Anaerobic digestion
Anaerobic digestion is a process that breaks down organic matter (things like food waste and manure) without the need for oxygen. To do this, special bacteria are used that can only survive in oxygen-free environments and they eat the organic matter, breaking it down and producing gas (mostly methane and carbon dioxide) as a result. This gas can be used to heat homes or can be turned into electricity, plus the leftover material that is left after digestion is a useful natural fertilizer for plants.
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