Question
Biology Question on Environmental Issues
What percentage of impurities make domestic sewage unfit for human use?
A
0.01
B
0.001
C
0.0001
D
0.00001
Answer
0.001
Explanation
Solution
Domestic sewage consists of everything that passes into sewer from residential areas i.e., human excreta, food residue, detergents, etc. Only 0.1 % of municipal waste water consists of sewage impurities. The rest 99.9% is water. Sewage contains pathogens too.