Sewage

Sewage or domestic wastewater is the liquid waste produced by people when using the toilet, having a bath or shower or washing clothes and dishes. In some places, it also includes rain-water falling on houses and roads. It can also have liquid waste from factories in it. It flows in pipes called sewers to be cleaned up at a sewage treatment works.

Sewage is mostly water but it also has many microbes some of which can be harmful. It can have many chemicals in it which can also cause harm to animals and humans. Most sewage in poor counties is not treated and may spread disease. Sewage spills sometimes damage health and wildlife. ^[1]

Appearance

Pumping station lifting sewage to the treatment plant in Bujumbura, Burundi

Greywater (a component of sewage) in a settling tank

Sewage tends to be slightly warmer than in drinking water but it is more stable than the ambient temperature. The color of fresh sewage is slightly grey, whereas older sewage (also called "septic sewage") is dark grey or black. The odor of fresh sewage is "oily" and unpleasant. Older sewage has an unpleasant foul odor due to hydrogen sulfide gas and other decomposition by-products. Sewage can have high turbidity from suspended solids. ^[2][3]