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url: https://www.eurocovers.eu/glossary/anaerobic-digester
term: Anaerobic digester
definition: A closed vessel or covered lagoon where microorganisms break down organic matter without oxygen, producing biogas (methane + CO₂). Mesophilic operating temperature typically ~35°C.
updated: 2026-05-25
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# Anaerobic digester

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.