Effectiveness of Advanced Oxidation Processes (AOPs) in the treatment of pharmaceuticals enrichesd effluents

• Main Author: Reis, Sara Lopes
• Publication Date: 2023
• Format: Master thesis
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10773/41136
• topic: Advanced Oxidation Processes; Ecotoxicity; Treatment; Effluent; Electro-oxidation; Danio rerio; Hediste diversicolor

The rise of population and consume promote more discharges of effluents rich in bio recalcitrant compounds, which need to suffer advanced treatment in order to reduce pollution levels on aquatic environment. Thus, the present work proposes to evaluate the efficiency of an Advanced Oxidation Process (AOP), by electro-oxidation, in the treatment of pharmaceuticals enriched effluents. To achieve this goal, were characterized the possible toxicological effects resultant from exposure of zebrafish (Danio rerio) embryos and polychaeta (Hediste diversicolor) to pharmaceutical industry effluents, before and after the treatment by electro-oxidation. The ecotoxicological characterization of effluents were performed trough the quantification of lethal and sub-lethal parameters [biochemical, using biomarkers as enzymatic activity of catalase (CAT), glutathione-peroxidase (GPx), glutathione-S-transferases (GSTs) and cholinesterases, and determination of lipid peroxidation levels (TBARS); and behavioural, such as swimming patterns in D. rerio and burrowing time, locomotion and feeding in H. diversicolor]. After exposure (acute and chronic) of zebrafish to effluent (non-treated and treated), no behavioural changes were observed. A decrease of antioxidant response (CAT and GPx) and increase of phase II metabolism (GSTs) and lipid peroxidation levels (TBARS) were observed, after acute exposure to non-treated effluent. After acute exposure of this species to treated effluent, only an alteration in GPx activity was observed (remain inhibited). After chronic exposure of zebrafish to non-treated effluent, it was possible to observe an increase of antioxidante defence (CAT and GPx) and a decrease in ChEs activity (neurotoxicity) were observed. After chronic exposure of zebrafish to treated effluent, only alteration in GPx activity was observed, that remains inhibited. For polychaetas exposures, after chronic exposure to non-treated effluent, no behavioural changes were observed. Moreover, on the biochemical level, it was observed an increase of antioxidant response (GPx) and a decrease in phase II metabolism (GSTs) and ChEs activities (neurotoxicity). When polychaetas were exposed to the treated effluent, it was possible to verify an increase of antioxidant response (CAT) as well as ChEs activity. In general, the electro-oxidation process suggests having the ability of degrade the compounds responsible for biochemical alterations. Thus, the treatment seems to be effective to decrease toxicity of the resultant effluent, since the toxicological effects of treated effluent are less extensive than those observed for the non-treated effluent.