Anaerobic　treatment　is　the　most　widely　used　method　of　waste　activated　sludge　(WAS)　stabilization.　Using　a　semi-continuous　stirring　tank　with　condensed　WAS,　we　investigated　effects　of　decreasing　the　solid　retention　time　(SRT)　from　32　days　to　6.4　days　on　sludge　reduction,　soluble　chemical　oxygen　demand　(SCOD)　release　and　dehydration　capability,　along　with　anaerobic　digestion　operated　at　medium　temperature　(MT-AD)　or　anaerobic　digestion　operated　at　room　temperature　(RT-AD).　Results　showed　that　effects　of　temperature　on　SCOD　release　were　greater　at　SRT　of　32　d　and　6.4　d.　When　SRT　was　less　than　8　d,　total　solids　(TS),　volatile　solids　(VS)　and　capillary　suction　time　(CST)　did　not　change　significantly.　CST　was　lowest　at　SRT　of　10.7　days,　indicating　best　condition　for　sludge　dehydration.　Principal　component　analysis　(PCA)　showed　that　the　most　optimum　SRT　was　higher　than　10.7　d　both　in　MT-AD　or　RT-AD.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.