Question

What should be the ratio of raw material to water?

(a) 1:1

(b) 4:1

(c) 5:2

(d) 3:6

I have been asked this question in a job interview.

Question is taken from Problem involved in Biogas Production in chapter Biomass Energy of Energy Engineering

Answer 1

Correct option is (a) 1:1

For explanation I would say: Experience has shown the raw material (domestic and poultry wastes and manure) ratio to water should be 1:1, i.e., 100kg of excrete to 100 kg of water. In the slurry, this corresponds to a total solids concentration of 8-11 per cent by weight.