|DECEMBER, 2015, ATLANTA, GEORGIA: A local city council in London, UK acquired a contaminated industrial site for a major residential development to meet the growing housing demands in the area. The site formerly used as a manufactured gas pant (MGP) is contaminated with both LNAPL and DNAPL. The NAPL and its constituents primarily lie within a highly permeable sandy gravel river terrace deposit that is sandwiched between a relatively impermeable upper silty clay unit and the lower London Clay formation. Although previous property owner’s attempted to remediate the groundwater with a conventional pump-and-treat system significant amounts both LNAPL and DNAPL remain persistent within the sandy gravel formation and portions of these plumes have migrated offsite. Prior to approvals for site redevelopment, the city council is required to meet certain LNAPL and DNAPL remedial goals established by the UK Environmental Agency.
A local environmental consulting firm retained EIC to evaluate the optimal NAPL recovery potentials using EICs unique remedial technology known as the non-aqueous phase extraction technique (NET) System. EIC also assisted the consulting firm in designing unique DNAPL recovery wells. During recent field tests, EIC successfully demonstrated the NET system's effectiveness in recovering both LNAPL and DNAPL at a NAPL/total fluids efficiency greater than 99% from both NAPL recovery wells. The UK Environmental Agency also witnessed portions of the recovery potential tests. Based on the subsequent NAPL recovery potential test report the site owner and the consultant are planning to develop a long-term NAPL remediation program using multiple NET System. This approach will ensure that the NAPL is aggressively remediated and enables the site owner to reach remedial end points at a fraction of the lifecycle costs of conventional systems and within a reasonable timeframe.