Determination and assesment of disinfection by-product haloacetic acids in water treatment plants in İstanbul

Although chlorine has several disadvantages in water treatment, it is widely used for disinfection and oxidation purposes. Chlorine is preffered in water treatment mainly due to its high oxidation state, practical use, and low operation and maintenance cost. When chlorine is applied to drinking water processes, it reacts with NOM and forms various types of chlorinated disinfection by-products (DBPs). These halogenated by-products are considered to be possible human carcinogens and trihalomethanes (THMs) and haloacetic acids (HAAs) are most widely known DBPs. Through the different reaction reactivity of the NOM components with disinfectants, isolation and fractionation of NOM into more homogenous components is the better way to determining the DBP formation potential (DBPFP) of the waters. The disinfection of water with chlorine results in formation of disinfection by-products (DBP), such as trihalomethanes (THM) and haloacetic acids (HAA). It has been shown that natural organic matter (NOM) is a likely precursor material for THM and HAA formation. Among DBP found in chlorinated water, THM and HAA have been the focus of particular attention because they are considered potentially carcinogenic. Concerns about health risks associated with DBP have prompted several industrialized countries to establish maximum acceptable levels for THM and HAA concentrations in drinking water. In the United States (US), more stringent DBP regulations have been promulgated, placing limits on THM and HAA. The US Environmental Protection Agency (USEPA) drinking water limits for THM and HAA is 80 µg/L, and 60 µg/L, respectively. Recently most of the European countries regulated THM in their water at the level of 100µg/L. Further, there has been a 150 µg/L THM limit Turkish Drinking Water Regulation since 2005. US Drinking Water Regulations force water utilities to further increase DBP precursor removal with removing TOC below 2 mg/L. In order to decontaminate insalubrious microorganisms in the water, disinfection has been performed. The most common disinfection treatments method used in drinking water is chlorination. Disinfection by products (DBP) is formed as a result of chlorination of water which contains natural organic matter (NOM). Disinfection by products are; such as, trihalomethanes and haloacetic acids. In this study; for conducting experimental studies with haloacetic acids, water samples were gathered from ISKI Kağıthane, Büyükçekmece and Ömerli, then brought to the laboratory. The forming potential of HAA which is being appeared by adding disinfection in increasing concentrations is observed and the investigation of HAA in samples were conducted. In conclusion, since our results shows that, the administrative of drinking water treatment plants which operates either in Turkey or abroad, can be inspired such a study, that enable them to easily investigate the type and amount of insalubrious by products in pure water resources during chlorination of organic matter. Therefore, considering the gradual effect of chlorine on insalubrious microorganisms, organic matter and other parameters in pure water, the optimum concentration will be determined, hence minimum amount of DBP will be used in processes.