Abstract

In-situ chemical oxidation is an established technology for the remediation of contaminated soils and groundwater, with over 20-year history of successful deployment particularly in the US. Conventional oxidants including Fenton’s reagent and ozone, suffer from limitations such as competing reactions with chemical species in the soil and aquifer matrix, which often lead to remedial inefficiencies. Emerging oxidants such as persulphate are being tested and proving to be effective in addressing the limitations of these conventional oxidants. However, very little is known about the interaction of the persulphate with reductive species within the sub-surface. Further, when injected into soils, in-situ chemical oxidation can create unstable ground conditions due to the high water content required to achieve thorough mixing.

This seminar presents laboratory studies on the effectiveness of ferrous-ion activated persulphate in treating diesel range organics-spiked sandy soils under soil-mixing conditions. Further, the potential of treating these soils by cement-activated persulphate was investigated with the aim of establishing post-remedial ground conditions suitable for faster re-use. Using data from different sites across the UK and EU, the research studied the effects of select chemical properties of uncontaminated soil and groundwater on persulphate demand. Finally, lessons learnt from pilot field trials will be discussed.