In situ oxidation and associated mass-flux-reduction/mass-removal behavior for systems with organic liquid located in lower-permeability sediments

Abstract

The effectiveness of permanganate for in situ chemical oxidation of organic liquid (trichloroethene) trapped in lower-permeability (K) zones located within a higher-permeability matrix was examined in a series of flow-cell experiments. The permanganate solution was applied in both continuous and pulsed-injection modes. Manganese-oxide precipitation, as confirmed by use of SEM-EDS, occurred within, adjacent to, and downgradient of the lower-K zones, reflective of trichloroethene oxidation. During flow interruptions, precipitate formed within the surrounding higher-permeability matrix, indicating diffusive flux of aqueous-phase trichloroethene from the lower-K zones. The impact of permanganate treatment on mass flux behavior was examined by conducting water floods after permanganate injection. The results were compared to those of water-flood control experiments. The amount of water flushing required for complete contaminant mass removal was reduced for all permanganate treatments for which complete removal was characterized. However, the nature of the mass-flux-reduction/mass-removal relationship observed during water flooding varied as a function of the specific permanganate treatment.

Characterizing long-term contaminant mass discharge and the relationship between reductions in discharge and reductions in mass for DNAPL source areas

“…The data exhibit a curvilinear convex-upward profile that resides above the one-to-one reference line. A few prior CMDR-MR profiles have been reported based on laboratory experiments and mathematical modeling (e.g., Rao et al, 2002; Jayanti and Pope, 2004; Phelan et al, 2004; Jawitz et al, 2005; Fure et al, 2006; Brusseau et al, 2008; Kaye et al, 2008; Maji and Sudicky, 2008; Carroll and Brusseau, 2009; Christ et al, 2009, 2010; Tick and Rincon, 2009; DiFilippo et al, 2010; Marble et al, 2010). The results span a wide range of behavior, from convex-downward curves residing below the reference line (for which there is relatively small reduction in CMD during the early stages of mass reduction), to approximately one-to-one profiles, to convex-upward profiles similar to those observed herein.…”

“…The CMDR-MR relationship is a defining characteristic of system behavior, and is mediated by system properties and conditions such as permeability distribution, contaminant distribution, and mass-transfer processes. These relationships have been characterized in several laboratory and mathematical-modeling studies (Rao et al, 2002; Jayanti and Pope, 2004; Phelan et al, 2004; Jawitz et al, 2005; Fure et al, 2006; Brusseau et al, 2008; DiFilippo and Brusseau, 2008; Kaye et al, 2008; Maji and Sudicky, 2008; Carroll and Brusseau, 2009; Christ et al, 2009, 2010; Tick and Rincon, 2009; DiFilippo et al, 2010; Marble et al, 2010). However, very few measurements of CMDR-MR relationships have been reported to date for field systems (Brusseau et al, 2007; DiFilippo and Brusseau, 2008).…”

Assessment of a simple function to evaluate the relationship between mass flux reduction and mass removal for organic-liquid contaminated source zones

“…This approach has been applied in several studies during the past decade (e.g., Rao et al, 2002; Brooks et al, 2004; Zhu and Sykes, 2004; Falta et al, 2005; Basu et al, 2008a, 2008b; Brusseau et al, 2008; DiFilippo and Brusseau, 2008; Kaye et al, 2008, Maji and Sudicky, 2008; Parker et al, 2008, Chen and Jawitz, 2009, DiFilippo et al, 2010, Marble et al, 2010). The parameter n defines the specific mass-flux-reduction/mass-removal relationship, and is a lumped-process term that incorporates the impact of organic-liquid distribution, flow-field dynamics (e.g., changes in relative permeability), and mass-transfer processes.…”

Application of a Persistent Dissolved-Phase Reactive Treatment Zone for Mitigation of Mass Discharge from Sources Located in Lower-Permeability Sediments

“…Such methods are typically ineffective for sources residing in lower-permeability domains. For example, the results of prior research have shown that standard flood injection of permanganate solution does not fully treat contamination residing in lower-permeability domains (e.g., Seol et al, 2003; Heiderscheidt et al, 2008; Marble et al, 2010). Technologies that can more specifically target the contamination within the lower-permeability domains, such as in-situ thermal or electrokinetic methods, are generally expensive and/or impractical for deeper sources.…”