Anaerobic digestion facility for food waste
Up to 40,000 tonnes a year of food waste, mainly from homes around Surrey and also some from businesses will be treated at the Eco Park's anaerobic digestion facility.
Anaerobic digestion is a process which uses micro-organisms to break down biodegradable material – in this instance food waste – in an enclosed system in the absence of oxygen.
How does the process work?
- The food waste will go through a pre-treatment process to remove items unsuitable for the process and shred it into pieces of a similar size.
- Water will be added and the mixture will pass through a series of tanks.
- The food waste will be broken down by micro-organisms in the absence of oxygen to produce:
- A biogas, a methane rich gas which will be used to generate electricity in a gas engine and generator that will be supplied to the national grid.
- Digestate; excess water will be removed from this to create an organic, compost like material that can be used on farmland to replace artificial fertilisers.
The short animation below shows how the anaerobic digestion process turns food waste into energy and fertiliser