Using Prototyping to Minimise Remediation Costs: a Case Study on a Former Paint Factory

Soils containing high concentrations of metals were treated using a soil washing process. The hypothesis was that metals could be concentrated in a single or small number of fine fractions which could be removed and disposed of to treat the contaminated soil. Lead and zinc were shown to be distributed over the > 4000, 2000–4000, 600–2000, 180–600, 38–180, 38–23, and < 9 µm soil size fractions. The study demonstrated that only one of four of the composites tested, generated a metal-rich fraction as a result of washing and soil fractionation. Using a scaling approach, with a laboratory prototype, this study demonstrates that lead and zinc contamination across the site were not able to be concentrated into any size fraction. Further, the metals could not be concentrated to any commercially viable extent to enable the development of a remediation strategy. The approach illustrated how costs can be contained in developing full-scale remediation processes through using a staged process based on the principles of prototyping and scaling.