To　deal　with　the　problem　of　carbon　source　lacking　and　the　difficulties　of　waste　activated　sludge　(WAS)　disposal　in　wastewater　treatment　plant　(WWTP),　nitrite　was　added　into　WAS　fermentation　system　(NSF)　to　develop　a　new　way　to　accomplish　denitrification　and　WAS　reduction　simultaneously　in　this　paper,　and　the　effect　of　electron　acceptor　concentration　(200,　400,　600,　and　800　mg/L　nitrite)　on　denitrification　in　NSF　was　studied.　Experiment　results　showed　that　different　NO2--N　concentration　of　NSF　systems　presented　different　denitrification　ability,　the　best　denitrification　performance　was　found　in　400　mg/L,　and　it　was　investigated　that　the　nitrite　removal　amount　per　unit　of　volatile　suspended　solid　(VSS)　reduction　in　different　NSF　systems　was　presented　as　this　order:　400＞600＞200＞800　(mg/L),　with　values　of　0.66,　0.60,　0.46,　0.44　mg　NO2--N/mgVSS-reduction　respectively.　Furthermore,　there　was　no　volatile　fatty　acids　(VFAs)　accumulation　in　400mg/L　NO2--N　concentration　system,　while　different　level　of　accumulation　in　other　NO2--N　concentration　systems　was　found,　which　meant　denitrifiers　in　400mg/L　NSF　could　utilize　carbon　sources　much　better　than　that　of　others.　Additionally,　all　the　systems　showed　a　great　sludge　reduction　capacity,　with　more　than　40%　of　VSS　reduction.　©　2012　IEEE.