Tuesday, April 21, 2015

Clever Re-use of Pre-cast Concrete in World War II Hangar for AD Plant Feed Storage

Whites Concrete has recently provided an innovative storage solution for the "Northern Crop Driers" Anaerobic Digestion Plant, and we think that the way in which this new use has been found for a historic World War II aircraft hangar, will interest many people.

Based south east of York at the former RAF Melbourne, Northern Crop Driers has successfully utilised pre-cast panels from Whites Concrete to maximise silage storage for its AD plant. 
Leading manufacturers of dried grass horse feeds that are virtually identical to fresh grass, Northern Crop Driers needed a clamp capable of storing 6,000 tonnes of silage in an old hangar at its Melrose Farm base. With a roof height limiting the maneuverability of machinery to compress the stored material, 
Whites Concrete were called upon to create a design that would use the space to full effect, keeping silage dry and clean whilst ensuring that load demands would meet the bulk density. The safely stored maize, grass silage (plus some sugar beet), and slurry from sister company Melrose Pigs, provides feedstock for the 500kW AD plant. 
Pam Dear from the family-owned and run business said: “Investing in an AD plant made perfect sense here because it brings everything together.
With our pigs and grass drying business, we knew we could generate our own green electricity, but first we had to bring in a whole year’s worth of crop, so getting our storage facility right was crucial”. 
Whites Concrete worked closely with Northern Crop Driers to initially provide two designs, including one with metalwork, but 4m concrete panels were ultimately chosen as the best solution. Pam Dear added: “We were determined to utilise every inch of the hangar to give us 6,000 tonnes of storage, so Whites’ expertise in materials and load-bearing requirements was invaluable”. 
Over a period of one month, 150No 4m high (1m wide) Whites Concrete panels were installed at the 750-acre Melrose Farm, where grass, home grown maize and supplies from neighbouring farms combine with the pig slurry to produce enough power for everything required on site, with excess sold on to the grid. L-shape Groundwall panels from Whites Concrete were considered the most suitable option so as not to create any additional load bearing onto the existing structure of the old hangar. 
Ideal as push-walls to resist machinery loads, extreme heights of storage and areas where heavy traffic will be working, Groundwall is hygienic, as well as far quicker and more economical than block or in-situ concrete. 
Pam Dear continued:
 “Despite being a higher cost, the pre-cast concrete panels from Whites Concrete are actually much cheaper to install. We produce high quality horse feed from 100% natural, home grown grass, which takes up a good chunk of power to dry out, so in the not too distant future we also hope to harness the heat from our AD plant for that part of our business. Going into AD production has given us more stability. It is helping both of our businesses grow and shows that we are serious about sustainability”. 

The high quality of the digestate at Melrose Farm is also proving a winner, with its valuable nutrients producing healthier grasses. It has helped make a big reduction on bought-in fertiliser. Following the success of the silage clamp, 
Northern Crop Driers has since extended the storage facility by an additional 4,000 tonnes, installing a further 90 No 3m high pre-cast concrete panels from Whites Concrete to create 10,000 tonnes of silage space for the AD plant. 
These extra panels are from Whites Concrete’s Rockwall range, which achieves a finished concrete strength in excess of 60N for any above or below ground construction.
 “Moving into AD is a very good fit with our business model”, concluded Pam Dear.
“We produce 100% natural horse feeds and bedding, and now we generate our own on-site green power, with a payback of just five to six years”. 
Historical Note:  RAF Melbourne was a Royal Air Force station during the Second World War. In the late 1940s the airfield was used by Armstrong Whitworth Whitleys of 10-Squadron as a relief landing ground for RAF Leeming near Northallerton, just south of Darlington. The squadron continued with operation until March 1945. 
 It lost 109 aircraft. Unusually, Melbourne was equipped with FIDO (Fog Investigation and Dispersal Operation). This made the RAF station a popular diversion airfield for other squadrons returning from operations to Yorkshire. The [smoke making] device consisted of two pipelines situated along both sides of the runway, through which fuel was pumped, and then out through burner jets positioned at intervals.
Although very large volumes of fuel were consumed, FIDO more than made up for the costs involved by reducing aircraft losses
This very much follows the ethos of Anaerobic Digestion. Re-use of existing facilities certainly avoids carbon emissions, and in this case the solution chosen also avoids changing the historic structure, by any more than is essential. Well done, Northern Crop Driers, and Whites Concrete!

Tel: 01924 464 283
k whites[@]longley.uk.com
Ravensthorpe Road, Thornhill Lees, Dewsbury, West Yorkshire, WF12 9EF

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