| Bioaugmentation treatment of atrazine by genetically engineered microorganism (GEM) in membrane bioreactor (MBR) and conventional activated sludge bioreactor (CAS), was investigated using domestic wastewater as co-substrate, and effects of bioaugmentation treatment on sludge activities were also discussed. The results showed that significant removal of atrazine was obtained in MBR with bioaugmentation: average atrazine concentration in effluent was 0.84 mg/L, average removal rate was 95%, and the maximum removal loading of atrazine was as high as 70 mg/(L·d). Average COD removal in MBR was 71%, and average COD concentration in effluent was 65 mg/L. However, COD removal was affected when volumetric loading of COD increased. NH3-N removal in MBR was also perfect: average NH3-N concentration in effluent was 1.1 mg/L, average removal rate was 97%, and the maximum removal loading of NH3-N was 143 mg/(L·d). Compared with sludge in common MBR, abilities of nitrification and nitrozation of sludge in bioaugmented MBR were higher but ability of carbon oxidation was lower, which was responsible for performance of COD and NH3-N removal probably. Exposure to atrazine resulted in some negative effects on activated sludge and might be the reason for lower carbon oxidation ability of bioaugmented sludge. |
