Question 26
Describe various steps of cleaning wastewater in a wastewater treatment plant.
Question 26
Describe various steps of cleaning wastewater in a wastewater treatment plant.
Wastewater is generated in homes, industries, agricultural fields and in other human activities. It contains a lot of impurities and is unfit for human consumption.
The various steps are:
(a) Wastewater is passed through bar screens. Large objects like rags, sticks, cans, plastic packets, napkins are removed.
(b) 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.
(c) The water is then allowed to settle in a large tank which is sloped in the middle. Solids like faeces settle at the bottom and are removed with a scraper. A skimmer removes the floatable solids like oils and grease. Water so cleared is called clarified water.
(d) Air is pumped into the clarified water to help aerobic bacteria to grow. Bacteria consume human waste, food waste, soaps and other unwanted matter still remaining in the clarified water.
(e) Clarified water is disinfected with chemicals like ozone and chlorine.
Wastewater is generated in homes, industries, agricultural fields and in other human activities. It contains a lot of impurities and is unfit for human consumption.
The various steps are:
(a) Wastewater is passed through bar screens. Large objects like rags, sticks, cans, plastic packets, napkins are removed.
(b) 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.
(c) The water is then allowed to settle in a large tank which is sloped in the middle. Solids like faeces settle at the bottom and are removed with a scraper. A skimmer removes the floatable solids like oils and grease. Water so cleared is called clarified water.
(d) Air is pumped into the clarified water to help aerobic bacteria to grow. Bacteria consume human waste, food waste, soaps and other unwanted matter still remaining in the clarified water.
(e) Clarified water is disinfected with chemicals like ozone and chlorine.
