Introduction of Two-Stage Scheme of Water Disinfection at Waterworks of St. Petersburg

Summary

It is told about the modernization of systems of water disinfection at waterworks of St. Petersburg using sodium hypochlorite and ammonium sulphate. It has allowed to liquidate completely the threat of affecting the city’s territory and population with highly toxic substances (gaseous chlorine and ammonia) owing to possible failures at industrial sites of the State Unitary Enterprise Vodokanal Sankt-Peterburga and at transportation of liquefied chlorine and ammonia solutions, and also to exclude chlorine and ammonia influence on the environment in the case of equipment depressurization. Introduction of the technology of water disinfection with ultra-violet irradiation has favored the realization of the concept of multiple barriers at potable water disinfecting at the city’s waterworks.

Key words:

potable water , disinfection , liquefied chlorine , sodium hypochlorite , ammonia water , ammonium sulphate , ultra-violet irradiation

The use of ammonium sulfate in water treatment at the Metelevskii water treatment facilities of Tumen

Summary

The purpose of the work was increasing the efficiency of water disinfection technology at the Metelevskii water treatment facilities of Tumen without abandoning liquid chlorine use. The subject of the studies was the process of disinfection of the Tura river water and water after purification at the water intake near Metelevo settlement upstream of Tumen. For water disinfection at the municipal water treatment plants chlorine is used. The Tura river water contains high concentrations of organic and inorganic pollutants that cause high chlorine consumption; depending upon the season chlorine dosage varies from 3.5 to 17 mg/l. Therefore to ensure reliable disinfection of the water the use of high chlorine dosages is required. Besides, the total length of water mains and municipal distribution pipelines exceeds one thousand kilometers; whereas long-term operation caused their poor condition. Another problem arising in the process of river water treatment are specific odors (to 5 points) emerging occasionally in raw water that strengthen during disinfection with chlorine. Beginning from 2004 the specialists of the Metelevskii water treatment facilities have carried out laboratory and preparatory works on disinfecting river water with chlorination and ammoniation; and in accordance with the results – pilot tests. The main technical and technological aspects of using chlorammoniation at the Tumen water treatment facilities are considered. The results confirmed the efficiency of the given method of water disinfection. In addition, the water quality in the municipal distribution network was preserved, whereas the concentration of chlororganic compounds lowered.

Key words

ammonium sulphate , water supply plant , ammonization , chlororganic compounds , drinking water disinfection , chlorine consumption , chlorammoniation