Clearfleau commissions AD facility at UK creamery

By Clearfleau | April 14, 2016

Clearfleau, a leading British provider of on-site treatment solutions for the food and beverage sector, is commissioning its most complex plant to date, which will feed biomethane into the gas grid in rural Cumbria. By feeding the biomethane into the gas grid, the facility will produce over £3 million ($4.25 million) per annum in cost savings and revenue, while supplying up to 25 percent 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. This comprises low-strength wash waters such as process rinses, supplemented by whey permeate (cheese production residue after protein extraction for use in energy supplements).  This is pumped to the anaerobic digestion (AD) plant from the creamery.

This is the first on-site AD plant in the dairy industry in Europe to feed biomethane to the gas grid, generated exclusively by digesting its cheese making residues. When the plant is operating at full capacity later this spring, it will treat 1,650 cubic meters per day of process effluent and whey and generate around 5 MW of thermal energy.

It will produce 1,000 cubic meters of biogas per hour, of which over 80 percent will be upgraded for injection into the national grid.  At least 60 percent of the biomethane will be used in the creamery for steam generation, with the balance being used by local businesses and households in Aspatria.

Revenue benefits 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 the CHP engine.

The new plant, with its state of the art British technology, will take over from the outdated aerobic plant. 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. Additional benefits from the deployment of on-site digestion in the dairy processing sector include reduced energy and off-site disposal costs.   

Clearfleau’s unique process takes the feedstock from the Aspatria creamery site, comprising low-strength wash waters such as process rinses, supplemented by whey permeate (cheese production residue after extracting protein used in energy supplements).  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 percent of the biogas is fed to a membrane based upgrade unit that removes carbon dioxide 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). 

The food industry is now realizing the contribution production residues can make to the circular economy. After 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 says: “Completion of this £10 million project on time, given the weather conditions in Cumbria this winter, has been a major achievement for the project team and Clearfleau.  This is the largest AD plant on a dairy processing site in Europe dedicated to handling the residual materials from the cheese making process and we look forward to working with Clearfleau on future projects.’

Craig Chapman, CEO of Clearfleau Ltd., says, “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.  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 residues.”

As an initial step, Clearfleau refurbished the existing aerobic plant to enable First Milk to significantly reduce levels of phosphate in their effluent, which is discharged to the River Ellen.  Supported by the Environment Agency, this will ensure an early delivery of new tighter discharge standards, which are required by the Water Framework Directive. 

Clearfleau’s on-site AD technology is proven to reduce the chemical oxygen demand (COD) of the production residues by at least 95 percent.  Aerobic polishing will then remove residual COD and nutrients (nitrates and phosphates) to allow safe river discharge.