The efficiency of removing metronidazole and ciprofloxacin antibiotics as pharmaceutical wastes during the process of composting

Nowadays, the increasing use of antibiotics to control the disease and also the inappropriate management and disposal of pharmaceutical wastes in various health centres, cause environmental problems and threaten human health. So, the aim of the present study was to investigate the efficiency of removing metronidazole and ciprofloxacin antibiotics, which are two highly consumed drugs, during the process of composting. In this experimental, applied study, a mixture of animal manure, fruit wastes, straw, and sludge was used to prepare the compost. Metronidazole and ciprofloxacin were added to the compost reactors at three concentrations of 20, 50, and 100 mg/kg. Moreover, the temperature, humidity, pH, and C/N conditions of the compost were controlled. The samples were taken from the reactors weekly, and then HPLC equipped with UV detector was used to analyse the antibiotics. Finally, all the data were analysed using SPSS software. The efficacy of removing antibiotics at the end of the thermophilic phase was 99.9, 96.73, and 93.48% for 20, 50 and, 100 mg/kg metronidazole and 89.47, 88.81, and 86.46% for ciprofloxacin, respectively. At the end of the process, the efficiency of metronidazole and ciprofloxacin removal for all the six reactors was 99.99%.The physical-chemical properties of the final compost were in the standard range. The use of an aerobic composting process to remove metronidazole and ciprofloxacin is considered as an effective and environmentally friendly approach. At the end of the process, 99.99% metronidazole and ciprofloxacin were removed.

Automated summary

The increasing use of antibiotics and improper management of pharmaceutical wastes pose significant environmental and health risks. This study aimed to investigate the efficiency of removing metronidazole and ciprofloxacin antibiotics during composting. Results showed that at the end of the thermophilic phase, the removal efficiency for metronidazole was 99.9%, 96.73%, and 93.48%, and for ciprofloxacin was 89.47%, 88.81%, and 86.46% at different concentrations. After the composting process, the overall removal efficiency for both antibiotics reached 99.99%. The physical-chemical properties of the final compost were within the standard range.