AWWA ACE59868

The treatment procedures aimed at producing drinking water induce major modifications on the properties of natural organic matter (NOM). A better knowledge of the fate of NOM within distribution systems can be valuable information for utilities that practice re-chlorination and for large systems where residence time of water is high. The aim of this investigation is to characterize the reactivity of DBP precursors occurring in water distribution systems by demonstrating the temporal and spatial evolution of the organic matter (OM). For example, four points of the distribution system of Quebec City (Canada) water utility were selected for the collection of data. The applied strategy allows for an evaluation of the impact of residence time on the formation of DBPs and on the changes of OM throughout the pipes. The methodology developed for this project is based on existing NOM fractionation techniques (using DAX-8 and XAD-4 resins) allowing to observe behavior that cannot be observed easily when the integral sample is manipulated. Finally, OM reactivity is investigated using experimental chlorination tests on fractionated and non-fractionated samples under controlled conditions of pH, temperature and chlorine dose. Includes 11 references, table, figures.