The purpose of this study was to find out whether the use of a combination of nanofiltration (NF) and solar photo-Fenton is more efficient than photo-Fenton alone as a tertiary treatment. Five different pharmaceuticals (carbamazepine, flumequine, ibuprofen, ofloxacin, and sulfamethoxazole) dissolved (100 mu g L-1) in natural water were preconcentrated by NF and treated by solar photo-Fenton. Photo-Fenton was operated at pH 5 with 5 mg L-1 of Fe2+. The NF system consists of two membranes operating simultaneously with a total surface area of 5.2 m(2). The photo-Fenton experiments were carried out in a 3 m(2) CPC solar pilot plant with a 35 L total volume. Hydrogen peroxide consumption and the pharmaceutical removal rate were used as the key evaluation parameters. It was demonstrated that at higher initial concentrations of microcontaminants, hydrogen peroxide is used more efficiently and NF pretreatment also reduced the photo-Fenton treatment time. Combined NF and photo-Fenton treatment was therefore found to be a promising approach for wastewater containing extremely low concentrations of microcontaminants. (C) 2012 Elsevier B.V. All rights reserved.