城镇污水循环活性污泥处理系统中典型新烟碱类杀虫剂污染特征及去除特性

Pollution and removal of five neonicotinoid insecticides in a municipal wastewater treatment plant with cyclic activated sludge system

采用固相萃取-高分辨液相色谱-串联质谱(SPE-HPLC-MS/MS)技术,研究了广东省中山市某城镇污水循环活性污泥处理系统中5种典型新烟碱类杀虫剂污染特征及去除特性.结果表明,城镇污水循环活性污泥处理系统各工艺段均检测到新烟碱类杀虫剂残留(未检测到噻虫啉),且新烟碱类杀虫剂检出浓度随处理流程逐渐下降;其中缺氧运行阶段系统污泥对新烟碱类杀虫剂吸附作用较好,吸附率约为41%.新烟碱类杀虫剂在曝气运行阶段去除率为32%.污泥吸附和生物降解可能是城镇污水处理系统中新烟碱类杀虫剂的主要去除途径;好氧处理可能有利于新烟碱类杀虫剂的生物降解.当前城镇污水处理系统(CASS工艺)对新烟碱类杀虫剂去除效果不理想,大多数(91%)随出水排入受纳河流水体,可能会对周边水环境及水生态造成潜在巨大危害.

Pollution and removal characteristics of five typical neonicotinoid insecticides in a municipal wastewater recycling activated sludge treatment system in Zhongshan City,Guangdong Province,were studied using the solid phase extraction-high resolution liquid chromatographytandem mass spectrometry(SPE-HPLC-MS/MS)technique.The results showed that residues of neonicotinoid insecticides were detected in each section of the recycling activated sludge treatment system(except thiacloprid),and the residual concentration of neonicotinoids gradually decreased with the treatment process.Sludge in the anoxic stage showed high adsorption efficiency on the neonicotinoids with an adsorption ratio of about 41%.The removal rate of neonicotinoid insecticides in the aeration stage was 32%.Sludge adsorption and biodegradation could be two main removal pathways of neonicotinoids in the municipal wastewater treatment system,moreover,the aerobic treatment would be beneficial for the biodegradation of neonicotinoid insecticides.Results indicated that the current municipal biological wastewater treatment process(such as the CASS system)shows an unsatisfactory removal of neonicotinoid insecticides.About 91%of influent neonicotinoids are discharged into the receiving river with the effluent,which should cause potential damage to the surrounding water environment and ecology.