Simultaneous phosphorus and nitrogen removal in a continuous-flow two-sludge system

Article type: Research Article

Authors: LI, Xiang-kun | HUANG, Rong-xin | BAO, Lin-lin | SHAO, Chun-hong | ZHANG, Jie

Affiliations: School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China

Note: [] Corresponding author. E-mail: [email protected]

Abstract: The ability of simultaneous biological phosphorus and nitrogen removal was investigated in a lab-scale continuous-flow two-sludge system. Alternating anaerobic and anoxic conditions were combined with contact oxidation stage for treating raw municipal wastewater. Long-term experiments showed that the contradiction of competing for the organic substrate between denitrifying bacteria and PAOs (phosphorus accumulating organisms) in traditional phosphorus and nitrogen removal system has been resolved. The system can adapt to low influent COD/TN ratio (C/N). Furthermore the SRT (sludge retention time) of nitrifying sludge and denitrifying phosphorus removal sludge can be controlled at optimal conditions respectively. The removal efficiency of COD, TP, TN, and NH_4-N was 81.78%, 92.51%, 75.75%, and 84.47% respectively. It was also found that the appropriate influent C/N should be controlled at the range of 3.8–6, while the optimal C/N to the system ranged between 4–5, and the BFR (bypass sludge flow rate) should be controlled at 0.35 around.

Keywords: continue-flow two-sludge system, denitriflcation phosphorus removal, nitrification, contact oxidation

Journal: Journal of Environmental Sciences, vol. 18, no. 1, pp. 52-57, 2006