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Brownfield regeneration remains key to the Government’s plan for creating sustainable communities, with as much as a third of the 66,000 ha of brownfield land identified by the National Land Use Database readily available for development in England. However, crucial to brownfield regeneration are the issues of restoring the land to a high quality as quickly and cost effectively as possible, especially if it is contaminated.
WRAP (Waste & Resources Action Programme) has been working with industry partners to investigate methods for both creating and improving the quality of topsoils, which are both cost effective and sustainable.
Historically, developers looking to source good quality topsoil have chosen to import it, disposing of the site’s original subsoils and other mineral resources to landfill, which can result in significant financial and environmental costs.
One alternative being investigated is the manufacture of topsoil in-situ by mixing organic materials with existing subsoils. For example, high quality PAS100 compost produced from municipal garden waste (such as grass cuttings, pruning and leaves) is a recycled product that can be used to manufacture a soil capable of supporting healthy plant growth.
Furthermore, the benefits of using quality compost don’t just stop once the initial soil development has been completed - compost contains slow-release nutrients such as nitrogen and phosphorus which can help offset any future need for inorganic fertilisers.
WRAP is undertaking a series of trailblazer projects across the UK, to investigate and demonstrate the financial and environmental benefits to developers, designers and contractors of specifying and using locally sourced quality compost in brownfield projects.
Paul Mathers , Key Account Manager for Brownfields at WRAP, said: “Previous trials conducted in conjunction with WRAP have revealed that using PAS 100 compost not only helps create a soil with improved nutrient content, moisture retention and plant growth potential, it can also help significantly improve the project’s bottom line. In some cases, costs have been reduced by more than 50 per cent.”
Please see below details of two of the trailblazer projects:
Lumley North and Coxhoe East
The former landfill sites, at Lumley North and Coxhoe East, are being regenerated for biofuel production. The 60 hectare sites have used up to 1,000 tonnes of BSI PAS 100:2005 compost per hectare to improve the poor quality topsoil, which has been planted with short rotation coppice willow.
The fast growing willow will be harvested and used as biomass – a sustainable fuel resource that will provide energy for the local area. Assessment of the establishment and yield from the willow grown in compost will be compared to the same crop under conventional agricultural conditions grown in the same region. This will determine whether low-value sites, such as former landfills, can generate cost effective biofuels using organic materials.
Former Royal Ordnance Munitions Factory, Chorley
The former Royal Ordnance Munitions factory in Chorley is in its second phase of redevelopment. Over 250ha of land is being remediated at the site, which will be developed to accommodate a mixture of light industry and residential housing. Large areas of soft landscaping and public open spaces are also planned.
26,000 tonnes of topsoil is being manufactured on the site using a mixture of BSI PAS100:2005 compost and sandy clay loam subsoil, enabling the establishment of wildflower meadows, amenity grassland and woodland habitats.
To find out more about how PAS 100 compost can help reduce the cost of brownfield regeneration projects, contact WRAP on 0800 100 2040, or visit www.wrap.org.uk/composting.