Minimizing raw water NOM concentration through optimized source water selection

摘要

Natural organic matter (NOM) is present in all raw water supplies and is the major precursor to chlorinated disinfection by-products (DBPs). Given water quality considerations and budget realities, reduction in the amount of NOM entering treatment plants and a better understanding of NOM character are essential for optimizing treatment. A study of the unfiltered New York City (NYC) water supply system evaluated the extent to which alternative raw water selection strategies could reduce finished water DBP concentrations. A two-year monitoring program was conducted to establish spatial and temporal patterns of DBP precursors in NYC's upstate reservoirs. An operations model was driven with long-term time series of reservoir dissolved organic carbon concentrations to evaluate alternative operating rules to minimize precursor transport to terminal reservoirs. Results indicated that DBP precursors varied among reservoirs and over time but that modified reservoir operations could be effective at substantially reducing finished water DBP concentrations.