Mass balance analysis of triclosan, diethyltoluamide,crotamiton and carbamazepine in sewage treatment plants

摘要

The behavior of antibacterial triclosan, insect-repellent diethyltoluamide (DEET), anticonvulsantncarbamazepine, and antipruritic crotamiton was investigated at two sewage treatment plantsn(STPs) to clarify their complete mass balance. Twenty-four-hour flow-proportional compositensamples were collected from the influent and effluent of primary and final sedimentation tanks,na biofiltration tank and disinfection tanks. Sludge samples (i.e., activated and excess sludge)nand samples of the return flow from the sludge treatment process were collected in the samenmanner. The analytes in both the dissolved and particulate phases were individually determinednby a gas chromatograph equipped with mass spectrometer. Triclosan was dominantly detectednin the particulate phase especially in the early stage of treatment (up to 83%) and was efficientlynremoved (over 90%) in STPs, mainly by sorption to sewage sludge. Limited removal was observednfor DEET (55 ^ 24%), while no significant removal was demonstrated for crotamiton orncarbamazepine. The solid-water distribution coefficients (Kd, n ¼ 4) for triclosan (log Kd: 3.7–5.1),nDEET (1.3–1.9) and crotamiton (1.1–1.6) in the sludge samples are also determined in this study.nThese findings indicate the limitations of current sewage treatment techniques for the removalnof these water-soluble drugs (i.e. DEET, carbamazepine, and crotamiton).