Drains

Where does the water in the kitchen or bathroom go after you've used it?? When you remove the plug, the water runs down the drain, circulates through the curved tube under the sink and empties into thin pipes, which, at the same time, lead to wider ones. From these it goes to the sewers that are under the floor of the streets.

These sewers lead to larger ones, for which the water reaches a treatment plant.

On other sites, dirty or sewer water circulates through pipes that lead to concrete or steel tanks called septic tanks. These tanks are underground. Tiny bacteria turn dirty water into gas, in a clear liquid and in a solid substance called humus. Gas escapes into the air, the liquid floats through the pipes and the humus is deposited at the bottom of the tank. This humus is extracted from septic tanks, that need to be cleaned after a few years.