Nestlé was interested in the technology after seeing a demonstration plant at BV Dairy in Shaftesbury, Dorset, designed by Clearfleau and built with finance from the Environmental Transformation Fund (ETF), administered by WRAP (Waste & Resources Action Programme), as part of a Government initiative to promote AD.
Richard Gueterbock, co-founder, Clearfleau, told FoodProductionDaily it dissolves processing residue from Nestlé, such as ingredients that have passed their sell-by-date, starch for molding confectionery, and leftover and unsold products that are misshaped or mispacked, into a ‘chocolate soup’ that is fed into a digester to reuse as biogas.
“The technology we use is adapted to each manufacturer. The cost varies between £1m to £2m depending on the size of the plant and the complexity of the project,” he said.
“Previously, production residues from Fawdon, the former Rowntree factory, were discharged to the sewer or fed to pigs but the water would contain fats and sugar pumped from the factory and they were not going down the drain properly. Now, bio-degradable production residues are converted into renewable energy on the factory site.”
The plant, which was installed last year, converts 200,000 litres a day of feedstock into renewable energy from wash waters from the site and 1,200 tonnes of residual bi-products and ingredients.
The biogas produced fuels a combined heat and power (CHP) engine, which produces 200kW of electricity, used in the confectionery production process. This is about 8% of the factory’s power requirements, cutting the annual electricity bill by about £100,000 a year.
Feed in Tariff
In addition, the site has registered for the Feed in Tariff, and will receive annual payments of about £250,000 a year.
“Unlike a conventional treatment plant, we are generating energy saving on costs and the disposal of material. On top of that, there are Government incentives for generating renewable energy. We are selling an effluent treatment plant that will provide a return on investment within five years,” added Gueterbock.
Inder Poonaji, head of sustainability, Nestlé, said it chose Clearfleau because it could meet the firm’s specific needs and designed a compact plant to fit on the edge of the factory car park.
“The carbon footprint for anaerobic digestion is at least seven times smaller than for conventional aerobic treatment plants,” he said.
“On-site treatment of production residues will help us reduce the wider environmental impact of our business and meet our sustainability goals.”
Diageo whisky distillery
Gueterbock added the company, which is based in Bracknell, Berkshire, employs 25 people and has installed five plants including a Diageo whisky distillery in Scotland.
“We are now looking at projects in Germany and Northern Ireland next year but we have to focus on our home market first as we slowly expand into this niche sector,” he said.
The firm is also refurbishing its mobile trial unit to demonstrate to food processors.
“Our priority is to focus on the AD plants that have been commissioned and get them up and running in the New Year,” added Gueterbock.
“We have to provide a way of building these sites that is not intrusive and does not affect the work flow of the factory. AD plants are the plants of the future for F&B manufacturers.”