Background to specification
SITA Cornwall Ltd has been responsible to managing the waste in the county since 2006. Among its operations is its Refuse Transfer Station (RTS) at Pool near Redruth, which reduces handling costs and saves the environment by enabling the bulk haulage of waste.
Here civil engineering and building contractors Dyer & Butler were commissioned to construct a new £1.7 million RTS building with the capacity for handling 70,000 tonnes of waste each year.
The project includes a new access road, groundworks, infrastructure, car park area, concrete work, landscaping and highway improvements to the local road system.
With groundworks taking place close to a live road, the efficient use of space was critical. Rather than use a crate system for stormwater attenuation and drainage, which would take up more space and be much more complex and slow to install, Dyer & Butler’s project manager Alex Gallie recommended a Tubosider system.
One of the main challenges at the site at Pool was arriving at a solution which would give a large amount of capacity – 660 cubic meters – and yet require the smallest possible excavation area to fit within the plan.
SITA at first questioned whether our large diameter steel pipes had sufficient loadbearing strength to be safe under the ground cover and level of traffic. But Dyer & Butler knew of our BD12 HA accreditation and recently used a Tubosider system at the Heathfield In-Vessel Composting site in Devon.
Solution and benefits
The quickly agreed proposal was for a Twinstore system in 1300mm pipe, allowing captured rainwater to permeate into the membrane-lined fill around the tank, and fitting a 5.1 litre/sec flow control unit to keep within the very limited discharge allowed into external drains.
“The whole operation went extremely well, despite all the poor weather, says Alex Gallie, representing a company which through its regional offices carries out a wide range of often complex projects throughout southern England and Wales.
“Having used other lined systems, I was not just pleased that using Twinstore meant we required an excavation area of less than 40 by 18 meters, but that installation was so quick and easy by comparison, with all the preformed sections delivered to match our timings.”