A water distribution system is responsible for delivering high quality water through tens of kilometers of water pipes. Pathogenic microorganisms may enter that distribution system even though the raw water was thoroughly treated at the source. Chlorine is widely used as a disinfectant in drinking water systems throughout the world. As chlorine travels through the pipes in the distribution system it decays and can react with a variety of materials that decrease its chlorine content. Nevertheless, most water suppliers attempt to maintain a detectable chlorine residual within the distribution system to minimize the potential for microbial growth. In Egypt, rural areas are supplied with groundwater or treated surface water throughout a Compact Unit. The water distribution system of a village located in Upper Egypt was studied to assess chlorine dose and to trace chlorine residuals. Drinking water in this village is produced by a compact treatment plant which treats raw water from the River Nile. Many water samples were collected from the distribution network and analyzed using a spectrophotometer to measure chlorine concentrations and other quality parameters. To obtain useful insight, field observations of chlorine have been incorporated into a computer program called EPANET developed by the US Environmental Protection Agency. The EPANET program can perform hydraulic and dynamic water quality simulations on any configuration of pipe networks. The obtained model was used to assess the applicable dose of chlorine added into the distribution system. Includes 13 references, table, figures.
