01932 246 600

GOODLUCK HOPE, LEAMOUTH

11 June 2020

The Challenge

Dealing with a very large mixed residential and commercial use building development in the UK, Cognition had to ensure their remediation strategy was both cost-effective and sustainable. Cognition’s site Investigations identified contaminants of asbestos, hydrocarbons, free product contaminated perched ground waters, and made grounds with high levels of heavy metals on the 25,000m2 site.

 

Our Approach

Cognition agreed a remediation strategy with the appointed environmental consultant  for the site which would provide significant savings to the client. Cognition effectively minimised pile mat installation costs, ensured that minimal materials needed to be disposed off-site, and provided protection to sensitive neighbouring receptors, particularly the River Thames, River Lea, and Trinity Boy Wharf complex. Value engineering ensured that the most cost-effective remediation solutions were used to minimise residual environmental and human health risks. The key elements of these works included;

  • Demolition and site clearance including asbestos removal works;
  • Full Site Investigation (S.I) and provision of a factual report on contamination, hydrology, and geotechnical data;
  • Water treatment to remove free product;
  • Discharging treated waters into the local sewage network under permit;
  • Stabilisation of entire site with cement to form piling mats and reduce surface water infiltration during the construction phase;
  • Stabilisation to encapsulate heavy metal contaminated  soils;
  • Bioremediation of heavily contaminated hydrocarbon impacted soils;
  • Contamination levels were reduced from 9,000mg/kg to <5,000mg/kg and, in most cases, <1000mg/kg;
  • Cut and fill operations under CL:AIRE Materials Management Plan (MMP);
  • Excavation, segregation, and off-site disposal of 33,000m3 surplus soils and other deleterious wastes.

 

Outcome

Cognition successfully completed site Investigations, agreed a cost affective remediation strategy that provided significant reduction in disposal costs for the basement dig (>£4M) when compared with conventional strategies such as dig-and-dump and construction of traditional crushed concrete piling mats on a geotechnically challenging site.