A/DAT-IAT工艺处理城市污水的生态安全调控

以A/DAT-IAT工艺出水的常规指标和生态毒性指标为考察对象，对A/DAT-IAT工艺处理城市污水的运行周期（T）、外回流比（R₁）、内回流比（R₂）和混合液污泥浓度（MLSS）4个控制参数进行了3个水平的正交试验.结果表明：混合液污泥浓度（MLSS）是4个控制参数中对考察对象影响最大的因素；去除常规指标的最优运行条件为运行周期3 h，外回流比20%，内回流比150%，MLSS 5000 mg·L^-1；去除生态毒性指标的最优运行条件为运行周期3 h，外回流比20%，内回流比150%，MLSS 3000 mg·L^-1.分析表明，造成去除两类指标的最优运行条件不同的主要原因可能是污水中存在具有一定生态毒性的难生物降解有机物和经水解酸化后毒性增强的有机物.本试验研究为该工艺今后的生态安全调控改进提供了参考方向.建议投加絮凝剂，同时适当选择运行控制参数，以共同提高对常规指标和生态毒性指标的去除效果.

Ecological safety regulation of A/DAT-IAT process for municipal wastewater treatment.

Four controlling parameters of A/DAT-IAT process for municipal wastewater treatment, i.e., operation period (T), external recycled rate (R1), internal recycled rate (R2), and mixed liquid suspended solid concentration (MLSS), were studied by orthogonal experiments, and the regular and ecotoxicological indicators of the effluents were examined. The results showed that the optimum conditions of regular indicators removal were T=3 h, R1=20%，R2=150%, and MLSS=5000 mg·L-1, and the optimum conditions of ecotoxicological indicators removal were T=3 h, R1=20%，R2=150%, and MLSS=3000 mg·L-1. The reason which caused the difference of the two optimum conditions might be that there were some non-biodegradable organic matters having certain ecological toxic effects and some organic matters whose ecological toxicity increased after hydrolysis and acidification. Adding flocculants and properly choosing controlling parameters were suggested to improve the regular and ecotoxicological indicators of the effluent.