Environmental Assessment

Remediation method statement

The interpretative report detailing the site investigation and associated risk assessments will, where necessary, include recommendations for remedial actions. These recommendations will be reviewed by the regulators involved in the project, which will typically include the Environment Agency, the local planning authority and any warrantors for the scheme.

When the requirements for any further work or amendments to the recommendations have been agreed, it is routine to formalise the remedial process in a remediation method statement (RMS). This document details the measures required to make the site suitable for its proposed end use, including any monitoring and validation works. The RMS will list the documents required to be collated such that at the end of the process there is sufficient evidence to discharge the relevant planning conditions.

The RMS can be used to convey the particular requirements to third parties like ground workers, to ensure that all parties are working to the same specification. The RMS is issued to the regulatory authorities to obtain their written approval prior to commencement of any remedial works.

Depending on a number of factors like ground conditions, the physical or chemical characteristics of the contaminants and the development proposals; a range of remedial options available to developers include the following:

  • Bunding and capping
  • In-ground barriers
  • Stabilisation and solidification
  • Soil washing and air sparging
  • Pumping and treatment of contaminated water
  • Vacuum extraction of vapours
  • Bio-remediation (in-situ and ex-situ)
  • Excavation and replacement (‘dig and dump’)
  • Segregation and screening of materials
  • Methods of ground gas ingress prevention

Historically ‘dig and dump’ was the typical remediation strategy employed to remove contaminated soils off site. However, given the unsustainable nature of this approach and the costs for disposal to landfill, this method is typically seen as the final resort. The export of site soils and import of replacement soils have both cost and environmental impacts. It is preferable and more cost effective to develop a strategy which minimises export and import of soils, and maximises re-use of site-won materials.

Historically ‘dig and dump’ was the typical remediation strategy employed to remove contaminated soils off site. However, given the unsustainable nature of this approach and the considerable increase in costs of disposal to landfill in recent years, this approach is more typically seen as the final resort once all other options have been explored. The export of site soils and associated import of replacement soils have both cost and environmental impacts, and it is preferable and typically more cost effective to develop a strategy which minimises export and import of soils, and maximises re-use of site-won materials.

Over the years RSA Geotechnics have been involved in numerous projects involving alternative remedial treatments and processes, giving us the knowledge and experience to recommend a range of remedial options to our Clients as appropriate, to minimise disposal to landfill and maximise sustainability.

It is important to consult with the planners and regulators from an early stage in the design. The regulatory authorities should be informed of progress throughout the investigation and monitoring phase. This degree of early involvement is often instrumental in obtaining the agreement of the regulators for the remedial strategy during the design stage and also helps to streamline the validation process.