Removal of metronidazole from aqueous solution using ozonation process

Antibiotics have worldwide uses and they can enter water sources
through different ways. Due to their different inappropriate effects, they have created a major concern in
environmental control practices. Metronidazole (MTN) is an example of these antibiotics. This study was
performed to investigate the efficiency of ozonation process (SOP) in MTN removal from aqueous
solutions.
Materials and methods: The solution pH (3-12), reaction time and initial MTN concentration
(1-40 mg/L) were investigated for their effects on efficiency of the removal process. The MTN
concentration was analyzed by HPLC. Biodegradability improvement and mineralization rate were
studied by BOD5/COD and TOC tests, respectively.
Results: The optimum pH for SOP was 10. The best compatibility for drug degradation kinetic
was found with pseudo-second order (liner type II) model. The BOD5/COD increased from 0.09 in SOP
influent to 0.33 in SOP effluent and the MTN mineralization rate was about 68%.
Conclusion: Higher ozone decomposition in alkaline pH increased the radical production and
improved removal efficiency. Moreover, higher mineralization rate reduced the environmental risks of
effluent discharges.