The feasibility of using a single sequencing batch reactor to remove nitrogen from medium-age landfill leachate was examined

and an anaerobic/aerobic/anoxic process in a SBR without extra carbon source addition was presented. Dissolved organic matter could be taken up partially and stored as polyhydroxyalkanoates (PHAs) in the anaerobic stage by the microorganisms operated in the anaerobic/aerobic/anoxic process

with glycogen consumption. In the aerobic stage

ammonia was oxidized and accompanied by loss of tatal nitrogen (TN) via simultaneous nitrification and denitrification. The stored PHAs and glycogen

remaining at the end of aerobic stage could provide carbon source for anoxic denitrification. In the stable phase

the effluent COD

NH4+-N

and TN were 525—943 mg·L-1

1.2—4.2 mg·L-1 and 18.9—38.9 mg·L-1 respectively when the influent COD

NH4+-N

and TN were 6430—9372 mg·L-1

1025.6—1327 mg·L-1 and 1345.7—1853.9 mg·L-1

respectively. Nitrogen removal from medium-age landfill leachate could be realized via the anaerobic/aerobic/anoxic process in a SBR with the effluent of TN less than 40 mg·L-1. Almost 1/3 of reduced TN was removed via SND

while 2/3 of reduced TN was removed via post-anoxic denitrification.