Dealing with one of the largest mixed residential and commercial use building developments in the UK, Cognition had to ensure that their remediation strategy was both cost-effective and sustainable.

Extensive Site Investigations identified contaminants of asbestos, hydrocarbons, free product contaminated perched ground waters, and made grounds with high levels of heavy metals on the 40-acre site. Cognition met with the Local Authority and Environment Agency and agreed a remediation strategy for the site that would target the sources of contamination, protect the wider environment and human health whilst providing significant savings to the client.

Key achievements of the project include:

• Successful demolition of buildings and underground structures.
• Removal and treatment of free product using a water treatment plant.
• Bioremediation of >320,000m3 of hydrocarbon contaminated soil, reducing TPH from 75,000mg/kg to < 10,000mg/kg and, in most cases, below 1000mg/kg.
• Protection of sensitive neighbouring receptors (particularly the River Thames) using cutoff walls and permeable reactive barriers.
• Stabilisation of entire site with cement to form piling mats and reduce surface water infiltration during the construction phase and stabilisation to encapsulate heavy metals.
• The works were completed over five phases and delivered significant savings to the client in excess of £100M, when compared with conventional strategies such as dig-and-dump, extensive water treatment and construction of conventional crushed concrete piling mats.

To find out more about Cognition’s expert works on this project, please visit the following link: https://www.cognitionlandandwater.com/case-studies/Royal-Wharf-Silvertown/