Question: Describe the first three steps involved in getting clarified water from wastewate????
Answers
Answer:
•Wastewater is passed through bar screens which remove large objects like rags, sticks, cans, plastic packets, napkins etc.
•Water then goes through Grit and Sand removal tank, where sand, grit and pebbles settle down.
•Water is then allowed to settle in a tank where solids like faeces (called sludge) settle at the bottom and are removed with a scraper. A skimmer removes the floatable solids like oil and grease. Water so cleared is called clarified water. Sludge is used to produce biogas.
1.Wastewater is collected and passed through bar screens where plastic bags, sticks, cans, napkins, etc. are removed. This water then enters a grit and a sand removal tank.
2.The speed of the water is decreased so that the sand particles get settled at the bottom. After this, the water is allowed to settle in a large tank which is sloped towards the centre.
3.Solid wastes are settled and removed by a scraper. This water is known as clarified water. Air is pumped in this water to help aerobic bacteria to grow.
4.The bacteria consume the wastes by microbial action. These microbes settle down after several hours and the water at the top is removed.
This water is discharged into rivers and oceans or is put to other uses.
5.Nature cleans it up further. Sometimes it may be necessary to disinfect water with chemicals like chlorine and ozone before releasing it into the distribution system.