Removal of pharmaceuticals from a WWTP secondary effluent by ultrafiltration/reverse osmosis followed by electrochemical oxidation of the RO concentrate

This study aims to assess the removal of emerging contaminants from municipal wastewaters using a pilot system that integrated ultrafiltration (UF), reverse osmosis (RO), and electrooxidation, which mineralized the RO concentrate. Initially, the study monitored 77 emerging contaminants in the influent and effluent of a wastewater treatment plant (WWTP). Most of the compounds were detected in significant amounts in the WWTP effluent. A group of 12 compounds that represent the most prevalent therapeutic pharmaceutical categories was selected to monitor their removal by UF/RO. For the majority of the micropollutants, the UF removal efficiency was less than 20%. Excellent removal efficiencies were achieved with the RO treatment. As a result, the concentrations of the emerging contaminants in the RO permeate varied between 44 ng/L for naproxen and 4 ng/L for ofloxacin, and furosemide, bezafibrate and fenofibric acid were not detected. After the RO treatment, electrooxidation of the RO concentrate with boron-doped diamond electrodes reduced the total micropollutant content in the RO concentrate from 149 mu g/L to less than 101 mu g/L. Increasing the intensity of the electrooxidation treatment is expected to further reduce the micropollutant concentrations. (C) 2013 Elsevier B.V. All rights reserved.