Ozone and UV₂₅₄ Radiation for Municipal Wastewater Disinfection

• Published in: Water environment research Vol. 84; no. 11; pp. 2017 - 2027
• Main Authors: Blatchley, Ernest R., Weng, ShihChi, Afifi, Mehrnaz Zare, Chiu, Hsiao-Han, Reichlin, Douglas B., Jousset, Stéphane, Erhardt, Richard S.
• Format: Journal Article
• Language: English
• Published: Alexandria, VA Water Environment Federation 01-11-2012
• Subjects: Antiseptics; Applied sciences; Bottles; Disinfection; Dose response relationship; Drinking water and swimming-pool water. Desalination; E. coli; Escherichia coli - isolation & purification; Exact sciences and technology; General purification processes; Ozone; Ozone - chemistry; Pollution; Radiation dosage; Transmittance; Ultraviolet Rays; Waste Water - chemistry; Wastewater; Wastewater treatment; Wastewaters; Water Purification - methods; Water quality; Water treatment and pollution; Drinking water treatment; Ozonization; Ultraviolet radiation; Metabolic inactivation; Disinfection; Ozone; Urban waste water; Effluent discharge permit; Synergism
• ISSN: 1061-4303; 1554-7531
• DOI: 10.2175/106143012X13373550426634

Bench-scale experiments were conducted with municipal wastewater effluent samples to examine the feasibility of combined application of ozone and ultraviolet (UV) radiation for disinfection. Effluent samples displayed rapid initial ozone demand, which promotes ozone transfer but diminishes disinfection efficacy. Ozone doses up to 10 mg/L yielded only trace quantities of residual ozone; despite the fact that initial ozone demand was never exceeded, quantifiable (though variable) inactivation of E. coli was observed, along with modest improvements of UV transmittance. Results from collimated beam experiments demonstrated that compliance with effluent discharge permit limitations could be achieved consistently with a UV₂₅₄ dose of 12.4 mJ/cm² at a pre-ozonation dose of 2 to 3 mg/L. In the absence of pre-ozonation, consistent compliance was observed at a UV dose of 16.5 mJ/cm². No evidence of synergism between ozone and UV₂₅₄ radiation was found in the measured inactivation responses of E. coli.