Fouling characteristics were observed through continuous operation of pilot-scale submerged membrane bioreactor (SMBR) for 120days. Flux decline ratio (J/Jo) changed with suction pressure, backwash cycle. Fouling decreased effectively and flux increased practically when the reactor operated on suction at 300mmHg for 5 minutes followed by backwash for 1 minute. MLSS and SS of influent affected fouling characteristics so much. In particular, SS of influent such as cellulose material, hair and red pepper powder caused most of resistance in the beginning of operation, attaching the surface of membrane and blocking the pores. Therefore pretreatment are required to depreciate fouling caused by SS. It was thought that SMBR was stable to high and shock loading, because the removal efficiencies of COD and SS were kept to 97% and 100% in the case that influent characteristics changed irregularly.
To know the cause of fouling under selected operating conditions, resistance induced by MLSS and ECP was measured using the stirred cell membrane. It was found that the cake resistance by ECP was a major part in total resistance by MLSS and the ratio of protein to carbohydrate in ECP was also important factor to increase the cake resistance.
The prediction of flux and cleaning cycle was performed using resistance-in-series model and mass balance equation. ECP concentration at the begining of continuous operation was the most important parameter in order to enhance the flux at steady state.
