Occurrence and fate of PPCPs in typical drinking water treatment plants in China

In this study, the occurrence and removal of twenty-nine pharmaceuticals and personal care products (PPCPs) in two water treatment plants (WTPs) in China were investigated. WTP1 employed ozonation and granular active carbon (GAC) filtration after coagulation and sedimentation, while WTP2 applied anthracite and GAC filtration instead. In the influent, six and four selected PPCPs with total concentrations of 554.97 and 12.94 ng/L were detected in WTP1 and WTP2, respectively (in October), among which, sulfamethoxazole and erythromycin were detected with highest concentrations due to their widely used as both human and veterinary medicines. PPCPs removal varied significantly among compounds and treatment units. In general, coagulation, filtration and single GAC units worked inefficiently and removed the detected PPCPs by less than 50%, as they were not hydrophobic. Ozonation was capable to eliminate a majority of PPCPs by more than 90%, which, however, presented limited mineralization and generated a certain amount of degradation by-products. To seek the improvement of PPCPs removal by coagulation and flocculation, the feasibility of adding hydrogen peroxide (H2O2) into the coagulation process (Fe2+ or Fe3+) to trigger the Fenton reaction was investigated. Results indicated that only under acidic condition, Fe2+ combined H2O2 efficiently removed PPCPs, while Fe3+/H2O2 also showed some removal capacity compared to coagulation process only. It will be impractical to employ this process under neutral pH. But when acidic wastewater is involved, this process may have its potential application.