Berkshire, UK based anaerobic digestion specialist, Clearfleau , is commissioning the first plant to supply the UK gas grid with biogas generated purely from cheese production waste.
The company said that the facility, located in rural Cumbria, is its most complex plant to date and will feed biomethane into the gas grid.
According Clearfleau , by feeding the biomethane into the grid, the facility will generate over £3 million per annum in cost savings and revenue, while supplying up to 25% of the creamery’s energy requirements.
The plant has been designed and built for Lake District Biogas, which will operate the site for 20 years taking feedstock from First Milk’s Aspatria creamery site.
First Milk is a dairy company owned by family farms which supply it with fresh milk. In turn it supplies cheese, dairy products and ingredients to the retail and food service markets in the UK and internationally.
The feedstock was said to comprises low-strength wash waters such as process rinses, supplemented by whey permeate (cheese production residue after protein extraction for use in energy supplements), which is pumped to the AD plant from the creamery.
The liquid is then pumped into the AD plant from the creamery where the bugs convert the fats and sugars in the feedstock into biogas.
This is stored in the gas dome before being upgraded to bio-methane - 80% of the biogas is fed to a membrane based upgrade unit that removes carbon di-oxide from the gas to produce bio-methane with a comparable thermal value to North Sea gas (some biogas is also fed to a CHP unit to provide power to run the treatment plant).
He company claimed that this is the first on-site Anaerobic Digestion (AD) plant in the dairy industry in Europe to inject biomethane generated exclusively by digesting its cheese making residues into the gas grid,.
Once operating at full capacity later this Spring, the plant is expected to treat 1650 cubic metres of process effluent and whey per day and generate around 5MW of thermal energy.
It is also expected to produce 1000 cubic metres of biogas per hour, of which over 80% will be upgraded for injection into the national grid. At least 60% of the biomethane will be used in the creamery for steam generation, with the balance being used by local businesses and households in Aspatria.
Downstream treatment will take place in an existing aerobic plant which Clearfleau has upgraded and enhanced through provision of chemical treatment for nutrient removal.
According to the company, this upgrade will allow First Milk to significantly reduce levels of phosphate in its effluent, which is discharged to the River Ellen. Supported by the Environment Agency, is expected to ensure an early delivery of new tighter discharge standards, which are required by the Water Framework Directive.
Clearfleau’s added that its on-site AD technology is proven to reduce the Chemical Oxygen Demand (COD) of the production residues by at least 95%. Aerobic polishing will then remove residual COD and nutrients (nitrates and phosphates) to allow safe river discharge.
The residual sludge from the plant will be spread on local farmland as a nutrient rich soil improver.
Revenue benefits were said to include 20-year index-linked, government-backed incentive payments, with about £2 million per annum in support through the government’s RHI scheme and a further £1 million through the sale of gas to the wholesale market and from the Feed in Tariff scheme for the power generated in a Combined Heat & Power generator.
The new anaerobic digestion plant will take over from the older aerobic plant. Clearfleau said this will have saved First Milk from having to upgrade the old inefficient plant, reducing their effluent treatment costs and carbon footprint, while cutting operational costs, which are borne by Lake District Biogas.
Lake District Biogas is a development company set up to facilitate the design, construction, commissioning and operation of the on-site AD plant at the Aspatria site. The company has raised the finance to fund the project and will supply an on-going service to the First Milk site, working with Clearfleau and other specialist technology suppliers.
Additional benefits from the deployment of on-site digestion in the dairy processing sector were said to include reduced energy and off-site disposal costs.
Food for Thought
According to Clearfleau’s the food industry is increasingly realising the contribution production residues can make to the circular economy.
The company noted that following the recent Paris Climate Change Summit, CEO’s of global food companies including Unilever and Nestle stated: “We want the facilities where we make our products to be powered by renewable energy with nothing going to waste.”
Gordon Archer, chairman of Lake District Biogas commented: “Completion of this £10 million project on time, given the weather conditions in Cumbria this winter, has been a major achievement.”
“This is the largest AD plant on a dairy processing site in Europe dedicated to handling the residual materials from the cheese making process,” he continued.
Craig Chapman CEO of Clearfleau Limited said: “Dairy processors can generate value from their residues with a better return on investment than for other more conventional treatment and disposal options.”
“This project, generating biogas solely from creamery residues is based on British engineering and is transforming the way in which the dairy industry manages its residues” he added.
“This shows how sustainability can be an integral part of our food supply chain. We are looking at other dairy projects as more companies realise the energy potential of their residue,.” Concluded Chapman.
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