ADVANCED OXIDATION PROCESSES FOR REMOVAL OF CONTAMINANTS OF EMERGING CONCERNS IN WASTEWATER IN VIEW OF THEIR REUSE

IN RECENT DECADES, THE TREATMENT OF THE SO-CALLED CONTAMINANTS OF EMERGING CONCERN (CECS) IN WASTEWATER HAS REPRESENTED A MAJOR SCIENTIFIC AND TECHNOLOGICAL CHALLENGE IN THE CONTEXT OF WATER REUSE, DUE TO THE LIMITED ABILITY OF CONVENTIONAL WASTEWATER TREATMENT PLANTS TO EFFECTIVELY REMOVE THESE COMPOUNDS. ADVANCED OXIDATION PROCESSES (AOPS) REPRESENT A PROMISING APPROACH FOR THE SAFE WASTEWATER REUSE. IN THIS THESIS, SEVERAL AOPS WERE INVESTIGATED, FOCUSING PRIMARILY ON PHOTOCATALYSIS USING A N-FE0/ZNS COMPOSITE, ZNO, AND RARE EARTH ELEMENTS OXIDES, AS WELL AS PEROXIDE- AND PERACETIC ACID-BASED PROCESSES. IN ADDITION, THE IMPLEMENTATION OF AN INTEGRATED PROCESS COMBINING ADSORPTION ONTO BIOCHAR AND ZNO PHOTOCATALYSIS WAS EXAMINED. THE REMOVAL OF BOTH CHEMICAL (ANTIBIOTICS AND TEXTILE DYES) AND BIOLOGICAL (ANTIBIOTIC-RESISTANT BACTERIA AND ANTIBIOTIC RESISTANCE GENES) TARGETS WAS INVESTIGATED, AS WELL AS THE TREATMENT OF SYNTHETIC LAUNDRY WASTEWATER. THE INFLUENCE OF WATER MATRIX AND OPERATIONAL PARAMETERS (E.G., POLLUTANT CONCENTRATION, CATALYST DOSAGE, CONTACT TIME AND PH) WAS EVALUATED. MOREOVER, ECOTOXICOLOGICAL ESSAYS WERE CARRIED OUT TO ASSESS THE ENVIRONMENTAL SAFETY AND EFFECTIVENESS OF THE APPLIED PROCESSES. OVERALL, THE INVESTIGATED PROCESSES PROVED EFFECTIVE IN ACHIEVING BOTH TARGET POLLUTANT REMOVAL AND TOXICITY REDUCTION. IN DETAIL, N-FE0 (0.45 G/L) REMOVED UP TO 86% AND 63% OF CHLORAMPHENICOL AND ACID ORANGE 7 FROM 20 MG/L SOLUTIONS, RESPECTIVELY, IN 10 MINUTES, SIGNIFICANTLY REDUCING THE INITIAL TOXICITY TOWARDS ARTEMIA FRANCISCANA. THE COMBINATION OF N-FE0 WITH ZNS ENHANCED THE AO7 DEGRADATION PERFORMANCE UNDER UV-A IRRADIATION, INCREASING THE REMOVAL EFFICIENCY TO 97% AFTER 10 MINUTES OF REACTION AND FURTHER DECREASING THE STARTING SOLUTION TOXICITY. ZNO UNDER VISIBLE LIGHT IRRADIATION ENABLED EFFICIENT DEGRADATION OF BOTH INDUSTRIAL TEXTILE INKS (85–100%) AND SOLUBLE ORGANIC MATTER IN SYNTHETIC LAUNDRY WASTEWATER (75%). CERIUM, LANTHANUM, AND LANTHANUM-DOPED CERIUM OXIDES ACHIEVED COMPLETE REMOVAL OF CHLORAMPHENICOL (1.00 G/L) WITHIN 15 MINUTES IN PRESENCE OF H2O2 AND UV-C RADIATION. CEO2 AND LA2O3 WERE ALSO EFFECTIVE IN THE DEGRADATION OF LEVOFLOXACIN (75% AND 83% REMOVAL AFTER 120 MINUTES, RESPECTIVELY) AND IN THE INACTIVATION OF LEVOFLOXACIN-RESISTANT ENTEROCOCCUS FAECALIS (COMPLETE INACTIVATION AFTER 5 AND 60 MINUTES, RESPECTIVELY) UNDER SIMULATED SOLAR IRRADIATION. UV-C AND PERACETIC ACID-BASED PROCESSES WERE EMPLOYED FOR THE INACTIVATION OF MULTIDRUG-RESISTANT ESCHERICHIA COLI, SHOWING ENHANCED PERFORMANCE WHEN APPLIED SEQUENTIALLY. THE ADSORPTION CAPACITY OF BIOCHAR TOWARDS CHLORAMPHENICOL AND SYNTHETIC LAUNDRY WASTEWATER WAS ASSESSED AND WAS FURTHER IMPROVED BY ZNO FUNCTIONALIZATION, AS A SYNERGISTIC ADSORPTION-PHOTOCATALYSIS MECHANISMS OCCURRED UNDER UV-A IRRADIATION. A CORRESPONDING REDUCTION IN SOLUTIONS’ TOXICITY WAS ALSO OBSERVED. BASED ON THESE RESULTS, FURTHER STUDIES SHOULD FOCUS ON OPTIMIZING ENERGY CONSUMPTION AND IMMOBILIZING PHOTOCATALYSTS ONTO MACROSCOPIC SUPPORTS, INCLUDING BIOCHAR, IN ORDER TO FURTHER PROMOTE CIRCULAR ECONOMY PRINCIPLES IN WASTEWATER TREATMENT.