AD adds up for Cannington as Landia’s pumps help food waste-to-energy business to expand
As potato and arable crop farmers who diversified into cold storage, bioenergy and recycling, Mike and Tim Roe’s pioneering journey into Anaerobic Digestion shows what can be achieved by operating the very best in pumps and systems.
The father and son team, who are based in the South West of the UK in Bridgwater, Somerset, first ventured into cold storage in 1997, growing their business from around 200 pallets of cheese and fruit juice to over 3500 pallets stored per week. This success brought about the need to move to a much larger site, which took place in 2003, with today in excess of 10,000 tonnes of fruit juice and food ingredients stored at -14C to ambient temperatures. Not surprisingly, these quantities led to much higher energy bills, which as with the global trend, have been rising steadily, year-in, year-out.
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“Addressing an annual electricity bill in the region of a quarter of a million pounds became a big priority”, said Tim Roe, Managing Director at Cannington Enterprises, the parent company of Cannington Cold Stores, Cannington Bio Energy and Cannington Recycling Services.
“We thought there had to be a way of generating electricity from our farm land. Agricultural commodity prices were very low at the time and wind/solar tariffs weren’t around. Facing an energy gap, we had to do something, so we decided to take charge of our own destiny by building an Anaerobic Digestion (AD) plant”.
Tim remembers that with little AD knowledge around in the services industry, planning in 2008 proved pretty fraught to say the least. He says that people tended to form their own ‘uninformed opinions’ – and still do to some extent. When planning did go through, Tim and Mike initially installed two digesters (a third six months later) in 2009, using corn silage from their farm as feedstock, plus some limited liquid waste.
‘Flexibility for different feedstocks’
“At first we were producing around 700kW”, added Tim, “which was certainly encouraging against the 300kW of power needed at the time to run the site. We designed our process so that it would have the flexibility for different feedstocks, installing a Landia POP-I mixer at the front end to keep solids in suspension for the main reception tank, and later a submersible Landia chopper pump feeding out of that into a feedstock holding tank. We’ve always been willing to test different pumps, so this Landia unit actually replaced our initial choice (from a different pump manufacturer), which proved ineffective in handling the corn”.
‘Chopper Pump has accelerated batch times’
Cannington’s AD process was working more than adequately, but in 2011 Tim and Mike chose to raise the stakes by switching exclusively from corn to food waste, which decomposes twice as quickly to produce the all-important gas much faster. They installed two additional CHP engines to boost AD output to 1.3MW. Food waste now arriving at Cannington is shredded and de-packaged before liquids are added en route to the reception tank where the Landia POP-I mixer first handles the material (17-20% dry matter content).
Unlike many other biogas operations, there is a post-pasteurisation process at the end of the system, whereby organic waste must be heated to 70 degrees for at least one hour. For Cannington’s pasteuriser there is also a wall-mounted POPTR-I mixer that Landia managed to install using the existing man-way, which removed the need for any additional refurbishment work. There is also a dry-mounted high-pressure Landia MPTK-I chopper pump from Landia that has proved a key part of the operation by significantly accelerating batch times.
Tim Roe continued: “The first pump we had could manage the 35-metre head required to make the final discharge to our digestate lagoons, but it would take 24 hours and suffer from significant wear and tear. The Landia MPTK chopper, which also has to pump 250m horizontally as well as 35m vertically, is far more resilient and does the same job in just two and a half hours, which has created major benefits all the way back down the production line”.
Cannington have carried out 99 per cent of the AD work themselves, making considerable savings and allowing fine tuning to their own particular requirements. Over 600,000 tonnes of dirt has been moved to facilitate the AD plant, which is very well screened from the road.
From truckloads of bulk material from food processors to collecting single wheelie bins form schools, restaurants and pubs, Cannington now process 60,000 tonnes of food waste pa. The company’s flexibility and willingness to help as an almost third party disposal/recycling center has created very good relationships with an increasingly wide customer base.
Income from waste and the AD-generated electricity that’s sold onto the UK’s National Gird now accounts for about half of Cannington’s income. 2.3MW is generated, with around 1.35MW exported to the grid after approximately 700kW is used to power the site. But it doesn’t end there.
“By the end of this year we will have a further three digesters”, added Tim. “These will mainly be for storage to stabilise and strengthen the quality and quantity of our continuous process – and we can also harness more gas from them.
Digestate from the end of the AD process also presents Cannington Enterprises with opportunities beyond renewable energy generation, with Tim and Mike, ever looking for improvement, hoping to set up their own on-site laboratory in the not too distant future to further monitor the quality of the final product.
‘Farmers queuing up’
“We’ve been using the digestate on our farm land to great effect,” said Tim, “but we’re now in a position where we have farmers queuing up for it because the nutrients in it make such a good organic fertiliser. This is another expanding part of our business and part of the joined up environmental thinking that we’re proud of”.
Landia
info@landia.co.uk
+44 (0) 1948 661 200
www.landia.co.uk
Landia Ltd
- 0194 8661 200
- info@landia.co.uk
- http://www.landia.co.uk
- Waymills Industrial Estate, Whitchurch, Shropshire, SY13 1TT GB
About us
Landia's headquarters are located in Lem, which is how it has been since 1933. Today, Landia has subsidiaries in England, Germany, Norway and the US, and a sales office in China. In addition, Landia products are sold in 45 countries worldwide. Landia supplies pumping and mixing solutions to many different industries, with the most important ones being agriculture, wastewater, biogas plants and the fish industry. In general, you will find Landia's products wherever there is a difficult medium to be pumped or mixed. Landia survives by selling quality solutions in close partnership with the customers.
Landia is not a supermarket where customers select products from the shelves. Our technical sales people are always in close discussions with customers, which ensures solutions that work. For Landia, quality in every phase a matter of course, and we have been ISO9001 certified since 1994. Quality also means that many of Landia's products have been in operation for 20-25 years even though the operating conditions may be extreme. In that way, Landia's customers achieve the lowest lifespan costs, while resource consumption is minimised, which further results in a positive impact on the environment.
Where we supply to
Europe, Africa, Asia, Australia, South America, North America
Industries we supply to
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