title: Occurrence and removal of benzotriazole ultraviolet stabilizers in a wastewater treatment plant in China.
abstract: Benzotriazole ultraviolet stabilizers (BZT-UVs) have previously been found in sludge from wastewater treatment plants (WWTPs), which might be potential sources of BZT-UVs to the surrounding environment. In this work, the occurrence and fate of seven emerging 2-hydroxyphenyl substituted BZT-UVs were investigated in a Chinese WWTP. This group of hydrophobic BZT-UVs possess log Kow values ranging from 4.31 to 7.67 which could be associated with their fate in WWTPs. Field samples including 24 h flow composites of influent, effluent and grab sludge samples from different treatment processes were collected and analyzed. Concentrations of BZT-UVs dissolved in aqueous-phases were in the range of 4.88±1.35 (UV-234) to 34.5±12.4 ng L(-1) (UV-P) in the primary influent, while only UV-P and UV-328 were detected in the final effluent at concentrations of 10.5±6.59 and 2.74±1.73 ng L(-1), respectively. Considering the amount of target BZT-UVs adsorbed to total suspended solids (TSS), the daily mass flux in the primary influent of the WWTP ranged from 22.3 g day(-1) (UV-P, 7.99%) to 74.0 g day(-1) (UV-234, 26.5%). Total removal efficiency of the integrated treatment process ranged from 89.7% for UV-P to 99.7% for UV-234 suggesting nearly complete removal. Organic solid sedimentation in primary and secondary clarifiers was the dominant elimination route for BZT-UV analogues, which constituted 96.3% of the total removal efficiency. Advanced treatment (using ultraviolet disinfection) in this plant might further contribute to the high removal efficiencies (ranging from 19.6% to 77.3%).
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. gbjiang@rcees.ac.cn.
authors.forename: Shanjun
authors.initials: S
authors.lastname: Song
authors.forename: Ting
authors.initials: T
authors.lastname: Ruan
authors.forename: Thanh
authors.initials: T
authors.lastname: Wang
authors.forename: Runzeng
authors.initials: R
authors.lastname: Liu
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D002681:China; D004784:Environmental Monitoring; D014230:Triazoles / Q000032:analysis* / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D014230:Triazoles; D062065:Wastewater; D014874:Water Pollutants, Chemical; C012771:benzotriazole