Committee Report: Characterization of Inorganic Coagulant/Polymer Blends using refractive index and specific gravity measurements

Abstract

A proposal for a quality control procedure for inorganic coagulant/synthetic organic polymer blends will potentially fill a void where no AWWA standard or published quality control procedures currently exist. There are two broad classes of chemicals used for coagulation of particulate pollutants in drinking water treatment–inorganic metal salts and organic coagulant polymers. Metal salt coagulants include alum, ferric chloride, ferric sulfate, polyaluminum chloride (PACl), polyaluminum hydroxysulfate (PAHS), and aluminum chlorhydrate (ACH). Coagulant polymers include epichlorohydrin‐dimethylamine (epi‐DMA) polyamines and poly‐diallyldimethylammonium chloride (DADMAC) polymers. The mechanisms by which inorganic salts and organic polymers coagulate particles can be different. Consequently the simultaneous use of an inorganic salt and a coagulant polymer can sometimes result in better performance than either chemical is capable of producing alone, especially in high‐turbidity waters.