Evaluation efficiency of hybrid ozonation in an activated carbon bed for pretreatment hospital wastewater to reduce conventional pollutants and Ciprofloxacin and Vancomycin antibiotics

Abstract

Due to the presence of hazardous and recalcitrant pollutants in hospital wastewtare, more attentions have been paied by researchers on hospital wastewater in recent years. The presence of the residual pharmaceutical compounds, especially antibiotics, in these wastewaters, due to the inability of conventional treatment processes to remove them, will lead to the introduction of these compounds into the environment and will have its own environmental and health effects. In the present study, degradation of vancomycin and ciprofloxacin antibiotics from hospital wastewater using a catalytic ozonation process has been investigated. The effects of reaction time and concentration of phramaceauticals in ozone and catalytic ozonation processes with actived carbon were evaluated and finally, mathematical models for eliminating pollutants in these processes have been investigated. The results of the study show that single ozonation process can completely eliminate 6 mg/L of vincoumycin and ciprofloxacin in the 45 and 65 minutes, respectively. With regard to adsorption process, the maximum adsorption efficiency was 52% for vancomycin and 40.5% for ciprofloxacin. The use of catalytic ozonation process due to the synergistic effect of ozonation and adsorption resulted in improved process performance so that complete removal of 6 mg/L vancomycin and ciprofloxacin was reached in 20 and 25 minutes, respectively. Investigation of kinetics of removal of pollutants indicates that the removal of antibiotics in ozone and catalytic ozonation processes follows pseudo-first order kinetics. According to the results of this study, it can be concluded that the catalytic ozonation process can be considered as an appropriate option for pre-treatment of hospital wastewater.