Pathogen Re-Growth in UASB Effluent Disinfected By UV, O₃, H₂O₂, and Advanced Oxidation Processes

Abstract

Disinfection of anaerobically treated effluent (UASB) was carried out to eliminate the enteric pathogens by using UV irradiation, peracetic acid, H₂O₂, O₃ and advanced oxidation processes (O₃/H₂O₂, O₃/UV and H₂O₂/UV). Re-growth potential of these pathogens was monitored in terms of time and temperature. Inactivation of pathogens by ozone at the rate of 300 mg/h for 20 minutes approached 99%. UV irradiation resulted in 99% pathogen removal at irradiation time of 120 seconds. A dose of 170 mg/L H₂O₂ eliminated more than 99% pathogens. Samples disinfected with UV, H₂O₂ and O₃ showed gradual re-growth with an increase in time and temperature (from 20 to 35°C). However, disinfection with AOPs proved to be the most effective tool resulting in reduction of treatment time taken by individual processes, also the disinfected samples showed minimal re-growth revealing the superiority of their combined effects.

Keywords:

• Ozone
• Anaerobically Treated Effluent (UASB)
• Pathogens
• Disinfection
• Advanced Oxidation Processes
• Re-Growth

ACKNOWLEDGMENTS

Financial support extended by the Higher Education Commission, Government of Pakistan under the indigenous Ph.D. Scholarship Scheme, is gratefully acknowledged.