Case studies

Bioremediation

Case studies

Hereford - Bioremediation of a former army base


George Wimpey Strategic Land commissioned RemedX to investigate a 20-hectare former military site in Hereford. To provide an early indication of areas of concern across the whole site, a preliminary ground investigation and a qualitative risk assessment were conducted. A subsequent series of detailed ground investigations were then targeted on the identified areas of concern to inform quantitative risk assessments.

The risk assessments showed that remediation was required in a hydrocarbon-impacted area, located within the critical initial phase of the housing redevelopment. Contaminated soils were excavated from this area and replaced with clean crushed material arising from demolition works compacted in layers, allowing the housing development to commence without delay. The contaminated soils were moved to a large area of hardstanding located within a later phase of the development, the demolition of which was postponed allowing its use for this purpose. The treatment of the contaminated soils by bioremediation continued as building was progressing in the infilled area, without any impact on the construction programme. Treated soils were subsequently reused to raise levels within a public open space area, as drainage considerations required a general increase in levels across the site.

Conclusions:

  • The phased investigation allowed rapid assessment of potential areas of concern
  • The ex-situ remediation strategy allowed the housing development to commence without delay in the area that had been impacted, while remediation continued in another part of the site
  • The remedial strategy can be applied to other sites with similar contamination issues.

 

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