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

Abstract

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 (15μgL−1) in natural water. The nanofiltration system consisted of two 5.2m2 membranes operated in parallel. The solar photo-Fenton experiments were carried out in a 3m2 compound parabolic collector pilot plant having a 35L total volume. The ozonation system was a pilot plant providing a maximum concentration of 8.82gO3h−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.