Pharmaceuticals removal from natural water by nanofiltration combined with advanced tertiary treatments (solar photo-Fenton, photo-Fenton-like Fe(III)-EDDS complex and ozonation)

The main purpose of the study was to compare three different advanced tertiary treatments, solar photo-Fenton, solar photo-Fenton-like Fe(III)-EDDS complex and ozonation. Five pharmaceuticals, carbamazepine, flumequine, ibuprofen, ofloxacin, and sulfamethoxazole, selected as model micropollutants for the study, were dissolved (15 mu g L-1) in natural water. The nanofiltration system consisted of two 5.2 m(2) membranes operated in parallel. The solar photo-Fenton experiments were carried out in a 3 m(2) compound parabolic collector pilot plant having a 35 L total volume. The ozonation system was a pilot plant providing a maximum concentration of 8.82 g O-3 h(-1). Contaminants were measured by ultra-performance liquid chromatography, previously preconcentrated by solid phase extraction. Nanofiltration provided a large volume of practically clean water (permeate) and a concentrated stream requiring further treatment. General advantages of the combined process over direct treatment due to reduction in the total volume to be treated were: (i) lower AOP treatment time, (ii) more efficient reagent consumption, and (iii) lower acid consumption for carbonate removal. The photo-Fenton-like Fe(III)-EDDS complex makes it possible to work at over pH6. Ozone consumption was lowered by combining ozonation with nanofiltration instead of using direct ozonation. (C) 2013 Elsevier B.V. All rights reserved.