The efficacy of ozone biocidal action against planktonic and sessile Pseudomonas fluorescens was studied using different contact times and biocide concentrations. Bacterial biofilms were formed on different metallic substrata frequently used as structura,

VIERA, M; GUIAMET, P; FERNÁNDEZ LORENZO DE MELE, M

BIOFOULING

TAYLOR & FRANCIS LTD

Año: 1999 vol. 142 p. 131 - 141

0892-7014

The efficacy of ozone biocidal action against planktonic and sessile Pseudomonas fluorescens was studied using different contact times and biocide concentrations. Bacterial biofilms were formed on different metallic substrata frequently used as structural materials in industrial installations. The results showed that the biocidal action of ozone against planktonic cells can be represented by a dose-response relationship in which the contact time factor was more significant than the concentration. The efficacy of ozone against sessile bacteria was lower than that found for planktonic cells. Turbulent flow significantly improved the inactivation rate, suggesting that a diffusional impediment was involved in the mass transfer process. However, diffusional resistance alone cannot explain the observed decrease in biocidal efficacy. Ozone penetration into the biofilm appeared to be a function of simultaneous diffusion and a reaction of the biocide in the biofilm matrix; the latter may be the result of microscale differences in biomass distribution as well as hydrodynamic conditions. In addition, oxidation by-products may contribute an additional resistance to ozone diffusion, which may be even higher than that of the biofilm itself