The regeneration of contaminated land by stabilisation/solidification: the findings of a study mission to the USA

Abstract

Stabilisation/solidification (s/s) technology has application in the remediation of contaminated land, particularly brownfield sites that are under pressure for redevelopment. A wide variety of available binder systems facilitate the appropriate treatment of contamination. When hydraulic binders are chosen, the technology typically utilises the high pH and setting characteristics of cements to immobilise and encapsulate contaminants, providing a break in the source–pathway–receptor linkage and minimising contamination of surrounding environments. Whilst commonplace in the USA for the treatment of contaminated sites s/s is currently underused in the UK. The reasons are largely related to regulatory issues surrounding the classification of contaminated land in the UK, historic availability of landfill space, a lack of awareness of the science underpinning s/s and the potential benefits of the technique. This paper describes the results of a study mission to investigate the use of s/s in the USA where it is established as a proven and well-regulated technology. Six sites were visited, including federal Superfund clean-up operations, and the s/s methods and contaminants treated were reported. The authors concluded that s/s is routinely used in the USA as a risk management strategy under a variety of conditions to produce treated products that were fit for their final purpose. Five of the six sites visited were contaminated with organic pollutants, and these were being treated successfully with cement-based binders, despite past concerns that these binder systems may not be suitable.1,2