UV‐C‐driven oxidation of ciprofloxacin in conventionally treated urban wastewater: degradation kinetics, ecotoxicity and phytotoxicity assessment and inactivation of ciprofloxacin‐resistant Escherichia coli

Abstract

BACKGROUND This study aims at evaluating the degradation of the antibiotic ciprofloxacin (CIP) in urban wastewater effluents using a UV‐C‐driven oxidation processes in the presence of hydrogen peroxide. Under the optimum experimental conditions, the phytotoxicity and ecotoxicity of the treated samples were investigated against one plant species (Sinapis alba) and a crustacean (Daphnia magna), respectively. The efficiency of the process to remove E. coli and ciprofloxacin‐resistant E. coli was also assessed. RESULTS Complete degradation of CIP was achieved within 15 min of treatment under the optimum concentration of the oxidant ([H2O2] = 10 mg L−1). The degradation rate of the antibiotic fitted pseudo‐first‐order kinetics. An increase in both shoot inhibition and root inhibition was observed, until 60 min of treatment, beyond which, the phytotoxic effect was eliminated. The results demonstrated the ability of the UV‐C process to reduce the toxicity towards D. magna by 40%, comparatively, to the untreated wastewater. The inactivation of E. coli and CIP‐resistant E. coli was achieved within 2 min of treatment. CONCLUSIONS The UV‐C/H2O2 process was successfully applied for the removal of CIP at low environmental concentration level. The treatment process was able to achieve a significant reduction of phyto‐ and eco‐toxic effects, as well as E. coli harbouring resistance to CIP. © 2016 Society of Chemical Industry

Co3(PO4)2/Ag3PO4 with enhanced simulated sunlight photocatalytic activity toward ofloxacin degradation and mechanism insight

“…In addition, the band gaps of Co 3 (PO 4 ) 2 and Ag 3 PO 4 are 4.40 and 2.33 eV respectively as calculated by UV-visible DRS. The potential of the CB can be calculated via Eqn(8). Hence we deduced that the E CB values of Co 3 (PO 4 ) 2 and Ag 3 PO 4 were −0.37 and 0.30 eV respectively.…”

“…For example, ofloxacin (OFX) is a frequently detected FQ antibiotic in various environmental samples such as wastewater treatment plant effluents, sea waters and surface waters in concentrations ranging from ng L −1 to µg L −1 . Previous studies demonstrated that FQs were subject to degradation in aqueous systems, mineralization of these compounds is often incomplete and many of the organic products identified retain the core quinolone ring structure, which is essential to FQs' antibacterial activities . The quantitative efficacy of various treatment processes for removing antibacterial activity remains unclear.…”

“…The quantitative efficacy of various treatment processes for removing antibacterial activity remains unclear. Escherichia coli is typically detected in urban wastewater treatment plant effluents as a popular bacterial pollutant indicator of fecal contamination and antibiotic resistance in wastewater . Its presence indicates water polluted with a number of pathogenic bacteria, while its complete absence confirms no pathogenic bacteria .…”

“…[3][4][5] Previous studies demonstrated that FQs were subject to degradation in aqueous systems, mineralization of these compounds is often incomplete and many of the organic products identified retain the core quinolone ring structure, which is essential to FQs' antibacterial activities. [6][7][8] The quantitative efficacy of various treatment processes for removing antibacterial activity remains unclear. Escherichia coli is typically detected in urban wastewater treatment plant effluents as a popular bacterial pollutant indicator of fecal contamination and antibiotic resistance in wastewater.…”

“…Escherichia coli is typically detected in urban wastewater treatment plant effluents as a popular bacterial pollutant indicator of fecal contamination and antibiotic resistance in wastewater. 8 Its presence indicates water polluted with a number of pathogenic bacteria, while its complete absence confirms no pathogenic bacteria. 9 Therefore using E. coli as a model bacterium to evaluate residual antimicrobial activity is an option to evaluate treatment efficacy for wastewaters containing antibiotics.…”