Identification of different water types in case of the municipal distribution network failures

Summary

Prompt localization of latent and apparent water losses has been an important task of the «Mosvodokanal» JSC activities. The time needed for eliminating failures in the municipal distribution network depends significantly on the efficient identification of the leakage source and owner of the service lines. The issues of sample identification under different emergency conditions are considered. It is shown that alongside with instrumental methods of water leak detection laboratory analytical methods can also be used. Underground water inflow is a most elementary case of water losses. Taking into account that surface water from the Moskva and Volga rivers serves as a water source of the public water supply the presence of fluorides, low mineral content and the absence of organic pollutants are reliable evidences of the underground origin of the water inflow. At the same time high mineral content, presence of phosphates, ammonia salts, high permanganate values evidence the inflow of polluted wastewater. A reliable proof of leakage water originating from the public water supply is the presence of water purification by-products, chloroorganic compounds in particular. The experimental results showed that the minimum significant chloroform value in real samples of leakage water in the Moscow public water supply was 3 µg/l. This chloroform concentration remains unchanged with time with the disinfection practice adopted at the Moscow water treatment plants: chlorammoniation during both primary and final chlorination. The statistically processed data arrays of special experiments and real samples for a few years indicate that the given concentration of chloroform detected in the sample is a proof of water originating from public water supply systems.

Key words

water supply network , water leaks , fluorides , laboratory control , chlororganic compounds , residual chlorine , sample identification

Methods of supplementary chlorination in the long sections
of the water mains in Novokuznetsk

Summary

According to SanPiN 2.1.4.1074-01, while supplying water to the distribution network, the concentration of residual free chlorine in it should be from 0.3 to 0.5 mg/l, and that of residual combined chlorine – from 0.8 to 1.2 mg/l; in the distribution network, the concentration of residual free chlorine is not regulated; however, the quality of drinking water should be epidemically safe. To address this problem, the specialists of the chief process engineer department at Vodokanal LLC studied the technologies of supplementary chlorination in the water transportation system at one or several stages, and of chlorammoniation at the water treatment facilities. It has been established that chlorammoniation provides for a prolonged action of chlorine in water and prevents the formation of carcinogens. However, after the introduction of ammonia, a foreign odor and aftertaste (pharmaceutical, medicinal) appeared in all analyzed samples. It was experimentally proved that during chlorammoniation in summer during hot periods and with the presence of foreign moldy odor in the river water, ammoniation did not either prevent or reduce the intensity of foreign odor and aftertaste in drinking water. Various technologies of supplementary chlorination in the water transportation system were studied and local supplementary chlorination of drinking water by membrane electrolysis was recommended.

Key words

chlorammoniation , residual chlorine , membrane electrolyzer , supplementary chlorination , water odor and aftertaste

Скачать/download (PDF) free access

Domestic technologies and equipment for chemical free treatment of water and wastewater of the Siberian cities and industries

Summary

The chemicals used in liquid and gaseous media treatment and purification either stay intact in the processed environment or disintegrate and react with the processed environment or admixtures in it and form numerous secondary and often toxic products. In this context chemical free methods of media purification aiming at their environmental safety are of most interest. Chemical free methods of treatment do not result in the formation of such a big amount of secondary products; whereas the efficiency of their use is often higher because they less depend on the type and structure of the targeted substance or admixture as well as on the conditions of use. Ultraviolet irradiation has been the most efficient and widely used method of chemical free disinfection of effluents both in Russia and abroad. The capital expenses for UV-disinfection are significantly reduced since there is no need in constructing contact tanks for chlorination and dechlorination; in addition the absence of chemical consumption eliminates the need in constructing a chemical plant and installing dosing systems. Using the example of the Siberian Region the advantages of using UV-irradiation in wastewater treatment is described.

Key words

ultra-violet irradiation , ecological safety , water disinfection , chlororganic compounds , residual chlorine , dechlorination , chemical free disinfection