Relating Manufacturing Processes and Sample Location to the Composition and Properties of MGP Tars
Scott C. Hauswirth, University of North Carolina at Chapel Hill, Chapel Hill, NC
Pamela Schultz Birak, University of North Carolina at Chapel Hill, Chapel Hill, NC
Cass T. Miller, University of North Carolina at Chapel Hill, Chapel Hill, NC

Ground-Penetrating Radar:  Enhanced 3D Graphics Using Low-Cost Visualization Software
Gary G. LaFrance, Civil Engineering Consultant, Harrisburg, PA

A Comparison of Three Soil Characterization Methods on a Soil Formed in Sandy Glacial Outwash
Michael W. Morris, Jacobs Engineering, Bourne, MA
Aimee Comeau, ECC, Otis ANGB, MA
John T. Ammons, University of Tennessee, Knoxville, TN
Ryan Blair, University of Tennessee, Knoxville, TN

Relating Manufacturing Processes and Sample Location to the Composition and Properties of MGP Tars

Student Presenter

Scott C. Hauswirth, University of North Carolina at Chapel Hill, 148 Rosenau Hall, CB# 7431, Chapel Hill, NC 27599-7431, U.S.A., Tel: 919-966-6332, Fax: 919-966-7911, Email: shauswirth@unc.edu:
Pamela Schultz Birak, University of North Carolina at Chapel Hill, 148 Rosenau Hall, CB# 7431, Chapel Hill, NC 27599-7431, U.S.A., Tel: 919-966-6332, Fax: 919-966-7911, Email: pamela_birak@unc.edu
Cass T. Miller, University of North Carolina at Chapel Hill, 148 Rosenau Hall, CB# 7431, Chapel Hill, NC 27599-7431, U.S.A., Tel: 919-966-1024, Fax: 919-966-7911, Email: casey_miller@unc.edu

The remediation of former manufactured gas plants (MGPs) presents a major challenge to the environmental industry.  MGP tars, the primary contaminant at these sites, are viscous, usually denser than water, contain carcinogenic PAHs with low water solubility, and are known to alter the wettability of porous media.  These properties often work together to make traditional remedial techniques inefficient or completely ineffective.  The properties themselves are determined by the chemical composition of the tars, which in turn, is impacted by the specific manufacturing process and the field conditions.  We have conducted thorough characterizations of a commercially available coal tar and nine field samples from two former carbureted water gas MGPs.  Clear differences are observed not only between the coal tar and carbureted water gas tars from different sites—most notably in the concentrations of phenolics and heterocyclic compounds—but also between samples collected at different locations within the same site.  Specifically, the molecular weight distribution shifts downward as the tar migrates from the source area while the ability of the tar to alter wettability increases.  These changes have significant implications for site assessment and remediation—the concentration of the carcinogenic, high molecular weight PAHs in the tar decreases, but at the same time the tar becomes more difficult to remove from the subsurface.  We hypothesize that the compositional changes are caused by some combination of changes in manufacturing processes and chromatographic separation of compounds in the subsurface, and that these changes cause either a relative increase in concentration, or a decreased stability of surface active compounds.

Ground-Penetrating Radar:  Enhanced 3D Graphics Using Low-Cost Visualization Software

Gary G. LaFrance, P.E., Civil Engineering Consultant, 5734 Meadowbrook Drive, Harrisburg, PA 17112-3137, USA, Tel: 717-657-2520, Fax: 717-657-2520, Email:  g.g.lafrance@att.net

This paper is a “How To” for using low-cost visualization software, such as Slicer Dicer^TM, for developing enhanced, three dimensional (3D) image blocks from ground-penetrating radar (GPR) profiles.  The term “enhanced” means the process of creating additional profiles from adjacent lines by inverse distance weighting (IDW). Environmental scientists often employ GPR for locating targets such as underground storage tanks, utility lines, geologic subsurface features, and certain contaminant plumes like DNAPLs.  GPR profiles are routinely acquired in the field in two dimensions (2D).  3D image blocks can be useful in identifying trends and features not readily apparent in 2D.  The GPR equipment manufacturers have no low-cost 3D visualization software for GPR data gathered with 50 MHz to 900 MHz antennas, the frequency range of most interest to environmental scientists.  Seismic reflection 3D software used in the oil and gas industry can be adapted for GPR use, but at a high cost.  A practical, cost-effective solution for GPR 3D graphics is to transform the profile data into a format which can be used by Slicer Dicer^TM  and other low-cost 3D visualization software.  A custom, batch-processing program, similar to the author’s POST_P^TM software , is needed to truncate the profiles to a common length, to reverse the direction of specified profiles, and to create additional profiles by IDW.  The new set of profiles is then viewed individually by 2D GPR software and either exported or screen captured to one of the many raster formats supported by Slicer Dicer^TM.   The Slicer Dicer^TM  software has a full complement of 3D tools, including managing colors, rotating images, and creating slices, cutout blocks, and fence diagrams.  The final 3D visual presentation can be printed for inclusion in a report.  A case history involving an investigation of underground tanks is presented.  Three levels of enhancement are displayed for comparison:  (a)  no enhancement;  (b)  mid-point averaging of adjacent profiles; and  (c)  quarter-point profiles developed by IDW.  The transparency mode of  Slicer Dicer^TM is also illustrated.

A Comparison of Three Soil Characterization Methods on a Soil Formed in Sandy Glacial Outwash

Michael W. Morris, Jacobs Engineering, 6 Otis Park Drive, Bourne, MA 02532, Tel: (508) 743-0214, ext. 232, Fax: (508) 743-9177, Email: mike.morris@jacobs.com
Aimee Comeau, ECC, PB 519 Gaffney Road, Otis ANGB, MA 02542, Tel: (508) 563-9767, ext. 133, Fax (508) 563-7659, Email: acomeau@ecc.net
John T. Ammons, Biosystems Engineering and Soil Science, 2505 E.J. Chapman Drive, University of Tennessee, Knoxville, TN 37996-4531, Tel: (865) 974-8804, Fax: (865) 974-4514, Email: ammonst@utk.edu
Ryan Blair, Biosystems Engineering and Soil Science, 2505 E.J. Chapman Drive, University of Tennessee, Knoxville, TN 37996-4531, Tel: (865) 974-8804, Fax: (865) 974-4514

 A field scale test was performed to evaluate three different soil sampling approaches.  These included a USDA approach, a multi-increment approach, and a 5-point composite approach.  A 484 ft² plot in an upland outwash plain in Falmouth, Massachusetts was subjected to these three soil characterization methods.  The USDA approach involved the excavation of a soil pit or pedon with soils described according to the methods outlined in the Soil Survey Manual.  Natural soil horizons were identified and samples were collected to a depth of 4 ft.  For the multi-increment samples, a 30-point grid was installed and samples were collected using a 1 in core auger.  For the 5-point composite, a five-point grid was installed within the plot and samples were collected with a 2.5 in bucket auger.  Both the multi-increment and the 5-point composite samples were taken at arbitrary depths of 0-3 in, 3-6 in, 9-12 in, 21-24 in, and 33-36 in.  All samples were subjected to particle size and organic carbon analyses.  The upland soil shows the effects of podzolization with some translocation of organic matter with depth in the pedon.  The particle size analysis of the pedon confirms a sandy glacial outwash with a thin layer of loess in the upper horizons.  The particle size analysis also shows a clear pattern of decreasing silt content with depth in the pedon.  The organic carbon analysis shows both compositing approaches have greater organic carbon contents at depth compared to the soil pedon.  The compositing approaches also show higher silt contents with depth compared to the soil pedon.  The enrichment of organic carbon and silt in the lower samples may indicate a mixing of surface materials with depth for both composite methods. 

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