Man-Hong Huang1, Yong-Mei Li, Guo-Wei Gu. 1. State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Abstract
OBJECTIVE: This study was conducted to optimize the operational parameters of anaerobic-anoxic-oxic (A²/O) processes to reduce the toxicity of municipal wastewater and evaluate its ability to reduce toxicity. METHODS: A luminescent bacterium toxicity bioassay was employed to assess the toxicity of influent and effluent of each reactor in the A²/O system. RESULTS: The optimum operational parameters for toxicity reduction were as follows: anaerobic hydraulic retention time (HRT) = 2.8 h, anoxic HRT = 2.8 h, aerobic HRT = 6.9 h, sludge retention time (SRT) = 15 days and internal recycle ratio (IRR) = 100%. An important toxicity reduction (%) was observed in the optimized A²/O process, even when the toluene concentration of the influent was 120.7 mg·L⁻¹. CONCLUSIONS: The toxicity of municipal wastewater was reduced significantly during the A²/O process. A²/O process can be used for toxicity reduction of municipal wastewater under toxic-shock loading.
OBJECTIVE: This study was conducted to optimize the operational parameters of anaerobic-anoxic-oxic (A²/O) processes to reduce the toxicity of municipal wastewater and evaluate its ability to reduce toxicity. METHODS: A luminescent bacterium toxicity bioassay was employed to assess the toxicity of influent and effluent of each reactor in the A²/O system. RESULTS: The optimum operational parameters for toxicity reduction were as follows: anaerobic hydraulic retention time (HRT) = 2.8 h, anoxic HRT = 2.8 h, aerobic HRT = 6.9 h, sludge retention time (SRT) = 15 days and internal recycle ratio (IRR) = 100%. An important toxicity reduction (%) was observed in the optimized A²/O process, even when the toluene concentration of the influent was 120.7 mg·L⁻¹. CONCLUSIONS: The toxicity of municipal wastewater was reduced significantly during the A²/O process. A²/O process can be used for toxicity reduction of municipal wastewater under toxic-shock loading.