Performance Of Membrane Bioreactor Research Articles

Membrane bioreactor (MBR) performance in fish canning industrial wastewater treatment

Abstract The fish canning industries produce a large amount of wastewater. The high-strength wastewater from fish processing industry is of great concern worldwide. This type of wastewater is rich in organic matter and has high total dissolved solids (TDS). The elimination of salts is usually expensive and, on the other hand, the high salinity and the seasonal variation of the effluent characteristics make the removal of organic matter difficult using only a biological process. For this purpose, the use of a membrane bioreactor (MBR) process combining both a biological treatment and ultrafiltration membrane separation could be a perfect option for fish canning wastewater treatment. In this work, the performance of a MBR process is investigated to treat the fish canning industry wastewater. The removal efficiency of important parameters such as chemical oxygen demand (COD), five day-biological oxygen demand in (BOD5), total suspended solids (TSS), nitrate (NO3−), total Kjeldahl nitrogen (TKN), orthophosphate (PO43−) and TDS are followed. Experimental results show that the overall removal efficiencies obtained are: 96.6% for COD, 98% for BOD, 99.5% for TSS, 90% for nitrate, 96% for TDS and greater than 97% for TKN and PO43−. These results confirm that combination of both biological treatment and membrane process is regarded as an effective approach to reduce the contaminants in fish canning wastewater. Membrane bioreactor presents several advantages in terms of water resource protection because of the great quality of the treated water that can be reused.

Promotion and mechanisms of Bdellovibrio sp. Y38 on membrane fouling alleviation in membrane bioreactor

Membrane fouling is a major bottleneck limiting the widespread application of membrane bioreactors (MBR). In this study, Bdellovibrio sp. Y38, an obligate bacteriophage bacterium of Bdellovibrio-and-like organisms (BALOs), was enriched into highly concentrated culture medium (106-107 PFU/mL), and daily dosed into the MBR to investigate its effects on membrane fouling mitigation. The strain Y38 prolonged the membrane fouling cycle from 73 days to 90 days, indicating its membrane fouling alleviation potentials. The concentration of BALOs was increased 625 times higher than the control group after the whole operation, resulting in the concentration of chemical oxygen demand and nucleic acids in the liquid phase of the MBR system being significantly increased by 169.8 ± 1.5% and 126.7 ± 2.2%, respectively. The biomass growth rate was reduced by 27.2 ± 0.7% from day 0 to day 54. These results indicated the predation potential of Bdellovibrio sp. Y38 on the microorganisms in the sludge. The improvement of homogenized sludge and filtration and settling performance by the strain Y38 alleviated the membrane fouling. Compared with the control group, the macromolecular proteins in SMP and EPS were partially declined, and the polysaccharide in EPS decreased by 14.0 ± 3.9%, and the ratios of protein content to polysaccharide content (PN/PS) in SMP and EPS significantly increased by 35.6 ± 16.8% and 57.8 ± 6.1% at the middle stage, respectively, indicating the strain Y38 could alleviate membrane fouling by reducing and modifying SMP and EPS. Furthermore, the relative abundance of γ-proteobacteria decreased from 13.2% to 5.1% at the pre-middle stage, and Planctomycetes decreased from 1.5% to 0.8% at the end-stage, which were probably responsible for the membrane fouling mitigation. In addition, the strain Y38 had few impacts on the water treatment performance of MBR. There findings provide a promising strategy for in situ membrane pollution mitigation via exogenous additions of BALOs.

Towards a Better Understanding of Long-Term Self-Forming Dynamic Membrane Bioreactor (SFDMBR) Performance: Effect of Aeration Intensity

This study aims to provide valuable new insights regarding the effect of aeration intensity on long-term self-forming dynamic membrane bioreactor (SFDMBR) performance and the associated mechanisms. Three identical SFDMBRs, with different aeration intensities (i.e., 200, 500 and 800 L/h), were operated in constant transmembrane (TMP) mode for 60 days. The best chemical oxygen demand (COD) removal performance was achieved at medium aeration intensity, owing to the enhanced COD removal contribution by the self-forming dynamic membrane (SFDM). As expected, the SFDM formation time was extended with increasing aeration intensity. Different from the initial short-term stage results, it was interestingly found that the SFDMBR operated at medium aeration intensity exhibited the best long-term filtration performance, followed in order by the SFDMBRs with low and high aeration intensity, respectively. Further analysis revealed that the governing fouling mechanism transited from biomass accumulation to the increase of specific resistance, as aeration intensity increased. The variation of SFDM-specific resistance was verified with particle size distribution (PSD) data and scanning electron microscopy (SEM) images. The long-term increasing rate of SFDM filtration resistance was consistent with both extracellular polymeric substances (EPS) content and the proteins/polysaccharides (PN/PS) ratio of SFDMs. Internal EPS production was enhanced in the thicker SFDM formed at a lower aeration intensity.

Effect of powdered activated carbon addition on membrane performance and fouling in anaerobic membrane bioreactor

Effect of powdered activated carbon addition on membrane performance and fouling in anaerobic membrane bioreactor

Pilot plant demonstration of temperature impacts on the methanogenic performance and membrane fouling control of the anaerobic membrane bioreactor in treating real municipal wastewater

A 5,000-L anaerobic membrane bioreactor (AnMBR) fed with actual municipal wastewater was employed to study the impact of temperature drops on methanogenic performance and membrane fouling. With temperature dropped from 25 °C to 15 °C, the methane yield decreased from 0.244 to 0.205 NL-CH4/g-CODremoval and the dissolved methane increased from 29% to 43%, resulted in the methanogenic performance reduced by 25%. The membrane rejection offset the deteriorated anaerobic digestion at low temperatures and ensured the stable COD removal efficiency of 84.5%-90.0%. The synergistic effects of the increased microbial products and viscosity and the residual inorganic foulants aggravated the membrane fouling at lower temperatures. As the organic fouling was easily removed by NaClO, the inorganics related to the elements of S, Ca and Fe were the stubborn membrane foulants and required the enhanced acid membrane cleaning. These findings obtained under the quasi-practical condition are expected to promote the practical applications of mainstream AnMBR.

Nitrification performance and bacterial community dynamics in a membrane bioreactor with elevated ammonia concentration: The combined inhibition effect of salinity, free ammonia and free nitrous acid on nitrification at high ammonia loading rates

The responses of the operational performance and bacterial community structure of a nitrification membrane bioreactor (MBR) to elevated ammonia loading rate (ALR) were investigated. Effective nitrification performance was achieved at high ALR up to 3.43 kg NH4+-N/m3·d, corresponding to influent NH4+-N concentration of 2000 mg/L. Further increasing influent NH4+-N concentration to 3000 mg/L, the MBR system finally became completely inefficient due to the combined inhibition effect of salinity, free ammonia and free nitrous acid on nitrification. Ammonia-oxidizing bacteria (AOB) Nitrosomonas were enriched with the increase of ALR. The relative abundance of Nitrosomonas in the sludge with ALR of 2.57 kg NH4+-N/m3·d was up to 14.82%, which were 9-fold and 53-fold higher than that in seed sludge and the sludge with ALR of 0.10 kg NH4+-N/m3·d, respectively. The phylogenetic analysis of AOB amoA genes showed that Nitrosomonas europaea/mobilis lineage are chiefly responsible for catalyzing ammonia oxidation at high ALRs.

Effect of Aeration Intensity on Performance of Lab-Scale Quorum-Quenching Membrane Bioreactor.

Biofouling is one of the main drawbacks of membrane bioreactors (MBRs). Among the different methods, the quorum-quenching (QQ) technique is a novel method as it delays biofilm formation on the membrane surface through disruption of bacterial cell-to-cell communication and thus effectively mitigates membrane biofouling. QQ bacteria require a certain concentration of dissolved oxygen to show their best activities. Despite the importance of the amount of aeration, there have not been enough studies on aeration condition utilizing the separate determination of pure QQ effect and physical cleaning effect. This research aimed to find the optimum aeration intensity by separation of the two effects from QQ and physical cleaning. Three bead type conditions (no bead, vacant bead, and QQ beads) at three aeration intensities (1.5, 2.5, and 3.5 L/min representing low, medium, and high aeration intensity) were applied. From the results, no QQ effect and small QQ effect were observed at low and high aeration, while the greatest QQ effect (48.2% of 737 h improvement) was observed at medium aeration. The best performance was observed at high aeration with QQ beads having a 1536 h operational duration (303% improvement compared to the no bead condition); however, this excellent performance was attributed more to the physical cleaning effect than to the QQ effect.

Change of extracellular polymeric substances and microbial community in biofouling mitigation by continuous vanillin dose in membrane bioreactor

Vanillin ― a bioactive substance to interfere various biological activities ― is reportedly able to mitigate fouling in a membrane bioreactor (MBR). However, impact of continuous dose of vanillin on treatment performance and microbial activities in MBR are still unknown. In this study, effects of vanillin on production of extracellular polymeric substances (EPS) and microbial community was investigated in lab-scale MBR under continuous dose of vanillin. Vanillin dose remarkably reduced membrane fouling in accordance with less development of cake layer. It was probably because bulk sludge contained more hydrophilic components and became less adhesive by lower abundance of Xanthomonadaceae and Chitonophagaceae, which are known to produce viscous EPS and hydrophobic lipopolysaccharides. In addition, filtration resistance of cake layer was probably reduced by less contents of SMP and LB-EPS due to inhibition of Flavobacterium and Xanthomonadaceae, which are biofilm forming bacteria and EPS producers. These results suggest that interference to microbial activity by continuous dose of vanillin alters characteristics of sludge EPS, thus effectively mitigate biofouling in MBR.

Impact of permeate flux and gas sparging rate on membrane performance and process economics of granular anaerobic membrane bioreactors

This research investigated the impact of permeate flux and gas sparging rate on membrane permeability, dissolved and colloidal organic matter (DCOM) rejection and process economics of granular anaerobic membrane bioreactors (AnMBRs). The goal of the study was to understand how membrane fouling control strategies influence granular AnMBR economics. To this end, short- and long-term filtration tests were performed under different permeate flux and specific gas demand (SGD) conditions. The results showed that flux and SGD conditions had a direct impact on membrane fouling. At normalised fluxes (J20) of 4.4 and 8.7 L m−2 h−1 (LMH) the most favourable SGD condition was 0.5 m3 m−2 h−1, whereas at J20 of 13.0 and 16.7 LMH the most favourable SGD condition was 1.0 m3 m−2 h−1. The flux and the SGD did not have a direct impact on DCOM rejection, with values ranging between 31 and 44%. The three-dimensional excitation-emission matrix fluorescence (3DEEM) spectra showed that protein-like fluorophores were predominant in mixed liquor and permeate samples (67–79%) and were retained by the membrane (39–50%). This suggests that protein-like fluorophores could be an important foulant for these systems. The economic analysis showed that operating the membranes at moderate fluxes (J20 = 7.8 LMH) and SGD (0.5 m3 m−2 h−1) could be the most favourable alternative. Finally, a sensitivity analysis illustrated that electricity and membrane cost were the most sensitive economic parameters, which highlights the importance of reducing SGD requirements and improving membrane permeability to reduce costs of granular AnMBRs.

Simultaneously enhanced treatment efficiency of simulated hypersaline azo dye wastewater and membrane antifouling by a novel static magnetic field membrane bioreactor (SMFMBR)

Operation performance and membrane fouling of a novel static magnetic field membrane bioreactor (SMFMBR) for treatment of hypersaline azo dye wastewater was investigated. The results showed that SMFMBRs possessed higher efficiency of dye decolorization, COD removal and detoxification than the control MBR without SMF. The (3#) SMFMBR equipped with 305.0 mT (the highest intensity) SMF displayed the best treatment performance among all the four reactors (named as 0#–3#, equipped with SMFs of 0 mT, 95.0 mT, 206.3 mT and 305.0 mT, respectively). Potentially effective microbes belonging to Rhodanobacter, Saccharibacteria genera incertae sedis, Defluviimonas, Cellulomonas, Cutaneotrichosporon, Candida and Pichia were enriched in three SMFMBRs, in both of suspended sludge and bio-cakes. The relative abundance of Candida and Pichia in suspended sludge of 3# SMFMBR was the highest among all the four reactors, suggesting their successful colonization and potentially persistent effect of bioaugmentation. On the other hand, SMF of higher intensity effectively mitigated membrane fouling. Less production of soluble microbial products (SMP) and extracellular polymeric substances (EPS), lower protein/polysaccharide (PN/PS) ratio in SMP and EPS, looser structure of bio-cakes on membrane surface, as well as lower relative abundance of potential fouling causing microbes (mainly bacteria) in microbial communities were determined in 3# SMFMBR than the other three groups.

Unrevealing the role of in-situ Fe(II)/S2O82- oxidation in sludge solid–liquid separation and membrane fouling behaviors of membrane bioreactor (MBR)

Membrane bioreactor (MBR) has received continuous attention in waste activated sludge treatment, however, membrane fouling still remains a big and inevitable challenge to its wide applications. Ferrous-persulfate (Fe(II)/S2O82–) oxidation possesses the outstanding oxidizing capability and high-efficiency in degrading refractory organics and enhancing sludge solubilization. In this study, in-situ Fe(II)/S2O82- oxidation was coupled for pretreating sludge, and the effect on the subsequent filtration performance and membrane fouling behaviors in MBR was investigated. Fe(II)/S2O82- oxidation had an outstanding effect on enhancing filterability of mixed sludge liquor and alleviating membrane fouling. Under the optimal pretreatment condition of 1.5/1.2 mmol-Fe(II)-S2O82-/g-VS, the membrane flux of reactor reached 20.6 mL/s/m2, and a 46.6% decrease in trans-membrane pressure (TMP) was obtained compared to the raw sludge without pretreatment. Correlation analysis reveal that polysaccharides in extracellular polymeric substances was the decisive factor affecting the membrane fouling behavior. The strong oxidizing ability of in-situ Fe(II)/S2O82- pretreatment could effectively break the glutinous and pilotaxitic biopolymer matrix deposited on the membrane surface, and rupture the hydrophilic bonds of proteins and polysaccharides. The high molecular weight biopolymers were brought down, with the water bounded inside the flocs released into liquid phase. Iron-mediated coagulation was also conductive to the re-aggregation of the fine particles and subsequent membrane fouling control. For raw sludge, the predominated fouling mechanisms were intermediate pore blocking and cake layer formation, while complete pore blocking and standard pore blocking occurred more frequently for pretreated sludge. This work provides a promising approach based on Fe(II)/S2O82- oxidation processes for efficient abatement of membrane fouling and sludge treatment.

Impact of different inoculum sources on the performance of membrane bioreactors for municipal wastewater treatment: Dynamic membrane versus ultrafiltration membrane

In this study, impact of different inoculum on the performance of membrane bioreactors (MBRs) was investigated for municipal wastewater treatment. Waste sludges from a conventional activated sludge (CAS) system and a high-rate activated sludge (HRAS) system were used as inoculums at Stage-1 and Stage-2, respectively. A commercial ultrafiltration (UF) membrane was tested in parallel with a low-cost polyester hollow fiber support material (dynamic membrane, DM). UF and DM membranes were operated for 67 days at a flux of 8 L/m2·h at each stage. High chemical oxygen demand (COD) and soluble COD (sCOD) removal efficiencies (>86% and >74%, respectively), low mixed liquor suspended solids (MLSS) concentration (<10 mg/L), and low turbidity values were achieved in permeates at each stage. Extracellular polymeric substances (EPS) content was higher at Stage-1, which caused an increase in sludge resistance to filtration (SRF) and sludge volume index (SVI). Based on morphological analysis, compact dynamic cake layer was formed on the support material at Stage-1, while porous dynamic layer was formed at Stage-2. Thus, DM was operated at lower TMP at Stage-2. Based on the results obtained from the study, sludge from HRAS system showed better performance as inoculum compared to the sludge from CAS system for DM applications.

Dynamic modeling of a full-scale membrane bioreactor performance for landfill leachate treatment.

Leachate treatment is crucial in landfill management. As landfill ages, inert constituents and ammonia nitrogen concentration in leachate increases, which results in a decrease in biological treatability. In this study, a full-scale MBR treating leachate was dynamically modeled using ASM1. The investigated landfill has been serving for more than 25years; thus, a decrease in biodegradable organic content and an increase in nitrogen content of the leachate is expected in the years ahead. The calibrated model predicted MLSS, effluent COD, and effluent TN concentrations with high accuracy. Following the calibration study, it was found that soluble inert COD and soluble inert organic nitrogen fractions were the primary reasons ofhigh COD and TKN concentrations in the effluent, respectively. The validated model of the full-scale MBR system treating leachate can be a useful tool to understand the limitations of the system. Soluble inert constituents of the leachatethat pass through the membranenecessiate additional treatment processesfor discharge into surface water bodies.

Long Term Operation Performance and Membrane Fouling Mechanisms of Anaerobic Membrane Bioreactor Treating Waste Activated Sludge at High Solid Concentration and High Flux

Long Term Operation Performance and Membrane Fouling Mechanisms of Anaerobic Membrane Bioreactor Treating Waste Activated Sludge at High Solid Concentration and High Flux

Experimental Investigation of the Performance of Anaerobic Membrane Bioreactor with Electrolytic Regeneration (Amber) for Challenges and Options in Wastewater Treatment

Experimental Investigation of the Performance of Anaerobic Membrane Bioreactor with Electrolytic Regeneration (Amber) for Challenges and Options in Wastewater Treatment

Long Term Operation Performance and Membrane Fouling Mechanisms of High Solid Anaerobic Membrane Bioreactor Treating Waste Activated Sludge in a Wide Range of Total Solid and Flux

Long Term Operation Performance and Membrane Fouling Mechanisms of High Solid Anaerobic Membrane Bioreactor Treating Waste Activated Sludge in a Wide Range of Total Solid and Flux

The performance of electrode ultrafiltration membrane bioreactor in treating cosmetics wastewater and its anti-fouling properties

The membrane fouling problem of the membrane bioreactor (MBR) for wastewater treatment reduces the membrane flux and the pollutants removal efficiencies, which is the major obstacle limiting its application and should be properly solved. The combination of membrane and electricity can effectively slow down the membrane fouling rate due to electric repulsion between the pollutants and the membrane. In this study, the performance and the membrane fouling features of an electrode ultrafiltration membrane bioreactor (EMBR) fed with cosmetics wastewater were compared with a conventional ultrafiltration membrane bioreactor (UMBR). The results showed the COD removal efficiency increased by 4.43% and the transmembrane pressure (TMP) reduced by 50% in the EMBR as compared with the UMBR. The specific surface areas of electrode ultrafiltration membrane and conventional ultrafiltration membrane declined by 56.9% and 78.8% after 90 days of operation, respectively. The Protein (PN), polysaccharide (PS) and humic acids (HA) in the cake layer of EMBR were only 61.27%, 78.37% and 34.85% of that of UMBR, which contributed to its loose and porous structure and thus decreased the growth rate of TMP and extended the operation cycle. Extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory calculation proved that the energy barrier between the electrode ultrafiltration membrane and the pollutants was 50% higher than that between the conventional ultrafiltration membrane and the pollutants. Therefore, the strong anti-fouling property of the electrode ultrafiltration membrane could reduce the chemicals dosage and manpower consumption for membrane cleaning and could be preferred for the treatment of cosmetics or alike wastewater containing high concentrations of surfactants and fatty acids.

Role of nano-Fe3O4 particle on improving membrane bioreactor (MBR) performance: Alleviating membrane fouling and microbial mechanism

This study would investigate the effect of nano-Fe3O4 particles on the performance of membrane bioreactor (MBR), including membrane fouling, membrane rejection and microbial community. It can effectively alleviate membrane fouling and improve the effluent quality in MBR by bio-effect rather than nanoparticle adsorption. The lowest membrane fouling resistance was achieved at R4-MBR (sludge and membrane surface with nano-Fe3O4), which decreased by 46.08%. Meanwhile, R3-MBR (sludge with nano-Fe3O4) had the lowest concentration of COD in effluent which was below 20 mg/L in the stable phase of MBR operation. After applying nano-Fe3O4, the content of extracellular polymeric substances (EPS) and soluble microbial products (SMP) were both reduced with a lower molecular weight. From the microbial community analysis, the abundance of Proteobacteria increased from 25.06 to 45.11% at the phylum level in R3-MBR. It contributed to removing organic substances in MBRs. Moreover, the nano-Fe3O4 restricted Bacteroidetes growth, especially in R4-MBR, leading to a more excellent performance of membrane flux. Besides, the applied nano-Fe3O4 promoted the abundance of Quorum Quenching (QQ) microorganism, and declined the percentage of Quorum Sensing (QS) bacteria. Then, a lower content of N-Acyl-l-Homoserine Lactones (AHLs) in containing nano-Fe3O4 sludge. That was also prone to control membrane fouling. Overall, this study indicates the nano-Fe3O4 particle is appropriate for elevating MBR performance, such as membrane fouling and effluent quality, by bio-effect.

Influence of organic loading rates on treatment performance of membrane bioreactor treating tannery wastewater

Tannery wastewater contains high pollutants concentrations such as nitrogen, organic matter, salinity, toxic metals, etc. Membrane bioreactor has been widely recognized as potential technology for wastewater treatment and reuse. Finding proper operating conditions and a strategy for fouling mitigation in MBR process is essential to application to tannery wastewater treatment. Herein, this study investigated the effect of organic loading rate (OLR) on the performance and fouling behavior of membrane bioreactor (MBR) treating tannery wastewater during 280 days of operation. The MBR was operated under the low fluxes of 4.2 and 8.3 L m−2 h−1, corresponding to organic loading rates of 1.3 (OLR1) and 2.6 kg COD m−3d−1 (OLR2). The results show that the COD removal was obtained at 78 ± 19% and 89 ± 2% for OLR1 and OLR2, respectively. For the former condition the average removal of total Kjeldahl nitrogen (TKN) and NH4+-N reached 53%–68% and 58%–70%. TKN removal was mainly contributed by cell assimilation. Incomplete nitrification was due to high TDS (11,000–16,790 mg L−1) and the presence of free ammonia ( 6.77–31.11 mg L−1) concentrations under pH 8.7–8.8. Membrane fouling rate was strongly governed by operated flux. At flux of 4.2 LMH the fouling rate was as low as 0.19–0.4 kPa d−1 while the fouling rate accelerated (1.87–1.93 kPa d−1) as increased two times flux . These findings proposed a low flux of 4.2 LMH for MBR operation in treating real tannery wastewater. It was found that influent total suspended solids (TSS) played a crucial factor in spiking mixed liquor suspended solids (MLSS) into MBR. Thus, a pretreatment process is suggested to remove major suspended solids from raw tannery wastewater prior to biological treatment.

Efficient nitrate and perchlorate removal from aqueous solution via a novel electro-dialysis ion-exchange membrane bioreactor

The performance of a novel Electro-dialysis ion-exchange membrane bioreactor (EDIMB) for simultaneous removal of perchlorate and nitrate from aqueous solution was studied. EDIMB combines electrodialysis (ED) with bioreduction to remove contaminants while avoiding secondary contamination of organic matter and microorganisms. The removal process of pollutants in water compartment and bio-compartment can be well simulated by the First-order kinetic model and the established Zero-Michaelis-Menten model. Furthermore, compared with ED (VSS = 0.00 g/L), when the microbial concentration was 3.00 g/L, the total current efficiency was increased by 43.5% in first 60 min. The biological reaction takes place in the bio-compartment, which reduces the resistance of pollutant transmembrane migration and promotes ion migration. Microorganisms played a promoting role in the process of pollutant migration. High-throughput sequencing analysis of microorganisms showed that Thauera and Macellibacteroides were the main denitrifying and perchlorate-reducing bacteria.