Kinetic analysis of death of bacteria in CaO powder slurry

The process of Escherichia coli and Staphylococcus aureus death in calcium oxide (CaO) powder slurry was assumed to follow first-order reaction kinetics. The apparent death rate constant ( k) was found to increase with increasing powder concentration and was higher than that for a NaOH solution having the same pH as the CaO powder slurry. The slurry temperature was found to significantly affect the bactericidal action of the CaO powder slurry against both E. coli and S. aureus. The slope of the Arrhenius plot of k for both bacteria changed at a slurry temperature of approximately 22°C, suggested to correspond to a change in the activation energy required to induce the death of bacteria in CaO powder slurry as a result of a phase transition of the cell membrane.