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 remo
ved successfully (95% removal rate) from influent containing NH4-N and acet
ic acid. A mathematical model was developed to simulate the performance of
the SMAS considering the behavior of extracellular polymers (production, de
gradation, accumulation on the membrane and consolidation) and the experime
ntal 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 adva
ntageous in the prevention of membrane fouling in the BOD-removal-type memb
rane process. (C) 1999 Published by Elsevier Science Ltd on behalf of the I
AWQ. All rights reserved.