Formation of chlorinated acetic acids during UV/H2O2-oxidation of ground water contaminated with chlorinated ethylenes

The performance of the UV/H2O2 process for purification of ground water contaminated with tri- and tetrachloroethylene was studied by measuring the formation of chloroacetic acids during treatment. UV/H2O2 oxidation has previously given good purification results and the aim of this study was to investigate the importance of potentially harmful by-products formed in the purification process. The rate of formation of chloroacetic acids during UV/H2O2 treatment compared with UV process showed that ultraviolet radiation alone produced partial destruction of chlorinated ethylenes but simultaneous use of radiation and hydrogen peroxide yielded considerably higher mineralization rates. The results are discussed relative to the available drinking water guidelines and toxicity values.