Question

Presence of carbonaceous matter in the sewage

a) Causes reduction in its dissolved oxygen content thereby endangering the life of aquatic creatures

b) Reduces sulphate ions to sulphides causing obnoxious smell

c) Increases the quantity of chlorine used for its purification

d) All a), b) and c)

Answer 1

Presence of carbonaceous matter in the sewage Causes reduction in its dissolved oxygen content thereby endangering the life of aquatic creatures, Reduces sulphate ions to sulphides causing obnoxious smell and Increases the quantity of chlorine used for its purification