Role of ozone and granular activated carbon in the removal of mutagenic compounds.

Abstract

The identification of certain organic compounds in drinking water has led water treatment specialists to be increasingly concerned about the eventual risks of such pollutants to the health of consumers. Our experiments focused on the role of ozone and granular activated carbon in removing mutagenic compounds and precursors that become toxic after chlorination. We found that if a sufficient dose of ozone is applied, its use does not lead to the creation of mutagenic compounds in drinking water and can even eliminate the initial mutagenicity of the water. The formation of new mutagenic compounds seems to be induced by ozonation that is too weak, although these mutagens can be removed by GAC filtration. Ozone used with activated carbon can be one of the best means for eliminating the compounds contributing to the mutagenicity of water. A combined treatment of ozone and activated carbon also decreases the chlorine consumption of the treated water and consequently reduces the formation of chlorinated organic compounds.

Towards improved drinking water safety: the use of in vitro bioassays to optimize treatment processes and assess chemical hazards

“…Nevertheless, both ozonation and GAC filtration or GAC filtration alone show great promise as barriers against bioactive compounds in drinking water production [8] and in the overall reduction of DBP formations [43]. Similar observations have been demonstrated elsewhere [15,49].…”

Pilot Scale Evaluation of Ozone and Other Drinking Water Disinfectants Using Mutagenicity Testing

“…Investigations involving the potential of ozone for producing mutagenic activity however are much less consistent, with reported levels ranging from those as high as for chlorination to virtually non-existent (Dolara et al, 1981;van der Gaag et al, 1982;Zoetemann et al, 1982;Bourbigot et al, 1983;Duguet et al, 1983;Meier and Bull, 1985;Cognet et al, 1985;Bourbigot et al, 1986). Studies which have incorporated granular activated carbon (GAC) filtration following disinfection have demonstrated that mutagenicity has usually been eliminated following this step (Bourbigot et al, 1983;van Hoof, 1983;Kruithof et al, 1985;Cognet et al, 1985;Bourbigot et al, 1986) and in some cases could not be detected even following TOC breakthrough (Monarca et al, 1983;Loper et al, 1985).…”

“…Studies which have incorporated granular activated carbon (GAC) filtration following disinfection have demonstrated that mutagenicity has usually been eliminated following this step (Bourbigot et al, 1983;van Hoof, 1983;Kruithof et al, 1985;Cognet et al, 1985;Bourbigot et al, 1986) and in some cases could not be detected even following TOC breakthrough (Monarca et al, 1983;Loper et al, 1985).…”