Deep insights into the anaerobic co-digestion of waste activated sludge with concentrated leachate under different salinity stresses

Treatment of high-salinity organic wastewater (e.g., concentrated leachate) is a major challenge. Anaerobic co-digestion can effectively treat high-salinity organic wastewater and recover energy. In this study, the concentrated landfill leachate and waste activated sludge (WAS) were anaerobic co-digested in the lab-scale continuous stirred tank reactors (CSTR) to understand their co-digestion performance under different salinity stresses. As revealed by the results, when the salinity was low (91.3%), and the concentration of total volatile fatty acids (TVFAs) was low (