城市污水石灰法深度处理工艺中有毒物质的变化规律

分别采用7-乙氧基异酚恶唑酮-脱乙基酶(EROD)活性测定法,重组人激素受体基因的酵母测试和Q67发光菌试验方法,对北京市某生活污水处理厂的进水、二沉出水以及经过石灰法深度处理后的出水中的类二恶英物质、类雌激素物质和急性毒性物质进行了分析.进水中的三类生物毒性效应物质中的急性毒性物质,可通过活性污泥法基本去除,而对类雌激素物质和类二恶英物质的去除率分别为76%和52%.经过石灰沉淀法的深度处理后,可使上述两类物质的总去除率达到95%和68%.出水中的雌激素当量水平与欧洲国家污水处理厂出水水平相当,而类二恶英物质的总浓度低于美国EPA饮用水中二恶英的最大允许浓度.展示了生物毒性测试方法在排水生态风险和工艺评价方面的应用潜力.

Change law of toxicants in municipal wastewater treated with lime precipitation

The matters with estrogenic effect,dioxin-like effect and acute toxicity in the influent,and effluents from secondary treatment,as well as effluents from the consequential lime treatment were evaluated by using recombinant yeast assay,7-Ethoxyresorufin-O-Diehthylase(EROD) assay and the photobacterium luminescent assay,respectively.Most of the acute toxic pollutants in the influent could be removed,while 76% of the estrogenic effect pollutants and 52 %dioxin-like pollutants were eliminated by the biological process based on active sludge.After an advanced treatment using lime precipitation,95% of estrogenic-effect chemicals and 68 % of dioxin-like chemicals in the influent could be removed,respectively.Level of estrogenic effect chemicals in the final effluent was in the same order of magnitude as compared to those in European countries,while level of dioxin-like chemicals was as low as the Maximum Contaminant Level for Drinking Water issued by the USEPA.We concluded that the application of the battery of in vitro bioassays could provide screening information on the feasibility of different wastewater treatment processes and potential impact of effluent discharge on receiving waters.