[Effect of backwashing on dominant microorganism stabilization of BEAC filter controlled by the biological factors].

Six kinds of dominant microorganism used for the bioenhancement activated carbon(BEAC) filter were investigated for the study of backwashing effect on microorganism stabilization. The pilot plant results showed the average biomass loss was 15.47% when only water backwashing invited during the start-up period and air-water scour backwashing invited during stabilization operation period. The optimal backwashing parameters were determined by the biological factor of biomass respiration potential (BRP). The optimal air flow rate for the BEAC filter was 8-10 L/(m2 x s) under which conditions the biomass and biological activity of the dominant microorganism had the minimum variation before and after backwashing. The SEM and PCR-DGGE photos showed that the biomass of dominant microorganism after air-water scour backwashing decreased during start-up period and retained stability during stabilization operation period.