2007 Ground Water Summit

Wednesday, May 2, 2007 : 8:00 a.m.

Water-Soluble Polymers to Enhance Sweep Efficiencies of In-Situ Remediation Amendments

Jeff A.K. Silva1, Megan M. Smith2 and John E. McCray2, (1)Environmental Science & Engineering Division, (2)Colorado School of Mines

The efficiency of in situ remediation technologies that involve injection of remediation agents into the subsurface is often limited by the ability to obtain an efficient sweep of these amendments within the target zone of contamination.  Poor amendment sweep efficiencies are typically the result of injected amendments seeking preferential flow paths within zones higher permeability.  This leads to by-passing of lower permeability strata and, if sufficient contamination exists within these lower permeability strata, rebounding of contaminant concentrations within a ground water aquifer following treatment.  Methods designed to mitigate the potential for preferential flow and by-passing effects would therefore be highly desirable in the interest of enhancing remediation efficiencies.

One promising approach to mitigate these effects is the addition of water-soluble polymers (e.g., xanthan biopolymers) to remediation amendment formulations.  Water-soluble polymers have been explored for use in the petroleum industry since the 1960’s to enhance oil recovery.  Applied to environmental remediation, the addition of water-soluble polymers has the potential to enhance the sweep efficiency of injected remediation amendments (e.g., chemical oxidants and bioremediation amendments) by promoting transverse fluid movement from zones of high permeability to lower permeability strata.

 In this paper we provide a discussion of the various mechanisms of polymer flow and transport in porous media and present the results of laboratory column experiments used to explore and verify these mechanisms.  We will also provide the results of numerical modeling, using the UTCHEM simulator, used to test the utility of polymer solutions to better distribute remediation agents within heterogeneous porous media.


The 2007 Ground Water Summit