Raw water from groundwater, lakes, reservoirs, rivers and streams is rarely fit for human consumption without purification. In order to protect our health, all drinking water must be cleared of pathogens and impurities before it is used.
Coagulation with aluminium or iron salts is the most common technique to remove particles, colour, and impurities. The result is colourless, odourless water which is both palatable and enjoyable.
During the coagulation process, the impurities in the water aggregate in flocs which can easily be separated from the water. The choice of coagulant depends on the raw water quality and the separation method that is used.