某石化废水的综合毒性评价及其处理工艺对毒性的削减规律研究

利用生物毒性测试对环境中的污染物进行生态风险评价,是目前风险评价中的研究热点。本研究以明亮发光杆菌(Photobacterium phosphoreum)、斜生栅藻(Scenedesmus obliquus)和大型溞(Daphina magna)为受试生物,对某石化厂废水的处理流程中5个主要单元出水的急性毒性进行了测试,分析了其急性毒性与理化指标间的相关性;同时,为了解不同处理单元毒性去除效果及主要毒性来源,结合毒性鉴别评价(toxicity identification evaluation,TIE)技术对各阶段出水的毒性削减及其主要致毒物质类别进行了分析。毒性测试结果表明,该废水处理厂对石化废水的毒性去除效果比较显著,其中进水对明亮发光杆菌、斜生栅藻和大型溞分别表现为中毒、高毒和剧毒,最终处理后出水的毒性分别为无急性毒、中毒和微毒,对毒性的去除效率分别为96.4%、74.3%和99.5%。TIE结果表明,石化废水中的主要致毒物质是非极性有机物和可滤型物质。本研究结果为石化废水的综合生物毒性评价提供了研究基础,为探讨废水生物毒性的去除提供了实例参考。

Comprehensive Toxicity Evaluation and the Effect of the Treatment Process on Toxicity Reduction of A Petrochemical Wastewater

In the field of environmental risk assessment, one issue is to apply biological toxicity tests to evaluate the potential risk of pollutants. In this study, we tested the acute toxicity of five effluents of petrochemical wastewater from industrial wastewater treatment processes, using Photobacterium phosphoreum, Scenedesmus obliquusas and Daphnia magna as test organisms, and the relationship between the acute toxicity and physicochemical parameters were analyzed. Meanwhile, to identify the toxicity source of wastewater samples, toxicity identification evaluation (TIE) technique was performed. Our results showed that the current wastewater treatment process could reduce the acute toxicity significantly. The raw influent presented acute toxicity, high acute toxicity and very high acute toxicity on Photobacterium phosphoreum, Scenedesmus obliquus and Daphnia magna, respectively; while the final effluent exhibited no acute toxicity, acute toxicity and slight acute toxicity, respectively, resulting in the toxicity removal efficiencies of 96.4%, 74.3% and 95.5%, respectively. TIE results suggested that the main toxicity substances were non-polar organic and filterable material. Our results provided a basis for the evaluation of the comprehensive toxicity of petrochemical wastewater, and an example for the removal of biological toxicity of wastewater.