It must be taken into account that there is a lot of variation in the size of the particles dissolved in water; there are very fine colloidal particles that make up a big part of water pollution.
For these types of particles that have a high stability in water, physical-chemical treatments are applied.
The objective of this treatment is to modify the physical properties of the contaminating particles by adding chemicals (coagulants and flocculants) to facilitate the formation of floccules and their subsequent separation or removal from the water.
This process involves 2 stages: