There is now considerable pressure from central government to develop more brownfield sites. The construction industry must now surely be aware of the much publicised government target that 4.4 million new homes are required by the year 2016 and 60% should be built on brownfield sites. This has firmly placed the onus on the reclamation and recycling of previously used land.
Thankfully there is now a universal understanding in the UK that the once conventional practice of excavating contaminated material and depositing it in a landfill is no longer sustainable, nor is it environmentally or economically acceptable. There is therefore a need for effective and economical insitu remedial technologies for the general treatment of contaminated soils and in particular those contaminated with multiple pollutants.
Various processes are currently being publicised, however they still tend to be contaminant specific, despite claims to the contrary. Most of the popular processes offered by remediation contractors tend to have their limitations. Bioremediation will only deal with organic compounds.
Vacuum extraction in particular has its problems. It deals mainly with volatile organics compounds which again leaves inorganic contaminants in the ground. It also requires the contaminant plume to be accurately defined and contaminant concentrations may continue to rise after remediation is supposedly completed, even if the source of the pollutant has been removed, due to enforced draw-through effects.
At May Gurney we have developed an insitu solidification/ stabilisation process. This chemically fixes and encapsulates soil and so can be used as a simultaneous treatment and ground improvement technique. The system can be used to control the migration of polluted groundwater through a 'reactive gate' to remove soluble pollutants, providing one of the most comprehensive remediation solutions available.
Dr Chris Evans, project engineer, May Gurney (Technical Services)