Question

Sewage is mainly a

Answer 1

Hint:The wastewater that is released from houses, hospitals, offices, etc is sewage. Rainwater that runs down the streets is also sewage. The water that washes off the roads and rooftops has harmful substances. Wastewater contains dissolved and suspended impurities. These impurities are called contaminants.

Complete answer:
Cleaning of water is the process of removing pollutants from water before it enters any water body or is reused. The process of treatment of wastewater is called sewage treatment. In domestic cases, one set of pipes carry clean water and the other set of pipes carries used water. The network of pipes used for sewage treatment is called sewers. It is a transport system that carries sewage from the place where it is produced to the place of disposal or treatment through drainage systems.
Therefore, Sewage is mainly a liquid waste.

Note:
Wastewater is passed through bar screens where plastic bags, sticks, cans, napkins are removed. Then this water enters a grit and also a sand removal tank. The speed of the water is decreased so that the sand particles will get settled at the bottom. Then, the water is allowed to settle in a large tank sloped towards the centre. Solid wastes are settled and are then removed by a scraper. This water is called clarified water. Air is pumped in this water so that aerobic bacteria will grow. The bacteria consume the wastes by microbial action. Then 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 used for other purposes.