11种邻苯二甲酸酯在好氧污水处理系统中的归趋

邻苯二甲酸酯具有内分泌干扰效应,已对环境生物带来了较大的风险.研究了11种邻苯二甲酸酯的好氧生物降解性,及在活性污泥中的去除特性.快速生物降解性测试结果表明邻苯二甲酸二甲酯(dimethyl phthalate,DMP)、邻苯二甲酸二甲氧乙酯(dimethoxyethyl phthalate,BMEP)、邻苯二甲酸二乙酯(diethyl phthalate,DEP)、邻苯二甲酸二丁酯(dibutyl phthalate,DBP)、邻苯二甲酸二异丁酯(diisobutyl phthalate,DIBP)、邻苯二甲酸二戊酯(dinamyl phthalate,DNPP)、邻苯二甲酸二己酯(di-n-hexyl phthalate,DNHP)以及邻苯二甲酸-二(2-乙基)己酯bis(2-ethylhexyl)phthalate,DEHP]具有快速生物降解性,邻苯二甲酸二壬酯(dinonyl phthalate,DNP)及邻苯二甲酸二环己酯(dicyclohexyl phthalate,DHP)28d生物降解但未通过10 d观察期,邻苯二甲酸二苯酯(diphenyl phthalate,DPP)28 d生物降解率只有43.5%.好氧污泥降解动力学实验中,11种邻苯二甲酸酯(phthalic acid esters,PAEs)降解随时间变化呈典型的一级动力学规律,相关系数r20.96,降解速率常数为0.021~1.11h-1,降解半衰期在0.625~32.7 h之间.在室内好氧污泥模拟实验中,当水力停留时间为12 h时候,DNPP生物去除率为55%~70%,其余10种PAEs去除率大于80%,当水力停留时间为24 h时,所有PAEs去除率都达到90%以上.使用GC/MS分析了PAEs在好氧生化污水处理厂中的暴露水平,结果表明,DMP、DEP、DIBP、DBP以及DEHP在二级出水浓度分别为ND~44.0、ND~12.0、60.4~594、88.0~823和130~728 ng·L~(-1),PAEs在不同STP中的去除率结果差异较大,可能与STP运行工艺和运营水平有关.STP模型预测结果表明,PAEs在STP中的去除过程主要为生物降解,DPP、DNP和DEHP由于较高的lg Koc,可一定程度地被污泥吸附去除.

Fate of Eleven Phthalic Acid Esters in Aerobic Sewage Treatment System

Phthalic acid esters have potential environmental risk due to their endocrine disrupting effect. The biodegradable and removal characteristics of 11 phthalicacidesters were studied. The results showed that dimethyl phthalate(DMP), dimethoxyethyl phthalate (BMEP), diethyl phthalate(DEP), dibutyl phthalate (DBP), diisobutyl phthalate(DIBP), dinamyl phthalate (DNPP), di-n-hexyl phthalate(DNHP)and bis (2-ethylhexyl) phthalate (DEHP) had ready biodegradability, dinonyl phthalate (DNP)and dicyclohexyl phthalate (DHP)could be biodegraded but did not pass the 10 d window-period, and only 43.5% of diphenyl phthalate (DPP) was biodegraded on 28d. The degradation curves of 11 PAEs all obeyed typical first-order kinetics in aerobic sludge kinetics test, with the correlation coefficient r²>0.96, the degradation rate constant was between 0.021-1.11 h^-1, and the degradation half-life was between 0.625-32.7 h. In aerobic sludge simulation test, the removal rates of 10 PAEs were>80% at hydraulic detention time of 12h, except that DNPP was only 55%-70%. The removal rates of all PAEs reached 90% at hydraulic detention time of 24h. The relative high exposure in effluent for DMP, DEP, DIBP, DBP and DEHP was found by using GC/MS, with the residue concentrations of ND-44.0, ND-12.0, 60.4-594, 88.0-823 and 130-728 ng·L^-1, respectively. The results from STP model prediction showed that the removal in STP was mainly contributed by biodegradation, but for DPP, DNP and DEHP, the absorption removal was also an important removal way.