Carbon Reduction Design Tool (CReDiT) for excavation and clean cover remediation

Meeting the 2050 net-zero carbon emission target requires all sectors of civil engineering to include the reduction of greenhouse gas emissions (‘carbon emissions’) in their designs. This paper presents the development and early achievements of the Carbon Reduction Design Tool (CReDiT) for excavation and clean cover remediation of brownfield sites. The tool was developed for this remediation technique, as it is the dominant remediation method used on residential redevelopment sites within the UK. CReDiT determines carbon emissions from the complex processes involved in this form of remediation – for example, excavation of soil, use of raw materials, transport of materials, waste and recycling and reuse of materials. The application of the tool, to evaluate carbon emissions from excavation and cover remediation options applied to a former landfill site, is presented. In this case study, CReDiT quantifies carbon emissions and material volumes for proposed design options. It also demonstrates the carbon savings that can be made by the effective reuse of material on-site and the contribution of waste materials to carbon emissions. Additional carbon savings through the reuse or recycling of carbon rich or valuable materials are also calculated. The use of CReDiT has led to a rethink of remediation excavation and cover design. Excavated/waste materials are re-evaluated as a resource, material reuse options are assessed and carbon reduction is included in the design process. This leads to more sustainable remediation solutions.