Question

Why Magnesium carbonate is not commonly preferred as coagulant?

(a) It is expensive

(b) It does not remove color

(c) Formation of sludge

(d) The time required for floc formation is less

This question was posed to me in class test.

My doubt stems from Sedimentation with Coagulation in section Sedimentation of Environmental Engineering

Answer 1

Correct option is (c) Formation of sludge

The explanation is: When magnesium carbonate and lime are dissolved in water, magnesium hydroxide and calcium carbonate are formed which are soluble in water and sludge is formed in slurry form, so they are not commonly used.