The presence of pathogenic antibiotic-resistant bacteria in aquatic environments has become a health threat inthe last few years. Their presence has increased due to the presence of antibiotics in wastewater effluents,which are not efficiently removed by conventional wastewater treatments. As a result there is a need to studythe possible ways of removal of the mixtures of antibiotics present in wastewater effluents and the antibioticresistantbacteria, which may also spread the antibiotic resistance genes to other bacterial populations. In thisstudy the degradation of a mixture of antibiotics i.e. sulfamethoxazole and clarithromycin, the disinfection oftotal enterococci and the removal of those resistant to: a) sulfamethoxazole, b) clarithromycin and c) to both antibioticshave been examined, along with the toxicity of the whole effluent mixture after treatment to the luminescentaquatic bacterium Vibrio fischeri. Solar Fenton treatment (natural solar driven oxidation) using Fentonreagent doses of 50 mg L−1 of hydrogen peroxide and 5 mg L−1 of Fe3+ in a pilot-scale compound parabolic collectorplantwas used to examine the disinfection and antibiotic resistance removal efficiency in different aqueousmatrices, namely distilled water, simulated and real wastewater effluents. There was a faster complete removalof enterococci and of antibiotics in all aqueous matrices by applying solar Fenton when compared to photolytictreatment of the matrices. Sulfamethoxazolewasmore efficiently degraded than clarithromycin in all three aqueousmatrices(95% removal of sulfamethoxazole and 70% removal of clarithromycin in real wastewater). The antibioticresistance of enterococci towards both antibiotics exhibited a 5-log reduction with solar Fenton in realwastewater effluent. Also after solar Fenton treatment, therewere 10 timesmore antibiotic-resistant enterococciin the presence of sulfamethoxazole than in the presence of clarithromycin.
- Antibiotic resistance
- Solar Fenton oxidation