Question

How is grit eliminated during primary treatment of sewage?

Answer 1

Treatment of sewage:

1. Sewage treatment consists of primary, secondary and tertiary treatments.
2. Primary treatment removes solids that either float or easily settle. It consists of screening, comminution, grit removal, and sedimentation.
3. Secondary treatment removes the soluble organic matter and more suspended solids. Aerobic bacteria acts on the wastes and breaks it down.
4. When the water is heavily polluted, secondary effluent may be treated further by several tertiary processes, to remove extra nutrients that might damage sensitive ecosystems.

Grit removal

1. Grit is small loose particles of stone and sand and is eliminated by sedimentation
2. Special chambers called grit chambers are designed to slow down the flow so that the grit settles down and does not cause wear and tear on pumps and other treatment plant equipment.