Anaerobic digestion
A managed biological process that breaks down organic material without oxygen.
Example
Digesters can process food waste or manure to produce biogas and digestate.
The catch
Leakage and digestate handling influence the overall environmental result.
Related terms
Biogas, Leakage, Anaerobic decomposition, Biomethane, Composting, Destruction efficiency
In more depth
Anaerobic digestion, explained.
Anaerobic digestion is the controlled version of the rotting that happens inside a landfill, run in sealed tanks so the methane can be caught and used. Microbes work through the feedstock over a period of weeks, usually in heated vessels. The gas can be burned on site for heat and power or cleaned into biomethane, and the residue can return nutrients to farmland in place of synthetic fertiliser.
The climate case depends on what the plant replaces. It scores well for food scraps kept out of landfill, and for the fossil gas and factory-made fertiliser its products displace. Crops grown only to feed a digester raise their own land and emissions questions. The waste hierarchy still ranks preventing food waste above digesting it.