The guidance was produced under a research programme run by the British Cement Association and the University of Greenwich called Codes and Standards for Stabilisation and Solidification Technologies (CASSST).
It is intended to be used alongside the Agency's recently published model procedures for the management of land contamination (ENDS Report 357, p 46 ). It provides a structured framework for the selection, design and implementation of solidification and stabilisation technologies.
The guidance defines stabilisation as being the addition of reagents to contaminated materials to produce more chemically stable constituents. Solidification is the addition of reagents to impart physical or dimensional stability and reduce access by air, rainfall and other external agents.
The document primarily examines the use of hydraulic binder systems that are usually designed to provide both leaching and physical improvements to the contaminated material. It notes that there has been relatively poor uptake of these technologies in the UK because of factors including the low cost of landfill, a lack of technical guidance and uncertainty over the durability of the treatments.
Another factor identified as holding back the UK market is past poor practice with cement stabilisation processes in the 1980s and early 1990s.
The guidance recommends the use of bench-scale tests followed by a site trial to assess performance and gain information for the planning of full-scale works. It also describes associated activities to ensure environmental protection and notes that verification procedures are important to increase stakeholders' confidence in remediation schemes.
A separate report in the CASSST programme, reviewing scientific literature in the area, has also been published by the Agency.2