Purification of water.

摘要

This invention relates to a composition for the purification of water which includes a suitable coagulant for coagulating solid impurities dispersed in the water to form flocs. It also includes an organic hydrophilic colloid capable when dispersed in the water, of absorbing large quantities of water to form a sol for aggregating the flocs, the proportion of organic hydrophilic colloid in the composition being such that when the composition is used to purify the intended quantity of water, the organic hydrophilic colloid does not interfere with coagulant dispersal in the water or with floc formation. The invention also relates to a method of purifying water which includes clarifying the water by dispersing the composition in the water to be treated to flocculate suspended solid impurities therein, and separating the flocs from the clarified water, the quantity of composition added being such that the quantity of colloid in the water does not exceed 50mg/litre.