The North Shore area had been historically used as a steel mill as well as dockland. The area had been highlighted as part of a 23-hectare mixed use regeneration scheme which will transform Stockton Riverside (North Shore).
In September 2005, a significant oil / fuel spillage occurred at the location.
Although remediation measures had been taken by the site owners to address the source contamination. It was considered necessary to additionally address dissolved phase contamination. It was considered this could potentially migrate offsite and impact land earmarked for future development and the River Tees.
Envirotreat were commissioned to design a permeable reactive barrier to address the identified dissolved phase contamination arising from the 2005 spillage and to provide the technology / proprietary materials for the barrier installation. Halcrow were engaged as project consultant by the Homes & Communities Agency.
The prime contaminants of concern were identified as total petroleum hydrocarbons (including BTEX) and naphthalene.
Envirotreat proposed and demonstrated that groundwater contamination could be addressed through the installation of a permeable reactive barrier. The barrier was designed and demonstrated as being effective by comprehensive laboratory trialling and modelling techniques. The objective of the barrier was to mitigate the risk of ongoing migration of contaminated groundwater to the identified downstream receptors by severing the pollution linkage pathway.
Following Environment Agency approval the reactive barrier system was installed in April / May 2011. The permeable reactive barrier installation was 330 metres in length and installed to an average depth of 6 metres.