Step 1
Waste Removal
At this stage we collect food waste from food producers and local councils.
Step 2
Food processing
Food waste goes into our plant and is converted to energy and digestate via anaerobic digestion.
Step 3
Energy production
Here the waste gases from the digestion process are used to power turbines that produce electricty.
Step 4
Bio-fertiliser spreading
Finally, the Bio-fertiliser produced from our plant is used to fertilise land.
Food Waste from Food Manufacturers and Waste Contractors
The first step in the process is receiving the feedstock for our plants. Our clients vary from big national organisations through to local dairies, cider mills and local authorities. Last year we processed around 67,000 tonnes of waste through our Holsworthy plant alone.
Read moreThe Logistics of Food Waste
The waste is delivered to our sites from all over the country and we endeavour to keep the food miles as low as possible by managing the waste at our nearest plant to the source of production.
Read moreThe start of the process
After the waste has been delivered to site it enters the process in a variety of ways. Packaged waste is fed into a machine that separates the packaging from the food. The packaging is then recycled if possible and the food is mixed to together with other waste streams in a tank.
Read moreMaking the feedstock
The waste is then mixed together in our mixing tank to turn it into a pumpable soup. This process also helps to blend the varieties of substances found in the food waste into a more homogenous material.
Read moreEnsuring Quality Feedstock
This important part of the process allows us to accept animal by-products such as fish and abattoir waste. The macerator ensures any that food particles in the ‘soup’ are reduced to below 12mm ensuring that it can be fully heated in the next stage of the process.
Read moreKilling Unwanted Bacteria
The food waste is heated to 70°C for one hour to ensure all pathogens including as E-Coli and Salmonella are killed and can’t spread throughout the material. This process also helps us to heat up the feedstock so that the digesters are at the right temperature, 38°C, to produce the biogas.
Read moreProduction of Biogas
Following pasteurisation, food waste is pumped into one of our digesters, these are large tanks that hold thousands of tonnes of food waste at a time. The digesters contain cultures of anaerobic bacteria that digest the waste, the digestion process results in the production of biogas which is around 60% methane and 40% carbon dioxide. This process takes up to two months, so that the maximum amount of energy can be extracted.
Read moreStoring Digestate – A Liquid Fertiliser
The digested material is pumped from the digesters into a storage tank ready to be used as a liquid fertiliser. The digestate is passed through a screening machine that removes any residual inorganic material such as plastic or grit which can’t be digested. This ensures are digestate qualifies as a biofertilliser under the PAS 110 scheme.
Read moreStoring Renewable Energy
The biogas that is produced through anaerobic digestion process is stored on domes on top of the digesters and in a 5000 m3 biodome. This storage system allows us to use the gas when we want meaning we can produce power when people need it. This is a huge advantage over other renewable system that can’t efficiently store energy and can only produce power when the elements determine so.
Read moreEnergy Production
The energy stored in the biogas is converted into electricity and heat by using it to run a combined heat and power (CHP) internal combustion engine. At our Bishops Cleeve facility we use state-of-the-art gas upgrading equipment to create biomethane for the local gas network. Some of the electricity produced is used to run the plant but most of it is exported to the National Grid. The heat captured from the engines is used to run processes such as pasteurisation and heats our sites’ hot water.
Read moreDigestate – A liquid Fertiliser
Digestate is nitrogen rich bio fertiliser which is spread to land as a replacement for mineral fertilisers. Its use ensures that vital nutrients in the food waste are recycled and returned to land.
Read moreStep 1. Waste removal / collection
The first step in the process is collecting ‘fuel’ for our plant. This comes in the form of food waste from industry, council collections or local businesses.
FOOD WASTE FROM FOOD MANUFACTURERS AND WASTE CONTRACTORS
The first step in the process is receiving the feedstock for our plants. This comes in a variety of forms and can include anything from pasties to fish heads. Our clients vary from big national organisations through to local dairies, cider mills and local authorities.
THE LOGISTICS OF FOOD WASTE
The waste is delivered to our sites from all over the country, we endeavour to keep the food miles as low as possible by managing the waste at our nearest plant to the source of production. We collect the food waste using our own transport or through partnerships with several national haulage companies.
Step 2. FOOD PROCESSING USING ANAEROBIC DIGESTION
Now that we have our ‘fuel’ we need to refine it so that we can power our engines.
THE START OF THE PROCESS
After the waste has been delivered to site it enters the process in a variety of ways. Packaged waste is fed into a machine that separates the packaging from the food. The packaging is then recycled, if possible and the food is mixed together with other waste streams in a tank.
Receiving the feedstock
The waste is then mixed together in our mixing tank to turn it into a pumpable 'soup'. This process also helps to homogenise the waste.
Preparing the Feedstock
This important part of the process allows us to accept animal by-products such as fish and abattoir waste. The macerator ensures any that food particles in the ‘soup’ are reduced to below 12mm ensuring that it can be fully heated in the next stage of the process.
Killing Unwanted Bacteria
The food waste is heated to 70°C for one hour ensuring all pathogens are killed. This process also helps us to heat the feedstock so that the digesters are at the right temperature, 38°C – 40°C, to produce the biogas.
Production of Biogas
Following pasteurisation, the food waste is pumped into large tanks called digesters. The digesters contain cultures of anaerobic bacteria that digest the waste over a period of approximately 55 days. The digestion process results in the production of biogas which is around 60% methane and 40% carbon dioxide.
STORING BIO-FERTILISER
After 55 days the digested material is pumped into a storage tank ready to be used as a liquid fertiliser. The bio-fertiliser is passed through a screening machine that removes any residual inorganic material such as plastic or grit which can’t be digested. The biofertilliser is totally free from pathogens and contains high quantities of nitrogen, potassium and phosphate; all vital nutrients for plant growth.
Step 3. Energy production
Storing Renewable Energy
The biogas that is produced through the anaerobic digestion process is on site. The storage system allows us to use the gas when required meaning we can produce power when people need it. This is a huge advantage over other renewable systems that can’t efficiently store energy and can only produce power when the elements allow.
Energy Production
The energy stored in the biogas is converted into electricity and heat or biomethane. Some of the electricity produced is used to power the plant but most of it is exported to the National Grid. The heat is used to run the process such as pasteurisation and to heat on site water. Biomethane is injected to the local medium pressure grid, and used by local consumers in place of natural gas.
Step 4. BIO-FERTILISER
Spreading the BIO-FERTILISER
Our bio-fertiliser is spread to land as a replacement for mineral fertilisers. Its use ensures that vital nutrients in the food waste are recycled and returned to the ground.