Not all water is safe to drink or to take a bath in. Some of it needs to be cleaned or purified before we can use or drink it. This is done in three basic steps:
- Water first flows through a basin which has chemicals in it . The bacteria , mud and other dirty substances that are in the water stick to these chemicals and move down to the bottom of the basin.
- Water then goes through a filter made up of sand and gravel . Other particles are filtered out.
- In the last phase chlorine is added to the water. It kills the bacteria that somehow get through.
Dirty, used water is carried away through sewage systems
. It often smells bad and has a lot of bacteria in it. Most cities have treatment plants
that turn used water into clean water that can be used to irrigate