Water clarification by addition of colloidal silica followed by addition of polyelectrolyte

摘要

This invention relates to the clarification of waters containing turbidity-causing components. This method comprises the addition of an aqueous colloidal silica sol with average particle size 1 to 150 nm and water based polymeric coagulant of mw 2,000 to 2,000,000 to the turbid water. The components may be added independently, or blended together so that addition is simultaneous. The colloidal silica may also be conditioned by passing over a cationic exchange resin prior to addition of coagulant, which may be a cationic polymer. A composition of silica sol and coagulant is also claimed.