Aerated Grit Chambers

Aerated Grit Chambers

For grit removal considerations include head-loss requirements, space requirements, removal efficiency, organic content, and economics. In areated grit chambers, the most common means of grit removal, air introduced along one side near the bottom causes a spiralroll velocity pattern perpendicular to the flow through the tank. The heavier particles with their correspondingly higher settling velocities drop to the bottom, while the roll suspends the lighter organic particles, which are eventually carried out of the tank. The rolling action induced by the air diffusers is independent of flow through the tank. The heavier particles that settle on the bottom of the tank are moved by the spiral flow of the water across the tank bottom and then into a grit through or hopper. The grit collection through requires special design attention. The following are important: dimensions, depth in m (from 2-5 m), minimum detention time (at peak flow), air supply and type of diffuser.