What is an inoculum, and why does a new digester need one?

An inoculum is a starter culture of active anaerobic microbes, usually digestate or slurry from a running digester, or cattle dung. Without seeding, a new digester can take months to establish stable methanogenesis, so the inoculum is what shortens the start-up lag.

derived

Reasoned from sourced facts or engineering fundamentals, not quoted from one.

Level

Beginner — New to biogas. Plain language, no units assumed.