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Sustainable municipal wastewater recovery scenarios highlight benefits of anaerobic membrane bioreactors (AnMBRs). However, influences of continuous seeding by influent wastewater and temperature on attached-growth AnMBRs are not well understood. In this study, four bench-scale AnMBR operated at 10 and 25 °C were fed synthetic (SPE) and then real (PE) primary effluent municipal wastewater. Illumina sequencing revealed different bacterial communities in each AnMBR in response to temperature and bioreactor configuration, whereas differences were not observed in archaeal communities. Activity assays revealed hydrogenotrophic methanogenesis was the dominant methanogenic pathway at 10 °C. The significant relative abundance of Methanosaeta at 10 °C concomitant with low acetoclastic methanogenic activity may indicate possible Methanosaeta-Geobacter direct interspecies electron transfer. When AnMBR feed was changed to PE, continual seeding with wastewater microbiota caused AnMBR microbial communities to shift, becoming more similar to PE microbiota. Therefore, influent wastewater microbiota, temperature and reactor configuration influenced the AnMBR microbial community.

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Anaerobic membrane bioreactors (AnMBR) play a key role in future plans for sustainable wastewater treatment and resource recovery because they have no energy-intensive oxygen transfer requirements and can produce biomethane for renewable energy. Recent research results show that they can meet relatively stringent discharge limits with respect to BOD 5 and TSS when treating municipal wastewater primary effluent. Sustainable used water recovery plans should also consider removal of unregulated pollutants. Antibiotic resistance genes (ARGs) represent an important emerging contaminant due to public health concerns surrounding the spread of infections resistant to common antibiotics. Conventional activated sludge processes have demonstrated mixed results regarding ARG removal. The objective of this research was to determine the impact of an AnMBR on ARG removal when treating municipal primary clarifier effluent at 20°C. AnMBR treatment resulted in 3.3 to 3.6 log reduction of ARG and the horizontal gene transfer determinate, intI1, copies in filtrate. Membrane treatment significantly decreased the total biomass as indicated by a decrease in 16S rRNA gene concentration. Microbial community analysis via Illumina sequencing revealed that the relative abundance of putative pathogens was higher in membrane filtrate compared to primary effluent although the overall bacterial 16S rRNA gene concentrations was lower in filtrate. Membrane treatment also substantially reduced microbial diversity in filtrate compared to anaerobic reactor contents.Mainstream anaerobic wastewater treatment is a promising technology for sustainable water resource recovery. Anaerobic membrane bioreactors (AnMBRs) can meet relatively stringent BOD 5 and TSS regulatory standards (BOD 5 <10 mg L −1 , TSS <10 mg L −1 ) for municipal wastewater at temperatures as low as 10°C. The research reported herein demonstrated that AnMBR technology can also significantly reduce antibiotic resistance gene copies.

Unique anaerobic membrane bioreactor system achieves high organic removal with low energy requirements.

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This work assessed if acid-phase digestion could improve volatile solids (VS) destruction and methane yield when co-digesting municipal sewage sludges (primary and waste activated sludge) and source separated organics (SSO). The SSO was made up of food waste and the organic fraction of municipal solid waste. Two laboratory-scale acid-phase digesters and three laboratory-scale methane-phase digesters were employed in order to determine the impacts of SSO co-digestion with municipal sludges both with and without acid-phase digestion as a pretreatment step. Reactors were operated at 35 °C using volatile solids loading rates of 34.2–44.1 g VS/LR-day for acid-phase digesters and 1.2–2.4 1 g VS/LR-day for methane-phase digesters. Solids retention times ranging from 1.2 to 1.5 day and 20.7 to 23.2 days were employed for acid-phase and methane-phase digesters, respectively. VS destruction ranged from 62% to 67%, with reactors receiving SSO achieving higher VS destruction. Results also show that reactors receiving SSO were able to handle organic loading increases of at least 39% without showing signs of overloading. Microbial community analysis revealed that SSO had a noticeable impact on acid-phase digestion with Megasphaera emerging as the most abundant genus.