Geriamojo vandens kokybės gerinimo Lietuvos miestų vandentiekiuose problemos

Abstract

Drinking water being supplied to Lithuanian cities is taken from underground scources only. Although physical, chemical and bacteriological properties of underground water are rather good, there also are problems in preparing of drinking water. In underground water of many water intakes the concentrations of iron, manganese, hardness and colour exceeds the permissible levels of drinking water standart. Although about 30 per cent quantity of supplying underground water by water supply systems in Lithuania are deironed in water treatment plants, there are a lot of water intakes in which such water treatment equipment absent. The special water treatment plants of manganese eliminate of underground water also not exists. In water intakes with artifically recharged water, are problems related to pollution of surface water due to human activities and organization of sanitary protection zones around the water intakes. The networks of water supply systems are made of steel and cast iron pipes. Its innerside is not covered with corrosion protected coats, therefore in pipelines the quality of drinking water becomes worse and decrease their hidraulic water permeability. The article presents the data about quality of drinking water supplying by water supply sistems of cities and recomendations how to solve these problems are given.