Coagulation and Flocculation

If the water contains solids, coagulation and flocculation can be used to eliminate much of the material. Coagulation, a substance is added to water to change the behavior of the suspended particles. It makes the particles, previously they tended to repel one another, They are attracted to each other or to the aggregate material. Coagulation occurs during rapid mixing or stirring process that immediately follows the addition of the coagulant.

The flocculation process following the coagulation, usually it consists of a soft, slow agitation. During flocculation, more particles enter in reciprocal contact, bind each other to form larger particles can be separated by sedimentation or filtration. alum (aluminum sulfate) is a coagulant used both at the family level and treatment plants agua.31, 32 Natural coagulants include powdered seeds and tree Moringa olifeira types of clay such as bentonite.

Factors that may promote the coagulation-flocculation are the velocity gradient, time and pH. Time and velocity gradient are important to increase the likelihood that the particles together and allows more time for particles to descend, by gravity, and thus accumulate at the bottom. On the other hand, the pH is a prominent factor in destabilizing action of coagulants and flocculants substances.