The site is one of the largest brownfield projects in the UK, measuring 1.5 miles in length.
Upon completion, this site will provide 2,300 low carbon homes, alongside an all-through school, parkland and 12 acres of space set aside for employment space.
Scope of Works
The 89-hectare site is split into numerous phases. Overall, the scope of works includes:
- Demolition of existing structures;
- Removal of concrete slabs and underground obstructions to 1.5m below remediation formation levels;
- Remediation including chemicals and asbestos in soils;
- Extensive earthworks;
- Preparation of 1.5m thick development platforms utilising site-won general fill;
- Management of surface and ground water within the parameters of the discharge permit;
- Creation of a riverside park with biodiversity enhancements.
Remediation
Site investigations indicated the presence of hydrocarbons (Total Petroleum Hydrocarbons, TPH, and Polycyclic Aromatic Hydrocarbons, PAH), chromium and asbestos. These soils are being remediated through hotspot and plume identification, delineation, and treatment of affected soils to allow the site won materials to be reused on site as part of the earthworks process.
Earthworks
Earthworks are being undertaken in two main areas; the former coal yard and the Pulverised Fuel Ash (PFA) lagoons. These two locations are approximately 1 mile apart, so using the existing road network on site, a specific haulage road has been created to enable efficient material movement on articulated trucks, without interfering with remediation operations.
The earthworks include cut and fill to varying degrees across the entire site to achieve the required development phase levels, tying into the existing site access points, and associated existing road infrastructure.
Added Value
We are maximising re-use of site won materials to prepare the site for residential development. This includes processing concrete from the demolished station buildings on site to re-use in the development platform.
One innovation on site is the re-use of Pulverised Fuel Ash (PFA), a product of coal combustion that is usually disposed of as a waste. 550,000 tonnes of unbound PFA was stored on site; this would usually require 30,500 wagon movements to transport the material to the nearest treatment / disposal site over 80km away. Collaboration between all key stakeholders, including regulators, has allowed the careful re-use of all unbound PFA on site through soil mixing techniques and moisture conditioning.
Robust validation criteria have been achieved across the whole development platform. Our solution to treat / re-use the PFA material on site has saved 6.5million tonnes of CO2 emissions and negated significant nuisance to site neighbours.
Habitat Creation
The project includes converting one area of the site from a disused golf course into a green space and riverside park for the future development.
This will create a green corridor and open up a previously inaccessible section of the River Trent for local people to enjoy.
We are creating a series of new ponds, water features and reprofiling a wetland area to create additional habitats, and improve and enhance the biodiversity. We are working with the Client and Staffordshire Wildlife Trust to create these new habitats, with the Environment Agency funding some of these works.