Anaerobic Membrane Bioreactor Effluent Research Articles

Boosting nutrient recovery from AnMBR effluent by means of electrodialysis technology: Operating parameters assessing

This work describes a comprehensive assessment of operating parameters of a bench-scale electrodialysis (ED) plant for nutrient concentration from an Anaerobic Membrane BioReactor (AnMBR) effluent. The ED bench-scale plant serves a dual purpose. Firstly, to generate a concentrated stream with a high nutrient content, and secondly, to produce high-quality reclaimed water in the diluted stream, both sourced from real wastewater coming from the effluent of an AnMBR. Two sets of experiments were conducted: 1) short-term experiments to study the effect of some parameters such as the applied current and the type of anionic exchange membrane (AEM), among others, and 2) a long-term experiment to verify the feasibility of the process using the selected parameters. The results showed that ED produced concentrated ammonium and phosphate streams using a 10-cell pair stack with 64 cm2 of unitary effective membrane area, working in galvanostatic mode at 0.24 A, and operating with an Acid-100-OT anionic exchange membrane. Concentrations up to 740 mg/L and 50 mg/L for NH4–N and PO4–P, respectively, were achieved in the concentrated stream along with removal efficiencies of 70% for ammonium and 60% for phosphate in the diluted stream. The average energy consumption was around 0.47 kWh·m−3.

Demo-scale up-flow anaerobic sludge blanket reactor coupled with hybrid constructed wetlands for energy-carbon efficient agricultural wastewater reuse in decentralized scenarios

The impact of climate change on water availability and quality has affected agricultural irrigation. The use of treated wastewater can alleviate water in agriculture. Nevertheless, it is imperative to ensure proper treatment of wastewater before reuse, in compliance with current regulations of this practice. In decentralized agricultural scenarios, the lack of adequate treatment facilities poses a challenge in providing treated wastewater for irrigation. Hence, there is a critical need to develop and implement innovative, feasible, and sustainable treatment solutions to secure the use of this alternative water source. This study proposes the integration of intensive treatment solutions and natural treatment systems, specifically, the combination of up-flow anaerobic sludge blanket reactor (UASB), anaerobic membrane bioreactor (AnMBR), constructed wetlands (CWs), and ultraviolet (UV) disinfection. For this purpose, a novel demo-scale plant was designed, constructed and implemented to test wastewater treatment and evaluate the capability of the proposed system to provide an effluent with a quality in compliance with the current European wastewater reuse regulatory framework. In addition, carbon-sequestration and energy analyses were conducted to assess the sustainability of the proposed treatment approach. This research confirmed that UASB rector can be employed for biogas production (2.5 L h−1) and energy recovery from organic matter degradation, but its effluent requires further treatment steps to be reused in agricultural irrigation. The AnMBR effluent complied with class A standards for E. coli, boasting a concentration of 0 CFU 100 mL−1, and nearly negligible TSS levels. However, further reduction of BOD5 (35 mg L−1) is required to reach water quality class A. CWs efficiently produced effluent with BOD5 below 10 mg L−1 and TSS close to 0 mg L−1, making it suitable for water reuse and meeting class A standards. Furthermore, CWs demonstrated significantly higher energy efficiency compared to intensive treatment systems. Nonetheless, the inclusion of a UV disinfection unit after CWs was required to attain water class B standards.

UV/TiO2 photocatalysis as post-treatment of anaerobic membrane bioreactor effluent for reuse

Advanced oxidation processes have been widely applied as a post-treatment solution to remove residual organic compounds in water reuse schemes. However, UV/TiO2 photocatalysis, which provides a sustainable option with no continuous chemical addition, has very rarely been studied to treat anaerobically treated effluents. In the current study, the removal of organics and nutrients from an anaerobic membrane bioreactor (AnMBR) effluent is evaluated during adsorption and photocatalysis processes under various conditions of TiO2 dose and UV intensity and compared to the effluent from an aerobic membrane bioreactor (AeMBR). The sequence for preferential adsorption on TiO2 was found to be phosphorus, inorganic carbon and then ammonia/organic carbon were found. The competing effect between the organics and nutrients, along with the low UV transmission efficiency caused by the need for high doses of TiO2, ultimately compromise the organic removal efficiency in the AnMBR permeate. TiO2 dosage was found to have a greater impact than UV intensity on improving the overall removal performance as nutrients are competing for the adsorption site but are not photodegraded. Under the same operational condition, the UV/TiO2 photocatalysis displayed a higher removal efficiency of organic matter and phosphorus in the AeMBR effluent due to a lower initial organics concentration and absence of ammonia as compared to the AnMBR effluent.

Treatment and recovery of phosphate from submerged anaerobic membrane bioreactor effluent using thermally treated biowaste and powder activated carbon

This study presents a novel treatment system using a submerged anaerobic membrane bioreactor (SAnMBR) followed by adsorption onto thermally treated biowaste, and ending with a final treatment using powdered activated carbon (PAC). Despite limited phosphate and ammonium ion removal during SAnMBR operation, thermally treated eggshell (EGSL) and seagrass (SG) received SAnMBR effluent and enhanced phosphate recovery, achieving removal rates of 71.8–99.9% and 60.5–78.0%, respectively. The SAnMBR achieved an 85% COD removal, which was slightly reduced further by biowaste treatment. However, significant further reductions in COD to 20.2 ± 5.2 mg/L for EGSL effluent and 57.0 ± 13.3 mg/L for SG effluent were achieved with PAC. Phytotoxicity tests showed the SAnMBR effluent after PAC treatment notably improved seed growth compared to untreated wastewater. In addition, volatile organic compounds (VOCs) were significantly reduced in the system, including common wastewater contaminants such as dimethyl disulfide, dimethyl trisulfide, phenol, p-cresol, nonanal, and decanal. Fractionation analysis of the solid fraction, post-adsorption from both synthetic and domestic wastewater, indicated that for SG, 77.3%–94% of the total phosphorus (TP) was inorganically bound, while for EGSL, it ranged from 94% to 95.3%. This study represents the first attempt at a proof-of-concept for simultaneous treatment of domestic wastewater and phosphorus recovery using this integrated system.

Antibiotic resistance genes fate during food waste management – Comparison between thermal treatment, hyperthermophilic composting, and anaerobic membrane bioreactor

The fate of eight different antibiotic resistance genes (ARGs) in food waste (sul1, sul2, tetO, tetW, ermF, ermB, ampC, oxa-1), intI1, and rpoB were monitored during thermal treatment (pyrolysis and incineration), hyperthermophilic composting, and anaerobic membrane bioreactor (AnMBR) treatment. ARGs in food waste ranged from 2.9 × 106 to 3.5 × 109 copies/kg with ampC being the least abundant and sul1 being the most abundant. Thermal treatment achieved removal below detection limits of all ARGs. Only two ARGs (sul1 and ampC) persisted in hyperthermophilic composting. While all genes except for ermB decreased in the AnMBR effluent relative to the food waste feed, sul1 remained at relatively high abundance. Biosolids on the contrary, accumulated tetO, ampC and sul2 in all tested operating conditions. Thermal treatment, despite limited resource recovery, provides the most effective mitigation of ARG risk in food waste.

Biomass generation and heterologous isoprenoid milking from engineered microalgae grown in anaerobic membrane bioreactor effluent

Wastewater (WW) treatment in anaerobic membrane bioreactors (AnMBR) is considered more sustainable than in aerobic reactors. However, outputs from AnMBR are a mixed methane and carbon dioxide gas stream as well as ammonium- (N) and phosphate- (P) containing waters. Using AnMBR outputs as inputs for photoautotrophic algal cultivation can strip the CO2 while removing N and P from effluent which feed algal biomass generation. Recent advances in algal engineering have generated strains that produce high-value side products concomitant with biomass, although only shown in heavily domesticated, lab-adapted strains. Here, it was investigated whether engineered Chlamydomonas reinhardtii could be grown directly in AnMBR effluent with CO2 concentrations found in AnMBR off-gas. The strain was found to proliferate over bacteria in the non-sterile effluent, consume N and P to levels that meet general discharge or reuse limits, and tolerate cultivation in modelled (extreme) outdoor environmental conditions prevalent along the central Red Sea coast. In addition to ∼2.4 g CDW L–1 biomass production in 96 h, a high-value heterologous sesquiterpene co-product could be obtained from ‘milking’ up to 837 µg L–1 culture in 96 h. This is the first demonstration of a combined bio-process that employs a heavily engineered algal strain to enhance the product generation potentials from AnMBR effluent treatment. This study shows it is possible to convert waste into value through use of engineered algae while also improving wastewater treatment economics through co-product generation.

Metagenomic Analysis of the Antibiotic Resistance Risk between an Aerobic and Anaerobic Membrane Bioreactor

Membrane bioreactors are advanced treatment technologies that, compared to conventional treatment processes, are expected to reduce antibiotic resistance spread in the environment due to their superior biomass retention. In this study, metagenomic sequencing was used to assess the response of the microbial community and antibiotic resistance profile of an aerobic membrane bioreactor (AeMBR) and an anaerobic membrane bioreactor (AnMBR) operated in parallel, treating identical synthetic wastewater supplemented with select antibiotics. Our results revealed a greater antibiotic impact on the microbial community and antibiotic resistance gene (ARG) proliferation within the AeMBR compared to the AnMBR. Moreover, antibiotic loading elicited a more pronounced disruption of the microbial diversity of the AeMBR biomass and effluent intracellular DNA compared to its AnMBR counterpart. Under antibiotic loading, the AeMBR effluent enriched ARGs in the form of antibiotic-resistant bacteria, while the AnMBR effluent enriched a wide set of extracellular ARGs across a broad spectrum of resistance classes. These results provide a theoretical basis for process selection and controlling the spread of ARGs during wastewater management.

Enhanced nutrient removal and bioenergy production in microalgal photobioreactor following anaerobic membrane bioreactor for decarbonized wastewater treatment

This study investigated the nutrient removal, decarbonization potentials, and bioenergy production (i.e., algal biomass and biogas) between a membrane photobioreactor (MPBR) and a sequencing photobioreactor (SPBR) as the post-treatment process of an anaerobic membrane bioreactor (AnMBR) for municipal wastewater treatment. All photobioreactors without aeration showed favourable performance on AnMBR effluent polishing and bioenergy production. In comparison, MPBRs achieved higher removal efficiencies with 98.4 %−99.1 % NH4-N and 74.8 %−88.4 % PO4-P removal compared to the SPBRs with 41.1 %−82.0 % NH4-N and 39.6 %−72.9 % PO4-P removal. MPBRs enhanced more nutrient utilization (24.9–49.3 g(N)/(m3·d) and 3.4–8.1 g(P)/(m3·d)) and CO2 assimilation (22.9–43.4 g(C)/(m3·d)), and concentrated more microalgae with 1.58–1.98 g/L higher than the SPBRs. Moreover, the MPBR effectively upgraded the biogas from AnMBR with superior methane percentage of 89.4 %−93.4 % due to its better CO2 biofixation. The MPBR, with better carbon, nitrogen and phosphorous removal and bioenergy production, following AnMBR is an attractive decarbonized technology for future sustainable wastewater treatment.

Ammonium removal and recovery from effluent of AnMBR treating real domestic wastewater using polymeric hydrogel

Anaerobic membrane bioreactor (AnMBR) technology has been considered promising to transform domestic wastewater (DWW) treatment as a net energy producer via bioenergy recovery. However, ammonium-nitrogen (NH4+-N) in DWW cannot be removed by anaerobic process, which raises the risk of eutrophication and prevents the wide-scale adoption of AnMBRs. This study proposed adsorption/desorption by poly (acrylic acid) (PAA) hydrogel as the post-treatment of AnMBRs to remove and recover NH4+-N, thus simultaneously promoting AnMBR technology and the circular economy. Batch experiment results showed that NH4+-N could be rapidly adsorbed by PAA hydrogels within 30 min with excellent maximum adsorption capacities of 110.6–120.8 mg N/L (10–50 °C). Furthermore, PAA hydrogels retained 81.1 % of NH4+-N adsorption capacity when treating AnMBR effluent, preliminarily suggesting their practical feasibility in complex water matrix. Thereafter, PAA hydrogels were packed into a bench-scale fixed-bed column. Up to 98.5% of NH4+-N in AnMBR effluent could be captured in the hydrogel column at the breakthrough point at flow rate of 0.5 mL/min, achieving a polished effluent concentration of <1.5 mg N/L and thus meeting the strictest discharge regulations. The hydrogel column could be regenerated for 10 adsorption/desorption cycles with an insignificant decline in adsorption capacity of ∼4.7%, highlighting its excellent reusability. More importantly, we for the first time proposed the strategic recirculation of 1 mol/l HCl solution as eluent and obtained an NH4+-N enrichment factor of ∼10 over four rounds of adsorption/desorption, demonstrating the promise of this strategy to concentrate NH4+-N as resources. The economic analysis based on our experimental results showed that PAA hydrogel-based adsorption/desorption process coupled with eluent recirculation has the potential to remove and recover NH4+-N from AnMBR effluent cost-effectively. Overall, this study could potentially expand the application of AnMBRs and foster innovations in sustainable wastewater treatment.

Submerged hollow-fiber-ultrafiltration for harvesting microalgae used for bioremediation of a secondary wastewater

Microalgae were employed to remove nutrients from a pre-treated wastewater (so-called anaerobic membrane bioreactor effluent, AnMBR effluent) over a 24-day semi-continuous cultivation with varied N:P ratios. NH4+-N reduction percentage ranged from 68 to 94% with average removal rates varying from 8 to 26mgN·L-1d-1 at different stages. Total phosphorus was almost completely removed shortly after inoculation. Biomass productivity ranged from 0.13 to 0.19 g·L-1d-1 during the cultivation. A submerged membrane-based filtration device was used to investigate the formation of biofouling, which occurred on the membrane surface during filtration and is considered as a bottleneck in downstream processing. Results indicated most severe fouling was caused by original microalgal suspension, compared to its individual fractions (cellular resuspensions, supernatant and AnMBR effluent). Irreversible fouling mainly occurred at the beginning of the filtration process; extracellular organic matter and cellular debris in the supernatant changed the fouling behavior more significantly than morphological properties of the algae cells; AnMBR effluent also led to a nonnegligible fouling effect. To minimize biofouling, TOC content in wastewater should be carefully controlled before and during cultivation. The current membrane can be proposed for long-term filtration, as irreversible fouling only occurred at the beginning and reversible fouling can be controlled effectively by backflushing and aeration. The biomass, characterized by relatively high protein and carbohydrate but low heavy metal content, indicated its potential as feeds and feedstock for bioenergy production. The present work provides novel insights into the coupling of wastewater treatment and fouling control, which has been rarely studied.

Targeted pressure-based development of membrane biofilms improves anaerobic membrane bioreactor effluent quality

Membrane biofilms were predeveloped at different transmembrane pressure and flux combinations in an AnMBR to promote better effluent quality and enhanced emerging contaminant removal.

Performance and mechanism of in-situ biogas upgrading using anaerobic membrane bioreactor effluent

Anaerobic membrane bioreactor (AnMBR) is considered an important alternative biogas source while efficiently purifying sewage. Improving the methane (CH4) content in the AnMBR biogas in a cost-effective way is closely related to its future availability. In the study, a novel system was proposed for in-situ biogas upgrading using AnMBR effluent. The system achieves the dual goals of bioenergy recovery from sewage and biogas upgrading. Biogas upgrading results showed that the CH4 content in upgraded biogas was 90.3% at biogas flow of 0.36 L/h, effluent flow of 2.88 L/h, and normal temperature and pressure. The mechanism analysis showed that efficient upgrading with AnMBR effluent depended on sufficiency alkali products and less N2 and O2. Meanwhile, conversion efficiency of chemical oxygen demand (COD) to CH4 of AnMBR was 78.5% under hydraulic retention time (HRT) of 8 h and organic load rate of 1.2 g COD/L/d. The novel system provides a new solution for cost-effective in-situ biogas upgrading using AnMBR effluent by integration of AnMBR with scrubbing column.

Tailoring Non-conventional Water Resources for Sustainable and Safe Reuse in Agriculture

In water scarce areas, like the Mediterranean Region where the lack of irrigation water is already limiting agricultural production, the valorization of non-concventional water resources is utmost important. Accordingly, in this study, we aimed to provide safe and locally sustainable ways of water supply for the Mediterranean agricultural sector by exploiting non-conventional water resources for irrigation purpose. In this context, pilot scale anaerobic reactors treating urban wastewater were operated coupling upflow anaerobic sludge blanket (UASB) reactor and ultrafiltration anaerobic membrane bioreactor (AnMBR). The resulting permeate is of high quality, accomplishing the EU quality standards for irrigation water reuse, also in terms of E.coli as the main microbial indicator. However, contaminants of emerging concern (CECs) can be a further limitation for safe reuse of the reclaimed water. Hence, molecularly imprinted polymers (MIPs) were further integrated as the final refining step for the selective removal of CECs. Diclofenac was used as the target compound with a removal efficiency up to 50% in the final effluent. In parallel, an intensive pilot system was operated for brine treatment through evaporation, chemical addition and precipitation, and forward osmosis, where up to 77% Mg2+ and 45% Ca2+ recovery rates were achieved. The recovered Mg-salts from the brine treatment were then used as an external source to enhance the struvite precipitation in the N- and P-rich effluent of AnMBR. The preliminary tests showed that only hydroxiapatite salts precipitated without any external P addition.

A focused review on membrane contactors for the recovery of dissolved methane from anaerobic membrane bioreactor (AnMBR) effluents

The need for a more sustainable wastewater treatment is more relevant now due to climate change. Production and reuse of methane from anaerobic treatment is one pathway. However, this is defeated by the presence of dissolved methane in the effluent and would be released to the environment, adding to the greenhouse gas emissions. This review paper provided summary and analysis of studies involved in the production of dissolved methane from AnMBR, focusing with actual methane measurement (gas and dissolved) from AnMBR with different types of wastewater. Then more focused discussion and analysis on the use of membrane-based technology or membrane contactors in the recovery of dissolved methane from AnMBR effluent are included, with its development and energy analysis. The dissolved methane removal and recovery rate of membrane contactors can be as high as 96% and 0.05 mol methane/m2/h, respectively, with very low additional energy requirement of 0.01 kWh/m3 for the recovery. Future perspectives presented focus on the long-term evaluation and modelling of membrane contactors and on the membrane modifications to improve the selectivity of membranes to methane and to limit their fouling and wetting, thus making the technology more economical for resource recovery.

Advanced near-zero waste treatment of food processing wastewater with water, carbon, and nutrient recovery.

A near-zero waste treatment system for food processing wastewater was developed and studied. The wastewater was treated using an anaerobic membrane bioreactor (AnMBR), polished using an outdoor photobioreactor for microalgae cultivation (three species were studied), and excess sludge was treated using hydrothermal carbonization. The study was conducted under arid climate conditions for one year (four seasons). The AnMBR reduced the total organic carbon by 97%, which was mostly recovered as methane (~57%) and hydrochar (~4%). Microalgal biomass productivity in the AnMBR effluent ranged from 0.25 to 0.8g·L-1·day-1. Nitrogen (N) and phosphorous (P) uptake varied seasonally, from 18 to 45mg·L-1·day-1 and up to 5mg·L-1·day-1, respectively. N and P mass balance analysis demonstrated that the process was highly efficient in the recovery of nitrogen (~77%), and phosphorus (~91%). The performance of the microalgal culture changed among seasons because of climatic variation, as a result of variation in the wastewater chemistry, and possibly due to differences among the microalgal species. Effluent standards for irrigation use were met throughout the year and were achieved within two days in summer and 4.5days in winter. Overall, the study demonstrated a near-zero waste discharge system capable of producing high-quality effluent, achieving nutrient and carbon recovery into microalgae biomass, and energy production as biogas and hydrochar.

Control of sulfides and coliphage MS2 using hydrogen peroxide and UV disinfection for non-potable reuse of pilot-scale anaerobic membrane bioreactor effluent

Anaerobic membrane bioreactors reduce the energy cost of wastewater treatment and meet filtration requirements for non-potable reuse. However, sulfides (H2S/HS−) formed during anaerobic treatment exert a high chlorine demand and inhibit UV disinfection by photon shielding at 254 nm. This study evaluated the feasibility of hydrogen peroxide (H2O2) for sulfide oxidation, UV disinfection for inactivation of MS2 bacteriophage, and chlorine to provide a residual for distribution. H2O2 treatment at pH ≥ 8 favored sulfide oxidation to sulfate in 30 min at a 4:1 H2O2:sulfide stoichiometry. Compared to a 6:1 H2O2:sulfide molar ratio, treatment of anaerobic effluent with 0.5 mM sulfides with a 4:1 H2O2:sulfide molar ratio would increase the applied UV fluence needed for 5-log MS2 inactivation from 180 mJ cm−2 to 225 mJ cm−2. However, the lower H2O2 dose reduced the dose of chlorine needed to quench residual H2O2 and provide a residual for distribution. Treatment at the 4:1 H2O2:sulfide molar ratio was favored, because the cost savings in H2O2 and chlorine reagents outweighed the energy savings associated with UV treatment. However, H2O2/UV/chlorine treatment of anaerobic effluent was cost-competitive with conventional treatment of aerobic effluent for non-potable reuse only for < 285 µM sulfides.

Optimization of reverse osmosis operational conditions to maximize ammonia removal from the effluent of an anaerobic membrane bioreactor

RO enables the recovery of clean water and ammonium in anaerobic membrane bioreactor effluent. pH governs the ammonia speciation and membrane surface charge and is the key operational factor that affects the total ammonia rejection efficiency of RO.

The use of UV/H2O2 to facilitate removal of emerging contaminants in anaerobic membrane bioreactor effluents

Effluent from anaerobic membrane bioreactor (AnMBR) contains ammonia and would require post-polishing treatment before it can be disinfected by chlorine. However, additional post-treatment steps to remove nutrients offset the energetic benefits derived from anaerobic fermentation. The use of chlorine or ozone also promotes concerns associated with disinfection byproducts. This study evaluates UV/H2O2 as a potential strategy suited for the removal of pharmaceutical compounds as well as antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from AnMBR effluent. Our findings indicate that 10 mg/L H2O2 and 61.5 mJ/cm2 of UV fluence are able to achieve a 4-log removal of both Escherichia coli PI7 and Klebsiella pneumoniae L7. However, a higher fluence of 311 mJ/cm2 with the same amount of H2O2 would be required to achieve >90% removal of atenolol, carbamazepine and estrone. The removal of the pharmaceutical compounds was driven by the hydroxyl radicals generated from H2O2, while UV exposure governed the inactivation of ARB and ARGs. UV/H2O2 increased overall mutagenicity of the treated wastewater matrix but did not result in any changes to the natural transformation rates. Instead, UV significantly reduced natural transformation rates by means of DNA damage. Overall, UV/H2O2 could be the ideal final disinfection strategy for AnMBR effluent without requiring additional post-treatment prior disinfection.

An innovative anaerobic MBR-reverse osmosis-ion exchange process for energy-efficient reclamation of municipal wastewater to NEWater-like product water

The rapid population growth and urbanization have led to an increasing need on recycle and reuse of municipal wastewater. In the current practice for high-grade reclaimed water production, municipal wastewater was first treated by conventional biological process, and further purified through microfiltration and reverse osmosis. However, such a multi-stage process has received more and more critiques due to the process complexity, intensive energy consumption, excessive sludge production and large footprint. To address these emerging issues, this study evaluated the feasibility of an innovative integrated anaerobic membrane bioreactor (AnMBR)-reverse osmosis (RO)-ion exchange (IE) process for treatment of municipal wastewater to high-grade reclaimed water with high energy efficiency and minimized waste sludge production. In this integrated process, an AnMBR was employed as the lead for energy recovery through direct COD capture, and AnMBR effluent was subsequently reclaimed to NEWater-like product water through combined RO and IE. Results showed that nearly 76.8% of influent COD was converted to methane in AnMBR equivalent to 0.41 kWh/m3 wastewater treated, while more than 95% of organic carbon, ammonium, phosphate, major ions and cations in AnMBR effluent were rejected by RO. After further polishing by IE, the product water quality appeared to be comparable or even better than the typical NEWater quality in Singapore. This study showed that the integrated AnMBR-RO-IE process could produce NEWater-like product water with compact footprint, near-zero sludge production, high operation stability, maximized energy recovery and reduced energy consumption compared to the current process for NEWater production from municipal wastewater. It is expected that the proposed process can offer new insights into the direction of future wastewater reclamation.

PDMS-coated porous PVDF hollow fiber membranes for efficient recovery of dissolved biomethane from anaerobic effluents

This report demonstrates the fabrication of a composite hollow fiber membrane that efficiently recovers dissolved methane (dCH4) from anaerobic wastewater treatment effluents via membrane contactor (MC) process. We first fabricated highly porous hollow fiber membranes (∼85% porosity) using polyvinylidene difluoride (PVDF). Then, we coated the whole structure (bulk), or lumen side of PVDF supports with polydimethylsiloxane (PDMS), a hydrophobic polymer possessing high gas permeability. The adjustment of the concentration of PDMS precursor mix could effectively serve for tuning the performance characteristics of MC membranes and helped suppress membrane wetting, a major performance-reducing factor. Despite their denser skin layers, the lumen-modified membranes demonstrated superior dCH4 recovery flux. Mass transfer analyses have confirmed the importance of preserving bulk porosity while coating the membrane surfaces. The long-term performance tests performed using actual anaerobic effluents suggested that the PDMS coating did not accelerate fouling, such that the lumen-modified MC membranes showed an almost steady flux for 8 days with an anaerobic membrane bioreactor effluent. A high-strength effluent, obtained from an up-flow anaerobic sludge blanket reactor, induced faster fouling. However, we observed only a ∼20% flux decline in a 10-day operation. Thus, we propose that the designed PDMS-PVDF composite membranes are promising for industrial practices.