Drinking water quality aspect in ensuring the safety of water supply systems

In the definition of safety states of water supply system the quality of drinking water plays an important role. Especially, trihalomethanes as disinfection by-products have to be taken into consideration, because they are dangerous for consumer's health and their concentration usually increase in water distribution subsystem. In this paper the method of determining the thresholds for water quality states (included in the comprehensive method of safety analysis) is presented. The states are based on chloroform because its share in total trihalomethanes is about 80%. Using the tools of mathematical statistics the relationships between chloroform and other quality and operational parameters of drinking water were analyzed and applied to an estimation of quality states. Additionally, the estimation of quality states was based on chloroform in drinking water flowing out from water treatment plant to water pipe network. The study was based on data obtained from the real water supply system.