Digested sewage treatment using membrane-based process at different hydraulic retention times

► An AT/MBR system was used to treat raw domestic wastewater. ► Decreasing HRT was applied to assess reactor performance and microbial properties. ► Decreasing HRT had stronger impact on nitrogen removal than carbon removal. ► Biomass concentration and membrane resistance was both highest at HRT 2.5 h. ► Decreasing HRT led to significant variation in microbial community.