Nutrient Removal from Municipal Wastewater in a Pilot-scale Plant with A²/O Process Operated at Low SRT by Ex-situ Bioaugmentation

Dang Cong Peng, Qiong Wan, Yun Han, Liying Pei, Jilin Wei, Zhengfu Wang, Sheping Wang, Hongfang Sun

 

ABSTRACT

Enhancing nutrient removal from municipal wastewater by bioaugmentation was investigated in a pilot plant operated in A2/O process. Reject water from sludge treatment was used as a feed for ex-situ cultivation of nitrifier-contained activated sludge in a new process named RAO for bioaugmentation. The experimental results showed that ex-situ bioaugmentation was very effective for enhancing nutrient removal. Ammonium and phosphorous concentrations in the effluent in mainstream could be reduced to less than 1mg/L at a HRT of 10h and SRT of 8d. FISH test proved that nitrifier community of activated sludge in side-stream was identical to that in mainstream, which resulted in little nitrification loss during bioaugmentation.


Keywords:Municipal wastewater; nutrient removal; activated sludge; reject water; bioaugmentation

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doi:10.11912/jws.2.3.159-166