Occurrence and Fate of Amoxicillin and Penicillin G Antibiotics in Hospital Wastewater Treatment Plants: A Case Study – Gonbad Kavous, Iran

Abstract

Release of antibiotics to the environment as a result of wastewater effluent discharge is a cause for concern worldwide, as they pose a potential threat to  human health and the earth ecosystem. Penicillin and amoxicillin are widely used antibiotics. Despite their rapid hydrolysis in aqueous matrices, their  presence in the environment is widely investigated. The current study reported and analysed the current state of four hospital wastewater treatment  plants (WWTPs) in Gonbad Kavous, Iran, during 2019, from the perspective of amoxicillin and penicillin G removals. WWTPs were sampled at various  stages of the treatment process to determine at which stage the antibiotics are being removed. Concentrations of amoxicillin and penicillin G in raw  wastewater, analysed by HPLC, varied from 0.35 to 1.02 and 0.02–0.31 μgL⁻¹, respectively. These values reduced in the final effluent, corresponding to  overall efficiency in removing the studied antibiotics of 20-60.5%. Anaerobic processes (i.e. septic tank) slightly outperformed aerobic biological processes  for both antibiotics’ removal, and penicillin G was removed more efficiently than amoxicillin. Effects of wastewater physicochemical properties,  including chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS) on antibiotics removal, were  also studied. Whereas statistically significant correlations were noticed between COD, amoxicillin and penicillin G removals, their decline showed no  correlation with TSS removal. Our study shows that despite the deployment of treatment plants, a considerable amount of antibiotics is released into  receiving water bodies, resulting in significant amounts of these pharmaceuticals entering the environment. There is abundant room for further progress  in the detection and quantification of pharmaceuticals and other emerging contaminants in hospital wastewaters and their metabolites and  biodegradation products.