UV-disinfection in drinking water treatment as a key element of protection from water-borne infection

Summary

Various aspects of using different disinfection methods in drinking water treatment are considered. A short list of the most common water pathogens and their basic properties in relation to the use of disinfection with different chlorine-containing chemicals is presented. The necessity of using combined disinfection methods because of the insufficient efficiency of chlorination in relation to some chlorine resistant forms of microorganisms and protozoa is indicated. The international experience of introducing comprehensive schemes of chemical and chemical-free disinfection is considered; the domestic experience in this area is shown. By the example of assessing the morbidity rate of St. Petersburg and Nizhny Novgorod population the efficiency of combining traditional chlorination and other chemical methods of water treatment with subsequent UV-disinfection has been analyzed. It was found that combining several disinfection methods (as a rule, chlorination or chlorammoniation with UV-irradiation) provides for the significant decrease of infectious hepatitis and enteroviral infection case rate. The use of UV-disinfection in combination with other chemical methods provides for solving the problem of chlorination byproducts generation and at the same time ensuring a reliable barrier against chlorine resistant water borne pathogens. In addition the sanitation and epidemiologic safety of the population are significantly improved which is of primary importance in big cities with water sources being under high human-induced impact.

Key words

water intake , efficiency of well operation , well frameless slotted filter , hydrodynamic and hydraulic evaluation , filter permeability