城市污水再生处理工艺中发光细菌毒性变化的初步研究

保障再生水的生态安全是污水再生利用过程中非常关键的问题.本文采用发光细菌毒性测试方法测定了2个城市污水再生利用示范工程工艺流程中生物毒性的变化,尤其是可能生成有毒副产物的氯消毒过程中的毒性变化.结果表明,二级生物处理能显著降低污水的发光细菌毒性,但氯消毒显著提高了污水的毒性,并且脱氯后污水的毒性仍保持较高的水平,对生态安全造成了潜在威胁.同时,通过比较2种污水水质发现,DOC(溶解性有机碳含量)和UV254(254 nm处的紫外吸收值)较高的水样,消毒后的毒性较大,认为DOC和UV254可望作为预测污水消毒生态风险的水质指标,为污水消毒实践中确定安全合理的污水水质条件提供一定的依据.

Change of sewage toxicity on photo-bacteria during its treating process for water recycling

It has become a prevailing trend to recycle and reuse of wastewater in China to relieve water shortage. However, the ecological safety of recycled water is of primary concern both for the regulatory authorities and the ordinary users. This paper aims to introduce the author's study on how to change such toxicity for reuse. Using photo-bacteria bioassay, our experiment results show that two-stage biological treatment can evidently reduce the toxicity on photobacteria of the wastewater, though the chlorine disinfection can increase the toxicity of the wastewater remarkably. Even after dechlorination, the toxicity of the wastewater still remains high thus, having potentially endangered the ecological safety. At the same time, through comparing the water quality of the wastewater from the two treating processes, it is found that the water samples with higher DOC (dissolved organic carbon) or UV_ 254 (UV absorbance at 254 nm) would form higher toxicity after chlorine disinfection, thus DOC and UV_ 254 can be an important water-quality index to predict the disinfection risk and to guarantee the safety of the reused sewage during disinfection process.