Question

How many weeks does a batch digester need to produce biogas?

(a) 1 week

(b) 2 – 4 week

(c) 12 week

(d) 4 – 8 week

I got this question by my college director while I was bunking the class.

This key question is from Anaerobic Fermentation in chapter Biomass Energy of Energy Engineering

Answer 1

Right option is (b) 2 – 4 week

To explain: Depending on the waste material and operating temperature, a batch digester will start producing biogas after 2 – 4 weeks, slowly increase in production then drop off after three or 4 months. Batch digesters are therefore best operated in groups.