The purpose of this research is to study the related characteristics on proper major component and impurities of chlorine dioxide, which is considered to be an allowable treatment chemical for drinking water quality, in order to offer some important consideration and concerns to EPA for the legal announcement process. According to those collected information, USEPA, WHO and Germany are the few organization or countries who have established the related regulation on the use of chlorine dioxide at the present time. The generation of chlorine dioxide may produce some inorganic by-products at meantime, such as chlorite and chlorate. It has been noted that the toxicity of chlorite is more obvious. In order to minimize the production of inorganic by-products and the pollution from other impurities, it is suggested by this research that only gaseous chlorine dioxide can be used and added into the drinking water, and 1.4 mg/L and 0.8 mg/L are set as the maximum applied dosage and maximum allowable residual concentration, respectively, according to those referred regulations. Moreover, 1.0 mg/L as the upper limit or the residual chlorite concentration is also suggested.

chlorine dioxide, drinking water, disinfectant agent