Education

-M.S. (Hydrology) University of Arizona, 1989
-B.S. (Geosciences) University of Arizona, 1980

Registrations/Certifications

Registered Professional Geologist, Utah Registration Number 5336166-2250
Member, National Groundwater Association
Member, Phi Kappa Phi (Honorary Society)
OSHA 40-Hour Health and Safety Training for Hazardous Waste Operations, 1989
8-Hour HAZWOPER annual refreshers

Representative Experience

• Numerical modeling of a baro-pneumatic landfill gas generation rate measurement technique to support a (successful) patent application. Use of the technique to estimate landfill gas generation rates in landfills located in Tucson, Arizona, Albuquerque, New Mexico, Livermore, California, St. Landry’s Parish, Louisiana, Lake Worth in Florida, and several sites in Georgia. Two of the Tucson, Arizona landfills are located within state superfund (WQARF) sites.

• Numerical modeling of the decomposition of municipal solid waste under both aerobic and anaerobic conditions. Model results were used to support the design of an in-situ pilot aerobic treatment system for a closed City of Tucson landfill and to predict long term methane generation rates for untreated landfills.

• Use of the baro-pneumatic method to design landfill gas migration control systems for a site in Payson, Arizona, and several sites in Georgia. Involves use of numerical models to optimize and simulate conceptual design performance.

• Design of biosparging and bioventing systems for cleanup of soils and groundwater impacted by liquid phase petroleum hydrocarbons at the Sky Harbor Airport in Phoenix, Arizona. Work has included use of numerical biodegradation models to interpret field and pilot test data, to design a full-scale site bioventing system, and to design a large scale biosparging test system for the site.

• Management of a groundwater remediation project at an Albuquerque, New Mexico landfill site. Project elements include estimation of landfill gas generation rates, conceptual design of a soil vapor extraction (SVE) system to remove VOC from soils underlying the landfill that act as a continuing source to groundwater, and preliminary design of a groundwater pump and treat system.

• Design of deep soil vapor extraction (SVE) systems for protection of groundwater beneath three Tucson, Arizona landfills. Two of the landfills are within WQARF sites. Systems were configured to maximize removal of deep vadose zone volatile organic compounds (VOC) that have acted as a source to groundwater while minimizing air intrusion into the overlying landfill. The design process included the use of three-dimensional numerical gas flow and transport models that utilized estimates of soil properties derived from field air permeability tests.

• Optimization of the design of a groundwater extraction and treatment system used to remediate groundwater VOC contamination at a Tucson landfill. Numerical flow and transport models were used to enhance the design to meet the client’s need for more rapid cleanup.

• Use of numerical flow and transport models to determine the number of septic systems that can safely be used at proposed residential property developments without excessive nitrogen impacts to groundwater. Use of septic systems at some of the sites were considered in the analysis.

• Management of an investigation at a uranium mill site in Utah to support the award of a groundwater discharge permit. Elements of the project include measurement of soil and bedrock hydraulic properties, numerical modeling to select appropriate monitoring well densities, investigation of a localized groundwater VOC plume, and presentation of results to and negotiation with controlling regulatory agencies.

• Development of a three-dimensional numerical model of groundwater flow through a fanglomerate drinking water aquifer located in central Arizona. The modeling was part of an ongoing remedial effort at an Arizona WQARF site. The model was used to predict the hydraulic interaction between the fanglomerate and an overlying alluvial aquifer impacted by acid mine drainage under pre-remedial conditions and under conditions of anticipated future remedial pumping of the alluvial aquifer.

• Management of an SVE design study at a U.S. Environmental Protection Agency Superfund site located near Gary, Indiana. Work included performance of a pilot test, design of an SVE remedial system for the site using numerical models, and preparation of a design report. The effects of biodegradation resulting from SVE operation were included in the evaluation. The system is currently operating within design parameters.

• Numerical modeling of unsaturated flow and transport within mine tailings impoundments at a copper mine (WQARF site) in Arizona and a Trona mine in Wyoming. Three-dimensional numerical models have been used to: 1) predict the impact of past and current wet tailings disposal on regional groundwater, 2) assess remedial options, 3) direct further data collection activities, and 4) provide data for slope-stability studies.

• Development of a three-dimensional numerical flow and transport model to predict the effectiveness of various remedial pumping strategies on acid mine drainage at a WQARF site in Arizona.

• Hydrogeologic assessment of a mountainous terrain for a Native American tribe in Nevada. Work included estimation of sustainable water supply and water quality, and recommendation of areas most favorable for water development.

• Analysis of multi-depth soil gas data collected at a municipal landfill located within a WQARF site in Tucson, Arizona. Work included supervision of field activities and development of numerical flow and transport models that incorporate groundwater and soil gas data as an aid to understanding past history and current and potential future impacts of VOCs on groundwater.

• Supervision and analysis of an SVE/air sparging pilot test at the site of a gasoline release in Phoenix, Arizona. Work included preparation of site-specific work plans, quality assurance project plans, health and safety plans, and analysis and interpretation of field data using numerical models.

• Management of a remedial investigation at a U.S. Environmental Protection Agency Non-Time Critical Emergency Response site located in Fort Wayne, Indiana. Work has included investigation of on- and off-site subsurface VOC contamination and preliminary design of a soil and groundwater remedial system.

• Numerical modeling to predict the performance of an SVE system to remediate a gasoline spill in Tucson, Arizona, as part of an emergency response action.

• Evaluation of the effectiveness of a large-scale deep bioventing system designed to control VOC migration from a shallow perched water zone to the underlying Ogallala aquifer at a site in the Texas Panhandle. The evaluation included the use of numerical flow and transport models that simulate biodegradation. An interpretive report was prepared that recommended minimum air circulation rates needed to meet remedial goals.

• Supervision of the design of an SVE system to remediate a VOC-contaminated Superfund site located in Kalamazoo, Michigan. Work included preliminary system design using numerical models.

• Assessment of the long-term impact of vadose zone VOCs on groundwater at a site located within the North Indian Bend Wash Superfund site in Phoenix, Arizona. Work included use of numerical models and preparation of an interpretive report.

• Supervision of the design and installation of an SVE/Enhanced Bioremediation System for clean-up of a fuel oil spill in Phoenix, Arizona. Work included predictive numerical modeling of vapor extraction and biodegradation efficiency for the purpose of pilot test design, performance of a pilot test, interpretation of pilot test results, preparation of interpretive reports, and recommendations for a full-scale design.

• Supervision of an investigation of subsurface contamination by organic compounds at a Superfund site in the Livermore Valley, California. Duties included planning and direction of soil gas, soils, and groundwater work.

• Supervision of the investigation and remediation of tetrachloroethylene soil contamination at a site located within the San Gabriel Basin Superfund site, southern California. Duties included planning and direction of field activities, design of remedial alternatives, and preparation of interpretive reports.

• Biostimulation soil venting pilot tests. Duties included preparation of site-specific work plans, supervision of field operations, performance of venting efficiency and tracer tests, interpretation of results using numerical models, and preparation of interpretive reports. Tests have been conducted at various sites including state and federal superfund sites and a site in the Texas Panhandle.

• SVE pre-design investigations. Duties included supervision of soil gas sampling and soil air permeability tests, and interpretation of results using numerical models.

• Environmental audits. Duties included research and investigation into all aspects of past and present property use which may have an impact on potential site contamination and owner liability, as well as investigation into the possibility of contamination from off-site sources. Preparation of interpretive reports based on the results of research and on-site investigations.

• Acid mine water contamination study at an Arizona WQARF site. Duties included sampling and on-site analysis of groundwater to delineate the extent and type of contamination, supervision of monitor and production well installation, performance and interpretation of aquifer tests, and preparation of interpretive reports.

Prior Experience

Geologist/Geological Engineer:

• Analysis of the hydrogeology of the area surrounding a developing mine site in Nevada through interpretation of geologic maps. Recommendation of areas favorable for development of production wells to serve mining operations.

• Interpretation of geophysical data with respect to lithology and structure. Co-author of in-house report relating to major gold districts basin and range structure (as defined by regional gravity and aeromagnetic data). Development of a statistical model to quantify the spatial association of mineralization to aeromagnetic features.

• Geostatistical ore deposit modeling. Transformation of drill-hole data into engineering models used for mine design and planning, corporate financial planning, and published corporate ore reserve statements. Process required detailed analysis of the geologic environment, and analysis of the statistics and geostatistics of element distribution within an ore deposit, to ensure accurate estimation by kriging or inverse-distance techniques.

• Field acquisition, transcription, reduction, and presentation of data. Use of existing software to load, edit, grid, contour, and image process data on Burroughs mainframe, IBM PC, and COMPAC portables.

• Development of computer software to improve data processing procedures and design of routines to process new types of data sets.

• Research and field examination of areas with potential for bulk-minable gold mineralization. Using satellite imagery, located prospects with potential significant enough to warrant property acquisition.

Mineral Exploration Geologist:

• Responsibilities included research and field evaluation of properties with potential for bulk-minable gold, silver, tin, tungsten, and molybdenum mineralization; preparation of geologic reports and recommendations; supervision of drilling operations; and collection and analysis of geophysical data.

SHORT COURSES:

General Physics Corporation Short Course, "Bioremediation Engineering" November 1992.

Air and Waste Management Association Seminar, "Bioventing and Vapor Extraction: Uses and Application in Remediation Operations", April 1992.

PROFESSIONAL PUBLICATIONS:

Smith, S.J., H.W. Bentley, and K. Reaves. 2006. Systematic Design of Methane Migration Control Systems. Proceedings, 29th Annual SWANA Landfill Gas Symposium, St. Petersburg FL, March 27-30. 18 pp.

Bentley, H.W., S.J. Smith, and T. Schrauf. 2005. Baro-pneumatic Estimation of Landfill Gas Generation Rates at Four Operating Landfills. Proceedings, SWANA’s 28th Annual Landfill Gas Symposium, March 7-10, 2005.

Bentley, H.W., 2004. Baro-pneumatic Method of Estimating Landfill Gas Generation Rates. Abstracts with Program, Annual Conference on Waste and the Environment. March 17 – 19, 2004, Lafayette, Louisiana

Walter, G.R., A.M. Geddis, R. Murray, and H.W. Bentley. 2003. Vapor-phase transport as a groundwater contamination process. Proceedings of the 18th International Conference on Solid Waste Technology and Management, Philadelphia, Pennsylvania, March 23-26, 2003.

Bentley, H.W., S. Smith, J. Tang, and G.R. Walter. 2003. A Method for Estimating the Rate of Landfill Gas Generation by Measurement and Analysis of Barometric Pressure Waves. Proceedings of the 18th International Conference on Solid Waste Technology and Management, Philadelphia, Pennsylvania, March 23-26, 2003.

Bentley, H.W., G.R. Walter. S.J. Smith., J. Tang, and C.T. Williamson. 2002. (US) Patent No. US 6,611,760 B2 Method and system for estimating gas production by a landfill or other subsurface source, June 19, 2002.

Walter, G.R., S. Smith, H.W. Bentley, and J. Tang. 2002. Comparison of direct techniques for estimating LFG generation rates. Abstracts with Program. SWANA Regional Landfill Conference, Casa Grande.

Bentley, H.W. and S.J. Smith. 1998. Soil Vapor Extraction of Chlorinated VOCs in the Vicinity of a Landfill Equipped with a Landfill Gas Control System. Presentation at the 1998 Arizona Hydrological Society Eleventh Annual Symposium. September 23 to 26, 1998. Abstract with Proceedings.

Bentley, H.W., J. Tang, S.J. Smith, D. Samorano, R.G. Arnold. 1998. Analysis of Remedial Options for Chlorinated VOCs at Harrison Landfill. In: Bioremediation and Phytoremediation, Chlorinated and Recalcitrant Compounds. The First International Conference on Remediation of Chlorinated and Recalcitrant Compounds. Monterey, California, May 18 to 21, 1998. pp. 21-26

Ward, J.J. and S.J. Smith. 1998. Arid Zone Landfills: What Do Investigation and Modeling of Containment Migration Reveal About Transport Mechanisms? Presentation at the 1998 Arizona Hydrological Society Eleventh Annual Symposium. September 23 to 26, 1998. Abstract with Proceedings.

Smith, S.J., J. Pepe, and G.R. Walter. 1995. The Effect of Variable Injection Rates on Air Sparging Patterns in Heterogeneous, Porous Media. Presented at the First International Symposium on In-Situ Air Sparging for Site Remediation. Las Vegas, Nevada.

Smith, S.J. and G. Walter. 1993. Numerical Modeling of “Raining” Soil Vapor Extraction Wells for a Hypothetical Alluvial Aquifer. Presented at Rocky Mountain Ground Water Conference - Ground Water Technology and Tasks in the 90's, Albuquerque, New Mexico, 1993.

Walter, G.R., R.D. Philip, and S.J. Smith. 1993. Chicken/Egg Arguments in the Establishment of Soil Cleanup Standards. Presented at Hazmacon '93, San Jose, California.