Removal of some pharmaceutical residues by advanced chemical oxidation process

In this thesis work, advanced treatment methods of pharmaceutical residues that are not removed at all or very little removed by using some of conventional water and wastewater treatment methods was studied. Advanced oxidation methods studied in this thesis was followed as Fenton (Fe2+/H2O2), H2O2 alone, the use of ozone (O3), ultraviolet (UV), ultraviolet/hydrogen peroxide (UV/H2O2), ultrasound (US) and ultrasound/hydrogen peroxide (US/H2O2) processes. Removal efficiency of each process was investigated with comparatively. Determination of optimum conditions was aimed in order to obtain the best removal efficiencies for these processes. In accordance with this purpose, pharmaceutical residues commonly encountered in surface water and wastewater such as Carbamazepine, Caffeine and Paracetamol were selected. In addition, one of the metabolite of Caffeine called as 1,7-dimethylxanthine has also been investigated. In this study, pharmaceutical concentrations were measured by using a LC-MS/MS instrument. In the Fenton process which is one of the advanced treatment methods, different H2O2 and Fe2+ concentrations were tested while the pH value below 3.5 and the process time as 30 minutes were kept constant. For all of three pharmaceuticals, almost up to 100% removal has been achieved. In the process of ozonation, at the end of the 30 minutes process, by applying 50 L/h gas flow rate at the natural pH of the water, 100% removals of pharmaceuticals were achieved for Paracetamol, Carbamazepine and Caffeine pharmaceuticals at 0.46 mg/L, 0.46 mg/L and 3.20 mg / L ozone concentrations, respectively. A high removal rate was reached at the end of a 30 minutes period in the UV process; on the other hand, the removal rates were achieved in a shorter period of time for all three pharmaceuticals in the UV process with H2O2. Moreover, H2O2 concentrations were increased as the removal rates increased. The last processes which are the US and US/H2O2 for the removal of pharmaceutical residues gave the lowest removal values comparing with other processes that had been tried before. The US process cannot be removed any pharmaceutical residues at the end of the 60-minute period for own pH value of natural water; however, US/H2O2 process with 7 mg/L H2O2 concentration yields 33%, 25% and 30% removals for Carbamazepine, Caffeine and Paracetamol, respectively. Studies showed that pharmaceutical residues could be removed efficiently from waters by the advanced oxidation processes Keywords: Treatment, Pharmaceutical Residues, Chemical, Oxidation, Process.