Question

Describe various steps of cleaning wastewater in a wastewater treatment plant.

Answer 1

The steps performed for cleaning the wastewater before it is released into the water bodies is known as the wastewater treatment plant. The steps are -
i. A bar screen is placed through which the wastewater is passed to eradicate impurities from it like sticks, rags, cans, plastic packets, etc.
ii. Then a grit is placed after the bar screen, through which the filtered water is passed for more filtration of sand, grit, and pebble to settle down.
iii. Now, the water is passed to a large tank which is sloppy towards the middle and impurities like faeces settle down and later are removed with a scraper. The leftover wastewater is known as sludge.
iv. The sludge is further treated in a bio-gas plant for the production of biogas. The sludge had oils and fats remained it in which are removed by a skimmer.
v. The treated product is known as clear water, which is treated for the growth of aerobic bacteria by pumping air in it. The air consumes soap. human waste and any unwanted matter. It is kept undisturbed for several hours for the microbes to settle down at the bottom of the tank as activated sludge. The water is removed from the top.
vi. The completely treated water is discharged into a sea or river or into the ground.