Rejection of pharmaceuticals in nanofiltration and reverse osmosis membrane drinking water treatment

Abstract

This paper investigates the removal of a broad range of pharmaceuticals during nanofiltration (NF) and reverse osmosis (RO) applied in a full-scale drinking water treatment plant (DWTP) using groundwater. Pharmaceutical residues detected in groundwater used as feed water in all five sampling campaigns were analgesics and anti-inflammatory drugs such as ketoprofen, diclofenac, acetaminophen and propyphenazone, beta-blockers sotalol and metoprolol, an antiepileptic drug carbamazepine, the antibiotic sulfamethoxazole, a lipid regulator gemfibrozil and a diuretic hydrochlorothiazide. The highest concentrations in groundwater were recorded for hydrochlorothiazide (58.6-2548 ng L-1), ketoprofen (<MQL-314 ng L-1), diclofenac (60.2-219.4 ng L-1), propyphenazone (51.5-295.8 ng L-1) and carbamazepine (8.7-166.5 ng L-1). Excellent overall performance of both NF and RO was noted, with high rejection percentages for almost all of the pharmaceuticals investigated (>85%). Deteriorations in retentions on NF and RO membranes were observed for acetaminophen (44.8-73%), gemfibrozil (50-70%) and mefenamic acid (30-50%). Furthermore, since several pharmaceutical residues were detected in the brine stream of NF and RO processes at concentrations of several hundreds nanogram per litre, its disposal to a near-by river can represent a possible risk implication of this type of treatment. (C) 2008 Elsevier Ltd. All rights reserved.