Question

Given below are the steps used in WWTP. Read the passage carefully and answer the questions that follow-
In the first step, large objects like rags, sticks, cans, plastic packets, napkins are removed. Water then goes to a large tank A. The speed of the incoming wastewater is decreased here. The water is then allowed to settle in tank B which is sloped towards the middle. Solids like faeces settle here at the bottom and are removed with a scraper. A skimmer removes the floatable solids like oil and grease. The settled solids are transferred to a separate tank where they are decomposed by the anaerobic bacteria. The biogas produced in the process can be used as fuel or can be used to produce electricity. Air is pumped into the water so cleared. The treated water has a very low level of organic material and suspended matter. It is discharged into a sea, a river or into the ground
Water is partially cleared after the process in tank B. What is the water so cleared called?​

Answer 1

clarified water

Water so cleared is called clarified water. Sludge is used to produce biogas. Clarified water is then passed through an aerator tank where air is pumped into the water.