LAUSR

Abstract Wastewater samples from 267 rural domestic wastewater treatment systems in Yangtze River Delta region were collected and analyzed to investigate their treatment performance and identify potential problems. The influent wastewater was mainly affected by the treatment performance of septic tanks, the combined rainwater and wastewater collection, and the pipeline damage. Seven kinds of treatment processes were employed in the studied treatment systems, with constructed wetlands (CWs) being the main process accounting for 66% of all the systems. CWs had the best performance on NH4+-N and chemical oxygen demand removal, anaerobic/oxic (AO)-CWs had the best performance on total nitrogen and total phosphorus removal, and membrane biofilm reactors had the best performance on suspended solids removal. To improve treatment performance, recirculation and aeration are recommended for CWs, while AAO and AO should be combined with CWs. Training to gain more professional skills for the operation staff is needed.