Question

Match the impurities present in sewage with their types.

(i) Human faeces	(a) Inorganic
(ii) Metals	(b) Organic
(iii) Vibrio cholerae	(c) Bacteria

• A. (i) - a, (ii) - (b), (iii) - c
• B. (i) - b, (ii) - a, (iii) - c
• C. (i) - c, (ii) - b, (iii) - a
• D. (i) - c, (ii) - a, (iii) - b

Answer 1

The correct option is B (i) - b, (ii) - a, (iii) - c

Sewage is a complex mixture containing suspended solids, organic and inorganic impurities, nutrients and disease causing bacteria and other microbes.
It contains organic impurities such as human faeces and animal wastes, inorganic impurities such as metals, nitrates and disease causing bacteria such as vibrio cholerae which causes cholera.