The occurrence and removal of organophosphate ester flame retardants/plasticizers in a municipal wastewater treatment plant in the Pearl River Delta, China

The occurrence, distribution and main removal pathway of seven widely used organophosphate esters (OPs) in a municipal wastewater treatment plant (WWTP) located in the Pearl River Delta were investigated. Their daily discharge load into the Pearl River via effluent was also estimated. All the target analytes were detected in wastewater, suspended particle and dewatered sludge, with tri-n-butyl phosphate (TBP) and tris(2-butoxyethyl) phosphate (TBEP) as the main components. The total concentrations of TBP and TBEP were 21271.8ng L-1 and 4349.4ng L-1, 3105.1ng L-1 and 494.5ng L-1 in influent wastewater and final effluent, respectively. These results indicated that non-chlorinated OPs were removed efficiently in the WWTP, while chlorinated OPs passed through the WWTP unchanged due to their resistance to current wastewater treatment technology. Approximate 91.4g of non-chlorinated OPs and 23.4g of chlorinated OPs per day were discharged into the Pearl River via effluent, 2.4g of non-chlorinated OPs and 0.6g of chlorinated OPs entered the environment following sludge disposal.