Historic leakages at an active manufacturing facility in Northern Italy resulted in the underlying groundwater becoming impacted with hexavalent chromium (Cr(VI)) contamination of up to 2,000 μg/L, and chlorinated solvents (CHC) concentrations of up to 10,000 μg/L. 3-D Microemulsion® (3DMe) and Metals Remediation Compound (MRC®) were selected to remediate the site because of:

  • The combination of products allow for effective distribution and treatment within a highly heterogeneous and deep aquifer comprising gravels and boulders;
  • Minimal disturbance caused by in situ remediation activities and the ability to inject indoors, on this tight and busy site.

Design and Application

The site was split into a number of zones, which have been treated in phases. For the source zone, 3DMe and MRC were injected into 16 wells on a 3m x 3m grid, providing a targeted treatment of the most impacted part of the site at a depth of 5 to 9 mBGL.

The plume was then addressed through the use of a 3DMe and MRC barrier, which stopped the migration of the contaminant plume offsite, without affecting the groundwater ow itself. The application was completed through 8 xed, multi-level wells installed from 5 to 25mBGL. Since this injection, further areas of the site have become accessible and future applications are planned.

What’s Special?

  • MRC provides rapid and sustained immobilisation of Cr(VI) by reducing the soluble hexavalent chromium into solid, non-hazardous trivalent chromium, which settles out of the groundwater.
  • 3DMe’s unique self-distribution mechanism allowed effective wide area treatment of both CHC’s and Cr(VI) with limited access onsite.
  • The remedial works included treatment inside an historic building
  • Remediation works were carried out with minimal disruption to ongoing industrial activities and no equipment was left on site in between the first two injection phases.