26th Annual David S. Snipes/Clemson Hydrogeology Symposium · David S.Snipes/Clemson Hydrogeology...

26th Annual

David S. Snipes/Clemson

Hydrogeology SymposiumApril 12, 2018

Earlier boudinage structure folded by isoclinal F2 folds in Tallulah Falls formation along Hwy 281 in North Carolina Stop Two on the 2018 Field Trip

Frances Stephenson Snipes - 1928-2018

Frances Snipes, wife of David S. Snipes, died on January 30, 2018 in Clemson SC. Frances was born on November 30, 1928, in Angier, NC. She went to UNC-Greensboro (then called WC for Women’s College), and majored in education. She became a teacher and sang in night clubs and churches. Frances won third place in the 1950 Miss North Carolina pageant. She had a beautiful voice and won the talent contest segment with her singing.

Frances and Dave met on a bus. She was on her way to sing with a jazz group. He was in the Army and wearing his uniform. When he saw Frances he ran over to sit next to her. Dave spent two years on the front lines in Korea. He and Frances wrote letters while he was away. About six weeks after he returned home, they got married on August 22, 1953. They had four children in four years: Mike - 1954, Anne - 1955, Joy - 1956, and Janice - 1958. Frances went back to teaching in 1960 to support Dave while he was in grad school at UNC.

This is from Joy:

“Mom was everybody’s mother. She was generous to a fault, and she loved socializing. She would talk your ear off. She never met a stranger, and people gravitated to her because of her jolly disposition, her humility, and her beautiful smile. She had an amazing heart. She always supported Dad, and he was very fortunate to have her love and devotion.”

Speaker ScheduleClicking on a title will take you to the talk’s abstract

Time BellSouth Auditorium Meeting Rooms 1/2 Meeting Rooms 3/4

7:30 Registration

Chlorinated Compound

Remediation Moderator: John Haselow

Hydrogeology Moderators: Timothy Daniel &

Christian Pullano

General Remediation Moderators: David Heicher

& Steven Aufdenkampe

8:30Klozur® One: A Built in Soluble Activator with Klozur Hicks, Patrick

Siting Wells in Complex Hydrogeologic Settings Harrigan, Joseph

Identification and Delineation of Weathered Gasoline LNAPL using Laser Induced Fluorescence Technology Heicher, David

8:45

Large-Scale Remediation of TCE Using Abiotic Degradation with ZVI and Enhanced Biological Degradation Kelley, Robert

Defining Ground-Water Movement at Tyndall Air Force Base, Florida Champion, Tom

Overview of State LNAPL Management Strategies Laub, Matthew

9:00

Technologies, Methodologies, Best Practices for Distribution of Liquid and Solid Amendments for Chlorinated Solvent Remediation Eliot, Cooper

Modeling and Designing a Hydraulic Source Zone Isolation System Gebrai, Yoel

Natural Source Zone Depletion at LNAPL Sites Rhine, Elizabeth

9:15

Identification and Recovery of TCE Dense Non-Aqueous Phase Liquid (DNAPL) in Source Area Using Low Cost Methods Foster, John

Mine Water Resource Management-Groundwater Modeling for Planning and Use Dean, Joey

Quantitative Estimation of LNAPL Recovery Endpoints: A Case Study Zenker, Matthew

9:30

Utilizing Bioavailable Absorbent Media (BAM) to Remediate Chlorinated Hydrocarbons in Groundwater Kinsman, Larry

Hydrogeologic and Geomorphic Processes in a Wastewater Spray Irrigated Agricultural System located in a Karstic Seasonably-Cold Climate Daniel, T.J.

In-Situ Geochemical Stabilization (ISGS) for Non-Aqueous Phase Liquid Treatment – Technical Assessment Scalzi, Michael

9:45

Slow Release Multi-Oxidant Cylinders for Remediation of a 1,1-DCE Plume at an Industrial Site in the Uplands of South Carolina Hollifield, Edward

Accuracy Assessment of Conventional Rainfall-Runoff Modeling in Ungauged Basins Hayes, Isaac

Treatment of Coal Tar Using In Situ Smoldering Combustion McMaster, Michaye

10:00

Combined Remedies with Passive Sustained Release ISCO Technology Treatment for Chlorinated Solvents Site in Canada Colgan, Timothy

Effects of Organic Compounds and Ionic Strength on the Fate and Transport of Toxoplasma gondii in Saturated Porous Media Pullano, Christian

Design and Implementation of an Arsenic Phytoremediation Pilot Study at a Wood Treatment/Chromated Copper Arsenate Site Moore, Alan


10:15ISCR Lessons Learned over the Last Decade Haselow, John

Anisotropy of Hydraulic Conductivity in Piedmont Residual Soil and Saprolite Schaeffer, Malcolm

Evaluating Thermal Treatment as a Viable Mechanism for the Remediation of Elemental Mercury Spain, Thomas

10:30 Break/Please move to the Main Ballroom

11:00 Keynote: Groundwater as a Buffer to Climatic Change: Dynamic Subsurface Storage of Glaciated Landscapes, David Boutt, University of Massachusetts-Amherst, 2018 Birdsall-Dreiss Distinguished Lecturer

12:00 Lunch

Bioremediation Moderator: David Freedman

Coastal Plain Hydrogeology Moderator: Bruce Campbell

Change Detection Moderator: Larry Murdoch

1:00

Biodegradation of Chlorobenzenes and Nitrotoluenes at an Industrial Site in South America Silva Lemes, Maria Cristina

Hydrology of the Claiborne aquifer in Southwestern Georgia Gordon, Debbie

Results from New Tensor and Areal Strainmeters for Monitoring Fluid Injection and Withdrawal DeWolf, Scott

1:15

Modeling Microbial Transport in Response to Bioaugmentation for In Situ Bioremediation of 1,4-Dioxane Ramos-Garcia, Angel

The Hydrogeologic Framework Developed for the South Carolina Coastal Plain Groundwater Flow Model Gellici, Joseph

Characterizing Deformation during the Pumping of an Unconfined Aquifer in Pendleton, SC Blais, Riley

1:30

Real Life Data Demonstrating the Success of Bacillus in the Bioremediation of Petroleum Contamination in Soil and Groundwater Lawson, III, Joseph

Groundwater Monitoring Networks at the SCDNR Williams, Joshua

Advancements in Ground Penetrating Radar Array System Technology Facilitate Fast and Economical 3D GPR Surveys Bergstrom, Jorgen

1:45

Implementing Sustainable Remediation via Biostimulation to Expedite Site Closure of a Large Dissolved TCE Plume in Northern Georgia Morris, Kevin

Potentiometric Surface Maps of the South Carolina Coastal Plain Aquifers, November–December 2016 Czwartacki, Brooke

Monitoring Flow in Unsaturated Soils Using Geophysical Sensing Techniques Hundley, Britton

2:00

Influence of Methane Inhibitors and High Molecular Mass Electron Donors on Chlorinated Solvent Biodegradation Ivey, Morgan

Development of a Groundwater Recharge Model for the Coastal Plain of South Carolina using the USGS Soil Water Balance Method Butler, Alexander

Visualizing Subsurface Flow Mechanisms using 4D X-ray Computed Tomography Imaging within a Heterogeneous Porous Media Mamun, Abdullah Al

2:15

Update to the Case Study of Enhanced Bioremediation of PCE in Groundwater using Milk Solution Alexander, Andrew

SC Atlantic Coastal Plain Groundwater Availability Model Campbell, Bruce

A Comparative Study of Wire and Plastic Fiber Optic Cable Extensometers Williams, Reid

2:30 Break

Clicking on a title will take you to the talk’s abstract

Per- and Polyfluoroalkyl

Substances Moderator: Matt Zenker

Remediation Moderator: Joe Rossabi

Geologic Analysis Moderator: Alan Coulson

2:45

Occurrence and Control of Legacy and Emerging Perfluoroalkyl Substances in NC Sun, Mei

Comparative Study for ZVI/Peroxide vs Ferric Iron Oxide Persulfate Activation Followed by Intrinsic Facultative, Biologically Mediated Processes Scalzi, Michael

Using Fossils to Determine the Geologic Origin of the Hagood Millstone (Pickens, SC) Thomas, Morgan

3:00In Situ Containment of PFAS using Colloidal Activated Carbon Northington, Chad

Utilizing Bioavailable Absorbent Media (BAM) to Remediate GRO, DRO, Crude Oil, and PVOC in Groundwater Kinsman, Larry

Mapping Cataclastic Rock Outcrops in Upstate South Carolina to Trace a Possible Brittle Fault Badum, Ryan

3:15

Challenges in the Field and Laboratory to High-throughput PFAS Analysis Somerville, Stephen

Chemical Reduction and Stabilization via Shallow Soil Mixing to Treat CrVI and Lead in Soil in Barranquilla, Colombia Morris, Kevin

Mineralogical Analysis of Volcanic Rocks from the Island of Dominica, Lesser Antilles Hipp, Sawyer

3:30

Application of a PFAS Mobile Laboratory Enables Dynamic Work Strategies at PFAS Site Kelley, Robert

Soil Blending: Amendment Reaction Rates and Soil Strength Recovery Rossabi, Joseph

Comparison Study of CO2 Flux from Two Fields during the Summer Growing Season in Clemson, SC using an EC System Reed, Henry

3:45 Break

Characterization Moderator: Lisa Clark

Vapor Intrusion Moderator: Jim Fineis

4:00

Tools for Monitoring Contaminant Biodegradation when Combined with Colloidal Activated Carbon Northington, Chad

Vapor Intrusion, An overview of current regulation and late breaking research information Fineis, Jim

4:15

Daily Field Updates of 3D Visualization to Optimize Source Area Delineation Kenwell, Amy

Vapor Intrusion Mitigation Technologies & Trends Kleine, Jordan

4:30

Utilization of EPA Method 300 Chromatograms to Track Lactate Distribution in Saprolite and Fractured Rock Aquifer Clark, Lisa

Case Study: Site Characterization of CVOCs Using PSG Samplers Malin, Shaun

4:45

A Novel Remedial Alternative Proposed for the Passive Treatment of Groundwater Discharging from a Coal Ash Disposal Site Alexander, Joseph

Vapor Mitigation System Quality Assurance/Quality Control Hestir, Benjamin

5:15 Mixer at Clemson Outdoor Lab


Clicking on a title will take you to the talk’s abstract

Posters Career Kick-StarterMapping Cataclastic Rock Outcrops in Upstate South Carolina to Trace a Brittle FaultBadum, Ryan

Characterizing Deformation during the Pumping of an Unconfined Aquifer in Pendleton, SCBlais, Riley

Mineralogical analysis of volcanic rocks from the island of Dominica, Lesser AntillesHipp, Sawyer

Radionuclide Waste Disposal: Impact of Plants on Flow, Transport, and Potential Uptake of Uranyl-phosphate in the Vadose ZoneKerschner, Daniel

Treatment Technologies for Separation and Destruction of Per- and Poly-fluorinated Substances (PFAS) in Soil and WaterLiang, Shangtao

Design Verification Program - Lessons Learned from Pre-Application Assessments at In Situ Remediation SitesNorthington, Chad

A Comparison Study of Carbon Dioxide Flux from Two Fields during the Summer Growing Season in Clemson, SC using an Eddy Covariance SystemReed, Henry

Using Fossils to Determine the Geologic Origin of the Hagood Millstone (Pickens, SC)Thomas, Morgan

A Comparative Study of Wire and Plastic Fiber Optic Cable ExtensometersWilliams, Reid

3:00-5:00 in the Main Ballroom

The Career Kick-Starter is a networking event designed to create an opportunity for students to develop a lasting professional network with experts in their field based on shared interests. The Career Kick-Starter is intended to match professionals with a willingness to partner with students who are entering their prospective career field. Some examples of services that mentors have provided in the past include resume review, practice interviews, and introductions to those within the mentor’s professional network. All participation is voluntary.

Quotes from alumni who have attended the Career Kick-Starter in the past:

“My mentor helped me connect with valuable people from different companies I was interested in, how to handle conversations in interviews, what happens when you eventually get a job offer, and how to pick between multiple employment offers.” -Noelia Muskus, Clemson ‘17, Geosyntec Consultants

“I have nothing but the highest praise for the Kickstarter program. The mentor I received through the program helped me immensely in many different ways, which helped me land the job with the top company on my list. Even more than that, I have already been able to share what I’ve learned with other peers of mine from Clemson in their respective job searches.” -Matt Vawter, Clemson ‘17, Hart & Hickman

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Click here to return to the speaker schedule

AbstractsOrdered by last name of first author

Update to the Case Study of Enhanced Bioremediation of PCE in Groundwater Using Milk Solution

Alexander, Andrew, [email protected], and Trevor Benton, Bunnell-Lammons Engineering, Greenville, SC

Releases of perchloroethene (PCE) impacted groundwater at a former textile facility located in the Blue Ridge physiographic province of North Carolina. Enhanced bioremediation of groundwater utilizing milk solution from a nearby dairy facility was evaluated as a low-cost remedial strategy. A laboratory–scale pilot test of this green sustainable technology was performed when the site was transitioned to a brownfield in 2005. A field-scale pilot test was initiated in 2011 which concluded in 2013. The field-scale pilot test included the injection of milk solution into various locations within the contaminant plume. Full-scale remediation began in 2014 and is currently ongoing.

This update will review the site history and the procedures and findings of the laboratory-scale microcosms study. Additionally, the findings of the field-scale pilot test, which had previously only included 2 of 3 injection events, will be reviewed and discussed. A total of 14 monitoring events were performed during the 2-year pilot-scale test.

Full-scale remediation began in 2014 and included the installation of 4 injection wells and the performance of 3 additional injection events. Monitoring includes pre-injection baseline and post-injection sampling at various frequencies including, 30-, 60-, 90-, and 150-day milestones for selected injection and monitoring wells. A total of 15 monitoring events have been performed over the approximate 4 years of full-scale remediation. Monitoring parameters include total organic carbon to gauge both infiltration and utilization of the milk solution within the injection zones and volatile organic compounds to monitor degradation of PCE.

Findings to date include complete degradation of PCE through the transformational pathway to compliance, areas of hydraulic isolation and recalcitrance, creation and dissipation of metabolic by-products including acetone, 2-hexaone, and MEK, creation of high concentrations of daughter products, and confirmation of contaminant flow pathways from observed daughter product migration.

A Novel Remedial Alternative Proposed for the Passive Treatment of Groundwater Discharging from a Coal Ash Disposal Site

Alexander, Joseph, [email protected], Ai-Remedial Systems, Chapel Hill, NC; Patrick Hicks and Gregory Lucier, PeroxyChem, Philadelphia, PA

Improvements to traditional Permeable Reactive Barriers (PRBs) are needed to increase their longevity and to improve their flexibility in treating multiple groundwater contaminants by the passive flow of contaminated groundwater through a variety of commercially available permeable reactive materials (PRMs). PRB longevity is

influenced by site-specific parameters including the effects of hydraulic capture, contaminant residence time with the PRMs, and PRM reactivity.

It is known from international case studies that a common failure mode of conventional PRBs is decreasing permeability through the reactive

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materials over time. Clogging of PRBs can be attributed to silt or sediment, to chemical reactions that precipitate insoluble compounds, or to enhanced microbial activity leading to the growth of algae or other microorganisms that reduce the porosity of the PRMs (Permeable Reactive Barrier, Sustainable Groundwater Remediation by Naidu and Birke, 2015). A reduction in permeability in the gate area can cause groundwater to mound behind the gate and to flow around the funnel. The Interstate Technology & Regulatory Council concluded in their Permeable Reactive Barrier: Technology Update (2011) that hydraulic failures will likely be the “Achilles’ heel” of PRB deployments.

Ai-Remedial Systems, LLC (Ai-RS) set out to overcome the problems associated with conventional PRB installations by developing and patenting novel in-situ technology to contain and treat contaminated groundwater. Solid permeable reactive materials and/or synthetic media are used within replaceable treatment cartridges (RTCs) that are installed below grade inside a system of interlocking mechanical components. The innovation includes: 1) a unique mechanical design that can be driven into the ground (or installed in open trenches or borholes) and tied to conventional sheet piling or slurry walls in a funnel-and-gate configuration; 2) a unique vertical channel and treatment cartridge that offer the flexibility to treat contaminated groundwater, surface water, water draining from sediment, or water from a combination of these sources; 3) the ability to easily exchange RTCs, extending the life expectancy of the remedial system as needed; and 4) ports that can be installed within the remedial system to monitor treatment.

The Ai-RS technology addresses four key problems associated with conventional PRBs: 1) the inability to efficiently exchange PRMs in trenches should laboratory treatability tests and remedial planning fail to accurately predict subsurface geochemical or microbial reactions at a site; 2) disposing of the potentially contaminated

material excavated from trenches; 3) restricted placement of conventional PRBs in downgradient portions of plumes due to their limitations in effectively treating higher concentration source areas; and 4) the inability to rehabilitate areas where mineral precipitation occurs within the PRMs.

The Ai-RS technology can be placed close to source areas for aggressive mass reduction using RTCs at a more frequent replacement interval, at downgradient locations for property boundary control, or in tandem at source locations and downgradient. Skimmer cartridges can be used in conjunction with RTCs for capturing non-aqueous phase liquids. Multiple PRMs can be arranged vertically within an RTC (or within multiple RTCs) to treat multiple, site-specific, and mixed groundwater contaminants. The ability to drive units in unconsolidated materials at suitable sites or to install units within large-diameter boreholes at other sites, reduces waste volumes and lowers disposal costs compared to conventional PRBs.

The stainless-steel well screens set within the large-diameter Filter Piles can be developed or rehabilitated as needed using conventional well-drilling techniques, extending the system’s longevity. The Ai-RS technology also enables monitoring of groundwater quality and system performance before, during, and after treatment directly within the Filter Pile. Monitoring ports can be installed within the RTC itself to monitor the condition of the PRMs inside. The ability to have monitoring ports within the Filter Pile alleviates the need for monitoring wells adjacent to the system. This presentation will outline the hydrogeology of a coal ash disposal site where the Ai-RS technology is being considered for the passive treatment of contaminated groundwater. A cost comparison will be provided for the proposed installation of the Ai-RS technology versus a conventional PRB at the same site. A one-sixth-scale 3-D printed model of the remedial system will be demonstrated.

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Mapping Cataclastic Rock Outcrops in Upstate South Carolina to Trace a Possible Brittle Fault

Badum, Ryan, [email protected], and Scott Brame, Clemson University, Clemson, SC

In metamorphic rock terranes, brittle faulting generally occurs as a shallow, localized expression of stress along shear zones. These faults are often narrow and dip nearly vertical. Over forty brittle faults have been mapped in the upstate of South Carolina and neighboring regions of western North Carolina. These fault features can be identified by the presence of highly deformed rocks including cataclasite and microbreccia.

An outcrop of microbreccia was found at Kite Hill on the Clemson University main campus. Using that as a starting point, several other cataclastic outcrops were identified extending

across the Clemson, Seneca, and Five Forks quadrangles. When mapped, these outcrops form a distinct linear pattern that suggest the presence of a continuous fault feature. This feature follows a SW-NE trend with a bearing of about N75E to N85E with distinct non-cataclastic regions to the north and south of the trend line. Thin section analysis was conducted on discrete samples from selected outcrops to identify representative microscale features of brittle faulting such as syntaxial quartz veining. The region mapped covers about 4 km of continuous outcrops but the fault likely extends further in both directions in offset segments.

Advancements in Ground Penetrating Radar Array System Technology Facilitate Fast and Economical 3D GPR Surveys

Bergstrom, Jorgen, [email protected], GEL Geophysics, Marietta, Georgia

Advanced 3D ground penetrating radar (GPR) imaging array systems have been on the market as an alternative to handheld single channel GPRs for approximately 20 years. Although the image quality with array systems is far superior to single channel GPR, broad market acceptance faced many barriers for geoscientists and subsurface utility consultants due primarily to cost, the level of expertise needed for data acquisition,

and complex data processing and analysis. The Raptor system manufactured by Impulse Radar in Mala, Sweden breaks these barriers due to its easy deployment, and unmatched data collection speed (highway speed for most applications). This presentation will discuss the evolution and recent developments in 3D GPR array technology and present recent case studies utilizing the new technology.

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Characterizing Deformation During the Pumping of an Unconfined Aquifer in Pendleton, SC

Blais, Riley, [email protected], and Lawrence Murdoch, Clemson University, Clemson, SC

Hydromechanical well tests use deformation to characterize aquifers during pumping of a well. These tests have been widely performed in fractured rock, but little work has been performed in an unconfined aquifer. The objective of this project was to characterize deformation in an unconfined saprolite aquifer located in Pendleton, South Carolina. The deformation was characterized by measuring tilt using a two component tilt meter installed in the vadose zone. A pumping test was conducted by pumping a well for 4 hours at a rate of approximately 1.5 gallons per minute. Drawdowns of 2.5 meters in the pumping well were measured and correlated with measureable tilt 9 meters away. The tilt responded abruptly when pumping started and tilt increased rapidly

during the first 45 minutes before changing more gradually during the remaining duration of the test. When the pumping stopped, the tilt abruptly reversed and returned to the initial value prior to pumping. These preliminary tests provided encouraging results that this type of test could be a viable alternative for characterizing unconfined aquifers. Moreover, the strongly observed response in the vadose zone was achieved without having to drill into the saturated zone. The ability to characterize an unconfined aquifer without penetrating the saturated zone has many potential applications including decreasing costs and smoothing out logistics in contaminated sites where characterizing the aquifer can be expensive.

Development of a Groundwater Recharge Model for the Coastal Plain of South Carolina Using the USGS Soil Water Balance Method

Butler, Alexander, [email protected], SCDHEC, Columbia, SC; and Tanner Arrington, SCDNR, Columbia, SC

Understanding groundwater recharge in essential to understanding the groundwater system as a whole. Much time has been spent understanding outputs and storage factors of the groundwater systems while relatively little is known about the distribution of recharge. Utilizing the Soil Water Balance (SWB) available from United States Geological Survey (USGS), South Carolina has attempted to fill in the gap in knowledge about our water resources

The SWB code uses readily available data to generate estimates of the spatial and temporal distribution of recharge. Utilizing a modified Thornthwaite-Mather soil water accounting method the SWB model calculates recharge in a gridded area using climate data and landscape

characteristics. Recharge is calculated for each cell by the model as equal to sources minus sinks minus the change in soil moisture. The sources are precipitation, snowmelt, and inflow; sinks are interception, outflow and evapotranspiration.

Data required to execute the SWB Model are temperature and precipitation, land use classification, hydrologic soil group and soil water capacity. Modules within the SWB code are used to calculate the water-budget components based on user inputs. For the South Carolina Model, inputs were derived from elevation, land use and soil maps from the Natural Resources Conservation Service (NRCS) and Climatic Data from the METDATA dataset available from University of Idaho. Inputs are in the form of GIS datasets that

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were preprocessed utilizing ArcMap and Python scripting.

The benefits of developing the SWB model for South Carolina include an ability to visualize and map areas that are important to recharge of the groundwater systems. The outputs from the SWB model will be used as inputs for the

updated South Carolina Coastal Plain Model currently in development by the USGS and DNR. Utilizing historical and predicted land use and land cover patterns the SWB model can also be used to demonstrate how human influence on the landscape has impacted, or has the potential to impact, South Carolina’s groundwater system.

South Carolina Atlantic Coastal Plain Groundwater Availability Model

Campbell, Bruce, [email protected], USGS, Columbia, SC; Greg Cherry, USGS, Norcross, GA; Jason Fine, USGS, Raleigh, NC; Alex Butler, SCDHEC, Columbia, SC; and Joe Gellici, SCDNR, Columbia, SC

The Atlantic Coastal Plain aquifers and confining units of South Carolina are composed of crystalline carbonate rocks, sand, clay, silt, and gravel and contain large volumes of high-quality groundwater. The aquifers have a long history of use dating back to the earliest days of European settlement in the late 1600s. Although extensive areas of some of the aquifers have or currently (2018) are experiencing groundwater-level declines from large-scale, concentrated pumping centers, large areas of the South Carolina (SC) Atlantic Coastal Plain contain substantial quantities of high-quality groundwater that currently are unused.

Groundwater use from the SC Atlantic Coastal Plain aquifers has increased during the past 70 years as the population has increased along with demands for public supply, industrial, and agricultural water needs. While South Carolina works to increase development of water supplies in response to the population growth, the State is facing a number of unanswered questions regarding availability of groundwater supplies and the best methods to manage these important supplies.

A groundwater flow model of the entire SC Atlantic Coastal Plain was constructed and calibrated to predevelopment (pre-1982), 1989, and 2004 conditions. This model now is considered out of date and needs to be updated before it can be used as a groundwater resources management

tool. A project to update the model began in 2016 and will produce a new version of the SC Atlantic Coastal Plain groundwater model that will be suitable for assisting in the management of South Carolina’s groundwater resources. The updated groundwater model is paired with a model of groundwater recharge (1979-2015) that will significantly improve the understanding of recharge processes in the SC Atlantic Coastal Plain. The updated model activates the entire surficial aquifer layer and includes groundwater base flow to a simulated stream network. Multi-aquifer wells are simulated with a modeling package that better defines the withdrawals from each aquifer.

Model calibration efforts include groundwater levels collected from 6,910 various types of wells (both observation and production) across the study area. Groundwater levels have been collected from the wells ranging in time from the early 1900’s to 2015 and include many wells with multiple measurements. Stream base-flow measurements derived from continuous stream discharge data collected at 45 current and past USGS stream gaging sites are also included in the model calibration effort. Inverse modeling techniques are used to adjust various model parameters, such as horizontal hydraulic conductivity and stream bed conductance values, in an attempt to match the groundwater level and stream base flows within specific calibration criteria.

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Defining Ground-Water Movement at Tyndall Air Force Base, Florida

Champion, Tom, [email protected], AECOM, Greenville, SC

In preparation for issuing a fence to fence remediation contract, the Air Force commissioned a Base-wide conceptual site model for Tyndall AFB. Previous mapping of solvent and petroleum plumes resulted in confusing geometries relative to the understanding of ground-water flow. The possibility of contaminant migration into the deeper Floridan Aquifer, a major drinking-water resource, was also raised. These issues needed to be addressed before a remediation contract could be awarded.

To develop the conceptual site model and address the issues raised, water levels were measured in all monitoring wells on Base regardless of the site with which they were associated. Selected shallow monitoring wells and deep water-supply wells were sampled for stable and radio isotopes and major ions. Geologist logs from previous drilling programs were evaluated and a number of geologic cross sections were developed using sequence

stratigraphy, typically used in the petroleum industry. These techniques were adapted for use in shallow sediments and the types of projects typical of the environmental industry. The Base underground infrastructure was also evaluated for the potential for such items as drainage ditches and buried pipelines to impact ground-water flow. Wetlands, physiography, topography and other features were also included in the analyses.

Through the use of geochemistry, sequence stratigraphy and water-level analyses, the nature of ground-water movement was defined. Geochemical analyses confirmed that shallow ground water was not moving downward into the Floridan Aquifer. The directions of shallow ground-water flow, and changes over time due to varying recharge conditions were also defined and the plume geometry explained. With these analyses complete, a more effective remediation strategy could be developed.

Utilization of EPA Method 300 Chromatograms to Track Lactate Distribution in Saprolite and Fractured Rock Aquifer

Clark, Lisa, [email protected], TRC Environmental Corporation, Greenville, SC

Enhanced Reductive Dechlorination (ERD) is an in situ groundwater remediation technology that involves addition of organic substrates (electron donors) to induce anoxic, reducing aquifer conditions and provide the hydrogen needed by dechlorinating organisms to degrade halogenated contaminants. TRC has employed reductive dechlorination at a PCE/TCE-contaminated NPL site in Cherokee County, South Carolina. ERD nutrient injections are periodically conducted to enhance and maintain suitable geochemical environments within the PCE/TCE plume. Performance monitoring is conducted to evaluate the distribution of ERD nutrients and the

performance of ERD treatment process.

The electron donor used at this site includes sodium lactate solution and other ingredients to support the ERD process. The ERD amendments are injected into the aquifer utilizing permitted injection wells. Historically, groundwater samples were collected and analyzed for volatile fatty acids (VFAs) to assess the distribution and degradation of lactate (lactic acid) within the aquifer. While geochemical indicator parameters (primarily DO and ORP) provided evidence of the effects of the lactate solution in the aquifer, concentrations of VFAs usually dropped below detection levels (25 mg/L) within 3-6 months of the injection,

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preventing further tracking of the VFAs.

During the 2015 ERD injection event, sodium bromide was included in the ERD injection fluids at selected wells to act as a tracer that could be monitored to assess the direction and velocity of lactate/groundwater movement. Periodic monitoring for bromide was conducted. The bromide tracer results were successful in identifying preferred groundwater flow pathways from the wells in which the bromide tracer was added. But, the bromide analyses also yielded an unexpected benefit.

Bromide analyses were performed using EPA Method 300, which quantifies inorganic anions (e.g., chloride, bromide, nitrate, sulfate, and fluoride) by ion chromatography. Samples are passed through a chromatographic column where ion species are separated by different transport rates through the column. The time to pass through (elute from) the chromatographic column is used to identify the ion species by comparison to known standards. The resulting chromatograph displays signal strength (conductivity) versus elution time. A given ionic species elutes over a short time period creating a peak in the chromatogram. A lactate standard wasn’t available for calibration, so the relative ion abundance is represented by conductivity (peak height).

While the specific analysis requested for the tracer study was bromide, the detector for Method 300 measures conductivity and is therefore not limited to the ion species for which it is calibrated. In reviewing the chromatograms for the bromide samples, an unidentified peak was noted in samples collected from or near the lactate injection wells.

This peak eluted immediately following fluoride and well before chloride. Suspecting that this peak might be indicative of lactate, samples of the lactate solution were collected and analyzed by EPA Method 300. The chromatogram displayed a peak at the same retention time as the peak in question, supporting our hypothesis that this peak represents the presence of lactate in the groundwater.

Throughout the bromide tracer study, we continued to collect and analyze groundwater samples for bromide and monitor the size of the “lactate” peak in the samples at various locations over time. Since the instrumentation does not quantify this peak in terms of concentration, the conductivity represented by the peak is manually quantified and serves as a surrogate for concentration. Higher peaks were observed in saprolite injection wells with low groundwater flow rates; low to moderate peaks were observed in transition zone injection wells with higher groundwater flow rates. As anticipated, wells located upgradient of the lactate injection wells or wells distal to the treatment area did not show evidence of a lactate peak on their chromatograms.

By monitoring the well locations using Method 300, the presence or absence of a lactate peak and relative size of the lactate peaks over time provided a line of evidence regarding the distribution and longevity of the injected lactate solution within the aquifer. Used in this manner, the Method 300 chromatograms provided an important line of evidence for demonstrating the efficacy of the selected ERD remedy.

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Combined Remedies Using Passive, Sustained Release ISCO Technology Treatment at a Chlorinated Solvent Site in Canada

Colgan, Timothy, [email protected], and Pamela Dugan, Carus Corporation, Peru, IL; and Grant Walsom, XCG Consultants, Ontario, Canada

XCG Consulting Limited was retained by the owners of a commercial real estate property to remediate impacts related to the property’s former use as a dry-cleaning facility. Historic operations resulted in sub-surface releases of chlorinated solvents, including perchloroethylene (PCE), and its breakdown products, trichloroethylene (TCE), cis&trans-1,2-dichloroethylene (cis1,2-DCE, trans-1,2-DCE), and vinyl chloride (VC). The initial contaminant concentrations in groundwater were in the order of five to 10 times higher than the standards for the given land use. Remediation of this property presented several significant challenges, including:•High concentrations of contaminant species having relatively low remedial target concentrations;•Continued commercial use of the building space overlying the impacted area;•Subsurface utilities in close proximity to the impacted areas;•Shallow water table (~three feet) below the floor slab of the commercial space;•Fine-grained soil conditions, resulting in low hydraulic conductivity, a tendency for contaminants to be retained in the soil matrix, and limited remedial access to contaminated zones due to preferential groundwater flow patterns

Initial remedial activities included in situ chemical oxidation (ISCO) through the advancement of temporary subsurface injection points at interior locations through the concrete floor slab of the building, and at exterior locations through the asphalt surface. Solutions of oxidizing compounds (sodium persulfate and potassium permanganate) were injected at low pressure through the temporary injection points. These remedial activities were generally successful, with contaminant concentrations in groundwater reduced by approximately 50% to 100%. However, residual groundwater impacts persisted due to back

diffusion from fine-grained soil conditions. This resulted in contaminant concentrations exceeding the remediation target of 17 ppb. To address the lingering contamination a passive remedial treatment option was chosen in the form of the sustained-release (SR) plus ISCO technology. The SR+ technology consists of a wax matrix that has oxidants compounds (potassium permanganate and sodium persulfate) evenly dispersed within in the form of a cylinder.

Remedial progress of the slow-release ISCO technology was monitored through periodic collection of water samples and analyses of chlorinated solvents within and near the remaining impacted areas. In addition, water quality parameters were also analyzed such as pH, electrical conductivity, and ORP at monitoring wells. Measurement of field parameters taken before and after the ISCO treatments indicates the conditions in the areas of the remaining groundwater became much more favorable for the oxidation of chlorinated solvents. Immediate and continuing increases in the electrical conductivity and oxidation-reduction potential in the groundwater of the treated areas have been observed, indicating the continued release of oxidizing compounds from the dissolving reagent cylinders. After the application of SR+ technology in 2015, an additional source area was found and treated with sodium permanganate. Following the 2017 injections, groundwater sampling results have shown a sustained decrease in the total mass of chlorinated solvents at the monitoring well locations with the remedial target concentration of 17 µg/L reached and pending site closure. Lessons learned include that a low-cost passive treatment option can be used to complement active remediation activities in a combined remedies approach and assist with addressing the effects of “rebound” and back diffusion of chlorinated solvents from low permeability media.

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Technologies, Methodologies, Best Practices for Distribution of Liquid and Solid Amendments for Chlorinated Solvent Remediation

Cooper, Eliot, [email protected], Cascade Technical Services, Bothell, WA

Everyone agrees that contact of amendments with contaminants for a long enough period for complete destruction is critical to meeting remediation expectations. Based on over 15 years of injection and emplacement experience, Cascade has developed a matrix of site and amendment characteristics to help select delivery approaches and amendment dosing specifications.

Delivery approaches including direct push injection, hydraulic and pneumatic fracturing, injection wells and shallow mixing will be discussed. These technologies will be aligned to site considerations related to amendment physical characteristics, lithology, and depth of target

interval. Additionally, parameters critical to contact through dosing include injection flow rates, pressures, injection volumes and concentrations, persistence and kinetics, radius of influence basis will be addressed in relation to site considerations as well.

Results from hundreds of sites have been condensed into a matrix of delivery applications versus site conditions and multiple amendments. Additionally, lessons learned will be shared which should eliminate uncertainty in delivery specification and design parameters for distribution resulting in better industry performance.

Potentiometric Surface Maps of the South Carolina Coastal Plain Aquifers, November–December 2016

Czwartacki, Brooke, [email protected], S.C. Department of Natural Resources, Charleston, SC, and Andrew Wachob, S.C. Department of Natural Resources, Columbia, SC

The aquifers of the South Carolina Coastal Plain Province are an important water source that supports public, industrial, and agricultural water use throughout the Coastal Plain. The South Carolina Department of Natural Resources routinely measures the static (nonpumping) water level in selected wells completed in the major aquifers in order to define the potentiometric surface (elevation of water within tightly cased wells) of the aquifer. This information is published as contour maps that are used to indicate the general direction of groundwater flow and to identify and assess existing or potential areas of concern related to groundwater withdrawal. Changes in water level indicate changes in groundwater storage, and a comparison of potentiometric maps from different years can reveal long-term changes in aquifer storage owing

to groundwater withdrawals, changes in aquifer recharge rates, and variable climatic conditions.

Water-level measurements of nearly 400 wells made primarily during November and December 2016 were used to construct potentiometric surface maps of three Coastal Plain aquifers in South Carolina, referred to here as: the Tertiary (Floridan and Gordon) aquifers; the Crouch Branch aquifer; and the McQueen Branch, Charleston, and Gramling aquifers. The maps developed from the 2016 measurements were the first to utilize the hydrogeologic framework and aquifer nomenclature defined by Gellici and Lautier (2010), rather than that of Aucott and others (1987). Use of this newer framework resulted in potentiometric maps somewhat different than would have been produced using the older framework, particularly for the McQueen Branch-

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Charleston-Gramling map.

The 2016 Floridan-Gordon potentiometric surface map indicates a generally southeastward groundwater flow, with potentiometric elevations ranging from 282 ft (feet) in Barnwell County to -52 ft in southern Jasper County. Along the coast, water levels in the Gordon aquifer were slightly above sea level in northern Charleston County, but lower than -20 ft in most of southern Charleston County. No cones of depression are seen in South Carolina on this map, but the widespread potentiometric low caused by groundwater pumping in the Savannah, Georgia area continues to impact water levels and groundwater-flow direction in southern Beaufort and Jasper Counties.

The 2016 Crouch Branch potentiometric surface map shows a generally southeastward groundwater flow affected by potentiometric lows in the eastern half of the State. The most prominent feature on the 2016 map is a large cone of depression centered in Georgetown County. Water-level declines also are seen in the Myrtle Beach area of Horry County. Comparing the 2016 Crouch Branch potentiometric surface to the predevelopment water level suggests that, in much of eastern South Carolina, water levels in this aquifer are about 50 to 100 ft below predevelopment levels, and in southern Georgetown County, the water-level decline exceeds 200 ft.

The 2016 McQueen Branch-Charleston-Gramling potentiometric surface map shows a generally southeastward groundwater flow affected by potentiometric lows in Williamsburg, Charleston, and Georgetown Counties.

Potentiometric levels range from more than 450 ft near the Fall Line to -136 ft in Georgetown County. A cone of depression centered at Mount Pleasant in Charleston County has not deepened since 2014, but appears to be expanding inland. Water levels in two Mount Pleasant wells were more than 25 ft lower in 2016 than in 2014. Because the cone of depression in Georgetown County is defined by only one water-level measurement, its true magnitude and extent are largely unknown. Comparing the 2016 McQueen Branch potentiometric surface to predevelopment-water levels suggests that, downdip from the recharge areas and outside of the western edge of the aquifer, water levels have declined 50 to 100 ft below predevelopment levels, and in parts of Charleston and Georgetown Counties, more than 200 ft.

REFERENCES

Aucott, W.R., Davis, M.E., and Speiran, G.K., 1987, Geohydrologic framework of the Coastal Plain aquifers of South Carolina: U.S. Geological Survey Water-Resources Investigations Report 85-4271, 7 sheets.

Gellici, J.A., and Lautier, J.C., 2010, Hydrogeologic framework of the Atlantic Coastal Plain, North and South Carolina, in Campbell, B.G., and Coes, A.L., eds., Groundwater availability in the Atlantic Coastal Plain of North and South Carolina: U.S. Geological Survey Professional Paper 1773, p. 49–162.

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Hydrogeologic and Geomorphic Processes in a Wastewater Spray Irrigated Agricultural System Located in a Karstic Seasonably-Cold Climate

Daniel, T.J., [email protected], Clemson University, Clemson, SC; John Richendrfer, Heather Gall, and Henry Lin, Pennsylvania State University, University Park, PA; and Christophe Darnault, Clemson University, Clemson, SC

Pennsylvania State University has been operating a wastewater irrigation site known as the “Living Filter” continuously since 1962, making it one of the oldest wastewater irrigation sites in operation with an unparalleled wealth of data accumulated over decades. The geology of central Pennsylvania, specifically the Nittany Valley, is comprised of carbonate-derived geologic formations with regionally orientated fracture traces in a SW-NE trend. The presence of fracture traces can produce concentrated areas of high permeability which can result in dolines in areas of easily dissolved rocks such as carbonates. The addition of roughly 1.5 MGD of secondary treated wastewater over cropped and forested lands has resulted in the formation of several suspected subsidence dolines in the area with the same general lineation as the fracture traces. Digital Elevation Models (DEMs) over the past decade indicate a rate of change for the areal extent of the dolines on cumulative order of several thousand square feet. By tracking the dolines over time we can determine whether or not

irrigation using secondary treated wastewater has a significant impact on the regression of dolines. The transmissivity of wells drilled within the bedrock fractures in the unconfined aquifer are 40 to 100 times higher than the values of wells drilled outside of the fractures suggesting that the bedrock fractures can act as preferential flow pathways.

Wastewater is rich in organic matter, nitrate, phosphate, and several other compounds that can seriously effect groundwater quality. Since 1982 nitrate, phosphate, and fecal coliform levels have been monitored in wells in and around the site. By creating a groundwater model that matches previous concentrations we can predict what the contaminant profiles might look like in several different scenarios as the rate of wastewater application to the Living Filter is expected to decrease beginning in the year 2020. By determining the long term impacts of changes to the irrigation rates to the Living Filter we can better understand the effects that might take place on the groundwater quality.

Mine Water Resource Management-Groundwater Modeling for Planning and Use

Dean, Joey, [email protected], OceanaGold Inc. Haile Operation, Kershaw, SC

The use of water resources in mining requires exceptional planning and coordination. Mining in wet climates, such as the south east United States presents challenges to environmentally and physically safe engineering use of water. The Haile Gold Mine site is in a geographically wet region of the southeast. Surface water is used as permitted for haul road dust suppression, where infrastructure allows. However, the mine global water balance shows a deficit in site water resources

for all site water needs, and therefore ground water must be used to supplement the site water needs. Groundwater extraction is also necessary to support a reduced stripping cost. Groundwater that is pumped from depressurization wells is used to support open pit mining by providing water for dust suppression, as well as process use for gland seals in the plant pumps. Well water is permitted as fresh water and is also used to supplement reclaim process water use as well.

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A primer in mine water resource use is discussed here and presents one tool that is becoming common place in mining operations to provide greater support to mine water resource managers. The use of groundwater models in mining operations has grown to become best practice. However, most groundwater models that are used were built to provide permitting support and are calibrated to predict ground water impacts regionally. Other uses for mine groundwater modelling fall under initial mine planning and design, where models show slopes can be depressurized and stripping costs reduced. These models are not well suited to providing good dewatering and production predictions when

zoomed in to the mine operation areas (open pit or underground).

A groundwater model has been developed for the Haile site operations using a software called MicroFEM. This model uses a finite-element mesh and is built with a conceptual hydrogeologic model based on known hydrogeology and new operational observation of pit area geology. The site model serves as a tool for predicting water production for process use and dust suppression, permit compliance and pumping impacts to surface water and neighboring properties, and for mine planning by providing predictions of pit water levels and highwall depressurization for highwall design.

Results from New Tensor and Areal Strainmeters for Monitoring Fluid Injection and Withdrawal

DeWolf, Scott, [email protected], Larry Murdoch, Leonid Germanovich, Stephen Moysey, and Alex Hanna, Clemson University, Clemson, SC

Injecting or removing fluids from reservoirs or aquifers causes deformation that can be used as a diagnostic signal in some cases, while it can interfere with geodetic interpretations in other cases. This has motivated us to develop instrumentation and methods to characterize the strain field resulting from injection and pumping. Four new instruments have been deployed at our field stations near Clemson University and at the Avant Field north of Tulsa, OK. Two use non-contact eddy current transducers configured to measure four components of strain and two tilts to 1 part-per-billion. The other systems are low cost areal strainmeters consisting of an embedded optical fiber that is interrogated using laser interferometry. This strainmeter is designed to be a permanently installed and has a resolution of several parts-per-trillion.

The field sites are designed to characterize strains during pumping or injection over different scales and in different geologic settings. The Clemson field station is underlain by biotite gneiss, a low permeability crystalline rock overlain by moderate permeability, soft saprolite above 30m depth. The water table is at approximately 9m depth. The strainmeters are in the crystalline rock at approximately 40m depth, and pumping occurs in the overlying saprolite. In contrast, wells at the Avant Field site are much deeper. They are approximately 500m deep and completed in a 25-m-thick oil-bearing sandstone. Strainmeters at the Avant Field are at ~30m depth. These two sites provide contrasting approaches to characterizing strain at 30-40m depth. Water is pumped from an overlying formation at the Clemson site, whereas it is pumped from a much deeper underlying

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formation at the Avant Field.

Preliminary results are available from several shut-in and injection tests at the Avant Field. The shut-in was characterized by radial tension and circumferential compression in response to a well approximately 1km from the strainmeter. Injection

was characterized by an increase in tensile strains in both the radial and circumferential directions approximately 220m from the well. These are the expected signals caused by shut-in and injection according to inverse analyses thereby showing that strain signals can be used to estimate reservoir characteristics.

Vapor Intrusion: An Overview of Current Regulation and Late Breaking Research Information

Fineis, Jim, [email protected], Atlas Geo-Sampling Company

Vapor intrusion is becoming more common when conducting environmental assessments. Whether you are conducting a Phase I property assessment or a complex environmental investigation, what are the current guidelines that apply? This presentation will consist of an overview of the two current EPA guidance documents and the applicable

ASTM standards for conducting a vapor intrusion assessment. Additionally, the results of research conducted on behalf of the EPA and other parties on various vapor intrusion issues including tubing type, equilibration time, temporal variations, and more will be covered.

Identification and Recovery of TCE Dense Non-Aqueous Phase Liquid (DNAPL) in Source Area Using Low Cost Methods

Foster, John, [email protected], Stan Golaski, and George Maalouf, Rogers & Callcott Environmental, Greenville, SC

Finding and assessing areas of DNAPL contamination is very challenging in crystalline bedrock aquifers. This process can be time consuming and expensive. We present a cost-effective and efficient mechanism for the identification and recovery of TCE DNAPL in bedrock fractures. Characterization and access to source area groundwater is limited due to the site layout and geology. Specifically, an electrical substation limits access and the aquifer is almost entirely in crystalline bedrock at the source. Early assessments at the site, in and around the former source AST location, found no direct evidence of DNAPL.

Bioremediation was selected as the source remedy based on the success of pilot studies conducted at the site. DNAPL was discovered in

injection wells during installation. The application of bioremediation was reevaluated considering the presence of DNAPL, and HRC products with bioaugmentation cultures remained the preferred remedial option. All recoverable DNAPL was removed using a bottom-intake pump over a 3-month period. Wells were checked for the reappearance of DNAPL at least weekly. After no additional product had been observed for approximately 2 months, injection activities proceeded.

Three months following the injection, DNAPL was discovered in a performance monitoring well immediately downgradient of the injection wells that previously contained DNAPL. Recovery began immediately using a bottom-intake pump. Low-cost methods were employed to optimize

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the recovery rate and ensure the most effective DNAPL recovery effort. These methods were implemented in sequence to verify results obtained in earlier steps. A downhole video camera revealed discoloration at a fracture within the fresh borehole. Subsequently, a FLUTe liner was deployed to evaluate the nature of the discoloration, which confirmed the presence of DNAPL at three depths. The DNAPL stains on the FLUTe liner corresponded to existing fractures in the rock core based on depth measurements and photographs of the rock core. These fractures were isolated using an inflatable packer, and the DNAPL was pumped from the isolated zone. Three months later, using existing appurtenances of a nearby decommissioned SVE system, vacuum was applied to try to induce more DNAPL flow into the well. The addition of the vacuum did not significantly increase the volume of DNAPL recovered.

However, a substantial volume of DNAPL had already been removed.

Keen observation and swift action has resulted in the safe recovery of more than 10 liters of DNAPL (approximately 33 pounds). Simple, low-cost methods, including down-hole video, rock core study and confirmation with a FLUTe liner, were employed to identify the DNAPL-bearing zone. Isolating the DNAPL-bearing fractures with a packer greatly enhanced product recovery. All work was completed within the existing budget and did not interfere with the remedy in place. The effect of the applied vacuum was negligible, likely an indication of depleted DNAPL source. The relatively low cost of this effort and long-term impact on the overall site remediation demonstrate the value of observation and the methods employed.

Modeling and Designing a Hydraulic Source Zone Isolation System

Gebrai, Yoel, [email protected], and Ron Falta, Clemson University, Clemson, SC

Pump and Treat (P&T) techniques remain among the most commonly used methods for groundwater remediation of contaminated sites. Despite its prevalence, the effectiveness of the P&T approach is limited by the chemical properties of the contaminant, heterogeneity, and cost of operation. The environmental footprint, which includes greenhouse gas emissions from energy use and the disruption of an ecosystem over time, is an additional factor that should be given attention when considering P&T.

A potential, more sustainable, alternative to P&T remediation is source zone isolation. Source zone isolation can be achieved by surrounding the contaminant source with a material of contrasting permeability. The construction of an impermeable barrier, such as a sheet pile or slurry wall, is one technique that can be used to contain a contaminant source. However, impermeable barriers must be excavated to a confining layer or

bedrock to be effective and can create a scenario where groundwater mounding takes place. The long-term durability of impermeable barriers is also a concern.

Passive barriers, such as a French drain or constant head moat, may provide a cheaper and more robust means for source zone isolation than an impermeable barrier. A passive barrier acts as a highly permeable region that redirects clean, upstream groundwater around a source zone. The contaminant source is essentially hydraulically isolated and contributions to an existing plume minimized. This study utilizes groundwater flow and contaminant transport modeling to assess the influence of various passive barrier design parameters on source zone isolation. Additionally, different hydrogeologic scenarios for a site are examined to see how the performance of a passive barrier is impacted.

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The Hydrogeologic Framework Developed for the South Carolina Coastal Plain Groundwater Flow Model

Gellici, Joseph, [email protected], S.C. Department of Natural Resources, Columbia, SC

The South Carolina Department of Natural Resources (DNR) is in the process of updating the 2004 South Carolina State Water Plan. As part of the update, a groundwater-availability assessment is being done to determine how much groundwater can safely be utilized in the future. The assessment includes an update of the Coastal Plain groundwater flow model that was developed in 2010 by the U.S. Geological Survey and DNR. The model will be used to assess current groundwater availability and to test a range of what-if scenarios, including those addressing increased pumpage, reduced recharge, and conjunctive-use strategies.

The hydrogeologic framework presented herein of the Coastal Plain will be utilized in the update of the model. This hydrogeologic framework incorporates data from old and newly drilled core holes, well clusters, and water wells. In addition, it extends the hydrostratigraphic nomenclature and classification scheme that was developed at the Savannah River Site by Aadland and others (1995) to the entire Coastal Plain. Aquifers and confining units delineated and mapped in the development of this framework utilized geophysical, lithological, sedimentological, and paleontological data from 44 core holes, geophysical and lithological data from 71 water wells, and hydrostatic-head data from 21 well-cluster sites.

In ascending order, the Cretaceous aquifers being modeled are the Gramling, Charleston, McQueen Branch, and Crouch Branch. The Gramling is the basal aquifer of the Coastal Plain and occurs only in the lower half of the Coastal Plain. It is correlated to the Cape Fear aquifer of Aucott and others (1987). The Charleston aquifer overlies the Gramling and also occurs only in the lower half of the Coastal Plain. It is correlated to the downdip Middendorf aquifer of Aucott and others. Paleontology data indicate that updip strata of the Middendorf aquifer is younger than downdip strata. Consequently, two separate aquifers were

mapped—the Charleston and the McQueen Branch. Thick clay beds separate the two aquifers. The McQueen Branch correlates with the updip Middendorf aquifer of Aucott and others and occurs over most of the Coastal Plain. It becomes increasingly fine-grained downdip to the point where is ceases to be a viable aquifer in some areas of the Coastal Plain. Overlying the McQueen Branch is the Crouch Branch aquifer. It occurs over most of the Coastal Plain and is correlated to the Black Creek aquifer of Aucott and others.

Carbonaceous clay beds in the lower part of the Paleocene Epoch separate the aquifers of the Cretaceous Period from the overlying aquifers of the Tertiary and Quaternary Periods. In ascending order, the Tertiary/Quaternary aquifers being modeled are the Gordon, Middle Floridan, Upper Floridan and surficial. Overlying the Crouch Branch is the Gordon aquifer. It is correlated to the Tertiary sand aquifer of Aucott and others. It is generally absent east of the Congaree and Santee Rivers as a result of erosion or non-deposition associated with uplift of the Cape Fear Arch. The Middle Floridan overlies the Gordon and is correlated to the lower part of the Floridan aquifer system of Aucott and others. It too occurs only in the western part of the Coastal Plain. Overlying the Middle Floridan is the Upper Floridan aquifer, which is correlated to the upper part of the Floridan aquifer system of Aucott and others. In previous reports (Aadland and others, 1995), the Upper Three Runs aquifer represents the surficial aquifer at the Savannah River Site and surrounding areas. It was mapped in Aiken, Barnwell and Allendale Counties where the confining unit that separates the Upper and Middle Floridan aquifers thins and the two aquifers coalesce. For modeling purposes, however, it was necessary to retain the continuity of the aquifer layers in the framework. As such, the Upper Floridan and Middle Floridan aquifers were extended updip to near the Fall

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Line by delineating and mapping the geologic formation(s) that composes the aquifer. Likewise, the surficial aquifer, which in downdip areas consists mainly of Quaternary units, was extended updip where it includes the late Eocene/Miocene Tobacco Road Formation and the Miocene Upland Unit.

REFERENCES:

Aadland, R.K., Gellici, J.A., and Thayer, P.A.,

1995, Hydrogeologic framework of west-central South Carolina: South Carolina Department of Natural Resources Water Resources Division Report 5, 200 p.

Aucott, W.R., Davis, M.E., and Speiran, G.K., 1987, Geohydrologic framework of the Coastal Plain aquifers of South Carolina: U.S. Geological Survey Water-Resources Investigations Report 85-4271, 7 sheets.

Hydrology of the Claiborne Aquifer in Southwestern Georgia

Gordon, Debbie, [email protected], and Gerard Gonthier, USGS, Norcross, Georgia

The U.S. Geological Survey, in cooperation with the Georgia Environmental Protection Division, conducted a study to define the hydrologic properties of the Claiborne aquifer and to evaluate its connection with the Upper Floridan aquifer in the lower Apalachicola-Chattahoochee-Flint River Basin in southwestern Georgia. Borehole geophysical logs were collected from seven wells throughout the study area and two 72-hour aquifer tests were conducted in Mitchell and Early Counties, Georgia. The data collected from the wells and the aquifer tests, along with pre-existing data, were used to determine extent and properties of the Claiborne aquifer.

The top of the Claiborne aquifer extends from an altitude of about 200 feet above the North American Vertical Datum of 1988 (NAVD 88) in Terrell County, Georgia to 402 feet below NAVD 88 in Decatur County, Georgia. The base of the

aquifer extends from an altitude of about 60 feet above NAVD 88 in eastern Sumter County, Georgia to about 750 feet below NAVD 88 in Decatur County, Georgia. Aquifer thickness ranges from about 70 feet to 400 feet in the study area.

Transmissivity estimates of the Claiborne aquifer range from about 700 to 4,700 square feet per day in the study area. These values are based on three previous aquifer-test analyses, analyses of the two aquifer tests conducted for this study, and five transmissivities estimated from specific capacity tests. Aquifer-test data from Mitchell County, Georgia indicate a small amount of leakage; however, no drawdown was measured in the overlying Upper Floridan aquifer as a result of pumping. This leakage was assumed to be coming into the Claiborne aquifer from the underlying Clayton aquifer, however the Clayton aquifer was not directly assessed as a part of this study.

Siting Wells in Complex Hydrogeologic Settings

Harrigan, Joseph, [email protected], AECOM, Greenville, SC; and Craig Nathe and Paul Schiff, AFCEC/CZOW, Edwards AFB, California

Fractured bedrock settings pose many challenges for the hydrogeologist tasked with positioning monitoring wells. The interplay of varying orientation and extent of fracture zone complicate the definition of groundwater flow zones and

potential contaminant pathways. Techniques such as topographic map and aerial photo stereoscopic lineament analysis and structural data presented in geologic maps help set the stage for defining potential bedrock fracture architecture. Sometimes

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thin surficial sediments such as sand dunes, colluvium, and alluvial fans mask the surface features that indicate the bedrock structure. An additional complication is the variation of the bedrock structure with depth, how the fracture orientations vary vertically.

Once the general location for monitoring wells has been decided the depth interval(s) for the well screens needs to be determined to intercept fracture zones of interest. Core drilling provides direct evidence of the rock and fracture zones encountered at depth. Yet this data is not conclusive evidence of where the flow zones are located. Borehole geophysical logs provide additional data to help the hydrogeologist interpret the depth interval of fracture zones that exhibit favorable locations for screening.

After the well(s) are constructed hydrogeologic data can be collected to further characterize the flow capability of the selected fracture zones. Well development, if properly performed and the results properly collected, can provide the first insight into the hydraulic characteristics of the fracture zone. These results can help guide the pumping rate range for the step test, and as shown in an example, be the basis for the selection of the pumping rate for the pumping test. The results from pumping tests provide key permeability information about the subsurface setting where the well screen is positioned. Sometimes a productive fracture zone is confirmed and other times non-productive fracture zones are confirmed. Both outcomes are useful for the characterization of site subsurface setting.

ISCR Lessons Learned Over the Last Decade

Haselow, John , [email protected], Joe Rossabi, and Steve Markesic, Redox Tech, Cary NC; and Jay Romano, Redox Tech NE, Attleboro MA

Over the past decade or so, many in situ remediation applications using a combination of anaerobic bioremediation and chemical reduction with zero valent iron (ZVI) have been successfully completed. This combined process has been coined as In Situ Chemical Reduction (ISCR) and is defined as the combined effect of fermentation of complex organic carbon sources with chemical reduction with reduced metals, typically ZVI. Redox Tech has completed hundreds of ISCR projects over the last 13 years. The projects have

involved direct injection and soil blending in a wide range of geologic environments, including fractured bedrock, glacial till, saprolite, etc. ISCR has been predominantly used to treat chlorinated alkenes, but it has also been successfully applied for chlorinated alkanes (such as 1,2-dichloroethane, chloroform, carbon tetrachloride, etc) as well as hexavalent chromium and arsenic (when combined with sulfate). Several case studies will be presented that share the lessons learned over the last decade.

Accuracy Assessment of Conventional Rainfall-Runoff Modeling in Ungauged Basins

Hayes, Isaac, [email protected], Stephen Moysey, and Ashok Mishra, Clemson University, Clemson, SC

Flooding costs the United States billions of dollars and results in numerous fatalities every year. From 1980-2017, floods comprised 13% of all billion-dollar disaster events in the U.S. with an average cost of 4.3 billion dollars per flood

event. In 2016 flooding in the U.S. resulted in 126 fatalities. Rainfall-runoff modeling can be used to characterize runoff patterns within a watershed to plan for future flooding events and to understand how changes in land use will affect flood risk.

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Rainfall-runoff modeling in watersheds containing a distributed network of streamflow gauges is a common and straightforward process; however, in watersheds lacking this network of streamflow gauges the process becomes much more complex.

To demonstrate the complexity of this process, SWAT modeling will be performed on a single, ungauged watershed. SWAT is a basin scale model developed to quantify the impact of land use changes on water in complex watersheds. SWAT relies on input of weather, hydrology, soil properties, vegetation properties, and land use data. Many of these inputs are difficult to obtain in ungauged basins. The watershed used in this analysis will be chosen from the MOPEX (Model Parameter Estimation Experiment) network of ungauged basins. The MOPEX network is made up of 438 basins in the US which have hydrometerological data consisting of daily/hourly precipitation, minimum and maximum

temperature, streamflow data, and climactic potential evaporation data for a minimum of 10 years. This data will be used to perform an accuracy assessment of the SWAT model.

To address the complexity of modeling runoff patterns in ungauged basins, a data driven approach to watershed characterization needs to be developed. This approach would use inverse theory with precipitation radar data and a single streamflow gauge at the outflow point of a watershed to derive zones of uniform runoff response within a watershed. Defining these zones of uniform runoff response is crucial for watershed characterization and predicting change in flood risk caused by altered land use characteristics. This data driven approach will create a means for identifying areas of high flood risk in ungauged basins and will inform decision makers about the impacts a specific land use change will have on the flood risk of a region.

Identification and Delineation of Weathered Gasoline LNAPL Using Laser Induced Fluorescence Technology

Heicher, David, [email protected], Dakota Technologies Company, Charleston, SC

Sites with historical gasoline releases (>10 to 20 years) can be particularly challenging for the HRSC practitioner due to varying degrees of LNAPL degradation that may occur. Site-specific hydrogeological, geochemical, and biological conditions all affect the characteristics of the LNAPL source material, making HRSC tool selection even more important when delineating the presence and extent of the source term material.

Three HRSC systems are commonly used at these sites to provide chemical, hydraulic, and lithologic data of the subsurface. The Membrane Interface Probe (MIP) is designed to screen for dissolved-phase petroleum hydrocarbons, halogenated compounds, and methane. Laser Induced Fluorescence (LIF) is used to identify zones of Light Non-Aqueous Phase Liquids (LNAPL) petroleum, while the Hydraulic Profiling Tool (HPT) is used in conjunction with each

of the other tools to determine hydraulic and lithologic properties of the subsurface. All three technologies collect and record data at high resolution to generate large data sets that provide the most comprehensive horizontal and vertical delineation of contamination in the subsurface. Semi-quantitative data are collected, recorded, and subsequently incorporated into data visualization software to generate real-time, 2D-3D graphics revealing plume geometry as an investigation is taking place. The result is a continuous data set with no data gaps such as those that are often experienced with traditional sampling methods due to poor sample recovery.

An overview of how to maximize the benefit of each of these HRSC technologies at legacy LNAPL sites will be provided, along with an examination of LIF and MIP output logs from prior HRSC projects that successfully differentiated source term material from other phases of subsurface impact.

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Vapor Mitigation System Quality Assurance/Quality Control

Hestir, Benjamin, [email protected], Terracon Consultants, Inc. Greenville, SC

The installation of vapor mitigation systems (VMS) to prevent the entry of hazardous vapor phase subsurface contaminants is becoming a common requirement when contaminated real estate is redeveloped. These multi-layer membrane and vapor collection systems are installed early in the construction process, prior to the pouring of foundation slabs. They are designed to provide a preferential pathway to any vapor phase contaminants present in the subsurface allowing

them to be vented at roof height rather than entering and accumulating in buildings, whether residential or commercial. A recent project involving seven separate structures in a mixed-use development in South Carolina has provided an excellent opportunity to identify common problems encountered during the installation process and during the post-construction monitoring.

Klozur® One: A Built in Soluble Activator with Klozur

Hicks, Patrick, [email protected], PeroxyChem, Philadelphia, PA

Activated Klozur® persulfate is one of the most prevalent remedial technologies having been implemented at thousands of sites to successfully remediate contaminated aquifers around the world. The ability to treat a wide assortment of contaminants has been attributed to proper activation of persulfate which can lead to the formation of the sulfate, hydroxyl, or superoxide radicals. These activation methods include iron chelates, alkalinity, heat, zero valent iron, and hydrogen peroxide.

However, due to chemical incompatibilities, the activator reagents have been stored and mixed separately from the Klozur persulfate. This has resulted in typical injection systems that batch the activator reagents and persulfate separately and either mix the two reagents inline just prior to injection or pulse the reagents into the subsurface separately. Having the persulfate and activator delivered as a single bag and mixed into a single solution would simplify the injection system and

blending calculations.

Objectives: The objective of this work was to identify a blended activator-persulfate system that could be safely stored, transported, and batched together while still effectively treating the different contaminants of concern.

This presentation will discuss the existing methods of activating persulfate, conditions used to generate oxidative and reductive pathways, and then review key stability data and treatment efficacy of an all-in-one blend containing Klozur SP and a novel activation system. The stability data will show that the blend can be safely stored and transported. Stability and losses measured over time upon mixing will be compared to that of different organic activators. Finally the treatment efficacy of different activation systems in treating common contaminants of concern such as 1,4-dioxane, TCE, carbon tetrachloride, and benzene will be presented.

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Mineralogical Analysis of Volcanic Rocks from the Island of Dominica, Lesser Antilles

Hipp, Sawyer, [email protected], Scott Brame, Mary Kate Fidler, Clemson University, Clemson, SC

The island of Dominica in the Caribbean has nine potentially active volcanoes and is comprised almost entirely of volcanic rocks. The source of the volcanic rocks is a large magma body of molten rock that formed from friction when the Caribbean Plate collided with the Atlantic Plate about 8 million years ago forming a volcanic island arc. In the beginning only basaltic lava was extruded to form the island but over time the magma body differentiated as lighter elements rose to the top of the magma chamber. As the Atlantic Plate continued to subduct under the Caribbean Plate, molten rock was added to the chamber from the bottom. The increased pressure in the chamber forced the more compositionally light material at the top to the surface to erupt as lava from one of the volcanic centers. This lava reflects the shift

to an andesitic composition. This compositional change is reflected in the pyroclastic flows which have dominated the eruptive style on the island for the last 40,000 years.

Selected samples from outcrops along major roads were collected around the island for petrographic analysis. Thin section analyses reveals that the samples collected from the Roseau ignimbrite have an expected composition of minerals found in andesitic rocks that are typical of volcanic island arcs. The mineral assemblages are mainly plagioclase (50%-70%) with clinopyroxene (10%-20%) and orthopyroxene (5%-15%). Samples representing the basaltic composition of the island core contain altered olivine and one sample had iddingsitized olivine (15%) that was zoning from the inside out.

Slow Release Multi-Oxidant Cylinders for Remediation of a 1,1-DCE Plume at an Industrial Site in the Uplands of South Carolina

Hollifield, Edward, [email protected], and Jennifer Byrd, ERM NC, Charlotte, NC

A slow release oxidant pilot test was conducted at a manufacturing facility in South Carolina to address the dilute downgradient portion of the VOC plume extending from the former hazardous waste surface impoundment. This area of the contaminant plume is being targeted for remediation to prevent off-site migration of the residual dissolved phase contaminant mass that remains in groundwater following source area remediation activities conducted between 1989 and 2005. The remaining VOC plume is defined primarily by low levels of 1,1-DCE in groundwater. The treatment area includes 70 feet of saturated aquifer between the top of the water table and the partially weather rock zone.

Sustained release oxidant was selected for pilot

testing over traditional oxidant delivery methods to minimize the effort required during repeated application. The sustained release oxidant selected for use is the RemOx® SR+ ISCO reagent developed by Carus Remediation. RemOx® SR+ was developed to provide a sustained release source of potassium permanganate and sodium persulfate for soil and groundwater treatment. RemOx® SR+ cylinders consist of approximately 38% solid potassium permanganate and 38% solid sodium persulfate homogenously dispersed within a solid paraffin wax matrix. The wax matrix serves to slow down the instant dissolution of oxidant and allows for slow sustained release into groundwater. The paraffin wax used to entrap the oxidant is a benign material that is biodegradable.

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A total of fifteen 18-inch long multi-oxidant cylinders were placed in seven injection wells in the pilot test area. Each 2-inch PVC injection well was constructed with 30 feet of screen. The injection wells were placed on five foot centers.

Reductions in 1,1-DCE concentration in the pilot test injection wells between 85% and 100% were observed immediately following cylinder emplacement. The 1,1-DCE data collected from the injection wells indicates that the sustained release cylinders are capable of creating a reactive zone where 1,1-DCE is oxidized, and that reactive zone can be sustained for a period of at least 9 months. Visible oxidant was present at distances up to 30 feet downgradient of the injection

well barrier wall within 3 months following emplacement of the cylinders and remained in many of the pilot test wells through the 9 month sampling duration of the study. Based on this data and the 1,1-DCE data collected throughout the duration of the pilot test, it appears that the sustained release oxidant cylinders are capable of reducing and maintaining a reduction in 1,1-DCE concentration at a distance of up to 30 feet from the injection well barrier wall. The emplaced cylinders resulted in a sustained decrease in 1,1-DCE concentration throughout the pilot test area for a period of up to 9 months after cylinder emplacement This case study will highlight design, installation, and results of the pilot study.

Monitoring Flow in Unsaturated Soils Using Geophysical Sensing Techniques

Hundley, Britton, [email protected], and Stephen Moysey, Clemson University, Clemson, SC

Infiltration processes in unsaturated soils can prove difficult to characterize and may have significant impacts in terms of contaminant transport. Electrical resistivity (ER) geophysical methods are sensitive to water content changes within a soil matrix and may be used in conjunction with traditional sensing methods to better monitor and characterize flow. Lysimeter columns fitted

with load cell mass balance systems, moisture and matric potential probes as well as multiple ER arrays are used as a platform to monitor flow behavior under various conditions and determine associated sensor responses. In situ field measurements can provide this type of data to help make more informed decisions when simulating aspects of flow in transport problems.

Influence of Methane Inhibitors and High Molecular Mass Electron Donors on Chlorinated Solvent Biodegradation

Ivey, Morgan, [email protected], and Kevin Finneran, Clemson University, Clemson, SC

Chlorinated solvent bioremediation encompasses a number of combined microbial and chemical reactions that oxidize or reduce the contaminant(s) of concern. In the case of trichloroethylene (TCE), many approaches rely on adding electron donors to stimulate chlororespiration, in which cells gain energy to grow by sequentially reducing TCE to ethene.

In recent years, the idea that TCE could be

reduced by inhibiting methane production to stimulate dechlorination has been put into practice by vendors. The theory is that if methane production is inhibited, electrons will be redirected to chlorinated solvent reduction for complete dechlorination. However, if methanogenesis is inhibited, then microbial activity that is key in reducing chlorinated solvents may, or may not, occur. Additionally, adding carbon substrates to

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the subsurface rarely targets a single microbial population, and several microbial groups respond to electron donor amendment.

The purpose of this research is to evaluate the influence of methane inhibitors on chlorinated solvents by using electron donors in various concentrations. Electron donors include plant-based essential oils, lactate, and statins. The work will demonstrate that inhibiting methanogenesis alone may not expedite dechlorination, and the broader impacts on the microbial community that are central to reducing TCE are larger than this single reaction. It is anticipated that using electron donors at near stoichiometric concentrations will help control methanogenesis while facilitating complete dechlorination.

Data suggest that experiments containing high molecular mass electron donors may be more effective when paired with a methane

inhibitor than when applied alone, specifically for lactate and emulsified vegetable oils. However, the addition of some amendments intended to be methane inhibitors may be ineffective at controlling methane production, and in some cases methanogenesis increased due to the other materials present with statins (e.g. yeast). One statin used appears to not be inhibiting methane production at all, but two plant-based essential oils could be effective at controlling methanogenesis during dechlorination. Although the vendors market these with added electron donors, each of the materials acts as an electron donor on its own. The statin may be less effective because of a misreported statin content in the red yeast rice carrier. Future analysis will determine whether the product contains a high enough percentage of statin compounds to be effective at controlling methanogenesis.

Large-Scale Remediation of TCE Using Abiotic Degradation with ZVI and Enhanced Biological Degradation

Kelley, Robert, [email protected], Cascade Technical Services

As part of an environmental remediation effort at the McConnell Air Force Base in Wichita, KS, a pneumatic emplacement technology (Ferox™) has been used for in-situ ZVI injections on six sites. Treatment was applied to chlorinated solvent contaminated soils and groundwater. At some sites, there has been an increase in daughter products including vinyl chloride and high levels of methane. However, the contribution of biological activities and the role of the levels of carbon (electron donor) to these increases was not clear.

Over 3,500 tons of ZVI was injected during four campaigns between 2014 and 2017. All the sites treated with ZVI saw a greater than 100 mV decrease in ORP as reductive conditions were established. The pH slightly increased and methane, ethane and ethene concentrations increased. On average at most sites, the TCE concentrations were below USEPA MCL and KDHE Risk levels within a couple of months. The

Ferox™ patent is based on the results that less iron distributed better through the formation give a better result. Pneumatic emplacement of in-situ amendments increased contact and permeability within the contaminated zones in order to achieve treatment goals within a short period of time. Experience has also shown that too much carbon in the system can lead to methanogenic conditions and less reductive dechlorination. A variety of products and techniques have been used to determine the optimum balance of ZVI and carbon to produce degradation of the TCE at several sites on base. In some areas, more ZVI was injected, and in other area a molasses-base product or a nutrient blend product was added. A wide range of biogeochemical conditions were detected throughout the base. Each of these conditions required a different approach. The results of these different approaches and how each approach was selected will be presented.

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Application of a PFAS Mobile Laboratory Enables Dynamic Work Strategies at PFAS Site

Kelley, Robert, [email protected], Michael Rossi, Helmer Korb, and Seth Pitkin, Cascade Technical Services, Montpelier, VT; and Joseph Quinnan, Arcadis, Novi, MI

Direct screening tools do not work for PFAS for a variety of reasons and although there are several field chemistry techniques evolving, none of these methods have the sensitivity nor selectivity to adequately satisfy the objectives of PFAS site investigations. The known complexities related to the fate and transport of PFAS, coupled with their persistence and toxicity at low levels, present a need for rapid, dynamic, high resolution site characterization (HRSC) approaches which can cost effectively define the nature and scope of the required remedies. In order to achieve a rapid, single mobilization investigation of a PFAS site, the authors deployed a mobile LC/MS/MS laboratory to analyze site specific PFAS compounds in groundwater at single digit part per trillion (ppt) levels.

The subject investigation was focused on determining the horizontal extend of PFAS groundwater contamination. Prior to this investigation, there was limited PFAS information and the distribution of PFAS was poorly understood. The majority of PFAS concentrations in monitoring wells were all below 1000 ppt. The primary PFAS present was perfluorooctanesulfonic acid (PFOS); the required detection limit for the onsite lab was set to 12 ppt based on Michigan DEQ’s GW standard PFOS. In order to assess the PFAS levels and distribution, a dynamic sampling strategy involving two groundwater sampling teams was used to

maximize the cost effectiveness of the onsite lab and minimize the duration of the investigation. The onsite laboratory used an accelerated solid phase extraction sample prep technique followed by LC/MS/MS analyses that are based on EPA Method 537.

Over the course of two and one half days 31 groundwater samples were collected and analyzed by the onsite LC/MS/MS laboratory. Additional QC samples were collected to ensure no cross contamination (derived from drilling fluids and sampling materials) occurred during the drilling and sampling activities. Analytical results were typically reported within four hours of sample receipt with additional analyses run on the autosampler overnight to cover dilutions; on average, 33 analytical runs (includes QC) per day were needed to cover the concentrations observed in these samples. Concentrations of PFAS compounds ranged between non-detect (@ 5 ppt) values and 7,000 ppt. Although several challenges were encountered during this investigation, the laboratory was able to meet all of the site’s data quality objectives and provide defensible, cost effective analytical data that facilitated the adaptive sampling strategy used for this investigation. Additional information on method optimization and lessons learned will be discussed as part of this presentation.

Daily Field Updates of 3D Visualization to Optimize Source Area Delineation

Kenwell, Amy, [email protected], Jeffrey Ahrens, and Raphael Siebenmann, Geosyntec Consultants, Charlotte, NC

Through a combination of 3D visualization and rapid turnaround of laboratory results, Geosyntec was able to develop and update a contaminant visualization to optimize the delineation of source area soil impacts during subsurface field investigations. This presentation will discuss

a workflow that combines daily data updates with 3-dimensional visualization through Earth Volumetric Studio (EVS) software to rapidly update the contaminant visualization and optimize field decisions.

This workflow was applied during a source-

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focused remedial investigation at a former manufacturing facility in North Carolina. The goal of the investigation was to characterize and delineate dense non-aqueous phase liquids (DNAPL), particularly tetrachloroethene (PCE), to develop a design for in-situ thermal remediation (ISTR). During contaminant source characterization, direct-push drilling methods (DPT) are often used to delineate contaminant extents in soil. A key field tool in these investigations is the photo-ionization detector (PID) which estimates the concentrations of volatile organic compounds (VOCs) using ultraviolet (UV) light. PID results often drive decisions on where to collect samples and where to drill the next investigative borehole. Unfortunately, PIDs are not always effective and can lead to lost time, resources, or even an insufficiently characterized source. The workflow used in this investigation allowed for analytical verification of PCE concentrations to achieve a more complete delineation of the contaminant mass.

During this investigation, soil samples were shipped daily to a laboratory under one-day turnaround time. The field team worked with the lab to develop a custom electronic data deliverable

(EDD) to rapidly update the EVS model daily, from the field. By using the previous day’s results to redefine the source zone extent and see the data presented in three dimensions on a map, the field crew was able to more effectively choose borehole locations and sample depths. In addition, EVS has a built-in Drillguide tool which calculates model uncertainty and proposes borehole locations that will maximize statistical reduction of uncertainty. Drillguide can be used in conjunction with the conceptual site model (CSM) to efficiently reduce uncertainty.

At the test site, data from a preliminary DPT and Membrane Interface Probe (MIP) investigation were used to develop the initial visualization. During the ten-day field investigation, 35 DPT borings were advanced and 160 soil samples were added to the dataset. Another 12 borings and 42 samples were collected during a second field investigation to further refine the source. The EVS visualization helped staff identify data gaps and collect the information needed to minimize uncertainty and calculate an accurate treatment volume for remedial design during the limited timeframe available for these investigations.

Radionuclide Waste Disposal: Impact of Plants on Flow, Transport, and Potential Uptake of Uranyl-Phosphate in the Vadose Zone

Kerschner, Daniel, [email protected], Haley Willis, Tim DeVol, Stephen Moysey, Brian Powell, and Christophe Darnault, Clemson University, Clemson, SC

Radionuclide contaminants are common in the environment and the effects of plants on the fate and transport of these contaminants has not been well studied. This research aims to determine the flow and infiltration of water in the vadose zone and understand the fate and transport of uranium with interaction of plant roots and their exudates in a water stressed environments. Benchtop experiments using three 2D tanks, uniformly

packed with ASTM sand, were performed. Uranyl-phosphate, doped with U235, were placed in the tank. The plants in question of species A. virginicus were planted at the surface of two tanks, allowing their roots to spread to the radionuclide source. One tank containing A. virginicus was water stressed while the other was not. The 2D tank light transmission method was created using a flow-through tank with transparent faces. A LED light

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and CMOS DSLR Nikon D5500 camera were used to photograph the flow patterns. The photographs were converted from RGB into HVI and analyzed in Matlab to quantify the flow patterns and water saturation distribution. Radionuclide transport was monitored using an automated gamma scanner

and NI LabVIEW 2015. Effluent was captured and analyzed using an ICPMS. Data generated will provide information on the fate and transport of uranium, the preferential flow phenomena, and the infiltration process in plant-water-sand porous media systems.

Utilizing Bioavailable Absorbent Media (BAM) to Remediate GRO, DRO, Crude Oil, and PVOC in Groundwater

Kinsman, Larry, [email protected], ORIN Technologies, Verona, WI

Bioavailable Absorbent Media (BAM) is a sustainable, pyrolyzed, cellulosic bio-mass product (>80% fixed carbon) derived from a proprietary blend of recycled organic materials with a high cation exchange and an estimated half-life of 500 years. BAM has diverse pore sizes with a minimum total surface area of up to 1,133 square meters per gram or 127 acres/lb. Most importantly, BAM’s affinity for organic and inorganic compounds supports maximum contact (bio-availability through high sorbency) with microbes allowing for complete degradation.

ORIN successfully conducted a pilot test near Jackson, MS to treat groundwater contaminated with GRO, DRO, Crude Oil, and PVOC utilizing BAM and a nutrient blend. Three separate pilot areas were conducted with different treatment chemistries: BAM alone, BAM mixed with nutrients, and nutrients alone. DPT points were advanced around a targeted well in each area. The treatment chemistry was mixed with water and injected through DPT points utilizing a side injection rod. During injection activities,

a vacuum truck extracted groundwater from various wells within and adjacent to the injection areas. The vacuum truck removed contaminated groundwater and controlled the hydraulic gradient during injection activities at impacted monitoring wells and extraction wells.

Within two weeks following injection activities, groundwater sampling showed non-detect contaminant levels in the BAM with nutrients and BAM alone areas. The petroleum hydrocarbons (PHC) remained at non-detect levels for the duration of the 12-week pilot test for the BAM alone area whereas benzene showed a slight rebound in groundwater at the BAM with nutrients area. Microbial analysis also showed a significant increase of biological growth in both the BAM alone and BAM with nutrients compared to nutrients only. The nutrient only area had limited reductions of DRO, GRO, and Crude Oil. BAM is considered to be the best treatment option due to its honeycomb structure providing high absorption capacity, absorbing the PHC and promoting microbial growth.

Utilizing Bioavailable Absorbent Media (BAM) to Remediate Chlorinated Hydrocarbons in Groundwater

Kinsman, Larry, [email protected], ORIN Technologies, Verona, WI

Bioavailable Absorbent Media (BAM) is a sustainable, pyrolyzed, cellulosic bio-mass product (>80% fixed carbon) derived from a proprietary blend of recycled organic materials with a high

cation exchange and an estimated half-life of 500 years. BAM has diverse pore sizes with a minimum total surface area of up to 1,133 square meters per gram or 127 acres/lb. Most importantly,

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BAM’s affinity for organic and inorganic compounds supports maximum contact (bio-availability through high sorbency) with microbes allowing for complete degradation.

ORIN successfully conducted two pilot tests near Moultrie, GA to treat groundwater contaminated with chlorinated solvents (CS) using BAM, a pyrolized cellulosic material. BAM was mixed with water and injected through 4 and 6 DPT points encompassing MW-03 and MW-04 respectively. A total of 700 and 1,200 gallons of BAM solution was injected through the 4 and 6 points respectively. During injection activities, BAM was observed in both MW-03 and MW-04. Treatment extended from 10 feet below ground surface (ft bgs) to approximately 30 ft bgs and from 20 ft bgs to 30 ft

bgs around MW-03 and MW-04 respectively.

Baseline samples were taken prior to treatment to characterize the contaminant level and compare treatment reductions. Contaminant baseline levels for PCE were 4,590 ug/L and 22,500 ug/L at MW-03 and MW-04 respectively. Treatment around MW-03 has yielded non-detect results for over 1 calendar year and multiple sampling events. While treatment around MW-04 produced non-detect results for all COC’s sampled in just 1 week after treatment. The results yield a 100% reduction for contaminant levels at MW-03 and MW-04. BAM is considered to be the best treatment option due to its honeycomb structure providing high absorption capacity, absorbing the CS and promoting microbial growth.

Vapor Intrusion Mitigation Technologies & Trends

Kleine, Jordan, [email protected], Land Science, Atlanta, GA

With the constant advancements and evolution relating to contaminant vapor intrusion (VI) regulatory guidance and responses to these guidances, the need to better protect overlying structures from sub-slab VOC vapor migration with innovative, affordable technologies continues to be at the forefront of VI discussions across the nation. As VI guidance(s) continue to evolve and more is learned about the threat of the VI pathway, the number of impacted brownfield sites requiring VI mitigation continues to expand. Several successful VI mitigation projects have been completed throughout the Southeast US for both new construction and existing (Retro-Fit) buildings from local corner convenience stores to larger manufacturing/warehouse facilities.

Recent advancements have been made with VI barriers to address this growing need. Previously available VI barrier technologies were and continue to be plagued with challenges concerning installation, integrity and poor chemical resistance characteristics. Composite barrier technologies have been developed to address the chemical resistance and installation limitations the previous vapor barriers offered in the industry. Composite

barrier systems, particularly those which utilize the chemical resistance features of high density polyethylene (HDPE) and the constructability benefits of a spray applied asphalt latex to offer multiple layers of protection and redundancy, are a cost-effective solution for mitigating newly constructed buildings from VOC vapors specific to VI and building construction.

Existing structures present very different challenges to VI mitigation. The same mitigation techniques used to mitigate VI in new buildings, or small residential structures, are not likely to be cost effective or applicable when mitigating larger structures. A VI coating technology has been developed to mitigate VI into existing structures which provides a durable/wearing surface for industrial use and vehicular traffic, while offering flexibility with a variety of aesthetically pleasing finishes. Coating the existing concrete slab without the necessity of an additional concrete overlay provides environmental consultants and building owners greater flexibility when selecting a mitigation system for an existing structure. Additionally, greater assurance can be given to building owners that the VI concern has been

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properly mitigated; in some cases, without the need to maintain mechanical sub-slab depressurization

systems, which often requires long term operations and maintenance.

Overview of State LNAPL Management Strategies

Laub, Matthew, [email protected], AECOM, Warrenville, IL, and Matthew Zenker, AECOM, Morrisville, NC

Closure of sites impacted with non-aqueous phase liquid (NAPL), particularly petroleum hydrocarbon impacts, has traditionally required the removal of free product to the “…maximum extent practicable (MEP) as determined by the implementing agency…”, as defined in the Code of Federal Regulations. States have historically taken a varied interpretation of MEP, often implementing inconsistent or unclear policies which rely on questionable metrics such as measured NAPL thickness or the presence of a sheen. Policies such as these result in stakeholders attempting to remove NAPL via physical recovery, which is resource-intensive and oftentimes not effective. As a result, low-risk NAPL sites remain open after many years and can drain stakeholder and/or trust fund program resources.

A NAPL science renaissance is underway, beginning in the late 2000s, with the publication of Interstate Technical Regulatory Council (ITRC) and ASTM guidance on developing NAPL conceptual site models and utilizing a

risk-based approach to evaluating NAPL sites. The environmental agencies of many states have taken notice. States across the country have begun to accept risk-based evaluations of NAPL sites, develop guidance, promulgate rules, develop risk based remedial approaches and, in some cases, close sites with NAPL in-place. The use of conceptual site models (CSMs), which evaluate NAPL behavior and its impact on the environment, have changed the way MEP is interpreted. The use of risk-based approaches to evaluate low-risk sites results in closure of otherwise idle sites, which benefits all parties: regulators, site-owners and stakeholders.

This presentation will review the challenges of closing NAPL sites using traditional concepts of MEP, why NAPL removal isn’t as effective as once thought, review how states are adapting to new NAPL science, and provide case studies of successful closure of NAPL sites using risk-based evaluations.

Real Life Data Demonstrating the Success of Bacillus in the Bioremediation of Petroleum Contamination in Soil and Groundwater

Lawson, III, Joseph, [email protected], and Jeffrey Ballsieper, Progress Environmental, Winston-Salem, NC; Chris Penet, Bio-Cat Microbials, Troy, VA; and Jessica Spears, Bio-Cat Microbials, Shakopee, MN

According to the United States Environmental Protection Agency (USEPA), 10-25 million gallons of oil are spilled annually. While petroleum consumption is an essential component of the global economy, petroleum spills often create problematic soil and groundwater contamination

that requires expensive remedial activities, pollutes drinking water, negatively impacts property values, impedes development, and can be toxic to ecosystems. Even years after a petroleum spill or leak, petroleum hydrocarbons often remain, rendering the contaminated land unusable

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and contaminated groundwater dangerous for consumption.

Although research into the accelerated degradation of petroleum-related compounds by microbes (bioremediation) has been ongoing, field conditions are often difficult to replicate. Bioremediation efforts usually involve biostimulation (the use of nutrients to stimulate existing microbial populations) or bioaugmentation (the introduction of microbes known to possess oil-degrading properties). In addition, research into genetically engineered microbes (GEMs) continues, although concerns remain regarding potential adverse environmental effects. Because of their metabolic diversity and ability to utilize various materials as “food,” naturally occurring, Bacillus-based microbes are great candidates for the bioremediation of petroleum hydrocarbons.

Progress Environmental (Progress) has collaborated with BIO-CAT Microbials to develop a unique, multi-strain blend of Bacillus and Brevibacillus designed to tackle the remediation of petroleum hydrocarbons. It is important to note that the microbes work synergistically, and no single species can successfully degrade all of the complex components associated with petroleum hydrocarbons. Field trials have included a variety of petroleum spill/release scenarios involving various petroleum products including gasoline, heating oil, and mineral oil. Progress passively injected the bacterial blend (Enviro-BAC) into a contaminated groundwater monitoring well at an active gasoline station. The gasoline station had previously experienced a release from an underground storage tank (UST). After 60 days following the initial Enviro-BAC injection, analysis

of groundwater from the treated monitoring well indicated dramatic reductions in volatile organic compounds.

It is not unusual for this level of contaminant reduction to require years of traditional treatment methods (e.g., vacuum extraction, air sparge, etc.). The groundwater samples were also analyzed to determine total microbes present. The microbial population increased from 130 (prior to treatment with Enviro-BAC) to as high as 61,000,000 CFU/mL, confirming microbial survival and proliferation. Similar results have been documented on soil contaminated with heating oil. Contaminated soil treated with Enviro-BAC exhibited a 72% decrease from the initial concentration of total petroleum hydrocarbons as diesel (TPH-D) approximately 12 weeks following application of the product. Enviro-BAC application to a surface spill of mineral oil (approximately 300 gallons) displayed similar results. Soil samples generally exhibited an average decrease of approximately 76% in TPH-D concentrations within 12 weeks of soil treatment. Notably, soil samples collected in the immediate source area of the release (primary treatment area) exhibited an 87% reduction in the TPH-D concentration. Enviro-BAC field trials are ongoing, but data clearly support significant petroleum degradation (effective on multiple petroleum products) in various environments. The benefits of utilizing Enviro-BAC include: minimal disturbance to a property or facility and its operations; decreases remedial duration and expedites regulatory closure; provides an efficient and cost effective remedial alternative to traditional methods; is landfill conscious; is effective on soil and groundwater; and, is environmentally responsible.

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Treatment Technologies for Separation and Destruction of Per- and Poly-Fluorinated Substances (PFAS) in Soil and Water

Liang, Shangtao, [email protected], and Dora Chiang, AECOM Environment, Atlanta, GA

Per- and polyfluroalkyl substances (PFAS) are a complex family of emerging contaminants made of more than 3,000 manmade fluorinated organic chemicals that have been produced since the 1940s. Due to their strong C-F bonds PFAS were widely applied in surfactants, packaging materials, personal care products, and fire retardants for decades until their harmful effects were reported. Some PFAS were found to be bioaccumulative and likely carcinogenic, and unfortunately they are extremely recalcitrant, resistant to natural degradation, and invulnerable to traditional destructive technologies.

Although perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are under the most intense study in terms of toxicity, fate and transport, and treatment technologies, other species of PFAS, especially short-chain PFAS (C4-C7) can’t be excluded from consideration. Short-chain PFAS, PFOA, and PFOS often co-occur in aqueous film forming foam (AFFF)-impacted wastewater. Even for industrial wastewater, short-chain PFAS may still present in the treated water through chemical or biological transformation of PFOA, PFOS, and PFAS precursors. Developing a treatment technology for a wide range of PFAS compounds can be challenging. The chemical properties of those compounds are related to their structures in terms of carbon chain length, branched versus linear, and functional groups.

In general, shorter chains are more mobile and less bioaccumulative but not necessarily more amenable to treatment. A great deal of data has been collected about the treatability of PFOA and PFOS but information focused on short-chain PFAS is still scarce.

Despite innovations in technology development, only a few mature PFAS remedial technologies can be scaled up for field applications. Sorption technology is most widely used and is readily scalable to field demonstrations. However, the disposal of spent adsorbents is problematic. It requires frequent change-outs especially when the influent is high in PFAS concentrations or impacted by short-chain compounds. As for destructive technologies, only a few of them are proven effective or partially effective for PFAS due to their unique chemical and physical properties. Among those technologies, most of them are still at bench-scale demonstration and are primarily focused on PFOA and PFOS. Before the technology can be actually applied in the field, it needs to go through a treatability demonstration, optimization of treatment conditions, field efficiency validation, and commercial development.

This presentation will summarize the available PFAS remedial technologies for both water and soil treatments and provide information about demonstration results, state of development, and advantages as well as limitations.

Case Study: Site Characterization of CVOCs Using PSG Samplers

Malin, Shaun, [email protected], HRP Associates, Inc., Greenville, SC

You and your team are locked in a conference room trying to decipher the answer to the question, “What’s up with the data from the southwest?” With a sigh, you realize that after 20 years of routine groundwater monitoring by your

firm and a predecessor, the conceptual site model is still evolving due to the installation of one cross-gradient groundwater monitoring well. This case study summarizes the selection, employment, and evaluation of a passive soil gas (PSG) survey used

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to investigate 10 acres of previously unassessed on-site, down-gradient property at a former manufacturing facility. The PSG survey was performed in phases during the implementation of a voluntary Remedial Investigation (RI) designed in accordance with the NCDEQ REC Program statutes.

Transactional-based due diligence investigations in the 1990’s identified two principle areas of concern related to former degreasing operations. Minimal site characterization followed by the installation of a robust dual-phase extraction system reduced contaminant concentrations by orders of magnitude in those source areas. Client imposed financial constraints following system shut-down in the early 2000’s lead to a final remedy selection of monitored natural attenuation (MNA) and the implementation of long term groundwater monitoring.

Company acquisition in 2010, new client contacts with a low tolerance for risk, and the continued evolution of North Carolina regulatory statutes provided the impetus for a mandate to expedite site closure. The inherent problem with delaying the completion of the RI two decades is that regulations change, action levels drop, and new topics surface (i.e., vapor intrusion). In short, the Site wasn’t delineated in accordance with REC Program requirements (wells that yield data below standards at the plume periphery). HRP evaluated several field screening technologies and determined that the employment of a PSG survey was an effective and cost efficient method to 1) determine optimum locations for delineation (“clean”) monitoring wells across a large area, and 2) preliminarily evaluate the potential for vapor intrusion into on-site structures. PSG surveys

utilize adsorbent samplers that are emplaced subsurface to adsorb chlorinated volatile organic compounds (CVOCs) in soil gas. HRP utilized PSGs provided by BEACON Environmental Services, Inc. (BEACON). Samples were analyzed by BEACON using gas chromatography/mass spectrometry (GC/MS) instrumentation, following modified EPA Method 8260C procedures in accordance with the reporting requirements of ISO 17025. A total of 110 PSG samplers were installed throughout the unassessed acreage in two phases.

Data resulting from the first phase of PSG samplers was predictable in certain areas of the Site, and unexpected in others. Specifically, an area was identified in the undeveloped portion of the property to the southwest. A comprehensive review of site history provided no insight as to the explanation of the data. The project manager deemed the results as anomalous, and requested the installation of a well within the center of the area to rebut the soil gas data. Groundwater data obtained from this location yielded the highest CVOC concentrations at the Site. A subsequent phase of PSG assessment followed by monitoring well installation confirmed a new area of concern at the Site which modified the CSM prior to finalizing the Remedial Action Plan. Discovery of this AOC increased the short term cost of the project; however, the long term impacts (cost and project longevity) have likely been significantly reduced. Employing the PSG survey during the RI phase of the project enabled HRP to evaluate unassessed acreage in a cost effective and efficient manner, and most importantly, identify a source area that likely would have not been discovered for another decade.

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Visualizing Subsurface Flow Mechanisms Using 4D X-Ray Computed Tomography Imaging Within a Heterogeneous Porous Media

Mamun, Abdullah Al, [email protected], Stephen Moysey, and Mine Dogan, Clemson University, Clemson, SC

Time lapse X-ray Computed Tomography (CT) scans provide a non-invasive and non-destructive way to examine the fate and transport phenomena in a heterogeneous material in 4D (i.e. transient three-dimensional). An infiltration experiment was performed on a dry cracked soil column by continuously injecting a non-reactive tracer NaI from top and was scanned throughout in high resolution MILABS MicroCT at 7 minute interval to visualize the flow pattern and mechanisms associated within both macropore and matrix domain. Time lapse water content images were produced by image reconstruction and processing

of the dry and wet CT scans. At low flow rate, the flow was dominant through macropore as film flow with comparatively low imbibition from macropore to matrix and at an increased flow rate, the macropores became completely filled with a higher imbibition rate. In addition, some basic macropore flow mechanisms (i.e. attaining threshold air entry pressure to activate macropore flow) were also observed. The outcome of this study validate the capability of high resolution 4D CT images in characterizing non-uniform macropore-matrix flow interactions in subsurface.

Treatment of Coal Tar Using In Situ Smoldering Combustion

McMaster, Michaye, [email protected], Marlaina Auger, and Luana Jo, Geosyntec Consultants, Guelph, Ontario; David Liefl and Andrew Sims, Savron Solutions, Guelph, Ontario; and Tyson Campbell, DuPont Corporate Remediation, Fort Mill, SC

In situ smoldering using self-sustaining treatment for active remediation (STAR) is being applied as the primary source remedy at a site located in Newark, NJ. The STAR technology relies on the contaminant to be the fuel source and with supplied air ignition is initiated. Once ignited the burn is propagated with the supplied air only and not more heat. The process can be sustained below the water table. Site contaminants include coal tars and cresols in both fill and native geological materials. The remedial objectives include treatment of free product to the extent practicable. Site activities have been on-going for more than 3 years with about one year of operations remaining.

Treatment cells which are comprised of ignition points and vapor extraction wells are installed using conventional direct push technology. Interstitial thermocouples are installed to assess operational performance and vapor extraction

wells are installed to extract injected air and capture vapors. Extracted vapors are treated using conventional ex-situ means (thermal oxidizer). Cell cycle times are relatively short (days). Once a cell is complete post-remedy verification is conducted.

This presentation will focus on one lagoon area that has been investigated, treated and remedy verification completed. This area is approximately 2 acres in size and represents what other candidate sites may encounter. More than 120 ignition points were installed in first and then treatment proceeded. The period of performance was approximately 6 months. Remedy verification uses a multiple lines of evidence approach. After the first round of treatment about 20% of the lagoon area required re-work and additional smoldering treated the remaining coal tar. Information on the STAR process in this lagoon will be presented.

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Design and Implementation of an Arsenic Phytoremediation Pilot Study at a Wood Treatment/Chromated Copper Arsenate Site

Moore, Alan,[email protected], Nutter & Associates, Inc., Sylva, NC; David Huff, Nutter & Associates, Inc., Athens, GA; Caleb Krouse and Barry Harding, AECOM, Morrisville, NC; and Steven Aufdenkampe and Scott Pittenger, Norfolk Southern Corporation, Atlanta, GA

Historical use of Chromated Copper Arsenate (CCA) as a wood preservative for lumber treatment occurred in the United States from the mid-1930’s to 2003, when producers voluntarily ceased using CCA for residential wood products. Legacy CCA sites are regulated due primarily to the presence of elevated soil arsenic (As). The former Columbia Wood Preserving (CWP) site, located in Columbia, South Carolina, previously occupied approximately nine acres of wood treatment operations on land now owned by Norfolk Southern Railway Company. Sustained As concentrations in the site soils range between 100 to 1,000 milligrams per kilogram (mg/kg).

Norfolk Southern Railway Company elected to conduct a phytoremediation pilot study as a cooperative remedy in portions of the site. The objective of the pilot study is to evaluate phytoremediation as a potential cost effective and sustainable means to supplement soil excavation and disposal efforts.

The field pilot study was initiated in May 2017 in an area historically used for staging and drying treated wood products at the CWP site. A randomized block design was used to test four plants, distributed randomly in individual plots, within six replicate rows or blocks (24 plots total). Test plant species included Pteris vittata Edenfern™ (ladder brake fern), Equisetum hyemale (rough horsetail), Amaranthus gangeticus (carnival amaranth), and a native grass/forb control mix. Rough horsetail and carnival amaranth are both relatively novel plant species for use in As phytoremediation studies. Initial field x-ray fluorescence readings of soil As concentrations within the study area ranged from approximately 25 to 300 mg/kg. Innovative field methodologies were employed to manually till and homogenize study area soils such that As concentrations, along

with other soil variables, were as similar as possible across all plots. Twenty-four 3 x 3 foot plots were constructed using homogenized study area soils. Based on agronomic analysis of the homogenized soils, key soil amendments were applied, and each plot was then sampled for baseline As concentrations in the upper 12 inches of soil. Laboratory-analyzed As soil concentrations ranged between 76.4 to 104.7 mg/kg, with a mean of 86.6 mg/kg across all 24 plots.

A non-destructive mid-season harvest was conducted in August 2017 on a third of the plants in each plot to assess early-growth plant tissue As concentrations, mid-season soil As concentrations, and mid-season biomass production. A final harvest was conducted in October 2017 to assess overall plant tissue As concentrations, soil As concentrations, overall biomass production, and regeneration efficiency of previously harvested portions of the plots.

Arsenic concentrations in EdenfernTM aboveground plant tissue were significantly higher than all other treatments by many orders of magnitude. The overall average EdenfernTM bioconcentration factor (BCF) achieved in this single season study was 32, which is higher than many other multi harvest studies, including multi-year studies that showed a significant reduction in soil arsenic concentrations. Slightly alkaline soils at the site may have contributed to high arsenic uptake in EdenfernsTM.

Arsenic uptake by the horsetails and amaranth was not significantly different than the native grass and forb mix, with average BCFs between 0.07 and 0.2. The results of this investigation are contrary to one study that suggested A. gangeticus is a hyperaccumulator of arsenic, as well as studies that suggest E. hyemale is capable of achieving BCFs

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between 0.8 and 4. A significant percentage of the amaranth plants did not survive by the mid-season harvest, and the majority of them were dead by September. This may have been due to poor

seed quality or soil conditions not favorable to amaranth. The horsetails and native grass and forb mix grew well.

Implementing Sustainable Remediation via Biostimulation to Expedite Site Closure of a Large Dissolved TCE Plume in Northern Georgia

Morris, Kevin, [email protected], ERM, Wilmington, DE

A full-scale bioremediation approach via stimulation of the indigenous microbes to achieve anaerobic reductive dechlorination was developed and implemented to remediate trichloroethene (TCE)-impacted ground water at an industrial facility in Northern Georgia. This low-energy sustainable strategy replaced an ineffective and energy intensive electro-chemical remedy that had been operational for over 5 years. The full-scale biostimulation design included both source area treatment to address elevated residual TCE concentrations and a permeable injection biobarrier to mitigate additional migration of dissolved phase TCE offsite.

A total of 70 injection wells were installed in December of 2008 and insoluble substrate (emulsified vegetable oil) injections were conducted in January and February of 2009. Thirty-five injection points were installed at a spacing of 15 feet in the TCE source area, which covers an approximate area of 150 by 120 feet. The injection points were installed to the top of bedrock between 20 and 50 ft below ground surface (ft bgs) in a saprolite overburden. A total of 35 injection points were also installed at a spacing of 15 feet over a linear distance of approximately 500 feet down water table gradient of the main TCE source area to generate the permeable injection biobarrier. The emulsified vegetable oil solution (NewmanZone) was injected into each point at a flow rate of approximately 2 to 4 gallons per minute (gpm) at a pressure of less than 30 pounds per square inch gauge (psig). This low flow and pressure helped to minimize potential short-circuiting to the surface that is common

during substrate injection programs. The total combined injection volume for all 70 injection points was 98,000 gallons of solution comprised of 95,000 gallons of water and 3,000 gallons of the substrate. Ground water pumped from a bedrock well was used to provide the mixing and flushing water together with hydrant water, as ground water is the best source of water that is compatible with the indigenous anaerobic microorganisms.

Analysis of ground water in the source area continues to show the lowest TCE concentrations since sampling began in 1993 (from an average concentration of 6 mg/L to < 5 Âµg/L). Innocuous reductive dechlorination end products ethene and ethane were also detected at concentrations as high as 120 ppb in three of the source area wells. This is a significant increase over the <1 ppb detected prior to implementing the full-scale biostimulation program. Monitoring wells downgradient of the injection barrier also continue to show a decreasing trend 4 years after completion of the substrate injections. Data from two of the downgradient wells also indicate the lowest TCE concentrations ever detected at those locations, including detections of ethene and ethane, an indication that the biobarrier continues to remain effective more than two years after the initial biostimulation. Trend analysis of data from the site monitoring wells indicates that natural attenuation can be proposed as the final remedy for an additional 2-year period that is anticipated to lead to site closure approximately 15 years ahead of the original closure estimates.

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Chemical Reduction and Stabilization via Shallow Soil Mixing to Treat CrVI and Lead in Soil in Barranquilla, Colombia

Morris, Kevin, [email protected], Environmental Resources Management, Wilmington, DE; James Henderson, DuPont, Charlotte, NC; Constanza Hernandez, and Diego Sanchez, ERM, Bogota, Colombia; and Paulo Barreto, CH2M, Philadelphia, PA

A former bronze smelting plant (Site) located in the city of Barranquilla, Colombia operated from the early 1960’s to 2000. The plant is approximately 7,760 square meters (m2) with approximately 3,800 m2 of metals impacted soil where slag and sediment had been previously deposited during Site operations. Site investigations conducted from 2010 to 2012 found elevated concentrations of hexavalent chromium (CrVI) and lead in soil above screening levels down to approximately 1 m below ground surface (bgs). Maximum concentrations detected were 229 and 9,220 mg/kg, respectively. The Site is bordered by other industrial manufacturing facilities to the north, residential housing to the east and an elementary school immediately adjacent to the western edge of the property. The Magdalena River, one of the main water courses in Colombia, is located approximately 700 m to the northeast. After reviewing several remedial strategies and engaging all stakeholders a strategy was developed that allowed for the beneficial reuse of the property with minimal impact to the adjacent residents and the elementary school.

Based on the data collected during the bench study completed in May 2016, a full-scale shallow soil treatment was designed to chemically reduce the CrVI to CrIII and stabilize the lead in the impacted area. The chemical reduction and stabilization soil treatment included a mixture of 3% Portland cement and a stoichiometric ratio of 6:1 calcium polysulfide (CPS) to Cr VI in soil. Soil surrounding the perimeter of the treatment area was mixed using 1m x 1m cells, in order to preserve the integrity of a

surrounding boundary wall. Prior to implementing the full-scale mixing, a smaller scale “bucket test” was conducted to develop and optimize the mixing protocols and sequencing and was an adjustment from the original work plan. The soil mixing was conducted using a CAT 750 excavator. Approximately, 3,800m3 of soil were mixed and treated January and February 2017. Following the treatment of soil, 71 composite samples were collected in order to assess remediation effectiveness. Cr VI and lead were analyzed in soil and in the leachate of a SPLP test. An average of 26 days passed between the collection the samples and laboratory analysis. The reduced and stabilized soil was then compacted, graded and capped with 15 cm of subbase and 15cm asphalt cap.

The complete mixing of soil and cement was achieved as the average pH of the collected samples was greater than 11. Average detected concentration of Cr VI was 4 mg/kg, a reduction of 96%. Average SPLP for Cr VI was 0.06 mg/L. Average detected concentration of lead was 1,245 mg/kg. No significant concentrations of lead were detected in the SPLP analysis. The potential for future exposure and infiltration to groundwater was also mitigated through the installation of the 30cm cap. The elevated pH catalyzes the reduction reaction of Cr VI that allowed the reaction to continue after the sampling event as the chemical reduction process typically continues for at least 90 days. The sustainable remedial strategy allowed for beneficial reuse of the property, with no impact to the surrounding community.

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Design Verification Program - Lessons Learned from Pre-Application Assessments at In Situ Remediation Sites

Northington, Chad, [email protected], and Craig Sandefur, Regenesis, San Clemente CA

This presentation will focus on the application of Design Verification steps prior to field implementation with the goal of improved remedial performance outcomes. The goal is to determine what “lower-cost” field based methods might provide insights in the design and selection process of the most appropriate remedial techniques. Over the past 20 years, application of remedial substrates has had an uneven track record in terms of performance. It is recognized that in-situ remedial performance is the result of multiple factors.

Aquifer characteristics that provide the most insight into the remedial design and application

programs will be identified using traditional field methods. This presentation will focus on those Target Treatment Zone (TTZ) characteristics that directly affect application programs and ultimately remedial outcomes.

To assist design and application teams, a set of routine pre-application Design Verification steps were developed and performed on select project sites (N= +30). Using these steps to identify the relationship between COC mass storage and distribution units within the TTZ has contributed to an overall improvement in application programs and is a key element in higher remedial success rates.

Tools for Monitoring Contaminant Biodegradation when Combined with Colloidal Activated Carbon

Northington, Chad, [email protected], Kristen Thoreson, Stephanie Amick, and Craig Sandefur, Regenesis; San Clemente CA; and Jeremy Birnstingl, Regenesis; Bath, UK

The combined remedial approach of enhanced bioremediation with injectable activated carbon substrates offers a unique treatment method for quickly reducing contaminant concentrations in groundwater and destroying the contaminants. This combination provides a sustainable treatment option since the ability to biodegrade contaminants provides a mechanism to regenerate the sorptive capacity of the activated carbon over time. With increasing implementation of this approach, a question arises in how to confirm that the contaminants are actually degrading when they are sorbed to activated carbon and therefore cannot be monitored in a traditional manner. We

address this question by reviewing data that can be used to support the biodegradation of sorbed contaminants.

In a laboratory study, dual-soil porosity tanks were used to simulate back diffusion of TCE and evaluate the ability of colloidal activated carbon to treat this long-term problem. Effluent VOC concentrations were monitored throughout the study and microbial analysis was performed at the end of the study. Results include enhanced removal of total VOCs and multiple orders of magnitude greater microbial populations in the presence of colloidal activated carbon.

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In Situ Containment of PFAS Using Colloidal Activated Carbon

Northington, Chad, [email protected], Kristen Thoreson and Melinda Pham, Regenesis; San Clemente CA

With the increasing awareness of the widespread groundwater contamination associated with PFOA, PFOS, and other PFAS compounds, there is an established need for new and lower cost treatment options that can address the large, dilute plumes that these contaminants commonly form. At the present time, the accepted remediation method is to use pump and treat systems equipped with activated carbon. The costs associated with running these systems and replacing the carbon can be quite high. For that reason, the ability to implement an in situ barrier of activated carbon that can cut off and contain these plumes for many years with a single application affords a beneficial means to decrease or avoid the operating and maintenance costs in the existing aboveground systems. This presentation examines the use of a colloidal activated carbon that readily distributes within the subsurface, providing a method for injecting an in situ barrier of activated carbon for PFAS treatment.

Laboratory batch studies were conducted to measure the relative adsorption of PFOS, PFOA, PFHpA and PFBS with a distributable form of colloidal activated carbon. Results of these studies demonstrated that a field relevant dose of the colloidal activated carbon could reduce 100 mg/L of each PFAS compound tested by at least 99.9% and the relative adsorption followed in the order: PFOS > PFOA > PFHpA > PFBS, as has been observed with other activated carbons. In these experiments PFOS and PFOA were reduced to below the 2016 revised EPA health advisory limits of 70 ng/L. Additionally, performance data from a site in Canada that was injected with colloidal activated carbon, demonstrate that consistent results can be achieved in the field as shown in the laboratory. Finally, advanced groundwater transport modeling was completed to demonstrate containment longevity of the PFAS compounds by the colloidal activated carbon.

Effects of Organic Compounds and Ionic Strength on the Fate and Transport of Toxoplasma Gondii in Saturated Porous Media

Pullano, Christian, [email protected], and Tim Mutty, Clemson University, Clemson, SC; Coralie L’Ollivier, Aix-Marseille University, Marseille, France; Jitender Dubey, U.S. Department of Agriculture, Beltsville, MD; Aurélien Dumetre, Aix-Marseille University, Marseille, France; and Christophe Darnault, Clemson University, Clemson, SC

Toxoplasma gondii is a pathogenic microorganism that is currently a threat to public health. Understanding the fate and transport of T. gondii through the soil and groundwater is vital in determining the risk it poses to water resources and human health. The physico-chemical interactions between the groundwater and the bio colloid within an aquifer will dictate its mobility and its ability to infect humans. This research examines how various naturally occurring

groundwater chemistries containing organic compounds and monovalent and divalent salt solutions will alter the fate and transport of T. gondii.

Solutions containing various concentrations of humic acid, fulvic acid, sodium chloride, calcium chloride, and magnesium chloride were created to test the transport of T. gondii. These tests were performed in a saturated silica sand column with continuous flow in order to simulate the

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movement of groundwater through an aquifer. Organic solutions and salt solutions were pumped through the columns followed by a pulse of T. gondii oocysts. The pulse of T. gondii was followed by seven pore volumes of organic and salt solution in order to flush the oocyst through the simulated aquifer. The effluent exiting the columns was collected in tenth of pore volume increments in order to determine the factors associated with the transport of T. gondii. The effluent samples were then processed using qPCR in order to quantify the oocysts present in the solution. Contact angle and

surface tension measurements were made in order to establish surface properties of the solutions as they coat the oocysts and aquifer material and a non-reactive bromide tracer test was performed. Breakthrough curve results from the qPCR analysis were then compared to the non-reactive tracer tests in order to determine the parameters that dictate the transport of T. gondii in saturated porous media. Lastly, a model of the flow experiments was conducted in order to quantify the observed breakthough curves that were generated in the experiments and characterize their behavior.

Modeling Microbial Transport in Response to Bioaugmentation for In Situ Bioremediation of 1,4-Dioxane

Ramos-Garcia, Angel, [email protected], and David Freedman, Clemson University, Clemson, SC

1,4-Dioxane was used widely as a stabilizer for 1,1,1-trichloroethane and has emerged as an important groundwater contaminant throughout the United States. Due to its apparent recalcitrance and possible carcinogenicity, there is considerable interest in developing technically and economically feasible remediation strategies

In situ bioremediation is one approach. Microbes have been identified that are capable of aerobically biodegrading 1,4-dioxane through metabolic and cometabolic pathways. However, at many sites it appears that the necessary microbes are either lacking or present at very low densities. In such instances, bioaugmentation may be required. Although injection of microbial cultures into aquifers has gained wide acceptance, the practice is largely empirical. Models to predict the movement of bioaugmented microbes in porous media are lacking. Several studies have evaluated the role of various physical, chemical and biological factors on microbial transport and removal in natural subsurface environments, but little has been done to model migration through soil in response to bioaugmentation. Pseudonocardia and Rhodococcus are examples of microbes that are being considered for use in bioaugmentation. Transport of Pseudonocardia

poses interesting challenges, since they tend to clump together when grown to high densities, a property that may inhibit their movement in aquifers.

The primary objectives of this study were to characterize a new isolate obtained from a 1,4-dioxane-contaminated site capable of metabolizing the contaminant, and to develop a model that can predict the transport of microbes through soil, with a specific focus on bacteria capable of biodegrading 1,4-dioxane.

A strain capable of using 1,4-dioxane as it sole carbon and energy source was isolated from a contaminated site in the southeastern U.S. According to a whole-genome sequence comparison, the isolate is a new strain of Pseudonocardia dioxanivorans. The isolate designated as BERK-1 is characterized by less cell aggregation than CB1190. An evaluation for both strains mobility through different porous media is underway, preliminary results using sand columns with and without recirculation indicate that BERK-1 moves faster than CB1190 when recirculation is not applied, whereas transport rates will be comparable with recirculation.

A proposed model for microbial transport

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of 1,4-dioxane degraders (via metabolism and cometabolism carried out by propanotrophs) will be presented. The model takes into account advection and dispersion, growth, decay, attachment, and detachment. An experimental design for bench-scale columns to evaluate the transport model will also be presented. Transport of microbes that metabolize or cometabolize

1,4-dioxane will be compared. Once validated, the transport model will be integrated into a groundwater transport model. This will facilitate a comparison of metabolism and cometabolism and help delineate which approach is more advantageous under a variety of conditions, including the concentration of 1,4-dioxane in the contaminant plume.

A Comparison Study of Carbon Dioxide Flux from Two Fields During the Summer Growing Season in Clemson, SC Using an Eddy Covariance System

Reed, Henry, [email protected], and Scott Brame, Clemson University, Clemson, SC

The goal of this project was to determine the impact on carbon dioxide flux from different management styles of two agricultural fields in the Clemson area during the 2017 growing season. Data was collected at the Calhoun Field Laboratory (unofficially called the Bottoms) and the Church Field located in the Fants Grove region of the Clemson Forest at different times throughout the spring, summer, and fall. Carbon dioxide concentration, vertical wind speed, temperature, and air-water concentrations were collected 20 times per second using an eddy covariance (EC) tower. The EC tower was mounted on a trailer

and equipped with a LI-7500RS analyzer, an open path infrared CO2 analyzer, and a 3-D sonic anemometer.

The data was averaged at 30 minute intervals to create a net carbon dioxide flux that is the product of soil carbon dioxide flux minus the carbon dioxide removed from the air by plant respiration and atmospheric mixing. Between the beginning and end of the growing season, the net flux was expected to peak in the middle of the growing season. Daily fluctuations show a higher flux during the night when plant respiration is at a minimum.

Natural Source Zone Depletion at LNAPL Sites

Rhine, Elizabeth, [email protected], Geosyntec Consultants, Greenville, SC, and Steven Aufdenkampe, Norfolk Southern Corporation, Atlanta, GA

Natural Source Zone Depletion (NSZD) processes are naturally occurring at most petroleum release sites with light non-aqueous phase liquid (LNAPL). These processes, which include dissolution, volatilization, and biodegradation, result in mass loss of petroleum hydrocarbons. Contrary to prior assumptions, it is now understood that most LNAPL bodies are stable, do not migrate, and are not readily recoverable. Once the release is stopped, LNAPL bodies do not represent an infinite source.

With respect to saturation concerns, it is important to develop a LNAPL Conceptual Site Model (LCSM) that addresses if LNAPL is at risk of migrating, how much LNAPL is actually mobile and/or recoverable (i.e., transmissivity), and if there are any potential risk exposure scenarios if the LNAPL stays in place. Based on evidence at most LNAPL remediation sites, removal efforts typically leave behind residual LNAPL and produce limited source reduction. Cost-benefit considerations conclude that remedial efforts of

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the past may have caused more harm than good through energy and resource consumption and fail with respect to sustainability considerations. The net environmental benefit of active LNAPL remediation systems should be scrutinized in terms of whether a significant level of risk reduction can be achieved compared to NSZD. In many cases, the benefit of LNAPL recovery may be limited to the sense of doing something even though the actual change in conditions is likely to be negligible. By contrast, if left in place, NSZD processes are often more likely to efficiently address long-term site conditions.

In 2009, ITRC published the NSZD technical overview document Evaluating Natural Source Zone Depletion at Sites with LNAPL. Since then, additional research indicates much higher source attenuation rates than previously observed, further supporting NSZD as a viable part of an overall remediation strategy. Soil gas data collected using dynamic closed chamber samplers demonstrates that 90 to 99% of the flux actually occurs in the vadose zone, whereby methane generated through biodegradation bubbles toward the surface and approaches the shallow oxygen front where it is converted to carbon dioxide. The remainder of the

flux, approximately 1 to 10%, is to groundwater. In the past, practitioners have focused only on this groundwater pathway. Now that these processes are better understood, it is apparent that tremendous degradation is occurring in the vapor phase. While there are compositional concerns related to the vapor phase, there is little concern that LNAPL serves as an infinite source of environmental impact to groundwater. While LNAPL compositional concerns do exist and must be assessed and/or managed by institutional or engineering controls, LNAPL at most sites pose limited saturation concerns.

This presentation will discuss development of a LCMS to provide the regulatory agency and other stakeholders with the information necessary to support NSZD as a viable remedy for sites where LNAPL is not recoverable and poses no risk. NSZD is an extension of Monitored Natural Attenuation (MNA), which is already widely accepted by EPA and most state regulatory agencies, including SCDHEC. The State of South Carolina needs to consider updating regulations that allow for more risk-based closure measures that are based on the growing body of scientific knowledge of LNAPL and the rate at which NSZD is occurring.

Soil Blending: Amendment Reaction Rates and Soil Strength Recovery

Rossabi, Joseph, [email protected], Steve Markesic, John Haselow, and Jay Romano, Redox Tech, Cary, NC

Soil blending is an aggressive remedial technique that requires a focus of resources (equipment, personnel, and usually amendment) on a particular contaminated volume. It is often performed under time critical remediation drivers like property transfer and rapid construction, which will limit subsequent access to a site for additional cleanup or polishing. Soil and water samples are often collected soon after soil blending to confirm that target concentrations have been reached and new construction is typically scheduled to immediately follow successful remediation results. As a result, the soil blending strategy must be reliable, fast, and comprehensive.

Reaction rates between compounds are often measured in the laboratory using an excess of one of the compounds to derive a simple mathematical relation dependent on the concentration of the other compound, typically the concentration of target species or contaminant. The determined rates are typically approximated by a first order or pseudo first order rate constant despite the fact that the reactions between amendment and contaminant are rarely if ever first order reactions. Nevertheless, these rates are a useful starting point for evaluating the potential success of a remediation using a specific amendment. In soil blending applications, pseudo first order reactions

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can often be justified because a large amount of amendment is typically applied, satisfying the conditions necessary to simplify higher order reactions. An appropriate amendment can then be selected based on the requirements and constraints for the site including necessary reaction rates, effectiveness of the reaction, products of the reaction, cost, future use of the site, and timing of the future use.

An often-overlooked aspect of subsurface remediation is the rate of reaction in zones that are not well approximated by first order kinetics. In these areas outside of the main amendment application zone, relatively low concentrations of amendments and relatively low concentrations of target compounds confound the traditional engineering approach of assuming that first order (or pseudo first order) kinetics may be applied. In these zones, reaction rates are strongly influenced by the molar concentration of both the amendment and the contaminant and may be substantially different than most laboratory values. It is important to recognize differences in reaction rates when relying on diffusion, dissolution, or other potentially slow transport mechanism to ensure

proper remedial contact between amendment and contaminant.

Apart from meeting the cleanup objective, the future use for the site is probably the most critical parameter to consider when selecting an amendment and strategy for soil blending. Often the future use of the site includes recovery or improvement of soil strength to support construction of residential or commercial buildings or other engineered structures (playing fields, etc.). Although some sites (e.g., well drained sands) can recover their bearing capacity with minimal intervention, most sites will require more aggressive geotechnical intervention such as removal of water, compaction, use of geotextiles, blending in of an additional amendment for soil improvement (like Portland cement or lime), or a combination of these. Proper selection of a remediation amendment that is compatible with a soil improvement strategy or amendment that will enable the achievement and maintenance of soil strength goals without causing delays in the plans for future use is vital for most successful turnkey soil blending projects. Some successful strategies for achieving these goals will be presented.

In-Situ Geochemical Stabilization (ISGS) for Non-Aqueous Phase Liquid Treatment – Technical Assessment

Scalzi, Michael, [email protected], and Antonis Karachalios, Innovative Environmental Technology, Inc., Pipersville, PA

In-Situ Geochemical Stabilization (ISGS) technology entails the use of modified permanganate solution that targets mass removal and flux reduction of the NAPL. The introduction of the permanganate solution results to the migration of the oxidant through the treatment area and consequently to geochemical reactions that destroy the targeted contaminants that are present in the dissolved phase. As a result the NAPL starts to steadily lose its more labile components and “chemical weathering” or “hardening” occurs. Subsequently a net increase in viscosity of the organic material is observed, which yields a more stable, recalcitrant residual

mass. Additionally, both the insoluble manganese dioxide precipitate, that results from permanganate oxidation, and other mineral species included in the ISGS formulation accumulate along with the NAPL interface, resulting in the physically coating of the NAPL and thereby reducing the flux of dissolved-phase constituents of interest into the groundwater.

ISGS was implemented at a site located in northern New Jersey in order to decrease the source area NAPL present. Based on the post remedial data, the ISGS technology was found to be very effective in addressing the groundwater

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and the free product contamination in all five targeted monitoring wells (MW-11, MW-12, MW-13, MW-14 and MW-15).

In MW-11, the concentrations of almost all SVOC compounds decreased to levels below the laboratory detection limits, total BTEX concentrations decreased by 85%, while the concentrations of total alkanes have also reached non-detect levels. In MW-12 the concentrations of the SVOCs and total alkenes reached levels below the laboratory detection limits, while BTEX compounds overall decreased by 68%. In MW-13 the concentrations of all targeted SVOC compounds decreased considerably, while

naphthalene was the compound that was massively affected with the concentration decreasing from 1,920 μg/L in August 2013 to 1.18 μg/L in January 2014. In MW-14 the concentrations of all targeted compounds have decreased to levels below the laboratory detection limits except for benzene that decreased by 43%. Finally, in MW-15 the concentrations of almost every SVOC and BTEX compound have decreased to levels below the laboratory detection limits.

The free product that was present in the five wells, disappeared within 30 days of the implementation of the injection event.

Comparative Study for ZVI/Peroxide vs Ferric Iron Oxide Persulfate Activation Followed by Intrinsic Facultative, Biologically Mediated Processes

Scalzi, Michael, [email protected], and Antonis Karachalios, Innovative Environmental Technology, Inc., Pipersville, PA

An In-Situ Chemical Oxidation (ISCO) remedial process involves injecting an oxidizing agent, such as activated sodium persulfate (Na2S2O8), or other oxidant into the subsurface to destroy organic compounds. The persulfate anion (S2O82-) has a high redox potential and can be chemically activated to form the sulfate radical (SO42-•), which is a stronger oxidant. The sulfate free radical is a very potent oxidizing agent roughly equivalent to the hydroxyl radical generated using ozone or peroxide. Persulfate activation with iron requires a lower activation energy than thermal activation, which makes iron activated persulfate a more efficient and rapid way of degrading contaminants.

There are various methods of activating persulfate; heat, peroxide, divalent transition metals, trivalent transition metals and caustic, however, several of the activation mechanisms involve the use of potentially hazardous chemicals under extreme conditions (e.g., pH >11) while others are simply not conducive to sustained biological processes. By optimizing “post-oxidation” conditions for biological mineralization process, enhanced attenuation can be achieved.

The frequent “rebound” seen in ISCO programs is a result of the oxidant’s rapid consumption with no real mechanism for managing the desorption of targeted contaminant from the soil matrix. The two activation methods presented below have the advantage of utilizing both biotic and abiotic processes that include the use of free radical chemistry, oxidation chemistry and facultative biological attenuation. The potential combination of these processes extends oxidant and free radical residuals while enhancing the in-situ environment for biologically based attenuation of the constituents of interest (COI).

The abiotic portion of the ZVI/Peroxide activated persulfate method uses a unique blend of peroxyl, hydroxyl, evolved heat and sulfate free radicals which results to the oxidation of the COIs. This mixture allows Fenton-like reactions with long-lived sulfate free radical oxidation to occur, while the presence of zero valent iron acts as a catalyst for both reactions. The evolved heat is of value in situations where there is a high sorbed mass of the hydrophobic compounds of concern. Furthermore, as mentioned above,

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the decomposition products of the oxidation process are utilized in the subsurface to stimulate facultative biological degradation of the targeted compounds. After dissolved oxygen has been depleted in the treatment area following the oxidation process, sulfate (the by-product of the persulfate oxidation) may be used as an electron acceptor for co-metabolic progressions, a process termed sulfanogenesis.

The use of ferric iron to activate persulfate for the purpose of degrading organic compounds presents the additional advantage of quickly generating sulfate and ferrate radicals for ISCO treatment. Moreover, it also supports long-term, sustained, secondary bioremediation processes to manage residuals and prevent contaminant rebound.

Similar to the ZVI/Peroxide activation method described above, that process is achieved by enhancing the subsequent utilization of sulfate and iron as terminal electron acceptors for facultative redox reactions in order to improve biodegradation of any residual COIs.

The ferric activated method, similar in its chemistry to the peroxide, ZVI persulfate, differs in that it is an endothermic process while still providing no extreme pH conditions that can mobilize heavy metals causing secondary impact issues, while the presence of iron will sequester sulfur liberation during sulfate reduction reactions to minimize H2S formation. Moreover, the remedy combines treatment mechanisms thereby allowing for more cost-efficient dosing of the product.

Anisotropy of Hydraulic Conductivity in Piedmont Residual Soil and Saprolite

Schaeffer, Malcolm F., [email protected], HDR Engineering of the Carolinas, Charlotte, and Sarah K. Townsend-Colley, University of North Carolina at Charlotte, Charlotte, NC (formerly with HDR Engineering)

Anisotropy of hydraulic conductivity is a difficult property of an aquifer to determine. The ratio kh/kv for open borehole permeability tests, or Kz/Kr for slug tests (where kh is the horizontal conductivity, kv and Kz are the vertical hydraulic conductivity, and Kr is the radial hydraulic conductivity), is a critical parameter for groundwater modeling and thus contaminant transport, but is difficult to assess at the scale required. Tests for anisotropy yield different results depending on the scale (Kenoyer 1988). Pumping and tracer tests in granular aquifers measure large-scale anisotropy but yield only spatially averaged ratios (Kenoyer 1988). Field permeability tests and slug tests can measure small-scale anisotropy in the vicinity of the sampling location, but tend to be biased toward horizontal hydraulic conductivity (Freeze 1967). The presence of heterogeneous layers (as found in Piedmont residual soil and saprolite) in the large-scale domain can have the effect of increasing kh/kv ratios as much as 1000 or more in regional groundwater flow systems (Winter 1976).

Freeze and Cherry (1979) give kh/kv ratios of

sediment core samples of 1 to 3. Based on tracer tests and piezometer (field) measurements, Kenoyer (1988) estimated a lower and upper bound of 2.4 and 8.3 kh/kv ratios, respectively, for granular materials. Burger and Belitz (1997) measured kh/kv ratios of 1.33 to 1.57 in unconsolidated sands based on an integrated field and laboratory method. Guo et al. (2015) derived a theoretical upper limit of the kh/kv ratio of approximately 2.5 for homogeneous granular materials.

Estimating the anisotropy of hydraulic conductivity from field permeability tests in boreholes is problematic as the formulae assume a transformation ratio (m) or in the case of the slug tests the ratio of the vertical to the radial (horizontal) hydraulic conductivity to take into account the influence of kv in the tested interval. The flush bottom falling head field test calculates a mean hydraulic conductivity.

In this study, a database of kh and kv hydraulic conductivity measurements from six sites in the Carolina Piedmont is utilized to make generalizations about kh/kv ratio, the

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transformation ratio, m, (m=√(kh/kv)), and Kz/Kr ratio for Piedmont residual soil and saprolite for the two conceptual models of Piedmont bedrock proposed by Harned and Daniel (1992). The first conceptual model is layered/foliated bedrock while the second conceptual model is massive/plutonic bedrock; the bedrock model type has implications for the nature of a resultant aquifer system and thus hydraulic conductivity. The horizontal hydraulic conductivity measurements (N = 233) were made in the field using falling and constant head open well point tests (73 total) following the U. S. Bureau of Reclamation (1995) procedure and slug tests (160 total) using the guidelines of NCDENR (2007). The vertical hydraulic conductivity measurements (N = 183) were made in the field using falling head flush bottom tests (54 total) utilizing the U. S. Bureau of Reclamation (1995) procedure and in the laboratory (129 total) on undisturbed samples (Shelby tube samples) utilizing the method outlined in ASTM D5084.

Sites 1 and 6 are located in the Charlotte terrane within the Carolina superterrane and are underlain by a meta-igneous complex consisting of meta-quartz diorite and meta-diorite intruded by meta-diabase dikes. Site 2 is in the Milton terrane and is underlain by a complex, folded, and faulted sequence of interlayered mica schist, schistose mica gneiss, augen gneiss, flaser gneiss, quartzo-feldspathic gneiss, biotite gneiss, with minor hornblende schist and gneiss. Site 3 is in the Charlotte terrane within the Carolina superterrane and is underlain by a felsic to mafic meta-volcanic sequence of tuffs and flows metamorphosed to amphibolite grade. Site 4 is located in the Cat Square terrane within the Inner Piedmont terrane and consists of interlayered mica gneiss, mica schist, sillimanite-mica schist, with minor biotite gneiss. Site 5 is located primarily in the Charlotte terrane with a portion underlain by the Kings Mountain terrane within the Carolina superterrane and is underlain by an igneous and meta-igneous complex consisting of meta-quartz diorite and metavolcanic rocks of granodioritic composition intruded by biotite granite. Sites 1, 5, and 6 fall under the massive/plutonic conceptual bedrock model, while Sites 2, 3, and 4 fall under the layered/

foliated bedrock model.

The vertical and horizontal hydraulic conductivity data were compiled into two defined hydrostratigraphic layers based on the Standard Penetration Test conducted in the boreholes and Rock Core Recovery (REC) and Rock Quality Designation (RQD) of recovered rock during coring in the boreholes. The layers are M1 - SPT, N < 50 and M2 - N > 50 or REC < 50% (Schaeffer 2009). The 2-Sample T-Test (at the 0.05 significance level) comparing the log means (hydraulic conductivity data have a log-normal distribution; Schaeffer 2009) of the field and laboratory kv measurements found that the means are equal and therefore both types of measurements were combined in the additional statistical testing. Statistical analysis (2 Sample T-Tests, at the 0.05 significance level) comparing the means of both the horizontal and the vertical hydraulic conductivity at the six sites showed they were statistical the same for the two layers, M1 and M2, except in one case. Therefore, the combined M1 and M2 data sets were used to analyze the hydraulic conductivity anisotropy of the residual soil and saprolite (regolith) for the six sites and the data grouped into the two conceptual models of Piedmont bedrock. 2-Sample T-Tests (at the 0.05 significance level) comparing the horizontal and vertical hydraulic conductivity of the six sites and the two bedrock models show their means are not equal and kh is always greater than kv.

The estimated kh/kv ratios, the transformation ratios (m), and Kz/Kr ratios estimated from the mean values of the data sets are shown in Table 1. The kh/kv ratios for the three layered/foliated sites range from 4.5 to 9.1 (m from 2.1 to 3.0) and for the three massive/plutonic sites from 8.8 to 23.6 (m from 3.0 to 4.9). The kh/kv ratio for the combined layered/foliated model is 6.4 (m = 2.5) and for the massive/plutonic model is 11.9 (m = 3.4) or 9.7 (m = 3.1) when data from Site 6 is not included due to its high kh/kv ratio.

The open borehole falling and constant head field test data and the slug test data were reduced assuming a kh/kv ratio of 1 (m = 1) and Kz/Kr ratio of 1, respectively. Thirty in-situ field tests and six

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slug tests from the data set were used to estimate the relative percent difference with respect to kh/kv or Kz/Kr ratio of 1 using kh/kv ratios of 100 (m = 10; Kz/Kr = 0.01), 10 (m = 3.16; Kz/Kr = 0.1), 5 (m = 2.24; Kz/Kr = 0.2), and 2.5 (m = 1.58; Kz/Kr = 0.4) for comparison. The average percent differences plus and minus one standard deviation are 50.3+2.9%: 45.8+3.5% (in-situ field test: slug test), 28.8+1.9%:23.5+2.9%, 21.1+1.5%:17.3+2.4%, and 12.6+1.0%:10.0+1.6% for kh/kv ratios of 100, 10, 5 and 2.5, respectively. The field tests provide semi-quantitative values of hydraulic conductivity and if performed correctly they provide results that are sufficiently accurate for most purposes (U.S. Bureau of Reclamation 1995). The relative percent differences are likely within the range of the accuracy of the field and laboratory methods used due to the inherent assumptions used in the various equations for estimating the hydraulic conductivity and the heterogeneous nature of Piedmont residual soil and saprolite.

The results in Table 1 are approximations of the actual in-situ ratios and are consistent with the lower and upper bound kh/kv ratios of 2.4 and 8.3 estimated by Kenoyer (1988) for granular materials (with the exception of the kh/kv ratio of 23.6 for Site 6). The ratios presented for the two conceptual models in Table 1 are reasonable approximations

of the anisotrophy ratios for use in field in-situ and slug permeability testing and data reduction and in groundwater modeling scenarios in Piedmont residual soil and saprolite.

ReferencesAmerican Society of Testing and Materials. 2010. D5084, Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter: ASTM International, West Conshohocken, PA, DOI: 10.1520/D5084-1.Bouwer, H. 1989. The Bouwer and Rice slug test – an update: Ground Water, vol. 27, no. 3, pp. 304-309.Bouwer, H. and R. C. Rice. 1976. A slug test method for determining hydraulic conductivity of unconfined aquifers with completely or partially penetrating wells: Water Resources Research, vol. 12, no. 3, pp. 423-428.Burger. R. L. and K. Belitz. 1997. Measurement of anisotropic hydraulic conductivity in unconsolidated sands: A case study from a shoreface deposit, Oyster, Virginia: Water Resources Research, vol. 33, no. 6, pp. 1515-1522.Freeze, R. A. 1967. Quantitative interpretation of regional groundwater flow patterns as an aid to water balance studies: International Association of Scientific Hydrology, General Assembly of Bern, Publication 78, pp. 154-173.Freeze, R. A. and Cherry, J. 1979. Groundwater:

Table 1: kh/kv ratio, the transformation ratio, m, and kv/kr ratio of soil and saprolite at the six sites and for the two conceptual models of Piedmont bedrock

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Prentice-Hall, Englewood Cliffs, New Jersey, 604p.Guo, P., Y. Liu, and D. Stolle. 2015. Limit of anisotropic hydraulic conductivity ratio of homogeneous granular materials: Vadose Zone Journal, v.14, no. 11, DOI: https://doi.org/10.2136/vzj2015.01.0015Kenoyer, G. J. 1988. Tracer test analysis of anisotropy in hydraulic conductivity of granular aquifers: Groundwater Monitoring & Remediation, v. 8, pp. 67-70.North Carolina Department of Environment and Natural Resources. 2007. “Performance and Analysis of Aquifer Slug Tests and Pumping Tests Policy,” May 31, 2007.Schaeffer, M. F., 2009, Hydraulic conductivity of

Carolina Piedmont soil and bedrock: Is a transition zone present between the regolith and bedrock?: 17th Annual David S. Snipes/Clemson Hydrogeology Symposium, April 2, 2009, pp. 32-36.U.S. Bureau of Reclamation. 1995. Ground Water Manual: A Guide for the Investigation, Development, and Management of Ground-Water Resources: Department of the Interior, U. S. Bureau of Reclamation, 2nd Edition, 661p. Winter, T. C. 1976. Numerical simulation analysis of the interaction of lakes and groundwater: United States Geological Survey Professional Paper 1001, 45p.Zlotnik, V. 1994. Interpretation of slug and packer tests in anisotropic aquifers: Ground Water, vol. 32, no. 5, pp 761-766.

Biodegradation of Chlorobenzenes and Nitrotoluenes at an Industrial Site in South America

Silva Lemes, Maria Cristina, [email protected], and David Freedman, Clemson University, Clemson, SC; James Henderson, Dupont, Charlotte, NC; and Erin Mack, DuPont, Newark, DE

This study was conducted for a large industrial facility in South America with a complex mixture of constituents of concern (COCs) in soil and groundwater, including chlorobenzenes, analines, and nitroaromatics. The overall objective was to further assess the effect of pH and nutrients on the biodegradation rates of the target compounds on aerobic biodegradation of chlorobenzene (CB) and 1,2-dichlorobenzene (1,2-DCB), and anaerobic reduction of 2,6-dinitrotoluene (2,6-DNT) and 4-nitrotoluene (4-NT).

Using soil and groundwater from the site, microcosm cultures were developed that aerobically degrade CB (5.0 mg/L) and 1,2-DCB (1.0 mg/L) and anaerobically degrade 2,6-DNT (6.0 mg/L) and 4-NT (3.0 mg/L). Lactate was used as the electron donor for reduction of the nitrotoluenes. To address the effect of pH and nutrients, 4 sets of microcosm treatments (in triplicate) were developed: with and without pH adjustment, and with and without nutrients added for each COC. This resulted in 24 aerobic and 24 anaerobic microcosms, plus 3 water controls and 6 autoclaved controls.

In the aerobic microcosms, CB was consumed in 15 to 45 days. Addition of nutrients accelerated the rate of degradation. pH adjustment was not a factor, since the groundwater pH was only slightly acidic (6.5). This was unexpected, since uncontaminated soils at the site have pH levels below 6 and low pH was expected to slow the rate of biodegradation. 1,2-DCB has persisted through 200 days of incubation. 2,6-DNT, 2,4-DNT, and isopropylanaline were also biodegraded under aerobic conditions. The results are consistent with the expectation for aerobic biodegradation of monoaromatic compounds, with the exception of 1,2-DCB. Bioaugmentation of several microcosms with a 1,2-DCB enrichment culture is in progress.

In the anaerobic microcosms, 4-NT was stoichiometrically reduced to 4-aminotoluene within 45 days. Addition of nutrients and pH adjustment did not have a noticeable impact on the rate. The rate of reduction of 2,6-DNT to 2-amino-6-nitrotoluene and 2,6-diaminotoluene has been comparatively slower, with only partial reduction observed after 200 days of incubation. Increased rates of lactate addition are being applied in an

https://doi.org/10.2136/vzj2015.01.0015

https://doi.org/10.2136/vzj2015.01.0015

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effort to accelerate the reduction process. The background level of sulfate in the groundwater (1.9 mM) has been consumed, indicating the sulfate is no longer a competing electron acceptor.

The results of this study indicate that most of the contaminants will biodegrade aerobically and the rate of biodegradation may be improved by

addition of nutrients. pH adjustment for this site does not appear to be necessary. Nevertheless, providing oxygen to the contaminated groundwater poses significant challenges. Anaerobic reduction of the nitroaromatics to aminoaromatics is also possible. Consideration must be given to whether or not aminoaromatics are an acceptable remediation endpoint.

Challenges in the Field and Laboratory to High-Throughput PFAS Analysis

Somerville, Stephen, [email protected], and Dan Wright, Shealy Environmental Services/EQI, West Columbia, SC

Poly- and perfluorinated alkyl substances (PFAS) have emerged as an important class of environmental contaminants in the past decade, as they are highly persistent in the environment and show toxicity at very low levels of contamination. These substances are commonly used in the production of a wide variety of consumer products including carpets, apparel, food packaging, and fire suppressants. The stability and relatively low reactivity of these compounds means that any environmental release is cause for concern. The use of firefighting materials on military bases has become an area of specific focus for environmental monitoring and remediation efforts, as they contain PFAS at very high concentrations and are used liberally in outdoor training exercises.

Laboratories interested in starting robust, defensible PFAS analysis have several issues to contend with including potential contamination from common lab supplies and sample collection, the presence of a variety of regulatory programs requiring different analytical approaches and levels of quality assurance, and highly contaminated field samples. Further, the complexity of field sample

analysis compared with ideal conditions during method development requires labs to be flexible and forward-looking during initial startup and when shifting into production level analysis.

The use of isotope dilution quantitation, required by regulations from the Department of Defense (DoD), and the use of a more intricate analysis technology (LC/MS/MS) than is typical in the environmental arena add other levels of complexity for environmental labs. Acquisition of standards and consumables, calculations, data management and reporting, highly-contaminated samples, and method validation can all add surprises to the startup of a new PFAS analysis lab. Additionally, common PFAS of concern are a large and growing class, with clients and regulatory agencies continually requesting characterization and monitoring of new analytes. Continuously evolving state- and project-specific action limits also add to the challenge of establishing the various laboratory reporting limits. Established and clearly documented sampling protocols and experience and experimentation in the laboratory will ultimately result in reliable and robust procedures and results.

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Evaluating Thermal Treatment as a Viable Mechanism for the Remediation of Elemental Mercury

Spain, Thomas, [email protected], and Ronald Falta, Clemson University, Clemson, SC

Thermal remediation is an established method for the remediation of volatile organic compounds (VOCs). Applying thermal remediation for the remediation of elemental mercury was successfully applied by Kunkel et al., 2006 in the laboratory scale. Before the technology can be applied to the bench and field scales, the thermal treatment for mercury needs to better constrained using numerical simulation.

The Department of Energy’s TOUGH2/TMVOC Code was developed at the Lawrence Berkeley National Laboratory and was used to determine the effectiveness of thermal treatment to remediate elemental mercury. TMVOC is a three phase non-isothermal numerical simulator for water, gas, and VOCs in porous media and was used to simulate the removal of elemental mercury due to its liquid state at 25°C and relatively high vapor pressure at

elevated temperatures.

The overlying work was conducted as feasibility research for the maturation of thermal treatment for elemental mercury. Multiphase flow, contaminant phase change, and transport processes were investigated as mercury undergoes thermal mass transfer. Temperature, pressure and mass injection rates were evaluated to better constrain the thermal treatment process for the treatment of mercury. The study consists of three key elements: 1) Numerical simulation of one dimensional thermal treatment experiments outlined by Kunkel et al., 2006 for the treatment of elemental mercury 2) Development of ex-situ and in-situ thermal treatment simulation under varying conditions for the removal of elemental mercury and 3) A feasibility assessment of thermal treatment for the removal of elemental mercury in porous media.

Occurrence and Control of Legacy and Emerging Perfluoroalkyl Substances in North Carolina

Sun, Mei, [email protected], University of North Carolina at Charlotte, Charlotte, NC; Elisa Arevalo, North Carolina State University, Raleigh, NC; Andrew Lindstrom and Mark Strynar, US EPA National Exposure Research Laboratory, Durham, NC; and Detlef Knappe, North Carolina State University, Raleigh, NC

Per- and polyfluoroalkyl substances (PFASs) are persistent organic pollutants of emerging concern. Long-chain PFASs are being replaced by short-chain PFASs and fluorinated alternatives. For ten legacy PFASs and seven recently discovered perfluoroalkyl ether carboxylic acids (PFECAs), we investigated (1) their occurrence in the Cape Fear River (CFR) watershed of North Carolina (NC) and (2) their fate in water treatment processes. In the headwater region of the CFR basin, PFECAs were not detected in raw water of a drinking water treatment plant (DWTP), but concentrations of legacy PFASs were high. The

US Environmental Protection Agency’s lifetime health advisory level (70 ng/L) for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) was exceeded on 57 of 127 sampling days. PFOS and PFOA concentrations were similar to results observed in the same area in 2006, but the speciation of perfluoroalkyl carboxylic acids shifted from longer-chain in 2006 to shorter-chain in 2013. In raw water of a DWTP downstream of a PFAS manufacturer, the mean concentration of perfluoro-2-propoxypropanoic acid, a replacement for PFOA with the trade name of GenX, was 631 ng/L (n=37). Six other PFECAs were detected with

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three exhibiting chromatographic peak areas up to 15 times that of GenX. At this DWTP, PFAS removal by coagulation, ozonation, biofiltration, and disinfection was negligible. At another affected DWTP, post-filter granular activated carbon adsorption led to partial removal of GenX. Our research results received attention from many stakeholders, including state regulators, local

utilities, local officials, and the public. The chemical manufacturer has agreed to stop discharging GenX into the river, and state regulators have required the fluorochemical manufacturer to stop discharging PFESAs and other PFASs. Current monitoring results illustrate that fluorochemical levels have decreased dramatically.

Using Fossils to Determine the Geologic Origin of the Hagood Millstone (Pickens, SC)

Thomas, Morgan, [email protected], and Kelly Lazar, Clemson University, Clemson, SC; and N. Adam Smith, Bob Campbell Geology Museum, Clemson, SC

Paleontological investigation of millstones from the 18th and 19th centuries can provide insight into the origin of the millstone, which in turn provides information about local history regarding whether the rock for millstone construction was quarried locally, regionally, or imported over longer distances. For example, some North American millstones are known to have originated in France and other parts of Europe. The goal of this study was to determine whether the millstone from Hagood Mill in Pickens, SC, is comprised of Ohio chert (Illinois Basin) or French buhr (Paris Basin) by relating the fossil content of the millstone to previous studies of rocks from these two origins. An abundance of gastropod fossils were found macroscopically, as well as indications

of microscopic charophytes. On the surface of the millstone, there are an average of 12.56 visible gastropod fossils for every 100 cm^2. The Hagood Millstone includes numerous charophyte fossils, which have never been documented in samples of Ohio chert. Their relative high abundance in most of the Hagood millstone thin sections indicates an affinity with French buhr. The average size of the charophyte gyrogonites found in the Hagood Millstone is 0.88 mm in diameter compared to the average size of 0.93 mm in diameter of those found in French buhr. Overall, the data strongly suggest that the Hagood Millstone is comprised of French buhr and would have been transported to its current location in the 19th century.

Groundwater Monitoring Networks at the South Carolina Department of Natural Resources

Williams, Joshua, [email protected], S.C. Department of Natural Resources, Columbia, SC; Brooke Czwartacki, S.C. Department of Natural Resources, Charleston, SC; and Scott Harder, S.C. Department of Natural Resources, Clemson, SC

The South Carolina Department of Natural Resources (DNR) collects continuous and periodic groundwater- level data from a network of 170 wells—155 in the Coastal Plain Province and 15 in the Piedmont Province. One hundred thirty-seven of the wells are equipped with automated data loggers that are programmed to

record groundwater levels on an hourly basis; water levels in the remaining thirty-three wells are measured manually on a bimonthly basis. Data from these wells are used to assess drought conditions and long-term trends in storage, to monitor groundwater availability and the effects of groundwater development, to study interactions

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between groundwater and surface water, to calibrate groundwater flow models, and to note changes in horizontal and vertical flow directions.

Wells range in depth from 20 to 3,708 feet. In the Coastal Plain, 7 wells are completed in the surficial aquifer, 22 in the Gordon, 18 in the Upper Floridan, 14 in the Middle Floridan, 41 in the Crouch Branch, 43 in the McQueen Branch, 3 in the Charleston, 3 in the Gramling, 2 in the Gramling confining unit, and 2 in the crystalline bedrock aquifer. In the Piedmont, 4 wells are completed in the shallow aquifer system and 11 in the crystalline bedrock aquifer. The period of record ranges from 1955 to 2018, with over half of the wells having 15 or more years of data.

A real-time monitoring network was created in 2014 with a total of 9 stations. Data collected from these stations are used by the DNR Climatology Office and the State’s Drought Committee to improve decision making regarding drought designations. Synoptic measurements from a second, larger network of about 600 wells are collected about every three years to produce

statewide potentiometric maps of the major Coastal Plain aquifers—Floridan, Crouch Branch, and McQueen Branch. Such maps are used to discern long-term trends in groundwater storage and to delineate existing and emerging cones of depression. DNR also measures specific conductance in eleven wells along the coast to monitor for saltwater intrusion. Water- level data, data reports, and potentiometric maps can be downloaded from the DNR webpage.

Recently, some updates have been made to the network. These updates include the addition of a five-well cluster site in Sumter County, the addition of three monitoring wells in Aiken County, and the installation of three real-time monitoring telemetry systems. The network also has been linked to the National Ground-Water Monitoring Network (NGWMN). Water- level data for 438 SCDNR wells can be viewed or downloaded from NGWMN. Future plans for the network include the addition of a deeper well in Calhoun and Georgetown Counties and to create a shallow water-table network of 10 new wells.

A Comparative Study of Wire and Plastic Fiber Optic Cable Extensometers

Williams, Reid, [email protected], Scott Brame, and Scott DeWolf, Clemson University, Clemson, SC

Wire and rod extensometers have been the traditional means of measuring slope movements. A relatively new method of measuring movement is using plastic fiber optic cables. The advantage of a fiber optic system is its low cost (<$20) compared with a wire or rod extensometer system that can run in the hundreds of dollars depending on whether you make it yourself or use an off the shelf system. To assess the relative merits of each method, a comparison study was conducted that analyzed both systems from development to field deployment.

We developed a cost-efficient wire extensometer system using an existing temperature datalogger and adding a potentiometer coupled to a pulley. This resulted in a system that could collect

temperature and wire movement data every 30 minutes for up to a year without changing the battery for less than $200. The fiber optic system, while considerably cheaper per unit, does not have data logger capabilities and data collection necessitates a field visit.

To compare the field installation process for each, both systems were deployed side by side along a section of the Rim of The Gap Trail at Caesars Head State Park in Cleveland, SC. This site was chosen because of its propensity for mass wasting events. While significant movement is not expected in the near future along this section of trail, we wanted to pick a challenging location that would test the limitations of both systems.

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Quantitative Estimation of LNAPL Recovery Endpoints: A Case Study

Zenker, Matthew, [email protected], Steven Pires, and Darin Albrecht, AECOM

The remediation of light nonaqueous phase liquids (LNAPLs) has historically been managed by the use of physical recovery techniques such as skimming, dual phase recovery or multiphase extraction. Following installation and operation of these systems, volumetric LNAPL recovery typically decreases rapidly and stabilizes at a value much lower than initial rates. Despite this rapid decrease, operation of LNAPL recovery systems often continue for several years beyond this stabilized (asymptotic) condition. Ongoing operation of these systems can be due to several factors such as unrealistic expectations of the inherent capability of physical recovery methods, or simply a desire to recover any LNAPL, regardless of how limited the volume. Based on guidance developed by the Interstate Technology and Regulatory Council (ITRC), however, the use of LNAPL transmissivity as a metric has allowed some stakeholders to achieve final shutdown of active LNAPL recovery operations. The use of transmissivity, however, cannot always be relied upon as a standalone metric to evaluate LNAPL recovery endpoints. Additional conceptual site model data such as LNAPL extent, residual saturation values and historic cumulative recovery rates can be utilized to demonstrate LNAPL recovery termination beyond the use of transmissivity alone.

At a site impacted with LNAPL derived from crude oil, historic remedial activities involved the use of active skimming. Following seven years of active skimming and the recovery of over 15,000 gallons of LNAPL, transmissivity values (calculated from both periodic baildown and cumulative recovery data) and LNAPL recovery rates were observed to have significantly decreased. Despite these encouraging results, concerns over potential remaining source zones and/or sub-optimal recovery operations suggested that additional lines

of evidence to support termination of skimming operations were required. A high resolution investigation utilizing laser induced fluorescence (LIF) was first utilized to delineate the extent of LNAPL impacts. Following the LIF investigation, several undisturbed soil cores were collected and submitted for LIF frozen core analysis. This analysis first involves the scanning of collected soil cores, frozen immediately upon collection, for LIF response in a laboratory setting. Following LIF analysis, the frozen cores are submitted for laboratory analysis of LNAPL pore fluid saturation. This technique therefore allows for the direct comparison of the LIF signal to soil pore fluid saturation.

The high resolution LIF results were utilized to develop a three-dimensional rendering of the LNAPL body using Earth Volumetric Studio (EVS) software. By combining the three dimensional rendering with the results of the frozen core analysis, a total remaining in-place volume of LNAPL was calculated. The extent of remaining mobile LNAPL was also estimated using a database of historical residual saturation values. The extent of remaining mobile LNAPL was also calculated using a decline curve analysis, which yielded an estimate very similar to that calculated using the three dimensional rendering. These converging lines of evidence ultimately provided stakeholders with a realistic estimate of the remaining operational life of the skimming system and better assurance that the selected remedial technique could adequately address the LNAPL body. This presentation will present an overview of the LNAPL conceptual site model and briefly discuss the calculation techniques (e.g., frozen core analysis, decline curve analysis, EVS methodology) utilized to develop the remediation endpoints.

2018 Exhibitors

Bill Barnes A.E. Drilling Services, LLC

30 Grant Park PlacePiedmont, SC 29673

(864) [email protected]

Dan MartinA & D Environmental Services

1741 Calks Ferry Rd.Lexington, SC 29073


Allison QueenPace Analytical

9800 Kincey Ave., Suite 100Huntersville, NC 28078


Tyler MesserEON Products, Inc.

3230 Industrial Way S.W., Suite BSnellville, GA 30039


Adam PhillipsPrism Laboratories

449 Springbook RoadCharlotte, NC 28217

(919) 451-3370 (800) 529-6364 [email protected]

Brian ChewEnviro-Equipment Inc

11180 Downs RoadPineville, NC 28134


Michael L. Kilpatrick IIShealy Environmental Services

106 Vantage Point Dr.West Columbia, SC 29172


2018 Exhibitors

Justin SasserPine Environmental

4037 Darling Court Suite DLilburn, GA 30047


Tim ColganCarus Corporation

315 5th StreetPeru, IL 61354


H.W. Harter IIICarbon Service & Equipment Co.

PO Box 1062Chapin, SC 29036


Jorgen BergstromGEL Geophysics, LLC

P.O. Box 30712Charleston, SC 29417


Peter ByerSAEDACCO Inc.

9088 Northfield DriveFort Mill, SC 29707


Kenneth LipscombAMS Inc.

3803 Grahams Port LaneSnellville, Georgia 30039


Brian StricklandGeo Lab Drilling

PO Box 1169Dacula, GA 30019


2018 Exhibitors

Chris PaffordAnalytical Environmental Services, Inc. (AES)

3080 Presidential Drive Atlanta, GA 30340


Brian ShinallFruits & Associates, Inc.500 North Point Parkway

Acworth, GA 30102(770) 974-6999

[email protected]

Sherri ScottTersus Environmental

1116 Colonial Club RoadWake Forest, NC 27587

(919) 453-5577 Ext. [email protected]

Bob KelleyCascade Technical Services

Charlotte, NC(908) 510-3835

[email protected]

Dearal RodgersElite Techniques, Inc.1817 Bishopville Hwy

Camden, SC 29020 (803) 425-7324

[email protected]

Gary EllingworthParratt-Wolff, Inc.501 Millstone Drive

Hillsborough, NC 27278(919) 644-2814

[email protected]

Jeanie DonahueGeoSearch

3006 Bee Caves Rd. Suite A-230Austin, TX 78746

(407) 718-2580 (888) [email protected]

2018 Exhibitors

Nathan ThackerAST Environmental

785 Acorn DriveHarrisonburg, VA 22802


Chris SchappellGeologic Exploration

176 Commerce BoulevardStatesville, NC 28625

(704) 872-7686 (c) [email protected]

Jim FineisAtlas Geo Sampling 120 Nottaway Lane

Alpharetta, SC 30009(770) 883-3372

[email protected]

Garrett RosenbaumERIS-Environmental Risk Information Services

2 Bent Twig LaneCharleston, SC 29407


Brian Palys, CPGORIN Technologies, LLC.

405 Investment CourtVerona, WI 53593


Eric Cross, P.G.Pyramid Geophysics503 Industrial AvenueGreensboro, NC 27406


Mark VestalCCI Environmental Services

281 Lane ParkwaySalisbury, NC 28146


2018 Exhibitors

Alan HewettRogers & Callcott Environmental

P.O. Box 5655Greenville, SC 29606


Kendall SutlerSGS Environment, Health and Safety

4405 Vineland RoadOrlando, FL 32811


Ruth MckeownSoilVision Systems Ltd.120 - 502 Wellman Cres. Saskatoon, SK S7T 0J1

Canada(306) 447-3324

[email protected]

Clemson University 140 Discovery LaneClemson, SC 29634

864-656-4600www.clemson.edu/geomuseum

Hours of Operation Monday-Sunday 10 am - 5 pm

The BCGM is actively seeking industry sponsors to assist us with providing

educational opportunities in the Earth Sciences to the Upstate of SC and

surrounding regions. Please contact us to learn more ([email protected]).

GEOLOGY MUSEUM

http://www.clemson.edu/geomuseum

Dave and Tracy CampbellCampbell Geosciences Inc.

15 Leisure LaneWeaverville NC 28787

(828) [email protected]@bellsouth.net

Bill SlackFRx, Inc.

P.O. Box 498292Cincinnati, OH 45249

(513) 469 [email protected]

Shaun MalinHRP Associates, Inc.

1327 Miller Road, Suite DGreenville, SC 29607


Stephen C. Godfrey

Cliff R. Lundgren, P.G.Blue Ridge Environmental Services, Inc.

2315 Kings Road Ext.Shelby, NC 28152

Cell: (980) 722-3535Work: (704) 482-2111

[email protected]

Mark HoslerSensible Solutions Environmental

P.O. Box 3074Chapel Hill, NC 27515-3074


Charlie Isham Scott Brown

Civil & Environmental Consultants, Inc.530 Howell Rd., Ste. 203,

Greenville, SC 296151900 Center Park Dr, Ste. A Charlotte, NC 28217

(844) 574-4331 (980) 237-0373

[email protected] [email protected]

Kathy WebbSynTerra Corp

148 River Street, Suite 220Greenville SC 29601


Anthony FerrariEarthCon Consultants, Inc.

1880 West Oak PkwyBuilding 100, Suite 106

Marietta, GA 30062(770) 973-2100

[email protected]

Sibyl HendleyHole Products

1725 Corporate Drive, Suite 340 Norcross, GA 30093


John HaselowRedox Tech, LLC200 Quade DriveCary, NC 27513(919) 678-0140

[email protected]

Robert Workman, PG, CIH CRB Geological & Environmental Services, Inc.

5000 Old Buncombe Road, Suite 21Greenville, SC 29609

Office (864) 283-2000 ext. 101 [email protected]

2018 Sponsors

GEOL 3700 students descending into the Subway at Zion National Park

George MaaloufRogers and Callcott

Greenville/Columbia, SC(864) 232-1556

[email protected]

David FullerTestAmerica

2838-B Queen City DriveCharlotte, NC 28208


26th Annual David S. Snipes/Clemson Hydrogeology Symposium · David S.Snipes/Clemson Hydrogeology...

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Transcript of 26th Annual David S. Snipes/Clemson Hydrogeology Symposium · David S.Snipes/Clemson Hydrogeology...