How Anaerobic Digestion works
The process of Anaerobic Digestion is relatively simple, but highly effective. Anaerobic means without oxygen, so this is an oxygen-less process that happens in airtight sealed containers.
STEP 1: All of the feed stock (including food waste, crop residues, slurry and manure) is placed into buffer tanks and mixed into a thick ‘soup’.
STEP 2: The ‘soup’ is then pumped into different temperature controlled vessels known as digesters.
STEP 3: Inside the digesters a number of naturally occurring bacteria digest the ‘soup’, releasing a mixture of gases, collectively known as Biogas.
STEP 4: Biogas is 60% methane and 40% carbon dioxide, with small traces of contaminant gases such as hydrogen sulphide and ammonia. We remove the carbon dioxide and contaminants from the Biogas, leaving pure methane – a renewable natural gas that can be burned to provide heat, electricity or road fuel.
STEP 5: The undigested remains of the ‘soup’ and dead bacteria are called Digestate, and are rich in key plant nutrients such as nitrogen, phosphate and potassium. The Digestate is pasteurised to kill off any harmful bacteria, leaving a wonderfully rich, organic fertiliser and compost.