厌氧-缺氧-好氧处理工艺的污水处理厂进出水的毒性评价

为了准确评估厌氧-缺氧-好氧(A²/O)处理工艺对废水毒性的削减效率,采用斑马鱼胚胎急性毒性实验、发光细菌急性毒性实验和小鼠L929细胞毒性实验进行测试,结合理化指标,通过毒性当量(TU)法、平均毒性(Av Tx)法、毒性指数(Tx Pr)法、最敏感测试(MST)法和潜在生态毒性效应(PEEP)法对常州市6家污水处理厂(生活污水、综合废水、化工废水、制药废水)进水和出水的生物毒性进行了评价。结果表明,斑马鱼胚胎的毒性敏感程度最高,3种受试生物的毒性评价结果具有较好的一致性。理化达标的污水处理厂出水仍存在一定的生物毒性效应,出水毒性较大的是综合污水处理厂,排入受纳水体后可能会对周围的生态环境产生潜在的生态风险。A²/O处理工艺对各污水处理厂进水的毒性削减较好,其中对制药废水的毒性削减最高,Av Tx、Tx Pr、MST和PEEP的毒性削减率分别为99.45%、99.64%、99.48%和69.66%。与Av Tx、Tx Pr、MST法相比,PEEP法能够更综合地评价废水毒性。

Toxicity Evaluation of Influent and Effluent from Wastewater Treatment Plant with Anaerobic-Anoxic-Oxic Treatment Process

The zebrafish embryo acute toxicity test,the luminescent bacteria acute toxicity test and the mouse L929 cytotoxicity test were used to accurately evaluate the toxic reduction by Anaerobic-Anoxic-Oxic (A²/O) treatment processes.Combined with physical and chemical indicators,toxicity unit (TU) method,average toxicity (AvTx) method,toxic print (TxPr) method,most sensitive test (MST) method and potential ecotoxic effects probe (PEEP) method were used to assess the biotoxicity of the influent and effluent of 6 wastewater treatment plants (domestic wastewater,integrated wastewater,chemical wastewater,pharmaceutical wastewater) in Changzhou.The results showed that the zebrafish embryo was the most sensitive species,and three tested organisms presented consistent.The effluent of wastewater treatment plants meeting the physical and chemical standards still had biological toxicity effects,and the most toxic effluent was from the comprehensive plant.It might cause potential ecological risks to the surrounding ecological environment after being discharged into the receiving water body.The results of AvTx,TxPr,MST and PEEP showed that the A²/O treatment process had the highest toxicity reduction in pharmaceutical wastewater,and the toxicity reduction rates of the four evaluation indexes were 99.45%,99.64%,99.48% and 69.66%,respectively.Compared with AvTx,TxPr and MST,PEEP could evaluate the toxicity of wastewater more comprehensively.