Toxicity reduction of municipal wastewater by anaerobic-anoxic-oxic process / 生物医学与环境科学（英文）

ABSTRACT

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>A luminescent bacterium toxicity bioassay was employed to assess the toxicity of influent and effluent of each reactor in the A²/O system.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>