Find out what happens to your food waste once it has left your home.
We collect about 12 articulated lorry loads per month, which is about 250 tonnes. After 'bulking up' your food waste is taken to the Anaerobic Digestion (AD) facility near Basingstoke. This plant uses the AD process to divert organic waste from landfill to create renewable energy.
What is AD?
AD is a series of natural biological processes whereby organic waste material - known as feedstock - is broken down by micro-organisms and converted into energy, known as biogas (a mixture of carbon dioxide and methane).
Delivery at the plant
- The organic matter delivered to the facility is weighed at the weighbridge
- Lorries tip their load into a designated tipping area
- All received material is inspected and any unsuitable items will be removed before the organic matter is sent to the digesters
The digestion process
- The organic matter is shredded and fed into the digestion process. From this point forward, it is entirely contained within sealed pipework and tanks
- The digesters are completely sealed to create an oxygen free environment needed for the process bacteria to thrive
- This also means that this part of the process is completely dust and odour free
- Each digester is fed by a pumped pipework system
- Within the digestion tanks, material is digested at around 55°C to produce biogas and a compost-like product
- The digestion process takes around a month; after which the gas will be extracted from the waste
After digestion
- The material is pasteurised to ensure that all pathogens and undesirable bacteria are killed
- At the end of the process a highly nutritious and safe product remains, known as digestate
- The entire process is monitored, tested, controlled and optimised using a range of sensors within each stage of the process
Extracting the biogas
- Biogas produced from the digestate process is extracted from the top of each digester and taken to a Combined Heat and Power (CHP) unit, where it is used to generate renewable energy
- The CHP unit consists of a gas engine connected to an electrical generator, which sits inside a noise insulated containerised unit
- This process generates heat, which is captured for use on site for space heating or in neighbouring buildings
How much electricity is generated?
The electricity generated provides on-site power required for the plant, with the majority sent to the local electricity network.
The Basingstoke AD facility generates 1.5 MW of electricity, enough to power as many as 3,000 UK homes, by processing up to 40,000 tonnes of food waste per year which would otherwise go to landfill.
At the end of the process
A stable, nutrient-rich biofertiliser is created. The process meets stringent requirements for the production of quality biofertiliser from Anaerobic Digestion, including those required by BSI PAS110, the Environment Agency and ABPR (Government regulations for animal by products).