Question

U might have ever seen the air vents from a sewer line in your homes. What is the purpose of that?

Answer 1

Wastewater must first flow through a trap, a U-shaped pipe that holds standing water and prevents sewer gases from entering your home. ... These drain pipes are connected to a vent pipe system that bring fresh air to the drain pipes, preventing suction that would either stop or slow the free flow of wastewater.

Answer 2

Answer:

Sewer system is a network of pipelines, hence when the wastewater flows through the pipes it compresses the air inside. Gas with bad odour is also produced by the microorganisms in the wastewater