AWWA ACE54278

Polyaluminum chloride (PACl) coagulants are receiving more attention for use in drinking water treatment given their properties of being less acidic and less temperature-dependent than alum or iron coagulants. At the present time, comprehensive guidelines on the selection and use of these different PACls do not exist, and their performance when compared to alum for treatment of various types of raw waters has not been extensively studied. The primary goal of this research was to compare various forms of commercially available PACl coagulants to alum for treatment of a surface drinking water source of high color and organic content. Alum and PACl performance were examined under both warm and cold water conditions. Both phases of the experimental work included conventional treatment (i.e. sedimentation) and dissolved air flotation tests conducted at varying pH conditions and coagulant dosages. Includes 7 references, tables, figures.