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Research

Current Projects

Secondary Impacts of In Situ Remediation on Groundwater Quality and Post-Treatment Management Strategies-SERDP Project ER-2129

Overall Project Objective:
Provide an improved understanding of the impacts of relevant in situ remediation technologies on groundwater quality and relevant subsurface processes.

Project Goals:

  • Identify secondary impacts of thermal remediation and anaerobic bioremediation on subsurface conditions and groundwater quality.
  • Establish methodologies to predict the extent of positive and negative post-remediation impacts.
  • Develop strategies to overcome, and potentially take advantage of, secondary impacts to achieve long-term remediation and/or site management objectives.

 

Task 1: Impacts of Thermal Treatment on Groundwater Quality and Combined Remedies

Objective: to identify and quantify byproducts released during thermal treatment.
Approach: a series of batch and column experiments are being completed in which soils and humic materials of varying organic carbon content are heated to representative thermal remediation temperatures (30-90 -C), then sampled to measure release of volatile fatty acids and hydrogen.
Preliminary results: volatile fatty acid release from soils increased with temperature and is likely related to organic carbon content.
Significance: thermal treatment of a contaminated site may improve the effectiveness of bioremediation downgradient of the heated zone by causing bioavailable electron donors to be released from the heated soil.

 



Batch, flame-sealed ampules prepared with
humic or fulvic acid.


Thermal column packed with high-carbon soil upgradient, and low-carbon sand downgradient. The high-carbon soil was heated to thermal remediation temperatures and release of potential electron donors were measured in the unheated downgradient zone.

 

Task 2: Impact of Metal Sulfide Formation and Dissolution on Groundwater Flow and Bioremediation

Objective: to evaluate the effects of iron (II) sulfide formation on sand and soil permeability.
Approach: iron (II) and sulfide solutions were introduced one at a time to a series of 1-D sand or soil columns and aquifer cells to abiotically induce precipitation of colloidal iron (II) sulfide.
Preliminary results: reductions in permeability and/or porosity were measured in all cases; soils with higher organic carbon content were impacted most severely.
Significance: ubiquitous iron (III)- and sulfate-reducing bacteria may be stimulated during biostimulation of dechlorinating bacteria; the resulting elevated levels of iron (II) and sulfide in groundwater may lead to pore clogging and flow bypassing or preferential flow leading to hydraulic isolation of contaminated areas in the subsurface, and thus, hinder remediation efforts.


FeS precipitate formation in columns packed with Webster soil (top) and Groveland Superfund site materials (bottom time lapse).

Top-Aquifer packed with Federal Fine Ottawa sand with an emplaced Appling soil lens; Middle- FeS precipitate formation; Bottom-iron oxide precipitate formation.

 

 

 

Task 3: Impacts of Remedial Strategies on pH and Microbial Reductive Dechlorination

Objective: to evaluate the consequences of pH reductions on reductive dechlorination activity.
Approach: a series of batch and column studies are being completed to evaluate the resilience of organisms that dechlorinate chlorinated ethenes to low pH exposure. In addition, enrichment and isolation efforts seek to identify dechlorinators that perform under lower pH conditions.
Preliminary results: various dechlorinating pure cultures and consortium BDI show highest dechlorination rates and extent at circumneutral pH. Dehalococcoides bacteria (Dhc) showed some dechlorination activity in pH 5.5 medium but did not grow. Recovery of full dechlorination activity and growth is possible following pH adjustment to circumneutral conditions, but prolonged exposure to low pH conditions impacted Dhc resilience. Sulfurospirillum multivorans dechlorinates PCE to cDCE at pH 5.5 and screening efforts identified this type of bacterium at low pH sites where PCE dechlorination occurred.
Significance: knowledge about the response and resilience of key dechlorinators will assist decision-making at sites where low pH impacts the microbial reductive dechlorination process.



 

Awards

  • Marcet, T.F.. First place in the student poster competition for his work on "Coupling thermal treatment with microbial reductive dechlorination for the enhanced remediation of chlorinated ethenes" at the Association for Environmental Health and Sciences (AEHS) Foundation's 31th Annual International Conference on Soils, Sediments, Water, and Energy; Amherst, MA. October 19-22, 2015.
  • Marcet, T.F.. Second prize in the 5th annual Geosyntec Student Paper Competition for his work on "Electron Donor Release during Thermal Incubation of Soils" at the Battelle Ninth International Conference on Remediation of Chlorinated and Recalcitrant Compounds; Monterey, CA. May 2014.

Publications

  • Cápiro, N.L., F.E. Löffler and K.D. Pennell. (2015). "Spatial and Temporal Dynamics of Organohalide-Respiring Bacteria in a Heterogeneous PCE-DNAPL Source Zone." Journal of Contaminant Hydrology. (In press) DOI: 10.1016/j.jconhyd.2015.08.007
  • Cápiro, N.L., Y. Wang, J. K. Hatt, K.D. Pennell and F.E. Löffler. (2014). "Distribution of Organohalide-Respiring Bacteria between Solid and Aqueous Phases." Environmental Science and Technology. 48 (18): 10878-10887 DOI:10.1021/es501320h
  • Fletcher, K.E., J. Costanza, K.D. Pennell, and F.E. Löffler. (2011) "Electron donor availability for microbial reductive processes following thermal treatment." Water Research 45(20): 6625-6636.

Thesis

  • Marcet, T. F., 2014. Secondary Impacts of In Situ Chlorinated Solvent Remediation due to Metal Sulfide Precipitation and Thermal Treatment. Master of Science thesis. Department of Civil and Environmental Engineering, Tufts University; Medford, MA. February 2014.

Invited Lectures

  • Cápiro, N.L., "Secondary Impacts of Thermal Treatment and Anaerobic Bioremediation on Groundwater Quality." CDM-Smith, Cambridge MA; November 12, 2013.
  • Cápiro, N.L., "Secondary Impacts of Thermal Treatment and Anaerobic Bioremediation on Groundwater Quality." Rice University, Department of Civil and Environmental Engineering seminar; Houston, TX; October 18, 2013.

Conference Presentations

  • Marcet, T.F., S.P. Gaeth, N.L. Cápiro, Y. Yang, F.E. Löffler and K.D. Pennell. "Impacts of Iron (II) Sulfide Precipitation on the Permeability of Porous Media." Battelle Third International Symposium on Bioremediation and Sustainable Environmental Technologies; Miami, FL, June 2015.
  • Cápiro, N.L., T.F. Marcet, J. Costanza, Y. Yang, F.E. Löffler, K.D. Pennell. "Characterization of Byproducts Released during Thermal Treatment to Support Reductive Dechlorination." Remediation Technology Summit; Westminster, CO. March 2-4, 2015
  • Marcet, T.F., K.D. Pennell and N.L. Cápiro. "Implications of Iron (II) Sulfide Precipitation on Aquifer Permeability" at the UCOWR-NIWR-CAUHSI conference; Medford, MA. June 18-20, 2014.
  • Cápiro, N. L., T.F. Marcet, Y. Yang, F.E. Löffler and K.D. Pennell. "Secondary Impacts of In Situ Thermal Treatment and Anaerobic Bioremediation on Groundwater Quality." Battelle Ninth International Conference on Remediation of Chlorinated and Recalcitrant Compounds; Monterey, CA. May 2014.
  • Marcet, T. F., N. L. Cápiro, Y. Yang, J. Costanza, F. E. Löffler and K. D. Pennell. "Evaluating the Potential for Thermal Treatment of Soils to Supply Electron Donors to a PCE-to-Ethene Dechlorinating Consortium." Battelle Ninth International Conference on Remediation of Chlorinated and Recalcitrant Compounds; Monterey, CA. May 2014.
  • Marcet, T. F., Y. Yang, J. Costanza, F. E. Löffler, N. L. Cápiro, K. D. Pennell. "Quantification of Electron Donor Release during Thermal Treatment." Battelle Bioremediation and Sustainable Environmental Technologies Symposium; Jacksonville, FL, June 10-13 2013.
  • Yang, Y., T.F. Marcet, N. L. Cápiro, K. D. Pennell, F. E. Löffler. "pH Effects on the Microbial Reductive Dechlorination Process." Battelle Bioremediation and Sustainable Environmental Technologies Symposium; Jacksonville, FL, June 10-13 2013.
  • Cápiro, N.L., K.D. Pennell, T.F. Marcet, F.E. Löffler and Y. Yang. "Secondary Impacts of In Situ Remediation on Groundwater Quality: Metal Sulfide Formation and pH Reduction." Platform at Remediation Technology Summit; Westminster, CO. March 4-6, 2013
  • Cápiro, N.L., K.D. Pennell, F.E. Löffler, Y. Yang and T.F. Marcet. "Secondary Impacts of In Situ Remediation on Groundwater Quality and Post-Treatment Management Strategies." Poster at Gordon Research Conference; Environmental Sciences: Water; Holderness, NH, June 24-29, 2012
  • Pennell, K.D., F.E. Löffler, N.L. Cápiro, Y. Yang, and T.F. Marcet. "Secondary Impacts of In Situ Remediation on Groundwater Quality and Post-Treatment Management Strategies." Platform at Battelle Eighth International Conference on Remediation of Chlorinated and Recalcitrant Compounds; Monterey, CA. May 2012.
  • Pennell, K.D., F.E. Löffler, N.L. Cápiro, Y. Yang, and T.F. Marcet. "Secondary Impacts of In Situ Remediation on Groundwater Quality and Post-Treatment Management Strategies." SERDP/ESTCP Partners in Environmental Technology Technical Symposium & Workshop, Washington, DC, November 29- December 1, 2011.

Project Team:

At Tufts University:

Kurt D. Pennell

Project Director

Natalie L. Cápiro

Co-PI

Tyler F. Marcet

Ph.D. Candidate
At University of Tennessee:

Frank E. Löffler
Co-PI

Yi Yang
Ph.D. Candidate