrogen and COD removal efficiency in MBR. Under optimum operating conditions (pH=9, HRT=6h and IAC=45/15 min), PO4(3-)-P, NH4(+)-N and COD removal efficiencies were 92.6 ± 4.2, 98.7 ± 1.2 and 99.3 ± 0.5%, respectively. Stable mixed liquor suspended solid concentration (3.0-5.0 g/L); enhanced nitrification-denitrification activity (78-92%) and reduced transmembrane pressure were also achieved. Compared to soluble microbial products, extracellular polymeric substances (EPS) showed strong correlation with fast membrane fouling. Among EPS components, carbohydrate rather than protein was associated with membrane fouling. Except HRT, all parameters considered (pH, IAC, SRT) showed a significant effect on removal efficiency. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Development of a bioreactor based on magnetically stabilized fluidized bed for bioartificial liver.

    Science.gov (United States)

    Deng, Fei; Chen, Li; Zhang, Ying; Zhao, Shan; Wang, Yu; Li, Na; Li, Shen; Guo, Xin; Ma, Xiaojun

    2015-12-01

    Bioartificial liver (BAL) based on microcapsules has been proposed as a potential treatment for acute liver failure. The bioreactors used in such BAL are usually expected to achieve sufficient flow rate and minimized void volume for effective application. Due to the superiorities in bed pressure drop and operation velocity, magnetically stabilized fluidized beds (MSFBs) show the potential to serve as ideal microcapsule-based bioreactors. In the present study, we attempted to develop a microcapsule-based MSFB bioreactor for bioartificial liver device. Compared to conventional-fluidized bed bioreactors, the bioreactor presented here increased perfusion velocity and decreased void volume significantly. Meanwhile, the mechanical stability as well as the immunoisolation property of magnetite microcapsules were well maintained during the fluidization. Besides, the magnetite microcapsules were found no toxicity to cell survival. Therefore, our study might provide a novel approach for the design of microcapsule-based bioartificial liver bioreactors.

  10. Enhancing inhibited fermentations through a dynamic electro-membrane bioreactor

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Garde, Arvid; Rype, Jens-Ulrik

    its strong potential for increasing productivity and product yield has been verified. REED uses ion exchange membranes and electrical potential gradients to selectively separate the target ion. The main limitation of using membrane separation combined with bioreactors is membrane fouling. REED...... technology ensures long operation time by reversing periodically the polarity of the imposed electrical field to significantly reduce the influence of membrane fouling. The periodic nature of the electrically driven membrane separation process makes the membrane bioreactor operation non trivial....... This challenging operation is associated with different dynamic behaviors of the individual units plus their interaction. The purpose of this contribution is to show the results of experimental and model based efforts done in order to investigate the operation of a membrane bioreactor. From modeling point of view...

  11. Biological hydrogen production using a membrane bioreactor.

    Science.gov (United States)

    Oh, Sang-Eun; Iyer, Prabha; Bruns, Mary Ann; Logan, Bruce E

    2004-07-01

    A cross-flow membrane was coupled to a chemostat to create an anaerobic membrane bioreactor (MBR) for biological hydrogen production. The reactor was fed glucose (10,000 mg/L) and inoculated with a soil inoculum heat-treated to kill non-spore-forming methanogens. Hydrogen gas was consistently produced at a concentration of 57-60% in the headspace under all conditions. When operated in chemostat mode (no flow through the membrane) at a hydraulic retention time (HRT) of 3.3 h, 90% of the glucose was removed, producing 2200 mg/L of cells and 500 mL/h of biogas. When operated in MBR mode, the solids retention time (SRT) was increased to SRT = 12 h producing a solids concentration in the reactor of 5800 mg/L. This SRT increased the overall glucose utilization (98%), the biogas production rate (640 mL/h), and the conversion efficiency of glucose-to-hydrogen from 22% (no MBR) to 25% (based on a maximum of 4 mol-H(2)/mol-glucose). When the SRT was increased from 5 h to 48 h, glucose utilization (99%) and biomass concentrations (8,800 +/- 600 mg/L) both increased. However, the biogas production decreased (310 +/- 40 mL/h) and the glucose-to-hydrogen conversion efficiency decreased from 37 +/- 4% to 18 +/- 3%. Sustained permeate flows through the membrane were in the range of 57 to 60 L/m(2) h for three different membrane pore sizes (0.3, 0.5, and 0.8 microm). Most (93.7% to 99.3%) of the membrane resistance was due to internal fouling and the reversible cake resistance, and not the membrane itself. Regular backpulsing was essential for maintaining permeate flux through the membrane. Analysis of DNA sequences using ribosomal intergenic spacer analysis indicated bacteria were most closely related to members of Clostridiaceae and Flexibacteraceae, including Clostridium acidisoli CAC237756 (97%), Linmingia china AF481148 (97%), and Cytophaga sp. MDA2507 AF238333 (99%). No PCR amplification of 16s rRNA genes was obtained when archaea-specific primers were used.

  12. Production of succinic acid in basket and mobile bed bioreactors-Comparative analysis of substrate mass transfer aspects☆

    Institute of Scientific and Technical Information of China (English)

    Anca-Irina Galaction; Dan Cacaval; Ramona-Mihaela Matran; Alexandra Tucaliuc

    2016-01-01

    The glucose mass transfer in the biosynthesis of succinic acid with immobilized Actinobacil us succinogenes cel s has been comparatively analyzed for a bioreactor with mobile bed vs. a stationary basket bioreactor. The process has been considered to occur under substrate and product inhibitory effects. The results indicated that the biore-actor with mobile bed is more efficient for biocatalyst particles with a diameter over 3 mm, while the basket bio-reactor is more efficient for smal er biocatalyst particles and basket bed thickness below 5 mm. The performances of both configurations of immobilized A. succinogenes cell beds were found to be superior to the column packed bed bioreactor.

  13. Anaerobic membrane bio-reactors for severe industrial effluents and urban spill waters: The AMBROSIUS project

    NARCIS (Netherlands)

    Van Lier, J.B.; Ozgun, H.; Ersahin, M.E.; Dereli, R.K.

    2013-01-01

    With growing application experiences from aerobic membrane bioreactors, combination of membrane and anaerobic processes become more and more attractive and feasible. In anaerobic membrane bioreactors (AnMBRs), biomass and particulate organic matter are physically retained inside the reactor, providi

  14. Hydrodynamics of an Electrochemical Membrane Bioreactor

    Science.gov (United States)

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

    2015-05-01

    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.

  15. PERFORMANCE OF NEWLY CONFIGURED SUBMERGED MEMBRANE BIOREACTOR FOR AEROBIC INDUSTRIAL WASTEWATER TREATMENT

    Directory of Open Access Journals (Sweden)

    I Gede Wenten

    2012-02-01

    Full Text Available The application of membrane to replace secondary clarifier of conventional activated sludge, known as membrane bioreactor, has led to a small footprint size of treatment with excellent effluent quality. The use of MBR eliminates almost all disadvantages encountered in conventional wastewater treatment plant such as low biomass concentration and washout of fine suspended solids. However, fouling remains as a main drawback. To minimize membrane fouling, a new configuration of submerged membrane bioreactor for aerobic industrial wastewater treatment has been developed. For the new configuration, a bed of porous particle is applied to cover the submerged ends-free mounted ultrafiltration membrane. Membrane performance was assessed based on flux productivity and selectivity. By using tapioca wastewater containing high organic matter as feed solution, reasonably high and stable fluxes around 11 l/m2.h were achieved with COD removal efficiency of more than 99%. The fouling analysis also shows that the newly configured ends-free membrane bioreactor exhibits lower irreversible resistance compared with the submerged one. In addition, the performance of pilot scale system, using a membrane module  with 10 m2 effective area and reactor tank with 120 L volume, was also assessed. The flux achieved from the pilot scale system around 8 l/m2.h with COD removal of more than 99%. Hence, this study has demonstrated the feasibility of the newly configured submerged ends-free MBR at larger scale.

  16. Sulfide oxidation in fluidized bed bioreactor using nylon support material

    Institute of Scientific and Technical Information of China (English)

    Varsha Midha; M K Jha; Apurba Dey

    2012-01-01

    A continuous fluidized bed bioreactor(FBBR)with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25,50 and 75 min and upflow velocity of 14,17 and 20 m/hr.The effects of upflow velocity,hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model.Mixed culture obtained from the activated sludge,taken from tannery effluent treatment plant,was used as a source for microorganisms.The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3,respectively.Experiments were carried out in the reactor at a temperature of(30± 2)℃,at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles.Biofilm thickness reached(42±3)μm after 15 days from reactor start-up.The sulfide oxidation,sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities.The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times.Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate.The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

  17. Sulfide oxidation in fluidized bed bioreactor using nylon support material.

    Science.gov (United States)

    Midha, Varsha; Jha, M K; Dey, Apurba

    2012-01-01

    A continuous fluidized bed bioreactor (FBBR) with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3, respectively. Experiments were carried out in the reactor at a temperature of (30 +/- 2) degrees C, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached (42 +/- 3) microm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Nguyen Cong [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Chen, Shiao-Shing, E-mail: f10919@ntut.edu.tw [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Nguyen, Hau Thi [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Ngo, Huu Hao, E-mail: h.ngo@uts.edu.au [School of Civil and Environmental Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Broadway, NSW 2007 (Australia); Guo, Wenshan [School of Civil and Environmental Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Broadway, NSW 2007 (Australia); Hao, Chan Wen [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan, ROC (China); Lin, Po-Hsun [New Materials Research and Development Dept., China Steel Corporation, Taiwan, ROC (China)

    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{sup 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, NH{sub 4}{sup +}-N and PO{sub 4}{sup 3−}-P were almost removed (> 99%) while producing relatively low NO{sub 3}{sup −}-N and NO{sub 2}{sup −}-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. - Highlights: • A novel osmotic membrane bioreactor (MBBR–OsMBR) using a novel draw solution (DS) was developed. • The MBBR–OsMBR system successfully reduced membrane fouling. • EDTA sodium coupled with Triton X-100 as novel DS resulted in low salt accumulation. • Nitrification and denitrification were well performed in a biocarrier. • The MBBR–OsMBR could remarkably remove phosphorus.

  19. Use of a gas-solid fluidized bed bioreactor for bioaugmentation

    Energy Technology Data Exchange (ETDEWEB)

    Behns, W.; Friedrich, K.; Haida, H. [Magdeburg Univ. (Germany). Inst. fuer Apparate- und Umwelttechnik

    1998-04-01

    Experimental research has shown that microbiological degradation in soils really contaminated with mineral oil hydrocarbons and hexachlorocyclohexane respectively can be accelerated and even intensified by a combined treatment in a fluidized bed bioreactor and subsequently in a remediation heap. (orig.)

  20. Arsenic removal in a sulfidogenic fixed-bed column bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Altun, Muslum, E-mail: muslumaltun@hotmail.com [Hacettepe University, Department of Chemistry, Beytepe, Ankara (Turkey); Sahinkaya, Erkan [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey); Durukan, Ilknur; Bektas, Sema [Hacettepe University, Department of Chemistry, Beytepe, Ankara (Turkey); Komnitsas, Kostas [Technical University of Crete, Department of Mineral Resources Engineering, Chania (Greece)

    2014-03-01

    Highlights: • Sulfidogenic treatment of As-containing AMD was investigated. • High rate simultaneous removal of As and Fe was achieved. • As was removed without adding alkalinity or adjusting pH. • As and Fe removal mechanisms were elucidated. - Abstract: In the present study, the bioremoval of arsenic from synthetic acidic wastewater containing arsenate (As{sup 5+}) (0.5–20 mg/L), ferrous iron (Fe{sup 2+}) (100–200 mg/L) and sulfate (2000 mg/L) was investigated in an ethanol fed (780–1560 mg/L chemical oxygen demand (COD)) anaerobic up-flow fixed bed column bioreactor at constant hydraulic retention time (HRT) of 9.6 h. Arsenic removal efficiency was low and averaged 8% in case iron was not supplemented to the synthetic wastewater. Neutral to slightly alkaline pH and high sulfide concentration in the bioreactor retarded the precipitation of arsenic. Addition of 100 mg/L Fe{sup 2+} increased arsenic removal efficiency to 63%. Further increase of influent Fe{sup 2+} concentration to 200 mg/L improved arsenic removal to 85%. Decrease of influent COD concentration to its half, 780 mg/L, resulted in further increase of As removal to 96% when Fe{sup 2+} and As{sup 5+} concentrations remained at 200 mg/L and 20 mg/L, respectively. As a result of the sulfidogenic activity in the bioreactor the effluent pH and alkalinity concentration averaged 7.4 ± 0.2 and 1736 ± 239 mg CaCO{sub 3}/L respectively. Electron flow from ethanol to sulfate averaged 72 ± 10%. X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses were carried out to identify the nature of the precipitate generated by sulfate reducing bacteria (SRB) activity. Precipitation of arsenic in the form of As{sub 2}S{sub 3} (orpiment) and co-precipitation with ferrous sulfide (FeS), pyrite (FeS{sub 2}) or arsenopyrite (FeAsS) were the main arsenic removal mechanisms.

  1. Mechanism of calcium mitigating membrane fouling in submerged membrane bioreactors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hanmin; XIA Jie; YANG Yang; WANG Zixing; YANG Fenglin

    2009-01-01

    Two parallel membrane bioreactors (MBRs) were operated under different calcium dosages (168.5, 27 mg/L) to gain a better understanding of the mechanism of retarding membrane fouling by the addition of calcium.The results showed that the particle size of sludge flocs increased and the particle size distribution tended to be narrow at the optimum dosage (168.5 mg/L).Calcium was effective in decreasing loosely bound extracellular polymeric substances (LB-EPS) in microbial flocs and soluble microbial products (SMP) in the supernatant at the dosage of 168.5 mg/L by strengthening the neutralization and bridging of EPS with flocs.Furthermore, the amount of CODS and CODC decreased in both the mixed liquor and the fouling cake layer on the membrane surface.In order to compare the filtration characteristics of cake layers from the MBRs with the two calcium dosages, the specific cake resistance and the compressibility coefficient were measured.The specific cake resistance from the MBR with optimum dosage (168.5 mg/L) was distinctly lower than that with low dosage (27 mg/L).The compressibility coefficient of the cake layers under different dosages were respectively attained as 0.65, 0.91.Scanning electron microscopy (SEM) and three-dimensional confocal scanning laser microscope analysis (CLSM) images were utilized to observe the gel layer directly.

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

    Science.gov (United States)

    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. MBBR-OsMBR was reversible and removed by a physical cleaning technique.

  3. Lactic acid Production with in situ Extraction in Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    Hamidreza Ghafouri Taleghani

    2017-01-01

    Full Text Available Background and Objective: Lactic acid is widely used in the food, chemical and pharmaceutical industries. The major problems associated with lactic acid production are substrate and end-product inhibition, and by-product formation. Membrane technologyrepresents one of the most effective processes for lactic acid production. The aim of this work is to increase cell density and lactic acid productivity due to reduced inhibition effect of substrate and product in membrane bioreactor.Material and Methods: In this work, lactic acid was produced from lactose in membrane bioreactor. A laboratory scale membrane bioreactor was designed and fabricated. Five types of commercial membranes were tested at the same operating conditions (transmembrane pressure: 500 KPa and temperature: 25°C. The effects of initial lactose concentration and dilution rate on biomass growth, lactic acid production and substrate utilization were evaluated.Results and Conclusion: The high lactose retention of 79% v v-1 and low lactic acid retention of 22% v v-1 were obtained with NF1 membrane; therefore, this membrane was selected for membrane bioreactor. The maximal productivity of 17.1 g l-1 h-1 was obtainedwith the lactic acid concentration of 71.5 g l-1 at the dilution rate of 0.24 h−1. The maximum concentration of lactic acid was obtained at the dilution rate of 0.04 h−1. The inhibiting effect of lactic acid was not observed at high initial lactose concentration. The critical lactose concentration at which the cell growth severely hampered was 150 g l-1. This study proved that membrane bioreactor had great advantages such as elimination of substrate and product inhibition, high concentration of process substrate, high cell density,and high lactic acid productivity.Conflict of interest: There is no conflict of interest.

  4. ANAEROBIC MEMBRANE BIOREACTORS FOR DOMESTIC WASTEWATER TREATMENT. PRELIMINARY STUDY

    Directory of Open Access Journals (Sweden)

    Luisa Vera

    2014-12-01

    Full Text Available The operation of submerged anaerobic membrane bioreactors (SAnMBRs for domestic wastewaters treatment was studied in laboratory scale, with the objective to define sustainable filtration conditions of the suspensions along the process. During continuous experiments, the organic matter degradation by anaerobic way showed an average DQOT removal of 85% and 93%. Indeed, the degradation generated biogas after 12 days of operation and its relative methane composition was of 60% after 25 days of operation. Additionally, the comparison between membrane bioreactors (MBRs performance in aerobic and anaerobic conditions in filterability terms, reported that both systems behave similarly once reached the stationary state.

  5. Wastewater treatments by membrane bioreactors (MBR); Bioreactores de membrana (MBR) para la depuracion de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Guardino Ferre, R.

    2001-07-01

    Wastewater treatments by membrane bioreactors (MBR), are a good alternative of treatment to the conventional processes when wish to obtain very high quality of the treated water or to try high load contaminants in low flow. Simultaneously, the article explains the significant reduction of the wastewater treatment plant space, eliminating the secondary septic tank. (Author) 7 refs.

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

    Science.gov (United States)

    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.

  7. Enhanced butyric acid tolerance and bioproduction by Clostridium tyrobutyricum immobilized in a fibrous bed bioreactor.

    Science.gov (United States)

    Jiang, Ling; Wang, Jufang; Liang, Shizhong; Cai, Jin; Xu, Zhinan; Cen, Peilin; Yang, Shangtian; Li, Shuang

    2011-01-01

    Repeated fed-batch fermentation of glucose by Clostridium tyrobutyricum immobilized in a fibrous bed bioreactor (FBB) was successfully employed to produce butyric acid at a high final concentration as well as to adapt a butyric-acid-tolerant strain. At the end of the eighth fed-batch fermentation, the butyric acid concentration reached 86.9 ± 2.17 g/L, which to our knowledge is the highest butyric acid concentration ever produced in the traditional fermentation process. To understand the mechanism and factors contributing to the improved butyric acid production and enhanced acid tolerance, adapted strains were harvested from the FBB and characterized for their physiological properties, including specific growth rate, acid-forming enzymes, intracellular pH, membrane-bound ATPase and cell morphology. Compared with the original culture used to seed the bioreactor, the adapted culture showed significantly reduced inhibition effects of butyric acid on specific growth rate, cellular activities of butyric-acid-forming enzyme phosphotransbutyrylase (PTB) and ATPase, together with elevated intracellular pH, and elongated rod morphology.

  8. Simultaneous nitrogen and organics removal using membrane aeration and effluent ultrafiltration in an anaerobic fluidized membrane bioreactor

    KAUST Repository

    Ye, Yaoli

    2017-08-03

    Dissolved methane and a lack of nutrient removal are two concerns for treatment of wastewater using anaerobic fluidized bed membrane bioreactors (AFMBRs). Membrane aerators were integrated into an AFMBR to form an Aeration membrane fluidized bed membrane bioreactor (AeMFMBR) capable of simultaneous removal of organic matter and ammonia without production of dissolved methane. Good effluent quality was obtained with no detectable suspended solids, 93±5% of chemical oxygen demand (COD) removal to 14±11 mg/L, and 74±8% of total ammonia (TA) removal to 12±3 mg-N/L for domestic wastewater (COD of 193±23 mg/L and TA of 49±5 mg-N/L) treatment. Nitrate and nitrite concentrations were always low (< 1 mg-N/L) during continuous flow treatment. Membrane fouling was well controlled by fluidization of the granular activated carbon (GAC) particles (transmembrane pressures maintained <3 kPa). Analysis of the microbial communities suggested that nitrogen removal was due to nitrification and denitrification based on the presence of microorganisms associated with these processes.

  9. Anaerobic Membrane Bioreactors For Cost-Effective Municipal Water Reuse

    NARCIS (Netherlands)

    Özgün, H.

    2015-01-01

    In recent years, anaerobic membrane bioreactor (AnMBR) technology has been increasingly researched for municipal wastewater treatment as a means to produce nutrient-rich, solids free effluents with low levels of pathogens, while occupying a small footprint. An AnMBR can be used not only for on-site

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

    NARCIS (Netherlands)

    Suarez Zuluaga, D.A.; Timmers, P.H.A.; Plugge, C.M.; Stams, A.J.M.; Buisman, C.J.N.; Weijma, J.

    2016-01-01

    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 li

  11. Performance of Submerged Membrane Bioreactor for Domestic Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the present research, a submerged membrane bioreactor was tested to treat domestic wastewater. Three experimental runs were conducted all with a hydraulic retention time of 5h and sludge retention times (SRTs) of 5, 10, and 20 d. The pollutant removal performance of the membrane bioreactor, the membrane effluent quality, and a kinetic model for sludge growth in the bioreactor were investigated. The combined process was capable of removing over 90% of both COD (chemical oxygen demand) and NH3-N on the average. The total removal for COD was almost independent of SRT, but that for NH3-N improved with increasing SRT. Membrane effluent quality meets the water quality standard for reuse issued by the Ministry of Construction of China. Increasing SRT causes the concentrations of suspended solids (SS) and volatile suspended solids (VSS) in the bioreactor to increase. However, the ratio of VSS/SS did not change much. Kinetic analysis showed that the sludge yield coefficient (kg-VSS·kg-COD-1) and the endogenous coefficient of microorganisms were 0.25 and 0.04d-1, which are similar to those of the conventional activated sludge process.

  12. Anaerobic Membrane Bioreactors For Cost-Effective Municipal Water Reuse

    NARCIS (Netherlands)

    Özgün, H.

    2015-01-01

    In recent years, anaerobic membrane bioreactor (AnMBR) technology has been increasingly researched for municipal wastewater treatment as a means to produce nutrient-rich, solids free effluents with low levels of pathogens, while occupying a small footprint. An AnMBR can be used not only for on-site

  13. CFD Simulation of Fouling by Biological materials in Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    Raziye, Ahmadi

    2016-06-01

    Full Text Available In recent years membrane bioreactors filtration is increasingly used in wastewater treatment to enhance the quality of wastewater. The main problem in preventing the widespread use of membrane bioreactor is its congestion which has a severe impact on output flux to time ratio. If solid suspensions with high concentrations exist in the wastewater, this influence will be even more severe. In addition to the suspended solids in the liquid mixture, Extracellular polymeric materials (EPS and soluble microbial products (SMP are also known as basic microbial products that cause membrane fouling. EPS can be calculated within and on the membrane which increases the viscosity of suspended solids in the liquid mixture and increases filtration resistance. SMPs cannot penetrate the pores of the ultra filtration membrane due to the limited size of the pores which would cause fouling in membrane processes. According to the above issues, providing a model that indicates the properties and conditions of formation and destruction of SMP and EPS at the same time seems necessary. In this paper, CFD simulation of biological fouling in membrane bioreactor is provided using Fluent software.

  14. Fouling Characteristics and Prevention Techniques for Membrane Bioreactor

    Institute of Scientific and Technical Information of China (English)

    LU Hua; WANG Zhi-qiang; YANG Jin-ying

    2005-01-01

    Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and permeated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.

  15. Efficacy of Aspergillus sp. for degradation of chlorpyrifos in batch and continuous aerated packed bed bioreactors.

    Science.gov (United States)

    Yadav, Maya; Srivastva, Navnita; Shukla, Awadhesh Kumar; Singh, Ram Sharan; Upadhyay, Siddh Nath; Dubey, Suresh Kumar

    2015-01-01

    Aerobic biodegradation of chlorpyrifos (CP) by Aspergillus sp. was investigated in batch and continuous packed bed bioreactors. The optimal process parameters for achieving the maximum removal efficiency (RE), determined using a batch bioreactor packed with polyurethane foam pieces, were inoculum level: 2.5 mg (wet weight) mL(-1), pH 7.0, temperature 28 °C, DO 5.8 mg L(-1), and CP concentration 300 mg L(-1). The continuous packed bed bioreactor was operated at flow rates ranging from 10 to 40 mL h(-1) while keeping other parameters at their optimal level. Steady-state CP removal efficiencies greater than 85 % were obtained up to the inlet loading of 180 mg L(-1) d(-1). The continuous bioreactor behaved as a plug flow unit and was able to stabilize quickly after perturbation in the inlet loading.

  16. Development of an energy-saving anaerobic hybrid membrane bioreactors for 2-chlorophenol-contained wastewater treatment.

    Science.gov (United States)

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

    2015-12-01

    A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater.

  17. Anaerobic electrochemical membrane bioreactor and process for wastewater treatment

    KAUST Repository

    Amy, Gary

    2015-07-09

    An anaerobic electrochemical membrane bioreactor (AnEMBR) can include a vessel into which wastewater can be introduced, an anode electrode in the vessel suitable for supporting electrochemically active microorganisms (EAB, also can be referred to as anode reducing bacteria, exoelectrogens, or electricigens) that oxidize organic compounds in the wastewater, and a cathode membrane electrode in the vessel, which is configured to pass a treated liquid through the membrane while retaining the electrochemically active microorganisms and the hydrogenotrophic methanogens (for example, the key functional microbial communities, including EAB, methanogens and possible synergistic fermenters) in the vessel. The cathode membrane electrode can be suitable for catalyzing the hydrogen evolution reaction to generate hydro en.

  18. Biogas Production from Citrus Waste by Membrane Bioreactor

    Science.gov (United States)

    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

  19. Biogas Production from Citrus Waste by Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    Rachma Wikandari

    2014-08-01

    Full Text Available 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.

  20. Packed Bed Bioreactor for the Isolation and Expansion of Placental-Derived Mesenchymal Stromal Cells.

    Directory of Open Access Journals (Sweden)

    Michael J Osiecki

    Full Text Available Large numbers of Mesenchymal stem/stromal cells (MSCs are required for clinical relevant doses to treat a number of diseases. To economically manufacture these MSCs, an automated bioreactor system will be required. Herein we describe the development of a scalable closed-system, packed bed bioreactor suitable for large-scale MSCs expansion. The packed bed was formed from fused polystyrene pellets that were air plasma treated to endow them with a surface chemistry similar to traditional tissue culture plastic. The packed bed was encased within a gas permeable shell to decouple the medium nutrient supply and gas exchange. This enabled a significant reduction in medium flow rates, thus reducing shear and even facilitating single pass medium exchange. The system was optimised in a small-scale bioreactor format (160 cm2 with murine-derived green fluorescent protein-expressing MSCs, and then scaled-up to a 2800 cm2 format. We demonstrated that placental derived MSCs could be isolated directly within the bioreactor and subsequently expanded. Our results demonstrate that the closed system large-scale packed bed bioreactor is an effective and scalable tool for large-scale isolation and expansion of MSCs.

  1. Packed Bed Bioreactor for the Isolation and Expansion of Placental-Derived Mesenchymal Stromal Cells

    Science.gov (United States)

    Osiecki, Michael J.; Michl, Thomas D.; Kul Babur, Betul; Kabiri, Mahboubeh; Atkinson, Kerry; Lott, William B.; Griesser, Hans J.; Doran, Michael R.

    2015-01-01

    Large numbers of Mesenchymal stem/stromal cells (MSCs) are required for clinical relevant doses to treat a number of diseases. To economically manufacture these MSCs, an automated bioreactor system will be required. Herein we describe the development of a scalable closed-system, packed bed bioreactor suitable for large-scale MSCs expansion. The packed bed was formed from fused polystyrene pellets that were air plasma treated to endow them with a surface chemistry similar to traditional tissue culture plastic. The packed bed was encased within a gas permeable shell to decouple the medium nutrient supply and gas exchange. This enabled a significant reduction in medium flow rates, thus reducing shear and even facilitating single pass medium exchange. The system was optimised in a small-scale bioreactor format (160 cm2) with murine-derived green fluorescent protein-expressing MSCs, and then scaled-up to a 2800 cm2 format. We demonstrated that placental derived MSCs could be isolated directly within the bioreactor and subsequently expanded. Our results demonstrate that the closed system large-scale packed bed bioreactor is an effective and scalable tool for large-scale isolation and expansion of MSCs. PMID:26660475

  2. Packed Bed Bioreactor for the Isolation and Expansion of Placental-Derived Mesenchymal Stromal Cells.

    Science.gov (United States)

    Osiecki, Michael J; Michl, Thomas D; Kul Babur, Betul; Kabiri, Mahboubeh; Atkinson, Kerry; Lott, William B; Griesser, Hans J; Doran, Michael R

    2015-01-01

    Large numbers of Mesenchymal stem/stromal cells (MSCs) are required for clinical relevant doses to treat a number of diseases. To economically manufacture these MSCs, an automated bioreactor system will be required. Herein we describe the development of a scalable closed-system, packed bed bioreactor suitable for large-scale MSCs expansion. The packed bed was formed from fused polystyrene pellets that were air plasma treated to endow them with a surface chemistry similar to traditional tissue culture plastic. The packed bed was encased within a gas permeable shell to decouple the medium nutrient supply and gas exchange. This enabled a significant reduction in medium flow rates, thus reducing shear and even facilitating single pass medium exchange. The system was optimised in a small-scale bioreactor format (160 cm2) with murine-derived green fluorescent protein-expressing MSCs, and then scaled-up to a 2800 cm2 format. We demonstrated that placental derived MSCs could be isolated directly within the bioreactor and subsequently expanded. Our results demonstrate that the closed system large-scale packed bed bioreactor is an effective and scalable tool for large-scale isolation and expansion of MSCs.

  3. Osmotic membrane bioreactor for phenol biodegradation under continuous operation

    Energy Technology Data Exchange (ETDEWEB)

    Praveen, Prashant; Loh, Kai-Chee, E-mail: chelohkc@nus.edu.sg

    2016-03-15

    Highlights: • Osmotic membrane bioreactor was used for phenol biodegradation in continuous mode. • Extractant impregnated membranes were used to alleviate substrate inhibition. • Phenol removal was achieved through both biodegradation and membrane rejection. • Phenol concentrations up to 2500 mg/L were treated at HRT varying in 2.8–14 h. • A biofilm removal strategy was formulated to improve bioreactor sustainability. - Abstract: 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 600–2000 mg/L, and also at spiked concentrations of 2500 mg/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 5500 mg/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 7.4 h. A washing cycle, comprising 1 h osmotic backwashing using 0.5 M NaCl and 2 h washing with water, facilitated biofilm removal from the membranes. Characterization of the extracellular polymeric substances (EPS) through FTIR showed peaks between 1700 and 1500 cm{sup −1}, 1450–1450 cm{sup −1} and 1200–1000 cm{sup −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.

  4. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems

    Science.gov (United States)

    Li, Jianzhou; Yu, Liang; Chen, Ermei; Zhu, Danhua; Zhang, Yimin; Li, LanJuan

    2016-01-01

    A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB) operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB). The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells) were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases. PMID:26840840

  5. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems.

    Directory of Open Access Journals (Sweden)

    Juan Lu

    Full Text Available A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB. The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases.

  6. A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems.

    Science.gov (United States)

    Lu, Juan; Zhang, Xiaoqian; Li, Jianzhou; Yu, Liang; Chen, Ermei; Zhu, Danhua; Zhang, Yimin; Li, LanJuan

    2016-01-01

    A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB) operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB). The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells) were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases.

  7. Sludge Bulking Property of Membrane Bio-reactor in Albumen Wqastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Albumen wastewater was treated by Membrane Bio-reactor. Sludge bulking property of Membrane Bio-Reactor was investigated in this study through contrast research. When the sludge bulking appeared, the removal efficiency of COD in Membrane Bio-reactor increased slightly under the function of filamentous bacteria. However, the negative effects of the higher net water-head differential pressures,the higher block rate of membrane pore and the great quantity of filamentous bacteria at the externalsurface pres...

  8. Comparison of the Efficiency of Moving- and Fixed-bed Bioreactors for Treatment of High-strength Synthetic Wastewater

    OpenAIRE

    Rezaee, A.; S Jorfi; Cheshmeh Soltani, R. D

    2012-01-01

    A lab-scale Plexiglas cubic container as a pre-aeration reactor with total volume of 10 L, and two integrated bioreactors including a moving-bed bioreactor (MBBR) and a fixed-bed bioreactor with total volume of 30 L separately were used for experimental study. The main purpose was to compare the performance of moving-bed and fixed-bed reactors for degradation of high organic loading in synthetic wastewater. Varying organic loadings of 0.5 to 9 kg COD m3 d–1 were applied. Generally, the tot...

  9. A pulsing device for packed-bed bioreactors. Pt. 2; Application to alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Sanroman, A. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain)); Roca, E. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain)); Nunez, M.J. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain)); Lema, J.M. (Chemical Engineering Dept., Univ. of Santiago de Compostela (Spain))

    1994-02-01

    When the immobilized cells are employed in packed-bed bioreactors several problems appear. To overcome these drawbacks, a new bioreactor based on the use of pulsed systems was developed. In this work, we study the glucose fermentation by immobilized Saccharomyces cerevisiae in a packed-bed bioreactor. A comparative study was then carried out for continuous fermentation in two packed-bed bioreactors, one of them with pulsed flow. The determination of the axial dispersion coefficients indicates that by introducing the pulsation, the hydraulic behaviour is closer to the plug flow model. In both cases, the residence time tested varied from 0.8 to 2.6 h. A higher ethanol concentration and productivity (increases up to 16%) were achieved with the pulsated reactors. The volumes occupied by the CO[sub 2] were 5.22% and 9.45% for fermentation with/without pulsation respectively. An activity test of the particles from the different sections revealed that the concentration and viability of bioparticles from the two bioreactors are similar. From the results we conclude that the improvements of the process are attributable to a mechanical effect rather than to physiological changes of microorganisms. (orig.)

  10. Wastewater treatment in a submerged anaerobic membrane bioreactor.

    Science.gov (United States)

    Casu, Stefania; Crispino, Nedda A; Farina, Roberto; Mattioli, Davide; Ferraris, Marco; Spagni, Alessandro

    2012-01-01

    Although most membrane bioreactors are used under aerobic conditions, over the last few years there has been increased interest in their application for anaerobic processes. This paper presents the results obtained when a bench-scale submerged anaerobic membrane bioreactor was used for the treatment of wastewaters generated in the agro-food industry. The reactor was fed with synthetic wastewater consisting of cheese whey and sucrose, and volumetric organic loading rates (OLRs) ranging from 1.5 to 13 kgCOD/(m(3)*d) were applied. Under the operating conditions studied, the maximum applicable OLR was between 6 and 10 gCOD/(g*L), which fell within the ranges of the high-rate anaerobic wastewater treatment systems, while high concentrations of volatile fatty acids were produced at higher OLR rates. With an OLR of 1.5-10 gCOD/(g*L), the reactor showed 94% COD removal, whereas this value dropped to 33% with the highest applied OLR of 13 gCOD/(g*L). The study therefore confirms that membrane bioreactors can be used for anaerobic wastewater treatment.

  11. Sewage treatment by a low energy membrane bioreactor.

    Science.gov (United States)

    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.

  12. Continuous, packed-bed, enzymatic bioreactor production and stability of feruloyl soy glycerides

    Science.gov (United States)

    The synthesis of feruloyl soy glycerides was demonstrated on a pilot-scale (1 metric ton/year) in a continuous, four-column series, packed-bed, enzymatic bioreactor. Ethyl ferulate and soybean oil were combined and converted at 3.5 kg/d over Candida antartica lipase B immobilized on an acrylic rein ...

  13. Continuous Degradation of Chitosan in a Convoluted Fibrous Bed Bioreactor with Immobilized Trichoderma reesei

    Institute of Scientific and Technical Information of China (English)

    WUMianbin; XIALiming; 等

    2002-01-01

    Continuous hydrolysis of chitosan was performed in a convoluted fibrous bed bioreactor (CFBB) with immobilized T. reesei. At dilution rate of 0.4d-1 and substrate concentration of 2% (mass vs. volume), the average degree of polymerization of hydrolysate can be kept at 1.25-1.35, which can be easily regulated by changing dilution rate or inlet chitosan concentration.

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

    Science.gov (United States)

    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.

  15. Adaptation of Clostridium tyrobutyricum for enhanced tolerance to butyric acid in a fibrous-bed bioreactor.

    Science.gov (United States)

    Zhu, Ying; Yang, Shang-Tian

    2003-01-01

    By immobilization in a fibrous-bed bioreactor (FBB), we succeeded in adapting and selecting an acid-tolerant strain of Clostridium tyrobutyricum that can produce high concentrations of butyrate from glucose and xylose. This mutant grew well under high butyrate concentrations (>30 g/L) and had better fermentative ability as compared to the wild-type strain used to seed the bioreactor. Kinetic analysis of butyrate inhibition on cell growth, acid-forming enzymes, and ATPase activity showed that the adapted cells from the FBB are physiologically different from the original wild type. Compared to the wild type, the adapted culture's maximum specific growth rate increased by 2.3-fold and its growth tolerance to butyrate inhibition increased by 29-fold. The key enzymes in the butyrate-forming pathway, phosphotransbutyrylase (PTB) and butyrate kinase (BK), were also more active in the mutant, with 175% higher PTB and 146% higher BK activities. Also, the mutant's ATPase was less sensitive to inhibition by butyric acid, as indicated by a 4-fold increase in the inhibition rate constant, and was more resistant to the enzyme inhibitor N,N'-dicyclohexylcarbodiimide (DCCD). The lower ATPase sensitivity to butyrate inhibition might have contributed to the increased growth tolerance to butyrate inhibition, which also might be attributed to the higher percentage of saturated fatty acids in the membrane phospholipids (74% in the mutant vs 69% in the wild type). This study shows that cell immobilization in the FBB provides an effective means for in-process adaptation and selection of mutant with higher tolerance to inhibitory fermentation product.

  16. Filterability and Sludge Concentration in Membrane Bioreactors

    NARCIS (Netherlands)

    Lousada-Ferreira, M.

    2011-01-01

    The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of th

  17. Ceramic Ultra Filtration Membrane Bioreactor for Domestic Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A long term domestic wastewater treatment experiment was conducted using a recirculating ceramic ultra filtration membrane bioreactor (CUFMB) system. Three experiments were run with a hydraulic retention time of 5h, sludge retention times of 5d, 15d, and 30d and a membrane surface flow rate of 4m/s. The experiment studied the membrane fouling mechanism and cleaning techniques. The results show that a CUFMB system can provide continuous good quality effluent which is completely acceptable for reuse. The system is also not affected by fluctuations of the inlet flow. The CUFMB sludge loading rate is similar to that of conventional biological treatment units. However, the volumetric loading rate of the CUFMB is 24 times that of conventional biological treatment units. Membrane fouling occurs due to channel clogging, which could be easily removed, and surface fouling, which can be effectively removed using the method described in this work which includes water rinsing, base cleaning, and acid washing.

  18. Bioreactors with Light-Beads Fluidized Bed: The Voidage Function and its Expression

    Directory of Open Access Journals (Sweden)

    Iliev Vasil

    2014-12-01

    Full Text Available Light-beads fluidized bed bioreactors with gel particles are an attractive alternative for the implementation of a system with immobilized cells. They have a number of advantages: soft operating conditions, ability to work in an ideal mixing regime, intensification of heat- and mass transfer processes in the fermentation system. The expansion characteristics of the fluidized bed were investigated in the present work. The fluidized bed expansion was described using the voidage function. It was found that the voidage can be described by nonlinear regression relationships and the regression coefficients were a function of the particles parameters.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. Influence of membrane properties on fouling in submerged membrane bioreactors

    NARCIS (Netherlands)

    Marel, van der P.; Zwijnenburg, A.; Kemperman, A.; Wessling, M.; Temmink, B.G.; Meer, van der W.

    2010-01-01

    Polymeric flat-sheet membranes with different properties were used in filtration experiments with activated sludge from a pilot-scale MBR to investigate the influence of membrane pore size, surface porosity, pore morphology, and hydrophobicity on membrane fouling. An improved flux-step method was us

  3. Production of rhEPO with a serum-free medium in the packed bed bioreactor.

    Science.gov (United States)

    Deng, J; Yang, Q; Cheng, X; Li, L; Zhou, J

    1997-01-01

    Recombinant CHO (C2) cells producing human erythropoietin (rhEPO) were cultured with DMEM:F12 media containing 5% FBS for 8-10 days in a packed bed bioreactor, then rhEPO was produced with a serum-free medium (SFM-p) which was prepared in our laboratory. The SFM-p medium can support the growth of C2 cells and the production of rhEPO, and furthermore, it easily separates rhEPO from the culture supernatant. The cell culture in a packed bed bioreactor system using SFM-p was maintained in a stable condition for 20-25 days. The expression level of rhEPO was 12-28.4 mg/L. The bioreactor productivity was 71.0 mg/L.d and increased by 12-14 fold over that of the roller bottle. The glucose consumption rate was 21 g/L.d. At the end of 30 days of perfusion circulation, a final cell density of over 3.0 x 10(7)/ml of culture volume was achieved. Since the cells were entrapped in the polyester disk, the culture supernatant contained only a few detachment cells. Variations in lactate and ammonia production in the reactor were observed, and results showed that the productions of lactate and ammonia by the bioreactor were 3.5 g/L and 5 mmol/L, respectively, and did not affect the expression of interest protein. This experiment demonstrates that SFM-p is suitable for the growth and rhEPO production of recombinant C2 in the packed bed bioreactor.

  4. Production of bacterial cellulose membranes in a modified airlift bioreactor by Gluconacetobacter xylinus.

    Science.gov (United States)

    Wu, Sheng-Chi; Li, Meng-Hsun

    2015-10-01

    In this study, a novel bioreactor for producing bacterial cellulose (BC) is proposed. Traditional BC production uses static culture conditions and produces a gelatinous membrane. The potential for using various types of bioreactor, including a stirred tank, conventional airlift, and modified airlift with a rectangular wire-mesh draft tube, in large-scale production has been investigated. The BC obtained from these bioreactors is fibrous or in pellet form. Our proposed airlift bioreactor produces a membrane-type BC from Gluconacetobacter xylinus, the water-holding capacity of which is greater than that of cellulose types produced using static cultivation methods. The Young's modulus of the product can be manipulated by varying the number of net plates in the modified airlift bioreactor. The BC membrane produced using the proposed bioreactor exhibits potential for practical application.

  5. A REVIEW ON SEWAGE TREATMENT AND POLISHING USING MOVING BED BIOREACTOR (MBBR)

    OpenAIRE

    JAMAL ALI KAWAN; HASSIMI ABU HASAN; FATIHAH SUJA; OTHMAN BIN JAAFAR; RAKMI ABD-RAHMAN

    2016-01-01

    Effluent treatment and polishing using moving bed bioreactors (MBBRs) are advanced technique in biological treatment operations become increasing widely and popular use all over the world to treat various types of effluents with very different operating status. It is a combination of two separate processes suspended and attached growth systems for the treatment in order to minimize the concentrations of the contaminated parameters at the required level for reuse or final destination. The M...

  6. Membrane bioreactors and their uses in wastewater treatments.

    Science.gov (United States)

    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.

  7. Membrane bioreactors and their uses in wastewater treatments

    Energy Technology Data Exchange (ETDEWEB)

    Le-Clech, Pierre [New South Wales Univ., Sydney (Australia). UNESCO Centre for Membrane Science and Technology

    2010-12-15

    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. (orig.)

  8. Decolourisation of textile wastewater in a submerged anaerobic membrane bioreactor.

    Science.gov (United States)

    Spagni, Alessandro; Casu, Stefania; Grilli, Selene

    2012-08-01

    Azo dye decolourisation can be easily achieved by biological reduction under anaerobic conditions. The aim of this study was to evaluate the applicability of submerged anaerobic membrane bioreactors (SAMBRs) for the decolourisation of dyeing wastewater containing azo dyes. The reactive orange 16 was used as model of an azo dye. The results demonstrated that very high decolourisation (higher than 99%) can be achieved by SAMBRs. Although decolourisation was not significantly influenced by the azo dye concentrations up to 3.2 g L(-1), methane production was greatly inhibited (up to 80-85%). Since volatile fatty acids accumulated in the treatment system with the azo dye concentration increase, methanogenes seem to be the most sensitive microbial populations of the anaerobic ecological community. The results demonstrated that anaerobic process combined with membrane filtration can deal with highly concentrated wastewaters that result from stream separation of industrial discharges.

  9. Treatment of dairy wastewater with a membrane bioreactor

    Directory of Open Access Journals (Sweden)

    L. H. Andrade

    2013-12-01

    Full Text Available Among the food industries, the dairy industry is considered to be the most polluting one because of the large volume of wastewater generated and its high organic load. In this study, an aerobic membrane bioreactor (MBR was used for the treatment of wastewater from a large dairy industry and two hydraulic retention times (HRT, 6 and 8 hours, were evaluated. For both HRTs removal efficiencies of organic matter of 99% were obtained. Despite high permeate flux (27.5 L/h.m², the system operated fairly stablely. The molecular weight distribution of feed, permeate and mixed liquor showed that only the low molecular weight fraction is efficiently degraded by biomass and that the membrane has an essential role in producing a permeate of excellent quality.

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

    Science.gov (United States)

    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.

  11. Reduction of Membrane Fouling in Membrane Bioreactors - Development of Innovative and Sustainable Techniques

    OpenAIRE

    Siembida-Lösch, Barbara

    2011-01-01

    Over the past decade, membrane technology has become a worldwide implemented, acknowledged separation process. Although membrane bioreactors (MBRs) still require further research efforts re-garding operating and economic efficiency, they offer considerable advantages compared to conven-tional activated sludge systems, such as smaller foot print, modular construction, and superior effluent quality. They are especially preferred in cases where stringent water quality requirements have to be gua...

  12. Removal of trace organics by anaerobic membrane bioreactors.

    Science.gov (United States)

    Monsalvo, Victor M; McDonald, James A; Khan, Stuart J; Le-Clech, Pierre

    2014-02-01

    The biological removal of 38 trace organics (pharmaceuticals, endocrine disruptors, personal care products and pesticides) was studied in an anaerobic membrane bioreactor (AnMBR). This work presents complete information on the different removal mechanisms involved in the removal of trace organics in this process. In particular, it is focused on advanced characterization of the relative amount of TO accumulated within the fouling layers formed on the membranes. The results show that only 9 out of 38 compounds were removed by more than 90% while 23 compounds were removed by less than 50%. These compounds are therefore removed in an AnMBR biologically and partially adsorbed and retained by flocs and the deposition developed on the membranes, respectively. A total amount of 288 mg of trace organics was retained per m(2) of membrane, which were distributed along the different fouling layers. Among the trace organics analyzed, 17α-ethynylestradiol, estrone, octylphenol and bisphenol A were the most retained by the fouling layers. Among the fouling layers deposited on the membranes, the non-readily detachable layer has been identified as the main barrier for trace organics.

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

    Science.gov (United States)

    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.

  14. Large-scale clinical-grade retroviral vector production in a fixed-bed bioreactor.

    Science.gov (United States)

    Wang, Xiuyan; Olszewska, Malgorzata; Qu, Jinrong; Wasielewska, Teresa; Bartido, Shirley; Hermetet, Gregory; Sadelain, Michel; Rivière, Isabelle

    2015-04-01

    The successful genetic engineering of patient T cells with γ-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the large-scale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10- to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice-grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks' yield in the bioreactor were higher by 3.2- to 7.3-fold, and 5.6- to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce γ-retroviral vector stocks scalable up to the commercialization phase.

  15. Large-scale Clinical-grade Retroviral Vector Production in a Fixed-Bed Bioreactor

    Science.gov (United States)

    Wang, Xiuyan; Olszewska, Malgorzata; Qu, Jinrong; Wasielewska, Teresa; Bartido, Shirley; Hermetet, Gregory; Sadelain, Michel

    2015-01-01

    The successful genetic engineering of patient T cells with γ-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the large-scale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10- to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice–grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks’ yield in the bioreactor were higher by 3.2- to 7.3-fold, and 5.6- to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce γ-retroviral vector stocks scalable up to the commercialization phase. PMID:25751502

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

    Science.gov (United States)

    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.

  17. Preliminary Study on Airlift Membran-Bioreactor%气升式膜-生物反应器的设计与应用

    Institute of Scientific and Technical Information of China (English)

    徐农; 邢卫红; 徐南平; 时钧

    2002-01-01

    A new type of membrane bioreactor named "airlift membrane-bioreactor" is discussed. For municipal wastewater reclamation, the preliminary study on airlift membrane-bioreactor shows its good performance such as higher flux and lower energy consumption. The airlift membrane-bioreactor is potentially applicable in bioengineering and environmental protection fields.

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

    Science.gov (United States)

    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.

    Science.gov (United States)

    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.

    Science.gov (United States)

    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. Bioreactor

    Science.gov (United States)

    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

  2. Ethanol production from whey in a membrane recycle bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Tin, C.S.F.; Mawson, A.J. (Massey Univ., Palmerston North (New Zealand). Dept. of Biotechnology)

    1993-01-01

    Ethanol production from sulphuric acid whey permeate by Kluyveromyces marxianus Y-113 was examined in a membrane recycle bioreactor. The system was operated with 100% cell recycle and at a steady-state with 10 g litre [sup -1] biomass. At rate constant D=0.44h[sup -1] almost complete utilization of 53g litre [sup -1] lactose was achieved with an ethanol productivity of 8.6g litre [sup -1]h[sup -1]. Increasing the inlet lactose concentration or dilution rate increased the ethanol productivity but at the expense of lactose utilization. Elevated biomass or ethanol concentrations markedly decreased the specific growth rate and specific ethanol production rate. (author)

  3. Membrane bio-reactors for decentralized wastewater treatment and reuse.

    Science.gov (United States)

    Meuler, S; Paris, S; Hackner, T

    2008-01-01

    Decentralized wastewater treatment is the key to sustainable water management because it facilitates effluent (and nutrient) reuse for irrigation or as service water in households. Membrane bioreactors (MBR) can produce effluents of bathing water quality. Septic tanks can be retrofitted to MBR units. Package MBR plants for wastewater or grey water treatment are also available. Systems for decentralized treatment and reuse of domestic wastewater or grey water are also feasible for hotels, condominiums and apartment or office complexes. This paper presents the effluent qualities of different decentralized MBR applications. The high effluent quality allows infiltration even in sensitive areas or reuse for irrigation, toilet flushing and cleaning proposes in households. Due to the reusability of treated water and the possibility to design the systems for carbon reduction only, these systems can ideally and easily serve to close water and nutrient loops. IWA Publishing 2008.

  4. Rheology of sludge in a complete retention membrane bioreactor.

    Science.gov (United States)

    Pollice, A; Giordano, C; Laera, G; Saturno, D; Mininni, G

    2006-07-01

    A rheological characterization of the sludge sampled from a complete retention membrane bioreactor was performed in order to correlate the apparent viscosity with the concentration of solids. The three most commonly adopted models were tested to select the one better fitting the experimental data. Ostwald model was choosen, and the relationship between the apparent viscosity and the shear rate was determined for mixed liquor suspended solids (MLSS) concentrations ranging between 9 and 25 g l(-1). Ostwald model parameters k and n were correlated with MLSS concentration, comparing linear, power, and exponential-power (only for k) laws in terms of R2 and Mean Root Square Error (MRSE). Both power and exponential-power functions provided good and comparable correlations for parameter k, while the linear relationship was much less accurate, especially at the highest solid concentrations. The parameter n was better modelled by a power function than by a linear one. Therefore two simulation models were proposed, both based on Ostwald's equation, where the two parameters k and n were expressed as functions of MLSS. Evaluation of energy consumption for mixing showed that the increase of solid concentration from 3 to 30 g l(-1) resulted in a limited increase in energy requirement (25-30 %). In real systems, where Reynolds numbers shift towards the turbulent regime, the increase of energy requirements for increasing solids concentration is even less pronounced. The thixotropy of membrane bioreactor sludge was also evaluated by measuring the rHa (reduced hysteresis area) and relating this parameter to the characteristics of the sludge growing within the reactor.

  5. Food industrial wastewater reuse by membrane bio-reactor

    Directory of Open Access Journals (Sweden)

    Patthanant Natpinit

    2007-11-01

    Full Text Available The objective of this investigation was to study the possibility and performance of treating food industrial wastewater by Membrane BioReactor (MBR. In addition, the effluent of MBR was treated by Reverse Osmosis system (RO to reuse in boiler or cooling tower. The membranes of hollow fiber type were filled in the aerobic tank with aerobe bacteria. The total area of membrane 6 units was 630 m2 so the flux of the operation was 0.25 m/d or 150 m3/d. The spiral wound RO was operated at 100 m3/d of influent and received 72 m3/d of permeate. The sludge volume (MLSS of MBR was maintained at 8,000-10,000 mg/l. The average COD and SS of MBR influent were 600 mg/l and 300 mg/l respectively. After treating by MBR, COD and SS of effluent were maintained at less than 100 mg/l and less than 10 mg/l respectively. In the same way, COD and SS of RO permeate were less than 10 mg/l and less than 5 mg/l respectively.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  9. Membrane fouling in pilot-scale membrane bioreactors (MBRs) treating municipal wastewater.

    Science.gov (United States)

    Kimura, Katsuki; Yamato, Nobuhiro; Yamamura, Hiroshi; Watanabe, Yoshimasa

    2005-08-15

    The main obstacle for wider use of membrane bioreactors (MBRs) for wastewater treatment is membrane fouling (i.e., deterioration of membrane permeability),which increases operating costs. For more efficient control of membrane fouling in MBRs, an understanding of the mechanisms of membrane fouling is important. However, there is a lack of information on membrane fouling in MBRs, especially information on features of components that are responsible for the fouling. We conducted a pilot-scale experiment using real municipal wastewater with three identical MBRs under different operating conditions. The results obtained in this study suggested that the food-microorganisms ratio (F/M) and membrane filtration flux were the important operating parameters that significantly influenced membrane fouling in MBRs. Neither concentrations of dissolved organic matter in the reactors nor viscosity of mixed liquor, which have been thought to have influences on fouling in MBRs, showed clear relationships with membrane fouling in this study. Organic substances that had caused the membrane fouling were desorbed from fouled membranes of the MBRs at the termination of the operation and were subjected to Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (NMR) analyses. These analyses revealed that the nature of the membrane foulant changes depending on F/M. It was shown that high F/M would make the foulant more proteinaceous. Carbohydrates were dominant in membrane foulants in this study, while features of humic substances were not apparent.

  10. Drinking Water Denitrification using Autotrophic Denitrifying Bacteria in a Fluidized Bed Bioreactor 

    Directory of Open Access Journals (Sweden)

    Abdolmotaleb Seid-mohammadi

    2013-02-01

    Full Text Available Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr. Results: We found that  the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98%  and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria.  However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water.  Conclusion: This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

  11. A novel In-situ Enzymatic Cleaning Method for Reducing Membrane Fouling in Membrane Bioreactors (MBRs

    Directory of Open Access Journals (Sweden)

    M. R. Bilad

    2016-05-01

    Full Text Available A novel in-situ enzymatic cleaning method was developed for fouling control in membrane bioreactors (MBRs. It is achieved by bringing the required enzymes near the membrane surface by pulling the enzymes to a magnetic membrane (MM surface by means of magnetic forces, exactly where the cleaning is required. To achieve this, the enzyme was coupled to a magnetic nanoparticle (MNP and the membrane it self was loaded with MNP. The magnetic activity was turned by means of an external permanent magnet. The effectiveness of concept was tested in a submerged membrane filtration using the model enzyme-substrate of Bacillus subitilis xylanase-arabinoxylan. The MM had almost similar properties compared to the unloaded ones, except for its well distributed MNPs. The enzyme was stable during coupling conditions and the presence of coupling could be detected using a high-performance anion-exchange chromatography (HPAEC analysis and Fourier transform infrared spectroscopy (FTIR. The system facilitated an in-situ enzymatic cleaning and could be effectively applied for control fouling in membrane bioreactors (MBRs.

  12. Modeling the microbial growth and temperature profile in a fixed-bed bioreactor.

    Science.gov (United States)

    da Silveira, Christian L; Mazutti, Marcio A; Salau, Nina P G

    2014-10-01

    Aiming to scale up and apply control and optimization strategies, currently is required the development of accurate plant models to forecast the process nonlinear dynamics. In this work, a mathematical model to predict the growth of the Kluyveromyces marxianus and temperature profile in a fixed-bed bioreactor for solid-state fermentation using sugarcane bagasse as substrate was built up. A parameter estimation technique was performed to fit the mathematical model to the experimental data. The estimated parameters and the model fitness were evaluated with statistical analyses. The results have shown the estimated parameters significance, with 95 % confidence intervals, and the good quality of process model to reproduce the experimental data.

  13. Utilization of molasses and akalona hydrolyzate for continuous glycerol production in a packed bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, N.A.; Magdy, Yehia H. [El-Minia Univ., Chemical Engineering Dept., El-Minia (Egypt)

    1998-12-31

    Continuous glycerol fermentation of a by-product cane sugar molasses and wheat milling residues (akalona) was studied using sulfite as a combining agent with the aldehyde. Thus, a local yeast Saccharomyces cerevisiae could be used under anaerobic conditions instead of glycerol production microorganisms (osmophilic yeast`s) which need essentially aerobic conditions. The processes were performed in a vertical packed-bed reactor with yeast cells immobilized in agar gel. The influence of the dilution rate on the performance of the bioreactor was studied. The substrate and product concentration profiles along the column height are presented. A kinetic study has been used to identify the rate controlling step(s). (Author)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. Clofibric acid and gemfibrozil removal in membrane bioreactors.

    Science.gov (United States)

    Gutierrez-Macias, Tania; Nacheva, Petia Mijaylova

    2015-01-01

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

  17. Comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, Fausto; Sint Annaland, van Martin; Kuipers, J.A.M.

    2009-01-01

    In this work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, have been compared for the reforming of methane for the production of ultra-pure hydrogen. Using detailed theoretical models, the required membrane area to reach a given conversi

  18. Theoretical comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, Fausto; Sint Annaland, van Martin; Kuipers, J.A.M.

    2010-01-01

    In this theoretical work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming. Using detailed theoretical models, the required membrane area to reach a given conversion

  19. An analysis of a trickle-bed bioreactor: Carbon disulfide removal

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, R.; Revah, S.; Viveros-Garcia, T. [Univ. Autonoma Metropolitana-Iztapalapa (Mexico). Dept. de Ingenieria de Procesos e Hidraulica

    1999-04-05

    An analysis of the local processes occurring in a trickle-bed bioreactor (TBB) with a first-order bioreaction shows that the identification of the TBB operating regime requires knowledge of the substrate concentration in the liquid phase. If the substrate liquid concentration is close to 0, the rate-controlling step is mass transfer at the gas-liquid interface; when it is close to the value in equilibrium with the gas phase, the controlling step is the phenomena occurring in the biofilm, CS{sub 2} removal rate data obtained in a TBB with a Thiobacilii consortia biofilm are analyzed to obtain the mass transfer and kinetic parameters, and to show that the bioreactor operates in a regime mainly controlled by mass transfer. A TBB model with two experimentally determined parameters is developed and used to show how the bioreactor size depends on the rate-limiting step, the absorption factor, the substrate fractional conversion, and on the gas and liquid contact pattern. Under certain conditions, the TBB size is independent of the flowing phases` contact pattern. The model effectively describes substrate gas and liquid concentration data for mass transfer and biodegradation rate controlled processes.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  3. Economic analysis of fuel ethanol production from corn starch using fluidized-bed bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, M.S.; Davison, B.H.; Nghiem, N.P. [Oak Ridge National Laboratory (United States). Chemical Technology Division; Taylor, F. [USDA, Wyndmoor, PA (United States). Eastern Regional Research

    2000-11-01

    The economics of fuel ethanol production from dry-milled corn starch were studied in fluidized-bed bioreactors (FBRs) using immobilized biocatalysts. Glucoamylase immobilized on porous diatomaceous earth was used for hydrolysis of the starch to glucose in a packed-bed reactor. The fermentation of glucose to ethanol was carried out in FBRs using Zymomonas mobilis immobilized in {kappa}-carrageenan beads. Volumetric ethanol productivities of up to 24 g/l h were achieved in non-optimized laboratory-scale systems. For a 15 million gal/yr ethanol plant, an economic analysis of this process was performed with Aspen Plus (Aspen Technology, Cambridge, MA) process simulation software. The analysis shows that an operating cost savings in the range of 1.1-3.1 cents/gal can be realized by using the FBR technology. (author)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. A REVIEW ON SEWAGE TREATMENT AND POLISHING USING MOVING BED BIOREACTOR (MBBR

    Directory of Open Access Journals (Sweden)

    JAMAL ALI KAWAN

    2016-08-01

    Full Text Available Effluent treatment and polishing using moving bed bioreactors (MBBRs are advanced technique in biological treatment operations become increasing widely and popular use all over the world to treat various types of effluents with very different operating status. It is a combination of two separate processes suspended and attached growth systems for the treatment in order to minimize the concentrations of the contaminated parameters at the required level for reuse or final destination. The MBBR has been proved to be effective in great removing biochemical oxygen demand (BOD and chemical oxygen demand (COD with nutrients (N and P from the effluent stream simultaneously. It provides additional capacity of wastewater treatment technology with high treatment efficiency; low capital, operational, maintenance and replacement cost; single reliable and robust operation procedure. This process can be used for new sewage treatment works or for modifying (upgrading existing wastewater treatment plants as it is efficient, compact and easy to operate. The efficiency of MBBR depends on the filling percent of biofilm carriers to be provided inside the tank, surface area of the biocarrier, diffused aeration supply and the organic loading. The aim of this paper is reviewing the sewage treatment and polishing using moving bed bioreactor MBB technology as an alternative and successful method. It presents the advantages of the MBBR compared to conventional waste water treatment. The review also includes many relevant researches carried out at the laboratory andpilot scales plants that could improve these systems by enhancing performance and reducing costs.

  7. Laboratory-scale biofiltration of acrylonitrile by Rhodococcus rhodochrous DAP 96622 in a trickling bed bioreactor.

    Science.gov (United States)

    Zhang, Jie; Pierce, George E

    2009-07-01

    Acrylonitrile (ACN), a volatile component of the waste generated during the production of acrylamide, also is often associated with aromatic contaminants such as toluene and styrene. Biofiltration, considered an effective technique for the treatment of volatile hydrocarbons, has not been used to treat volatile nitriles. An experimental laboratory-scale trickling bed bioreactor using cells of Rhodococcus rhodochrous DAP 96622 supported on granular activated carbon (GAC) was developed and evaluated to assess the ability of biofiltration to treat ACN. In addition to following the course of treatability of ACN, kinetics of ACN biodegradation during both recycle batch and open modes of operation by immobilized and free cells were evaluated. For fed-batch mode bioreactor with immobilized cells, almost complete ACN removal (>95%) was achieved at a flow rate of 0.1 microl/min ACN and 0.8 microl/min toluene (TOL) (for comparative purposes this is equivalent to 6.9 mg l(-1) h(-1) ACN and 83.52 mg l(-1) h(-1) TOL). In a single-pass mode bioreactor with immobilized cells, at ACN inlet loads of 100-200 mg l(-1) h(-1) and TOL inlet load of approximately 400 mg l(-1) h(-1), with empty bed retention time (EBRT) of 8 min, ACN removal efficiency was approximately 90%. The three-dimensional structure and characteristics of the biofilm were investigated using confocal scanning laser microscopy (CSLM). CLSM images revealed a robust and heterogeneous biofilm, with microcolonies interspersed with voids and channels. Analysis of the precise measurement of biofilm characteristics using COMSTAT agreed with the assumption that both biomass and biofilm thickness increased along the carbon column depth.

  8. Bio-Gas production from municipal sludge waste using anaerobic membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Lee, S.

    2009-07-01

    A laboratory scale anaerobic membrane bioreactor (AnMBR) system for the bio-methane gas production was operated for 60 days with municipal sludge wastes as a sole carbon source. The AnMRR system utilized the external cross-flow membrane module and was equipped with on-line data acquisition which enables continuous monitoring of the performance of both bioreactor and membrane through the analyses of pH, temperature, gas production; permeate flow rate, and transmembrane pressure (TMP). Such a configuration also provides an efficient tool to study rapid variations of monitoring membrane pressure (TMP). (Author)

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

    OpenAIRE

    Anthony G. Fane; Bing Wu

    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 inf...

  10. Effect of components in activated sludge liquor on membrane fouling in a submerged membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    YU Shui-li; ZHAO Fang-bo; ZHANG Xiao-hui; JING Guo-lin; ZHEN Xiang-hua

    2006-01-01

    By a membrane bioreactor with a settle tank in long-term operation and batch experiments, the effects of flocs, soluble microorganism products (SMPs) and metal ions in activated sludge liquor on membrane fouling were investigated. The results showed that foulants absorbed each other and formed a fouling layer as a "second membrane" influencing the permeability of the membrane.The "gel layer" caused by SMPs and "cake layer" by flocs showed great differences in morphology by analysis of scanning electron microscope and atomic force microscope. The "gel layer" was more compact and of poor permeability. When the membrane flux was MPa/h). SMPs played very important roles on membrane fouling. In the bu1king sludge, with SMPs increasing, the rate of membrane fouling (0.0132 MPa/h) was faster. While after flocculation of the SMPs, the rate of fouling decreased to 0.0034 MPa/h. Flocs could keep holes in their overlaps. They could alleviate membrane fouling by preventing the SMPs directly attaching on membrane surface.

  11. Modeling of hydrodynamics in hollow fiber membrane bioreactor for mammalian cells cultivation

    Directory of Open Access Journals (Sweden)

    N. V. Menshutina

    2016-01-01

    Full Text Available The mathematical modelling in CFD-packages are powerfull instrument for design and calculation of any engineering tasks. CFD-package contains the set of programs that allow to model the different objects behavior based on the mathematical lows. ANSYS Fluent are widely used for modelling of biotechnological and chemical-technological processes. This package is convenient to describe their hydrodynamics. As cell cultivation is one of the actual scientific direction in modern biotechnology ANSYS Fluent was used to create the model of hollow fiber membrane bioreactor. The fibers are hollow cylindrical membrane to be used for cell cultivation. The criterion of process effectiveness for cell growth is full filling of the membrane surface by cells in the bioreactor. While the cell growth the fiber permeability is decreased which effects to feed flow through membrane pores. The specific feature of this process is to ensure such feed flow to deliver the optimal nutrition for the cells on the external membrane surface. The velocity distribution inside the fiber and in all bioreactor as a whole has been calculated based on mass an impulse conservation equations taking into account the mathematical model assumptions. The hydrodynamics analysis in hollow fiber membrane bioreactor is described by the three-dimensional model created in ANSYS Fluent. The specific features of one membrane model are considered and for whole bioreactor too.

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

    Science.gov (United States)

    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.

  13. The efficiency of a membrane bioreactor in drinking water denitrification

    Directory of Open Access Journals (Sweden)

    Petrovič Aleksandra

    2015-01-01

    Full Text Available The membrane bioreactor (MBR system was investigated regarding its nitrate removal capacity from drinking water. The performance of a pilot-scale MBR was tested, depending on the operational parameters, using sucrose as a carbon source. Drinking water from the source was introduced into the reactor in order to study the influence of flow-rate on the nitrate removal and denitrification efficiency of drinking water. The content of the nitrate was around 70 mg/L and the C/N ratio was 3:1. Nitrate removal efficiencies above 90% were obtained by flow-rates lower than 4.8 L/h. The specific denitrification rates varied between 0.02 and 0.16 g/L NO3/ (g/L MLSS•d. The efficiencies and nitrate removal were noticeably affected by the flow-rate and hydraulic retention times. At the maximum flow-rate of 10.2 L/h still 68% of the nitrate had been removed, whilst the highest specific denitrification rate was achieved at 0.2738 g/L NO3/ (g/L MLSS•d. The maximum reactor removal capacity was calculated at 8.75 g NO3/m3•h.

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

    Science.gov (United States)

    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.

  15. Simultaneous carbon, nitrogen and phosphorous removal from municipal wastewater in a circulating fluidized bed bioreactor.

    Science.gov (United States)

    Patel, Ajay; Zhu, Jesse; Nakhla, George

    2006-11-01

    In this study, the performance of the circulating fluidized bed bioreactor (CFBB) with anoxic and aerobic beds and employing lava rock as a carrier media for the simultaneous removal of carbon, nitrogen and phosphorus from municipal wastewater at an empty bed contact time (EBCT) of 0.82 h was discussed. The CFBB was operated without and with bioparticles' recirculation between the anoxic and aerobic bed for 260 and 110 d respectively. Without particles' recirculation, the CFBB was able to achieve carbon (C), total nitrogen (N) and phosphorous (P) removal efficiencies of 94%, 80% and 65% respectively, whereas with bioparticles' recirculation, 91%, 78% and 85% removals of C, N and P were achieved. The CFBB was operated at long sludge retention time (SRT) of 45-50 d, and achieved a sludge yield of 0.12-0.135 g VSS g COD(-1). A dynamic stress study of the CFBB was carried out at varying feed flow rates and influent ammonia concentrations to determine response to shock loadings. The CFBB responded favourably in terms of TSS and COD removal to quadrupling of the feed flow rate. However, nitrification was more sensitive to hydraulic shock loadings than to doubling of influent nitrogen loading.

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

    Science.gov (United States)

    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 (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).

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

    Science.gov (United States)

    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.

  18. Biodegradation of formaldehyde from contaminated air using a laboratory scale static-bed bioreactor

    Directory of Open Access Journals (Sweden)

    Yaghoub Hajizadeh

    2014-01-01

    Full Text Available Aims: The objective of the present study was to evaluate the performance of an aerobic fixed-bed bioreactor (FBR enriched with microorganisms of sewage sludge in biodegradation of formaldehyde in air stream with various retention times and airflow rates in laboratory scale. Materials and Methods: An aerobic biofilter 60 cm in height and 14 cm internal diameter made of steel was constructed and packed with a mixture of pumice and compost as a medium and utilized in this study. The microorganism′s growth, which is derived from the sludge of a municipal wastewater treatment plant, was initiated by adding nutrient. During the first few days of run, the airflow containing different concentrations of formaldehyde (from 24 ± 3 to 224 ± 5 mg/m 3 was introduced to the reactor to ensure biological adaptation. Sampling was performed through a series of two impingers containing adsorbent, and analyzed by chromotropic acid assay using DR-5000. Results: The maximum removal and elimination capacity of formaldehyde was yielded at 0.48 ± 0.06 g/m 3 /h inlet loading rate and 180 s of empty bed retention time (EBRT. These values for stabilized days were almost 88% and 0.42 g/m 3 /h, respectively. Conclusion: The results showed that by increasing the inlet concentration of formaldehyde and reducing the EBRT, the formaldehyde removal capacity of the system decreases. Aerobic bioreactor with appropriate bed volume and compatible with inlet pollutant mass flow rate in optimum retention time will admissibly degrade and reduce the formaldehyde concentration from contaminated gas phase, such as gases produced in municipal wastewater treatment facilities.

  19. Biological nutrient removal from leachate using a pilot liquid-solid circulating fluidized bed bioreactor (LSCFB).

    Science.gov (United States)

    Eldyasti, Ahmed; Chowdhury, Nabin; Nakhla, George; Zhu, Jesse

    2010-09-15

    Biological treatment of landfill leachate is a concern due to toxicity, high ammonia, low biodegradable organic matter concentrations, and low carbon-to-nitrogen ratio. To study the reliability and commercial viability of leachate treatment using an integrated liquid-solid circulating fluidized bed bioreactor (LSCFB), a pilot-scale LSCFB was established at the Adelaide Pollution Control Plant, London, Ontario, Canada. Anoxic and aerobic columns were used to optimize carbon and nutrient removal capability from leachate using 600 microm lava rock with a total porosity of 61%, at empty bed contact times (EBCTs) of 0.55, 0.49, and 0.41 d. The LSCFB achieved COD, nitrogen, and phosphorus removal efficiencies of 85%, 80%, and 70%, respectively at a low carbon-to-nitrogen ratio of 3:1 and nutrients loading rates of 2.15 kg COD/(m(3) d), 0.70 kg N/(m(3) d), and 0.014 kg P/(m(3) d), as compared with 60-77% COD and 70-79% nitrogen removal efficiencies achieved by upflow anaerobic sludge blanket (UASB) and moving bed bioreactor (MBBR), respectively. The LSCFB effluent characterized by

  20. Effects of salinity on the characteristics of biomass and membrane fouling in membrane bioreactors

    DEFF Research Database (Denmark)

    Jang, D.; Hwang, Yuhoon; Shin, H.

    2013-01-01

    ; and the changes in microbial composition in turn have affected the performance of the MBRs. Membrane fouling was accelerated by the increased pore blocking resistance at higher salt concentrations. Analysis results of physicochemical and biological characteristics of biomass (EPS, floc size, zeta potential......This study investigated the effects of high salinity on the performance and membrane fouling of membrane bioreactor (MBR) with saline wastewater. Synthetic wastewaters containing 5-20g/L salts (NaCl) were treated in identical lab-scale (7L) MBRs monitoring removals of dissolved organic carbon (DOC......) and ammonia. Increase in salt concentrations did not significantly change the removal efficiency of DOC in the MBRs. However, the ammonia removals decreased from 87% to 46% with increasing salt concentrations. PCR-DGGE analysis indicated changes in the microbial communities' composition due to high salinity...

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

    Science.gov (United States)

    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.

  2. Characterization of membrane foulants at ambient temperature anaerobic membrane bioreactor treating low-strength industrial wastewater

    DEFF Research Database (Denmark)

    Zarebska, Agata; Kjerstadius, Hamse; Petrinic, Irena

    2016-01-01

    with anaerobic biological treatment at low temperature could not only reduce the operational cost of AD, but also alleviate environmental problems. However, at low temperature the AnMBR may suffer more fouling due to the increased extracellular polymeric substances production excreted by bacteria hampering......The large volume of industrial low-strength wastewaters has a potential for biogas production through conventional anaerobic digestion (AD), limited though by the need of heating and concentrating of the wastewaters. The use of anaerobic membrane bioreactor (AnMBR) combining membrane filtration...... the application of the process for the industrial wastewater treatment. In order to solve or reduce the fouling problem it is necessary to have a good insight into the processes that take place both on and in the membrane pores during filtration. Therefore, the objective of this study is to contribute to a better...

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Insect cell entrapment, growth and recovering using a single-use fixed-bed bioreactor. Scaling up and recombinant protein production.

    Science.gov (United States)

    Ventini-Monteiro, D; Dubois, S; Astray, R M; Castillo, J; Pereira, C A

    2015-12-20

    Insect cells are largely used for industrial production of vaccines, viral vectors and recombinant proteins as well as in research and development as an important tool for biology and bioprocess studies. They grow in suspension and are semi-adherent cells. Among the cell culture systems enabling scalable bioprocess the single-use fixed-bed iCELLis(®) bioreactors offer great advantages. We have established the conditions for Drosophila melanogaster Schneider 2 (S2) and Spodoptera frugiperda (Sf9) cells entrapment into the fixed-bed, cell growth and recover from the fixed-bed once high cell densities were attained. Our established protocol allowed these cells, at a cell seeding of 2×1E5 cells/microfiber carriers (MC) (3.5×1E6cells/mL; 1.7×1E4cells/cm(2)), to grow inside a 4m(2)/200mL fixed-bed attaining a concentration of 5.3×1E6 cells/MC (9.5×1E7cells/mL; 4.7×1E5 cells/cm(2)) for S2 cells or 4.6×1E6 cells/MC (8×1E7cells/mL; 4.1×1E5cells/cm(2)) for Sf9 cells. By washing the fixed-bed, entrapped cells could then be recovered from the fixed-bed at a high rate (>85%) with high viability (>95%) by increasing the agitation to 1200/1500rpm. Although the cell yields in the fixed-bed bioreactor were comparable to those obtained in a stirred tank (respectively, 1.3×1E10 and 2.5×1E10 total cells), S2 cells stably transfected with a cDNA coding for the rabies virus glycoprotein (RVGP) showed a 30% higher preserved rRVGP production (2.5±0.1 and 1.9±0.1μg/1E7 cells), as evidenced by a conformational ELISA evaluation. These findings demonstrate not only the possibility to entrap, cultivate to high densities and recover insect cells using a single-use fixed-bed bioreactor, but also that this system provides suitable physiological conditions for the entrapped cells to produce a cell membrane associated recombinant protein with higher specific biological activity as compared to classical suspension cell cultures.

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

    Science.gov (United States)

    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.

  6. Relationship between sludge settleability and membrane fouling in a membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    SUN Yujiao; WANG Yong; HUANG Xia

    2007-01-01

    The evolution of activated sludge settleability and its relationship to membrane fouling in a submerged mem brane bioreactor were studied at a lab-scale equipment fed with synthetic wastewater.It was found that sludge volume index(SVI)gradually increased and the sludge settleability was reduced,which was caused by the propagation of filamentous bacteria.With increasing SVI,the average increasing rate of trans-membrane pressure increased.the stable filtration period was shortened.and the two stages(smooth stage and accelerating stage)of the trans-membrane pressure were more obvious.At the same time,the increasing rate of trans-membrane pressure at the smooth stage decreased and the rate at the accelerating stage increased with SVI,respectively.The observation by using scanning electronic microscopes showed the cake layer with loose structure and large thickness formed on the membrane surface due to the appearance of filamentous bacteria and high SVI in sludge.Influence of the sludge settleability on the trans-membrane pressure was related to the structure and thickness of the cake layer on the membrane.

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

    Directory of Open Access Journals (Sweden)

    Oliver Terna Iorhemen

    2016-06-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  9. Fouling of inorganic membrane and flux enhancement in membrane-coupled anaerobic bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S.H.; Kang, I.J.; Lee, C.H. [Seoul National Univ. (Korea, Republic of). Dept. of Chemical Technology

    1999-03-01

    The fouling mechanism of an inorganic membrane was studied during the operation of a membrane-coupled anaerobic bioreactor (MCAB) when alcohol distillery wastewater was used as a digester feed. It was observed that the fouling mechanism of an inorganic membrane was significantly different from that of conventional membrane filtration processes. The main foulant was identified to be an inorganic precipitate, struvite (MgNH{sub 4}PO{sub 4}{center_dot}6H{sub 2}O), rather than anaerobic microbial flocs. Struvite appears to be precipitated not only on the membrane surface but also inside the membrane pores. The amount of struvite generated during the bioreaction was estimated to be about 2 g/L alcohol distillery wastewater. The inorganic foulant was not easily removed by general physical cleaning such as depressurization, lumen flushing, and backflushing. Based on these findings, the membrane fouling was alleviated and thus flux was enhanced by adopting a backfeeding mode which has dual purpose of feeding and backflushing with particle-free acidic wastewater used as the feed for anaerobic digestion.

  10. Characterization of biofoulants illustrates different membrane fouling mechanisms for aerobic and anaerobic membrane bioreactors

    KAUST Repository

    Xiong, Yanghui

    2015-11-17

    This study compares the membrane fouling mechanisms of aerobic (AeMBR) and anaerobic membrane bioreactors (AnMBR) of the same reactor configuration at similar operating conditions. Although both the AeMBR and AnMBR achieved more than 90% COD removal efficiency, the fouling mechanisms were different. Molecular weight (MW) fingerprint profiles showed that a majority of fragments in anaerobic soluble microbial products (SMP) were retained by the membrane and some fragments were present in both SMP and in soluble extracellular polymeric substances (EPS), suggesting that the physical retention of SMP components contributed to the AnMBR membrane fouling. One of the dominant fragments was comprised of glycoliproprotein (size 630-640 kD) and correlated in abundance in AnMBR-EPS with the extent of anaerobic membrane fouling. In contrast, all detected AeMBR-SMP fragments permeated through the membrane. Aerobic SMP and soluble EPS also showed very different fingerprinting profiles. A large amount of adenosine triphosphate was present in the AeMBR-EPS, suggesting that microbial activity arising from certain bacterial populations, such as unclassified Comamonadaceae and unclassified Chitinophagaceae, may play a role in aerobic membrane fouling. This study underlines the differences in fouling mechanisms between AeMBR and AnMBR systems and can be applied to facilitate the development of appropriate fouling control strategies.

  11. Effect of low dosages of powdered activated carbon on membrane bioreactor performance

    NARCIS (Netherlands)

    Remy, M.J.J.; Temmink, H.; Rulkens, W.H.

    2012-01-01

    Previous research has demonstrated that powdered activated carbon (PAC), when applied at very low dosages and long SRTs, reduces membrane fouling in membrane bioreactors (MBRs). This effect was related to the formation of stronger sludge flocs, which are less sensitive to shear. In this contribution

  12. Fluidized-bed adsorption bioreactor for the treatment of groundwater contaminated with solvents at low concentration

    Energy Technology Data Exchange (ETDEWEB)

    Miyares, P.H.; Teeter, C.V.; Martel, C.J.

    1999-01-01

    Volatile organic compounds (VOCs) are a major source of water contamination in the US. They pose a threat to the environment and are a potential hazard to human health. Trichloroethylene (TCE) is the most common of these pollutants. TCE is usually remediated through pumping and treating it, using either air stripping or granular activated carbon. Bioremediation is an alternative treatment that uses microbes to convert hazardous substances into nonhazardous compounds. A fluidized bed adsorption bioreactor is examined here for the treatment of groundwater contaminated at low concentrations. This pilot study showed that the packed adsorbent bed could be loaded in approximately 36 hours at a flow rate of 120 mL/min. The remediation phase of the process took approximately 13 days. The reduction in the TCE concentration in the sorbent during each round indicated that it was being remediated by the microbiological process. Areas that need to be improved are the rate of remediation and the loading capacity of the adsorption beds. Currently, each complete cycle of loading and remediating requires 2 weeks while only mineralizing 58 mg of TCE per column.

  13. Membrane bioreactor sludge rheology at different solid retention times.

    Science.gov (United States)

    Laera, G; Giordano, C; Pollice, A; Saturno, D; Mininni, G

    2007-10-01

    Rheological characterization is of crucial importance in sludge management both in terms of biomass dewatering and stabilization properties and in terms of design parameters for sludge handling operations. The sludge retention time (SRT) has a significant influence on biomass properties in biological wastewater treatment systems and in particular in membrane bioreactors (MBRs). The aim of this work is to compare the rheological behaviour of the biomass in a MBR operated under different SRTs. A bench-scale MBR was operated for 4 years under the same conditions except for the SRT, which ranged from 20 days to complete sludge retention. The rheological properties were measured over time and the apparent viscosity was correlated with the concentration of solid material when equilibrium conditions were reached and maintained. The three models most commonly adopted for rheological simulations were evaluated and compared in terms of their parameters. Then, steady-state average values of these parameters were related to the equilibrium biomass concentration (MLSS). The models were tested to select the one better fitting the experimental data in terms of mean root square error (MRSE). The relationship between the apparent viscosity and the shear rate, as a function of solid concentration, was determined and is proposed here. Statistical analysis showed that, in general, the Bingham model provided slightly better results than the Ostwald one. However, considering that a strong correlation between the two parameters of the Ostwald model was found for all the SRTs tested, both in the transient growth phases and under steady-state conditions, this model might be used more conveniently. This feature suggests that the latter model is easier to be used for the determination of the sludge apparent viscosity.

  14. Continuous Ethanol Production Using Immobilized-Cell/Enzyme Biocatalysts in Fluidized-Bed Bioreactor (FBR)

    Energy Technology Data Exchange (ETDEWEB)

    Nghiem, NP

    2003-11-16

    The immobilized-cell fluidized-bed bioreactor (FBR) was developed at Oak Ridge National Laboratory (ORNL). Previous studies at ORNL using immobilized Zymomonas mobilis in FBR at both laboratory and demonstration scale (4-in-ID by 20-ft-tall) have shown that the system was more than 50 times as productive as industrial benchmarks (batch and fed-batch free cell fermentations for ethanol production from glucose). Economic analysis showed that a continuous process employing the FBR technology to produce ethanol from corn-derived glucose would offer savings of three to six cents per gallon of ethanol compared to a typical batch process. The application of the FBR technology for ethanol production was extended to investigate more complex feedstocks, which included starch and lignocellulosic-derived mixed sugars. Economic analysis and mathematical modeling of the reactor were included in the investigation. This report summarizes the results of these extensive studies.

  15. Laccase-mediated Remazol Brilliant Blue R decolorization in a fixed-bed bioreactor.

    Science.gov (United States)

    Palmieri, Gianna; Giardina, Paola; Sannia, Giovanni

    2005-01-01

    A crude laccase mixture preparation from Pleurotus ostreatus cultures supplemented with copper and ferulic acid was used to decolorize the anthraquinonic dye Remazol Brilliant Blue R (RBBR). Performance of this enzymatic system was tested, and a maximum of 70% decolorization was achievable under optimal conditions. The crude preparation was immobilized by entrapment in copper alginate beads attaining 65% yield of laccase activity. Stability of the immobilized laccases was remarkably increased in comparison with that of the free enzyme preparation. Efficiency of the immobilized system was evaluated during stepwise dye additions in batch operations. Under the best conditions, 70% RBBR decolorization was achieved even after 20 cycles, although decolorization time exponentially increased after the 10th cycle. Different fixed-bed bioreactors were prepared and analyzed in continuous decolorization processes. The best performance was obtained by decreasing the amount of enzyme loaded and by improving laccase retention using chitosan-coated alginate beads.

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

    Science.gov (United States)

    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.

  17. Production of butyric acid from glucose and xylose with immobilized cells of Clostridium tyrobutyricum in a fibrous-bed bioreactor.

    Science.gov (United States)

    Jiang, Ling; Wang, Jufang; Liang, Shizhong; Wang, Xiaoning; Cen, Peilin; Xu, Zhinan

    2010-01-01

    Butyric acid has many applications in chemical, food, and pharmaceutical industries. In the present study, Clostridium tyrobutyricum ATCC 25755 was immobilized in a fibrous-bed bioreactor to evaluate the performance of butyrate production from glucose and xylose. The results showed that the final concentration and yield of butyric acid were 13.70 and 0.46 g g(-1), respectively, in batch fermentation when 30 g L(-1) glucose was introduced into the bioreactor. Furthermore, high concentration 10.10 g L(-1) and yield 0.40 g g(-1) of butyric acid were obtained with 25 g L(-1) xylose as the carbon source. The immobilized cells of C. tyrobutyricum ensured similar productivity and yield from repeated batch fermentation. In the fed-batch fermentation, the final concentration of butyric acid was further improved to 24.88 g L(-1) with one suitable glucose feeding in the fibrous-bed bioreactor. C. tyrobutyricum immobilized in the fibrous-bed bioreactor would provide an economically viable fermentation process to convert the reducing sugars derived from plant biomass into the final bulk chemical (butyric acid).

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Effect of macroporous adsorption resin-membrane bioreactor hybrid system against fouling for municipal wastewater treatment.

    Science.gov (United States)

    Chen, Weiwei; Luo, Jing; Cao, Ruyi; Li, Yuting; Liu, Jinrong

    2017-01-01

    Membrane bioreactor (MBR) displays significant advantages in effluent quality, sludge production, footprint, and operation. However, membrane fouling limits the application of MBR. This study investigated membrane fouling in a macroporous adsorption resin-membrane bioreactor hybrid system established by adding macroporous adsorption resin (MAR) into MBR. MAR addition increased the critical flux by 27.97%, indicating that membrane fouling was successfully mitigated. Consequently, comparative experiments were designed to analyze the pathway. MAR addition mitigated external fouling development and improved mixed liquor characteristics, thereby mitigating gel layer formation and sludge floc deposition on the membrane surface. MAR effectively reduced the supernatant viscosity and dissolved COD by adsorbing soluble microbial products. Sludge production decreased because the sludge activity in MAR-MBR was inhibited. The fouled MAR could be regenerated effectively by deionized water and chemical cleaning. This work demonstrated the feasibility of using MAR-MBR to mitigate fouling in municipal wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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. Comparative modeling of biological nutrient removal from landfill leachate using a circulating fluidized bed bioreactor (CFBBR).

    Science.gov (United States)

    Eldyasti, Ahmed; Andalib, Mehran; Hafez, Hisham; Nakhla, George; Zhu, Jesse

    2011-03-15

    Steady state operational data from a pilot scale circulating fluidized bed bioreactor (CFBBR) during biological treatment of landfill leachate, at empty bed contact times (EBCTs) of 0.49, and 0.41 d and volumetric nutrients loading rates of 2.2-2.6 kg COD/(m(3)d), 0.7-0.8 kg N/(m(3)d), and 0.014-0.016 kg P/(m(3)d), was used to calibrate and compare developed process models in BioWin(®) and AQUIFAS(®). BioWin(®) and AQUIFAS(®) were both capable of predicting most of the performance parameters such as effluent TKN, NH(4)-N, NO(3)-N, TP, PO(4)-P, TSS, and VSS with an average percentage error (APE) of 0-20%. BioWin(®) underpredicted the effluent BOD and SBOD values for various runs by 80% while AQUIFAS(®) predicted effluent BOD and SBOD with an APE of 50%. Although both calibrated models, confirmed the advantages of the CFBBR technology in treating the leachate of high volumetric loading and low biomass yields due to the long solid retention time (SRT), both BioWin(®) and AQUIFAS(®) predicted the total biomass and SRT of CFBBR based on active biomass only, whereas in the CFBBR runs both active as well as inactive biomass accumulated.

  2. Gluconic acid production in bioreactor with immobilized glucose oxidase plus catalase on polymer membrane adjacent to anion-exchange membrane.

    Science.gov (United States)

    Godjevargova, Tzonka; Dayal, Rajeshwar; Turmanova, Sevdalina

    2004-10-20

    Gluconic acid was obtained in the permeate side of the bioreactor with glucose oxidase (GOD) immobilized onto anion-exchange membrane (AEM) of low-density polyethylene grafted with 4-vinylpiridine. The electric resistance of the anion-exchange membranes was increased after the enzyme immobilization on the membrane. The gluconic acid productions were relatively low with the GOD immobilized by any method on the AEM. To increase the enzyme reaction efficiency, GOD was immobilized on membrane of AN copolymer (PAN) adjacent to an anion-exchange membrane in bioreactor. Uses of anion-exchange membrane led to selective removal of the gluconic acid from the glucose solution and reduce the gluconic acid inhibition. The amount of gluconic acid obtained in the permeate side of the bioreactor with the GOD immobilized on the PAN membrane adjacent to the AEM under electrodialysis was about 30 times higher than that obtained with enzyme directly bound to the AEM. The optimal substrate concentration in the feed side was found to be about 1 g/l. Further experiments were carried out with the co-immobilized GOD plus Catalase (CAT) on the PAN membrane adjacent to the AEM to improve the efficiency of the immobilize system. The yield of this process was at least 95%. The storage stability of the co-immobilized GOD and CAT was studied (lost 20% of initial activity for 90 d). The results obtained clearly showed the higher potential of the dual membrane bioreactor with GOD plus CAT bound to ultrafiltration polymer membrane adjacent to the AEM. Storage stability of GOD activity in GOD plus CAT immobilized on PAN//AEM membranes and on AEM.

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Influence of relaxation modes on membrane fouling in submerged membrane bioreactor for domestic wastewater treatment.

    Science.gov (United States)

    Habib, Rasikh; Asif, Muhammad Bilal; Iftekhar, Sidra; Khan, Zahiruddin; Gurung, Khum; Srivastava, Varsha; Sillanpää, Mika

    2017-08-01

    Relaxation and backwashing have become an integral part of membrane bioreactor (MBR) operations for fouling control. This study was carried out on real municipal wastewater to evaluate the influence of different operational strategies on membrane fouling at equivalent water yield. Four relaxation modes (MBR10+0, MBR10+1, MBR10+1.5 and MBR10+2) were tested to analyze membrane fouling behavior. For the optimization of relaxation modes, fouling rate in terms of trans-membrane pressure, hydraulic resistances and characteristics of fouling fractions were analyzed. It has been observed that cake layer resistance was minimum in MBR10+1.5 but pore blockage resistance was increased in all relaxation modes. Moreover, high instantaneous flux contributed significantly to fouling rate at the initial stage of MBR operations. Relaxation modes were also efficient in removing irreversible fouling to some extent. Under all relaxation modes, COD removal efficiency ranged from 92 to 96.5%. Ammonium and TP removal were on the lower side due to the short solids and hydraulic retention time. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    KAUST Repository

    Fortunato, Luca

    2016-10-07

    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. © 2016 Elsevier Ltd

  6. Influence of diatomite addition on membrane fouling and performance in a submerged membrane bioreactor.

    Science.gov (United States)

    Yang, Xiao-Li; Song, Hai-Liang; Lu, Ji-Lai; Fu, Da-Fang; Cheng, Bing

    2010-12-01

    This paper examined the effect of diatomite addition on membrane fouling and process performance in an anoxic/oxic submerged membrane bioreactor (A/O MBR). Particle size distribution, molecular weight distribution and microbial activity have been investigated to characterize the sludge mixed liquor. Results show that diatomite addition is a reliable and effective approach in terms of both membrane fouling mitigation and pollutants removal improvement. The MBR system with diatomite addition of 50 mg/L enhanced the removal of COD, TN and TP by 0.9%, 6.9% and 31.2%, respectively, as compared to the control MBR (without diatomite addition). The NH(4)-N removal always maintained at a high level of over 98% irrespective of diatomite addition. Due to the hybrid effect of adsorption and co-precipitation on fine colloids and dissolved organic matter (DOM) from the addition of diatomite, a reduction in foulants amount, an increase in microbial floc size and an improvement in sludge settleability have been achieved simultaneously. As a result, the membrane fouling rate was mitigated successfully. 2010 Elsevier Ltd. All rights reserved.

  7. Kinetic evaluation of nitrification performance in an immobilized cell membrane bioreactor.

    Science.gov (United States)

    Güven, D; Ubay Çokgör, E; Sözen, S; Orhon, D

    2016-01-01

    High rate membrane bioreactor (MBR) systems operated at extremely low sludge ages (superfast membrane bioreactors (SFMBRs)) are inefficient to achieve nitrogen removal, due to insufficient retention time for nitrifiers. Moreover, frequent chemical cleaning is required due to high biomass flux. This study aims to satisfy the nitrification in SFMBRs by using sponge as carriers, leading to the extension of the residence time of microorganisms. In order to test the limits of nitrification, bioreactor was run under 52, 5 and 2 days of carrier residence time (CRT), with a hydraulic retention time of 6 h. Different degrees of nitrification were obtained for different CRTs. Sponge immobilized SFMBR operation with short CRT resulted in partial nitrification indicating selective dominancy of ammonia oxidizers. At higher CRT, simultaneous nitrification-denitrification was achieved when accompanying with oxygen limitation. Process kinetics was determined through evaluation of the results by a modeling study. Nitrifier partition in the reactor was also identified by model calibration.

  8. Evaluation of a novel choanoid fluidized bed bioreactor for future bioartificial livers

    Science.gov (United States)

    Yu, Cheng-Bo; Pan, Xiao-Ping; Yu, Liang; Yu, Xiao-Peng; Du, Wei-Bo; Cao, Hong-Cui; Li, Jun; Chen, Ping; Li, Lan-Juan

    2014-01-01

    AIM: To construct and evaluate the functionality of a choanoid-fluidized bed bioreactor (CFBB) based on microencapsulated immortalized human hepatocytes. METHODS: Encapsulated hepatocytes were placed in the constructed CFBB and circulated through Dulbecco’s Modified Eagle’s Medium (DMEM) for 12 h, and then through exchanged plasma for 6 h, and compared with encapsulated cells cultivated under static conditions in a spinner flask. Levels of alanine aminotransferase (ALT) and albumin were used to evaluate the CFBB during media circulation, whereas levels of ALT, total bilirubin (TBil), and albumin were used to evaluate it during plasma circulation. Mass transfer and hepatocyte injury were evaluated by comparing the results from the two experimental conditions. In addition, the viability and microstructure of encapsulated cells were observed in the different environments. RESULTS: The bioartificial liver model based on a CFBB was verified by in vitro experiments. The viability of encapsulated cells accounting for 84.6% ± 3.7% in CFBB plasma perfusion was higher than the 74.8% ± 3.1% in the static culture group (P circulation and static medium culture groups, respectively. Albumin secretion from cells was 234.2 ± 27.8 μg/1 × 107 cells vs 167.8 ± 29.3 μg/1 × 107 cells at 6 h (P circulation/culture groups, respectively. Furthermore, ALT and TBil levels were 172.3 ± 24.1 U/L vs 236.3 ± 21.5 U/L (P 0.05) at 6 h in the CFBB plasma perfusion and static plasma culture groups, respectively. There was no significant difference in albumin concentration between the two experimental plasma groups at any time point. The microstructure of the encapsulated hepatocytes remained healthier in the CFBB group compared with the static culture group after 6 h of plasma perfusion. CONCLUSION: The CFBB can function as a bioartificial liver based on a bioreactor. The efficacy of this novel bioreactor is promising for the study of liver failure. PMID:24944477

  9. Fouling Issues in Membrane Bioreactors (MBRs for Wastewater Treatment: Major Mechanisms, Prevention and Control Strategies

    Directory of Open Access Journals (Sweden)

    Petros K. Gkotsis

    2014-10-01

    Full Text Available Membrane fouling is one of the most important considerations in the design and operation of membrane systems as it affects pretreatment needs, cleaning requirements, operating conditions, cost and performance. Given that membrane fouling represents the main limitation to membrane process operation, it is unsurprising that the majority of membrane material and process research and development conducted is dedicated to its characterization and amelioration. This work presents the fundamentals of fouling issues in membrane separations, with specific regard to membrane fouling in Membrane Bioreactors (MBRs and the most frequently applied preventive-control strategies. Feed pretreatment, physical and chemical cleaning protocols, optimal operation of MBR process and membrane surface modification are presented and discussed in detail. Membrane fouling is the major obstacle to the widespread application of the MBR technology and, therefore, fouling preventive-control strategies is a hot issue that strongly concerns not only the scientific community, but industry as well.

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

    Science.gov (United States)

    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).

  11. Pilot-scale testing membrane bioreactor for wastewater reclamation in industrial laundry

    DEFF Research Database (Denmark)

    Andersen, Martin; Kristensen, Gert Holm; Brynjolf, M.

    2002-01-01

    A pilot-scale study of membrane bioreactor treatment for reclamation of wastewater from Berendsen Textile Service industrial laundry in Søborg, Denmark was carried out over a 4 month period. A satisfactory COD degradation was performed resulting in a low COD in the permeate (

  12. Microbial population analysis of nutrient removal-related organisms in membrane bioreactors

    NARCIS (Netherlands)

    Silva, A.F.; Carvalho, G.; Oehmen, A.; Lousada-Ferreira, M.; Van Nieuwenhuijzen, A.; Reis, M.A.M.; Crespo, M.T.B.

    2012-01-01

    Membrane bioreactors (MBR) are an important and increasingly implemented wastewater treatment technology, which are operated at low food to microorganism ratios (F/M) and retain slow-growing organisms. Enhanced biological phosphorus removal (EBPR)-related organisms grow slower than ordinary

  13. Filtration Characterization Method as Tool to Assess Membrane Bioreactor Sludge Filterability—The Delft Experience

    NARCIS (Netherlands)

    Lousada-Ferreira, M.; Krzeminski, P.; Geilvoet, S.; Moreau, A.; Gil, J.A.; Evenblij, H.; Van Lier, J.B.; Van der Graaf, J.H.J.M.

    2014-01-01

    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

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

    Science.gov (United States)

    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.

  15. Characterization of the size-fractionated biomacromolecules: Tracking their role and fate in a membrane bioreactor

    DEFF Research Database (Denmark)

    Meng, Fangang; Zhou, Zhongbo; Ni, Bing-Jie

    2011-01-01

    and nuclear magnetic resonance (NMR) measurements were used to characterize BMM in a membrane bioreactor (MBR) from a chemical perspective. Overall, the BMM in sludge supernatant were mainly present in three fractions: colloidal BMM (BMMc, >0.45 μm), biopolymeric BMM (BMMb, 0.45 μm–100 kDa) and low molecular...

  16. Cake layer formation in anaerobic submerged membrane bioreactors (AnSMBR) for wastewater treatment

    NARCIS (Netherlands)

    Jeison, D.; Lier, van J.B.

    2006-01-01

    Cake layer formation in anaerobic gas-sparged submerged membrane bioreactors was studied using the critical flux concept, at 30 and 55 °C. The impact of biomass concentration, from 25 to 50 g TSS/L, and superficial gas velocity, up to 70 m/h, of over cake layer formation was studied, using response

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

    Science.gov (United States)

    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 ...

  18. Impact of suspended solids concentration on sludge filterability in Full-scale membrane bioreactors

    NARCIS (Netherlands)

    Lousada Ferreira, M.d.C.; Van Lier, J.B.; Van der Graaf, J.H.J.M.

    2015-01-01

    The relation between activated sludge filterability and mixed liquor suspended solids (MLSS) concentration in membrane bioreactors (MBRs) is framed in a single hypothesis, explaining results seemingly contradictory. A total of 44 activated sludge samples were collected and analyzed on a variety of

  19. Microbial population analysis of nutrient removal-related organisms in membrane bioreactors

    NARCIS (Netherlands)

    Silva, A.F.; Carvalho, G.; Oehmen, A.; Lousada-Ferreira, M.; Van Nieuwenhuijzen, A.; Reis, M.A.M.; Crespo, M.T.B.

    2012-01-01

    Membrane bioreactors (MBR) are an important and increasingly implemented wastewater treatment technology, which are operated at low food to microorganism ratios (F/M) and retain slow-growing organisms. Enhanced biological phosphorus removal (EBPR)-related organisms grow slower than ordinary heterotr

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

    KAUST Repository

    Malaeb, Lilian

    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/m2 (6.8 W/m3) with the biocathode, compared to 0.82 W/m2 (14.5 W/m3) 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. © 2013 American Chemical Society.

  1. Effect of pressure relaxation and membrane backwash on adenovirus removal in a membrane bioreactor.

    Science.gov (United States)

    Yin, Ziqiang; Tarabara, Volodymyr V; Xagoraraki, Irene

    2016-01-01

    Pressure relaxation and permeate backwash are two commonly used physical methods for membrane fouling mitigation in membrane bioreactor (MBR) systems. In order to assess the impact of these methods on virus removal by MBRs, experiments were conducted in a bench-scale submerged MBR treating synthetic wastewater. The membranes employed were hollow fibers with the nominal pore size of 0.45 μm. The experimental variables included durations of the filtration (tTMP>0), pressure relaxation (tTMP=0) and backwash (tTMP0/tTMP=0, longer filtration/relaxation cycles (i.e. larger tTMP+tTMP=0) led to higher transmembrane pressure (TMP) but did not have a significant impact on HAdV removal. A shorter backwash (tTMP<0 = 10 min) at a higher flow rate (Q = 40 mL/min) resulted in more substantial decreases in TMP and HAdV removal than a longer backwash (tTMP<0 = 20 min) at a lower flow rate (Q = 20 mL/min) even though the backwash volume (QtTMP<0) was the same. HAdV removal returned to pre-cleaning levels within 16 h after backwash was applied. Moderate to strong correlations (R(2) = 0.63 to 0.94) were found between TMP and HAdV removal.

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

    Science.gov (United States)

    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.

  3. Effect of sludge retention time on sludge characteristics and membrane fouling of membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    OUYANG Ke; LIU Junxin

    2009-01-01

    Three identical membrane bioreactors (MBRs) were operated over 2 years at different sludge retention times (SRT) of 10, 40 d and no sludge withdrawal (NS), respectively, to elucidate and quantify the effect of SRT on the sludge characteristics and membrane fouling. The hydraulic retention times of these MBRs were controlled at 12 h. With increasing SRT, the sludge concentrations in the MBRs increased, whereas the ratio of volatile suspended solid to the total solid decreased, and the size of sludge granule diminished in the meantime. A higher sludge concentration at long SRT could maintain a better organic removal efficiency, and a longer SRT was propitious to the growth of nitrifiers. The performance of these MBRs for the removal of COD and NH4+-N did not change much with different SRTs. However, the bioactivity decreased as SRT increased. The measurements of specific oxygen uptake rates (SOUR) and fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes testified that SOUR and the proportion of the bacteria-specific probe EUB338 in all DAPI-stainable bacteria decreased with increasing SRT. The concentrations of total organic carbon, protein, polysaccharides and soluble extracellular polymeric substance (EPS) in the mixed liquor supernatant decreased too with increasing SRT. The membrane fouling rate was higher at shorter SRT, and the highest fouling rate appeared at a SRT of 10 d. Both the sludge cake layer and gel layer had contribution to the fouling resistance, but the relative contribution of the gel layer decreased as SRT increased.

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

    Science.gov (United States)

    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).

  5. The potential of hybrid forward osmosis membrane bioreactor (FOMBR) processes in achieving high throughput treatment of municipal wastewater with enhanced phosphorus recovery.

    Science.gov (United States)

    Qiu, Guanglei; Zhang, Sui; Srinivasa Raghavan, Divya Shankari; Das, Subhabrata; Ting, Yen-Peng

    2016-11-15

    Extensive research in recent years has explored numerous new features in the forward osmosis membrane bioreactor (FOMBR) process. However, there is an aspect, which is revolutionary but not yet been investigated. In FOMBR, FO membrane shows high rejection for a wide range of soluble contaminants. As a result, hydraulic retention time (HRT) does not correctly reflect the nominal retention of these dissolved contaminants in the bioreactor. This decoupling of contaminants retention time (CRT, i.e. the nominal retention of the dissolved contaminants) from HRT endows FOMBR a potential in significantly reducing the HRT for wastewater treatment. In this work, we report our results in this unexplored treatment potential. Using real municipal wastewater as feed, both a hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) and a newly developed hybrid biofilm-forward osmosis membrane bioreactor (BF-FOMBR) achieved high removal of organic matter and nitrogen under HRT of down to 2.0 h, with significantly enhanced phosphorus recovery capacities. In the BF-FOMBR, the used of fixed bed biofilm not only obviated the need of additional solid/liquid separation (e.g. MF) to extract the side-stream for salt accumulation control and phosphorus recovery, but effectively quarantined the biomass from the FO membrane. The absence of MF in the side-stream further allowed suspended growth to be continuously removed from the system, which produced a selection pressure for the predominance of attached growth. As a result, a significant reduction in FO membrane fouling (by 24.7-54.5%) was achieved in the BF-FOMBR due to substantially reduced bacteria deposition and colonization.

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

    Science.gov (United States)

    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.

  7. Lipase production by solid-state fermentation: cultivation conditions and operation of tray and packed-bed bioreactors.

    Science.gov (United States)

    Gutarra, Melissa L E; Cavalcanti, Elisa D C; Castilho, Leda R; Freire, Denise M G; Sant'Anna, Geraldo L

    2005-01-01

    The production of lipase by Penicillium simplicissimum in solid-state fermentation was studied using babassu cake as the basal medium. Tray-type and packed-bed bioreactors were employed. In the former, the influence of temperature; content of the medium, and medium supplementation with olive oil, sugarcane molasses, corn steep liquor, and yeast hydrolysate was studied. For all combinations of supplements, a temperature of 30 degrees C, a moisture content of 70%, and a concentration of carbon source of 6.25% (m/m, dry basis) provided optimum conditions for lipase production. When used as single supplements olive oil and molasses also were able to provide high lipase activities (20 U/g). Using packed-bed bioreactors and molasses-supplemented medium, optimum conditions for enzyme production were air superficial velocities above 55 cm/min and temperatures below 28 degrees C. The lower temperature optimum found for these reactors is probably related to radial heat gradient formation inside the packed bed. Maximum lipase activities obtained in these bioreactors (26.4 U/g) were 30% higher than in tray-type reactors.

  8. Removal of trace organic contaminants by a membrane bioreactor-granular activated carbon (MBR-GAC) system.

    Science.gov (United States)

    Nguyen, Luong N; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D

    2012-06-01

    The removal of trace organics by a membrane bioreactor-granular activated carbon (MBR-GAC) integrated system were investigated. The results confirmed that MBR treatment can be effective for the removal of hydrophobic (log D>3.2) and readily biodegradable trace organics. The data also highlighted the limitation of MBR in removing hydrophilic and persistent compounds (e.g. carbamazepine, diclofenac, and fenoprop) and that GAC could complement MBR very well as a post-treatment process. The MBR-GAC system showed high removal of all selected trace organics including those that are hydrophilic and persistent to biological degradation at up to 406 bed volumes (BV). However, over an extended period, breakthrough of diclofenac was observed after 7320 BV. This suggests that strict monitoring should be applied over the lifetime of the GAC column to detect the breakthrough of hydrophilic and persistent compounds which have low removal by MBR treatment.

  9. Biodegradation of benzene, toluene, ethylbenzene, and o-xylene by a coculture of Pseudomonas putida and Pseudomonas fluorescens immobilized in a fibrous-bed bioreactor.

    Science.gov (United States)

    Shim, H; Yang, S T

    1999-01-22

    A fibrous-bed bioreactor containing the coculture of Pseudomonas putida and P. fluorescens immobilized in a fibrous matrix was developed to degrade benzene (B), toluene (T), ethylbenzene (E), and o-xylene (X) in synthetic waste streams. The kinetics of BTEX biodegradation by immobilized cells adapted in the fibrous-bed bioreactor and free cells grown in serum bottles were studied. In general, the BTEX biodegradation rate increased with increasing substrate concentration and then decreased after reaching a maximum, showing substrate-inhibition kinetics. However, for immobilized cells, the degradation rate was much higher than that of free cells. Compared to free cells, immobilized cells in the bioreactor tolerated higher concentrations (> 1000 mg l-1) of benzene and toluene, and gave at least 16-fold higher degradation rates for benzene, ethylbenzene, and o-xylene, and a 9-fold higher degradation rate for toluene. Complete and simultaneous degradation of BTEX mixture was achieved in the bioreactor under hypoxic conditions. Cells in the bioreactor were relatively insensitive to benzene toxicity; this insensitivity was attributed to adaptation of the cells in the bioreactor. Compared to the original seeding culture, the adapted cells from the fibrous-bed bioreactor had higher specific growth rate, benzene degradation rate, and cell yield when the benzene concentration was higher than 100 mg l-1. Cells in the fibrous bed had a long, slim morphology, which is different from the normal short-rod shape found for suspended cells in solution.

  10. EXPERIMENTAL STUDY ON THE GAS-LIQUID FLOW IN THE MEMBRANE MICROPORE AERATION BIOREACTOR

    Directory of Open Access Journals (Sweden)

    DONG LIU

    2008-12-01

    Full Text Available Particle Image Velocimetry (PIV has been developed to measure the typical two-phase flow of various work conditions in Membrane Micropore Aeration Bioreactor (MMAB. The fluid phase is separated out using image processing techniques, which provides accurate measurements for the Bioreactor’s flow field, and makes it possible for quantitative analysis of the momentum exchange, heat exchange and the process of micro-admixture. The experimental method PIV used in this paper can preferably measure the complex flow in the reactor and initiates a new approach for the bioreactor design which mainly depends on experience at present.

  11. Preparation of [11C]formaldehyde using a hollow fiber membrane bioreactor.

    Science.gov (United States)

    Hughes, J A; Jay, M

    1995-01-01

    A bioreactor consisting of the enzymes alcohol oxidase and catalase immobilized onto a hollow fiber membrane was used to convert [11C]methanol to [11C]formaldehyde. Using an alcohol oxidase:catalase ratio of 1:500 U, conversion yields of 90-95% were obtained allowing the production of up to 7400 MBq (200 mCi) of [11C]formaldehyde in 5 min. The hollow fiber bioreactor allowed for a convenient, rapid synthesis with yields significantly higher than the standard chemical procedures, has demonstrable advantages over glass bead immobilized systems (primarily due to convective flow), and was amenable to hot cell conditions.

  12. Combination of electrochemical processes with membrane bioreactors for wastewater treatment and fouling control: A review

    Directory of Open Access Journals (Sweden)

    Benny Marie B. Ensano

    2016-08-01

    Full Text Available This paper provides a critical review about the integration of electrochemical processes into membrane bioreactors (MBR in order to understand the influence of these processes on wastewater treatment performance and membrane fouling control. The integration can be realized either in an internal or an external configuration. Electrically enhanced membrane bioreactors or electro membrane bioreactors (eMBRs combine biodegradation, electrochemical and membrane filtration processes into one system providing higher effluent quality as compared to conventional MBRs and activated sludge plants. Furthermore, electrochemical processes, such as electrocoagulation, electrophoresis and electroosmosis, help to mitigate deposition of foulants into the membrane and enhance sludge dewaterability by controlling the morphological properties and mobility of the colloidal particles and bulk liquid. Intermittent application of minute electric field has proven to reduce energy consumption and operational cost as well as minimize the negative effect of direct current field on microbial activity which are some of the main concerns in eMBR technology. The present review discusses important design considerations of eMBR, its advantages as well as its applications to different types of wastewater. It also presents several challenges that need to be addressed for future development of this hybrid technology which include treatment of high strength industrial wastewater and removal of emerging contaminants, optimization study, cost benefit analysis and the possible combination with microbial electrolysis cell for biohydrogen production.

  13. Selective adhesion of wastewater bacteria to Pleurotus ostreatus mycelium in a trickle-bed bioreactor

    Directory of Open Access Journals (Sweden)

    Čeněk Novotný

    2016-07-01

    Full Text Available The work is focused on spontaneous colonization of fungal mycelium by invading microorganisms in a trickle-bed fungal bioreactor operating under semi-sterile conditions. Pleurotus ostreatus was grown under the flow of synthetic wastewater containing activated sludge bacteria and the microbial consortium developed in the reactor was characterized. Genotype and phenotype profile of the reactor-invading, bacterial consortium was clearly distinctive from that of the original activated sludge. The bacterial consortium from the reactor contained a higher portion of bacteria capable of cellobiose utilization and a small amount of bacteria with the ability to utilize benzoic acids. The invading bacteria had no effect on the dye decolorization performance of the fungal reactor. Five bacterial strains colonizing P. ostreatus reactor cultures were isolated and identified as species of the genera Pseudomonas and Bacillus. Except for Bacillus cereus all strains displayed a potential to inhibit fungal growth on solid media (14 to 51 % inhibition which was comparable or higher than that of the reference bacterial strains. The pH- and media composition-dependence of the growth inhibition was demonstrated.

  14. Butyric acid fermentation in a fibrous bed bioreactor with immobilized Clostridium tyrobutyricum from cane molasses.

    Science.gov (United States)

    Jiang, Ling; Wang, Jufang; Liang, Shizhong; Wang, Xiaoning; Cen, Peilin; Xu, Zhinan

    2009-07-01

    Butyrate fermentation by immobilized Clostridium tyrobutyricum was successfully carried out in a fibrous bed bioreactor using cane molasses. Batch fermentations were conducted to investigate the influence of pH on the metabolism of the strain, and the results showed that the fermentation gave a highest butyrate production of 26.2 g l(-1) with yield of 0.47 g g(-1) and reactor productivity up to 4.13 g l(-1)h(-1) at pH 6.0. When repeated-batch fermentation was carried out, long-term operation with high butyrate yield, volumetric productivity was achieved. Several cane molasses pretreatment techniques were investigated, and it was found that sulfuric acid treatment gave better results regarding butyrate concentration (34.6+/-0.8 g l(-1)), yield (0.58+/-0.01 g g(-1)), and sugar utilization (90.8+/-0.9%). Also, fed-batch fermentation from cane molasses pretreated with sulfuric acid was performed to further increase the concentration of butyrate up to 55.2 g l(-1).

  15. Phenol degradation in a three-phase fluidized-bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Richards, A.D.; Fricke, A.M.; Scott, J.E.

    1983-06-01

    The operation of a three-phase fluidized-bed bioreactor for removing phenol from wastewater was studied. The reactor system consisted of a bacterial population (predominantly pseudomonads) attached to inert coal particles, which was fluidized by a stream of simulated wastewater containing approximately 0.1 g/L phenol. Oxygen was bubbled through the reactor to support the aerobic bacteria. The kinetics of phenol degradation by the attached organisms was investigated in batch shake-flask experiments. The rate of phenol degradation showed a first-order dependence on phenol concentration at high-oxygen concentrations (P/sub O/sub 2// = 1 atm) and a zero-order dependence on phenol at low-oxygen concentrations (P/sub O/sub 2// less than or equal to 0.2 atm). The kinetic data were well-described by a competitive inhibition model. The reactor was modeled as well-mixed with gas-liquid interfacial mass-transfer limitations. The model predicted an optimal value for the mass-transfer coefficient, above which oxygen inhibition reduces performance and below which mass-transfer limitations occur. Comparison of reactor operating data with model predictions showed that the liquid phase of the reactor was well-mixed and that the reaction rate was limited by the mass transfer of oxygen from the gaseous to the liquid phase. The mass-transfer component should be increased for more efficient reactor operation.

  16. Performance of fluidized bed bioreactor containing wire-mesh sponge particles in wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kargi, F.; Karapinar, I. [Dokuz Eyluel Univ., Izmir (Turkey). Dept. of Environmental Engineering

    1997-12-31

    Synthetic wastewater treatment performance of a continuous-flow, fluidized bed bioreactor was investigated at different particle number densities. Porous-sponge particles surrounded by steel wires were used as support material. COD removal rate and efficiency increased from r = 1,150 mg l{sup {minus}1} h{sup {minus}1} and E = 68% to r = 1,400 mg l{sup {minus}1} h{sup {minus}1} and E = 96% when particle number density (PND) increased from PND = 551{sup {minus}1} to PND = 4,401l{sup {minus}1} at a constant hydraulic residence time (HRT) of 9 h. The system`s performance was also evaluated at different hydraulic residence times ({Theta}{sub H} = 3--9 h) with a high particle number density of PND = 6,701{sup {minus}1}. Synthetic wastewater used throughout the studies consisted of diluted molasses, urea, K{sub 2}HPO{sub 4} and MgSO{sub 4} resulting in a ratio of COD/N/P = 100/10/1. Zooglea ramigera was the dominant microorganism in the FBBR. Apparent Monod kinetic constants of the system were determined as r{sub m} = 1,250 mg l{sup {minus}1} h{sup {minus}1} and K{sub s} = 1,150 mg l{sup {minus}1} by using the experimental data for PND = 6,701{sup {minus}1}.

  17. Ethanol production from dry-mill corn starch in a fluidized-bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, M.S.; Nghiem, N.P.; Davison, B.H.

    1998-08-01

    The development of a high-rate process for the production of fuel ethanol from dry-mill corn starch using fluidized-bed bioreactor (FBR) technology is discussed. Experiments were conducted in a laboratory scale FBR using immobilized biocatalysts. Two ethanol production process designs were considered in this study. In the first design, simultaneous saccharification and fermentation was performed at 35 C using {kappa}-carageenan beads (1.5 mm to 1.5 mm in diameter) of co-immobilized glucoamylase and Zymomonas mobilis. For dextrin feed concentration of 100 g/L, the single-pass conversion ranged from 54% to 89%. Ethanol concentrations of 23 to 36 g/L were obtained at volumetric productivities of 9 to 15 g/L-h. No accumulation of glucose was observed, indicating that saccharification was the rate-limiting step. In the second design, saccharification and fermentation were carried out sequentially. In the first stage, solutions of 150 to 160 g/L dextrins were pumped through an immobilized glucoamylase packed column maintained at 55 C. Greater than 95% conversion was obtained at a residence time of 1 h, giving a product of 165 to 170 g glucose/L. In the second stage, these glucose solutions were fed to the FBR containing Z. mobilis immobilized in {kappa}-carageenan beads. At a residence time of 2 h, 94% conversion and ethanol concentration of 70 g/L was achieved, giving an overall productivity of 23 g/L-h.

  18. Fructose Production by Inulinase Covalently Immobilized on Sepabeads in Batch and Fluidized Bed Bioreactor

    Directory of Open Access Journals (Sweden)

    Gabriele Iorio

    2010-03-01

    Full Text Available The present work is an experimental study of the performance of a recently designed immobilized enzyme: inulinase from Aspergillus sp. covalently immobilized on Sepabeads. The aim of the work is to test the new biocatalyst in conditions of industrial interest and to assess the feasibility of the process in a fluidized bed bioreactor (FBBR. The catalyst was first tested in a batch reactor at standard conditions and in various sets of conditions of interest for the process. Once the response of the catalyst to different operating conditions was tested and the operational stability assessed, one of the sets of conditions tested in batch was chosen for tests in FBBR. Prior to reaction tests, preliminary fluidization tests were realized in order to define an operating range of admissible flow rates. As a result, the FBR was run at different feed flow rates in a closed cycle configuration and its performance was compared to that of the batch system. The FBBR proved to be performing and suitable for scale up to large fructose production.

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

    Science.gov (United States)

    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.

  20. Production of human alpha-1-antitrypsin from transgenic rice cell culture in a membrane bioreactor.

    Science.gov (United States)

    McDonald, Karen A; Hong, Lo Ming; Trombly, David M; Xie, Qing; Jackman, Alan P

    2005-01-01

    Transgenic plant cell cultures offer a number of advantages over alternative host expression systems, but so far relatively low product concentrations have been achieved. In this study, transgenic rice cells are used in a two-compartment membrane bioreactor (CELLine 350, Integra Biosciences) for the production of recombinant alpha-1-antitrypsin (rAAT). Expression of rAAT is controlled by the rice alpha-amylase (RAmy3D) promoter, which is induced in the absence of sugar. The extracellular product is retained in the bioreactor's relatively small cell compartment, thereby increasing product concentration. Due to the packed nature of the cell aggregates in the cell compartment, a clarified product solution can be withdrawn from the bioreactor. Active rAAT reached levels of 100-247 mg/L (4-10% of the total extracellular protein) in the cell compartment at 5-6 days postinduction, and multiple inductions of the RAmy3D promoter were demonstrated.

  1. Enhanced poly(γ-glutamic acid) fermentation by Bacillus subtilis NX-2 immobilized in an aerobic plant fibrous-bed bioreactor.

    Science.gov (United States)

    Xu, Zongqi; Feng, Xiaohai; Zhang, Dan; Tang, Bao; Lei, Peng; Liang, Jinfeng; Xu, Hong

    2014-03-01

    To enhance poly(γ-glutamic acid) (PGA) production, a novel aerobic plant fibrous-bed bioreactor (APFB) was constructed for immobilized fermentation. Based on the analysis of the kinetics of immobilized-cell fermentation using the APFB and conventional free-cell fermentation, immobilized-cell fermentation exhibited more efficient PGA production. Furthermore, repeated fed-batch cultures for PGA production were conducted to evaluate the stability of the APFB system. Average final PGA concentration and productivity of 71.21±0.83g/L and 1.246±0.008g/L/h were respectively achieved by cells immobilized in bagasse during APFB, which was reused eight times over a period of 457±18h. Analysis of the membrane phospholipids and the key enzyme activities indicated that APFB-adapted cells had better productivity than original cells. Thus, this study demonstrated the significant potential of the APFB culture system in future industrial applications.

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

    Science.gov (United States)

    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. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  4. Production of surfactin and fengycin by Bacillus subtilis in a bubbleless membrane bioreactor.

    Science.gov (United States)

    Coutte, François; Lecouturier, Didier; Yahia, Saliha Ait; Leclère, Valérie; Béchet, Max; Jacques, Philippe; Dhulster, Pascal

    2010-06-01

    Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air-liquid contactor to prevent foam formation. Three different configurations were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume was in the same range: 242, 230, and 188 mg l(-1) for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l(-1) for BB1, 207 mg l(-1) for BB2, and 393 mg l(-1) for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with the submerged polypropylene membrane.

  5. Investigation of a dual-particle liquid-solid circulating fluidized bed bioreactor for extractive fermentation of lactic acid.

    Science.gov (United States)

    Patel, Manoj; Bassi, Amarjeet S; Zhu, Jesse J-X; Gomaa, Hassan

    2008-01-01

    A dual-particle liquid-solid circulating fluidized bed (DP-LSCFB) bioreactor has been constructed and investigated for the simultaneous production and extraction of lactic acid using immobilized Lactobacillus bulgaricus and ion-exchange resins. The apparatus consisted of a downer fluidized bed, 13 cm I.D. and 4.75 m tall, and a riser fluidized bed, 3.8 cm I.D. and 5.15 m in height. The lactic acid production and removal was carried out in the downer, while the riser was used for the recovery of lactic acid. A continuously recirculating bed of ion-exchange resin was used for adsorption of the produced acid as well as for maintaining optimum pH for bioconversion, thus eliminating the need for costly and complex chemical control approach used in conventional techniques. Studies using lactic acid aqueous solution as feed and sodium hydroxide solution as regeneration stream showed 93% lactic acid removal from the downer and 46% recovery in the riser under the conditions investigated. Such results prove the functionality of using the newly developed bioreactor design for the continuous production and recovery of products of biotechnological significance.

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

    Science.gov (United States)

    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.

  7. Inorganic fouling of an anaerobic membrane bioreactor treating leachate from the organic fraction of municipal solid waste (OFMSW) and a polishing aerobic membrane bioreactor.

    Science.gov (United States)

    Trzcinski, Antoine P; Stuckey, David C

    2016-03-01

    The treatment of leachate (Average TCOD=11.97 g/L, 14.4% soluble) from the organic fraction of municipal solid waste was investigated using a Submerged Anaerobic Membrane BioReactor (SAMBR), followed by an aerobic membrane bioreactor (AMBR) to polish this effluent. This paper investigated the exact nature and composition of the inorganic precipitate in each of the reactors in the process. The flux decreased due to precipitation of calcium as monohydrocalcite (CaCO3·H2O) containing traces of metals onto the SAMBR membrane because of high CO2 partial pressures. Precipitation of calcium in the AMBR was also observed due to a higher pH. In this case, phosphorus also precipitated with calcium in two different phases: the background layer contained calcium, oxygen, carbon and small amounts of phosphorus (2-6.7%), while flakes containing calcium, oxygen and higher amounts of phosphorus (10-17%) were probably hydroxyapatite (Ca5(PO4)3OH). Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  9. Biodegradation of toluene using Candida tropicalis immobilized on polymer matrices in fluidized bed bioreactors.

    Science.gov (United States)

    Song, JiHyeon; Namgung, HyeongKyu; Ahmed, Zubair

    2012-11-30

    A yeast strain, Candida tropicalis, was whole-cell-immobilized on polymer matrices of polyethylene glycol (PEG) and polyethylene glycol/activated carbon/alginate (PACA). The polymer matrices were used as fluidized materials in bubble-column bioreactors for the biodegradation of toluene. Simultaneously, another bubble-column bioreactor using granular activated carbon (GAC) and a conventional compost biofilter were operated for comparison. In the compost biofilter, the toluene removal efficiency gradually deteriorated due to the limitation of microbial activity. The toluene removal in the GAC bioreactor was relatively high because of an increase of toluene mass transfer. However, low toluene removal efficiencies were observed in the PEG bioreactor, presumably because the synthetic polymer alone was not suitable for yeast cell immobilization. In the PACA bioreactor, toluene removal was found to be greater than 95% overall. The CO(2) yield coefficient calculated at the highest toluene loading condition for the PACA bioreactor was found to be higher than those observed in the other bioreactors. Furthermore, almost complete elimination capacities were observed in the PACA bioreactor at short-term toluene loading up to 180 g/m(3)/h. In conclusion, the immobilization of C. tropicalis in the PACA matrix resulted in enhanced toluene biodegradation because of the increases of both mass transfer and microbial activity.

  10. Comparison of the Modeling Approach between Membrane Bioreactor and Conventional Activated Sludge Processes

    DEFF Research Database (Denmark)

    Jiang, Tao; Sin, Gürkan; Spanjers, Henri

    2009-01-01

    Activated sludge models (ASM) have been developed and largely applied in conventional activated sludge (CAS) systems. The applicability of ASM to model membrane bioreactors (MBR) and the differences in modeling approaches have not been studied in detail. A laboratory-scale MBR was modeled using ASM...... to the inhibition effect of soluble microbial products (SMP) at elevated concentration. Second, a greater biomass affinity to oxygen and ammonium was found, which was probably related to smaller MBR sludge flocs. Finally, the membrane throughput during membrane backwashing/relaxation can be normalized...

  11. Continuous acetic acid production by a packed bed bioreactor employing charcoal pellets derived from waste mushroom medium.

    Science.gov (United States)

    Horiuchi, J; Tabata, K; Kanno, T; Kobayashi, M

    2000-01-01

    A packed bed bioreactor using charcoal pellets produced from waste mushroom medium by thermal carbonization was developed and applied to continuous acetic acid production. The pellets were characterized by their high specific surface area (200 m2/g) with numerous micropores (2-10 microm). The continuous acetic acid fermentation started up smoothly after seeding and was successfully operated for about 180 d under various retention times. The maximum acetic acid productivity was about 3.9 g/l/h using normal aeration and 6.5 g/l/h using air enriched with 40% O2. The pellets are expected to prove useful as a new packing material for bioreactor in terms of their bacterial affinity, high specific surface area with appropriate pore sizes for bacteria, as well as the operational stability of the system and the low production cost.

  12. Lipase production by solid-state fermentation in fixed-bed bioreactors

    Directory of Open Access Journals (Sweden)

    Elisa d'Avila Costa Cavalcanti

    2005-06-01

    Full Text Available In the present work, packed bed bioreactors were employed with the aim of increasing productivity and scaling up of lipase production using Penicillium simplicissimum in solid-state fermentation. The influence of temperature and air flow rate on enzyme production was evaluated employing statistical experimental design, and an empirical model was adjusted to the experimental data. It was shown that higher lipase activities could be achieved at lower temperatures and higher air flow rates. The maximum lipase activity (26.4 U/g was obtained at the temperature of 27°C and air flow rate of 0.8 L/min.O fungo Penicillium simplicissimum se mostrou, em trabalhos anteriores, um ótimo produtor de lipase por fermentação no estado sólido, quando cultivado em biorreatores do tipo bandeja, utilizando a torta de babaçu como meio de cultura. Com o objetivo de aumentar a produtividade e possibilitar uma ampliação de escala, foi investigado, no presente trabalho, o emprego de biorreatores de leito fixo com aeração forçada. Os biorreatores utilizados tinham 4 cm de diâmetro interno e 14 cm de altura útil. Empregando-se planejamento estatístico de experimentos como ferramenta, foram avaliadas as influências da temperatura e da vazão de ar sobre a produção de lipase nestes biorreatores. Os resultados obtidos permitiram ajustar um modelo empírico, o qual indicou que maiores atividades lipásicas são alcançadas para temperaturas mais baixas e vazões de ar mais altas. A atividade lipásica máxima (26,4 U/g foi obtida para temperatura de 27°C e vazão de ar de 0,8 L/min.

  13. Fluidized-Bed Bioreactor Applications for Biological Wastewater Treatment: A Review of Research and Developments

    Directory of Open Access Journals (Sweden)

    Michael J. Nelson

    2017-06-01

    Full Text Available Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the activated sludge process, despite their long operating times. However, population increases have created a demand for more efficient means of wastewater treatment. Fluidization has been demonstrated to increase the efficiency of many processes in chemical and biochemical engineering, but it has not been widely used in large-scale wastewater treatment. At the University of Western Ontario, the circulating fluidized-bed bioreactor (CFBBR was developed for treating wastewater. In this process, carrier particles develop a biofilm composed of bacteria and other microbes. The excellent mixing and mass transfer characteristics inherent to fluidization make this process very effective at treating both municipal and industrial wastewater. Studies of lab- and pilot-scale systems showed that the CFBBR can remove over 90% of the influent organic matter and 80% of the nitrogen, and produces less than one-third as much biological sludge as the activated sludge process. Due to its high efficiency, the CFBBR can also be used to treat wastewaters with high organic solid concentrations, which are more difficult to treat with conventional methods because they require longer residence times; the CFBBR can also be used to reduce the system size and footprint. In addition, it is much better at handling and recovering from dynamic loadings (i.e., varying influent volume and concentrations than current systems. Overall, the CFBBR has been shown to be a very effective means of treating wastewater, and to be capable of treating larger volumes of wastewater using a smaller reactor volume and a shorter residence time. In addition, its compact design holds potential for more geographically localized and isolated wastewater treatment systems.

  14. Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jong, T.; Parry, D.L. [Charles Darwin University, Darwin, NT (Australia). Faculty for Educational Health & Science

    2006-07-15

    The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values of 6.0, 5.0, 4.5, 4.0 and 3.5 in a synthetic medium containing 53.5 mmol l{sup -1} lactate. Sulfate reduction rates of 553-1052 mmol m{sup -3} d{sup -1} were obtained when the influent solution pH was progressively lowered from pH 6.0 to 4.0, under an optimal flow rate of 2.61 ml min{sup -1}. When the influent pH was further lowered to pH 3.5, sulfate reduction was substantially reduced with only about 1% sulfate removed at a rate of 3.35 mmol m{sup -3} d{sup -1} after 20 days of operation. However, viable SRB were recovered from the column, indicating that the SRB population was capable of surviving and metabolizing at low levels even at pH 3.5 conditions for at least 20 days. The changes in conductivity in the SRB column did not always occur with changes in pH and redox potential, suggesting that conductivity measurements may be more sensitive to SRB activity and could be used as an additional tool for monitoring SRB activity. The bioreactor containing SRB was able to reduce sulfate and generate alkalinity even when challenged with influent as low as pH 3.5, indicating that such treatment systems have potential for bioremediating highly acidic, sulfate contaminated waste waters.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Evolution and accumulation of organic foulants on hydrophobic and hydrophilic membrane surfaces in a submerged membrane bioreactor

    KAUST Repository

    Matar, Gerald

    2015-09-07

    Membrane surface modification is attracting more attention to mitigate biofouling in membrane bioreactors (MBRs). Five membranes differing in chemistry and hydrophobic/hydrophilic potential were run in parallel in a lab-scale MBR under the same conditions. Membranes were sampled after 1, 10, 20 and 30 days of MBR operation with synthetic wastewater. Subsequently, accumulated organic foulants were characterised using several chemical analytical tools. Results showed similar development of organic foulants with time, illustrating that membrane surface chemistry did not affect the selection of specific organic foulants. Multivariate analysis showed that biofilm samples clustered according to the day of sampling. The composition of organic foulants shifted from protein-like substances towards humics and polysaccharides-like substances. We propose that to control biofouling in MBRs, one should focus less on the membrane surface chemistry.

  18. Modeling of submerged membrane bioreactor treating cheese whey wastewater by artificial neural network.

    Science.gov (United States)

    Cinar, Ozer; Hasar, Halil; Kinaci, Cumali

    2006-05-17

    A submerged membrane bioreactor receiving cheese whey was modeled by artificial neural network and its performance over a period of 100 days at different solids retention times was evaluated with this robust tool. A cascade-forward network was used to model the membrane bioreactor and normalization was used as a preprocessing method. The network was fed with two subsets of operational data, with two-thirds being used for training and one-third for testing the performance of the artificial neural network. The training procedure for effluent chemical oxygen demand (COD), ammonia, nitrate and total phosphate concentrations was very successful and a perfect match was obtained between the measured and the calculated concentrations. The results of the confirmation (or testing) procedure for effluent ammonia and nitrate concentrations were very successful; however, the results of the confirmation procedure for effluent COD and total phosphate concentrations were only satisfactory.

  19. The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors

    DEFF Research Database (Denmark)

    Tirunehe, Gossay; Norddahl, B.

    2016-01-01

    Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air–water and air–CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas–liquid mediums. CMC...... solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas–liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (UG) range of 0.0004–0.0025 m....../s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular...

  20. Pilot-scale testing membrane bioreactor for wastewater reclamation in industrial laundry

    DEFF Research Database (Denmark)

    Andersen, Martin; Kristensen, Gert Holm; Brynjolf, M.;

    2002-01-01

    A pilot-scale study of membrane bioreactor treatment for reclamation of wastewater from Berendsen Textile Service industrial laundry in Søborg, Denmark was carried out over a 4 month period. A satisfactory COD degradation was performed resulting in a low COD in the permeate (< 50 mg/l). To obtain...... of water to the wash processes. Reuse of the permeate in all rinsing steps requires additional treatment through reverse osmosis....

  1. Filtration characterization method as tool to assess membrane bioreactor sludge filterability-the Delft experience

    OpenAIRE

    Maria Lousada-Ferreira; Pawel Krzeminski; Stefan Geilvoet; Adrien Moreau; Jose A. Gil; Herman Evenblij; van Lier, Jules B.; van der Graaf, Jaap H.J.M.

    2014-01-01

    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 an...

  2. A Novel Electrochemical Membrane Bioreactor as a Potential Net Energy Producer for Sustainable Wastewater Treatment

    OpenAIRE

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

    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 ene...

  3. Pilot-scale testing membrane bioreactor for wastewater reclamation in industrial laundry.

    Science.gov (United States)

    Andersen, M; Kristensen, G H; Brynjolf, M; Grüttner, H

    2002-01-01

    A pilot-scale study of membrane bioreactor treatment for reclamation of wastewater from Berendsen Textile Service industrial laundry in Søborg, Denmark was carried out over a 4 month period. A satisfactory COD degradation was performed resulting in a low COD in the permeate (treatment, addition of nitrogen was necessary. The biodegradability of the permeate was very low (BOD5 treatment through reverse osmosis.

  4. COUPLING OF MEMBRANE BIOREACTOR AND OZONATION FOR REMOVAL OF ANTIBIOTICS FROM HOSPITAL WASTEWATER

    OpenAIRE

    Bui Xuan Thanh; Quyen Vo Thi Kim; Phuc Luu Vinh; Tin Nguyen Thanh; Hien Vo Thi Dieu; Thanh Cao Ngoc Dan; Quoc Tuc Dinh,

    2016-01-01

    Antibiotic residues in the environment and their potential toxic effects have been considered as one of the emerging research area in the environmental field. Their continuous introduction in our environment may increase their negative impacts on human health.  In this study, the eliminations of antibiotic such as Norfloxacin (NOR), Ciprofloxacin (CIP), Ofloxacin (OFL) and Sulfamethoxazole (SMZ) in wastewater of hospital were processed by membrane bioreactor (MBR) coupled with ozonation proce...

  5. Nutrient removal from an anaerobic membrane bioreactor effluent using microalgae. Study and modeling of the process.

    OpenAIRE

    Ruiz Martínez, Ana

    2016-01-01

    [EN] Anaerobic membrane bioreactors for urban wastewater treatment present interesting advantages when compared with aerobic treatments, such as less sludge production, lower energy demand and biogas generation. However, the generated effluent cannot generally be discharged without further ammonium and phosphate elimination. This thesis studies the removal of these inorganic nutrients by means of microalgae cultivation. The main objective of this work is therefore to obtain an autochthono...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Kayleigh; Ghoshdastidar, Avik J.; Hanmore, Jillian [Department of Chemistry, Acadia University, Wolfville, NS, Canada B4P 2R6 (Canada); Frazee, James [E and Q Consulting and Associates Limited, Wolfville, NS, Canada B4P 2R1 (Canada); Tong, Anthony Z., E-mail: anthony.tong@acadiau.ca [Department of Chemistry, Acadia University, Wolfville, NS, Canada B4P 2R6 (Canada)

    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.

  8. Application of enhanced membrane bioreactor (eMBR) to treat dye wastewater.

    Science.gov (United States)

    Rondon, Hector; El-Cheikh, William; Boluarte, Ida Alicia Rodriguez; Chang, Chia-Yuan; Bagshaw, Steve; Farago, Leanne; Jegatheesan, Veeriah; Shu, Li

    2015-05-01

    An enhanced membrane bioreactor (eMBR) consisting of two anoxic bioreactors (ARs) followed by an aerated membrane bioreactor (AMBR), UV-unit and a granular activated carbon (GAC) filter was employed to treat 50-100 mg/L of remazol blue BR dye. The COD of the feed was 2334 mg/L and COD:TN:TP in the feed was 119:1.87:1. A feed flow rate of 5 L/d was maintained when the dye concentration was 50 mg/L; 10 L/d of return activated sludge was recirculated to each AR from the AMBR. Once the biological system is acclimatised, 95% of dye, 99% of COD, 97% of nitrogen and 73% of phosphorus were removed at a retention time of 74.4 h. When the effluent from the AMBR was drawn at a flux rate of 6.5 L/m(2)h, the trans-membrane pressure reached 40 kPa in every 10 days. AMBR effluent was passed through the UV-unit and GAC filter to remove the dye completely.

  9. The effect of biomass immobilization support material and bed porosity on hydrogen production in an upflow anaerobic packed-bed bioreactor.

    Science.gov (United States)

    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.

  10. Characteristics of draft tube gas-liquid-solid fluidized-bed bioreactor with immobilized living cells for phenol degradation.

    Science.gov (United States)

    Fan, L S; Fujie, K; Long, T R; Tang, W T

    1987-09-01

    Biological phenol degradation in a draft tube gas-liquid-solid fluidized bed (DTFB) bioreactor containing a mixed culture immobilized on spherical activated carbon particles was investigated. The characteristics of biofilms including the biofilm dry density and thickness, the volumetric oxygen mass transfer coefficient, and the phenol removal rates under different operating conditions in the DTFB were evaluated. A phenol degradation rate as high as 18 kg/m(3)-day with an effluent phenol concentration less than 1 g/m(3) was achieved, signifying the high treatment efficiency of using a DTFB.

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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The wastewater treatment from brassylic acid manufacturing plantusing 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 10000-50000, 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.

  13. Continuous anaerobic bioreactor with a fixed-structure bed (ABFSB) for wastewater treatment with low solids and low applied organic loading content.

    Science.gov (United States)

    Mockaitis, G; Pantoja, J L R; Rodrigues, J A D; Foresti, E; Zaiat, M

    2014-07-01

    This paper describes a new type of anaerobic bioreactor with a fixed-structure bed (ABFSB) in which the support for the biomass consists of polyurethane foam strips placed along the length of the bioreactor. This configuration prevents the accumulation of biomass or solids in the bed as well as clogging and channeling effects. In this study, complex synthetic wastewater with a chemical oxygen demand of 404.4 mg O(2) L(-1) is treated by the reactor. The ABFSB, which has a working volume of 4.77 L, was inoculated with anaerobic sludge obtained from an upflow anaerobic sludge blanket bioreactor. A removal efficiency of 78 % for organic matter and an effluent pH of 6.97 were achieved. An analysis of the organic volatile acids produced by the ABFSB indicated that it operated under stable conditions during an experimental run of 36 days. The stable and efficient operation of the bioreactor was compared with the configurations of other anaerobic bioreactors used for complex wastewater treatment. The results of the study indicate that the ABFSB is a technological alternative to packed-bed bioreactors.

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

    Science.gov (United States)

    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.

  15. CFD Simulation of an Anaerobic Membrane BioReactor (AnMBR to Treat Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Laura C. Zuluaga

    2015-06-01

    Full Text Available A Computational Fluid Dynamics (CFD simulation has been developed for an Anaerobic Membrane BioReactor (AnMBR to treat industrial wastewater. As the process consists of a side-stream MBR, two separate simulations were created: (i reactor and (ii membrane. Different cases were conducted for each one, so the surrounding temperature and the total suspended solids (TSS concentration were checked. For the reactor, the most important aspects to consider were the dead zones and the mixing, whereas for the ceramic membrane, it was the shear stress over the membrane surface. Results show that the reactor's mixing process was adequate and that the membrane presented higher shear stress in the 'triangular' channel.

  16. Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel layer

    DEFF Research Database (Denmark)

    Poorasgari, Eskandar; Larsen, Poul; Zheng, Xing

    2014-01-01

    Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBRs), are generally divided into bound and free EPS. The free EPS are able to form a gel layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects...... with the amount of the humic-like substances retained during filtration as predicted by gel growth theory. A low pressure backwash could re-establish the Water flux only up to 70%....

  17. Integration of Bioreactor and Membrane Separation Processes: A Model Based Approach

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres

    to as Reverse Electro-Enhanced Dialysis (REED). Unconsumed substrate and biomass are effectively recycled to the fermenter. In the second membrane separation stage, the lactate is recovered and concentrated as lactic acid using Electrodialysis with bipolar membranes (EDBM), while sodium hydroxide is regenerated...... test. Satisfactory results are obtained regulating the pH and managing the input constraints. The design and operability of the integrated bioreactor and REED module are investigated using the developed models and control structure. The study involves two different case studies: continuous lactic acid...

  18. A vibrating membrane bioreactor (VMBR): Macromolecular transmission-influence of extracellular polymeric substances

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2009-01-01

    The vibrating membrane bioreactor (VMBR) system facilitates the possibility of conducting a separation of macromolecules (BSA) from larger biological components (yeast cells) with a relatively high and stable macromolecular transmission at sub-critical flux. This is not possible to achieve...... for a static non-vibrating membrane module. A BSA transmission of 74% has been measured in the separation of 4g/L BSA from 8 g/L dry weight yeast cells in suspension at sub-critical flux (20L/(m(2) h)). However, this transmission is lower than the 85% BSA transmission measured for at pure 4g/L BSA solution...

  19. Integration of Bioreactor and Membrane Separation Processes: A Model Based Approach

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres

    to as Reverse Electro-Enhanced Dialysis (REED). Unconsumed substrate and biomass are effectively recycled to the fermenter. In the second membrane separation stage, the lactate is recovered and concentrated as lactic acid using Electrodialysis with bipolar membranes (EDBM), while sodium hydroxide is regenerated...... test. Satisfactory results are obtained regulating the pH and managing the input constraints. The design and operability of the integrated bioreactor and REED module are investigated using the developed models and control structure. The study involves two different case studies: continuous lactic acid...

  20. Stability of immobilized Rhizomucor miehei lipase for the synthesis of pentyl octanoate in a continuous packed bed bioreactor

    Directory of Open Access Journals (Sweden)

    E. Skoronski

    2014-09-01

    Full Text Available The enzymatic synthesis of organic compounds in continuous bioreactors is an efficient way to obtain industrially important chemicals. However, few works have focused on the study of the operational conditions and the bioprocess performance. In this work, the aliphatic ester pentyl octanoate was obtained by direct esterification using a continuous packed bed bioreactor containing the immobilized enzyme Lipozyme® RM IM as catalyst. Enzymatic deactivation was evaluated under different conditions for the operational parameters substrate/enzyme ratio (5.00, 1.67, 0.83 and 0.55 mmol substrate∙min-1∙g-1enzyme and temperature (30, 40, 50 and 60 °C. The optimal condition was observed at 30 ºC, which gave the minimum enzymatic deactivation rate and the maximum conversion to the desired product, yielding approximately 60 mmols of ester for an enzyme loading of 0.5 g into the bioreactor. A first-order deactivation model showed good agreement with the experimental data.

  1. Effect of Membrane Type for the Treatment of Organized Industrial Zone (OIZ Wastewater with a Membrane Bioreactor (MBR: Batch Experiments

    Directory of Open Access Journals (Sweden)

    Oktay Özkan

    2017-08-01

    Full Text Available Organized industrial zone (OIZ wastewater is a mixed wastewater that is contributed by both municipal use and from different industrial sectors. Since MBR has advantages over conventional treatment plants, membrane types and fouling become the most important parameters in the treatment of this kind of wastewater. In this study, six different membrane types were used to find the most suitable membrane with the least resistivity to fouling. Three different microfiltration (MF and ultrafiltration (UF membranes were operated to estimate their (i membrane, (ii cake, (iii pore, and (iv total resistances. The highest total resistance was observed in a polyethersulfone (PES membrane (3.8 × 1010 m−1, while the lowest one was a UF polyvinylidene fluoride (PVDF membrane with approximately 20 times lower resistance than the highest one. PVDF membranes showed lower total resistances than PES membranes. An MF or a 250 kDa UF membrane could be operated long-term in a membrane bioreactor with the least fouling potential.

  2. Development and Optimization of AAV hFIX Particles by Transient Transfection in an iCELLis(®) Fixed-Bed Bioreactor.

    Science.gov (United States)

    Powers, Alicia D; Piras, Bryan A; Clark, Robert K; Lockey, Timothy D; Meagher, Michael M

    2016-06-01

    Adeno-associated virus (AAV) vectors are increasingly popular in gene therapy because they are unassociated with human disease, replication dependent, and less immunogenic than other viral vectors and can infect a variety of cell types. These vectors have been used in over 130 clinical trials, and one AAV product has been approved for treatment of lipoprotein lipase deficiency in Europe. To meet the demand for the increasing quantities of AAV required for clinical trials and treatment, a scalable high-capacity technology is required. Bioreactors meet these requirements but limited options are available for adherent HEK 293T/17 cells. Here we optimize the transient transfection of HEK293T/17 cells for the production of AAV human factor IX in a disposable fixed-bed bioreactor, the iCELLis(®) Nano (PALL Corporation). A fixed bed in the center of the iCELLis bioreactor is surrounded by culture medium that is pumped through the bed from the bottom of the bioreactor so that a thin film of the medium overflows the bed and is replenished with oxygen and depleted of CO2 as it returns to the surrounding medium reservoir. We show that this fixed-bed bioreactor can support as many as 2.5 × 10(8) cells/ml of fixed bed (1.9 × 10(6) cells/cm(2)). By optimizing culture and transfection parameters such as the concentration of DNA for transfection, day of harvest, size of PEI/DNA particles, and transfection medium, and adding an additional medium change to the process, we increased our yield to as high as 9.0 × 10(14) viral particles per square meter of fixed bed. We also show an average GFP transfection of 97% of cells throughout the fixed bed. These yields make the iCELLis a promising scalable technology for the clinical production of AAV gene therapy products.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. Continuous production of monoclonal antibody in a packed-bed bioreactor.

    Science.gov (United States)

    Golmakany, Naghmeh; Rasaee, Mohammad Javad; Furouzandeh, Mehdi; Shojaosadati, Seyed Abbas; Kashanian, Soheila; Omidfar, Kobra

    2005-06-01

    In the present study the growth and MAb (monoclonal antibody) production of a mouse x mouse hybridoma cell producing anti-digoxin MAb was evaluated. The hybridoma cells entrapped within the support matrix Fibra-Cel were cultured in batch and continuous mode following special protocols. Cell-culture studies were performed in a 1-litre spinner basket containing 3 g.litre-1 support matrix. Batch culture was operated with the cell density of 42x10(6) cells. During the 7 days of culture, the medium was sampled daily in order to assess glucose and MAb concentrations and the lactate dehydrogenase released into the culture medium. After a culture period of 72 h, the cell density and MAb concentration were found to be 10.4x10(7) cells/3 g of NWPF (non-woven polyester fibre) discs and 250 microg/ml respectively. This yield gradually decreased to 0.55x10(6) cells/3 g of packaging material and 60 microg/ml respectively at the end of the batch culture. In the continuous-culture studies, the batch culture was initially operated for 64.5 h and then continuous flow was started at the dilution rates of 0.15, 0.2, 0.25 and 0.3 day-1 and finally stabilized at 0.25 day-1 within 288 h (12 days). The MAb concentration at steady state was found to be 116-120 microg/day per ml, and the yield of operation was 62.5 mg/day per ml, which was 3.5 times higher than that of batch culture. In conclusion, a packed-bed bioreactor with the support matrix Fibra-Cel, operated in continuous-feeding mode, is more efficient for large-scale MAb production than a batch culture. On the other hand, by using a continuous-culture system, a better supply of nutrients and removal of inhibitory metabolites and proteolytic enzymes was obtained.

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

    Science.gov (United States)

    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.

  8. Impact of Furfural on Rapid Ethanol Production Using a Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    Mohammad J. Taherzadeh

    2013-03-01

    Full Text Available A membrane bioreactor was developed to counteract the inhibition effect of furfural in ethanol production. Furfural, a major inhibitor in lignocellulosic hydrolyzates, is a highly toxic substance which is formed from pentose sugars released during the acidic degradation of lignocellulosic materials. Continuous cultivations with complete cell retention were performed at a high dilution rate of 0.5 h−1. Furfural was added directly into the bioreactor by pulse injection or by addition into the feed medium to obtain furfural concentrations ranging from 0.1 to 21.8 g L−1. At all pulse injections of furfural, the yeast was able to convert the furfural very rapidly by in situ detoxification. When injecting 21.8 g L−1 furfural to the cultivation, the yeast converted it by a specific conversion rate of 0.35 g g−1 h−1. At high cell density, Saccharomyces cerevisiae could tolerate very high furfural levels without major changes in the ethanol production. During the continuous cultures when up to 17.0 g L−1 furfural was added to the inlet medium, the yeast successfully produced ethanol, whereas an increase of furfural to 18.6 and 20.6 g L−1 resulted in a rapidly decreasing ethanol production and accumulation of sugars in the permeate. This study show that continuous ethanol fermentations by total cell retention in a membrane bioreactor has a high furfural tolerance and can conduct rapid in situ detoxification of medium containing high furfural concentrations.

  9. Enhanced butanol production by solvent tolerance Clostridium acetobutylicum SE25 from cassava flour in a fibrous bed bioreactor.

    Science.gov (United States)

    Li, Han-Guang; Ma, Xing-Xing; Zhang, Qing-Hua; Luo, Wei; Wu, Ya-Qing; Li, Xun-Hang

    2016-12-01

    To enhance the butanol productivity and reduce the material cost, acetone, butanol, and ethanol fermentation by Clostridium acetobutylicum SE25 was investigated using batch, repeated-batch and continuous cultures in a fibrous bed bioreactor, where cassava flour was used as the substrate. With periodical nutrient supplementation, stable butanol production was maintained for about 360h in a 6-cycle repeated-batch fermentation with an average butanol productivity of 0.28g/L/h and butanol yield of 0.32g/g-starch. In addition, the highest butanol productivity of 0.63g/L/h and butanol yield of 0.36g/g-starch were achieved when the dilution rate were investigated in continuous production of acetone, butanol, and ethanol using a fibrous bed bioreactor, which were 231.6% and 28.6% higher than those of the free-cell fermentation. On the other hand, this study also successfully comfirmed that the biofilm can provide an effective protection for the microbial cells which are growing in stressful environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Performance of diatomite/iron oxide modified nonwoven membrane used in membrane bioreactor process for wastewater reclamation.

    Science.gov (United States)

    He, Yueling; Zhang, Wenqi; Rao, Pinhua; Jin, Peng

    2014-01-01

    This study describes an approach for surface modification of a nonwoven membrane by diatomite/iron oxide to examine its filterability. Analysis results showed that nonwoven hydrophilicity is enhanced. Static contact angle decreases dramatically from 122.66° to 39.33°. Scanning electron micrograph images show that diatomite/iron oxide is attached on nonwoven fiber. X-ray diffraction analysis further proves that the compound is mostly magnetite. Fourier transformed infrared spectra results reveal that two new absorption peaks might be attributed to Si-O and Fe-O, respectively. Modified and original membranes were used in double nonwoven membrane bioreactors (MBRs) for synthetic wastewater treatment. High critical flux, long filtration time, slow trans-membrane pressure rise and stable sludge volume index confirmed the advantages of modified nonwoven. Comparing with original nonwoven, similar effluent qualities are achieved, meeting the requirements for wastewater reclamation.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  13. Performance of tapered column packed-bed bioreactor for ethanol production.

    Science.gov (United States)

    Hamamci, H; Ryu, D D

    1987-06-01

    A tapered column type of bioreactor system packed with immobilized Saccharomyces cerevisiae was used to study the bioreactor performance as a function of design and operating variables. The performance of tapered column bioreactor system was found to be better than that of the conventional cylindrical column reactor system for the ethanol fermentation. The new bioreactor design alleviated problems associated with carbon dioxide evolution and provided a significantly better flow pattern for both liquid and gas phases in the bioreactor without local channelling. A mathematical simulation model, which takes into account of the axial convection and dispersion, interphase mass transfer, and apparent kinetic design parameters, was developed. The effect of radial concentration gradients on the bioreactor performance was found to be insignificant. For the reactor system studied, the maximum ethanol productivity obtained was 60 g ethanol/L gel/h, and the maximum glucose assimilation rate was 140 g glucose/L gel/h. One of the most important findings from this study was that the apparent kinetic parameters change at the glucose concentration of 2 g/L This change was found to be due to the changes in yeast physiology and metabolism. The values of V(m) (') and V(m) (') decreased from 0.8 to 0.39 g ethanol/g cell/h and from 97mM to 11mM, respectively. The substrate inhibition constant was estimated as 0.76M and the product inhibition constant was determined as 113 g ethanol/L The degree of product inhibition showed practically a linear relationship with an increasing ethanol concentration. Based on the hydro-dynamic analysis of the bioreactor system, it was found that the Peclet number, N(Pe) was not a strong function of the flow velocity at low flow rates through the bioreactor system, but its value decreased somewhat at an interstitial velocity greater than 0.03 cm/s. The tapered column bioreactor system showed a much better flow pattern of gas and liquid phases within the

  14. Towards integrated operation of membrane bioreactors: effects of aeration on biological and filtration performance.

    Science.gov (United States)

    Dalmau, M; Monclús, H; Gabarrón, S; Rodriguez-Roda, I; Comas, J

    2014-11-01

    Two experimental studies evaluated the effect of aerobic and membrane aeration changes on sludge properties, biological nutrient removal and filtration processes in a pilot plant membrane bioreactor. The optimal operating conditions were found at an aerobic dissolved oxygen set-point (DO) of 0.5 mg O2 L(-1) and a membrane specific aeration demand (SADm) of 1 m h(-1), where membrane aeration can be used for nitrification. Under these conditions, a total flow reduction of 42% was achieved (75% energy reduction) without compromising nutrient removal efficiencies, maintaining sludge characteristics and controlled filtration. Below these optimal operating conditions, the nutrient removal efficiency was reduced, increasing 20% for soluble microbial products, 14% for capillarity suction time and reducing a 15% for filterability. Below this DO set-point, fouling increased with a transmembrane pressure 75% higher. SADm below 1 m h(-1) doubled the values of transmembrane pressure, without recovery after achieving the initial conditions.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 filters in water treatment.

  20. The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors.

    Science.gov (United States)

    Tirunehe, Gossaye; Norddahl, B

    2016-04-01

    Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air-water and air-CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas-liquid mediums. CMC solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas-liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (U(G)) range of 0.0004-0.0025 m/s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (K(L)a) by a factor of 1.2-1.9 compared to the flat sheet membrane.

  1. Performance of membrane bioreactors used for the treatment of wastewater from the chemical and textile industries.

    Science.gov (United States)

    Baumgarten, S; Schröder, H F; Pinnekamp, J

    2006-01-01

    Within the scope of the study, nine waste waters from the chemical and textile industries were treated in bench-scale (laboratory scale) and small-scale (pilot scale) membrane bioreactors. Depending on wastewater characteristics, the resulting performance varied significantly. It was observed that MBR effectiveness was determined primarily by the degree of biodegradability of the wastewater. In the course of several months of operation, no significant changes associated with the complete retention of the biomass by the membranes were observed. In some cases, it was possible to improve effluent quality by using smaller molecular separation sizes. The flux performance of the membrane modules was dependent on wastewater composition. Occasionally, non-degradable macromolecular substances concentrated in the bioreactor, resulting in strongly reduced filterability and flow performance of the membrane modules, consequently also reducing the economic viability of the process. The results demonstrate that wastewater-specific pilot tests are absolutely necessary, in particular if the technology is to be used for new applications.

  2. Continuous Ethanol Production with a Membrane Bioreactor at High Acetic Acid Concentrations

    Directory of Open Access Journals (Sweden)

    Päivi Ylitervo

    2014-07-01

    Full Text Available The release of inhibitory concentrations of acetic acid from lignocellulosic raw materials during hydrolysis is one of the main concerns for 2nd generation ethanol production. The undissociated form of acetic acid can enter the cell by diffusion through the plasma membrane and trigger several toxic effects, such as uncoupling and lowered intracellular pH. The effect of acetic acid on the ethanol production was investigated in continuous cultivations by adding medium containing 2.5 to 20.0 g·L−1 acetic acid at pH 5.0, at a dilution rate of 0.5 h−1. The cultivations were performed at both high (~25 g·L−1 and very high (100–200 g·L−1 yeast concentration by retaining the yeast cells inside the reactor by a cross-flow membrane in a membrane bioreactor. The yeast was able to steadily produce ethanol from 25 g·L−1 sucrose, at volumetric rates of 5–6 g·L−1·h−1 at acetic acid concentrations up to 15.0 g·L−1. However, the yeast continued to produce ethanol also at a concentration of 20 g·L−1 acetic acid but at a declining rate. The study thereby demonstrates the great potential of the membrane bioreactor for improving the robustness of the ethanol production based on lignocellulosic raw materials.

  3. Enhancing inhibited fermentations through a dynamic electro-membrane bioreactor

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Garde, Arvid; Rype, Jens-Ulrik

    Reverse Electro-Enhanced Dialysis (REED) has been shown to intensify fermentations which are impaired by an ionic product inhibition. Productivity can be greatly enhanced by the in situ product removal from the cultivation broth. The REED process has been tested for different applications, where......, it is interesting to reveal to which extend the REED module can facilitate the pH control in the fermenter. In this case, the membrane and reactor unit interactions are exploited to substantially increase the lactate productivity and substrate utilization compared to a conventional fermentation with a crude control...

  4. Determination and discussion hydraulic retention time in membrane bioreactor system

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the microorganism kinetic model, the formulafor computing hydraulic retention time in a membrane bioreactorsystem (MBR) is derived. With considering HRT as an evaluationindex a combinational approach was used to discuss factors whichhave an effect on MBR. As a result, the influencing factors werelisted in order from strength to weakness as: maximum specificremoval rate K, saturation constant Ks, maintenance coefficient m,Moreover, the formula was simplified, whose parameters wereexperimentally determined in petrochemical wastewater treatment. The simplified formula is (=1.1((1/(-1)(Ks+S)/KX0, forpetrochemical wastewater treatment K and Ks equaled 0.185 and154.2, respectively.

  5. Technical and economic balance for membrane bioreactor technology's implementation; Criterios tecnicos-economicos para la implantacion de la tecnologia de bioreactores de membrana

    Energy Technology Data Exchange (ETDEWEB)

    Lopetegui Garnika, J.; Trouve, E.

    2004-07-01

    Comparing with conventional technologies, the membrane bioreactor has a lot of important, advantages: effluent quality, decreased sludge production, less space requirement, etc. In order to establish the technology, it is completely necessary to do a hole balance (small footprint, reusing, running-cost, maintenance, etc) and to choose between the most appropriate membrane configuration (external or submerged), which will depend mainly on the flow and organic matter concentration on waste water. That is the way in which capital cost and running cost (including membrane replacement) became competitive in both urban and industrial waste waters. (Author) 10 refs.

  6. The cost of a package plant membrane bioreactor.

    Science.gov (United States)

    Fletcher, H; Mackley, T; Judd, S

    2007-06-01

    The capital and operating costs associated with a small package plant MBR for small-scale domestic duty has been appraised based on a medium-strength municipal wastewater. The three main membrane configurations were considered, these being multi-tube, hollow fibre and flat sheet, with the most appropriate plant design chosen for each configuration. The analysis proceeded via a consideration of the estimated amortised capital costs of the plant individual components and their installation, coupled with operating costs based largely on energy demand and residuals management. Energy demand was calculated from aeration and pumping costs, with aeration based on a combination of empirical relationships for membrane aeration and mass balance, and the modified Activated Sludge Model version 2 used for estimating tank size and sludge generation. Results indicate that it is possible to produce a single household MBR at a capital cost similar to the current market cost for package treatment plants. Desludging and maintenance of these plants is similar but power requirements for an MBR are around 4 times that associated with more conventional package plants. Economies of scale exist from 6-20 p.e. plants but above 20 p.e. there is little cost difference per head, due to the design assumptions made. CAPEX and OPEX are to some extent interchangeable; reductions in CAPEX are associated with an increase in OPEX and vice versa. Whilst costs are high, the market for package MBRs is significantly influenced by the recycling potential of the effluent produced.

  7. Temporal Changes in Extracellular Polymeric Substances on Hydrophobic and Hydrophilic Membrane Surfaces in a Submerged Membrane Bioreactor

    KAUST Repository

    Matar, Gerald Kamil

    2016-03-02

    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/m2.h in the same lab-scale MBR fed with synthetic wastewater. In addition, identical membrane modules without permeate production (0 L/m2.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 considered

  8. Evaluation of biological nutrient removal from wastewater by Twin Circulating Fluidized Bed Bioreactor (TCFBBR) using a predictive fluidization model and AQUIFAS APP.

    Science.gov (United States)

    Andalib, Mehran; Nakhla, George; Sen, Dipankar; Zhu, Jesse

    2011-02-01

    A two-phase and three-phase predictive fluidization model based on the characteristics of a system such as media type and size, flow rates, and reactor cross sectional area was proposed to calculate bed expansion, solid, liquid and gas hold up and specific surface area (SSA) of the biofilm particles. The model was subsequently linked to 1d AQUIFAS APP software (Aquaregen) to model biological nutrient removal in two phase (anoxic) and three phase (aerobic) fluidized bed bioreactors. The credibility of the proposed model for biological nutrient removal was investigated using the experimental data from a Twin Circulating Fluidized Bed Bioreactors (TCFBBR) treating synthetic and municipal wastewater. The SSA of bio-particles and volume of the expanded bed were simulated as a function of operational parameters. Two-sided t-tests demonstrated that simulated SCOD, NH(4)-N, NO(3)-N, TN, VSS and biomass yields agreed with the experimental values at the 95% confidence level.

  9. A novel composite conductive microfiltration membrane and its anti-fouling performance with an external electric field in membrane bioreactors

    Science.gov (United States)

    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. Evaluation of membrane bioreactor for advanced treatment of industrial wastewater and reverse osmosis pretreatment

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  12. Development of a Comprehensive Fouling Model for a Rotating Membrane Bioreactor System Treating Wastewater

    Directory of Open Access Journals (Sweden)

    Parneet Paul

    2015-01-01

    Full Text Available Membrane bioreactors (MBRs are now main stream wastewater treatment technologies. In recent times, novel pressure driven rotating membrane disc modules have been specially developed that induce high shear on the membrane surface, thereby reducing fouling. Previous research has produced dead-end filtration fouling model which combines all three classical mechanisms that was later used by another researcher as a starting point for a greatly refined model of a cross flow side-stream MBR that incorporated both hydrodynamics and soluble microbial products’ (SMP effects. In this study, a comprehensive fouling model was created based on this earlier work that incorporated all three classical fouling mechanisms for a rotating MBR system. It was tested and validated for best fit using appropriate data sets. The initial model fit appeared good for all simulations, although it still needs to be calibrated using further appropriate data sets.

  13. Effect of powdered activated carbon on integrated submerged membrane bioreactor-nanofiltration process for wastewater reclamation.

    Science.gov (United States)

    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.

  14. Full-scale validation of an air scour control system for energy savings in membrane bioreactors.

    Science.gov (United States)

    Monclús, Hèctor; Dalmau, Montserrat; Gabarrón, Sara; Ferrero, Giuliana; Rodríguez-Roda, Ignasi; Comas, Joaquim

    2015-08-01

    Membrane aeration represents between 35 and 50% of the operational cost of membrane bioreactors (MBR). New automatic control systems and/or module configurations have been developed for aeration optimization. In this paper, we briefly describe an innovative MBR air scour control system based on permeability evolution and present the results of a full-scale validation that lasted over a 1-year period. An average reduction in the air scour flow rate of 13% was achieved, limiting the maximum reduction to 20%. This averaged reduction corresponded to a decrease in energy consumption for membrane aeration of 14% (0.025 kWh m(-3)) with maximum saving rates of 22% (0.04 kWh m(-3)). Permeability and fouling rate evolution were not affected by the air scour control system, as very similar behavior was observed for these variables for both filtration lines throughout the entire experimental evaluation period of 1 year.

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

    Science.gov (United States)

    Hao, L; Liao, B Q

    2015-01-01

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

  16. REUSE OF DAIRY WASTEWATER TREATED BY MEMBRANE BIOREACTOR AND NANOFILTRATION: TECHNICAL AND ECONOMIC FEASIBILITY

    Directory of Open Access Journals (Sweden)

    L. H. Andrade

    2015-09-01

    Full Text Available AbstractThis study evaluated the technical and economic feasibility of membrane bioreactors (MBR followed by nanofiltration (NF for dairy wastewater treatment in order to reuse the treated effluent. It was observed that the MBR efficiently removed the organic matter and color of the feed effluent; however, due to the high concentration of dissolved solids in the permeate, it was necessary to use nanofiltration as a polishing step. The final treated effluent could be reused in the industry for cooling, steam generation and cleaning of external areas. A preliminary economic analysis showed the feasibility of the proposed system. The internal rate of return was greater than or equal to 32% when membrane lifespan was at least 2 years and the depreciation time was 15 years. The total cost of the proposed treatment system ranged from R$ 9.99/m3 to R$ 6.82/m3, depending on membrane lifespan.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  19. Treating Opaque Beer Wastewater Using a Novel Internal Circulation Membrane Bioreactor

    Institute of Scientific and Technical Information of China (English)

    TAN Xin; REN Yanshuang; ZHAO Lin

    2006-01-01

    An innovative internal circulation membrane bioreactor( ICMBR)treating traditional opaque beer brewery wastewater was introduced. Beer wastewater from Tianjin Huarun Brewhouse wastaken as the influent. The removal efficiency of suspended solid, chemical oxygen demand, total nitrogen and ammonia nitrogen were studied with the changeable hard real time design method, organic loading rate and nutrition elements. The average percentage reduction in chemical oxygen demand achieved 90%. The total nitrogen and ammonia nitrogen were also reduced by 90% and 95%,respectively. The results indicate that the outlet of ICMBR meets the requirements of the environment landscape recycling use.

  20. Energy Consumption Related to Shear Stress for Membrane Bioreactors Used for Wastewater Treatment

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Bérube, P.R.

    2011-01-01

    . A linear empirical correlation between the average shear stress and the blower power per unit of permeate was made. 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. It was found that this relationship is over predictive by 28 % compared to experimental measurements and CFD results. Therefore a correction factor is included on the relationship to account for the membrane placed inside the bioreactor....

  1. Application of electrochemical processes to membrane bioreactors for improving nutrient removal and fouling control.

    Science.gov (United States)

    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.

  2. The effect of organic loading on bacterial community composition of membrane biofilms in a submerged polyvinyl chloride membrane bioreactor.

    Science.gov (United States)

    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.

  3. Comparison of Four Types of Membrane Bioreactor Systems in Terms of Shear Stress over the Membrane Surface using Computational Fluid Dynamics

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby

    2013-01-01

    Membrane bioreactors (MBRs) have been used successfully in biological wastewater treatment to solve the perennial problem of effective solids–liquid separation. A common problem with MBR systems is clogging of the modules and fouling of the membrane, resulting in frequent cleaning and replacement...

  4. Performance assessment and hydrodynamic analysis of a submerged membrane bioreactor for treating dairy industrial effluent.

    Science.gov (United States)

    K, Praneeth; Moulik, Siddhartha; Vadthya, Pavani; Bhargava, Suresh K; Tardio, James; S, Sridhar

    2014-06-15

    Submerged membrane bioreactor (SMBR) is a relatively advanced technology for waste water treatment that involves integrated aerobic and anaerobic biological processes with membrane filtration. In the present investigation, hydrophobic polyvinylidene fluoride (PVDF) and hydrophilic polyacrylonitrile (PAN) hollow fiber (HF) membranes were tested in an indigenously fabricated SMBR for dairy effluent treatment under aerobic conditions using mixed microbial consortia. Effect of operating parameters such as suction pressure, degree of aeration and trans-membrane pressure (TMP) on membrane performance in terms of flux, rejection of turbidity, BOD and COD besides fouling characteristics was investigated. The observed optimum permeabilities of PVDF and PAN HF membranes were approximately 108 and 115 LMH bar(-1) with high extent of impurity removal. The rejection of COD was found to be 93% for PVDF and 91% for PAN HF membranes whereas corresponding rejection of BOD was observed to be 92% and 86%. A two-dimensional comprehensive model was developed to predict the hydrodynamic profile inside the module. Regression analysis revealed that the simulation results agreed well with experimental data.

  5. Characterization of biofouling in a lab-scale forward osmosis membrane bioreactor (FOMBR).

    Science.gov (United States)

    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.

  6. Influence of membrane fouling reducers (MFRs) on filterability of disperse mixed liquor of jet loop bioreactors.

    Science.gov (United States)

    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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Biological treatment of mixtures of toluene and n-hexane vapours in a hollow fibre membrane bioreactor.

    Science.gov (United States)

    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.

  8. Study of the degradation of dyes by MnP of Phanerochaete chrysosporium produced in a fixed-bed bioreactor.

    Science.gov (United States)

    Moldes, D; Rodríguez Couto, S; Cameselle, C; Sanromán, M A

    2003-04-01

    The production of ligninolytic enzymes by the fungus Phanerochaete chrysosporium in a fixed-bed tubular bioreactor, filled with cubes of nylon sponge, operating in semi-solid-state conditions, was studied. Maximum individual manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of 1293 and 225 U/l were detected. The in vitro decolourisation of two structurally different dyes (Poly R-478, crystal violet) by the extracellular liquid obtained in the above-mentioned bioreactor was monitored in order to determine its degrading capability. The concentration of some compounds (sodium malonate, manganese sulphate) from the reaction mixture was optimised in order to maximise the decolourisation levels. A percentage of Poly R-478 decolourisation of 24% after 15 min of dye incubation was achieved. On the other hand, a methodology for a long treatment of these dyes based on the continuous addition of MnP enzyme and H(2)O(2) was developed. Moreover, this enzymatic treatment was compared with a photochemical decolourisation process. The former allowed to maintain the degradation rate almost constant for a long time, resulting in a decolourisation percentage of 70% and 30% for crystal violet and Poly R-478, respectively, after 2 h of treatment. As for the latter, it was not able to degrade Poly R-478, whereas crystal violet reached a degradation of 40% in 2 h.

  9. Mathematical modelling and optimization of hydrogen continuous production in a fixed bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Palazzi, E.; Perego, P.; Fabiano, B. [University of Genoa, Genova (Italy). Chemical and Process Engineering Department ' G.B. Bonino'

    2002-09-01

    The purpose of this paper is to investigate, both theoretically and experimentally, hydrogen production from agro-industrial by-products using a continuous bioreactor packed with a mixture of spongy and glass beads and inoculated with Enterobacter aerogenes. Replicated series of experimental runs were performed to study the effects of residence time on hydrogen evolution rate and to characterize the critical conditions for the wash out, as a function of the inlet glucose concentration and of the fluid superficial velocity. A further series of experimental runs was focused on the effects of both residence time and inlet glucose concentration over hydrogen productivity. A kinetic model of the process was developed and showed good agreement with experimental data, thus representing a potential tool to design a large-scale fermenter. In fact, the model was applied to the optimal design of a bioreactor suitable of feeding a phosphoric acid fuel cell of a target power. (author)

  10. Iron and phosphorus speciation in Fe-conditioned membrane bioreactor activated sludge.

    Science.gov (United States)

    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.

  11. Development and validation of a bioartificial liver device with fluidized bed bioreactors hosting alginate-encapsulated hepatocyte spheroids.

    Science.gov (United States)

    Figaro, S; Pereira, U; Rada, H; Semenzato, N; Pouchoulin, D; Legallais, C

    2015-08-01

    Acute and acute-on-chronic liver failure are associated to high mortality when transplantation is not possible. The lack of donors has resulted in an important demand for liver support devices. This paper describes the design and validation of a new bioartificial liver (BAL) device including fluidized bed bioreactors hosting alginate-encapsulated hepatocytes spheroids. To ensure the efficacy of the BAL and the safety of the patients, a complex extracorporeal circulation was designed to be compatible with a commercial medical device, the Prismaflex(®) monitor, already used in intensive care units. Preclinical studies on large animal show that the treatment was well tolerated in terms of hemodynamics considerations. A method using non adhesive coating in petri dish led to the production of large amount of viable spheroids in vitro that were further encapsulated to follow up bioartificial liver activity during four days.

  12. Control and optimization of Clostridium tyrobutyricum ATCC 25755 adhesion into fibrous matrix in a fibrous bed bioreactor.

    Science.gov (United States)

    Jiang, Ling; Wang, Jufang; Liang, Shizhong; Cai, Jin; Xu, Zhinan

    2011-09-01

    The great performance of a fibrous bed bioreactor (FBB) is mainly dependent on the cell adhesion and immobilization into the fibrous matrix. Therefore, understanding the mechanism and factors controling cell adhesion in the fibrous matrix is necessary to optimize the FBB setup and further improve the fermentability. The adhesion behavior of a strain of Clostridium tyrobutyricum isolated from an FBB was studied, which was proven to be affected by the different environmental conditions, such as growth phase of cells, pH, ionic strength, ionic species, and composition of media. Our results also suggested that electrostatic interactions played an important role on bacteria adhesion into the fibrous matrix. This study demonstrated that the compositions of fermentation broth would have a significant effect on cell adhesion. Consequently, a two-stage glucose supply control strategy was developed to improve the performance of FBB with higher viable cell density in the operation of the FBB setup.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Removal of Rotavirus and Bacteriophages by Membrane Bioreactor Technology from Sewage.

    Science.gov (United States)

    Hmaied, F; Keskes, S; Jebri, S; Amri, I; Yahya, M; Loisy-Hamon, F; Lebeau, B; Hamdi, M

    2015-11-01

    Human enteric viruses constitute a public health concern due to their low infectious dose and their resistance to environmental factors and to inactivation processes. We aimed at assessing the performance of a laboratory scale Submerged membrane bioreactor (SMBR) treating abattoir wastewaters for Rotavirus (RV) and total coliphages removal. We also aimed at evaluating removal efficiency of enteric viruses through conventional activated sludge treatment by measuring concentrations of total coliphages, considered as fecal and viral contamination indicators, with double-layer agar technique. The Log10 reduction values of bacteriophages ranged from 1.06 to 1.47. Effluents were analyzed to investigate and quantify RV, hepatitis A virus (HAV), Hepatitis E virus (HEV), Noroviruses genogroup I (NoV GI) and genogroup II (NoVGII), and Enterovirus (EV) by real-time PCR, using standardized detection kits (ceeramTools detection kits(®)). All effluent samples were positive for RV; concentrations ranged from 5.2 × 10(5) to 1.3 × 10(7) genome copies/L. These results highlight the inefficiency of conventional biological process for viral removal. A complete removal of RV during Membrane Bioreactor treatment was obtained. To the best of our knowledge, this is the first study providing an evidence of removal of RV simultaneously with total coliphages by SMBR.

  16. Simultaneous nitrogen and phosphor removal in an aerobic submerged membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-wei; WU Zhi-chao; GU Guo-wei; YU Guo-ping; MA Lu-ming

    2006-01-01

    Simultaneous nitrification and denitrification (SND) effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids (MLSS) 19-20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor (MBR) and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2-0.3 mg/L. The main mechanisms governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate (PFS) addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances (EPS) of mixed liquor.

  17. [A Comparative Study on Two Membrane Bioreactors for the Treatment of Digested Piggery Wastewater].

    Science.gov (United States)

    Shui, Yong; Kawagishi, Tomoki; Song, Xiao-yan; Liu, Rui; Chen, Lü-jun

    2015-09-01

    With high concentrations of chemical oxygen demand (COD) and ammonium while low ratio of COD to total nitrogen (TN), digested piggery wastewater is difficult to treat using conventional biological methods. In this study, a biofilm membrane bioreactor (BF-MBR) and a traditional type of membrane bioreactor (MBR) were parallel operated to treat digested piggery wastewater, and the pollutant removal performance were compared at influent COD/TN ratios of 1. 0 ± 0. 2 and 2. 3 ± 0. 4, respectively. The results showed that the effluent quality in both reactors was poor and unstable when the influent COD/TN ratio was 1. 0 ± 0. 2. The effluent quality and stability were greatly improved as the influent COD/TN ratio was increased to 2. 3 ± 0. 4. The removal rates of COD and ammonium were respectively 92. 3% ± 2. 4% and 97. 5% ± 4. 1% in BF-MBR, slightly higher than 91. 9% ± 1. 5% and 91. 2% ± 14. 0% in MBR. Benefited from the biofilm, 36. 7% ± 19. 5% of TN and 54. 0% ± 18. 9% of TP were removed by BF-MBR, significantly higher than the respective values of 19. 2% ± 12. 4% and 29. 0% ± 18. 1% by MBR. Moreover, BF-MBR consumed less than 40% of the alkaline chemicals as MBR. BF-MBR was considered more suitable for treatment of digested piggery wastewater due to its better pollutant removal performance and low consumption of alkaline.

  18. Removal of pharmaceuticals and personal care products in a membrane bioreactor wastewater treatment plant.

    Science.gov (United States)

    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.

  19. Production of carboxylic acids from hydrolyzed corn meal by immobilized cell fermentation in a fibrous-bed bioreactor.

    Science.gov (United States)

    Huang, Yu Liang; Wu, Zetang; Zhang, Likun; Cheung, Chun Ming; Yang, Shang-Tian

    2002-03-01

    Corn meal hydrolyzed with amylases was used as the carbon source for producing acetic, propionic, and butyric acids via anaerobic fermentations. In this study, corn meal, containing 75% (w/w) starch, 20% (w/w) fibers, and 1.5% (w/w) protein, was first hydrolyzed using amylases at 60 degrees C. The hydrolysis yielded approximately 100% recovery of starch converted to glucose and 17.9% recovery of protein. The resulting corn meal hydrolyzate was then used, after sterilization, for fermentation studies. A co-culture of Lactococcus lactis and Clostridium formicoaceticum was used to produce acetic acid from glucose. Propionibacterium acidipropionici was used for propionic acid fermentation, and Clostridium tyrobutylicum was used for butyric acid production. These cells were immobilized on a spirally wound fibrous matrix packed in a fibrous-bed bioreactor (FBB) developed for multi-phase biological reactions or fermentation. The bioreactor was connected to a stirred-tank fermentor that provided pH and temperature controls via medium circulation. The fermentation system was operated at the recycle batch mode. Temperature and pH were controlled at 37 degrees C and 7.6, respectively, for acetic acid fermentation, 32 degrees C and 6.0, respectively, for propionic acid fermentation, and 37 degrees C and 6.0, respectively, for butyric acid production. The fermentation demonstrated a yield of approximately 100% and a volumetric productivity of approximately 1 g/(1 h) for acetic acid production. The propionic acid fermentation achieved an approximately 60% yield and a productivity of 2.12 g/(1 h), whereas the butyric acid fermentation obtained an approximately 50% yield and a productivity of 6.78 g/(1 h). These results were comparable to, or better than those fermentations using chemically defined media containing glucose as the substrate, suggesting that these carboxylic acids can be efficiently produced from direct fermentation of corn meal hydrolyzate. The corn fiber present

  20. Nutrient utilization and oxygen production by Chlorella Vulgaris in a hybrid membrane bioreactor and algal membrane photobioreactor system

    KAUST Repository

    Najm, Yasmeen

    2017-02-17

    This work studied oxygen production and nutrient utilization by Chlorella Vulgaris at different organic/inorganic carbon (OC/IC) and ammonium/nitrate (NH4+-N/NO3--N) ratios to design a hybrid aerobic membrane bioreactor (MBR) and membrane photobioreactor (MPBR) system. Specific oxygen production by C. vulgaris was enough to support the MBR if high growth is accomplished. Nearly 100% removal (or utilization) of PO43--P and IC was achieved under all conditions tested. Optimal growth was achieved at mixotrophic carbon conditions (0.353 d-1) and the highest NH4+-N concentration (0.357 d-1), with preferable NH4+-N utilization rather than NO3--N. The results indicate the potential of alternative process designs to treat domestic wastewater by coupling the hybrid MBR - MPBR systems.

  1. Conidia production by Beauveria bassiana (for the biocontrol of a diamondback moth) during solid-state fermentation in a packed-bed bioreactor.

    Science.gov (United States)

    Kang, S W; Lee, S H; Yoon, C S; Kim, S W

    2005-01-01

    Conidia of Beauveria bassiana CS-1, which have the potential for the control of the diamondback moth (Plutella xylostella), were produced by solid-state fermentation (SSF) using a packed-bed bioreactor with rice straw and wheat bran. As the packing density and the bed height were increased, the production of conidia decreased. In a packed-bed bioreactor under no aeration and no addition of polypropylene (PP) foam (control), the total average of conidia was 4.9 x 10(8) g-1. The production of conidia was affected more by the addition of PP foam as an inert support than forced aeration and was approx. 23 times higher than that of the control. The total average of conidia produced by B. bassiana was 1.1-1.2 x 10(10) g-1 .

  2. Performance assessment of a submerged membrane bioreactor using a novel microbial consortium.

    Science.gov (United States)

    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.

  3. Submerged membrane adsorption bioreactor as a pretreatment in seawater desalination for biofouling control.

    Science.gov (United States)

    Jeong, Sanghyun; Naidu, Gayathri; Vigneswaran, Saravanamuthu

    2013-08-01

    Submerged membrane adsorption bioreactor (SMABR) was investigated as a pretreatment to reverse osmosis (RO). SMABR removed organic matter by adsorption and biological degradation. At a powder activated carbon (PAC) residence time of 66 d (1.5% of PAC replacement daily), higher organic removal was achieved with removal of a majority of biopolymers (94-97%) and humics (71-76%). A continuous MBR operation with the optimal PAC residence time of 66 d was conducted and compared with MBR with no PAC replenishment in terms of the removal of organic and microbes. High removal of organics of up to 72% was maintained with only a marginal increment of trans-membrane pressure and stable bioactivity (total cell number and adenosine tri-phosphate) during the 50d of operation. The SMABR was found to be a sustainable biological pretreatment to RO with only a small amount of PAC requirement (2.14 g of PAC/m(3) of seawater treated).

  4. On controllability of an integrated bioreactor and periodically operated membrane separation process

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Jørgensen, Sten Bay; Jonsson, Gunnar Eigil

    to understand the controlled operation of the integrated process, it is convenient to use a model based approach supported by experimental evidence. Recently, an integrated bioreactor and electrically driven membrane separation process (Reverse Electro- Enhanced Dialysis - REED) has been proposed as a method...... for intensification of lactic acid fermentation (Rype, 2003). This fermentation has been studied extensively driven by an increasing number of applications of the potential fermentation products. The main limitation of lactic acid bioproduction is that lactic acid bacteria normally are impaired by product inhibition...... at a certain lactate concentration level. Hence, productivity can be enhanced by the in situ lactate removal from the cultivation broth during pH controlled fermentation. This can be done by means of ion exchange membranes and electrical potential gradients. The novelty of the integrated process lies...

  5. Membrane bioreactor wastewater treatment plants reveal diverse yeast and protist communities of potential significance in biofouling.

    Science.gov (United States)

    Liébana, Raquel; Arregui, Lucía; Belda, Ignacio; Gamella, Luis; Santos, Antonio; Marquina, Domingo; Serrano, Susana

    2015-01-01

    The yeast community was studied in a municipal full-scale membrane bioreactor wastewater treatment plant (MBR-WWTP). The unexpectedly high diversity of yeasts indicated that the activated sludge formed a suitable environment for them to proliferate, with cellular concentrations of 2.2 ± 0.8 × 10(3) CFU ml(-1). Sixteen species of seven genera were present in the biological reactor, with Ascomycetes being the most prevalent group (93%). Most isolates were able to grow in a synthetic wastewater medium, adhere to polyethylene surfaces, and develop biofilms of variable complexity. The relationship between yeast populations and the protists in the MBR-WWTP was also studied, revealing that some protist species preyed on and ingested yeasts. These results suggest that yeast populations may play a role in the food web of a WWTP and, to some extent, contribute to membrane biofouling in MBR systems.

  6. Membrane bioreactor: A mini review on recent R&D works.

    Science.gov (United States)

    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.

  7. Production of solvents (ABE fermentation) from whey permeate by continuous fermentation in a membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Ennis, B.M.; Maddox, I.S.

    1988-12-09

    A continuous bioreactor where cells were recycled using a cross-flow microfiltration (CFM) membrane plant was investigated for the production of solvents (ABE fermentation) from whey permeate using Clostridium acetobutylicum P262. A tubular CFM membrane plant capable of being backflushed was used. The continuous fermentations were characterized by cyclic solventogenic and acidogenic behaviour, and ultimately degenerated to an acidogenic state. Steady-state solvent production was obtained for only short periods. This degeneration is attributed to the complex morphological behaviour of this strain of organism on this substrate. It is postulated that to achieve steady-state solvent production over extended periods of time, it is necessary to maintain a balance among the various morphological cell forms, i.e. acid-producing vegetative cells, solvent-producing clostridial cells, and inert forms, e.g. spores.

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

    Science.gov (United States)

    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.

  9. A new flat sheet membrane bioreactor hybrid system for advanced treatment of effluent, reverse osmosis pretreatment and fouling mitigation.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Treatment of N-Nitrosodimethylamine (NDMA) in Groundwater Using a Fluidized Bed Bioreactor

    Science.gov (United States)

    2014-01-01

    system while the balance is recycled back to the suction of the influent pump. An in-bed biomass separation device controls bed height growth by...proceeded through the FBR treatment system to the gravity feed drain line. Any necessary repairs or improvements were conducted at this time prior to the

  11. Kinetics of nitrate and perchlorate removal and biofilm stratification in an ion exchange membrane bioreactor.

    Science.gov (United States)

    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.

  12. Advanced Wastewater Treatment Engineering—Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling

    Directory of Open Access Journals (Sweden)

    Parneet Paul

    2016-01-01

    Full Text Available 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.

  13. Advanced Wastewater Treatment Engineering-Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling.

    Science.gov (United States)

    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.

  14. Retention of Silica Nanoparticles in a Lab-Scale Membrane Bioreactor: Implications for Process Performance and Membrane Fouling

    Directory of Open Access Journals (Sweden)

    Mark Larracas Sibag

    2016-07-01

    Full Text Available In conventional activated sludge (CAS involving aerobic biological processes, the retention of silica nanoparticles (SiO2 NPs has no detrimental effect on chemical oxygen demand (COD and ammonia nitrogen (NH3–N removal. However, for the membrane bioreactor (MBR system, which is also based on the activated sludge process in addition to the membrane separation process, it has implications not only on the process performance but also on membrane fouling. To investigate these two implications in lab-scale experiments, we continuously operated a control MBR and two experimental MBRs, in which the 28 nm SiO2 NPs and 144 nm SiO2 NPs were added separately to the influent at a final concentration of 100 mg/L. Although the retention of SiO2 NPs in the MBR, as confirmed by dynamic light scattering (DLS analysis, did not compromise the COD and NH3–N removal, it resulted in substantial increases in the transmembrane pressure (TMP suggesting the onset of membrane fouling. Analyses by batch-dead end filtration revealed the same fouling trend as observed during the continuous MBR experiments; membrane fouling is aggravated in the presence of SiO2 NPs. This was evident from permeate flux decline of between 30% and 74% at very low TMP (5 kPa and the further increases in the total resistance.

  15. Removal of azo dye acid orange 7 using aerobic membrane bioreactor

    Directory of Open Access Journals (Sweden)

    A.H. Konsowa

    2011-03-01

    Full Text Available A laboratory scale aerobic membrane bioreactor (MBR using a submerged microfiltration (MF; hollow-fiber membrane was used for treating wastewater polluted with azo dye acid orange 7 (AO7. Initial dye concentrations studied were from 50 to 400 mg/l with a COD ranging from 95 to 550 mg O2/l and hydraulic retention times (HRT 4, 6, 8 and 24 h. Results showed that the biological process was responsible for almost 60–80% of COD removal and almost all the removal of AO7 color. Membrane microfiltration merely balanced the unstable biological treatment of COD and demonstrated almost no contribution to AO7 color removal. Trans-membrane pressure (TMP increased with time, and with the increase of dye concentration reaching a maximum of 4.175 psi. Scanning electron microscope (SEM images of the membrane’s filament were taken and compared with a SEM image of a virgin membrane; clear deformation in membrane’s pore structure could be noticed as well as scale formation on the outer surface of filaments, foulants were determined using the energy dispersive X-ray analysis (EDX.

  16. Integration of micro-filtration into osmotic membrane bioreactors to prevent salinity build-up.

    Science.gov (United States)

    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.

  17. A membrane bioreactor for the removal of dimethyl sulphide and toluene from waste air.

    Science.gov (United States)

    Van Langenhove, H; De Bo, I; Jacobs, P; Demeestere, K; Dewulf, J

    2004-01-01

    In biotrickling filters, mass transfer of hydrophobic compounds is the limiting factor. Biofilters are static systems, and so control and regulation of operational parameters such as pH and nutrient supply can be a problem. In membrane bioreactors, these drawbacks can be avoided. The hydrophobic membrane separates the waste air from the aqueous phase, thus avoiding mass-transfer limitation, while pH and nutrient supply can be directly controlled. In this contribution, an overview will be given of results obtained during a four-year project. First, the physical chemical characteristics (solubility, permeability, diffusivity) and microbial adhesion of different membranes were tested. This led to the selection of a composite membrane consisting of a porous polyvinylidenefluoride (PVDF) support layer coated with a thin (1 or 2.5 microm) dense polydimethylsiloxane (PDMS) top layer. This membrane was mounted into a module provided with four parallel rectangular channels for gas flow (in contact with the porous layer) and nutrient solution (in contact with the dense layer) respectively. After inoculation, a biofilm developed on the dense layer. Experiments were performed with dimethyl sulphide and toluene as target VOCs. Operational characteristics such as elimination capacity as a function of the volumetric load and residence time, effect of nutrient supply, long-term performance) were determined. Mass transfer was studied by measuring concentration profiles along the channels of the module in different conditions.

  18. Anaerobic membrane bioreactor (AnMBR) for bamboo industry wastewater treatment.

    Science.gov (United States)

    Wang, Wei; Yang, Qi; Zheng, Shuangshuang; Wu, Donglei

    2013-12-01

    Bamboo industry wastewater (BIWW) poses severe environmental problems because of its high organic matter content. In this study, anaerobic membrane bioreactor (AnMBR) was applied for BIWW treatment. During the start-up stage, the system presented an effective degradation with a final COD removal of 91%. Compared to the intermittent mode, a higher membrane rejection (45% COD, 60% NH3-N) was obtained when the system was operated continuously. N2 flushing was applied for membrane cleaning, and the cleaning efficiency was significantly influenced by the hydraulic retention time (HRT). While operated under HRT ≥ 5 d, membrane fouling could be effectively controlled. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis indicated the membrane top area suffered the most serious fouling. Gel permeation chromatography (GPC) and gas chromatography-mass spectrometry (GC-MS) analyses revealed most organic matter in BIWW was eliminated by AnMBR. However, benzene and fluoro derivatives were detected in the permeate as the by-products.

  19. Role of microorganism growth phase in the accumulation and characteristics of biomacromolecules (BMM) in a membrane bioreactor

    DEFF Research Database (Denmark)

    Zhou, Zhongbo; Meng, Fangang; Liang, Shuang

    2012-01-01

    The objective of this study was to highlight the significance of microorganism growth on the production of biomacromolecules (BMM) in a membrane bioreactor (MBR). During the MBR operation, both polysaccharides and proteins in the sludge supernatant were found to increase steadily in exponential...

  20. High rate biological nutrient removal from high strength wastewater using anaerobic-circulating fluidized bed bioreactor (A-CFBBR).

    Science.gov (United States)

    Andalib, Mehran; Nakhla, George; Zhu, Jesse

    2012-08-01

    Biological nutrient removal (BNR) from high strength wastewater was investigated using a newly developed integrated anaerobic fluidized bed (AF) with circulating fluidized bed bioreactor henceforth called A-CFBBR. The A-CFBBR showed 99.7%COD removal, 84% nitrogen removal, with a very low sludge yield of 0.017 g VSS/g COD while treating a synthetic wastewater containing 10,700 mg COD/L and 250 mg NH(3)-N/L over a period of 6 months. The system was operated at an organic loading rate (OLR) of 35 kg COD/m(3)(AF) d and nitrogen loading rate (NLR) of 1.1 kg N/m(3)(CFBBR) d at a hydraulic retention time (HRT) of less than 12 h in the A-CFBBR. Microbial communities analysis using DGGE confirmed the presence of both AOBs and NOBs in the riser and downer. Pseudomonas putida and Pseudomonas fluorescence were the dominant denitrifiers present in the downer. Methanogenic activity was accomplished by a microbial mixture of archaea and bacteria in the anaerobic column.

  1. CONTINUOUS PRODUCTION OF ETHANOL IN BED PACKED BIOREACTORS WITH IMMOBILIZED YEAST CELLS ON LIGNOCELLULOSIC WASTE

    National Research Council Canada - National Science Library

    LINA MARÍA AGUDELO ESCOBAR; URIEL SALAZAR ÁLVAREZ; MARIANA PEÑUELA

    2012-01-01

    .... In this work, we evaluated the continuous production of ethanol in bed packed reactors with yeast cells immobilized on lignocellulosic waste of wood shaving, cane bagasse, corn leave and corn cob...

  2. Membrane bioreactors fed with different COD/N ratio wastewater: impacts on microbial community, microbial products, and membrane fouling.

    Science.gov (United States)

    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.

  3. Enhanced atrazine removal using membrane bioreactor bioaugmented with genetically engineered microorganism

    Institute of Scientific and Technical Information of China (English)

    Chun LIU; Xia HUANG

    2008-01-01

    Bioaugmentation with genetically engineered microorganisms (GEMs) in a membrane bioreactor (MBR) for enhanced removal of recalcitrant pollutants was explored. An atrazine-degrading genetically engi-neered microorganism (GEM) with green fluorescent pro-tein was inoculated into an MBR and the effects of such a bioaugmentation strategy on atrazine removal were inves-tigated. The results show that atrazine removal was improved greatly in the bioaugmented MBR compared with a control system. After a start-up period of 6 days, average 94.7% of atrazine was removed in bioaugmented MBR when atrazine concentration of influent was 14.5 mg/L. The volu-metric removal rates increased linearly followed by atrazine loading increase and the maximum was 65.5 mg/(L·d). No negative effects were found on COD removal although carbon oxidation activity of bioaugmented sludge was lower than that of common sludge. After inoculation, adsorption to sludge flocs was favorable for GEM sur-vival. The GEM population size initially decreased shortly and then was kept constant at about 104-105 CFU/mL. Predation of micro-organisms played an important role in the decay of the GEM population. GEM leakage from MBR was less than 102 CFU/mL initially and was then undetectable. In contrast, in a conventionally activated sludge bioreactor (CAS), sludge bulking occurred possibly due to atrazine exposure, resulting in bioaugmentation failure and serious GEM leakage. So MBR was superior to CAS in atrazine bioaugmentation treatment using GEM.

  4. Improved Performance of Membrane Bioreactor by Sludge Ozonation for Reduction of Excess Sludge Production

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi-feng; HE Sheng-bing; CHEN Jian-meng

    2009-01-01

    To seek for an alternative solution for the treatment and disposal of excess activated sludge, a hybrid system of membrane bioreactor ( MBR) coupled with ozonation process (i.e., ozonation run) was set up to treat the domestic wastewater. A reference run without ozonation was also preformed as a control. The optimal ozone dose of solubilization in the ozonation run was firstly determined through the batch sludge ozonation tests. A 40-day continuous operation of the two parallel systems demonstrated that circulation of ozonized sludge as lysate did not impact the performance of MBR in terms of organic and ammonia removal. On the contrary, an improvement in TN removal (by 7.7%) and sludge reduction (by 54%) was observed in the ozonation-combined MBR, and it was furthermore illustrated by the calculation of the mass balance based on the COD and TN substances. In addition,ozonation did not deteriorate the sludge activities for the ozonation run, indicating that not much inert organic materials built up in the bioreactor. Decreased VSS/SS ratio and lower amount of filamentous bacteria after ozonation treatment on the other hand improved the sludge settleability, as lower and constant Sluge Volume Index (SVI) values were detected in the ozonation run.

  5. Lipid production with Trichosporon oleaginosus in a membrane bioreactor using microalgae hydrolysate.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Virus rejection with two model human enteric viruses in membrane bioreactor system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A membrane bioreactor (MBR) with gravity drain was tested for virus rejection with two coliphages, T4 and f2, which were used as surrogates for human enteric viruses. Virus rejection was investigated by PVDF and PP membrane modules, with the pore sizes of 0.22 and 0.1 μm, respectively. In tap water system, 2.1 lg rejection of coliphage T4 could be achieved by PVDF membrane compared with complete rejection by PP membrane, while for coliphage f2 with smaller diameter, 0.3―0.5 lg rejection of the influent virus was removed by the two membranes. In domestic wastewater system, cake layer and gel layer on the membrane surface changed the cut-off size of the membrane so that there was no significant difference between PP and PVDF for each coliphage. The removal ratios of coliphage T4 and f2 in the MBR were more than 5.5 and 3.0 lg, respectively. Compared with 5.5 lg removal for virus T4 in the MBR system, only 2.1 lg (96.8%―99.9%) removal rate was observed in the conventional activated sludge system with the influent virus concentration fluctuating from 1830 to 57000 PFU/mL. Only 0.8%―22% virus removal was the effect of adsorption to activated sludge, which showed a decreasing tendency with the retention time, while 75%―98% was the effect of virus inactivation by microbial activity. It indicated that the major mechanism of virus removal was not the transfer of viruses from the water phase to the sludge phase but inactivation in the biological treatment process.

  7. Virus rejection with two model human enteric viruses in membrane bioreactor system

    Institute of Scientific and Technical Information of China (English)

    ZHENG Xiang; LIU JunXin

    2007-01-01

    A membrane bioreactor (MBR) with gravity drain was tested for virus rejection with two coliphages, T4 and f2, which were used as surrogates for human enteric viruses. Virus rejection was investigated by PVDF and PP membrane modules, with the pore sizes of 0.22 and 0.1 μm, respectively. In tap water system, 2.1 lg rejection of coliphage T4 could be achieved by PVDF membrane compared with complete rejection by PP membrane, while for coliphage f2 with smaller diameter, 0.3-0.5 lg rejection of the influent virus was removed by the two membranes. In domestic wastewater system, cake layer and gel layer on the membrane surface changed the cut-off size of the membrane so that there was no significant difference between PP and PVDF for each coliphage. The removal ratios of coliphage T4 and f2 in the MBR were more than 5.5 and 3.0 lg, respectively. Compared with 5.5 lg removal for virus T4 in the MBR system, only 2.1 lg (96.8%-99.9%) removal rate was observed in the conventional activated sludge system with the influent virus concentration fluctuating from 1830 to 57000 PFU/mL. Only 0.8 %-22 % virus removal was the effect of adsorption to activated sludge, which showed a decreasing tendency with the retention time, while 75%-98% was the effect of virus inactivation by microbial activity. It indicated that the major mechanism of virus removal was not the transfer of viruses from the water phase to the sludge phase but inactivation in the biological treatment process.

  8. Impact of virus surface characteristics on removal mechanisms within membrane bioreactors.

    Science.gov (United States)

    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.

  9. A review of practical tools for rapid monitoring of membrane bioreactors.

    Science.gov (United States)

    Scholes, E; Verheyen, V; Brook-Carter, P

    2016-10-01

    The production of high quality effluent from membrane bioreactors (MBRs) arguably requires less supervision than conventional activated sludge (CAS) processes. Nevertheless, the use of membranes brings additional issues of activated sludge filterability, cake layer formation and membrane fouling. From a practical standpoint, process engineers and operators require simple tools which offer timely information about the biological health and filterability of the mixed liquor as well as risks of membrane fouling. To this end, a range of analytical tools and biological assays are critically reviewed from this perspective. This review recommends that Capillary Suction Time (CST) analysis along with Total Suspended and Volatile Solids (TSS/VSS) analysis is used daily. For broad characterisation, total carbon and nitrogen analysis offer significant advantages over the commonly used chemical and biological oxygen demand (COD/BOD) analyses. Of the technologies for determining the vitality of the microbial biomass the most robust and reproducible, are the second generation adenosine-5'-triphosphate (ATP) test kits. Extracellular polymer concentrations are best monitored by measurement of turbidity after centrifugation. Taken collectively these tools can be used routinely to ensure timely intervention and smoother operation of MBR systems.

  10. THE USE OF BIOREACTORS COUPLED WITH MEMBRANES FOR THE TREATMENT OF EFFLUENTS

    Directory of Open Access Journals (Sweden)

    Bergamasco R.

    1997-01-01

    Full Text Available The objectives of this paper are to verify the viability of operating a bioreactor coupled with a membrane, and to analyze the global mechanisms witch need to be considered in the bioreactional concept in the separation by membrane. In order to meet the proposed objectives, a culture with a synthetic substratum (ethanol was utilized. A mineral membrane with the following characteristics was used: a pore diameter of 0.2 m m, 19 channels of a 4 mm diameter, a width of 0.85 m, a filtering surface area of 0.2 m2, a pressure of 2 bar and a tangential velocity of 2 m/s. The experiments consisted of modifying the residence time of the substratum within the reactor. The following measurements were taken: chemical oxygen demand (COD, concentration of biomass and filtered flow. The results show a treated effluent of good quality, indicating that the time of hydraulic residence time influences the efficiency of the system and is influenced by the restriction of the filtered flow by a fast fouling of the membrane

  11. Removal of phosphorus from wastewaters using ferrous salts - a pilot scale membrane bioreactor study.

    Science.gov (United States)

    Wang, Yuan; Tng, K Han; Wu, Hao; Leslie, Greg; Waite, T David

    2014-06-15

    A pilot scale membrane bioreactor (3.7 m(3)/day capacity), configured for alternate point ferrous sulphate addition, was evaluated in a fourteen month trial to comply with an effluent discharge requirement of less than 0.15 mg-P/L at the 50(th) percentile and less than 0.30 mg-P/L at the 90th percentile. Ferrous sulphate was added at a molar ratio (Fe(II):PO4) of 2.99 in the filtration chamber for 85 days and 2.60 in the primary anoxic zone for 111 days. Addition of ferrous salts to the anoxic zone achieved a final effluent phosphorous concentration (mg-P/L) of ferrous salts in the filtration zone achieved ferrous salts were added to the membrane zone while the reactor behaved close to a completely mixed reactor when dosing to the primary anoxic zone, resulting in improved phosphorus removal. The addition of ferrous salt was also found to delay the onset of severe increase in trans-membrane pressure as a result of the removal of macro-molecules. However, detailed analysis of the form and concentration of iron species in the supernatant and permeate indicated that the presence of fine iron particles resulted in a higher fouling rate when Fe(II) was added to the membrane zone rather than the primary anoxic zone and could cause more severe irreversible fouling in long-term operation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Concept of Compound Retention Time for Organic Micro Pollutants in Anaerobic Membrane Bioreactor with Nanofiltration

    KAUST Repository

    Pan, Jiangjiang

    2011-12-01

    Organic micropollutants (OMPs) have received more and more attention in recent years due to their potential harmful effects on public health and aquatic ecosystems, and eliminating OMPs in wastewater treatment systems is an important solution to control OMPs wastage. An innovative hybrid process, anaerobic membrane bioreactor with nanofiltration (AnMBR-NF), in which enhanced OMPs removal is possible based on the concept of compound retention time (CRT) through coupling anaerobic biodegradation and NF rejection, is proposed and examined in terms of preliminary feasibility in this study. First, NF membrane screening through sludge water dead-end filtration tests demonstrated that KOCH NF200 (molecular weight cut-off (MWCO) 200 Da, acid/base stable) performed best in organic matter rejection. Then, selected OMPs (ketobrofen and naproxen) in MQ water and a biologically treated wastewater matrix were filtered through NF200 under constant-pressure dead-end mode, with and without stirring, and several methods (contact angle, scanning electronic microscopy, Zeta potential, Fourier transform infra-red spectroscopy) were used to characterize membranes. Results show selected OMPs in MQ could be rejected (about 40%) by a clean NF200 membrane. The main rejection mechanism was initial absorption by the membrane followed by size exclusion (electric charge interaction plays a less important role). The wastewater matrix could enhance the rejection significantly (up to 90%) because effluent organic matter (EfOM) enhanced size exclusion and electric charge interaction through blocking membrane pores and forming a gel layer as well as binding some OMPs through partitioning followed by retention by NF. Third, an anaerobic bioreactor was set up to evaluate the anaerobic biodegradability of selected OMPs. Results showed selected OMPs could be absorbed by sludge and reached equilibrium within one day, and then were consumed by anaerobic microorganism with a half life 9.4 days for

  13. Comparative assessment of a biofilter, a biotrickling filter and a hollow fiber membrane bioreactor for odor treatment in wastewater treatment plants.

    Science.gov (United States)

    Lebrero, Raquel; Gondim, Ana Celina; Pérez, Rebeca; García-Encina, Pedro A; Muñoz, Raúl

    2014-02-01

    A low abatement efficiency for the hydrophobic fraction of odorous emissions and a high footprint are often pointed out as the major drawbacks of conventional biotechnologies for odor treatment. In this work, two conventional biotechnologies (a compost-based biofilter, BF, and a biotrickling filter, BTF), and a hollow-fiber membrane bioreactor (HF-MBR) were comparatively evaluated in terms of odor abatement potential and pressure drop (ΔP) at empty bed residence times (EBRTs) ranging from 4 to 84 s, during the treatment of methyl-mercaptan, toluene, alpha-pinene and hexane at trace level concentrations (0.75-4.9 mg m(-3)). High removal efficiencies (RE > 90% regardless of the air pollutant) were recorded in the BF at EBRTs ≥ 8 s, although the high ΔP across the packed bed limited its cost-effective operation to EBRTs > 19 s. A complete methyl-mercaptan, toluene and alpha-pinene removal was recorded in the BTF at EBRTs ≥ 4 s and ΔP lower than 33 mmH2O (∼611 Pa mbed(-1)), whereas slightly lower REs were observed for hexane (∼88%). The HF-MBR completely removed methyl-mercaptan and toluene at all EBRTs tested, but exhibited an unstable alpha-pinene removal performance as a result of biomass accumulation and a low hexane abatement efficiency. Thus, a periodical membrane-cleaning procedure was required to ensure a steady abatement performance. Finally, a high bacterial diversity was observed in the three bioreactors in spite of the low carbon source spectrum present in the air emission.

  14. Membrane fouling in a submerged membrane bioreactor with focus on surface properties and interactions of cake sludge and bulk sludge.

    Science.gov (United States)

    Yu, Haiying; Lin, Hongjun; Zhang, Meijia; Hong, Huachang; He, Yiming; Wang, Fangyuan; Zhao, Leihong

    2014-10-01

    In this study, the fouling behaviors and surface properties of cake sludge and bulk sludge in a submerged membrane bioreactor (MBR) were investigated and compared. It was found that the specific filtration resistance (SFR) of cake sludge was about 5 times higher than that of bulk sludge. Two types of sludge possessed similar extracellular polymeric substances (EPS) content, particle size distribution (PSD) and zeta potential. However, their surface properties in terms of surface tensions were significantly different. Further analysis showed that cake sludge was more hydrophilic and had worse aggregation ability. Moreover, cake sludge surface possessed more hydrocarbon, less oxygen and nitrogen moieties than bulk sludge surface. It was suggested that, rather than EPS and PSD differences, the differences in the surface composition were the main cause of the great differences in SFR and adhesion ability between cake sludge and bulk sludge.

  15. Alcoholic fermentation of xylose by immobilized Pichia stipitis in a fixed-bed pulsed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Sanroman, A.; Chamy, R.; Nunez, M.J.; Lema, J.M. (Santiago de Compostela Univ. (Spain). Dept. of Chemical Engineering)

    1994-01-01

    To enhance the productivity of the fermentation of xylose by Pichia stipitis, it is important to use bioreactors that (a) allow a high concentration of yeast (this can be achieved by using immobilised yeasts), (b) reduce the diffusional limitations resulting from dead volume (due mainly to the supplied and produced gas), and (c) diminish the effect of inhibition by ethanol. The process of immobilising P. stipitis in [kappa]-carrageenan was amended through the subsequent treatment of the bioparticles with a hardening agent (Al[sup 3+]). The variables examined were the cellular mass/gel mass ratio, the concentration of the hardening solution, and the contact time between the bioparticles and the hardening agent. (author)

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

    KAUST Repository

    Harb, Moustapha

    2016-07-09

    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. Comparing and Contrasting Traditional Membrane Bioreactor Models with Novel Ones Based on Time Series Analysis

    Directory of Open Access Journals (Sweden)

    Parneet Paul

    2013-02-01

    Full Text Available The computer modelling and simulation of wastewater treatment plant and their specific technologies, such as membrane bioreactors (MBRs, are becoming increasingly useful to consultant engineers when designing, upgrading, retrofitting, operating and controlling these plant. This research uses traditional phenomenological mechanistic models based on MBR filtration and biochemical processes to measure the effectiveness of alternative and novel time series models based upon input–output system identification methods. Both model types are calibrated and validated using similar plant layouts and data sets derived for this purpose. Results prove that although both approaches have their advantages, they also have specific disadvantages as well. In conclusion, the MBR plant designer and/or operator who wishes to use good quality, calibrated models to gain a better understanding of their process, should carefully consider which model type is selected based upon on what their initial modelling objectives are. Each situation usually proves unique.

  18. Enhanced biological phosphorus removal and its modeling for the activated sludge and membrane bioreactor processes.

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. The role of EPS in fouling and foaming phenomena for a membrane bioreactor.

    Science.gov (United States)

    Cosenza, Alida; Di Bella, Gaetano; Mannina, Giorgio; Torregrossa, Michele

    2013-11-01

    In contraposition to conventional activated sludge processes, the foaming phenomenon in membrane bioreactor (MBR) is still in its infancy. On the other hand, although several studies have been carried out for better understanding the fouling phenomenon in MBR there are still some gaps in the up-to-date knowledge. The extracellular polymeric substances (EPSs) may have a primary role in fouling and foaming phenomena which in turn can be crucial for MBRs. The aim of this study is to detect a possible relationship that EPSs may have with fouling and foaming in an MBR for wastewater treatment. Foaming phenomenon is monitored by performing specific foam-tests: Foam Power, Scum Index, Foam Rating and filamentous abundance. Results show a high correlation between fouling vs EPS and foaming vs bound EPSs. A relationship between foaming and fouling was also found: in general, when foaming occurred the fouling rate decreases because the EPS bound remained trapped in the floating scum.

  20. On the reversibility of cake buildup and compression in a membrane bioreactor

    DEFF Research Database (Denmark)

    Jørgensen, Mads Koustrup; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-01-01

    Fouling in a membrane bioreactor was studied by describing the reversibility of fouling developing during short-term experiments. Data were fitted to a recently proposed model of the buildup and compression of fouling layers. Shear stepping experiments performed to characterize the efficiency...... on compressed cake layers is released, the cake swells back to a looser structure. Based on these observations, we discuss the validity of using the critical flux concept to study fouling irreversibility. Modeling data of short-term filtration tests shows that the presence of a critical flux for irreversible...... fouling depends on the relaxation time relative to the filtration time and pressure. Therefore, to observe a critical flux for irreversible fouling, the relaxation times applied in the stepping approach should be customized to be sufficient to remove all removable fouling. The model suggests...

  1. Study on performance of submerged membrane bioreactor in proteinaceous wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    Zhang Ying; Ren Nanqi; Liu Xiaolei; Chen Zhaobo

    2005-01-01

    The continuous flowing experiment using a submerged membrane bioreactor (SMBR) in proteinaceous wastewater treatment was studied. The removal rate of the chemical oxygen demand (COD) was over 96.0% and the biochemical oxygen demand (BOD) was above 98.1%,the average removal rate of the total nitrogen (TN) was 61.7%,the removal rate of NH3-N was as high as 99%,but the removal effect of the total phosphorus (TP) was instable. The analysis under the condition of our experiments came to the conclusion that backwashing, waterpower scouring, low-pressure operation and control of mixed liquor suspended solid (MLSS) could lighten the attenuation of filtration flux in SMBR.

  2. Microbial adaptation to biodegrade toxic organic micro-pollutants in membrane bioreactor using different sludge sources.

    Science.gov (United States)

    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.

  3. Biodegradation of trace pharmaceutical substances in wastewater by a membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    Longli BO; Taro URASE; Xiaochang WANG

    2009-01-01

    The biodegradation of selected pharmaceutical micropollutants, including two pharmaceuticals with argued biodegradation, was studied by a lab-scale membrane bioreactor. The reaction kinetics and affecting factors were also investigated in this paper. Clofibric acid (CA) with contradictive biodegradation reported was degraded almost completely at different hydraulic retention times (HRTs) after adaptation to microorganisms. The biodegradation of CA was disturbed at low pH operation,while the activity of microorganisms recovered again after pH adjustment to neutral condition. Ibuprofen (IBP)degraded under neutral and acidic conditions. Removals of IBP and CA were zero-order and first-order reactions under high and low initial concentrations, respectively. Carbamazepine and diclofenac were not degraded regardless of HRTs and pH.

  4. Automatic control systems for submerged membrane bioreactors: a state-of-the-art review.

    Science.gov (United States)

    Ferrero, Giuliana; Rodríguez-Roda, Ignasi; Comas, Joaquim

    2012-07-01

    Membrane bioreactor (MBR) technology has become relatively widespread as an advanced treatment for both industrial and municipal wastewater, especially in areas prone to water scarcity. Although operational cost is a key issue in MBRs, currently only a few crucial papers and inventions aimed to optimise and enhance MBR efficiency have been published. The present review summarises the available solutions in the area of automatic control systems and widely explores the advances in automation and control for MBRs. In this review of state of the art, different control systems are evaluated comparatively, distinguishing between control systems used for the filtration process and those used for the biological process of MBRs and describing the challenge faced by integrated control systems. The existing knowledge is classified according to the manipulated variables, the operational mode (open-loop or closed-loop) and the controlled variables used.

  5. Fate of copper in submerged membrane bioreactors treating synthetic municipal wastewater.

    Science.gov (United States)

    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.

  6. Submerged membrane bioreactor using fly ash filters: trials with distillery wastewater.

    Science.gov (United States)

    Gupta, R; Satyawali, Y; Batra, V S; Balakrishnan, M

    2008-01-01

    This work presents preliminary results for distillery wastewater treatment in a MBR equipped with filters prepared from waste fly ash. The system was fabricated locally and employed submerged membranes in the 2-8 microm pore-size range. Distillery wastewater, after anaerobic digestion, was used as the feed and the bioreactor was inoculated with sludge obtained from a local distillery unit. The MBR was operated for around 250 days. The wastewater quality was monitored in terms of COD (chemical oxygen demand), colour, phenol, and MLSS (mixed liquor suspended solids) concentration. An average COD and phenol removal of 36% and 60% respectively was obtained. The maximum suspended solids retention by the ash filter was as high as 98%. The results were encouraging and further trials are currently underway to improve the performance.

  7. Multiple antibiotic resistance genes distribution in ten large-scale membrane bioreactors for municipal wastewater treatment.

    Science.gov (United States)

    Sun, Yanmei; Shen, Yue-Xiao; Liang, Peng; Zhou, Jizhong; Yang, Yunfeng; Huang, Xia

    2016-12-01

    Wastewater treatment plants are thought to be potential reservoirs of antibiotic resistance genes. In this study, GeoChip was used for analyzing multiple antibiotic resistance genes, including four multidrug efflux system gene groups and three β-lactamase genes in ten large-scale membrane bioreactors (MBRs) for municipal wastewater treatment. Results revealed that the diversity of antibiotic genes varied a lot among MBRs, but about 40% common antibiotic resistance genes were existent. The average signal intensity of each antibiotic resistance group was similar among MBRs, nevertheless the total abundance of each group varied remarkably and the dominant resistance gene groups were different in individual MBR. The antibiotic resistance genes majorly derived from Proteobacteria and Actinobacteria. Further study indicated that TN, TP and COD of influent, temperature and conductivity of mixed liquor were significant (Pantibiotic resistance genes distribution in MBRs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Removal of trace organic chemicals and performance of a novel hybrid ultrafiltration-osmotic membrane bioreactor.

    Science.gov (United States)

    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.

  9. Enhancement of the flux for polypropylene hollow fiber membrane in a submerged membrane-bioreactor by surface modification

    Institute of Scientific and Technical Information of China (English)

    YU Hai-yin; LEI Hao; XU Zhi-kang

    2006-01-01

    To improve its limiting flux and antifouling characteristics in a submerged membrane-bioreactor (SMBR) for wastewater treatment, polypropylene hollow fiber microporous membrane (PPHFMM) was surface-modified by the plasma-induced immobilization of poly (N-vinyl-2-pyrrolidone) (PVP) and the plasma treatment with different gases respectively. Attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to characterize the structural and morphological changes on the membrane surface. Water contact angle was measured by the sessile drop method. It was found that the water contact angle was 128.8, 72.3, 62.7, 74.4, 79.1,86.3, and 71.3° for the nascent, PVP-immobilized, air,O2, Ar, CO2 and H2O plasma treated PPHFMM, respectively. The SMBR was operated at fixed transmembrane pressure to determine the limiting flux for the PPHFMM before and after surface modification.Results showed that the limiting flux appeared to be 103, 159, 117, 133, 136, 121 and 152 L/(m2·h) for the nascent, PVP-immobilized,air, O2, Ar, CO2 and H2O plasma treated PPHFMM, respectively. After continuous operation for about 50 h in the SMBR, the antifouling characteristics were improved to some extent.

  10. Microbial responses to membrane cleaning using sodium hypochlorite in membrane bioreactors: Cell integrity, key enzymes and intracellular reactive oxygen species.

    Science.gov (United States)

    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.

  11. Effect of cyclic aeration on fouling in submerged membrane bioreactor for wastewater treatment.

    Science.gov (United States)

    Wu, Jun; He, Chengda

    2012-07-01

    Due to the inefficiency of aeration measures in preventing fouling by soluble and colloidal particles. The effect of alternating high/low cyclic aeration mode on the membrane fouling in the submerged membrane bioreactor was studied by comparing to fouling in a constant aeration mode. Results indicated a higher overall fouling rate in the cyclic aeration mode than in the constant aeration. However, a higher percentage of reversible fouling was observed for the cyclic aeration mode. The membrane permeability can be more easily recovered from physical cleaning such as backwashing in the cyclic aeration mode. The activated sludge floc size distribution analysis revealed a floc destruction and re-flocculation processes caused by the alternating high/low aeration. The short high aeration period could prevent the destruction of strong strength bonds within activated sludge flocs. Therefore, less soluble and colloidal material was observed in the supernatant due to the preservation of the strong strength bonds. The weak strength bonds damaged in the high aeration period could be recovered in the re-flocculation process in the low aeration period. The floc destruction and re-flocculation processes were suggested to be the main reason for the low irreversible fouling in the cyclic aeration mode.

  12. Dynamics of the Fouling Layer Microbial Community in a Membrane Bioreactor.

    Directory of Open Access Journals (Sweden)

    Anja S Ziegler

    Full Text Available 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.

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

    Science.gov (United States)

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

    2014-01-01

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

  14. Energy Consumption in Terms of Shear Stress for Two Types of Membrane Bioreactors used for Municipal Wastewater Treatment Processes

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Rasmussen, Michael R.

    2012-01-01

    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...... 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. Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

    Science.gov (United States)

    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. Biohybrid Membrane Systems and Bioreactors as Tools for In Vitro Drug Testing.

    Science.gov (United States)

    Salerno, Simona; Bartolo, Loredana De

    2017-01-01

    In drug development, in vitro human model systems are absolutely essential prior to the clinical trials, considering the increasing number of chemical compounds in need of testing, and, keeping in mind that animals cannot predict all the adverse human health effects and reactions, due to the species-specific differences in metabolic pathways. The liver plays a central role in the clearance and biotransformation of chemicals and xenobiotics. In vitro liver model systems by using highly differentiated human cells could have a great impact in preclinical trials. Membrane biohybrid systems constituted of human hepatocytes and micro- and nano-structured membranes, represent valuable tools for studying drug metabolism and toxicity. Membranes act as an extracellular matrix for the adhesion of hepatocytes, and compartmentalise them in a well-defined physical and chemical microenvironment with high selectivity. Advanced 3-D tissue cultures are furthermore achieved by using membrane bioreactors (MBR), which ensure the continuous perfusion of cells protecting them from shear stress. MBRs with different configurations allow the culturing of cells at high density and under closely monitored high perfusion, similarly to the natural liver. These devices that promote the long-term maintenance and differentiation of primary human hepatocytes with preserved liver specific functions can be employed in drug testing for prolonged exposure to chemical compounds and for assessing repeated-dose toxicity. The use of primary human hepatocytes in MBRs is the only system providing a faster and more cost-effective method of analysis for the prediction of in vitro human drug metabolism and enzyme induction alternative and/or complementary to the animal experimentation. In this paper, in vitro models for studying drug metabolism and toxicity as advanced biohybrid membrane systems and MBRs will be reviewed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    ZOU Haiyan; XI Danli

    2007-01-01

    Adding iron salt or iron hydroxide to sludgemixed liquor in an aeration tank of a conventional activated sludge processes (bioferric process) can simultaneously improve the sludge's filterability and enhance the system's treatment capacity.In view of this,Fe(OH)3 was added to a submerged membrane bioreactor (SMBR) to enhance the removal efficiency and to mitigate membrane fouling.Bioferric process and SMBR were combined to create a novel process called Bioferric-SMBR.A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out.Bioferric-SMBR showed potential superiority,which could enhance removal efficiency,reduce membrane fouling and improve sludge characteristic.When volumetric loading rate was 25% higher than that of common SMBR,the removal efficiencies of BioferricSMBR on COD,dye,and NH4+-N were 1.0%,9.5%,and 5.2% higher than that of common SMBR,respectively.The trans-membrane pressure of Bioferric-SMBR was only 36% of that in common SMBR while its membrane flux was 25% higher than that of common SMBR.The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged.The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans.The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR,respectively.

  18. The application of nitric oxide to control biofouling of membrane bioreactors.

    Science.gov (United States)

    Luo, Jinxue; Zhang, Jinsong; Barnes, Robert J; Tan, Xiaohui; McDougald, Diane; Fane, Anthony G; Zhuang, Guoqiang; Kjelleberg, Staffan; Cohen, Yehuda; Rice, Scott A

    2015-05-01

    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.

  19. Load maximization of a liquid-solid circulating fluidized bed bioreactor for nitrogen removal from synthetic municipal wastewater.

    Science.gov (United States)

    Chowdhury, Nabin; Nakhla, George; Zhu, Jesse

    2008-03-01

    A novel liquid-solid circulating fluidized bed bioreactor (LSCFB) configured with anoxic and aerobic columns and lava rock as the biofilm carrier was used to treat synthetic municipal wastewater. Four different empty bed contact times (EBCTs) of 0.82, 0.65, 0.55, and 0.44 h were examined to optimize nutrient removal capability of the system. The LSCFB demonstrated tertiary effluent quality organic and nitrogen removal efficiencies. Effluent characteristics of the LSCFB were soluble biological oxygen demand (SBOD)10 mg l(-1) and total nitrogen (TN)<10 mg l(-1) at organic loading rate (OLR) of 5.3 kg m(-3)d(-1) and nitrogen loading rate of 0.54 kg Nm(-3)d(-1). Remarkably low yields of 0.14, 0.17, 0.19, and 0.21 g VSS g(-1)COD were observed at OLR of 2.6, 3.2, 4.1 and 5.3 kg COD m(-3)d(-1), where increment of biomass growth and detachment rate were also experienced with increasing OLR. However the system demonstrated only 30% phosphorus removal, and mass balances along the anoxic and aerobic columns showed biological phosphorus removal in the system. Organic mass balance showed that approximately 40% of the influent COD was utilized in the anoxic column and the remaining COD was oxidized in the aerobic column. The system is very efficient in nitrification-denitrification, with more than 90% nitrification of ammonium and overall nitrogen removal in the LSCFB was 70+/-11% even at an EBCT of 0.44 h.

  20. Simultaneous production of laccase and decolouration of the diazo dye Reactive Black 5 in a fixed-bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Enayatzamir, Kheirghadam [Department of Chemical Engineering, Rovira i Virgili University, Av. Paisos Catalans 26, 43007 Tarragona (Spain); Department of Soil Science Engineering, University of Tehran, Karaj (Iran, Islamic Republic of); Alikhani, Hossein A. [Department of Soil Science Engineering, University of Tehran, Karaj (Iran, Islamic Republic of); Rodriguez Couto, Susana [Department of Chemical Engineering, Rovira i Virgili University, Av. Paisos Catalans 26, 43007 Tarragona (Spain)], E-mail: susana.rodriguez@urv.cat

    2009-05-15

    In this paper the production of laccase and the decolouration of the recalcitrant diazo dye Reactive Black 5 (RB5) by the white-rot fungus Trametes pubescens immobilised on stainless steel sponges in a fixed-bed reactor were studied. Laccase production was increased by 10-fold in the presence of RB5 and reached a maximum value of 1025 U/l. Enhanced laccase production in the presence of RB5 in this fungus is an added advantage during biodegradation of RB5-containing effluents. The decolouration of RB5 was due to two processes: dye adsorption onto the fungal mycelium and dye degradation by the laccase enzymes produced by the fungus. RB5 decolouration was performed during four successive batches obtaining high decolouration percentages (74%, 43% and 52% in 24 h for the first, third and four batch, respectively) without addition of redox mediators. Also, the in vitro decolouration of RB5 by the concentrated culture extract, containing mainly laccase, produced in the above bioreactor was studied. The decolouration percentages obtained were considerably lower (around 20% in 24 h) than that attained with the whole culture.

  1. Butyric acid production from sugarcane bagasse hydrolysate by Clostridium tyrobutyricum immobilized in a fibrous-bed bioreactor.

    Science.gov (United States)

    Wei, Dong; Liu, Xiaoguang; Yang, Shang-Tian

    2013-02-01

    A fermentation process using Clostridium tyrobutyricum immobilized in a fibrous-bed bioreactor (FBB) was developed for butyric acid production from sugarcane bagasse (SCB) hydrolysate. SCB was first treated with dilute acid and then hydrolyzed with cellulases. The hydrolysate containing glucose and xylose was used as carbon source for the fermentation without detoxification. The bacterium was able to grow at a specific growth rate of ∼0.06 h(-1) in media containing 15-20% (w/v) SCB in serum bottles. In batch cultures in the FBB, both glucose and xylose in the SCB hydrolysate were simultaneously converted to butyrate with a high yield (0.45-0.54 g/gsugar) and productivity (0.48-0.60 g/Lh). A final butyrate concentration of 20.9 g/L was obtained in a fed-batch culture, with an overall productivity of 0.51 g/Lh and butyrate yield of 0.48 g/g sugar consumed. This work demonstrated the feasibility of using SCB as a low-cost feedstock to produce butyric acid.

  2. Efficient production of butyric acid from Jerusalem artichoke by immobilized Clostridium tyrobutyricum in a fibrous-bed bioreactor.

    Science.gov (United States)

    Huang, Jin; Cai, Jin; Wang, Jin; Zhu, Xiangcheng; Huang, Lei; Yang, Shang-Tian; Xu, Zhinan

    2011-02-01

    Butyric acid is an important specialty chemical with wide industrial applications. The feasible large-scale fermentation for the economical production of butyric acid requires low-cost substrate and efficient process. In the present study, butyric acid production by immobilized Clostridium tyrobutyricum was successfully performed in a fibrous-bed bioreactor using Jerusalem artichoke as the substrate. Repeated-batch fermentation was carried out to produce butyric acid with a high butyrate yield (0.44 g/g), high productivity (2.75 g/L/h) and a butyrate concentration of 27.5 g/L. Furthermore, fed-batch fermentation using sulfuric acid pretreated Jerusalem artichoke hydrolysate resulted in a high butyric acid concentration of 60.4 g/L, with the yield of 0.38 g/g and the selectivity of ∼ 85.1 (85.1g butyric acid/g acetic acid). Thus, the production of butyric acid from Jerusalem artichoke on a commercial scale could be achieved based on the system developed in this work.

  3. Influence of operational parameters on the fluid-side mass transfer resistance observed in a packed bed bioreactor.

    Science.gov (United States)

    Hussain, Amir; Kangwa, Martin; Abo-Elwafa, Ahmed Gad; Fernandez-Lahore, Marcelo

    2015-01-01

    The influence of mass transfer on productivity as well as the performance of packed bed bioreactor was determined by varying a number of parameters; flow rate, glucose concentration and polymers (chitosan). Saccharomyces cerevisiae cells were immobilized in chitosan and non-chitosan coated alginate beads to demonstrate the effect on external mass transfer by substrate consumption time, lag phase and ethanol production. The results indicate that coating has a significant effect on the lag phase duration, being 30-40 min higher than non-coated beads. After lag phase, no significant change was observed in both types of beads on consumption of glucose with the same flow rate. It was observed that by increasing flow rates; lag phase and glucose consumption time decreased. The reason is due to the reduction of external mass transfer as a result of increase in flow rate as glucose is easily transported to and from the beads surface by diffusion. It is observed that chitosan acts as barrier for transfer of substrate and products, in and out of beads, at initial time of fermentation as it shows longer lag phase for chitosan coated beads than non-coated. Glucose consumption at low flow rate was lower as compared to higher flow rates. The optimum combination of parameters consisting of higher flow rates 30-90 ml/min and between 10 and 20 g/l of glucose was found for maximum production of ethanol.

  4. Membrane biofilm communities in full-scale membrane bioreactors are not randomly assembled and consist of a core microbiome

    KAUST Repository

    Matar, Gerald K.

    2017-06-21

    Finding efficient biofouling control strategies requires a better understanding of the microbial ecology of membrane biofilm communities in membrane bioreactors (MBRs). Studies that characterized the membrane biofilm communities in lab-and pilot-scale MBRs are numerous, yet similar studies in full-scale MBRs are limited. Also, most of these studies have characterized the mature biofilm communities with very few studies addressing early biofilm communities. In this study, five full-scale MBRs located in Seattle (Washington, U.S.A.) were selected to address two questions concerning membrane biofilm communities (early and mature): (i) Is the assembly of biofilm communities (early and mature) the result of random immigration of species from the source community (i.e. activated sludge)? and (ii) Is there a core membrane biofilm community in full-scale MBRs? Membrane biofilm (early and mature) and activated sludge (AS) samples were collected from the five MBRs, and 16S rRNA gene sequencing was applied to investigate the bacterial communities of AS and membrane biofilms (early and mature). Alpha and beta diversity measures revealed clear differences in the bacterial community structure between the AS and biofilm (early and mature) samples in the five full-scale MBRs. These differences were mainly due to the presence of large number of unique but rare operational taxonomic units (∼13% of total reads in each MBR) in each sample. In contrast, a high percentage (∼87% of total reads in each MBR) of sequence reads was shared between AS and biofilm samples in each MBR, and these shared sequence reads mainly belong to the dominant taxa in these samples. Despite the large fraction of shared sequence reads between AS and biofilm samples, simulated biofilm communities from random sampling of the respective AS community revealed that biofilm communities differed significantly from the random assemblages (P < 0.001 for each MBR), indicating that the biofilm communities (early

  5. Characterization of Membrane Foulants in Full-scale and Lab-scale Membrane Bioreactors for Wastewater Treatment and Reuse

    KAUST Repository

    Matar, Gerald

    2015-12-01

    Membrane bioreactors (MBRs) offer promising solution for wastewater treatment and reuse to address the problem of water scarcity. Nevertheless, this technology is still facing challenges associated with membrane biofouling. This phenomenon has been mainly investigated in lab-scale MBRs with little or no insight on biofouling in full-scale MBR plants. Furthermore, the temporal dynamics of biofouling microbial communities and their extracellular polymeric substances (EPS) are less studied. Herein, a multidisciplinary approach was adopted to address the above knowledge gaps in lab- and full-scale MBRs. In the full-scale MBR study, 16S rRNA gene pyrosequencing with multivariate statistical analysis revealed that the early and mature biofilm communities from five full-scale MBRs differed significantly from the source community (i.e. activated sludge), and random immigration of species from the source community was unlikely to shape the community structure of biofilms. Also, a core biofouling community was shared between the five MBR plants sampled despite differences in their operating conditions. In the lab-scale MBR studies, temporal dynamics of microbial communities and their EPS products were monitored on different hydrophobic and hydrophilic membranes during 30 days. At the early stages of filtration (1 d), the same early colonizers belonging to the class Betaproteobacteria were identified on all the membranes. However, their relative abundance decreased on day 20 and 30, and sequence reads belonging to the phylum Firmicutes and Chlorobi became dominant on all the membranes on day 20 and 30. In addition, the intrinsic membrane characteristic did not select any specific EPS fractions at the initial stages of filtration and the same EPS foulants developed with time on the hydrophobic and hydrophilic membranes. Our results indicated that the membrane surface characteristics did not select for specific biofouling communities or EPS foulants, and the same early

  6. Energy Consumption in Terms of Shear Stress for Two Types of Membrane Bioreactors Used for Municipal Wastewater Treatment Processes

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Bérube, P.R.

    2011-01-01

    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...... that the CFD results for the HS MBR were accurate. A linear empirical correlation between the average shear stress and the blower power per unit of permeate was made. This relationship includes: the air flow rate, the geometrical dimensions of the MBR, the permeate flux and the membrane area and can be used...

  7. Performance of Submerged Membrane Bioreactor Combined with Powdered Activated Carbon Addition for the Treatment of an Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Tri Widjaja

    2010-02-01

    Full Text Available Membrane technology is one of the alternative solutions to overcome industrial wastewater treatment developed nowadays. The addition of PAC (Powdered Activated Carbon in the activated sludge using Submerged Membrane Adsorption Hybrid Bioreactor (SMAHBR is expected to increase the organic material removal. The purpose of this study was to determine the performance of submerged membrane bioreactor and activated carbon adsorption capacity of organic materials in wastewater. This study used SIER (Surabaya Industrial Estate Rungkut – Surabaya, Indonesia waste as activated sludge operated at Mixed Liquor Suspended Solid (MLSS concentrations of 8000 and 15000 mg/l, and Chemical Oxygen Demand (COD concentrations of 1500, 2500 mg/l, Sludge Retention Time (SRT of 10;20; and 30 days and activated carbon variables of 0%; 2.5%; 5%; 7.5%; 10%. The results showed that the fouling potential occurred at high MLSS where the COD removal occurred at PAC addition of 10% reaching 91.86%. High Soluble Microbial Product (SMP accumulation (± 10 mg/l occurred in short SRT and high MLSS concentration. PAC addition resulted in decreased microorganisms in the reactor and better effluent of SMAHBR, as a result, the performance of the submerged membrane bioreactor would be restored.

  8. Influence of solids retention time on continuous H{sub 2} production using membrane bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Yeol [Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies,16-2 Onogawa, Tsukuba, Ibaraki 305 8506 (Japan); Li, Yu-You [Department of Environmental Science, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980 8579 (Japan); Noike, Tatsuya [Advanced Research Institute for the Sciences and Humanities, Nihon University 12-5, Goban-cho, Chiyoda-ku, Tokyo 102 8251 (Japan)

    2010-01-15

    The influence of solids retention time (SRT) on continuous H{sub 2} production in a submerged membrane bioreactor (MBR) was investigated using mixed mesophilic microflora. The bioreactor was continuously operated at the four SRTs of 2, 4, 12.5 and 90 d on a glucose medium under the hydraulic retention time (HRT) of 9 h and the mesophilic condition of 35 C {+-} 0.5. Stable biogas production with H{sub 2} content of 50.8%-60% was achieved at SRTs ranging from 2 to 12.5 d. No methane gas was observed in monitoring the experimental conditions. The H{sub 2} production increased from 17.62 to 26.1 l-H{sub 2}/d when the SRT increased from 2 to 12.5 d, but decreased to 9.1 l-H{sub 2}/d at the 90 d SRT. The best H{sub 2} yield, 1.19 mol-H{sub 2}/mol-glucose, was observed at the SRT of 2 d and the highest H{sub 2} production rate, 5.8 l-H{sub 2}/l/d, was obtained at the SRT of 12.5 d. Stable H{sub 2} production was achieved by maintaining the SRT in the range of 2 - 12.5 d, regardless of the fermentative pathway related to higher lactate production. The decrease in H{sub 2} yield was observed at long SRTs due to the low volatile suspended solids/total suspended solids (VSS/TSS) as well as the high extracellular polymeric substances (EPS) concentrations. These results suggest that the SRT is the key factor enabling sustainable H{sub 2} fermentation in MBR, and that an SLR value of around 1.6 kg-DOC/kg-VSS/d might be the specific condition for achieving optimum H{sub 2} production. (author)

  9. Comparison of microbial communities of activated sludge and membrane biofilm in 10 full-scale membrane bioreactors.

    Science.gov (United States)

    Jo, Sung Jun; Kwon, Hyeokpil; Jeong, So-Yeon; Lee, Chung-Hak; Kim, Tae Gwan

    2016-09-15

    Operation of membrane bioreactors (MBRs) for wastewater treatment is hampered by the membrane biofouling resulting from microbial activities. However, the knowledge of the microbial ecology of both biofilm and activated sludge in MBRs has not been sufficient. In this study, we scrutinized microbial communities of biofilm and activated sludge from 10 full-scale MBR plants. Overall, Flavobacterium, Dechloromonas and Nitrospira were abundant in order of abundance in biofilm, whereas Dechloromonas, Flavobacterium and Haliscomenobacter in activated sludge. Community structure was analyzed in either biofilm or activated sludge. Among MBRs, as expected, not only diversity of microbial community but also its composition was different from one another (p  0.05). Effects of ten environmental factors on community change were investigated using Spearman correlation. MLSS, HRT, F/M ratio and SADm explained the variation of microbial composition in the biofilm, whereas only MLSS did in the activated sludge. Microbial networks were constructed with the 10 environmental factors. The network results revealed that there were different topological characteristics between the biofilm and activated sludge networks, in which each of the 4 factors had different associations with microbial nodes. These results indicated that the different microbial associations were responsible for the variation of community composition between the biofilm and activated sludge.

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

    Science.gov (United States)

    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.

  11. Effect of ferric and ferrous iron addition on phosphorus removal and fouling in submerged membrane bioreactors.

    Science.gov (United States)

    Zhang, Zhenghua; Wang, Yuan; Leslie, Greg L; Waite, T David

    2015-02-01

    The effect of continuously dosing membrane bioreactors (MBRs) with ferric chloride (Fe(III)) and ferrous sulphate (Fe(II)) on phosphorus (P) removal and membrane fouling is investigated here. Influent phosphorus concentrations of 10 mg/L were consistently reduced to effluent concentrations of less than 0.02 mg/L and 0.03-0.04 mg/L when an Fe(III)/P molar ratio of 4.0 and Fe/P molar ratio (for both Fe(II) and Fe(III)) of 2.0 were used, respectively. In comparison, effluent concentrations did not decrease below 1.35 mg/L in a control reactor to which iron was not added. The concentrations of supernatant organic compounds, particularly polysaccharides, were reduced significantly by iron addition. The sub-critical fouling time (tcrit) after which fouling becomes much more severe was substantially shorter with Fe(III) dosing (672 h) than with Fe(II) dosing (1200-1260 h) at Fe/P molar ratios of 2.0 while the control reactor (no iron dosing) exhibited a tcrit of 960 h. Not surprisingly, membrane fouling was substantially more severe at Fe/P ratios of 4. Fe(II) doses yielding Fe/P molar ratios of 2 or less with dosing to the aerobic chamber were found to be optimal in terms of P removal and fouling mitigation performance. In long term operation, however, the use of iron for maintaining appropriately low effluent P concentrations results in more severe irreversible fouling necessitating the application of an effective membrane cleaning regime.

  12. Treatment of Chinese traditional medicine wastewater in a submerged membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    REN Nan-qi; CHEN Zhao-bo; ZHANG Ying; HU Dong-xue

    2007-01-01

    A pilot scale test was conducted in a submerged membrane bioreactor SMBR with capacity of 10.0 m3/d for 120 days to treat high-strength Chinese traditional medicine wastewater. Performance of the SMBR was investigated with a sludge retention time ( TSR ) of 50 days, a hydraulic retention time ( THR ) of 8. 0 h, membrane flux of 8. 0 L/( m2 · h) and dissolved oxygen (DO) concentration of 2.0 - 3.0 mg/L, respectively. It was observed that the SMBR had high capacity of COD and suspended solid (SS) removal. The influent COD concentration was fluctuated between 1 000 and 5 000 mg/L, while the averaged effluent COD concentration was only 44.6 mg/L. The influent SS concentration was fluctuated between 1 000 and 1 600 mg/L, while little effluent SS was detected. It was found that the COD remove rate increased with mixed liquor suspended solids (MLSS) and organic loading rate (ROL). In order to obtain good-quality effluent, the operational conditions of the SMBR were suggested as follows: the temperature was controlled above 10 ℃, MLSS about 7000 mg/L, ROL under 24. 76 kg/( m3 · d) , low vacuum value and constant water flux.

  13. Immersed membrane bioreactor (IMBR) for treatment of combined domestic and dairy wastewater in an isolated farm.

    Science.gov (United States)

    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.

  14. Influence of solid retention time on sludge characteristics and effluent quality in immersed membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    CAO ZhanPing; ZHANG JingLi; ZHANG HongWe

    2008-01-01

    Here the effect of solid retention time (SRT) on the concentration of the mixed liquor suspend solid (MLSS), the sludge characteristics, the content of extra-cellular polymeric substances (EPS), the viscosity of mixed liquor and effluent quality in the immersed membrane bioreactor (IMBR) was investigated. The results indicate that the increase of the EPS content is the main reason for the increase of mixed liquor viscosity, the former is positively correlated with the latter (R2 = 0.9751). The size distribution profile of particles in the mixed liquor presents double-peak shape at SRT more than 30 days. The filtration resistance of membrane in IMBR is mainly caused by the tiny particles and the viscosity of the mixed liquor. In this study, the extension of SRT can hardly affect the removal efficiency of Chemical Oxygen Demand (COD) and NH+4-N, and when SRT is below 30 days, silt density index (SDI15) is less than 3, the effluent can be deeply treated by using reverse osmosis system (RO) or nano-filtration system (NF). The method of controlling SRT is put forward by analyzing the relationship between SRT and the minimum generation-time of dominant bacteria (at the maximum specific growth rate under the operation temperature).

  15. Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity.

    Science.gov (United States)

    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)).

  16. Considerations on the design and financial feasibility of full-scale membrane bioreactors for municipal applications.

    Science.gov (United States)

    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.

  17. Validation of computational non-Newtonian fluid model for membrane bioreactor.

    Science.gov (United States)

    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.

  18. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions.

    Science.gov (United States)

    Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario

    2014-02-28

    Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100-1100mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15mg/gh were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum YX/S of 0.5g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16g/m(2).

  19. Performance evaluation of an side-stream anaerobic membrane bioreactor: Synthetic and alcoholic beverage industry wastewater

    Directory of Open Access Journals (Sweden)

    Nurdan BÜYÜKKAMACI

    2016-06-01

    Full Text Available The treatment performance of a laboratory-scale anaerobic membrane bioreactor (AnMBR using high strength wastewater was evaluated. The AnMBR model system consisted of an up-flow anaerobic sludge blanket reactor (UASB and an ultrafiltration (UF membrane. Its performance was first examined using molasses based synthetic wastewater at different hydraulic retention times (1-3 days and organic loading rates (5-15 kg COD/m3.day. As a result of the experimental studies, maximum treatment efficiency with respect to COD reduction (95% was achieved at 7.5 kg COD/m3.day OLR (CODinfluent=15.000 mg/L, HRT=2 days applications. When OLR was increased to 15 kg COD/m3.day, system performance decreased sharply. Similarly, methane gas production decreased by increasing OLR. After then, feed was changed to real wastewater, which was alcoholic beverage industry effluent. At this study, maximum COD removal efficiency of the system and maximum methane gas production was 88% and 74%, respectively.

  20. Removal of typical endocrine disrupting chemicals by membrane bioreactor: in comparison with sequencing batch reactor.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 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.

  2. Periodic harvesting of embryonic stem cells from a hollow-fiber membrane based four-compartment bioreactor.

    Science.gov (United States)

    Knöspel, Fanny; Freyer, Nora; Stecklum, Maria; Gerlach, Jörg C; Zeilinger, Katrin

    2016-01-01

    Different types of stem cells have been investigated for applications in drug screening and toxicity testing. In order to provide sufficient numbers of cells for such in vitro applications a scale-up of stem cell culture is necessary. Bioreactors for dynamic three-dimensional (3D) culture of growing cells offer the option for culturing large amounts of stem cells at high densities in a closed system. We describe a method for periodic harvesting of pluripotent stem cells (PSC) during expansion in a perfused 3D hollow-fiber membrane bioreactor, using mouse embryonic stem cells (mESC) as a model cell line. A number of 100 × 10(6) mESC were seeded in bioreactors in the presence of mouse embryonic fibroblasts (MEF) as feeder cells. Over a cultivation interval of nine days cells were harvested by trypsin perfusion and mechanical agitation every second to third culture day. A mean of 380 × 10(6) mESC could be removed with every harvest. Subsequent to harvesting, cells continued growing in the bioreactor, as determined by increasing glucose consumption and lactate production. Immunocytochemical staining and mRNA expression analysis of markers for pluripotency and the three germ layers showed a similar expression of most markers in the harvested cells and in mESC control cultures. In conclusion, successful expansion and harvesting of viable mESC from bioreactor cultures with preservation of sterility was shown. The present study is the first one showing the feasibility of periodic harvesting of adherent cells from a continuously perfused four-compartment bioreactor including further cultivation of remaining cells. © 2015 American Institute of Chemical Engineers.

  3. Evaluation of the Hanford 200 West Groundwater Treatment System: Fluidized Bed Bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Looney, Brian B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jackson, Dennis G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dickson, John O. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Eddy-Dilek, Carol A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-05-12

    A fluidized bed reactor (FBR) in the 200W water treatment facility at Hanford is removing nitrate from groundwater as part of the overall pump-treat-reinject process. Control of the FBR bed solids has proven challenging, impacting equipment, increasing operations and maintenance (O&M), and limiting the throughput of the facility. In response to the operational challenges, the Department of Energy Richland Office (DOE-RL) commissioned a technical assistance team to facilitate a system engineering evaluation and provide focused support recommendations to the Hanford Team. The DOE Environmental Management (EM) technical assistance process is structured to identify and triage technologies and strategies that address the target problem(s). The process encourages brainstorming and dialog and allows rapid identification and prioritization of possible options. Recognizing that continuous operation of a large-scale FBR is complex, requiring careful attention to system monitoring data and changing conditions, the technical assistance process focused on explicit identification of the available control parameters (“knobs”), how these parameters interact and impact the FBR system, and how these can be adjusted under different scenarios to achieve operational goals. The technical assistance triage process was performed in collaboration with the Hanford team.

  4. Mathematical modeling of continuous ethanol fermentation in a membrane bioreactor by pervaporation compared to conventional system: Genetic algorithm.

    Science.gov (United States)

    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.

  5. A Solution of the Convective-Diffusion Equation for Solute Mass Transfer inside a Capillary Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    B. Godongwana

    2010-01-01

    Full Text Available This paper presents an analytical model of substrate mass transfer through the lumen of a membrane bioreactor. The model is a solution of the convective-diffusion equation in two dimensions using a regular perturbation technique. The analysis accounts for radial-convective flow as well as axial diffusion of the substrate specie. The model is applicable to the different modes of operation of membrane bioreactor (MBR systems (e.g., dead-end, open-shell, or closed-shell mode, as well as the vertical or horizontal orientation. The first-order limit of the Michaelis-Menten equation for substrate consumption was used to test the developed model against available analytical results. The results obtained from the application of this model, along with a biofilm growth kinetic model, will be useful in the derivation of an efficiency expression for enzyme production in an MBR.

  6. Membrane bio-reactor - Research, pilot installation and measurement campaign; Membranbioreaktor (MBR) - Forschung, Pilotanlage und Messkampagne - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hersener, J.-L. [Ingenieurbuero Hersener, Wiesendangen (Switzerland); Meier, U. [Meritec GmbH, Guntershausen (Switzerland)

    2007-07-01

    This report for the Swiss Federal Office of Energy (SFOE), takes a look at a project involving a fermenter installation in Eastern Switzerland. Research work is noted, the pilot installation is described and the results of a measurement campaign are presented and commented on. The plant is able to handle about 20,000-25,000 tonnes of slurry and organic waste. The plant is built as a membrane bio-reactor and allows the separation of the digested biomass into fractions of solid and liquid fertilisers and useful water. Furthermore, a part of the separated and digested liquid is returned to the fermenter in order to improve the digestion process. For the production of electricity a 1.1 MW generator is installed. The adaptations made during the measurement period are noted and commented on. According to the authors, the results - although difficult to interpret - show that the concept of a membrane bio-reactor can work successfully.

  7. Numerical simulation of bubble induced shear in membrane bioreactors: effects of mixed liquor rheology and membrane configuration.

    Science.gov (United States)

    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

  8. Dependence of Shear and Concentration on Fouling in a Membrane Bioreactor with Rotating Membrane Discs

    DEFF Research Database (Denmark)

    Jørgensen, Mads Koustrup; Pedersen, Malene Thostrup; Christensen, Morten Lykkegaard

    2014-01-01

    of shear stress and sludge concentration on the limiting flux. The model was developed by calculating the shear rate at laminar flow regime at different rotation speeds and radii on the membrane. Furthermore, through the shear rate and shear stress, the non-Newtonian behavior of MBR sludge was addressed...

  9. Role of extracellular polymeric substances (EPSs) in membrane fouling of membrane bioreactor coupled with worm reactor.

    Science.gov (United States)

    Tian, Yu; Li, Zhipeng; Chen, Lin; Lu, Yaobin

    2012-11-01

    This study focused on the effect of worm reactor on the fouling behaviors of extracellular polymeric substances (EPSs) in the MBR coupled with Static Sequencing Batch Worm Reactor (SSBWR-MBR). The filtration tests showed that the C-EPS (EPS in Control-MBR) and S-EPS (EPS in SSBWR-MBR) resulted in 76% and 67% of flux decrement, respectively. On both fouling layers, the preferential accumulation was protein, but the adsorption efficiency for protein in C-EPS was 20% higher than that in S-EPS. In comparison with the membrane fouled by C-EPS, the bio-volume of protein on the membrane fouled by S-EPS reduced 33%, and the protein porosity increased 20%. Meanwhile, the S-EPS approaching the membrane had to overcome×2.4 stronger repulsive interaction energy than C-EPS, and the membrane fouled by S-EPS exhibited relatively smoother compared to that fouled by C-EPS. As a result, the fouling potential of S-EPS was lower than that of C-EPS. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. The environmental footprint of a membrane bioreactor treatment process through Life Cycle Analysis.

    Science.gov (United States)

    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.

  11. Assessment of energy-saving strategies and operational costs in full-scale membrane bioreactors.

    Science.gov (United States)

    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.

  12. Transport in a grooved perfusion flat-bed bioreactor for cell therapy applications.

    Science.gov (United States)

    Horner, M; Miller, W M; Ottino, J M; Papoutsakis, E T

    1998-01-01

    This study considers the transport of oxygen (a growth-associated solute) and lactate (a metabolic byproduct) in a flat-bed perfusion chamber modified to retain cells through the addition of grooves, perpendicular to the direction of flow, at the chamber bottom. The chamber has been successfully applied to hematopoietic cell culture and may be useful for other basic and applied biomedical applications. The objective of this study is to characterize the culture environment in terms of solute transport under various operational conditions. This will allow one to improve the design and operating strategy of the perfusion system for maximizing cell numbers. The system is numerically simulated using the finite element package FIDAP. The reaction kinetics describing oxygen uptake by cells are simplified to zero order to give an upper bound for the oxygen consumption. A flat-bed chamber without grooves is considered here as a benchmark. We show that the growth environment is not oxygen limited (local oxygen concentration above 10 microM) for a variety of flow rates and culture conditions (qO2 = 0.1 micromol/(10(6) cells h)). With a medium flow rate of 2.5 mL/min through the reactor, the model predicts that the 29-cm2 reactor can support at least 33.4 x 10(6) total cells when the inlet medium is in equilibrium with high (20%) oxygen concentration. The culture becomes oxygen limited however for the same flow rate for low (5%) oxygen concentration and can only support 7.2 x 10(6) total cells. Comparison of grooved vs nongrooved chambers reveals that the presence of grooves only affects solute transport on a local scale. This result is attributed to the small size (200 microgram) of the cavities relative to the chamber dimensions. The comparison also yields an empirical relation that allows for rapid estimation of oxygen and lactate concentrations in the grooves using only the numerical simulation of the simpler nongrooved chamber. Finally, our investigation shows that, while

  13. Operational parameters and their influence on particle-side mass transfer resistance in a packed bed bioreactor.

    Science.gov (United States)

    Hussain, Amir; Kangwa, Martin; Yumnam, Nivedita; Fernandez-Lahore, Marcelo

    2015-12-01

    The influence of internal mass transfer on productivity as well as the performance of packed bed bioreactor was determined by varying a number of parameters; chitosan coating, flow rate, glucose concentration and particle size. Saccharomyces cerevisiae cells were immobilized in chitosan and non-chitosan coated alginate beads to demonstrate the effect on particle side mass transfer on substrate consumption time, lag phase and ethanol production. The results indicate that chitosan coating, beads size, glucose concentration and flow rate have a significant effect on lag phase duration. The duration of lag phase for different size of beads (0.8, 2 and 4 mm) decreases by increasing flow rate and by decreasing the size of beads. Moreover, longer lag phase were found at higher glucose medium concentration and also with chitosan coated beads. It was observed that by increasing flow rates; lag phase and glucose consumption time decreased. The reason is due to the reduction of external (fluid side) mass transfer as a result of increase in flow rate as glucose is easily transported to the surface of the beads. Varying the size of beads is an additional factor: as it reduces the internal (particle side) mass transfer by reducing the size of beads. The reason behind this is the distance for reactants to reach active site of catalyst (cells) and the thickness of fluid created layer around alginate beads is reduced. The optimum combination of parameters consisting of smaller beads size (0.8 mm), higher flow rate of 90 ml/min and glucose concentration of 10 g/l were found to be the maximum condition for ethanol production.

  14. Semi-permeable membrane retention of synovial fluid lubricants hyaluronan and proteoglycan 4 for a biomimetic bioreactor.

    Science.gov (United States)

    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

  15. Irreversible fouling of membrane bioreactors due to formation of a non-biofilm gel-like layer

    DEFF Research Database (Denmark)

    Poorasgari, Eskandar; Larsen, Poul; Zheng, Xing

    2013-01-01

    Extra-cellular polymeric substances (EPS), known to contribute to fouling in membrane bio-reactors (MBR)s, are generally divided into bound and free EPS. The free EPS are able to form a gel-like layer on the membrane active surface. The mechanisms involved in formation of such layer and its effects...... with the amount of the humic-like substances retained during filtration as predicted by gel growth theory. A low pressure backwash could re-establish the water flux only up to 70%....

  16. A vibrating membrane bioreactor operated at supra- and sub-critical flux: Influence of extracellular polymeric substances from yeast cells

    DEFF Research Database (Denmark)

    Beier, Søren Prip; Jonsson, Gunnar Eigil

    2007-01-01

    A vibrating membrane bioreactor, in which the fouling problems are reduced by vibrating a hollow fiber membrane module, has been tested in constant flux microfiltration above (supra-critical) and below (sub-critical) an experimentally determined critical flux. Suspensions of bakers yeast cells were...... chosen as filtration medium (dry weight 4 g/l). The influence of extracellular polymeric substances (EPS) from the yeast cells is evaluated by UV absorbance measurements of the bulk supernatant during filtration. The critical flux seems to be an interval or a relative value rather than an absolute value...

  17. Heat transfer in a membrane assisted fluidised bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, S.A.R.K.; Volkers, S.; Sint Annaland, van M.; Kuipers, J.A.M.

    2004-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidised bed was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged in a staggered formation with the membrane tu

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

    Science.gov (United States)

    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.

  19. A Finite-Difference Solution of Solute Transport through a Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    B. Godongwana

    2015-01-01

    Full Text Available The current paper presents a theoretical analysis of the transport of solutes through a fixed-film membrane bioreactor (MBR, immobilised with an active biocatalyst. The dimensionless convection-diffusion equation with variable coefficients was solved analytically and numerically for concentration profiles of the solutes through the MBR. The analytical solution makes use of regular perturbation and accounts for radial convective flow as well as axial diffusion of the substrate species. The Michaelis-Menten (or Monod rate equation was assumed for the sink term, and the perturbation was extended up to second-order. In the analytical solution only the first-order limit of the Michaelis-Menten equation was considered; hence the linearized equation was solved. In the numerical solution, however, this restriction was lifted. The solution of the nonlinear, elliptic, partial differential equation was based on an implicit finite-difference method (FDM. An upwind scheme was employed for numerical stability. The resulting algebraic equations were solved simultaneously using the multivariate Newton-Raphson iteration method. The solution allows for the evaluation of the effect on the concentration profiles of (i the radial and axial convective velocity, (ii the convective mass transfer rates, (iii the reaction rates, (iv the fraction retentate, and (v the aspect ratio.

  20. Analysis of microbial community composition in a lab-scale membrane distillation bioreactor.

    Science.gov (United States)

    Zhang, Q; Shuwen, G; Zhang, J; Fane, A G; Kjelleberg, S; Rice, S A; McDougald, D

    2015-04-01

    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. 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. 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. This study provides an understanding of microbial community diversity in an MDBR, which is fundamental to the optimization of reactor performance. © 2015 The Authors published by John Wiley & Sons Ltd on behalf of Society for Applied Microbiology.

  1. Laboratory study of nitrification, denitrification and anammox processes in membrane bioreactors considering periodic aeration.

    Science.gov (United States)

    Abbassi, Rouzbeh; Yadav, Asheesh Kumar; Huang, Shan; Jaffé, Peter R

    2014-09-01

    The possibility of using membrane bioreactors (MBRs) in simultaneous nitrification-anammox-denitrification (SNAD) by considering periodic aeration cycles was investigated. Two separate reactors were operated to investigate the effect of different anammox biomass in the presence of nitrifying and denitrifying biomass on the final nitrogen removal efficiency. The results illustrated that the reactor with higher anammox biomass was more robust to oxygen cycling. Around 98% Total Nitrogen (TN) and 83% Total Organic Carbon (TOC) removal efficiencies were observed by applying one hour aeration over a four-hour cycle. Decreasing the aeration time to 30, 15, and 2 min during a four-hour cycle affected the final TN removal efficiencies. However, the effect of decreasing aeration on the TN removal efficiencies in the reactor with higher anammox biomass was much lower compared to the regular reactor. The nitrous oxide (N2O) emission was a function of aeration as well, and was lower in the reactor with higher anammox biomass. The results of q-PCR analysis confirmed the simultaneous co-existence of nitrifiers, anammox, and denitrifiers in both of the reactors. To simulate the TN removal in these reactors as a function of the aeration time, a new model, based on first order reaction kinetics for both denitrification and anammox was developed and yielded a good agreement with the experimental observations.

  2. [Effect of aeration intensity on the nitrogen and phosphorus removal performance of AOA membrane bioreactors].

    Science.gov (United States)

    Chen, Xiao-Yang; Xue, Zhi-Yong; Xiao, Jing-Ni; Zhang, Han-Min; Yang, Feng-Lin; Wang, Wei-Ping; Hong, Chun-Lai; Zhu, Feng-Xiang

    2011-10-01

    The ability of simultaneous phosphorus and nitrogen removal of sequencing batch membrane bioreactor run in anaerobic/oxic/ anoxic mode (AOA MBR) was examined under three aeration intensities [2.5, 3.75 and 5.0 m3 x (m2 x h)(-10]. The results showed that the averaged removals of COD were over 90% at different aeration intensities. And the higher aeration intensity was, the more ammonia nitrogen removal rate achieved. The removal rates of NH4(+) under the three aeration intensities were 84.7%, 90.6% and 93.8%, respectively. Total nitrogen removal rate increased with the increasing aeration intensity. But excessive aeration intensity reduced TN removal. The removal rates of TN under the three aeration intensities were 83.4%, 87.4% and 80.6%, respectively. Aeration intensity affected the denitrifying phosphorus ability of the AOA MBR. The ratio of denitrification phosphorus removal under the three aeration intensities were 20%, 30.2% and 26.7%, respectively.

  3. Study of Kinetic coefficients of a Membrane Bioreactor (MBR for municipal wastewater treatment

    Directory of Open Access Journals (Sweden)

    Ali Naghizadeh

    2013-08-01

    Full Text Available Background & Aims of the Study: In order to design membrane bioreactors (MBR properly, it is essential to comprehend the behavior of microorganisms in such wastewater treatment processes. Materials & Methods: In this study, a lab-scale MBR process was operated to determine the biokinetic coefficients of the MBR system under different MLSS concentrations of 6800, 7000, 7400, and 7800 mg/l and organic loading rates of 0.5 kg COD/m3/day. Results: The results of this study showed that the yield of microorganisms (Y, the endogenous decay coefficient (kd, the maximum specific growth rate (μmax and the saturation constant (Ks were in the range of 0.67 g VSS/g COD, 0.56 d−1, 1.86 d−1 and 6.65 mg COD/l, respectively. Conclusions: The kinetic coefficients in this study can be used to improve the operation and design the MBR system in full scale.

  4. Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works.

    Science.gov (United States)

    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.

  5. Enhanced sludge properties and distribution study of sludge components in electrically-enhanced membrane bioreactor.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  7. Hollow-fiber membrane bioreactor for the treatment of high-strength landfill leachate

    KAUST Repository

    Rizkallah, Marwan

    2013-07-15

    Performance assessment of membrane bioreactor (MBR) technology for the treatability of high-strength landfill leachate is relatively limited or lacking. This study examines the feasibility of treating high-strength landfill leachate using a hollow-fiber MBR. For this purpose, a laboratory-scale MBR was constructed and operated to treat leachate with a chemical oxygen demand (COD) of 9000-11,000 mg/l, a 5-day biochemical oxygen demand (BOD5) of 4000-6,000 mg/l, volatile suspended solids (VSS) of 300-500 mg/l, total nitrogen (TN) of 2000-6000 mg/l, and an ammonia-nitrogen (NH3-N) of 1800-4000 mg/l. VSS was used with the BOD and COD data to simulate the biological activity in the activated sludge. Removal efficiencies > 95-99% for BOD5, VSS, TN and NH3-N were attained. The coupled experimental and simulation results contribute in filling a gap in managing high-strength landfill leachate and providing guidelines for corresponding MBR application. © The Author(s) 2013.

  8. Rapid Startup and Loading of an Attached Growth, Simultaneous Nitrification/Denitrification Membrane Aerated Bioreactor

    Science.gov (United States)

    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.

  9. The ratio of metabolically active versus total Mycolata populations triggers foaming in a membrane bioreactor.

    Science.gov (United States)

    Maza-Márquez, P; Vílchez-Vargas, R; Boon, N; González-López, J; Martínez-Toledo, M V; Rodelas, B

    2016-04-01

    The abundance of total and metabolically active populations of Mycolata was evaluated in a full-scale membrane bioreactor (MBR) experiencing seasonal foaming, using quantitative PCR (qPCR) and retrotranscribed qPCR (RT-qPCR) targeting the 16S rRNA gene sequence. While the abundance of total Mycolata remained stable (10(10) copies of 16S rRNA genes/L activated sludge) throughout four different experimental phases, significant variations (up to one order of magnitude) were observed when the 16S rRNA was targeted. The highest ratios of metabolically active versus total Mycolata populations were observed in samples of two experimental phases when foaming was experienced in the MBR. Non-metric multidimensional scaling and BIO-ENV analyses demonstrated that this ratio was positively correlated to the concentrations of substrates in the influent water, F/M ratio, and pH, and negatively correlated to temperature and solids retention time. It the first time that the ratio of metabolically active versus total Mycolata is found to be a key parameter triggering foaming in the MBR; thus, we propose it as a candidate predictive tool.

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

    Science.gov (United States)

    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. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. COUPLING OF MEMBRANE BIOREACTOR AND OZONATION FOR REMOVAL OF ANTIBIOTICS FROM HOSPITAL WASTEWATER

    Directory of Open Access Journals (Sweden)

    Bui Xuan Thanh

    2016-02-01

    Full Text Available Antibiotic residues in the environment and their potential toxic effects have been considered as one of the emerging research area in the environmental field. Their continuous introduction in our environment may increase their negative impacts on human health.  In this study, the eliminations of antibiotic such as Norfloxacin (NOR, Ciprofloxacin (CIP, Ofloxacin (OFL and Sulfamethoxazole (SMZ in wastewater of hospital were processed by membrane bioreactor (MBR coupled with ozonation process. In particular, the MBR was applied for the antibiotic removals followed by ozonation process as a post-treatment stage to create an adequate integration to enhance removal efficiency. Achieved results after MBR treatment showed that the removal efficiency of NOR, CIP, OFL and SMZ were 90 ± 4.0% , 83 ± 13% , 81 ± 13 % and  39 ± 6%, respectivley. In addition, those antibiotic matters were continously removed by ozonation process with the removal efficiency of 87±9.0% , 83±1.0% , 81±2.3% and 66±2.3% for NOR, CIP, OFL and SMZ, respectively. In summary, antibiotics could be basically limited by the combination of MBR and ozonation before discharging in aquatic environment.

  12. Enhanced ethanol fermentation in a pervaporation membrane bioreactor with the convenient permeate vapor recovery.

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Filtration Characterization Method as Tool to Assess Membrane Bioreactor Sludge Filterability—The Delft Experience

    Directory of Open Access Journals (Sweden)

    Maria Lousada-Ferreira

    2014-04-01

    Full Text Available 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.

  14. Filtration characterization method as tool to assess membrane bioreactor sludge filterability-the delft experience.

    Science.gov (United States)

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

    Science.gov (United States)

    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.

    Science.gov (United States)

    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. Characterization of soluble microbial products and their fouling impacts in membrane bioreactors

    KAUST Repository

    Jiang, Tao

    2010-09-01

    Membrane bioreactor (MBR) fouling is not only influenced by the soluble microbial products (SMP) concentration but by their characteristics. Experiments of separate producing biomass associated products (BAP) and utilization associated products (UAP) allowed the separation of BAP and UAP effects from sludge water (SW). Thus, filtration of individual SMP components and further characterization becomes possible. Unstirred cell filtration was used to study fouling mechanisms and liquid chromatography-organic carbon detection (LC-OCD) and fluorescence excitation-emission matrix (EEM) were used to characterize the foulant. Generally, the SMP exhibiting characteristics of higher molecular weight, greater hydrophilicity and a more reduced state showed a higher retention percentage. However, the higher retention does not always yield higher fouling effects. The UAP filtration showed the highest specific cake resistance and pore blocking resistance attributed to their higher percentage of low molecular weight molecules, although their retention percentage was lower than the SW and BAP filtration. The UAP produced in the cell proliferation phase appeared to have the highest fouling potential. © 2010 American Chemical Society.

  18. Organic micro-pollutants’ removal via anaerobic membrane bioreactor with ultrafiltration and nanofiltration

    KAUST Repository

    Wei, Chun Hai

    2015-12-15

    The removal of 15 organic micro-pollutants (OMPs) in synthetic municipal wastewater was investigated in a laboratory-scale mesophilic anaerobic membrane bioreactor (AnMBR) using ultrafiltration and AnMBR followed by nanofiltration (NF), where powdered activated carbon (PAC) was added to enhance OMPs removal. No significant effects of OMPs spiking and NF connection on bulk organics removal and biogas production were observed. Amitriptyline, diphenhydramine, fluoxetine, sulfamethoxazole, TDCPP and trimethoprim showed readily biodegradable characteristics with consistent biological removal over 80%. Atrazine, carbamazepine, DEET, Dilantin, primidone and TCEP showed refractory characteristics with biological removal below 40%. Acetaminophen, atenolol and caffeine showed a prolonged adaption time of around 45 d, with initial biological removal below 40% and up to 50-80% after this period. Most readily biodegradable OMPs contained a strong electron donating group. Most refractory OMPs contained a strong electron withdrawing group or a halogen substitute. NF showed consistent high rejection of 80-92% with an average of 87% for all OMPs, which resulted in higher OMPs removal in AnMBR-NF than in AnMBR alone, especially for refractory OMPs. Limited sorption performance of PAC for OMPs removal was mainly due to low and batch dosage (100 mg/L) as well as the competitive sorption caused by bulk organics.

  19. Study on enhanced denitrification using particulate organic matter in membrane bioreactor by mechanism modeling.

    Science.gov (United States)

    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.

  20. Sludge Water Characteristics Under Different Separation Methods from a Membrane Bioreactor

    KAUST Repository

    Wei, Chunhai

    2013-11-22

    The concept of sludge water was proposed to integrate the relative terminologies and its characteristics under different separation methods from a membrane bioreactor (MBR) were investigated in this study. Based on chemical oxygen demand (COD) and three-dimensional fluorescence excitation-emission matrix (F-EEM), and compared with the control (gravitational sedimentation), some suspended particulate organics or biopolymer clusters (mainly proteins) were released from sludge flocs into the supernatant after centrifugation under low to middle centrifugal forces (10-4000 g) and then aggregated into a pellet under high centrifugal forces (10000-20000 g). Filtration (1.2 μm glass fiber filter) produced sludge water with a lower biopolymers concentration than the control (gravitational sedimentation followed by filtration) due to cake layer formation during filtration. As for centrifugation followed by filtration, low to middle centrifugal forces did not significantly affect sludge water characteristics but high centrifugal forces reduced the concentrations of some proteins in sludge water from advanced analytical protocols including F-EEM and liquid chromatography with on-line organic carbon detection (LC-OCD), demonstrating a low to middle centrifugal force suitable for MBR sludge water separation. From LC-OCD, the main fractions of sludge water were humic substances and building blocks, low molecular weight neutrals and biopolymers (mainly proteins rather than polysaccharides). Supplemental materials are available for this article. Go to the publisher\\'s online edition of Separation Science and Technology to view the supplemental file. © 2013 Copyright Taylor and Francis Group, LLC.

  1. Simultaneous activated carbon adsorption within a membrane bioreactor for an enhanced micropollutant removal.

    Science.gov (United States)

    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.

  2. A knowledge-based control system for air-scour optimisation in membrane bioreactors.

    Science.gov (United States)

    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.

  3. Inorganic nitrogen removal of toilet wastewater with an airlift external circulation membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    LI Gang; WU Lin-lin; DONG Chun-song; WU Guang-xia; FAN Yao-bo

    2007-01-01

    Removal of inorganic nitrogen (inorganic-N) removal of toilet wastewater with a pilot-scale airlift external circulation membrane bioreactor (AEC-MBR) was studied in this paper. The results showed that in the AEC-MBR, with a limited addition of alkalinity and the volumetric loading rates of inorganic-N at 0.19-0.40 kg inorganic-N/(m3·d), the desired nitrification and denitrification were achieved. Furthermore, the effects of pH and DO on inorganic-N removal were examined. Under the condition of MLSS at 1.56-2.35 g/L, BOD5/NH4+-N at 1.0, pH at 7.0-7.5 and DO at 1.0-2.0 mg/L, the removal efficiencies of NH4+-N and inorganic-N were 91.5% and 70.0% respectively in the AEC-MBR. The cost of addition of alkaline reagent was approximately 0.5-1.5 RMB Yuan/m3,and the energy consumption was approximately 0.72 kWh/m3 at the flux of 8 L/(m2·h).

  4. Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons.

    Science.gov (United States)

    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.

  5. Zero net growth in a membrane bioreactor with complete sludge retention.

    Science.gov (United States)

    Laera, G; Pollice, A; Saturno, D; Giordano, C; Lopez, A

    2005-12-01

    A bench-scale membrane bioreactor was operated with complete sludge retention in order to evaluate biological processes and biomass characteristics over the long term. The investigation was carried out by feeding a bench-scale plant with real sewage under constant volumetric loading rate (VLR = 1.2 gCOD L(react)(-1) h(-1)). Biological processes were monitored by measuring substrate removal efficiencies and biomass-related parameters. The latter included bacterial activity as determined through respirometric tests specifically aimed at investigating long term heterotrophic and nitrifying activity. After about 180 days under the imposed operating conditions, the system reached equilibrium conditions with constant VSS concentration of 16-18gL(-1), organic loading rate (OLR) below 0.1 gCOD gVSS(-1) d(-1) and specific respiration rates of 2-3 mgO2 gVSS(-1) h(-1). These conditions were maintained for more than 150 days, confirming that an equilibrium had been achieved between biomass growth, endogenous metabolism, and solubilization of inorganic materials.

  6. Physical characteristics of the sludge in a complete retention membrane bioreactor.

    Science.gov (United States)

    Pollice, A; Giordano, C; Laera, G; Saturno, D; Mininni, G

    2007-04-01

    Sludge physical characteristics play an important role in the operation of membrane bioreactors (MBR) due to their influence on filtration and their effects on handling of excess sludge. These systems are designed to maintain high solid concentrations, thus limiting sludge production and the related operational costs of the process. In this study, the sludge from a bench scale MBR operated for about 1 year with complete solid retention was investigated to assess its physical and rheological properties. Concentrations of mixed liquor suspended solids (MLSS) up to 24 gTSSL(-1) affected the diluted sludge volume index (DSVI), the capillary suction time (CST), the specific resistance to filtration (SRF) and the compressibility (s). The MBR sludge displayed similar dewatering properties of conventional waste activated sludge, suggesting that the upgrade of wastewater treatment plants with the MBR technology would not affect the behaviour of the dewatering equipment. The apparent viscosity was expressed as a function of the MLSS and the experimental data were interpreted by comparing different models. Ostwald model was chosen, and two equations for viscosity were proposed. The thixotropy of MBR sludge was also evaluated by measuring the reduced hysteresis area (rHa) and relating this parameter to the characteristics of the sludge. The evaluation of energy consumption for mixing evidenced that, under the tested conditions, the increase of solid concentration from 3 to 30 gTSSL(-1) resulted in a limited increase of energy requirements (25-30%).

  7. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent.

    Science.gov (United States)

    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.

  8. Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent

    Energy Technology Data Exchange (ETDEWEB)

    Satyawali, Yamini [TERI University, 10, Institutional Area, Vasant Kunj, New Delhi 110070 (India); Balakrishnan, Malini, E-mail: malinib@teri.res.in [TERI University, 10, Institutional Area, Vasant Kunj, New Delhi 110070 (India); Energy and Resources Institute (TERI), Darbari Seth Block, India Habitat Center, Lodhi Road, New Delhi 110003 (India)

    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 8 L reactor was equipped with a submerged 30 {mu}m nylon mesh filter with 0.05 m{sup 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{sup -3} d{sup -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.

  9. Modelling the biological performance of a side-stream membrane bioreactor using ASM1

    Institute of Scientific and Technical Information of China (English)

    TIAN Ke-jun; LIU Xin-ai; JIANG Tao; M.D. Kennedy; J.C. Schippers; P.A. Vanrolleghem

    2004-01-01

    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 modelling of a side-stream MBR system using Activated Sludge Model No.1(ASM1), and comparing the results with the modelling of traditional activated sludge processes. ASM1 parameters relevant for the long-term biological behaviour in MBR systems were calibrated(i.e. YH=0.72gCOD/gCOD, YA=0.25gCOD/gN, bH=0.25 d-1, bA=0.080 d-1 and fP=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. 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. YH, YA, bH, bA, (maxH and (maxA), and influent wastewater components(XI, Ss, Xs, SNH).

  10. ANALYSIS OF TRICKLE BED AND PACKED BUBBLE COLUMN BIOREACTORS FOR COMBINED CARBON OXIDATION AND NITRIFICATION

    Directory of Open Access Journals (Sweden)

    Iliuta I.

    2002-01-01

    Full Text Available Biological removal of nitrogen and carbon by combined nitrification-oxidation in gas-liquid trickle-bed reactors (TBRs and packed bubble columns (PBCs was analyzed theoretically using a transient two-dimensional model. The model describes TBR and PBC performances at steady state as well as their transient response to a pulse or step increase in inlet methanol and NH4+-nitrogen concentrations. The hydrodynamic parameters were determined from residence time distribution measurements, using an imperfect pulse method for time-domain analysis of nonideal pulse tracer response. A transient diffusion model of the tracer in the porous particle coupled with the piston-dispersion-exchange model was used to interpret the residence time distribution curves obtained. Gas-liquid mass transfer parameters were determined by a stationary method based on the least-squares fit of the calculated concentration profiles in gas phase to the experimental values. Analysis of steady-state performances showed that under like operating conditions, the TBR outperforms the PBC in terms of conversions. A pulse change in the inlet methanol or NH4+-nitrogen concentration causes a negligible transient change in the outlet methanol concentration and a negligible or high transient change in the outlet NH4+-nitrogen concentration. A step change in the inlet methanol concentration causes the negligible transient change in the methanol outlet concentration and a relatively important transient change in the NH4+-nitrogen outlet concentration. A step increase in the NH4+-nitrogen inlet concentration induces a drastic transient change in the NH4+-nitrogen outlet concentration but a negligible transient change in the methanol outlet concentration.

  11. Organic fouling behavior of superhydrophilic polyvinylidene fluoride (PVDF) ultrafiltration membranes functionalized with surface-tailored nanoparticles: Implications for organic fouling in membrane bioreactors

    KAUST Repository

    Liang, Shuai

    2014-08-01

    This study systematically investigates the organic fouling behavior of a superhydrophilic polyvinylidene fluoride (PVDF) ultrafiltration membrane functionalized via post-fabrication tethering of surface-tailored silica nanoparticles to poly(methacrylic acid)-grafted PVDF membrane surface. Sodium alginate (SA), Suwannee River natural organic matter (SRNOM), and bovine serum albumin (BSA) were used as model organic foulants to investigate the antifouling behavior of the superhydrophilic membrane with combined-fouling (mixture of foulants) and individual-fouling (single foulant) tests. A membrane bioreactor (MBR) plant supernatant was also used to verify the organic antifouling property of the superhydrophilic membrane under realistic conditions. Foulant size distributions and foulant-membrane interfacial forces were measured to interpret the observed membrane fouling behavior. Molecular weight cutoff measurements confirmed that membrane functionalization did not adversely affect the intrinsic membrane selectivity. Both filtration tests with the synthetic foulant-mixture solution (containing SA, SRNOM, and BSA) and MBR plant supernatant demonstrated the reliability and durability of the antifouling property of the superhydrophilic membrane. The conspicuous reduction in foulant-membrane interfacial forces for the functionalized membrane further verified the antifouling properties of the superhydrophilic membrane, suggesting great potential for applications in wastewater treatment. © 2014 Elsevier B.V.

  12. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario, E-mail: mariodiaz@uniovi.es

    2014-02-01

    Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h{sup −1} and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum Y{sub X/S} of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m{sup 2}.

  13. Model-based energy optimisation of a small-scale decentralised membrane bioreactor for urban reuse.

    Science.gov (United States)

    Verrecht, Bart; Maere, Thomas; Benedetti, Lorenzo; Nopens, Ingmar; Judd, Simon

    2010-07-01

    The energy consumption of a small-scale membrane bioreactor, treating high strength domestic wastewater for community level wastewater recycling, has been optimised using a dynamic model of the plant. ASM2d was chosen as biological process model to account for the presence of phosphate accumulating organisms. A tracer test was carried out to determine the hydraulic behaviour of the plant. To realistically simulate the aeration demand, a dedicated aeration model was used incorporating the dependency of the oxygen transfer on the mixed liquor concentration and allowing differentiation between coarse and fine bubble aeration, both typically present in MBRs. A steady state and dynamic calibration was performed, and the calibrated model was able to predict effluent nutrient concentrations and MLSS concentrations accurately. A scenario analysis (SCA) was carried out using the calibrated model to simulate the effect of varying SRT, recirculation ratio and DO set point on effluent quality, MLSS concentrations and aeration demand. Linking the model output with empirically derived correlations for energy consumption allowed an accurate prediction of the energy consumption. The SCA results showed that decreasing membrane aeration and SRT were most beneficial towards total energy consumption, while increasing the recirculation flow led to improved TN removal but at the same time also deterioration in TP removal. A validation of the model was performed by effectively applying better operational parameters to the plant. This resulted in a reduction in energy consumption by 23% without compromising effluent quality, as was accurately predicted by the model. This modelling approach thus allows the operating envelope to be reliably identified for meeting criteria based on energy demand and specific water quality determinants.

  14. Removal of Hospital Wastewater by Novel Nano-Filtration Membrane Bioreactor (NF-MBR

    Directory of Open Access Journals (Sweden)

    Farshad Golbabaei Kootenaei

    2013-01-01

    Full Text Available In this paper a pilot-scale membrane bioreactor (MBR equipped with nano-membranes treating the hospital wastewaters has been studied in order to evaluate the removal of nutrients. The main goal was to examine the feasibility of the NF-MBR used to treat hospital wastewater. Process efficiency was evaluated in terms of COD, NH3 N, NO3_N, NO3_N and PO4-P removal. The pilot plant located at the Babol Clinic Hospital,_Babol, Mazandaran, Iran. The performance of NF-MBR pilot for biological nutrient removal was evaluated during 62 days of operation. The NF-MBR resulting in respective HRT of 2.9 h. The influent COD, NH3_N and PO4-P averaged at 688, 11.8 and 3 mg/l respectively. The final treated effluent COD, NH3_N and PO4-P for the same period averaged 35, 1.69 and 0.89 mg/l respectively. The operating results of the pilot plant demonstrate that the NFMBR process is both effective and efficient in meeting the water discharge and reuse quality requirements at the hospital. The NF-MBR showed a high COD removal, stable and complete nitrification. The biological nutrient removal efficiencies were high from the start of operation with COD and NH 3 N removal efficiencies of 92 ± 4% and _88 ± 2, respectively. During the course of the experiment PO4-P removal efficiencies increased and finally PO4-P removal efficiency of 68% was achieved. Indicating that the NF-MBR effluent can be directly discharged into natural waters and it’s suitable for reuse.

  15. Hydrolysis of whey lactose by immobilized β-galactosidase in a bioreactor with a spirally wound membrane.

    Science.gov (United States)

    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%.

  16. 两种膜生物反应器工艺在养殖废水处理中的运行效果%Study on the operational effect of dynamic membrane bioreactor and membrane bioreactor for aquaculture wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    李伟博; 洪俊明

    2012-01-01

    Dynamic membrane bioreactor(DMBR) and membrane bioreactor(MBR) were used to treat aquaculture wastewater.The results showed that the CODMn removal rates by DMBR and MBR for treating aquaculture wastewater achieved above 95%.TN removal rates by DMBR and MBR were 71.4%,75.8%,when DO was 0—1 mg/L.When DO was 2—3 mg/L,TN removal rates by DMBR and MBR were 46.3% and 44.1% respectively.DMBR and MBR had high contaminant removal efficiencies.Trans-membrane pressure(TMP) of MBR was much higher than the TMP of DMBR.The operation time of MBR was 5 days when the DO was 0—1 mg/L.The effluent of DMBR depended on gravity,therefore the TMP was 3.97 kPa,and the operation time of DMBR could reach about 10 days.The results showed DMBR can effectively overcome some defects of MBR,such as high membrane cost and fouling.%采用动态膜生物反应器(dynamic membrane bioreactor,DMBR)和膜生物反应器(membrane bioreactor,MBR)两种处理工艺,研究在相同条件下对养殖废水的处理效果和运行条件。结果表明,不同溶解氧(dissolveoxygen,DO)条件下,DMBR和MBR对CODMn的去除率可达95%以上。DO为0~1 mg/L条件下,DMBR和MBR的总氮平均去除率分别达到71.4%、75.8%;在DO为2~3 mg/L条件下,DMBR和MBR的总氮平均去除率分别为46.3%、44.1%。DMBR和MBR两种工艺均能达到较好的污染物去除效果。MBR的过滤压差明显高于DMBR,低DO条件下(0~1 mg/L)的运行周期约为5天,DMBR采用重力流出水,运行周期约为10天,过滤压差最高时仅为3.97 kPa,在一定程度上克服MBR成本高、易污染等缺点。

  17. Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal in Membrane Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

    Directory of Open Access Journals (Sweden)

    Arij it Nath

    2017-01-01

    Full Text Available Hypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the fi rst step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. Aft er enzymatic digestion, low-molecular-mass peptides were purifi ed with cross-fl ow fl at sheet membrane (pore size 100 μm and then with tubular ceramic ultrafi ltration membrane (molecular mass cut-off 5 kDa. Eff ects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafi ltration membrane surface were examined and their positive eff ects were proven. For the fi ltration with ultrafi ltration membrane, transmembrane pressure of 3•105 Pa with 3-stage discontinuous diafi ltration was found optimal. The molecular mass distribution of purifi ed peptides using ultrafi ltration membrane was determined by a liquid chromatography–electrospray ionization quadrupole time-of-fl ight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency from the ultrafi ltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane fi ltration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purifi ed in the ultrafi ltration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus.

  18. A novel anaerobic electrochemical membrane bioreactor (AnEMBR) with conductive hollow-fiber membrane for treatment of low-organic strength solutions

    KAUST Repository

    Katuri, Krishna

    2014-11-04

    A new anaerobic treatment system that combined a microbial electrolysis cell (MEC) with membrane filtration using electrically conductive, porous, nickel-based hollow-fiber membranes (Ni-HFMs) was developed to treat low organic strength solution and recover energy in the form of biogas. This new system is called an anaerobic electrochemical membrane bioreactor (AnEMBR). The Ni-HFM served the dual function as the cathode for hydrogen evolution reaction (HER) and the membrane for filtration of the effluent. The AnEMBR system was operated for 70 days with synthetic acetate solution having a chemical oxygen demand (COD) of 320 mg/L. Removal of COD was >95% at all applied voltages tested. Up to 71% of the substrate energy was recovered at an applied voltage of 0.7 V as methane rich biogas (83% CH4; < 1% H2) due to biological conversion of the hydrogen evolved at the cathode to methane. A combination of factors (hydrogen bubble formation, low cathode potential and localized high pH at the cathode surface) contributed to reduced membrane fouling in the AnEMBR compared to the control reactor (open circuit voltage). The net energy required to operate the AnEMBR system at an applied voltage of 0.7 V was significantly less (0.27 kWh/m3) than that typically needed for wastewater treatment using aerobic membrane bioreactors (1-2 kWh/m3).

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

    Science.gov (United States)

    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.

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

    KAUST Repository

    Kim, Youngjin

    2016-02-09

    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 sulphate 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 sulphate to anaerobic microorganisms, MAP appears to be the most suitable draw solution for AnFDFOMBR.

  1. Nitrile bioconversion by Microbacterium imperiale CBS 498-74 resting cells in batch and ultrafiltration membrane bioreactors.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Significance of membrane bioreactor design on the biocatalytic performance of glucose oxidase and catalase: Free vs. immobilized enzyme systems

    DEFF Research Database (Denmark)

    Morthensen, Sofie Thage; Meyer, Anne S.; Jørgensen, Henning

    2017-01-01

    -induced enzyme immobilization in the porous support of an ultrafiltration membrane was used as strategy for entrapment of glucose oxidase and catalase. The biocatalytic productivity of the membrane reactor was found to be highly related to the oxygen availability, which in turn depended on the reactor......Membrane separation of xylose and glucose can be accomplished via oxidation of glucose to gluconic acid by enzymatic glucose oxidase catalysis. Oxygen for this reaction can be supplied via decomposition of hydrogen peroxide by enzymatic catalase catalysis. In order to maximize the biocatalytic...... productivity of glucose oxidase and catalase (gluconic acid yield per total amount of enzyme) the following system set-ups were compared: immobilization of glucose oxidase alone; co-immobilization of glucose oxidase and catalase; glucose oxidase and catalase free in the membrane bioreactor. Fouling...

  4. The effect of activated carbon addition on membrane bioreactor processes for wastewater treatment and reclamation - A critical review.

    Science.gov (United States)

    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.

  5. Integrating Microbial Electrochemical Technology with Forward Osmosis and Membrane Bioreactors: Low-Energy Wastewater Treatment, Energy Recovery and Water Reuse

    KAUST Repository

    Werner, Craig M.

    2014-06-01

    Wastewater treatment is energy intensive, with modern wastewater treatment processes consuming 0.6 kWh/m3 of water treated, half of which is required for aeration. Considering that wastewater contains approximately 2 kWh/m3 of energy and represents a reliable alternative water resource, capturing part of this energy and reclaiming the water would offset or even eliminate energy requirements for wastewater treatment and provide a means to augment traditional water supplies. Microbial electrochemical technology is a novel technology platform that uses bacteria capable of producing an electric current outside of the cell to recover energy from wastewater. These bacteria do not require oxygen to respire but instead use an insoluble electrode as their terminal electron acceptor. Two types of microbial electrochemical technologies were investigated in this dissertation: 1) a microbial fuel cell that produces electricity; and 2) a microbial electrolysis cell that produces hydrogen with the addition of external power. On their own, microbial electrochemical technologies do not achieve sufficiently high treatment levels. Innovative approaches that integrate microbial electrochemical technologies with emerging and established membrane-based treatment processes may improve the overall extent of wastewater treatment and reclaim treated water. Forward osmosis is an emerging low-energy membrane-based technology for seawater desalination. In forward osmosis water is transported across a semipermeable membrane driven by an osmotic gradient. The microbial osmotic fuel cell described in this dissertation integrates a microbial fuel cell with forward osmosis to achieve wastewater treatment, energy recovery and partial desalination. This system required no aeration and generated more power than conventional microbial fuel cells using ion exchange membranes by minimizing electrochemical losses. Membrane bioreactors incorporate semipermeable membranes within a biological wastewater

  6. Energy consumption in terms of shear stress for two types of membrane bioreactors used for municipal wastewater treatment processes

    Science.gov (United States)

    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.

  7. Desalination of mixed tannery effluent with membrane bioreactor and reverse osmosis treatment.

    Science.gov (United States)

    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.

  8. Graphene-coated hollow fiber membrane as the cathode in anaerobic electrochemical membrane bioreactors – Effect of configuration and applied voltage on performance and membrane fouling

    KAUST Repository

    Werner, Craig M.

    2015-12-22

    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 V 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 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.

  9. Reducing aeration energy consumption in a large-scale membrane bioreactor: Process simulation and engineering application.

    Science.gov (United States)

    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.

  10. [Analysis of Microbial Community in the Membrane Bio-Reactor (MBR) Rural Sewage Treatment System].

    Science.gov (United States)

    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

  11. Enantiomeric fraction determination of 2-arylpropionic acids in a package plant membrane bioreactor.

    Science.gov (United States)

    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.

  12. A novel membrane bioreactor enhanced by effective microorganisms for the treatment of domestic wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Jin Min; Wang Xin-Wei; Gong Tai-Shi; Gu Chang-Qin; Zhang Bin; Shen Zhi-Qiang; Li Jun-Wen [Institute of Environment and Health, Tianjin (China)

    2005-11-01

    The activated sludge membrane bioreactor (MBR) has been shown to have some advantages for the processing and reclamation of domestic wastewater. We hypothesized that certain microorganisms, chosen for their abilities to decompose the chemical components of raw sewage, would, when coupled with the MBR, significantly improve the stability and efficiency of this system. We selected environmental bacterial strains which oxidize ammonia and nitrites and produce protease, amylase, and cellulase for the development and testing of a novel biologically enhanced MBR (eMBR). We compared the eMBR with the activated sludge MBR. With the eMBR, the average values of effluent quality were: chemical oxygen demand (COD), 40 mg/l(average efficiency of removal 90.0%); and NH{sub 4}{sup +}-N, 0.66 mg/l(average efficiency of removal 99.4%). Effluent qualities met the standard and were stable during the entire 90 days of this study. For the activated sludge MBR, the COD removal rate was 91.7%, and the NH{sub 4}{sup +}-N removal (94.8%) was less than that of the eMBR. Start-up time for the eMBR was only 24-48 h, much shorter than the 7-8 days required to initiate function of the standard MBR. The biomass concentrations of total heterotrophic bacteria and autotrophic bacteria in the eMBR did not fluctuate significantly during the course of the study. Various kinds of microorganisms will establish an ecological balance in the reactor. Compared with the activated sludge MBR, the eMBR not only produced an excellent and stable quality of effluent but also resulted in a shorter time to start-up and significantly improved the efficiency of NH{sub 4}{sup +}-N removal. (orig.)

  13. Effect of Mass-Transport Limitations on the Performance of a Packed Bed Membrane Reactor for Partial Oxidations. Transport from the Membrane to the Packed Bed

    NARCIS (Netherlands)

    Sint Annaland, van M.; Kürten, U.; Kuipers, J.A.M.

    2007-01-01

    With a packed bed membrane reactor, the product yield can be significantly enhanced for partial oxidation systems, via distributive addition of oxygen to the reaction mixture along the axial coordinate of the reactor, provided that the reaction order in oxygen of the formation rate of the target pro

  14. Mathematical model analysis on the enhancement of aeration efficiency using ladder-type flat membrane module forms in the Submerged Membrane Bio-reactor (SMBR)

    Institute of Scientific and Technical Information of China (English)

    LI Bo; YE MaoSheng; YANG FengLin; MA Hui

    2009-01-01

    The cross-flow shearing action produced from the inferior aeration in the Submerged Membrane Bio-reactor (SMBR) Is an effective way to further improve anti-fouling effects of membrane modules.Based on the widely-applied vertical structure of flat membrane modules, improvements are made that ladder-type flat membrane structure is designed with a certain inclined angle θ so that the cross-flow velocity of bubble near the membrane surface can be held, and the intensity and times of elastic colli-sion between bubbles and membrane surface can be increased. This can improve scouring action ofmembrane surface on aeration and reduce energy consumption of strong aeration in SMBR. By de-ducing and improving the mathematics model of collision between bubble and vertical flat put forward by Vries, the relatively suitable Incline angle θ under certain aeration place and in certain size rang ofbubble can be obtained with the computer iterative calculation technology. Finally, for many groups of ladder-type flat membrane in parallel placement in the practical application of SMBR, some sugges-tions are offered: the interval distance of membrane modules is 8--15 mm, and aeration should be op-erated at 5--7 mm among membrane modules, and the optimal design angle of trapeziform membrane is 1.7°--2.5°.

  15. Fouling potential evaluation of soluble microbial products (SMP) with different membrane surfaces in a hybrid membrane bioreactor using worm reactor for sludge reduction.

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Preliminary Study on Airlift Membran—Bioreactor

    Institute of Scientific and Technical Information of China (English)

    XUNong; XINGWeihong; 等

    2002-01-01

    A new type of membrane bioreactor named “airlift membrane-bioreactor”is discussed.For municipal wastewater reclamation,the preliminary study on airlift membrane-bioreactor shows its good performance such as high flux and lower energy consumption.The airlift membrane-bioreactor is potentially applicable in bioengineering and environmental protection fields.

  17. Improvement of the antifouling characteristics in a bioreactor of polypropylene microporous membrane by the adsorption of Tween 20

    Institute of Scientific and Technical Information of China (English)

    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 scanning electron microscope (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.

  18. Assessing the removal of organic micro-pollutants from anaerobic membrane bioreactor effluent by fertilizer-drawn forward osmosis

    KAUST Repository

    Kim, Youngjin

    2017-03-23

    In this study, the behavior of organic micro-pollutants (OMPs) transport including membrane fouling was assessed in fertilizer-drawn forward osmosis (FDFO) during treatment of the anaerobic membrane bioreactor (AnMBR) effluent. The flux decline was negligible when the FO membrane was oriented with active layer facing feed solution (AL-FS) while severe flux decline was observed with active layer facing draw solution (AL-DS) with di-ammonium phosphate (DAP) fertilizer as DS due to struvite scaling inside the membrane support layer. DAP DS however exhibited the lowest OMPs forward flux or higher OMPs rejection rate compared to other two fertilizers (i.e., mono-ammonium phosphate (MAP) and KCl). MAP and KCl fertilizer DS had higher water fluxes that induced higher external concentration polarization (ECP) and enhanced OMPs flux through the FO membrane. Under the AL-DS mode of membrane orientation, OMPs transport was further increased with MAP and KCl as DS due to enhanced concentrative internal concentration polarization while with DAP the internal scaling enhanced mass transfer resistance thereby lowering OMPs flux. Physical or hydraulic cleaning could successfully recover water flux for FO membranes operated under the AL-FS mode but only partial flux recovery was observed for membranes operated under AL-DS mode because of internal scaling and fouling in the support layer. Osmotic backwashing could however significantly improve the cleaning efficiency.

  19. Membrane assisted fluidized bed reactors: Potentials and hurdles

    NARCIS (Netherlands)

    Deshmukh, S.A.R.K.; Heinrich, S.; Mörl, L.; van Sint Annaland, M.; Kuipers, J.A.M.

    2007-01-01

    Recent advances in the development of more stable membranes with increased permeance have significantly enhanced the possibilities for integrating membranes into catalytic reactors in order to achieve a major increase in reactor performance by process integration and process intensification. Several

  20. Dynamics of yeast immobilized-cell fluidized-bed bioreactors systems in ethanol fermentation from lactose-hydrolyzed whey and whey permeate.

    Science.gov (United States)

    Gabardo, Sabrina; Pereira, Gabriela Feix; Klein, Manuela P; Rech, Rosane; Hertz, Plinho F; Ayub, Marco Antônio Záchia

    2016-01-01

    We studied the dynamics of ethanol production on lactose-hydrolyzed whey (LHW) and lactose-hydrolyzed whey permeate (LHWP) in batch fluidized-bed bioreactors using single and co-cultures of immobilized cells of industrial strains of Saccharomyces cerevisiae and non-industrial strains of Kluyveromyces marxianus. Although the co-culture of S. cerevisiae CAT-1 and K. marxianus CCT 4086 produced two- to fourfold the ethanol productivity of single cultures of S. cerevisiae, the single cultures of the K. marxianus CCT 4086 produced the best results in both media (Y EtOH/S = 0.47-0.49 g g(-1) and Q P = 1.39-1.68 g L(-1) h(-1), in LHW and LHWP, respectively). Ethanol production on concentrated LHWP (180 g L(-1)) reached 79.1 g L(-1), with yields of 0.46 g g(-1) for K. marxianus CCT 4086 cultures. Repeated batches of fluidized-bed bioreactor on concentrated LHWP led to increased ethanol productivity, reaching 2.8 g L(-1) h(-1).

  1. Enhancing the Bioconversion of Winery and Olive Mill Waste Mixtures into Lignocellulolytic Enzymes and Animal Feed by Aspergillus uvarum Using a Packed-Bed Bioreactor.

    Science.gov (United States)

    Salgado, José Manuel; Abrunhosa, Luís; Venâncio, Armando; Domínguez, José Manuel; Belo, Isabel

    2015-10-28

    Wineries and olive oil industries are dominant agro-industrial activities in southern European regions. Olive pomace, exhausted grape marc, and vine shoot trimmings are lignocellulosic residues generated by these industries, which could be valued biotechnologically. In the present work these residues were used as substrate to produce cellulases and xylanases through solid-state fermentation using Aspergillus uvarum MUM 08.01. For that, two factorial designs (3(2)) were first planned to optimize substrate composition, temperature, and initial moisture level. Subsequently, the kinectics of cellulolytic enzyme production, fungal growth, and fermented solid were characterized. Finally, the process was performed in a packed-bed bioreactor. The results showed that cellulase activity improved with the optimization processes, reaching 33.56 U/g, and with the packed-bed bioreactor aeration of 0.2 L/min, reaching 38.51 U/g. The composition of fermented solids indicated their potential use for animal feed because cellulose, hemicellulose, lignin, and phenolic compounds were partially degraded 28.08, 10.78, 13.3, and 28.32%, respectively, crude protein was increased from 8.47 to 17.08%, and the mineral contents meet the requirements of main livestock.

  2. 生物流化床处理废水的研究进展%Progress in fluidized bed bioreactor applied to wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    冯杨阳; 廖延广; 陈英文; 沈树宝

    2014-01-01

    The fluidized bed bioreactor (FBBR) has attracted considerable interest due to the advantages,such as high treatment efficiency,high volume load,fast mass transfer and wide range of application. Its application to wastewater treatment in recent years is introduced. In addition , the main problems at present and development di-rection of fluidized bed bioreactor in the future are pointed out.%生物流化床技术因具有处理效率高、容积负荷大、传质速度快、应用范围广等优点受到了广泛的关注。介绍了近年来国内外生物流化床技术在废水处理中的应用研究情况,并指出了生物流化床技术目前存在的主要问题及今后的发展方向。

  3. Investigation on removal pathways of Di 2-ethyl hexyl phthalate from synthetic municipal wastewater using a submerged membrane bioreactor.

    Science.gov (United States)

    Zolfaghari, Mehdi; Drogui, Patrick; Seyhi, Brahima; Brar, Satinder Kaur; Buelna, Gerardo; Dubé, Rino; Klai, Nouha

    2015-11-01

    Highly hydrophobic Di 2-ethyl hexyl phthalate (DEHP) is one of the most prevalent plasticizers in wastewaters. Since its half-life in biological treatment is around 25days, it can be used as an efficiency indicator of wastewater treatment plant for the removal of hydrophobic emerging contaminants. In this study, the performance of submerged membrane bioreactor was monitored to understand the effect of DEHP on the growth of aerobic microorganisms. The data showed that the chemical oxygen demand (COD) and ammonia concentration were detected below 10 and 1.0mg/L, respectively for operating conditions of hydraulic retention time (HRT)=4 and 6hr, sludge retention time (SRT)=140day and sludge concentration between 11.5 and 15.8g volatile solid (VS)/L. The removal efficiency of DEHP under these conditions was higher and ranged between 91% and 98%. Results also showed that the removal efficiency of DEHP in biological treatment depended on the concentration of sludge, as adsorption is the main mechanism of its removal. For the submerged membrane bioreactor, the pore size is the pivotal factor for DEHP removal, since it determines the amount of soluble microbial products coming out of the process. Highly assimilated microorganisms increase the biodegradation rate, as 74% of inlet DEHP was biodegraded; however, the concentration of DEHP inside sludge was beyond the discharge limit. Understanding the fate of DEHP in membrane bioreactor, which is one of the most promising and futuristic treatment process could provide replacement for conventional processes to satisfy the future stricter regulations on emerging contaminants.

  4. Removal and Degradation Pathways of Sulfamethoxazole Present in Synthetic Municipal Wastewater via an Anaerobic Membrane Bioreactor

    KAUST Repository

    Sanchez Huerta, Claudia

    2016-05-01

    The current global water crisis in addition to continues contamination of natural water bodies with harmful organic micropollutants (OMPs) have driven the development of new water treatment technologies that allow the efficient removal of such compounds. Among a long list of OMPs, antibiotics are considered as top priority pollutants to be treated due to their great resistance to biological treatments and their potential to develop bacterial resistance. Different approaches, such as membrane-based and advance oxidation processes have been proposed to alleviate or minimize antibiotics discharge into aquatic environments. However most of these processes are costly and generate either matrices with high concentration of OMPs or intermediate products with potentially greater toxicity or persistence. Therefore, this thesis proposes the study of an anaerobic membrane bioreactor (AnMBR) for the treatment of synthetic municipal wastewater containing sulfamethoxazole (SMX), a world widely used antibiotic. Besides the general evaluation of AnMBR performance in the COD removal and biogas production, this research mainly focuses on the SMX removal and its degradation pathway. Thus 5 SMX quantification was performed through solid phase extraction-liquid chromatography/mass spectrometry and the identification of its transformation products (TPs) was assessed by gas chromatography/mass spectrometry technique. The results achieved showed that, working under optimal conditions (35°C, pH 7 and ORP around -380 to -420 mV) and after a biomass adaptation period (maintaining 0.85 VSS/TSS ratio), the AnMBR process provided over 95% COD removal and 95-98% SMX removal, while allowing stable biogas composition and methane production (≈130 mL CH4/g CODremoved). Kinetic analysis through a batch test showed that after 24 h of biological reaction, AnMBR process achieved around 94% SMX removal, indicating a first order kinetic reaction with K= 0.119, which highlights the high degradation

  5. Removal of Pathogens by Membrane Bioreactors: A Review of the Mechanisms, Influencing Factors and Reduction in Chemical Disinfectant Dosing

    Directory of Open Access Journals (Sweden)

    Faisal I. Hai

    2014-11-01

    Full Text Available The continued depletion of fresh drinking water resources throughout the world has increased the need for a variety of water treatment and recycling strategies. Conventional wastewater treatment processes rely on extensive chemical post-disinfection to comply with the stringent microbiological safety for water reuse. When well designed and operated, membrane bioreactors (MBRs can consistently achieve efficient removals of suspended solids, protozoa and coliform bacteria. Under optimal conditions, MBR systems can also significantly remove various viruses and phages. This paper provides an in-depth overview of the mechanisms and influencing factors of pathogen removal by MBR and highlights practical issues, such as reduced chemical disinfectant dosing requirements and associated economic and environmental benefits. Special attention has been paid to the aspects, such as membrane cleaning, membrane imperfections/breach and microbial regrowth, in the distribution system on the overall pathogen removal performance of MBR.

  6. A pilot scale anoxic/oxic membrane bioreactor (A/O MBR) for woolen mill dyeing wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A pilot-scale(10 m3/d) anoxic/oxic membrane bioreactor(A/O MBR) was tested for dyeing wastewater treatment of woolen millwithout wasting sludge in 125 days operation. Results showed that the effluent quality was excellent, i.e. effluent COD less than 25 mg/L,BOD5 under 5 mg/L, turbidity lower than 0.65 NTU, and colour less than 30 DT, and met with the reuse water standard of Cb. ina. The removalrates of COD, BOD5, colour, and turbidity were 92.4%, 98.4%, 74% and 98.9%, respectively. Constant-flux operation mode was carriedout in this study, and backwash was effective for reducing membrane fouling and maintaining constant flux. Membrane fouling had heavy impacton energy consumption. More attention should be paid on pipe selection and design for the sidestream MBR system, too.

  7. Isolation and molecular characterization of biofouling bacteria and profiling of quorum sensing signal molecules from membrane bioreactor activated sludge.

    Science.gov (United States)

    Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

    2014-02-04

    The formation of biofilm in a membrane bioreactor depends on the production of various signaling molecules like N-acyl homoserine lactones (AHLs). In the present study, a total of 200 bacterial strains were isolated from membrane bioreactor activated sludge and screened for AHLs production using two biosensor systems, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136. A correlation between AHLs production and biofilm formation has been made among screened AHLs producing strains. The 16S rRNA gene sequence analysis revealed the dominance of Aeromonas and Enterobacter sp. in AHLs production; however few a species of Serratia, Leclercia, Pseudomonas, Klebsiella, Raoultella and Citrobacter were also identified. The chromatographic characterization of sludge extract showed the presence of a broad range of quorum sensing signal molecules. Further identification of sludge AHLs by thin layer chromatography bioassay and high performance liquid chromatography confirms the presence of C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, C12-HSL, 3-oxo-C12-HSL and C14-HSL. The occurrence of AHLs in sludge extract and dominance of Aeromonas and Enterobacter sp. in activated sludge suggests the key role of these bacterial strains in AHLs production and thereby membrane fouling.

  8. Isolation and Molecular Characterization of Biofouling Bacteria and Profiling of Quorum Sensing Signal Molecules from Membrane Bioreactor Activated Sludge

    Directory of Open Access Journals (Sweden)

    Harshad Lade

    2014-02-01

    Full Text Available The formation of biofilm in a membrane bioreactor depends on the production of various signaling molecules like N-acyl homoserine lactones (AHLs. In the present study, a total of 200 bacterial strains were isolated from membrane bioreactor activated sludge and screened for AHLs production using two biosensor systems, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136. A correlation between AHLs production and biofilm formation has been made among screened AHLs producing strains. The 16S rRNA gene sequence analysis revealed the dominance of Aeromonas and Enterobacter sp. in AHLs production; however few a species of Serratia, Leclercia, Pseudomonas, Klebsiella, Raoultella and Citrobacter were also identified. The chromatographic characterization of sludge extract showed the presence of a broad range of quorum sensing signal molecules. Further identification of sludge AHLs by thin layer chromatography bioassay and high performance liquid chromatography confirms the presence of C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, C12-HSL, 3-oxo-C12-HSL and C14-HSL. The occurrence of AHLs in sludge extract and dominance of Aeromonas and Enterobacter sp. in activated sludge suggests the key role of these bacterial strains in AHLs production and thereby membrane fouling.

  9. Evaluation of a membrane bioreactor system as post-treatment waste water treatment for better removal of micropollutants

    DEFF Research Database (Denmark)

    Arriaga, Sonia; de Jonge, Nadieh; Lund Nielsen, Marc

    2016-01-01

    Organic micropollutants such as pharmaceuticals are persistent pollutants that are only partially degraded in waste water treatment plants (WWTPs). In this study, a membrane bioreactor (MBR) system was used as a polishing step on a full-scale WWTP, and its ability to remove micropollutants...... was examined together with the development and stability of the microbial community. Two stages of operation were studied during a period of 9 months, one with (S1) and one without (S2) the addition of exogenous organic micropollutants. Ibuprofen and naproxen had the highest degradation rates with values....... Finally, potential microbial candidates for ibuprofen and naproxen degradation are proposed....

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

    Science.gov (United States)

    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. Membrane assisted fluidized bed reactor: experimental demonstration for partial oxidation of methanol

    NARCIS (Netherlands)

    Deshmukh, Salim Abdul Rashid Khan

    2004-01-01

    In this thesis the reactor concept has been developed on the basis of an experimental study on the effect of fluidization conditions on the membrane permeation rate in a MAFBR, the extent of gas back mixing and the tube-to-bed heat transfer rates in the presence of membrane bundles with and without

  12. Heat transfer in a membrane assisted fluidized bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, Salim A.R.K.; Volkers, Sander; Sint Annaland, van Martin; Kuipers, Hans

    2005-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidized bed operated in the bubbling fluidization regime was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged

  13. Modelling of packed bed membrane reactors for autothermal production of ultrapure hydrogen

    NARCIS (Netherlands)

    Tiemersma, T.P.; Patil, C.S.; Sint Annaland, van M.; Kuipers, J.A.M.

    2006-01-01

    The conceptual feasibility of a packed bed membrane reactor for the autothermal reforming (ATR) of methane for the production of ultrapure hydrogen was investigated. By integrating H2 permselective Pd-based membranes under autothermal conditions, a high degree of process integration and intensificat

  14. Application of Membrane Bioreactor in Refractory Wastewater Treatment%膜生物反应器在难降解废水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    任永忠; 梅峰

    2011-01-01

    膜生物反应器是近年来发展的一种新型的水处理技术。本文主要介绍了膜生物反应器在印染废水、造纸废水和垃圾渗滤液等难降解废水处理中的应用以及近年来国内一些研究成果,并指出今后膜生物反应器在废水处理方面的研究方向。%Membrane bioreactor was a new type of water treatment technology developed in recent years.The application of membrane bioreactor in refractory wastewater treatment and some domestic research in recent years were introduced.The research direction of membrane bioreactor in wastewater treatment in the future was proposed.

  15. Coupling granular activated carbon adsorption with membrane bioreactor treatment for trace organic contaminant removal: breakthrough behaviour of persistent and hydrophilic compounds.

    Science.gov (United States)

    Nguyen, Luong N; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D

    2013-04-15

    This study investigated the removal of trace organic contaminants by a combined membrane bioreactor - granular activated carbon (MBR-GAC) system over a period of 196 days. Of the 22 compounds investigated here, all six hydrophilic compounds with electron-withdrawing functional groups (i.e., metronidazole, carbamazepine, ketoprofen, naproxen, fenoprop and diclofenac) exhibited very low removal efficiency by MBR-only treatment. GAC post-treatment initially complemented MBR treatment very well; however, a compound-specific gradual deterioration of the removal of the above-mentioned problematic compounds was noted. While a 20% breakthrough of all four negatively charged compounds namely ketoprofen, naproxen, fenoprop and diclofenac occurred within 1000-3000 bed volumes (BV), the same level of breakthrough of the two neutral compounds metronidazole and carbamazepine did not occur until 11,000 BV. Single-solute isotherm parameters did not demonstrate any discernible correlation individually with any of the parameters that may govern adsorption onto GAC, such as log D, number of hydrogen-bond donor/acceptor groups, dipole moment or aromaticity ratio of the compounds. The isotherm data, however, could differentiate the breakthrough behaviour between negatively charged and neutral trace organic contaminants.

  16. Evaluation of system performance and microbial communities of a bioaugmented anaerobic membrane bioreactor treating pharmaceutical wastewater.

    Science.gov (United States)

    Ng, Kok Kwang; Shi, Xueqing; Ng, How Yong

    2015-09-15

    In this study, a control anaerobic membrane bioreactor (C-AnMBR) and a bioaugmented anaerobic membrane bioreactor (B-AnMBR) were operated for 210 d to treat pharmaceutical wastewater. Both the bioreactors were fed with the pharmaceutical wastewater containing TCOD of 16,249 ± 714 mg/L and total dissolved solids (TDS) of 29,450 ± 2209 mg/L with an organic loading rate (OLR) of 13.0 ± 0.6 kgCOD/m(3)d. Under steady-state condition, an average total chemical oxygen demand (TCOD) removal efficiency of 46.1 ± 2.9% and 60.3 ± 2.8% was achieved by the C-AnMBR and the B-AnMBR, respectively. The conventional anaerobes in the C-AnMBR cannot tolerate the hypersaline conditions well, resulting in lower TCOD removal efficiency, biogas production and methane yield than the B-AnMBR seeded from the coastal shore. Pyrosequencing analysis indicated that marine bacterial species (Oliephilus sp.) and halophilic bacterial species (Thermohalobacter sp.) were only present in the B-AnMBR; these species could possibly degrade complex and recalcitrant organic matter and withstand hypersaline environments. Two different dominant archaeal communities, genus Methanosaeta (43.4%) and Methanolobus (61.7%), were identified as the dominant methanogens in the C-AnMBR and the B-AnMBR, respectively. The species of genus Methanolobus was reported resistant to penicillin and required sodium and magnesium for growth, which could enable it to thrive in the hypersaline environment.

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

    Science.gov (United States)

    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.

  18. Acetone-butanol-ethanol fermentation in a continuous and closed-circulating fermentation system with PDMS membrane bioreactor.

    Science.gov (United States)

    Chen, Chunyan; Xiao, Zeyi; Tang, Xiaoyu; Cui, Haidi; Zhang, Junqing; Li, Weijia; Ying, Chao

    2013-01-01

    Acetone-butanol-ethanol (ABE) fermentation by combining a PDMS membrane bioreactor and Clostridium acetobutylicum was studied, and a long continuous and closed-circulating fermentation (CCCF) system has been achieved. Two cycles of experiment were conducted, lasting for 274 h and 300 h, respectively. The operation mode of the first cycle was of fermentation intermittent coupling with pervaporation, and the second cycle was of continuous coupling. The average cell weight, glucose consumption rate, butanol productivity and butanol production of the first cycle were 1.59 g L(-1), 0.63 g L(-1)h(-1), 0.105 g L(-1)h(-1) and 28.03 g L(-1), respectively. Correspondingly, the four parameters of the second cycle were 1.68 g L(-1), 1.12 g L(-1)h(-1), 0.205 g L(-1)h(-1) and 61.43 g L(-1), respectively. The results indicate the fermentation behaviors under continuous coupling mode were superior to that under intermittent coupling mode. Besides, two peak values were observed in the time course profiles, which means the microorganism could adapt the long CCCF membrane bioreactor system. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  20. Membrane bioreactor and nanofiltration hybrid system for reclamation of municipal wastewater: removal of nutrients, organic matter and micropollutants.

    Science.gov (United States)

    Chon, Kangmin; KyongShon, Ho; Cho, Jaeweon

    2012-10-01

    A membrane bioreactor (MBR) and nanofiltration (NF) hybrid system was investigated to demonstrate the performance of treating nitrogen, phosphorus and pharmaceuticals and personal care products (PPCPs) in municipal wastewater. With the MBR and NF (molecular weight cut off (MWCO): 210 Da), the concentration of total nitrogen (TN) and total phosphorus (TP) was effectively reduced by nitrification by MBR and negatively charged surface of NF (TN: 8.67 mgN/L and TP: 0.46 mgP/L). Biosorption and microbial decomposition in MBR seem to be major removal mechanisms for the removal of PPCPs. Among various parameters affecting the removal of PPCPs by NF, namely, physicochemical properties of the PPCPs (charge characteristics, hydrophobicity and M(W)) and membranes (MWCO and surface charge), the MWCO effect was found to be the most critical aspect.