Appendix I – SVE Technology Description

ESTCP (2002) Air Sparging Design Paradigm

ESTCP (2002) based their design paradigm on the conclusion that long-term air sparging performance (cleanup levels and times) cannot be predicted reliably from data collected during short-term pilot tests. As a result, given the importance of air distribution and our inability to predict it, ESTCP proposed an approach where the actual air distribution in the target treatment zone is characterized during the pilot-testing and full-scale implementation phases. Because of their approach, pilot testing and monitoring should be understood in context of the overall design paradigm, which consists of five main steps:

Site characterization and development of site conceptual model
Preliminary feasibility assessment
Pilot testing
Design
Monitoring

The pilot testing is divided into two approaches, 1) standard design approach and 2) site-specific design approach. For each of these two approaches there are default designs and recommended monitoring. The flow chart for air sparging design including pilot testing is shown in Figure B-1.

The standard design approach recommends the following data collection: injection pressure versus flow rate test, transient pressure response test, dissolved oxygen measurements, helium tracer test and soil gas sampling. Based on this data set, injection wells based on 15 ft centers and 20 ft3/min injection rate are recommended. The site-specific design approach recommends the standard methods plus sulphur hexafluoride tracer test to assess air distribution more accurately.

This appendix provides an overview of the technology, site conditions conducive to SVE, generalized site types for applicability of SVE, and SVE design.

Overview of Technology

SVE is the application of a vacuum to unsaturated (vadose zone) soils to induce advective soil vapor flow toward extraction wells and remove volatile and some semi-volatile contaminants from soil. Once removed from the soil, volatile organic compounds (VOCs) are typically removed or destroyed using an aboveground treatment process such as granular activated carbon, or catalytic or thermal oxidation (US EPA 2006). SVE is primarily a composition-based remedy because higher volatility VOCs are removed at greater rates than lower volatility VOCs. Consequently, SVE can be used to target remediation of lighter COCs such as benzene.⁴

The phase change and mass removal typically decrease during the treatment life cycle. During early stages of remediation, the primary mass removal is from air pathways of low resistance (higher permeability soils), where chemicals in adsorbed phase or non-aqueous phase liquids (NAPL) partition into the moving air. Contaminants in lower permeability soils will not be removed by advection because soil vapors will preferentially flow through higher permeability soils. When the mass in higher permeability soils becomes mostly depleted, the rate of mass removal may approach a low value or cumulative mass recovery may approach an asymptotic value. This is because contaminants in lower permeability silts and clays and within the capillary fringe, if present, must desorb and diffuse into an advective flow path before they can be removed by the SVE system. If the rate of diffusion is slow, the time duration for removing VOCs may be significantly extended (US EPA 1991). US EPA (2018) describes a two-compartment model (coarse- and fine-grained) for prediction of concentrations and clean-up times when there are mass transfer limitations resulting from slow diffusive transport in fine-grained soil layers.

The addition of air through SVE may result in enhanced aerobic biodegradation and consequently SVE is closely related to bioventing (refer to Bioventing Factsheet). Because there is often contamination at or below the water table, remediation through air sparging will often be an additional component to the SVE system.

Exit Strategy Toolkit

References

Adamski, M.V., Kremesec, R. Kolhatkar, C. Pearson, and B. Rowan. 2005. LNAPL in fine-grained soils: Conceptualization of saturation, distribution, recovery and their modeling. Ground Water Monitoring & Remediation 25: 100-112.

Agarry, S., and G. K. Latinwo. 2015. Biodegradation of diesel oil in soil and its enhancement by application of bioventing and amendment with brewery waste effluents as biostimulation -bioaugmentation agents. Journal of Ecological Engineering 16: 82–91.

Ahlfeld, D.P., A. Dahmani, and W. Ji. 1994. A conceptual model of field behavior of air sparging and its implications for application. Groundwater Monitoring & Remediation 14: 132-139.

Aislabie, J., and J. Foght. 2008. Hydrocarbon-degrading bacteria in contaminated cold soils. In D. Filler, I. Snape, & D. Barnes (Eds.), Bioremediation of Petroleum Hydrocarbons in Cold Regions (pp. 69-83). Cambridge: Cambridge University Press.

Alberta Environment. 2005. Impact of Cold Temperatures on Biodegradation Rates for Natural Attenuation of Petroleum Hydrocarbons. Land Research Users Group, Alberta Environment. Publication Number 809. Edmonton, Alberta. March 2005.

Amos, R. T., K. U. Mayer, B. A. Bekins, G. N. Delin, and R. L. Williams. 2005. Use of dissolved and vapor-phase gases to investigate methanogenic degradation of petroleum hydrocarbon contamination in the subsurface. Water Resources Research, 41, doi:10.1029/2004WR003433.

Amos R. and K. U. Mayer. 2006. Investigating Ebullition in a Sand Column Using Dissolved Gas Analysis and Reactive Transport Modeling. Environmental Science & Technology 40 (17), 5361-5367 DOI: 10.1021/es0602501

Angert, A., Yakir, D., Rodeghiero, M., Preisler, Y., Davidson, E. A., Weiner, T. 2015. Using O₂ to study the relationships between soil CO₂ efflux and soil respiration Biogeosciences 12: 2089–2099

ANSR (Applied NAPL Science Review). 2011. Diagnostic Gauge Plots. Volume 1, Issue 2, February.

API (American Petroleum Institute). 2001. Methods for Determining Inputs to Environmental Petroleum Hydrocarbon Mobility and Recovery Models. API Publication 4711. Washington, D.C. July 2001.

API (American Petroleum Institute). 2006. API Interactive LNAPL Guide Version 2.0.4. Washington, D.C.

API (American Petroleum Institute). 2007. LNAPL Distribution and Recovery Model (LDRM). Volume 2: User and Parameter Selection Guide. API Publication 4760. Washington, D.C. January 2007.

API (American Petroleum Institute). 2012. BioVapor Users Manual (Version 2.1): A 1-D Vapor Intrusion Model with Oxygen-Limited Aerobic Biodegradation. Washington, D.C. https://www.api.org/oil-and-natural-gas/environment/clean-water/ground-water/vapor-intrusion/biovapor.

API (American Petroleum Institute). 2016. API LNAPL Transmissivity Workbook: A Tool for Baildown Test Analysis. API Publication 4762. Washington, D.C. April 2016. https://www.api.org/oil-and-natural-gas/environment/clean-water/ground-water/lnapl/transmissivity-workbook

API (American Petroleum Institute). 2017. Qualification of Vapor Phase-Related Natural Source Zone Depletion Processes. American Petroleum Institute Publication 4784. Washington, D.C. May 2017.

API (American Petroleum Institute). 2018. Managing Risk at LNAPL Sites. Frequently Asked Questions, Second Edition, Soil and Groundwater Research Bulletin No. 18, Washington, D.C. May 2018, updated May 8, 2019.

ASTM (American Society of Testing and Materials). 1998. Standard Guide for Remediation of Ground Water by Natural Attenuation at Petroleum Release Sites. Applied Testing and Materials. E1943-98(2015). ASTM International, West Conshohocken, Pennsylvania.

ASTM (American Society of Testing and Materials). 2013. Standard Guide for Estimation of LNAPL Transmissivity. ASTM International. E2856–13. ASTM International, West Conshohocken, Pennsylvania.

ASTM (American Society of Testing and Materials). 2016. Standard Guide for Evaluating Potential Hazard as a Result of Methane in the Vadose Zone. E2993–16. ASTM International, West Conshohocken, Pennsylvania.

ASTM (American Society of Testing and Materials). 2020. Standard Guide for Development of Conceptual Site Models and Remediation Strategies for Light Nonaqueous-Phase Liquids Released to the Subsurface. E2531-06. ASTM International, West Conshohocken, Pennsylvania.

ASTM (American Society of Testing and Materials). 2021. Standard Guide for NAPL Mobility and Migration in Sediment – Evaluation Metrics. E3282–21. ASTM International, West Conshohocken, Pennsylvania: ASTM International.

ASTM (American Society of Testing and Materials). 2022. Standard Guide for Application of Molecular Biological Tools to Assess Biological Processes at Contaminated Sites. E3354-22. ASTM International, West Conshohocken, Pennsylvania.

ASTM (American Society of Testing and Materials). 2022. Standard Guide for Estimating Natural Attenuation Rates for Non-Aqueous Phase Liquids in the Subsurface. E3361-22. ASTM International, West Conshohocken, Pennsylvania.

Baser, T., J. S. McCartney, A. Ozdogan-Dolcek. 2019. Thermal Energy Storage in Borehole Arrays Installed in Unsaturated Soils. Advances in Soil Mechanics and Geotechnical Engineering Ebook: From Research to Applied Geotechnics. 7: 374 – 390. DOI10.3233/ASMGE190037

Bass, D.G., N.A. Hastings, and R.A. Brown. 2000. Performance of air sparging systems: A review of case studies. Journal of Hazardous Materials 72: 101-119.

Bass, D.H., Brown, R.A. 1996. Air sparging case study database update. Proceedings of the 1st International Symposium on In Situ Air Sparging for Site Remediation. October 24 and 25, 1996, Las Vegas, NV. INET, Potomac, MD.

Bortoni, F., R. T. Schlosser and M.C. Barbosa. 2019. https://doi.org/10.3390/w11112248Numerical Modeling of Multiphase Extraction (MPE) Aiming at LNAPL Recovery in Tropical Soils. Water 11(11): 2248

Bouchard, D., D. Hunkeler, E. L. Madsen, T. Buscheck, E. Daniels, R. Kolhatkar, C. M. DeRito, R. Aravena and N. Thomson. 2018. Application of diagnostic tools to evaluate remediation performance at petroleum hydrocarbon‐impacted sites. Groundwater Monitoring & Remediation 38: 88–98.

Brewer, R. J. Nagashima and M. Rigby. 2013. Risk-based evaluation of total petroleum hydrocarbons in vapor intrusion studies. International Journal of Environmental Research and Public Health 10: 2441–2467.

Bruce, C.L., I.L. Amerson, R.L. Johnson, and P.C. Johnson. 2001. Use of an SF6-based diagnostic tool for assessing air distributions and oxygen transfer rates during IAS operation. Bioremediation Journal 5: 337-347.

Brusseau, M. L., V. Rohay, and M.J. Truex. 2010. Analysis of soil vapor extraction data to evaluate mass-transfer constraints and estimate source-zone mass flux. Ground Water Monitoring and Remediation 30(3): 57-64.

Cahill, A. G., C.M. Steelman, O. Forde, O. Kuloyo, S.E. Ruff, B. Mayer, K.U. Mayer, M. Strous, M.C. Ryan, J.A. Cherry, and B.L. Parker. 2017. Mobility and persistence of methane in groundwater in a controlled-release field experiment. Nature Geoscience 10: 289-294.

CAL EPA (California Environmental Protection Agency). 2010. Proven Technologies and Remedies Guidance – Remediation of Chlorinated Volatile Organic Compounds in Vadose Zone Soil. California Environmental Protection Agency Department of Toxic Substances Control, Sacramento, California. April 2010.

California State Water Resources Control Board (SWRCB). 2012. Low-Threat Underground Storage Tank Case Closure Policy. Effective August 17, 2012.

Christensen, T. H., P. L. Bjerg, S. A. Banwart, R. Jakobsen, G. Heron, H. Albrechtsen. 2000. Characterization of redox conditions in groundwater contaminant plumes. Journal of Contaminant Hydrology, 45, 165 – 241.

CL:AIRE (Contaminated Land: Applications in Real Environments). 2014. An Illustrated Handbook of LNAPL Transport and Fate in the Subsurface. CL:AIRE Business Centre, Reading, England.

CL:AIRE. 2019. An Introduction to Natural Source Zone Depletion at LNAPL Sites. CL:AIRE Technical Bulletin 20. June 2019. London, UK.

CL:AIRE (Contaminated Land: Applications in Real Environments). 2022. An Illustrated Handbook of LNAPL Transport and Fate in the Subsurface. CL:AIRE Business Centre, Reading, England.

Clayton, W.S. 1998. A Field and Laboratory Investigation of Air Fingering During Air Sparging. Groundwater Monitoring & Remediation 18: 134-145.

Clayton, W.S., B.G. Petri, and S.G. Huling. 2011. Fundamentals of ISCO Using Ozone. In In Situ Chemical Oxidation for Groundwater Remediation, Editors, R.L. Siegrist, M. Crimi, T.J. Simpkin, editors SERDP/ESTCP Series. Springer. pp. 193-232.

Corseuil, H., Monier, A., Fernandes, M., Schneider, M., Cristina, N., do Rosario, M. and Alvarez, P. 2011. BTEX Plume Dynamics Following an Ethanol Blend Release: Geochemical Footprint and Thermodynamic Constraints on Natural Attenuation. Environmental Science & technology. 45: 3422-3429.

CRC CARE (Cooperative Research Center for Contamination Assessment and Remediation of the Environment). 2010. A Technical Guide for Demonstrating Monitored Natural Attenuation of Petroleum Hydrocarbons in Groundwater. CRC Care Technical Report No. 15. September. Newcastle, Australia.

CRC CARE (Cooperative Research Center for Contamination Assessment and Remediation of the Environment). 2015. A Practitioner’s Guide for the Analysis, Management and Remediation of LNAPL. CRC Care Technical Report #34. February. Newcastle, Australia.

CRC CARE (Cooperative Research Center for Contamination Assessment and Remediation of the Environment). 2018a. Technical Measurement Guidance for LNAPL Natural Source Zone Depletion. CRC Care Technical Report #44, Newcastle, Australia.

CRC CARE (Coorperative Research Center for Contamination Assessment and Remediation of the Environment). 2018b. Technology guide: In-situ air sparging. Version 0.1: August.

CRC CARE (Cooperative Research Center for Contamination Assessment and Remediation of the Environment). 2020. The Role of Natural Source Zone Depletion in the Management of Light Non-Aqueous Phase Liquid (LNAPL) Contaminated Sites. CRC CARE Technical Report # 46, Newcastle, Australia.

Davis, G.B., C.D. Johnston, B.M. Patterson, C. Barber, and M. Bennett. 1998. Estimation of Biodegradation Rates Using Respiration Tests During In Situ Bioremediation of Weathered Diesel NAPL. Volume 18, Issue 2, May 1998, Pages 123-13, published on-line February 2007

DeVaull, G.E., I.A.L. Rhodes, E. Hinojosa, and C.L. Bruce. 2020. Petroleum NAPL depletion estimates and selection of marker constituents from compositional analysis. Groundwater Monitoring & Remediation, 40, 44–53.

DiGiulio D.C. and R. Varadhan. 2001. Analysis of water saturation, NAPL content, degradation half-life, and lower boundary conditions on VOC transport modeling: Implications for closure of soil venting system. Groundwater Monitoring and Remediation 21: 83-95.

DiGiulio, D.C., M.L. Brusseau, and V. Ravi. 1998. Use of diffusion modeling to aid assessment of rate-limited vapor transport for SVE. P. 155-160 in Wickramanayake, G.B., and R.E. Hinchee (eds.) Physical, Chemical, and Thermal Technologies: Remediation of Chlorinated and Recalcitrant Compounds, Vol. 1(5). Battelle Press, Columbus, OH. https://cfpub.epa.gov/si/si_public_file_download.cfm?p_download_id=538425&Lab=NRMRL

Dominguez, R.C., J. Leu, and M. Bettahar. 2012. Sustainable wind-driven bioventing at a petroleum hydrocarbon–impacted site. Remediation 22: 65-78.

Downey, D. and R. Miller 1996. Bioventing Performance and Cost Results from Multiple Air Force Sites. Report for US Air Force Center for Environmental Excellence (AFCEE). Brooks AFB, Texas. June.

Drucker. A.S. 2007. Chemical injection using an adjustable depth air sparging system. US Patent US20090069622A1.

Enouy, R., M. Li, M.A. Ioannidis, and A.J.A. Unger. 2011. Gas exsolution and flow during supersaturated water injection in porous media: II. Column experiments and continuum modeling. Advances in Water Resources 34: 15-25.

ESTCP (Environmental Security Technology Certification Program). 2000. Final Report: Natural Pressure-Driven Passive Bioventing Naval Facilities Engineering Service Center September 2000, pp. 70.

ESTCP (Environmental Security Technology Certification Program). 2002. Design Paradigm, Air Sparging: Technology Transfer and Multi-Site Evaluation. ESTCP Project ER-9808. August.

ESTCP (Environmental Security Technology Certification Program). 2004. Natural Pressure Driven Bioventing Cost and Performance Report. CU-9715. Naval Facilities Engineering Service Center. January.

ESTCP (Environmental Security Technology Certification Program). 2006. Design Document for Passive Bioventing. Naval Facilities Engineering Service Center Project ER-9715, Washington, D.C., March 2006.

Farhat, S.K., Newell, C.J., and E.M. Nichols. 2011. Mass-Flux Toolkit to Evaluate Groundwater Impacts, Attenuation, and Remediation Alternatives: User’s Manual Version 2.0. Environmental Security Technology Certification Program.

Fitzgibbons, J., D. Downey, R. Hinchee, and J. Zimbron. 2018. Monitoring of Air Injection Remediation Systems Using Carbon Dioxide Efflux Measurements. 11th International Conference on Remediation of Chlorinated and Recalcitrant Compounds, April 8-12, Palm Springs, CA, USA.

Florida DoS (Department of State). 2010. Florida Administrative Code and Florida Administrative Register Contaminant Cleanup Target Levels, Rule Chapter: 62-777.

Florida DEP, Division of Waste Management, Petroleum Restoration Program. 2005.

Forde, O.N., K.U. Mayer, A.G. Cahill, J.A., Cherry, and B.L. Parker. 2018. Vadose zone gas migration and surface effluxes after a controlled natural gas release into an unconfined shallow aquifer. Vadose Zone J. 17: 1-16.

FRTR (Federal Remediation Technologies Roundtable). 2020. Remediation Technology Assessment Reports.

FRTR (Federal Remediation Technologies Roundtable). 2020. Technology Screening Matrix. Federal Remediation Technologies Roundtable (U.S.) United Environmental Protection Agency. Office of Solid Waste and Emergency Response.

Gaito, S., B. Koons, J. Smith, and A. Kirkman. 2019. Rethinking Bioventing It’s Not Just for BTEX and TPH in Soil. Battelle Bioremediation Symposium, April 14-18, Baltimore, Maryland.

Garg, S, C.J. Newell, P.R. Kulkarni, D.C. King, D.T. Adamson, M.I. Renno, and T. Sale. 2017. Overview of natural source zone depletion: Processes, controlling factors, and composition change, Groundwater Monitoring & Remediation, 37, 62– 81.

Gatsios, E., J. Garcia-Rincon, J.L. Rayner, R.G. McLaughlan, and G.B. Davis. 2018. LNAPL transmissivity as a remediation metric in complex sites under water table fluctuations. Journal of Environmental Management 215: 40-48.

Golder Associates Ltd. (Golder). 2006. Guidance On Assessment of Light Non-aqueous Phase Liquid Mobility for Site Classification Purposes in British Columbia. October 9.

Golder. 2016. Remediation Toolkits. Toolkit 1: Summary of Toolkits and Conceptual Site Model and Case Studies (July 8, 2016); Toolkit 2: Monitoring and Prediction (July 8, 2016); Principal authors: Parisa Jourabchi and Ian Hers.

Golder. 2021. Remediation Toolkits. Toolkit 3: Evaluation of Remediation Technologies for Petroleum Hydrocarbon Sites (April 5, 2021); Toolkit 4: Methods for Sustainable Remediation (April 6, 2021); Principal authors: Ian Hers (Toolkits 3 and 4), Parisa Jourabchi (Toolkits 3 and 4), Francois Beaudoin (Toolkit 4).

Grihalva, V.G., T. Palaia, B. Frank, and R. Hinchee. 2018. A Bioventing System Destroys Multimillions of Pounds of Petroleum Hydrocarbons: An Inquiry into the Mass Removal Mechanisms. 11th Int. Conf. on the Remediation of Chlorinated and Recalcitrant Compounds. April 8-12, Palm Springs, CA.

Hinchee, R.E., and S.K. Ong. 1992. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil. Journal of the Air & Waste Management Association 42: 1305-1312.

Hinchee, R.E. 1994. Air sparging for site remediation. International Symposium on In Situ and On-Site Bioreclamation. Edited by Robert E. Hinchee. Lewis Publishers Boca Raton, Florida. pp. 142.

ITRC (Interstate Technology and Regulatory Council). 2009a . Evaluating Natural Source Zone Depletion at Sites with LNAPL, Technology Overview. Interstate Technology & Regulatory Council Washington, D.C. April 2009.

ITRC (Interstate Technology & Regulatory Council) 2009b. Evaluating LNAPL remedial technologies for achieving project goals. LNAPL-1033 2. Interstate Technology & Regulatory Council, LNAPLs Team, Interstate Technology & Regulatory Council, Washington, D.C. December 2009.

ITRC (Interstate Technology and Regulatory Council). 2010. Use and Measurement of Mass Flux and Mass Discharge. Interstate Technology & Regulatory Council. August 2010. Washington D.C.

ITRC (Interstate Technology and Regulatory Council). 2018. Light Non-Aqueous Phase Liquid (LNAPL) Site Management: LCSM Evolution, Decision Process, and Remedial Technologies. LNAPL-3. Interstate Technology & Regulatory Council. Washington, DC.
Johnson, R., P. Johnson, D. McWhorter, R. Hinchee, and I. Goodman. 1993. An overview of in situ air sparging. Groundwater Monitoring & Remediation 13: 127-135.

Johnson, P. C., and Ettinger, R. A. 1994. Considerations for the design of in situ vapor extraction systems: Radius of influence vs. zone of remediation. Ground Water Monitoring Review. Summer: 123-128.

Johnson, P.C. 1998. Assessment of the contributions of volatilization and biodegradation to in situ air sparging performance. Environ. Sci. Technol. 32: 276–281.

Johnson, P.C., A. Das, and C. Bruce. 1999. Effect of flow rate changes and pulsing on the treatment of source zones by in situ air sparging. Environ. Sci. Technol. 33: 1726-1731.

Johnson, P.C., C.C. Stanley, M.W. Kemblowski, D.L. Byers and J.D. Coltart. 1990a. A practical approach to the design, operation and monitoring of in situ soil-venting systems. Groundwater Monitoring and Remediation 10: 159-178.

Johnson, P.C., M.W. Kemblowski and J.D. Coltart. 1990b. Quantitative analysis for the cleanup of hydrocarbon-contaminated soils by in-situ soil venting. Ground Water 28: 413-429.

Johnson, P., P. Lundegard, and Z. Liu . 2006. Source zone natural attenuation at petroleum hydrocarbon spill sites—I: Site-specific assessment approach. Groundwater Monitoring & Remediation, 26, 82– 92.

Johnston, C.D., J.L Rayner and D. Briegel. 2002. Effectiveness of in situ air sparging for removing NAPL gasoline from a sandy aquifer near Perth, Western Australia. Journal of Contaminant Hydrology 59: 87-111.

Jones, W. R., L. Rock, C. Miller, M. Low, C. Alexander, and A. Bowman. 2021. Groundwater Spatiotemporal Data Analysis Tool (GWSDAT), Version 3.1, July 12, 2021.

Jourabchi, P. and I. Hers. 2013. Modelling Study of Iron and Manganese in Groundwater. Prepared for Society of Contaminated Sites Approved Professionals (CSAP) of British Columbia, October 21, 2013.

Kamath, R., D.T. Adamson, C.J. Newell, K.M. Vangelas and B.B. Looney, B.B., 2010. Passive soil vapor extraction. Savannah River National Laboratory, Aiken, South Carolina. SRNL-STI-2009-00571, Rev. 1.

Kirkman, A.J. 2013. Refinement of the Bouwer-Rice baildown test analysis. Ground Water Monitoring and Remediation 33: 105-110.

Kirkman, A.J., M.R. Adamski, and J.M. Hawthorne. 2013. Identification and assessment of confined and perched LNAPL conditions. Ground Water Monitoring and Remediation 33: 75-86.

Kirkman, A.J. and Koons, B. (2020), Unifying NAPL Drawdown and Transmissivity Testing in Unconfined, Confined, Perched, and Fractured Settings using the Z-Factor and MH Principles. Groundwater Monit R, 40: 47-64.

Klammler, H., K. Hatfield, J. A. G. da Luz, M. D. Annable, M. Newman, J. Cho, A. Peacock, V. Stucker, J. Ranville, S. A. Cabaniss, and P. S. C. Rao. 2012. Contaminant discharge and uncertainty estimates from passive flux meter measurements. Water Resources Research, 48.

Knafla, A., and I. McIvor. 2016. Harnessing wind power for remediation via soil vapour extraction in remote areas. Presentation at Remtech, Banff, AB, Canada.

Khan, A., and R. Zytner. 2013. Degradation rates for petroleum hydrocarbons undergoing bioventing at the meso-scale. Bioremediation Journal. 17: 159-172.

Koons, B., S. Gaito, J. Smith, and A. Kirkman. 2017. Bioventing revisited: Enhanced NSZD outperforms hydraulic LNAPL recovery. Fourth International Symposium on Bioremediation and Sustainable Environmental Technologies, May 22-25, 2017, Miami, Florida.

Kulkarni, P.R., k. L. Walker, C. J. Newell, K. K. Askarani, Y. Li, T. E. McHugh. 2022. Natural source zone depletion (NSZD) insights from over 15 years of research and measurements: A multi-site study. Water Research, Volume 225, 119170, ISSN 0043-1354.

Lahvis, M. A., A. L. Baehr, and R. J. Baker. 1999. Quantification of aerobic biodegradation and volatilization rates of gasoline hydrocarbons near the water table under natural attenuation conditions. Water Resources Research, 35, 753-765.

Lari, K.S., J. Rayner, and G. Davis. 2018. Towards characterizing LNAPL remediation endpoints. J. of Environmental Management 224: 97-105.

Leeson, A., and R.E. Hinchee. 1997. Soil Bioventing, Principles and Practice. CRC, Lewis Publishers, Boca Raton. pp. 272.

Leeson, A., R.E. Hinchee, J. Kittel, G. Sayles, C. M. Vogel and R. N. Miller. 1993. Optimizing bioventing in shallow vadose zones and cold climates.

Hydrological Sciences 38: 283-295.

Lenhard, R.J., K. Sookhak Lari, J. L. Rayner, and G.B. Davis. 2018. Evaluating and analytical model to predict subsurface LNAPL distributions and transmissivity from current and historic fluid levels in groundwater wells: Comparing results to numerical simulations. Groundwater Monitoring and Remediation 38: 75-84.

Li, D. X. 1995. Bioventing feasibility assessment and system design using subsurface oxygen sensors. Journal of the Air & Waste Management Association 45: 762-769.

Liu, M.H., K.H. Li, and B.Y. Chen. 2017. Using bubble respirometer to monitor microbial activity in passive bioventing system. Journal of Environmental Biology 38 (March): 321-326.

Los Angeles (LA) LNAPL Working Group, 2011. Light Non-Aqueous Phase Liquids (LNAPL) Literature Review Version 1.0, Western States Petroleum Association, Torrance, California. October 2011. pp. 75.

MADEP (Massachusetts Department of Environmental Protection). 2016. Light Nonaqueous Phase Liquids (LNAPL) and the MCP: Massachusetts Department of Environmental Protection Guidance for Site Assessment Closure Policy #WSC-16-450. Boston, Massachusetts. February 2016.

Mahler, N., T. Sale, and M. Lyverse. 2012. A Mass balance approach to resolving LNAPL stability. Journal of Ground Water 50: 861-871.

Mayer, K. U., E. O. Frind, and D. W. Blowes. 2002. Multicomponent reactive transport modeling in variably saturated porous media using a generalized formulation for kinetically controlled reactions. Water Resources Research, 38, 13-1 – 13-21.

McAlexander, B., E. Daniels, N. Sihota, J. Eichert, C. Smith. 2014. Multimethod Analysis of NSZD and Enhanced SZD by Solar‐Powered Bioventing at the Guadalupe Restoration Project. Groundwater Monitoring and Remediation. 44(2):72-85

McHugh, T.E., P.R. Kulkarni, C.J. Newell, J.A. Connor, and S. Garg. 2014. Progress in Remediation of Groundwater at Petroleum Sites in California. Groundwater 52: 898–907.

Michigan DEQ (Department of Environmental Quality). 2014. Non-aqueous Phase Liquid (NAPL) Characterization, Remediation and Management for Petroleum Releases. Michigan Department of Environmental Quality Remediation and Redevelopment Division Resource Materials-25-2014-01. Lansing, Michigan, June 2014.

Mohr, D.H. and Merz, P.H. (1995), Application of a 2D Air Flow Model to Soil Vapor Extraction and Bioventing Case Studies. Groundwater, 33: 433-444.

Molins S., K. U. Mayer, R. T. Amos, B. A. Bekins. 2010. Vadose zone attenuation of organic compounds at a crude oil spill site — Interactions between biogeochemical reactions and multicomponent gas transport. Journal of Contaminant Hydrology, 112, 15 – 29.

Montoy, J., K. Hewton and A. Kirkman. 2019. Calculation of Biodegradation Rates above and below the Water Table. Battelle 2019 Bioremediation Symposium Proceedings, Baltimore, Maryland. April 15-18.

Moradi, A., Smits, K.M., Lu, N. and McCartney, J.S. 2016. Heat Transfer in Unsaturated Soil with Application to Borehole Thermal Energy Storage. Vadose Zone Journal, 15: 1-17 vzj2016.03.0027.

Mortensen, A.P., K.H. Jensen, T.O. Sonnenborg, and E. Arvin, E. 2000. Laboratory and numerical investigations of air sparging using MTBE as a tracer. Groundwater Monitoring & Remediation 20: 87-95.

Morris, B.E.L., Henneberger, R., Huber, H. and C. Moissl-Eichingerothers. 2013. Microbial syntrophy: interaction for the common good. FEMS Microbiology Reviews, Volume 37, Issue 3, May, Pages 384–406.

NAVFAC (Naval Facilities Engineering Command). 2001. Air Sparging Guidance Document. NFESC Technical Report TR-2193-ENV. Prepared by Battelle. August 2001.

NAVFAC (Naval Facilities Engineering Command). 2010. LNAPL Site Management Handbook. November 2010. pp. 23.

Nelson, L., J. Barker, N. Li, N. Thomson, M. Iiannidis and J. Chatzis. 2009. A field trial to assess the performance of CO2-supersaturated water injection for residual volatile LNAPL recovery. Journal of Contaminant Hydrology 109: 82-90.

Neriah, B. and A. Paster. 2017. Applying short-duration pulses as a mean to enhance volatile organic compounds removal by air sparging. Journal of Contaminant Hydrology 205: 96-106.

Neriah, A. and A. Paster. 2018. Air Sparging: Enhancing the volatilization of organic compounds through selection of optimized pulsation frequency. Geophysical Research Abstracts 20, EGU2018-2682-1, EGU General Assembly.

Newell, C. J., H. S. Rifai, J. T. Wilson, J. A. Connor, J. A. Aziz, and M. P. Suarez. 2002. Calculation and Use of First-Order Rate Constants for Monitored Natural Attenuation Studies. Ground Water Issue, US EPA National Risk Management Research Laboratory, EPA/540/S-02/500, November 2002.

Ng, C.O., C.C. Mei, and D.W. Ostendorf. 1999. A model for stripping multicomponent vapor from unsaturated soil with free and trapped residual nonaqueous phase liquid. Water Resources Research 35: 385-340.

Ng, G. C., B. A. Bekins, I. M. Cozzarelli, M. J. Baedecker, P. C. Bennett, R. T. Amos, and W. N. Herkelrath. 2015. Reactive transport modeling of geochemical controls on secondary water quality impacts at a crude oil spill site near Bemidji, MN. Water Resources Research, 51, 4156-4183.

Oostrom, M., C. Hofstee, and T.W. Wietsma. 2006. LNAPLs do not always float: An example case of a viscous LNAPL under variable water table conditions. Pacific Northwest National Lab Report Number PNNL-SA-48870. 26th Annual American Geophysical Union Hydrology Days, March 20-22, 2006.

Palaia, T. 2016. Natural source zone depletion rate assessment. Applied NAPL Science Review 6. May 2016.

Praxis Environmental Technologies, Inc. 2000. Demonstration of Characterization Progressing to Remediation (CPR): Beale, Griffis, and Nellis Air Force Installations and Demonstration of Soil Vapor Extraction Optimization: Beale, Castle, George, Mather, McClellan and Norton Air Force Installations. Prepared for Air Force Center for Environmental Excellence.

Qin, X., G. Huang, and H. Yu. 2009. Enhancing remediation of LNAPL recovery through a response-surface-based optimization approach. Journal of Environmental Engineering 135: 999-1008.

Qin, C.Y., Y.S. Zhao, L.L. Li, and W. Zheng. 2013. Mechanisms of surfactant-enhanced air sparging in different media. J Environ Sci Health A Tox Hazard Subst Environ Eng. 48: 1047-1055.

Remediation Technologies Development Forum (RTDF). 2005. “The Basics” Understanding the Behaviour of Light Non-aqueous Phase Liquids in the Subsurface. Prepared by the Non-Aqueous Phase Liquid (NAPL) Cleanup Alliance. February.

RETEC Group, Inc. (RETEC) 2006. Passive Bioventing Pilot Study Report BP Former Refinery Casper, Wyoming. RETEC Project Number: BPG12-19260-630. Prepared for and Property of: BP Products North America, Inc. February 23. Summarized in: Zenker, M. J., G. Brubaker, D.S. Shaw and S.R. Knight. (unknown date) Passive Bioventing Pilot Study at a Former Petroleum Refinery.

Reyenga L. 2021. Typical Metrics for Evaluating Advective NAPL Movement in Sediments. Applied NAPL Science Review, 9, August 2021.

Reyenga, L. 2016. Estimating Expected Ultimate Recovery. Applied NAPL Science Review 6 (2), July.

Ricker, J.A. 2008. A practical method to evaluate ground water contaminant plume stability. Ground Water Monitoring & Remediation, 28, 85 – 94.

Romanak, K. Bennet, P. Yang, C. and Hovorka, S. 2012. Process- based approach to CO2 leakage detection by vadose zone gas monitoring at geologic CO2 storage sites. Geophys. Res. Letters. 39: L15405.

Romanak, K., C. Yang and J.P. Nicot. 2016. Modelling Near-Surface Processes. Presentation at IEAGHG 2nd Combined Meeting of the Modelling and Monitoring Networks, Edinburgh, Scotland, July 6-8.

Roy, J.W., H.C. McLeod, M. Suchy, and J.E. Smith. 2017. Total dissolved gas pressure measurements for assessing contaminant degradation processes in groundwater. Ground Water Monitoring and Remediation 37: 67-77.

Sawyer, C.S. and M. Kamakoti. 1998. Optimal flow rates and well locations for soil vapor extraction design. Journal of Contaminant Hydrology 32:63–76.

Shell (Shell Oil Products US). 2007. Oxygen Pulse Injection System (OPIS): Design and Installation Guidance Document, November 2007 Update.

Shewfelt, K., H. Lee, and R.G. Zytner. 2005. Optimization of nitrogen for bioventing of gasoline contaminated soil. J. Environ. Eng. Sci. 4: 29–42.

Smith, J.J., Gaito, S.T. and B.W. Koons. 2023. Bioventing revisited: efficacy of enhanced biodegradation for si>tes with mobile LNAPL. Quarterly Journal of Engineering Geology and Hydrogeology 2023;56 (2): qjegh2022–085. doi.

Sookhak Lari, K. C.D. Johnston and G. Davis. 2015. gasoline multiphase and multicomponent partitioning in the vadose zone: dynamics and risk longevity. Vadose Zone J.

Sookhak Lari, K., Johnston, C. D., Rayner, J. L., Davis, G. B. 2018. Field-scale multi-phase LNAPL remediation: validating a new computational framework against sequential field pilot trials. Journal of Hazardous Materials, 345, 87–96.

Sookhak Lari, K., G. B. Davis, J. L. Rayner, T. P. Bastow, G. J. Puzon. 2019. Natural source zone depletion of LNAPL: A critical review supporting modelling approaches, Water Research, 157, 630 – 646.

Strasert, B., C. Newell, P. de Blanc, P. Kulkarni, K. Whitehead, B. Sackmann, and H. Podzorski. 2021. Concawe LNAPL Toolbox, Concawe, Brussels, Belgium. Version 1.

Suarez, M.P. and H.S. Rifai. 1999. Biodegradation rates for fuel hydrocarbons and chlorinated solvents in groundwater. Bioremediation Journal 3 (4): 337–362.

Sweeney, R.E., and G.T. Ririe. 2014. Temperature as a tool to evaluate aerobic biodegradation in hydrocarbon contaminated soil. Groundwater Monitoring & Remediation 34: 41-50.

Truex, M. J., D. J. Becker, M. A. Simon, M. Oostrom, A. K. Rice, and C. D. Johnson. 2013. Soil vapor extraction, transition, and closure guidance. Pacific Northwest National Laboratories Report PNNL-21843 RPT-DVZ-AFRI-006. February 2013.

Truex, M. J., C. D. Johnson, D. J. Becker, M. H. Lee, and M. J. Nimmons. 2015. Performance Assessment for Pump-and-Treat Closure or Transition. Pacific Northwest National Laboratories Report PNNL-24696 RPT-DVZ-AFRI-029. September 2015.

Ulrich, A., A.C. Ulrich, K. Tappenden, J. Armstrong and K.W.Biggar. 2010. Effect of cold temperature on the rate of natural attenuation of benzene, toluene, ethylbenzene, and the three isomers of xylene (BTEX). Canadian Geotechnical Journal 47(5): 516-527.

USACE (Army Corp of Engineers). 2002. Engineering and Design: Soil Vapor Extraction and Bioventing. EM 1110-1-4001, U.S. Army Corps of Engineers, Washington, D.C. Last accessed July 17, 2023.

US Army Corps of Engineers (US ACE) 2013. In-situ Air Sparging. EM-200-1-19. December 31.

US AFCEE (US Air Force Center for Environmental Excellence). 2001. Guidance on Soil Vapor Extraction Optimization. Prepared by Parsons for Air Force Center for Environmental Excellence, Brooks AFB, Texas June. June 2001.

US AFCEE (U.S. Air Force Center for Environmental Excellence). 2004. Procedures for Conducting Bioventing Pilot Tests and Long-term Monitoring of Bioventing Systems. Air Force Center for Environmental Excellence Brooks Air Force Base San Antonio, Texas. Prepared by Parsons. May.

US EPA (Environmental Protection Agency). 1991. Soil Vapor Extraction Technology – Reference Handbook. U.S. Environmental Protection Agency Office of Research and Development, Cincinnati, Ohio. EPA/540/2-91/003. February.

US EPA (Environmental Protection Agency) 1994. Manual Alternative Methods for Fluid Delivery and Recovery. U.S. Environmental Protection Agency Office of Research and Development, Washington, D.C. EPA/540/2-91/003. September.

US EPA (U.S. Environmental Protection Agency). 1995a. Bioventing Principles and Practice. Volume I: Bioventing Principles. U.S. Environmental Protection Agency Office of Research and Development, Washington, DC, EPA/540/R-95/534a, September.

US EPA (U.S. Environmental Protection Agency). 1995b. Bioventing Principles and Practice. Volume II: Bioventing Design. U.S. Environmental Protection Agency Office of Research and Development, Washington, D.C., EPA/625/XXX/001, September.

US EPA (Environmental Protection Agency). 1997. Analysis of Selected Enhancements for Soil Vapor Extraction. U.S. Environmental Protection Agency Office of Superfund Remediation and Technology Innovation, Washington, D.C. EPA-542-R-97-007. September.

US EPA (U.S. Environmental Protection Agency). 2005. Ground Water Issue – Light Nonaqueous Phase Liquids. U.S. Environmental Protection Agency Office of Research and Development, Washington, D.C., EPA/540/S-95/500.

US EPA (Environmental Protection Agency). 2006. Off-gas treatment technologies for soil vapor extraction systems: state of the practice. U.S. Environmental Protection Agency Office of Superfund Remediation and Technology Innovation, Washington, D.C. EPA/542/R-05/028. March.

US EPA (Environmental Protection Agency). 2017. How to Evaluate Alternative Cleanup Technologies for Underground Storage Tank Sites. U.S. Environmental Protection Agency Office of Land and Emergency Management 5401R. EPA 510-B-17-003. October.

US EPA (Environmental Protection Agency). 2018. Engineering Issue: Soil Vapor Extraction (SVE) Technology. U.S. Environmental Protection Agency Office of Research and Development, Office of National Risk Management Research Laboratory Land and Materials Management Division. EPA/600/R-18/053. February.

US EPA (US Environmental Protection Agency). 2011. An Approach for Evaluating the Progress of Natural Attenuation in Groundwater. US EPA Report # 600/R R-11/204, December 2011.

US EPA (US Environmental Protection Agency). 2012. Methodology for Understanding and Reducing a Project’s Environmental Footprint. US EPA Office of Solid Waste and Emergency Response. US EPA Report # EPA 542-R-12-002. February. 2012. Washington, D.C.

Viana, P.Z. and K. J. Rockne. 2021. Fundamentals of Ebullition Facilitated NAPL and Contaminant Transport. Applied Science NAPL Review. Volume 9, Issue 6, September.

Vogt, C., Kleinsteuber, S. and Richnow, H.H. 2011. Anaerobic benzene degradation by bacteria. Microb Biotechnol. Nov; 4(6):710-724.

Wisconsin 2015. Guidance for Design, Installation and Operation of In Situ Air Sparging Systems. Department of Natural Resources Report RR-186. February 2015 (Update of 1993 guidance).

Xu, Song, L. Yan, F. Zha, F. Zhu, X. Tan, B. Kang, C. Yang, and Z. Lin. 2022. Remediation characteristics of surfactant-enhanced air sparging (SEAS) technology on volatile organic compounds contaminated soil with low permeability. Journal of Contaminant Hydrology 250, 104049.

Yang, X., D. Beckmann, S. Fiorenza, and C. Niedermeier. 2005. Field study of pulsed air sparging for remediation of petroleum hydrocarbon contaminated soil and groundwater. Environ. Sci. Technol., 39, 7279-7286.

Zamanpour, M.K., R. S. Kaliappan and K. J. Rockne. 2020. Gas ebullition from petroleum hydrocarbons in aquatic sediments: A review. Journal of Environmental Management, 271, 110997, ISSN 0301-4797.

Zhao, W. and M.A. Ioannidis. 2011. Gas exsolution and flow during supersaturated water injection in porous media: I. Pore network modeling, Advances in Water Resources, 34, 2-14.