- Step 1 - Wastewater is passed through bar screens. Large objects like rags, napkins, sticks, Solution, plastic packets are removed.
- Step 2 - Water then goes to a grit and sand removal tank. The speed of the incoming wastewater is decreased to allow sand, grit and pebbles to settle down.
- Step 3 - The water is then allowed to settle in a large tank which is sloped towards the middle. Solids like faces settle at the bottom and removed with scraper. And a skimmer removes the floatable solids like oil and grease. Water so, cleared is called ‘Clarified water’.
- Step 4 - Air is pumped into clarified water to help aerobic bacteria to grow. Bacteria consume human waste, food waste, soap and other unwanted matter still remaining in clarified water.
CBSE (NCERT) 7th Science Wastewater Story