Assessment of the fate of some household micropollutants in urban wastewater treatment plant

Everyday domestic activity is a significant source of water pollution. The presence of six household micropollutants in an urban wastewater treatment plant (WWTP) was assessed in wastewater and sludge. A multi-target analytical method was developed for the quantification of ibuprofen, erythromycin, ofloxacin, 4-nonylphenol, 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan), and sucralose. The micropollutants were extracted from the liquid and solid phases and their concentrations were determined by LC-MS/MS. The efficiency of micropollutants' removal within a conventional activated sludge process was assessed. From 50 % to 90 % of ibuprofen and erythromycin was removed from the wastewater liquid phase. Their removal can be attributed to biological degradation as they were not found adsorbed on the outlet sludge. Ofloxacin and triclosan were removed from the liquid phase with similar efficiencies; however, they were adsorbed on the sludge, so it was not possible to determine their removal mechanism (whether biodegradation or displacement to solid phase/sequestration). Sucralose was not removed from wastewater (3 mu g L-1 in inlet and outlet liquid phase) and not adsorbed on the sludge. 4-Nonylphenol concentrations were sometimes higher in the WWTP outlet water; this may relate to the degradation of alkylphenol ethoxylates in the wastewater treatment process. 4-Nonylphenol was always present in the outlet sludge.