Integrated remedial approach achieves >99% contaminant reduction and prevents future recontamination

The Swedish rail authority required that an entirely in situ remediation strategy be implemented across the largest train maintenance depot in northern Europe, located in Hagalund, Sweden.

The contaminated area was approximately 7,500m2, within which 30,000m3 contaminated soil and groundwater required treatment. As part of the remedial works, Swedish remediation contractor Envytech installed a network of additional monitoring wells across the site. This was done to better delineate the plume and identify any unknown contamination prior to commencement of remediation.

Remediation strategy and products applied:

The investigations identified LNAPL across much of the northern area of the site, which required a revised groundwater remediation strategy comprising:

  • Dual-phase extraction (DPE) to target the LNAPL, followed by;
  • In situ chemical oxidation (RegenOx®);
  • Enhanced aerobic bioremediation (ORC-Advanced®); and
  • Adsorption & biodegradation (PetroFix®).

Case study highlights:

  • Carefully designed integrated remediation strategy used physical, chemical, sorptive and biological treatment
  • Innovative use of PetroFix Permeable Reactive Barriers (PRBs) completed to prevent residual contaminant egress from outside of the treatment area and protect against future spills
  • Significant reductions of petroleum hydrocarbons have been achieved onsite – starting with LNAPL and reaching stringent target values – within nine months