Nitrogen removal by submerged membrane separation activated sludge process

The performance of the submerged membrane separation activated sludge (SMAS) process with intermittent aeration was investigated in a laboratory scale experiment. By intermittent aeration (30 minutes cycle), nitrogen was removed successfully (95% removal rate) from influent containing NH4-N and acetic acid. A mathematical model was developed to simulate the performance of the SMAS considering the behavior of extracellular polymers (production, degradation, accumulation on the membrane and consolidation) and the experimental result was successfully simulated by the model. Degradation of EPS was accelerated by intermittent operation, which suggests that the combination of biological denitrification with the membrane separation process is advantageous in the prevention of membrane fouling in the BOD-removal-type membrane process. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.