Anaerobic Digestion – or AD - is the breakdown of organic materials by micro-organisms in the absence of oxygen. The process generates methane, which can be used as a fuel.
The mechanical treatment technology at Allerton Waste Recovery Park extracts organic waste (such as food and garden materials) for use in the AD facility. Previously this organic material has gone to landfill.
These items are now processed in a fully enclosed anaerobic digester to generate renewable energy.
After the generation of energy, a digestate remains. At Allerton Waste Recovery Park this digestate is used in the energy from waste facility. This is because it is not suitable as a compost because it has come from a mixed waste source.
If food and kitchen waste were to be collected separately from general waste and used in AD facilities then the digestate could be used as a compost-like material for land use.
At the moment, there are no separate food waste collections in North Yorkshire – which is why we cannot use the digestate as a compost-like material.