Destruction rate of volatile organochlorine compounds in water by ozonation with ultraviolet radiation

Rates of ozonation of 1,1,1-trichloroethane, trichloroethylene and tetrachloroethylene were measured in a rectangular thin channel reactor with a continuous flow of reactants under u.v. irradiation. These substances were chosen as model compounds of pollutants in groundwaters. The solution was buffered with KH₂PO₄-Na₂HPO₄ at pH = 6.9. The destruction rates were proportional to the dissolved ozone concentration and the u.v. intensity in the reactor. The u.v. irradiation of 8 W m^-2 at 253.7 nm enhanced the destruction rate of the organochlorine compounds by more than ten times that of the ozonation without u.v. irradiation. The activation energy for the decomposition of 1,1,1-trichloroethane decreased with increasing u.v. intensity. No volatile organochlorine compounds were newly formed in these reactions.