印染废水处理过程中有机污染物及急性毒性变化规律研究

我国印染废水排放量大,对于印染废水中典型毒害物质的控制日趋严格,且生物毒性控制越来越受到重视.因此,本文以掌握典型印染废水处理中污染物去除特性和毒性转化机制为目标,解析印染废水水质特征及其在典型处理工艺中的变化.结果发现,典型印染废水处理工艺对典型污染物的去除效率较好,出水COD、苯胺浓度、色度分别为46 mg·L~(-1)、0.86 mg·L~(-1)、6倍,去除效率分别为78%、95%、86%;但对急性毒性的控制不足,尤其是有机组分的急性毒性控制不足.典型印染废水处理中,生物曝气处理是控制典型污染物的主要阶段,对COD、色度、苯胺的去除效率分别达60%、23%、50%,对生物毒性的去除率为48%.氯氧化和混凝沉淀是保障印染废水中苯胺类有毒物质和色度达到排放标准的重要深度处理阶段,对色度、苯胺的去除效率分别为86%、95%;然而,深度处理却会引发印染废水急性毒性急剧升高,升高比例达150%.印染废水中的急性毒性组分包括有机组分和无机组分,生物曝气主要去除有机组分毒性;氯化深度处理会增加有机组分毒性和无机组分毒性,其中,无机组分毒性可通过还原脱氯削减,但有机组分毒性控制需综合考虑前处理阶段提质增效或实施氯氧化替代工艺.

Study on the removal of organic pollutants and acute toxicity variation in the process of dyeing wastewater treatment

The control of typical poisonous substances in dyeing wastewater is becoming more and more strict, especially for biological toxicity. The present study collected the influent and effluent of each treatment unit in typical dyeing wastewater treatment plants in Suzhou. It is found that the typical dyeing wastewater treatment has good removal efficiency for typical pollutants. The average concentration of COD, aniline and colority in effluent were 46 mg·L^-1, 0.86 mg·L^-1, 6 times, with the removal efficiency 78%, 95%, 86%, respectively. However, the control of acute toxicity was insufficient, especially for the acute toxicity of organic components. The biological aeration treatment is the main stage to control pollutants in typical dyeing wastewater treatment process. The removal efficiency of COD, colority, aniline and biotoxicity were 60%, 23%, 50% and 48%, respectively. Chlorine oxidation and coagulation sedimentation are important post processing stages to ensure the effective removal of toxic substances and colority. The removal efficiency of aniline and color were 95% and 86%. However, the advanced oxidation increased the acute toxicity by 150%. The acute toxic components in dyeing wastewater included organic components and inorganic components. Biological aeration process mainly removed the toxicity of organic components. Advanced treatment of chlorination increased the toxicity of organic and inorganic components. The toxicity of inorganic components can be reduced by reductive dechlorination. However, the toxicity control of organic components needs to comprehensively consider the quality improvement of pretreatment stage or the implementation of alternative approaches to replace chlorine oxidation.