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Chlorine gas ( Cl 2 ) is commonly used in municipal water treatment systems . The teens also helped instal five solar-powered water purification systems in five villages to help avert the threat of waterborne diseases . The course will also cover the theory and design of conventional potable water distribution systems . For example , members of the drinking water and water treatment systems sector council include national organizations such as the American Water Works Association and the Association of Metropolitan Water Agencies and also members of these associations that are representatives of local entities including Breezy Hill Water and Sewer Company and the City of Portland Bureau of Environmental Services . Today , the waterways are valued as a leisure and recreation resource for millions , are a part of our land drainage and water distribution systems whilst still providing an environmentally friendly means of transport for coal , aggregates and other materials . Later , indices were developed to predict the behavior of calcium carbonate to protect water distribution systems from scale and corrosion . Marks dominant research thrust is to develop high-flow pathogen concentrators that can be coupled to biological and chemical sensors as well as water purification systems . Urban centers and towns will derive health and economic benefits from restored water supply systems ; clean-up and repair of drainage and sewage facilities ; and repair of roads , street lighting , and other public utilities . These regulations provide for water standardization only for the waters to be used in water supply systems , recreation , industry and agriculture , without suitable standards for aquatic ecosystem protection and are only concerned with chemical , microbiological , radioactive and biological content . For example , members of the drinking water and water treatment systems sector council included the American Water Works Association as well as local entities , such as the City of Portland Bureau of Environmental Services . This form of chlorine is commonly used in municipal water treatment systems . Last spring found Stanford MBA students learning by example from social entrepreneurs in Brazil , gutting a house in hurricane-ravaged New Orleans , and experimenting with prototype water distribution systems in rural Myanmar . " This would include the specific tub and water recirculation systems used . Nitrate + nitrite-N concentrations in two wells exceeded the 10 mg / L standard for public water supply systems . Household water treatment systems will not provide sufficient protection and may themselves need to be disinfected . Dam , located on the Tuckasegee River in Jackson County , NC , serves as the impoundment for two public water supply systems .