Determination of extent of antibiotic resistance bacteria in wastewater and removal of antibiotics using UV-H2O2 process

摘要

Emerging contaminants (ECs), like antibiotics in wastewater has drawn much attention in recent years. Several studies reported development of antibiotics resistant pathogenic strains due to long-term exposure of various antibiotics. The present studies show that the EC50 (measure of compound's 50% inhibition on bacterial growth) for the antibiotics on E. coli is on higher magnitude than environmentally significant concentrations. While checking for EC50 for E. coli against fluoroquinolone antibiotics (ciprofloxacin (CIP) and ofloxacin (OFL) in different municipal and hospital wastewater, the observed values were that E. coli isolated from municipal wastewater exhibits 4 to 11 times fold resistance whereas in case of hospital wastewater E. coli exhibits around 14 to 30 times fold resistance. In the degradation study of antibiotics, the results exhibit direct photolysis was found to be very slow compare to UV-H2O2 process in degrading the antibiotics, only 17% for CIP and 12% for OFL was observed through direct photolysis. Whereas, for the UV-H2O2 process, more than 80% transformation of antibiotics was achieved with peroxide dose of 5 mol H2O2/mol antibiotics within 60 min at pH 7.