Ozonation of Amoxicillin and Ciprofloxacin in Model Hospital Wastewater to Increase Biotreatability.

Sonja Šostar Turk,Mitja Kolar,Severina Aleksić,Katarina Premzl,Andreja Žgajnar Gotvajn

doi:10.3390/antibiotics10111407

Abstract

Amoxicillin (AMX) and Ciprofloxacin (CIP) are antibiotics commonly used in human medicine with high environmental toxicity and poor biodegradability. They have been found in various hospital effluents and groundwater, and their environmental impact is still not fully understood. In this work, we investigated the possibility of treating model wastewaters containing the antibiotics AMX and CIP using ozonation, with the addition of H2O2 under various conditions, including different pH values, H2O2, and ozone dosages. The quantification of and treatment efficacy for antibiotic removal were determined via solid phase extraction followed by chromatographic separation by liquid chromatography coupled with tandem triple quadrupole mass spectrometry (LC/MS/MS). This analytical system is quite efficient for the detection of all major antibiotic classes, even if they are present at very low concentrations. The efficiency of ozonation was determined by measuring the TOC (Total Organic Carbon) changes after ozonation of the model wastewater and by measuring the concentration of the two antibiotics. In a sequential activated sludge process of ozone-treated model wastewater, almost complete TOC removal and an overwhelming decrease in antibiotic concentrations (up to 99%) were observed. Ozonation resulted in complete removal of AMX and CIP in less than 30 and 120 min, respectively. The results of this work indicate that ozonation could be a suitable pretreatment method to reduce the toxicity of contaminants (AMX and CIP) and improve the biodegradability of hospital wastewater.

Highlights

Ciprofloxacin (CIP) from the fluoroquinolone family and Amoxicillin (AMX) from the beta-lactams group are used as broad-spectrum antimicrobial agents in hospitals, households, and veterinary medicine to treat bacterial infections
The treatment of wastewater containing antibiotics is very complex because these wastewaters contain antibiotics and inorganic and organic compounds, which all together can inhibit the activity of microorganisms in wastewater treatment plants (WWTP)
Detection was performed by multiple reaction monitoring (MRM) with positive electrospray ionization (ESI+)

Summary

Introduction

Ciprofloxacin (CIP) from the fluoroquinolone family and Amoxicillin (AMX) from the beta-lactams group are used as broad-spectrum antimicrobial agents in hospitals, households, and veterinary medicine to treat bacterial infections. These applications result in the significant contamination of wastewater and groundwater. Both substances can enter the environment through a variety of pathways, including human excreta, improper disposal of unused medications, industrial and hospital wastewater, and veterinary use. Conventional wastewater treatment plants are not primarily designed to treat biologically active substances; these are inadequately removed from the wastewater and, enter the aquatic environment [1,2]

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