Asset International Limited (‘Asset’), the world’s leading manufacturer of Weholite large diameter plastic pipes, provided vital sewerage system components to the developers of Sherford, an ambitious environmentally-friendly and modern market town development in South Hams in Devon.
Sherford will have 5,500 homes, four schools and over 80,000m2 of employment and retail space when completed and is located 28 miles to the east of Plymouth, equidistant from Dartmoor and the south Devon coast.
It is the aspiration of the developers that Sherford will be viewed in years to come as one of the West Country’s most admired market towns; one that has the feeling of being centuries in the making, but developed with responsible 21st century practices in mind, including affordable housing and the implementation of renewable energy.
Green practices are very much in the focus for the developers, who claimed that Sherford will be the most green and sustainable new town in the country, conceived with a minimised carbon footprint in mind. All the houses are designed to be energy-efficient, and much of the energy will be provided by two wind turbines on site.
Ecologically friendly good practice has been extended to the procurement processes on site, with many of the suppliers chosen committed to the green agenda, something that Asset place a heavy emphasis on. The company’s green ethos is exemplified by the fact that the production and installation of their signature large diameter plastic pipes has been proven to have a significantly reduced carbon footprint compared with other alternatives on the market, including concrete.
One of the fundamental considerations of any new development is the management of the site’s foul water. Using the standard Sewers for Adoption discharge figure of 4,000 litres per dwelling day for 5,500 dwellings gives a typical discharge rate of 254 litres per second. In order to efficiently manage the vast quantities of foul water flowing through the site once the development is populated, Asset were commissioned to provide a back-up storage tank for Sherford’s foul water pumping station. The vast 3.5 metre diameter 30 metre long, multi-leg Weholite attenuation tank utilises 170 metres of pipes, and holds approximately 1,500m3 of foul water.
The Weholite tank is much larger than its more standard sized counterparts, which usually hold around 200m3, and connects directly to the town’s foul water pumping station. The tank was designed and made to the specific requirements of Fred Champion Groundworks, who were responsible for developing the infrastructure for the site’s sewerage needs.
The tank was designed and supplied with an integral dry weather flow channel to meet the specific requirements set by South West Water. The dry weather flow channel is uniquely designed to improve the hydraulic efficiency of the tank in low flow conditions, helping to avoid silting.
The offline attenuation tank was prefabricated at Asset’s state of the art factory in Newport, and transported to the site in Devon in one piece prior to installation, vastly cutting down on the amount of time spent positioning the tank in situ; a huge bonus to the contractors who are observing stringent timescales.