Adsorption is one of the processes taking place during filtration, the other two being straining and sedimentation. It is not to be confused with absorption. With adsorption, very small particles of pollution adhere to the surface of the sand grains. This process is promoted by electrostatic charges within the particles (similar to a balloon 'sticking' to a wall). Once particles begin to adhere to the sand grains, a sticky coating builds up, which promotes further adherence of particles onto ... Continue reading ...
