Removal of Pharmaceutical Residues from Contaminated Raw Water Sources by Membrane Filtration

Abstract

In recent years, pharmaceutically active compounds (PhACs) have been recognised as persistent residues mainly being discharged via municipal sewage effluents into the aquatic environment (Halling-Sorensen et al. 1998; Daugthon and Ternes 1999; Kummerer 2001; Heberer 2002). In the meantime, more than 70 different PhACs have been detected at concentrations up to the μg l−1 level in sewage effluents, surface waters, bank filtrate, groundwater, and in a few cases even in drinking water (Heberer 2002). Thus, PhACs have also been recognised as potential contaminants of raw water sources to be used for the generation of drinking water. Besides other purification pretreatment or treatment techniques such as bank filtration (Heberer and Stan 1997; Heberer et al. 1997, 2001, 2002a; Brauch et al. 2000; Kuhn and Muller 2000; Reddersen et al. 2002; Verstraeten et al. 2002), artificial groundwater replenishment (Heberer and Stan 1997), soil aquifer treatment (SAT) (Drewes et al. 2002), slow-sand filtration (Preus et al. 2001; Ternes et al. 2002), ozonation (Andreozzi et al. 2002; Ternes et al. 2002, 2003; Huber et al. 2003) or filtration applying granular activated carbon (Ternes et al. 2002), membrane filtration using nanofiltration (NF) or reverse osmosis (RO) membranes is one of the most promising techniques for the removal of PhACs. NF and RO are used extensively in water and wastewater treatment. Additionally, RO is also used in desalination. NF distinguishes itself from RO by only retaining multivalent ions, which makes it a very economic alternative where the retention of monovalent salts is not required (Schafer et al. 2003). The main objective for the use NF or RO filtration in water and wastewater treatment is the removal of trace pollutants. However, the retention of such compounds is to date not well understood (Schafer et al. 2003).