Enhanced Natural Attenuation for Source Mass Reduction

Project: Research project

Project Details

Description

Enhanced Natural Attenuation for Source Mass Reduction Using Sulfate for Enhanced Natural Attenuation of BTEX Source Reduction Sulfate reduction often accounts for much of the mineralization of dissolved--phase petroleum hydrocarbons, and sulfate is being added to the sub--surface to accelerate the bioremediation of hydrocarbon plumes. Most of the attention so far is on reducing BTEX concentrations over a wide area that may include the smear zone, as well as in the plume. Another strategy would be to add sulfate to enhance the natural attenuation of the NAPL source area. The benefit of adding sulfate may be to increase the rate of source--mass reduction, the rate of biodegradation of BTEX in the dissolved phase, the rate of biodegradation of metabolic products from BTEX biodegradation, or some combination. Although all mechanisms would improve the rate and effectiveness of in situ bioremediation of BTEX NAPLs, increasing the rate of source--mass reduction should have the greatest benefit in terms of lowering the time and costs of site remediation. While mechanism--based research has not been directed toward the effects of sulfate towards enhanced natural attenuation of BTEX in NAPLs, researchers have created conditions that increase the rate of biodegradation of NAPL components and accelerate source--mass reduction. For example, Seagren et al. (1993, 1994) used modeling to explain how faster biodegradation kinetics near the NAPL--water interface can lower the concentration of dissolved components and increase their mass--transfer rate out of the NAPL. Song and Seagren (2008) and Amos et al. (2008) demonstrated the principle experimentally with naphthalene and tetrachloroethene (PCE), respectively. The over--arching objective of this project is to develop a mechanistic and quantitative understanding of how sulfate reduction accelerates biodegradation of BTEX in NAPL--contaminated aquifers. A special focus is on increasing the rate of source--mass reduction. The research is based on a framework for how sulfate addition could accelerate biodegradation and source--mass loss. Then, proof--of-- concept experiments will be conducted to evaluate if the expected mechanisms are working and to quantify them. Assuming that the mechanisms are proven and look promising, follow up research will involve 2--dimensional flow--cell studies that demonstrate that the mechanisms can be replicated in a more realistic setting and that prove the cause--and--effect relationship between sulfate reduction and accelerated BTEX bioremediation that results in source--mass reduction.
StatusFinished
Effective start/end date2/1/131/31/15

Funding

  • INDUSTRY: Domestic Company: $277,970.00

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