Laboratory scale study of photooxidation treatment for removal of pharmaceutical residues from water matrices

The effluent of wastewater treatment plants applying conventional three steps treatment procedure contains non-degradable organic micro-pollutants, mostly pharmaceutical residues. In Germany and Switzerland granulated activated carbon is used to reduce the concentration of these contaminants by about 80%. Another way to treat biologically treated wastewater is the fotooxidation using a photoreactor operating with a low pressure VUV light source. In framework of a laboratory scale project the degradation of diclofenac, naproxen and carbamazepin was studied in pure and wastewater matrices. The by-products formed during the fotooxidation were determined by UHPLC-Q-TOF system. The mineralization of organic pollutants was followed by measurement of total organic content of the treated solutions. In pure water matrix the degradation of diclofenac, naproxen and carbamazepin at concentration of 5 10-6 M needed 1: 5 and 10 minutes, however , in presence of treated wastewater matrix these time demand values increased to 5, 10 and 30 minutes, respectively. In order to reduce the treatment time oxygen or ozone was bubbled through the photoreactor resulting in mixing of water to be treated and higher number of OH• radicals.