ICSE Class 9 Answered

What is the secondary treatment of water? What processes are required for the tertiary treatment of water?

Asked by Topperlearning User | 25 May, 2015, 11:06: AM

Expert Answer

Secondary Treatment: In this method, organic matter which is present in water is biologically degraded by micro organisms. After the primary treatment when water enters the tank, it comes in contact with micro organisms. Air is introduced into the tank through diffusers. Micro organisms in the presence of oxygen break down the organic matter and the impurities then settle at the bottom of the tank which are later removed. Then, water is treated with chlorine gas which kills the rest of the harmful organisms.
Tertiary Treatment: In this method nutrients like nitrogen or phosphorous are removed. This water can be reused for industrial, agricultural and domestic purposes.

Answered by | 25 May, 2015, 01:06: PM