Remedial Strategy Statements
Remedial Strategy Statements are produced either following the completion on the Phase 2 site investigations works and generic risk assessment or following completion of the DQRA. They clearly set out how any remedial works are to take place (e.g. type of remediation to take place, the area which will be remediated, where will the contaminated spoil go to etc), and to what clean-up criteria the site is to be remediated to.
The extent of any remedial works undertaken depends upon the nature and concentrations of the contamination involved, the nature and location of the identified receptor(s) and the presence of potential pollutant pathways.
In general remediation is carried out to manage significant environmental (e.g. to aquifers, watercourses) or other risks (e.g. to human health) posed by contaminants in the ground (including groundwater). Remedial options fall into the following categories:
- Excavation and removal of materials off-site primarily to landfill. Until recently this has been a major means of site remediation in the UK. However, recent controls on waste acceptance by landfill mean that landfill availability has been greatly reduced, and both gate fee and transportation costs are increasing.
- Containment based approaches are designed to prevent or limit the migration of contaminants left in place or confined to a specific storage area, into the wider environment. Approaches include the use of barriers that are impermeable to water or gases, and hydraulic measures based on the removal of fluids before they are able to spread into the wider environment.
- Treatment based approaches destroy, remove or detoxify the contaminants contained in the polluted material (e.g. oil, groundwater).
The remediation of a residential site could be as simple as installing a protective capping layer in garden areas to prevent end users from coming into contact with ashy Made Ground soils which contain elevated concentrations of arsenic (say). Alternatively, remediation of some organic contaminants within groundwater can be difficult to achieve and take many years to complete.
There are many remediation technologies available and on difficult sites remediation contractors should be involved at an early stage so that the most effective and cost effective remedial solution can be determined and agreed with the regulators prior to any remedial works proceeding.
Following completion of the remedial works a validation report is produced which documents all of the actual remedial works which were undertaken on the site to clean the site up to the regulator (Local Authority and/or Environment Agency) approved remedial clean-up target concentrations which were set out in the Remedial Strategy.
Please review some of our recently completed projects in the case studies section.
All works must be approved by the Local Authority and Environment Agency (if controlled waters are involved) prior to any contaminated land planning conditions being discharged.
All contaminated land related works are undertaken in accordance with:Government published Contaminated Land Regulation guidance (especially CLR11) Planning Policy Statement 23 BS10175:2011 + A1: 2013 'Investigation of potentially contaminated sites – Code of Practice' BS5930:2015 'Code of practice for site investigations' CIRIA C665 'Assessing risks posed by hazardous ground gases to buildings' NHBC Standards Plus 2017 Chapter 4.1 'Land quality – managing ground conditions'.