Question

What is the dose of lime required in the excess lime treatment?

(a) 10-20ppm

(b) 0-10ppm

(c) 5-10ppm

(d) 5-20ppm

I got this question in a national level competition.

I want to ask this question from Methods of Disinfection in section Properties of Disinfection of Environmental Engineering

Answer 1

Correct answer is (a) 10-20ppm

The explanation is: The dose of lime used in the excess lime treatment is 10-20ppm and the excess lime can be removed by the process of re-carbonation.