The innovative process consists of biol. unit for wastewater treatment and ozonation unit for excess sludge treatment.An aerobic membrane bioreactor (MBR) was used to remove organics and N, and an anaerobic reactor was added to the biol. unit for the release of P contained at aerobic sludge to enhance the removal of P.For the excess sludge produced in the MBR, which was fed to ozone contact column and reacted with ozone, then the ozonated sludge was returned to the MBR for further biol. treatment.This process could remove organics, N, and P efficiently, and the removals for COD, NH3-N, TN and TP were 93.17, 97.57, 82.77, and 79.5%, resp.Batch test indicated that the specific nitrification rate and specific denitrification rate of the MBR were 1.03 mg NH3-N/(g MLSS·h) and 0.56 mg NOx-N/(g MLSS·h), and denitrification seems to be the rate-limiting step.Under the test conditions, the sludge concentration in the MBR was kept at 5000-6000 mg/L, and the wasted sludge was ozonated at an ozone dosage of 0.10 kg O3/kg SS.During the exptl. period of 2 mo, no excess sludge was wasted, and a zero withdrawal of excess sludge was implemented.