Pioneering development set to increase food waste recycling in the UK
The UK’s first commercial small scale anaerobic digestion (AD) system for localised food waste treatment which creates power, heat and biofertiliser has been unveiled. It has been designed to speed up the adoption of AD food waste treatment plants in the UK by making them commercially viable and thereby increasing recycling rates for municipal and commercial food waste across the country.
Currently a very small percentage of all food waste in the UK is recycled through anaerobic digestion, instead going to landfill, composting or incineration.
Burdens is set to roll out the pioneering compact food waste treatment plants following extensive trials of a demonstrator in South West Wales, which is now accepting waste from Carmarthenshire Council and HRH Prince Charles’ estate in Wales. Each system will be capable of handling between 3,000 and 5,000 tonnes of food waste per year. Currently a significant proportion of the 19m tonnes of municipal, commercial and industrial food waste, which is generated by homes, retailers, catering operations and food manufacturers, is not recycled. This presents significant opportunities to increase recycling rates and reduce emissions in line with Government and EU targets.
There are only three dedicated AD food waste treatment plants in the UK recycling municipally sourced food waste out of a total of 32, including Burdens pilot site at Llangadog in Carmarthenshire, which will become the company’s first treatment site for domestic waste. The others treat other types of food wastes from catering outlets, food retailers and manufacturers. Apart from the Burdens plant, the other AD operations are significantly larger and perform a central waste treatment function rather than a local service.
The new compact process is being targeted at private waste collection companies, in house waste management operations of local councils and those companies in the food chain, such as retailers, food manufacturers and catering providers.
Burdens is offering a fully funded solution for the modular waste treatment plants, as well as an option to buy outright.
The fully funded package will involve the company paying its customers to run the operations. In addition, Burdens will provide a full maintenance programme and pay rent for the land on which it will be located. In return, Burdens will benefit from the Feed in Tariff and Renewable Heat Incentive linked to the renewable energy outputs of the recycling process.
In addition to a fully funded solution, there is an option for customers to invest in the compact AD plants. Full turnkey plants will start from £750,000 up to £2m and provide a rapid payback through revenues gained from the gate fee, as well as the energy generated.
It is the first digester of this size to be Animal By Products Regulations (ABPR) compliant, which means that it can recycle general food waste, including meat. It also meets compost, soil and land use regulations (PAS100, PAS110). The biofertiliser generated is used as a beneficial fertiliser on local farm land.
Paul Thompson, Head of Policy at the Renewable Energy Association, said: “It is becoming clear that AD has substantial potential in the UK and that developing the technology at a smaller scale is a key part of this. The REA is a strong supporter of the opportunity for community focused anaerobic digestion. The benefits of local processing of food residues extend beyond renewable energy supply and includes local jobs, community engagement and less transport of waste over long distances.”
Added Will Kirkman, Head of Environmental Projects at Burdens: “We have set out to make small scale food waste treatment financially possible. There are a lot of misconceptions about the viability and benefits of reducing the size of AD plants to such a small scale. To date this has held back this sector of the market and arguably the recycling of food waste in the UK as larger planned facilities have often been stifled by breakdowns in contract negotiations, the inability to secure reliable feedstocks and planning requirements.
“Now for the first time in the UK we can actually show commercially viable plants in action, clearly demonstrating the benefit of locally-based solutions. This should go a long way to removing misplaced concerns about smaller scale AD food digesters, help increase uptake and consequently improve recycling rates of municipal and commercial food waste”
“Our small scale plant will offer a range of benefits to our customers. It will enable them to divert food waste from landfill and avoid related landfill taxes; create local jobs; reduce disposal costs; generate on site power and heat; and lower their emissions.
“Small scale AD operations provide for a much more sustainable operation as domestic and commercial food waste can be treated close to its source, rather than being transported many miles to a larger central facility. Its size makes it ideal for installing on existing permitted sites such as Civic Amenity and waste transfer sites, food retail distribution centres and food production premises. Also for new sites planning requirements will be minimal compared to larger scale operations.
“Our fully funded model presents an opportunity for our customers to benefit from a “no capital outlay” solution and they can run the facility themselves. The savings and generation revenues that they benefit are likely to offset all operational costs. All we require in return is a commitment to provide the land to site the facility and the feedstock for the process. For those who want to buy our system outright it presents a quick payback solution through the significant operational savings, as well as revenues from energy generation and gate fees.”
Extensive trials of the AD plant have been carried out over a two year period at a demonstrator operation in Llangadog, South West Wales. In addition, Burdens has established a track record in the design and delivery of small scale digesters in the prison service with the latest plant at HMP Oakwood being commissioned. This has proven that the separated hydrolysis technology works very efficiently at a smaller scale and is capable of generating between 20kWe-150kWe electricity per annum plus heat and up to some 100 tonnes of beneficial solid biofertiliser.
The Burdens patented digestion process involves all food waste passing through a macerator and chopper pump before feeding into holding tanks. After a three day hydrolysis and pasteurisation period, the contents of the tanks are emptied. At this stage the high fibre content is screened off and the remaining liquid or ‘soup’ is pumped into the main digester.
The biogas production takes place in the main digester, which is constantly being replenished by the input of new food waste. Liquid from this tank is recirculated to wet down the arriving food waste, with the surplus expended liquid used as a beneficial biofertiliser. The recirculation of liquid within the process ensures very high levels of heat efficiency minimising heat demand from the process. With a new and original twist developed especially for this type of plant, the separated high fibre material (mainly lignin) is combined with waste wood to produce a high quality low ash pellet for wood burners. The biogas produced in the digester is stored ready for use within the site generator, which can supply electricity and heat to be used as required.
As part of the development programme, Burdens has widely consulted with a number of organisations and Government departments including: Defra, DECC, WRAP, the National Industrial Symbiosis Programme, the Renewable Energy Association, the National Non-Food Crop Centre, the Country Landowners and Business Association, the London Waste and Recycling Board, the London Community Recycling Network and the Royal Agricultural Society of England.