Identification and Quantification of Chloroacetic Acid Derivatives in Tehran Drinking Water: The Role of Effective Factors in Chlorination Process

Abstract

In chlorination process for water disinfection, besides on inactivation pathogens, chlorine reacts with natural organic compounds that present in water and lead to the formation of chlorinated byproducts such as chloroacetic acids. In this research, effective factors in formation of compounds of halo acetic acids via propanone chlorination reaction were studied. The studied factors were concentration of organic compounds, chlorine dose and pH of sample. The tests results showed that these factors significantly affect on type and amount of chloroacetic acids. The increasing of propanone's concentration and chlorine dose cause an increase in all three types of compounds of halo acetic acids. While, decreasing of pH, leads to increasing of chloroacetic acid concentrations. Identification and determination of halo acetic acids performed with GC instrument and electron capture detector (ECD). The inherent advantages of GC-ECD were highly selective and good resolution toward halo acetic acids, so that the method was ideally suited for trace determination of chloroacetic acids in the investigated urban water samples. In order to evaluation of effective factors on formation of halo acetic acids, resulted from chlorination of organic compounds in urban water resources, several samples were monitored for parameters such as temperature, free residual chlorine, total organic halo acetic acids and pH of Karaj river, chlorinated water from Bilaghan lake, inlet and outlet of Jalalieh water treatment plant.