Application of advanced oxidation processes followed by different treatment technologies for hospital wastewater treatment

Abstract

Hospital effluents are the sources for complex high percentage of micropollutants and till date no specific treatment have been investigated for the removal of pollutants. These effluents and their complex characteristics pose resistance to unit operation which undergoes in hospital wastewater treatment plants (WWTPs). In other words such complex contaminants are unable to removed completely through conventional treatment processes. The pharmaceutical residues entering into the environment may pose a serious threat to the water resources around the world. In past few years environmental scientists are more concerned towards the effluent generated from medical care facilities, community health centers and hospitals. In this study, seven multi-specialty hospitals with non-identical pre-treatment were selected for 3-aspects i.e. conventional wastewater characteristics, high priority pharmaceuticals and microbial analyses. The present work is to evaluate efficacy of advanced wastewater treatment methods with regard to removal of these 3-aspects from hospital effluents before discharge into a sewage treatment plant (STP). Based on test results, two out of seven treatment technologies i.e. MBR and CW effectively reducing conventional parameters and pharmaceuticals from secondary and tertiary treatments except regeneration of microbes were observed in tertiary level by these two treatments. The result also suggests that, MBR exhibited 100% elimination of ibuprofen, carbamazepine, frusemide while CW indicated 100% elimination of ofloxacin. Furthermore, two combinations of advanced oxidation process viz. ozonation (O3) and peroxone process (O3–H2O2) were demonstrated to oxidize pharmaceuticals. The operational key factors for AOP involve pH, O3 supply, contact time, and H2O2 concentrations. Based on pharmaceuticals reduction efficiencies, the conventional O3 alone is more efficient as compared to combine O3–H2O2 treatment. Hence results confirmed that, MBR coupled with ozone process proved as an optimal technology among the seven technologies for the pre-treatment of hospital effluent.