Long‐term assessment of the effect of OLR , HRT and temperature on domestic sewage treatment using AnMBR to enhance biomethane production

Abstract The objective of this study was to evaluate the potential of an anaerobic membrane bioreactor (AnMBR) to treat domestic sewage by removing organic matter and nutrients while producing biogas. AnMBRs combine anaerobic digestion with membrane filtration, and stand out for their low energy consumption, low sludge production and potential for resource recovery. The 450‐day experiment divided into three phases, used domestic sewage as effluent, and evaluated factors such as pH (maintained between 6.4 and 7.0), temperature (21–35 °C), hydraulic retention time and organic load, which were monitored to optimize microbial performance and biogas production. The stability of the AnMBR was monitored by measuring chemical oxygen demand (COD), pH, nitrogen, phosphorus and total suspended solids (TSS). The AnMBR demonstrated robustness and stability in maintaining the quality of the permeate even under high variations of COD and biomass content. The results demonstrated high system efficiency, with organic matter removal exceeding 81% for COD and biochemical oxygen demand and over 94% for suspended solids. Biogas production varied between 0.25 and 0.37 m 3 CH 4 kg COD −1 , with an average methane composition ranging from 35 to 74%. In addition to meeting standards for water reuse or reclamation, the process proved to be promising given that COD and TSS removal efficiencies were achieved, reinforcing its contribution to the sustainable management of resources.