CEEQUAL Excellent (85.7%) – Whole Team Award
Version 4, January 2018 | Chesterfield, England
|Winner – CEEQUAL Outstanding Achievement Awards 2019 – Restoration of Contaminated Land|
The former Avenue Coking Works at Wingerworth near Chesterfield was one of the most contaminated sites in Europe. The plant opened in 1956 and produced smokeless solid fuel through the carbonisation of coal. In addition, the plant processed by-products such as benzole, tar and sulphuric acid. It also produced town gas, for domestic use in Chesterfield, and generated electricity for its own use and the national grid. Following its closure in 1992, the works lay disused until East Midlands Development Agency (emda) commenced remediation of the 98 ha site, the size of around 140 football pitches, in 1999.
The facility included a waste tip and settlement lagoons for the disposal of solid and liquid wastes. Disposal was based on the ‘attenuate and disperse’ principle, which was an accepted technique at the time. Contamination from the site, particularly the waste tip and lagoons, is known to have polluted the River Rother that runs through the north of the site. The former plant also contaminated the underlying soils through leaks and spills from the numerous tanks, pipelines and sumps. The use of the site led to significant contamination, including with hydrocarbons, asbestos, cyanide and metals.
Following the inclusion of the site in Tranche 1 of the National Coalfields Programme in 1996, it became North East Derbyshire District Council’s highest strategic priority for both regeneration and housing growth. Homes England, North East Derbyshire District Council and Derbyshire County Council worked together with key partners, Jacobs, Turner and Townsend and VSD Avenue, to achieve the ambition of the site becoming a new place to live and to enjoy.
The restored landscape provides a development platform for 489 new homes, a primary school, community facility and employment, along with a further 70 Ha of public open space incorporating a Sustainable Drainage System, high quality sports pitches, multi-user trails connecting to local cycle networks, woodland, car parking, reed bed, ecological habitats and a flood alleviation dam to provide protection to downstream properties.
There was no process of ‘optimising’ the location of this project, it being fixed by the location of coking plant. As such, the environmental context was given and had to be carefully managed to avoid worsening the environmental issues present. As well as the immediate impacts on and future potential risks to the River Rother, another key consideration was the management of the sensitive ecological features that had become established. The former was managed by an extensive site investigation and risk assessment process, followed by development and implementation of a carefully-designed, comprehensive remediation strategy. The latter was managed by pre-construction ecological enhancement and creation works, along with careful management and monitoring during the remediation activities.
Another key consideration was the sensitivity of the site in terms of the perceptions and expectations of the local community. Significant efforts were made to ascertain the wishes of the local community for the finished site through a comprehensive pre-masterplan public consultation exercise. The community was kept appraised of progress during the works via a number of forums and any concerns were immediately addressed.
Benefits of using CEEQUAL
The main driver for undertaking the CEEQUAL assessment was the client’s commitment from the outset that the project should be undertaken in as sustainable a manner as possible. As well as many of the principles of the CEEQUAL scheme being incorporated into how the project was set up and implemented, the independent verification of the assessment meant that the client could objectively demonstrate to stakeholders delivery on the early commitments made.
Which elements of the project highlighted best practice and innovation?
- Ecological assessment, design and management.
- Comprehensive investigation and detailed assessment of the site; careful design of the remediation strategy, including reuse of materials based on risk assessment, and significant consequential savings in materials and energy/carbon.
- Effective stakeholder consultation.
The transformation of the site from its heavy industrial heritage to a thriving residential and public open space amenity is testament to the vision of Homes England and the contribution and support of all stakeholders during the construction phase of the scheme. VSD are delighted to have played a part as the contractor in delivering and overcoming the challenges faced in the execution of such a complex remediation and regeneration project
Jim McNeilly, VSD chairman of the Joint Venture Board (Contractors)
CEEQUAL Section Specific Achievements
Sustainability has been at the heart of this project since its inception. The client’s vision was for the site to be returned to beneficial use from its state of industrial dereliction, for the benefit of the environment and the local community.
When operations ceased in 1992, the plant was effectively just ‘switched off’ and left derelict. As a result, when emda took ownership in 1999, there were significant immediate health, safety and environmental issues to address. These included the presence of hazardous substances (tars, acids, etc.) in pipes, tanks and other structures which were in danger of collapse, and liquid and solid hazardous wastes in tips and lagoons. One of the lagoons was thought to be in danger of collapse into the River Rother.
An environmental management system (EMS) was developed which provided a systematic means of assessing, prioritising and managing these risks. This was certified to ISO14001 and later registered under the EU Eco-Management and Audit Scheme (EMAS), thought to be one of the first project-based systems to be registered under the scheme.
Numerous site investigations, surveys, assessments and trials were undertaken, which provided an in-depth analysis of the nature and extent of the contamination. Using the outcomes of this, a remediation strategy was developed. This information was further enhanced through a full environmental impact assessment (EIA) of the proposed development. Full planning permission was obtained in 2007.
The remediation strategy focused on reclaiming as much of the contaminated material as possible, resulting in as little as possible being disposed of. The strategy comprised the remediation of contaminated materials using techniques such as ex-situ bioremediation, screening and soil washing, as well as thermal desorption.
The environmental masterplan included detailed monitoring of air quality, water and ecological and biodiversity impacts.
People and Communities
Since the construction of the coking works in the early 1950s, through its operation until 1992, and during the remediation and landscape project, the general public was excluded from most of the site. However, given the high profile of the remediation project and the site itself, the client was very proactive in engaging with the local community, regulators and other stakeholders right from the beginning.
The outline masterplan was rolled out via a series of public consultation roadshows, at which views were invited on what the local community wanted the site to look like and for what it would be used when completed. Where appropriate, these ideas were incorporated into the masterplan design. This consultation effort extended into the construction phase, with a number of forums set up to allow effective communication between all parties; this included the implementation of a community odour diary programme to encourage active stakeholder involvement in the project and provide vital additional operational information to the project team.
This programme has taken nearly two decades of meticulous planning and execution with Homes England and partners to restore one of the UK’s most complex remediation sites into an area that can be enjoyed by the community for years to come. The scale of the change at the site continues to amaze people when they visit and we take significant pride in sharing the history of the project and the technical innovations which have brought it to this stage.
Donald Morrison, Jacobs’ Buildings and Infrastructure Europe Senior Vice President and General Manager
Land Use and Landscape
The coking works represented a completely unnatural feature in the landscape; as well as the presence of a large number of industrial buildings, the landform itself was altered to allow the works to be constructed and operated, with the natural, gently sloping valley replaced by a series of engineered terraces. The masterplan involved the removal of these harsh features and the restoration of a landform that is more representative of the surrounding rolling, semi-rural landscape.
The project has involved the creation of approximately 70 Ha of public open space, comprising the realignment and restoration of the River Rother to a cleaner and more ‘natural’ state, high quality sports pitches, multi-user trails connecting to local footpath and cycle networks, and new areas of woodland. The eventual construction of 489 residential dwellings will complete the transformation of the site to being truly beneficial to the local community.
The Historic Environment
The site sits within the immediate context of the historic Wingerworth Estate, which was home to the Hunloke family for over three hundred years. A broad avenue of two parallel lines of trees historically ran east from the Hall, which was demolished in the 1920s, down to the River Rother and beyond, giving the site its name.
Although the avenue no longer exists, this local historic feature is reinterpreted within the proposed development to provide a link to the historic landscape, creating strong east-west connections through the Avenue area connecting existing villages and the new development to the new parkland created along the River Rother, and to provide a key place-making feature within the development. This was an opportunity to finally, within a 21st century context, complete a landscape that is every bit as exciting and visionary as the one imagined two centuries ago, and in the process to transform the site into a beautiful place in which to live and work.
Ecology and Biodiversity
Following the closure of the coking plant the site was colonised by a number of protected species, such as great crested newts, water voles, kingfishers, grass snakes and badgers, and others of interest, including lapwings. Extensive surveys and exclusion works were carried out to allow enabling works and remediation activities to take place. Advance habitat creation works were undertaken to provide suitable alternative areas for water voles and translocation of some 8,000 newts and other species to allow the works to go ahead. Amongst other benefits, this provided the necessary conditions for the development of a nationally important population of great crested newts.
The completed project includes significant new areas of wildlife habitat, primarily associated with the remediated River Rother.
The Water Environment
The derelict site presented a significant risk to the surface and ground water environment, in terms of continuing pollution from waste lagoons to the adjacent River Rother and underlying groundwater. The project involved breaking the source-pathway connection by removing and treating contaminated materials and moving other potentially high risk materials away from sensitive receptors. During remediation activities, a water management plan was implemented that ensured separation and appropriate management of clean and dirty/contaminated water. Contaminated water was treated on site for disposal to sewer; clean water was used where possible for purposes such as dust suppression.
The completed project includes a remediated river that follows a more natural, sinuous course through the north of the site. In addition, the completed project includes a surface water feature which attenuates flows from the site to the River Rother.
Physical Resources – Use and Management (Energy, Water, Materials, Waste)
The client’s commitment to sustainability led to the development of a restoration solution which aligns with the principles of the waste hierarchy. Practically, this meant the re-use on site of all materials that could technically be treated. The landform was designed to incorporate all the treated materials, with minimum requirements to import new or reclaimed materials.
The careful planning for the reuse and placement of materials, involving the development and implementation of bespoke reuse criteria, meant that a significant quantity of material was suitable to be reused (in low risk areas) without treatment, resulting in significant savings in terms of energy use/carbon emissions and chemical/resource use.
Due to the cocktail of different chemicals present at the Avenue, no single remediation treatment was found to be fully effective in removing the contamination. The contaminants of concern identified comprised: PAHs (poly-aromatic hydrocarbons), phenols, DROs (diesel range organics), PROs (petrol range organics), BTEX (benzene, toluene, ethylene, xylene), cyanide, thiocyanate, ammonia, heavy metals (arsenic, nickel, cadmium, chromium), asbestos.
The remediation strategy therefore comprised a number of different techniques which, when combined, rendered the materials safe for re-use. These included:
- Thermal desorption
- Ex-situ bioremediation
- Enhanced separation and screening
- Concrete crushing and grading.
Apart from relatively small volumes of hazardous substances such as asbestos and tar that were sent for off-site disposal, the vast majority of material, following clean up, was re-used in appropriate locations across the site.
Due to previous uses of the site, only a small amount of topsoil remained. A key part of the remediation works involved the manufacture of more of this precious resource using site-won as well as imported, locally-sourced compost. All vegetation that was cleared as part of the enabling works was retained on site for use for this purpose.
Significant transport savings were achieved through the implementation of the remediation strategy, which avoided the requirement to transport significant volumes of waste from and materials to the site.