Science....hmmm.....

Hello, this is what I learnt in Science. I feel like it will help you to learn more on Science...

Water Supply in Cities

In cities, sewage water is filtered through big metallic filters in order to retain solid materials and then the water is drained into rivers.
   
           The water supplied in cities is from the water work stations. In these stations, water is purified by the following steps before it reaches us.

1. Sedimentation. The water is allowed to stand for few hours.As a result, the suspended impurities settle down. This process is called sedimentation.
2. Decantation. The clear water is then decanted into another container.
3. Loading. In this process, the fine suspended impurities are separated by loading them over alum.
4. Filtration. The water collected after loading is then passed through sand filters that separated a number of insoluble impurities. The impurities being bigger in size get collected in the pores of sand filters and clean water passes out.
5. Chemical Disinfection. The water might contain certain micro-organisms that may cause many diseases like jaundice, cholera etc. therefore, water is mixed with chemicals like chlorine or treated with ultraviolet radiations or ozone's to kill the germs present in water

             The disinfected water is then supplied into the consumer's home.
This is how we get our daily supply of water. But all the filters need to be cleaned properly, otherwise the pores get choked and hence, the level of purification decreases. A filter that cannot be cleaned must be changed. Safe drinking water must be used for maintaining a healthy life.