Earthbanks - Proof-of-Concept Research and Demonstration of Soil Storage and Reuse, Depots, and Soil Treatment / Fabrication Facilities 

In  2022, soils comprised 58% of landfill waste (by volume) (Defra Environmental Improvement Plan, 2023). This is not sustainable and demonstrates poor stewardship of soil and natural resources. Acknowledging this Defra is committed to i) publishing a revised Code of Practice for the sustainable use of soil on construction sites, which will help to reduce the amount of soil sent to landfill, and ii) beginning development of a soil storage and reuse depot scheme to help prevent soil that would otherwise be classified as waste going to landfill, and encourage remediation and reuse of soil; and will start piloting this by 2026. 

To support these aspirations the Earthbanks initiative will lay important groundwork to scope blockers to the operation of high-quality soil storage and reuse depots, soil treatment centres and soil fabrication facilities, and will identify practicable measures to remove these blockers. 

The lack of local reuse sites or misaligned development phases is often the biggest blocker to soil reuse. Providing a repository / space to hold and maintain soil significantly increases the probability of finding a reuse site and avoids valuable soil resources being disposed of at landfill. 

Some Soil Treatment Facilities (STFs) currently operate in England & Wales. Few operate using the CL:AIRE Definition of Waste: Code of Practice (DoW CoP) e.g., to release soil back to the market. Typically, such sites provide a feedstock for large recovery or disposal operations (e.g. for use as daily cover at a disposal site). As such they are considered less sustainable. Current customers of existing facilities should be interested in an improved system, especially where this provides a higher quality product, and a more transparent and efficient system. 

An Earthbanks soil depot system would involve high quality facilities for the testing and management of excess soil and ground forming materials including but not limited to: 

• advanced digital material tracking systems, 
• a comprehensive testing laboratory, and 
• a range of management services for soil.  

These 'Earthbanks' would play a key role in promoting the sustainable management and reuse of soil in the construction industry, while also protecting the environment and public health. They would allow for further research and demonstration of the sustainability gains of high-quality soil management and manufacture. 

Soil depots, as outlined in the Defra Environment Improvement Plan 2023 and under the expected Defra Sustainable Soils Strategy (previously referred to as SHAPE) and associated guidance, will be sites where valued material is “banked”, stored, and protected to enable onward use at third party sites. Such uses could include: 

• landscaping soils, 
• engineering fill, 
• clay materials for lining/capping/flood defence works, and 
• inputs into manufactured topsoil and subsoil when certainty of use arises. 

This onward use can already be controlled by the CL:AIRE DoW CoP system. Such Earthbanks would be most beneficial where they can be located at multimodal hub locations. Some could make use of mineral extraction sites requiring restoration or habitat creation schemes. 

The Earthbanks initiative 

The goal of the Earthbanks initiative is to demonstrate how a network of soil depots could be created that can: 

• accept soil from construction and development projects, 
• offer long-term storage, 
• redistribute soil to other construction sites in need of soil using the DoW CoP. 

Beyond this simple modus operandi, there is further opportunity for the Earthbanks initiative to demonstrate how such a network could further the sustainable reuse of soils by exemplifying approaches to soil treatment and the fabrication of bespoke soils to meet specific geotechnical or habitat sustaining objectives. Thus a further goal of the Earthbanks initiative is to demonstrate how a network of soil depots could be created that can also align to Soil Treatment Centres and Soil Fabrication Facilities 

To move the concept of Earthbanks outlined above toward reality, proof-of-concept demonstration projects are required. CL:AIRE and partners are pleased to propose a new phase of practical demonstration to develop soil reuse depots.  

The initiative aims  to develop a framework and guidelines for the establishment of soil depots or Geo-Resource Hubs (Earthbanks) across England and Wales. These depots would serve as central facilities for the testing, management, and reuse of excess soil from construction and development projects. Learning from this proposed practical research will help codify a more detailed system into the DoW CoP ready for widespread industry use. Coordination of this approach through the DoW CoP, with additional controls, ensures this will become a good-practice, joint industry, government, regulator approach . 

The initiative has four major objectives – 

1. Exemplify a minimum of 3 demonstration transfers of material(s)

• one transfer of clean, naturally occurring material, 
• one transfer of contaminant-impacted materials (requiring treatment), 
• one transfer of fabricated soil (requiring production).  

2. Use and improve currently available methods

• be small scale initially (<1,000m3 / scenario), 
• adopt the DoW CoP, and 
• use Regulatory Position Statement 215 enabling material reuse without environmental permits. 

3. Provide valuable outputs

• create a detailed set of procedures for operating Earthbanks, 
• conduct a life cycle and carbon assessment of this form of soil management vs traditional approaches, 
• conduct a cost benefit analysis of such facilities / depots, 
• scoping for fabricated soils to facilitate specific habitat creation as aligned to biodiversity net gain objectives.  

4. Focus on skills & technology

• assess the necessary skills and training for personnel operating Earthbanks, and 
• review and potentially select and adopt digital tracking options to control the material transfers, 
• development of an Earthbanks App to support engagement in soil reuse via a tactile user experience platform.  

The initiative aims to engage with relevant regulatory authorities and policymakers to advocate for the development of policies that incentivise soil reuse and discourage soil disposal. It will achieve this by developing clear guidelines and standards regarding soil depot management including testing, quality assessment, and remediation techniques which can be relied on to support such policies. The initiative will ensure that the regulatory framework aligns with the goals of sustainable soil management, making it easier for construction and development projects to adopt soil reuse practices and contributing to a circular economy. 

The end goal is to encourage the creation of a network of Earthbanks across the country to promote the sustainable management and reuse of soil in the construction industry while protecting the environment and public health. The initiative aims to contribute to a sustainable future by promoting the reuse of soil resources, reducing reliance on landfill sites, and fostering a circular economy model. 

• Tracking 

Digital tracking systems will be a critical part of this process to ensure the accurate management and tracking of soil materials. 

Appropriate digital materials tracking systems will: 

• enable the efficient and accurate tracking of soil from construction sites to soil reuse depots and on to other construction sites, 
• ensure that soil is responsibly managed and tracked throughout the entire process, 
• create the confidence needed in the process to gain government and regulatory support, and 
• ensure local neighbourhoods and the general public have confidence in the safety of such sites. 

Tracking systems must also link to eventual long-term monitoring of reused soil. 

This research will review the current soil / waste management industry and identify challenges and opportunities. There are several suitable tracking systems already on the market for these activities, both for transfers and for on-site materials tracking between stockpile and treatment activity. These tracking systems can be developed further specifically for application on materials passing through a facility / depot. 

• Soil Declaration Passports 

This initiative will develop the current DoW CoP Declaration system to ensure it performs the required dual purpose of 

• creating an audit trail of projects using the scheme, and 
• acting as an initial point of detail for the material, confirming key information such as its site of derivation. 

The initiative will assess the best way of assigning a soil passport documentation system to soil batches being transferred. 

• Skills & Education 

The Earthbanks initiative will: 

• analyse the skills required to operate and manage such a system, 
• assess and create a necessary curriculum on soil science and soil health soil management and reuse,   
• develop a training programme(s) and provisions, 
• ensure all personnel involved in the operation of the soil reuse depots are trained and qualified to manage the process (including the materials tracking system). 

This initiative will promote sustainable development in the construction industry and will create new employment opportunities and promote skills development in this field. 

Investing in the skills and training required to operate and manage such depots / facilities, will increase the likelihood of the long-term success of the initiative and that it will make a meaningful contribution to the development of a sustainable and skilled workforce in England & Wales. 

• Quality Assurance & Testing 

High quality outputs from soil depots are essential. This is crucial to gaining regulator approval for the future, wider use of such depots and facilities. Therefore Quality Assurance systems must ensure this outcome.  

At a soil reuse depot, several on-site soil testing methods would be employed to assess soil health, soil quality and to identify any emerging contaminants alongside those which are commonly found (in addition to use of MCERT accredited labs for common testing suites). 

The most useful on-site soil testing methods will depend on the specific types of soil being received at the depot and the potential contamination related to the Donor site’s previous uses.  

Alongside the common analysis already used in industry, this initiative will build on the outputs of the ReCon Soil project which focused on soil testing technologies. 

Soil reuse depots / facilities will be useful locations for the assessment and remediation of emerging contaminants such as microplastics and PFAS. They will provide a location where soil can be brought for testing and management, using specialised techniques. This might include screening tests for the presence of microplastics and PFAS, for example. 

Soil testing will especially extend to Receiver sites, at which soils will be reused. The long-term performance of these materials must be monitored and understood. This information can then be fed back to the facility for further improvements to the processes. 

• Long-term Storage 

The goal of any storage depot should be to minimise the time in which soil is held. However, when it takes longer to find a reuse for material it is important to understand the impacts of this on the material and the depot site. 

As such this initiative will also assess: 

• the impact of stockpiling on soil health (building on the work of  ReCon Soil), 
• testing and monitoring of soil health whilst stockpiled, 
• tracking of soil in a storage site, 
• contractual issues, 
• understanding reasonable time limits, 
• the development of DoW CoP reuse values e.g. safe and appropriate values for storage / leachate / runoff / health of workers / potential end use, 
• improving the market for finding soil reuse options e.g. tools such as the CL:AIRE Register of Materials. 

Team 

The Earthbanks Initiative is backed by a core team of UK-based partners who successfully delivered upon of the EU Interreg funded ReCon Soil project (URL). In addition, it seeks to attract organisations able to play a practical role in the work e.g., facility operators, consultants, contractors, and site owners / developers. The initiative is building a network of experienced construction professionals. These will collaborate with the core team of the Earthbanks initiative. 

The initiative benefits from extensive experience in environmental and sustainable development projects, and has the highest levels of expertise, skills, and resources to successfully deliver this work. The team wants to work closely with your organisation and government bodies to ensure the success of this initiative and to make a meaningful and practical contribution to a sustainable future of soil.