Optimizing the Drinking Water Treatment Process (2011)

Undergraduates: Ashley Mui, George Dang

Faculty Advisor: Rose Cory
Department: Environmental Science

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One of the main goals of drinking water treatment is the removal of dissolved organic matter (DOM), a ubiquitous component of source water systems that may be harmful because of its ability to react with and form harmful disinfection byproducts during water treatment. To achieve this, drinking water treatment facilities usually perform a multi-step water treatment process consisting of coagulation, flocculation, and sedimentation. Of particular interest is the coagulation step, in which a chemical (called the floc) is added that attracts the DOM particles and causes them to coagulate and sink. Costs of coagulation are directly proportional to the amount of floc necessary to reduce DOM concentrations to acceptable levels. Fluorescent spectroscopy was used to characterize DOM in water samples taken from across the nation. Different coagulant doses of alum, a widely used floc, were applied to water samples. The fluorescent signatures of the water samples were then analyzed to determine the ability of coagulation to remove the more hydrophobic, terrestrially derived component of DOM, with the goal of determining the optimal floc concentrations for drinking water treatment.