Four typical personal care products in a municipal wastewater treatment plant in China: Occurrence, removal efficiency, mass loading and emission

The occurrence, removal efficiency, mass loading and environmental emission of four categories (benzotriazoles; parabens; antimicrobials; benzophenones) of personal care products were simultaneously determined along the whole process line through an integrated approach (involving both dissolved and adsorbed phase) at a typical wastewater treatment plant in Hunan Province, Southern China. The results showed the prevalence of 13 and 11 target compounds in wastewater and suspended particulate matter, respectively. Twelve substances were detected in the sludge with the mean concentrations ranging from 0.12 to 591.23 ng/g dry weight. Benzotriazoles were the dominant compounds existing in water and antimicrobials were readily being absorbed onto suspended particulate matter and sludge. The overall removal efficiencies of compounds in the total treatment were -84.06%-98.53%. Mass balance results revealed that 85.17%-98.73% of the parabens and benzophenones were removed by degradation, while antimicrobials were removed by being adsorbed onto sludge. However, benzotriazoles could not be efficiently removed and the mass loss was lower than 61.03%. Although ultraviolet radiation played a limited role in removing most target compounds, it still had an impact on removing antimicrobials, 5,6-dimethyl-1H-benzotriazole and 2-hydroxy-4-methoxybenzophenone. The total mass loading and emission of personal care products were 506.35 mg/d/1000 people and 357.56 mg/d/1000 people, respectively. This work would help understand the removal approaches and real pollution of personal care products in the water environment.