Occurrence of phthalate esters and microplastics in urban secondary effluents, receiving water bodies and reclaimed water treatment processes

Rumeng Wang; Min Ji; Hongyan Zhai; Yuan Liu

doi:10.1016/j.scitotenv.2020.140219

Occurrence of phthalate esters and microplastics in urban secondary effluents, receiving water bodies and reclaimed water treatment processes

Sci Total Environ. 2020 Oct 1:737:140219. doi: 10.1016/j.scitotenv.2020.140219. Epub 2020 Jun 15.

Authors

Rumeng Wang¹, Min Ji¹, Hongyan Zhai², Yuan Liu³

Affiliations

¹ School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
² School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China. Electronic address: zhaihy@tju.edu.cn.
³ North China Municipal Engineering Design & Research Institute Co., LTD, Olympic Road, 300381, China.

PMID: 32783843
DOI: 10.1016/j.scitotenv.2020.140219

Abstract

The occurrence of phthalate esters (PAEs) and microplastics (MPs) was simultaneously investigated in four wastewater treatment plants (WWTPs), receiving water bodies and reclaimed water treatment processes (RWTPs) in winter and spring. Four PAEs (dimethyl phthalate, dibutyl phthalate, diisobutyl phthalate, and di(2-ethylhexyl)phthalate) were detected. The total concentrations of PAEs were 568.9-1847.5 ng/L in the four WWTP effluents and 39.9-1847.5 ng/L in the four receiving water bodies. Di(2-ethylhexyl)phthalate had the highest concentration among the PAEs. MPs were mostly in the form of granules and fragments with size <0.01 mm in the four WWTP effluents (276-1030 items/L) and receiving water bodies (103-4458 items/L). The four WWTP effluents were important sources of PAEs to the receiving water bodies in spring but were not likely to be the sources of MPs. The overall removal rates of PAEs and MPs were 47.7%-81.6% and 63.5%-95.4% in the four RWTPs. Low or negative removal rates of PAEs were observed in chlorination and ozonation. Clarification, filtration (except ultrafiltration) and reverse osmosis were the dominant processes, contributing 42.7%-69.2%, 25.3%-59.3%, and 22.6%-51.0%, respectively, of the MP removal in the RWTPs. According to the Spearman analysis results, the levels of PAEs and MPs had more significant correlations with the physicochemical parameters of water samples from the RWTPs (including the WWTP effluents) than those of the receiving water bodies. The results indicated that the levels of PAEs and MPs in surface waters could be significantly influenced by the surrounding environment.

Keywords: Microplastics; Phthalate esters; Receiving water body; Reclaimed water treatment; Secondary effluent.