AWWA WQTC52756

In arid and semi-arid regions of the southwestern US, environmental conditions such as high sunlightintensity and warm temperatures, and water supply practices such as reservoir depth and filling patterns favor algal growth and dissolved organic carbon (DOC) production which can cause a net increase in DOC downstream. Since DOCreacts with chlorine during disinfection to form disinfection byproducts (DBPs), it's presence is of concern. The sources and fate of DOC in the Verde River watershed and reservoirs near Phoenix, Arizona, have previously been studied. About 40% of the DOC exiting a two reservoir system on the lower Verde River was produced within the reservoirs, potentially by algal metabolites. The combination of algal metabolites as trihalomethane precursors in the Verde River watershed has long been acknowledged but not quantified. The purpose of this study was to determine the production and characteristics of algal-derived DOC/DBP precursors in order to infer the significance of algae on DBP formation in arid regions' surface water. Includes 30 references, figures.