CURRENT ISSUES OF MONITORING THE CHLORITE AND CHLORITE CONTENT IN DRINKING WATER AFTER OXIDATION DISINFECTION

Abstract

The use of oxidants (chlorine, chlorine dioxide and ozone) is a priority way of safe water supply. However, their use involves control of the formation, determination and normalization of chlorites and chlorates as by-products of disinfection. The aim of the work was to characterize the topical issues of monitoring the content of chlorites and chlorates in drinking water after disinfection with oxidants. Research methods included bibliometric and analytical. The results are as follows. The analysis of foreign and domestic normative documents testifies to the need to harmonize the current DSanPiN 2.2.4-171-10 “Hygienic requirements for drinking water suitable for human consumption” regarding the standardization of chlorites and chlorates in accordance with international requirements. It should be noted that these values, namely the normative values ​​for chlorites and chlorates at the level of 0.7 and 0.7 mg / l, respectively, were included in the latest version of the above-mentioned normative document DSanPiN 2.2.4-171-20. An analysis of the experience gained in Europe (European federation of national associations of water services) shows that the main source of chlorite and chlorate formation is not chlorine dioxide, as previously thought, but sodium hypochlorite. According to the WHO, chlorate is a typical by-product of disinfection in the treatment of water with oxidants (sodium hypochlorite, chloramines, chlorine dioxide, ozone). Currently, research on the development of technological principles for minimizing the content of chlorites and chlorates as by-products of water disinfection by oxidants in Ukraine has not been conducted. The above necessitates the implementation of the following tasks: generalization of research results of chlorite content in drinking water from centralized drinking water supply systems, where chlorine dioxide is used; development, testing and implementation of the method of determination of chlorates in drinking water; determination of the content of chlorites and chlorates in the finished sodium hypochlorite, which is supplied to water utilities, depending on the shelf life; monitoring the content of chlorites and chlorates in drinking water of settlements where sodium hypochlorite is used in the process of water treatment; determination of chlorate content in chlorinated tap water after its treatment with ozone; substantiation of optimal modes of water treatment with oxidants to minimize the content of chlorites and chlorates in drinking water from the water distribution network; development of technological principles for minimizing the content of chlorites and chlorates in drinking water after disinfection with oxidants.