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