Ozone-initiated disinfection kinetics of Escherichia coli in water

• Published in: Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering Toxic/hazardous substances & environmental engineering, 2009-01, Vol.44 (1), p.48-56
• Main Authors: Zuma, Favourite, Lin, Johnson, Jonnalagadda, Sreekanth B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and physicochemical phenomena; Compressed; Contamination; Coronas; Counting; disinfection; Disinfection - methods; Escherichia coli; Escherichia coli - isolation & purification; Exact sciences and technology; Flow rate; Flux; Hydrogen-Ion Concentration; Hydroxyl radicals; Inactivation; Kinetics; Law; Microorganisms; Natural water pollution; Ozone; Ozone - metabolism; Pollution; Streams; Temperature; Water Microbiology; Water treatment and pollution
• ISSN: 1093-4529; 1532-4117
• DOI: 10.1080/10934520802515335

The effect of ozonation on the rate of disinfection of Escherichia coli was investigated as a function of ozone concentration, ozonation duration and flow rates. Ozone was generated in situ using Corona discharge method using compressed oxygen stream and depending on the oxygen flux the ozone concentrations ranged from 0.91-4.72 mg/L. The rate of disinfection of all the three microbes followed pseudo-first-order kinetics with respect to the microbe count and first order with respect to ozone concentration. The influence of pH and temperature the aqueous systems on the rate of ozone initiated disinfection of the microbe was investigated. The inactivation was faster at lower pH than at basic pH. Molecular ozone is found more effective in disinfection than hydroxyl radicals. Two reported mechanisms for antimicrobial activity of ozone in water systems from the literature are discussed. Based on the experimental findings a probable rate law and mechanism are proposed. Ozonation of natural waters significantly decreased the BOD levels of the control and microbe contaminated waters.