Full Description

This research study focused on evaluating the organic matter (OM) phase-transformationbehavior when using metal-salt coagulants to treat source waters containing appreciable dissolved organic matter (DOM)concentrations. The OM phase-transformation protocol used here consists of three OM sizecategories - dissolved, colloidal, and particulate - operationally defined by filtration techniques. Particulate organic matter,formed by interaction of DOM with aluminum or iron coagulants, was defined as the fraction ofOM retained by a 1 m glass-fiber (GF) filter. The fraction of OM that passed a 1 m GF filterbut was retained by a 30 kiloDalton (kDa) ultrafiltration (UF) membrane was termed colloidalorganic matter, whereas any organics that passed a 30 kDa UF membrane following coagulationwere considered dissolved organic matter. Colloid formation during coagulation of drinking water may provide a means to achieveacceptable OM and turbidity removal at lower coagulant dosages, provided that the colloidalmatter formed is amenable to solid-liquid separation by subsequent filtration processes. Theprimary objective of this research was to evaluate how coagulant type and dose, as well as waterchemistry parameters including pH, turbidity, temperature, and DOM concentration, affect theformation of colloidal matter during coagulation of source waters with alum and ferric sulfate.Additionally, the relative performance of these coagulants was evaluated and the phasetransformation of DOM and coagulant metal compared for selected coagulation conditions. Includes 27 references, table, figures.

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Edition: Vol. - No. Published: 06/17/2005 Number of Pages: 18File Size: 1 file , 440 KB