Soil Manufacturing for Land Restoration Project
Summary
A major land reclamation and restoration project was undertaken at the former Lambton Cokeworks in County Durham. A significant challenge in the restoration of this contaminated land site, was to create soil conditions that supported a wood and grass land habitat. The only viable solution was to design and manufacture soil on site. Soil Environment Services were commissioned to identify materials and a soil manufacturing process that would be economically, environmentally and socially acceptable. The materials used in the manufacture of soils on-site were successfully developed through field laboratory and larger scale trials.
As part of a major land restoration project at the former Lambton Cokeworks in County Durham, Soil Environment Services was commissioned to provide expert advice on the design and manufacture of soils.
The 60 hectare brownfield site had been earmarked for redevelopment for housing and an area of landscaped wood and grassland. In order to support the development the natural habitat the site needed to increase the volume and quality of on-site soil. Bringing soil onto the site was not economically or environmentally viable. A soil manufacturing solution needed to be developed but this meant overcoming several challenges.
As this was a contaminated land site, the manufacture of soils faced some challenges in identifying organic and mineral materials on-site that met the Contaminated Land Regulations 2000.
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On-site pot trials of different soil blends
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Furthermore, there were site-specific logistical and resource issues that needed to be considered in the specification, design and manufacture of soil on the brownfield site. This included soil design that was compatible with available machinery and limited the amount of material that needed to be brought onto the site.
Larger scale soil trials |
An initial survey identified material on-site that could potentially contribute to the soil manufacturing process.
It was inevitable however that some material would need to be sourced off site so a review of available material that could economically contribute to the production of soil was undertaken. Paper mill crumb, which is a waste product of paper production, was found to have qualities that could contribute to soil manufacturing.
From the site itself, clay, crushed concrete and colliery shale were also identified as potential materials for the development of soil for the site.
From this initial review and analysis, a field laboratory was set up to run small scale trials of a number of soil mixes. Plastic tubs containing various soil mixes were propagated with grass seed and growth was monitored.
Larger scale trials were then undertaken for six soil profile designs. These tested the soils for tree and grass growth and the ability of machinery to handle each soil design.
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From these trials a soil profile and soil manufacturing process was designed and implemented. The soil will be applied to both woodland and grassland areas on the site and utilise 25 000 tonnes of green waste and 80 000 tonnes of paper mill crumb.
The project was one of the highest performing projects under the WRAP (Waste & Resources Action Programme) trailblazer initiative.
There is an increasing demand for soil design and manufacturing in land restoration and reclamation projects. Often faced with issues of contaminated land, resident pressure to keep limit site traffic and the high cost of importing soil, then soil manufacture provides an effective financial, social and environmental solution. |
Completed landscape supporting habitat growth
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