Abstract |
This Master of Science (MSc) dissertation investigated the treatment of hospital wastewater. Samples were obtained from the Venizeleio General Hospital of Heraklion. In the first stage of this master thesis, the photocatalytic degradation of nine pharmaceuticals compounds (cefadroxil, amoxicillin, metronidazole, sulfamethoxazole, trimethoprim, diclofenac, acyclovir, valsartan, carbamazepine) was investigated using P25 TiO2 and ZnO as catalysts in three different matrices: aqueous, samples from primary and tertiary treatment municipal wastewater as well as the mixture of these compounds. Pharmaceutical compounds are well-known artificial chemical substances, which do not degrade biologically resulting the risk to the environment and public health. For this reason, these compounds need special management and treatment before they are discharged into the environment. Advanced oxidation methods are considered as promising and alternative methods, which could be combined with biological processes. The methods chosen for the treatment of this type of wastewater in this work, are photocatalysis with P25 TiO2 or 2% rGO-TiO2, photocatalysis with P25 TiO2 /H2 Ο2 and Photo Fenton. The first series of experiments, which concerned the investigation of the behavior of nine pharmaceutical compounds in different matrices and it aimed to examine the parameters that affect the process such as the type of catalyst and the initial concentration of the pharmaceutical pollutant. Subsequently, the photocatalytic process was carried out with the mixture of the nine pharmaceutical compounds in the matrices from the steps of WWTPs. In the second series, AOPs were applied to real hospital waste. Finally, the third series concerned with the application of the results of the above experiments on a pilot scale. Treatment efficiency was evaluated by the percentage of concentration of the pharmaceutical pollutant removal. As expected, the aqueous matrix had the best degradation rates, followed by the sample from primary and tertiary treatment of municipal wastewater. The results of the removal were improved when the initial concentration of pollutants was made from 25 to 5 ppm, while the type of catalyst was affected by the respective matrix as well as the pharmaceutical compound which would be degraded. Regarding the mixture of nine pharmaceuticals compounds, the results were satisfactory with some substances such as amoxicillin which reached to complete degradation. On the other hand, in this case of mixture xi the best degradation rates were observed on matrix of sample from tertiary treatment. Finally, the Photo Fenton method had the best results for treatment of hospital wastewater.
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