Question
Biology Question on Microbes in human welfare
In domestic sewage, impurities in the form of suspended solids, colloidal materials and dissolved materials, are about
A
0.001
B
0.021
C
0.05
D
-0.1
Answer
0.001
Explanation
Solution
A mere 0.1% impurities make domestic sewage unfit for human use. These impurities include suspended solids (e.g., sand, silt and clay), colloidal material (e. g., Faecal matter, bacteria, cloth and paper fibres) and dissolved materials e.g., nutrients (nitrate, ammonia, phosphate, sodium, calcium, etc.).