Development of innovative technologies for the remediation of DNAPL source zones throughout their lifecycle
« All Publications

Despite decades of research devoted to the investigation and remediation of chlorinated solvent dense non-aqueous phase liquids (DNAPLs), the remediation community still struggles in achieving closure.

One of the reasons is that remediation techniques are often applied at the wrong stage in a DNAPL site lifecycle. In the earlier stages of a DNAPL site lifecycle, conditions are characterized by the presence of pools, lenses or stringers of DNAPL in the subsurface; whereas, the later stages are characterized by back diffusion from low-permeability zones and desorption from solids. With recent improved emphasis and understanding on DNAPL site lifecycle and its importance in remediation, several promising remediation techniques have emerged that should help the remediation industry to more effectively remediate DNAPL sites including:

  • STAR (in situ smoldering combustion) has demonstrated near complete destruction of coal tar DNAPL. A modified version of STAR is in development to remediate early/middle stage chlorinated solvent DNAPL sites using emulsified vegetable oil (EVO) as a fuel for the smoldering combustion of DNAPL. The combustion reaction propagates through the contaminated zone in a self-sustaining manner provided a sufficient flux of air is supplied, remediating the soils through a combination of contaminant combustion and volatilization.
  • Electrokinetic (EK) techniques to remediate middle/late stage DNAPL sites. EK uses electrokinetic mechanisms to promote migration of amendments through clays/silts through electromigration, electroosmosis, and/or electrophoresis. EK approaches are not dependent on hydraulic conductivity; therefore, achieving uniform and rapid distribution of amendments in clays and silts. Amendments can include electron donors, electron acceptors, and/or bacteria for in situ bioremediation, or oxidants for in situ chemical oxidation.
  • DPT Jet Injection to address middle/late stage DNAPL sites. DPT Jet Injection emplaces solid amendments through mixing. These methods aid in placing the material in the zone of the source and either destroy the contaminant, or can be used in enhance the hydraulics through the injection of sand.

This presentation will discuss the lifecycle of a DNAPL release, environmental issues to be addressed, and concerns within each of the stages. The technologies will be discussed through an overview of each, their history of development, and a summary of case study and full scale applications.

Publication Summary

  • Geosyntec Authors: Derek Tomlinson, Evan Cox, David Reynolds, Gavin Grant, David Major, Chapman Ross, Neal Durant
  • All Authors: Derek Tomlinson, Evan Cox, David Reynolds, Gavin Grant, David Major, Chapman Ross, Neal Durant
  • Title: Presentations On Demand section of the ACS website
  • Event or Publication: Publication
  • Practice Areas: Contaminated Sites, Environmental Management
  • Citation: 252nd American Chemical Society (ACS) National Meeting & Exposition August 21-25, 2016
  • Date: 2016