Despite a range of existing soil and water remediation, and waste clean-up, techniques available to nuclear site managers, effective in-situ and ex-situ remediation remain a common technical challenge, particularly at sites with complex or low permeability soils / subsurface geology, and on working sites or sites with considerable surface and subsurface infrastructure. This research builds on emerging sustainable remediation ideas and previous proof-of-concept work at the AWE Aldermaston site to develop novel ex-situ and in-situ low-energy electrokinetic based approaches that can be flexibly applied to different site materials and work around existing site infrastructure, providing new and flexible approaches for complex site materials (including low-permeability soils) at working (and legacy) nuclear sites. Electrokinetic (EK) techniques use a low voltage DC current to control migration of, remove, or degrade contaminants in soils. This project will use electrokinetic test cells containing simulated nuclear site materials at the lab and intermediate-scale (m-scale) to (a) remove, focus or degrade soil-bound contaminants (remediation or waste minimisation), and (b) direct subsurface water, chemical and colloid flow (fencing/containment or forced migration). This PhD project, supporting the PDRA work undertaken within TRANSCEND at Southampton on in-situ and on-site EK system design, and combined EK approaches with colloidal silica grouting, will examine EK application to soils, concretes and other wastes (including EDTA-containing wastes). Specific objectives are: (1) To adapt low-energy ex-situ electrokinetic remediation and waste volume minimisation techniques already proven on AWE legacy wastes (Agnew et al, 2011) to other UK nuclear legacy wastes and site scenarios; (2) To develop in-situ low-energy electrokinetic fencing (for groundwater) and remediation (for soils and sediments), to limit the spread of active contaminants, and minimize soil volumes for subsequent treatment. Simulated pipes, foundations and other subsurface infrastructure will be incorporated into the test designs to simulate on-site conditions, and numerical and physicochemical models of EK and contaminant processes will be developed to inform full-scale on-site application by nuclear site holders.
Academic Lead: Andy Cundy
Researcher: Shaun Hemming
Location: University of Southampton
