[Treatment of phenol wastewater by extractive membrane bioreactor]

Phenol-degrading bacteria were isolated from activated sludge which had been acclimated, and then bacterium solution was prepared. The effects of initiating phenol concentration, reactor temperature etc. and the velocity of membrane extraction and biodegradation were investigated in order to make the comparison of activated sludge and bacterium solution systems of extractive membrane bioreactor (EMB). The results showed that, by using phenol as single carbon resource and increasing the phenol concentration gradually, the removal rate of phenol was more than 99% when the concentration of phenol was 700 mg x L(-1). Increasing reactor temperature and initiating phenol concentration is propitious to the membrane extraction. There was some phenol accumulation in microbial system when the initiating concentration was 2000 mg x L(-1). The thickness of the membrane-attached biofilm in the bacterium solution system was thinner than that in activated sludge system, and it could be controlled by hydrodynamic backwashing. The results of GC-MS analysis for the effluent of biodegradation showed that biodegradation of phenol was complete, and there was no residual intermediate product.