A closed vessel or covered lagoon where microorganisms break down organic matter without oxygen, producing biogas (methane + CO₂). Mesophilic operating temperature typically ~35°C.
An anaerobic digester is a closed vessel or covered lagoon where microorganisms break down organic matter — agricultural slurries, food waste, sewage sludge — in the absence of oxygen, producing biogas (predominantly methane with CO₂). Mesophilic digestion operates at ~35°C; thermophilic at ~55°C. Floating covers on digesters and digestate storage support heat retention (reducing heating energy cost), odor capture, and partial methane release reduction.
Also known as: AD, digester