The sedimented and floating materials are removed by this treatment process.

The waste water released by our homes, industries, hospitals, offices has various impurities present in it which are removed by treating the waste water. The treatment process consists of various stages such as primary, secondary, tertiary treatment. Primary treatment includes the following steps:

● Wastewater is firstly passed through bar screens to remove larger objects such as plastic bags, cans etc.

● Water is then passed to sand and grit removal tank.

● Water is then allowed to settle in a tank where solids like faeces settle at the bottom called sedimented materials and oil and grease float over water. Sedimented materials are removed with a scraper and floatable materials are removed with a skimmer.

Water thus obtained is further treated for suspended and dissolved impurities which do not settle down and this is a part of secondary and tertiary treatments.