Timothy P. Ahrens, AMEC Earth and Environmental, Inc, 155 Erie Blvd., Schenectady, NY 12305, Tel: 518-372-0905, Fax: 518-372-1042, Email: tim.ahrens@amec.com
Jeffrey W. LaRock, AMEC Earth and Environmental, Inc, 155 Erie Blvd., Schenectady, NY 12305, Tel: 518-372-0905, Fax: 518-372-1042, Email: jeffrey.larock@amec.com
Paul J. Kurzanski, CSX Transportation, Inc, 500 Water St. J-275, Jacksonville, FL 32202, Tel: 904-359-3101, Fax: 904-245-2826

On December 23, 2001 a freight train derailed approximately 150 feet from the Genesee River in Rochester, New York. As a result of this 27-car derailment, approximately 14,000 gallons of acetone and 16,000 gallons of methylene chloride were released into the environment. To address the release of acetone and methylene chloride, several phases of remedial activities were conducted at the Site beginning in December of 2001. Initial activities included delineation of the spill and monitoring of the Genesee River to assess water quality. These investigations indicated that elevated concentrations of methylene chloride and acetone were present in the river sediment and that a plume was directly east of the shoreline extending to the center of the channel. Bioassay studies from sediment collected in the channel indicated that growth and survival of invertebrate organisms in the river were not adversely affected by the concentrations of methylene chloride found in the sediments. Several river sediment-sampling events confirmed that the plume was stationary, but natural attenuation of the plume appeared to be limited.  The impacted sediments were located within the Navigable Channel limits and state regulators insisted that bioassay studies and plume monitoring events were not sufficient.

This paper will discuss how dredging utilizing an environmental bucket and dredge cell approach proved to be an effective technology for removing a majority of impacted sediments while protecting the environment and community along with maintaining the river’s navigability. Through the use of GPS technology dredging was conducted with accuracy and precision that increased optimization.  Environmental parameters such as turbidity and chemical monitoring verified the effectiveness of the measures taken to protect the river. Implementation of a Community Air Monitoring Plan (CAMP) ensured protection of the surrounding communities.  

Heat Flow and Desaturation in Large-Scale Experiments of Thermal Remediation of DNAPL Sources in Aquifers

Ralph S. Baker, TerraTherm, Inc., 356 Broad Street, Fitchburg, MA 01420, Tel: 978-343-0300, Fax: 978-343-2727, Email: rbaker@terratherm.com
Uwe Hiester, University of Stuttgart, Research Facility for Subsurface Remediation (VEGAS), Pfaffenwaldring 61, D-70550 Stuttgart, Germany, Tel: 49(0)711-685-4745, Fax: 49(0)711-685-7020, Email: uwe.hiester@iws.uni-stuttgart.de
Gorm Heron, TerraTherm, Inc., 10554 Round Mountain Road, Bakersfield, CA 93308, Tel. and Fax: (661) 387-0610, Email: gheron@terratherm.com
John C. LaChance, TerraTherm, Inc., 356 Broad Street, Fitchburg, MA 01420, Tel: 978-343-0300, Fax: 978-343-2727, Email: jlachance@terratherm.com
Myron Kuhlman, MK Tech Solutions, Inc., 12843 Covey Lane, Houston, TX 77099, Tel: 281-564-8851, Fax: 281-564-8821, Email: mikuhlman@sbcglobal.net
Arne M. Färber, University of Stuttgart, Research Facility for Subsurface Remediation (VEGAS), Pfaffenwaldring 61, D-70550 Stuttgart, Germany, Tel: 49(0)711-685-4720, Fax: 49(0)711-685-7020, Email: arne.faerber@iws.uni-stuttgart.de
Hans-Peter Koschitzky, University of Stuttgart, Research Facility for Subsurface Remediation (VEGAS), Pfaffenwaldring 61, D-70550 Stuttgart, Germany, Tel: 49(0)711-685-4717, Fax: 49(0)711-685-7020, Email: hans-peter.koschitzky@iws.uni-stuttgart.de
Oliver Trötschler, University of Stuttgart, Research Facility for Subsurface Remediation (VEGAS), Pfaffenwaldring 61, D-70550 Stuttgart, Germany, Tel: 49(0)711-685-7021, Fax: 49(0)711-685-7020, Email: oliver.troetschler@iws.uni-stuttgart.de

In-situ thermal remediation (ISTR) technologies are receiving increasing attention for remediation of dense non-aqueous phase liquid (DNAPL) source zones in soil and groundwater.  A clear understanding of the mechanisms of ISTR is crucial in selection of appropriate sites and effective ISTR technologies for DNAPL source zone remediation.  Large-scale physical model experiments have proven indispensable for incorporating thermal interactions between soil layers of different permeability.  In this Strategic Environmental Research and Development Program (SERDP)-funded project, large-scale physical models are being used to address several essential research questions, including: (a) the relative significance of various contaminant removal mechanisms below the water table (e.g., steam stripping, volatilization, in-situ destruction); (b) the percentage of DNAPL source removal and accompanying change in water saturation at various treatment temperatures/durations through boiling; and (c) the potential for DNAPL mobilization through volatilization and recondensation and/or pool mobilization outside the target treatment zone during heating.  Thermal conductive heating (TCH) is an ISTR method that takes advantage of the invariance of thermal conductivity across a wide range of soil types to effect treatment of DNAPL in lower-permeability and heterogeneous formations.  TCH can complement steam-enhanced extraction, which is generally more applicable to higher-permeability formations.  TCH accompanied by vacuum extraction is being employed in large-scale (containers 3 x 6 x 4.5m, and 6 x 6 x 4.5m) [width, length, height] controlled-release, closed mass balance experiments with geologically-relevant layering.  In parallel, non-isothermal numerical modeling issimulating the controlling mechanisms and processes of the experiments.  This research will answer key questions associated with the effectiveness of ISTR and lead to improvements in screening, selection, evaluation and design of field-scale ISTR systems.

DNAPL Remediation at Camp Lejeune using Soil Mixing with ZVI-Clay Injection

Christopher Bozzini, P.E, CH2M HILL, 4824 Parkway Plaza Blvd., Suite 200, Charlotte, NC 28217, Tel: 704-329-0072, Fax: 678-579-8119, Email: Chris.bozzini@ch2m.com
Tom Simpkin, Ph.D., P.E., CH2M HILL, 100 Inverness Terrace East, Englewood, CO  80112-5304, Tel: 303-771-0900, Fax: 720-286-9884, Email: Tom.simpkin@ch2m.com
Daniel Hood, NAVFAC Atlantic, NC/Caribbean IPT, EV Business Line, 6506 Hampton Blvd., Norfolk, VA 23508, Tel: 757-322-4630, Fax: 757-322-4805, Email: Daniel.r.hood@navy.mil
Bob Lowder, Camp Lejeune EMD, Commanding General, EMD/EQB, Marine Corps Base, Camp Lejeune, NC 28542, Tel: 910-451-9607, Fax: 910-451-5997, Email: Robert.a.lowder@usmc.mil

Site 88 at Marine Corps Base Camp Lejeune, NC is the former Base dry cleaners.  The dry cleaner was about 60 years old and located in a densely developed area.  Historical activities resulted in a release of solvents, especially tetrachloroethene (PCE). CH2M HILL conducted the delineation of the source area using multimedia sampling and AGVIQ-CH2M HILL JV1 completed the remediation.  The volume of contaminated soil was about 7,000 cubic yards, containing an estimated 14 tons (~2,100 gallons) of PCE.  Prior to implementation, groundwater concentrations of PCE and daughter products totaled 145,000 mg/L and product was observed in several monitoring wells.  Soil mixing with zero valent iron (ZVI) and clay addition was the selected for remediation because the patented technology is robust, can overcome subsurface heterogeneity, and reduces the soil conductivity thus reducing contaminant mobility. The ZVI-clay and soil mixture was injected using a 10-ft auger mounted on a crane to mix 146 overlapping columns to a depth of 20 feet below ground surface.  After preparing the site by removing all monitoring wells, subsurface utilities and the former building slab, treatment occurred over 17 days with 200 tons of ZVI and 100 tons of bentonite mixed into the soil.  Post-treatment monitoring of the site has included soil, groundwater, soil vapor sampling and analyses, and qualitative analysis using membrane interface probe (MIP) technology. The remedial action has worked well as PCE concentrations in soil have been reduced from 1,100 mg/kg to less than 1 mg/kg across most of the treatment area.  Soil gas results have shown 99% reduction in PCE.    In addition the hydraulic conductivity of the soil has been reduced by an order of magnitude, thus reducing future contaminant migration.  After treatment was completed, the site was stabilized using concrete and a parking lot has been constructed over the entire area.

Innovative Application of Full Scale Six-Phase Heating for DNAPL Source Removal

David A. Cacciatore, Shaw Environmental, Inc., 4005 Port Chicago Highway, Concord, CA, 94520, Tel: 925-288-2299, Fax: 925-288-0888, Email: david.cacciatore@shawgrp.com
John McGuire, Shaw Environmental, Inc., 4005 Port Chicago Highway, Concord, CA, 94520, Tel: 925-288-2220, Fax: 925-288-0888, Email: john.mcguire@shawgrp.com
Glenna M. Clark, Department of the Navy, Base Realignment and Closure, Program Management Office West, 1455 Frazee Road, Suite 900, San Diego, CA 92108, Tel: 619-532-0951, Fax: 619-532-0940, Email: glenna.clark@navy.mil

Full scale six-phase heating (SPH) was performed at IR Site 5, Alameda Point for DNAPL source removal within the 10,000 µg/L total contaminants of concern (COCs) contour of Plume 5-1, an area of roughly 15,000 ft², to a maximum depth of 20 ft bgs.  The principal COCs were 1,1-DCA, 1,1-DCE, and 1,1,1-TCA.

The successful full scale application of SPH required technology innovation.  Five standard SPH cells, each six electrodes arranged in a hexagonal pattern with a neutral electrode at its center, were used to heat the entire plume.  Novel parallel operation of adjacent SPH cells, with appropriate electrode phasing, was required for interstitial area heating through electrical cross talk.  Innovative multiple-member electrodes were utilized to achieve increased application rates and driven sheet-pile electrode members were cost effectively installed to provide greater surface area than the standard drilled electrodes.

The full scale SPH application at Plume 5-1 began on July 8, 2004 and was terminated November 5, 2004.  The average plume temperature increased from an initial value of 22ºC to 92ºC within a 12-week period, and was maintained for 3 weeks prior to termination.  Contour mapping of the temperature data confirm that all plume areas were heated to at least 90ºC.  Daily mass removal rates, estimated from continuous and periodic vapor sampling, show that more than 3,000 pounds of VOCs were recovered.  Groundwater concentrations were reduced from an average initial total COCs concentration of 54,000 micrograms per liter (µg/L) to less than 100 µg/L at the end of the active heating period, or a reduction of 99.8 percent.  Follow-on sampling in March 2005 showed minimal rebound.

The full scale utilization of SPH at Plume 5-1 was the largest application of SPH to date, and proves that the technology can be scaled up for balanced, effective heating of a large area.  In February of 2006 we began the installation of a SPH system for source removal at Plume 5-3, an area of roughly 40,000 ft², to 20 ft bgs.  Operations should begin in May 2006.  

The Evaluation of Extraction and Cleanup Methods for the Determination of PCB Aroclors in Caulking and Sealing Material

Ann C. Casey, Northeast Analytical, Inc., 2190 Technology Dr., Schenectady, NY 12308, Tel: 518-346-4592, Fax: 518-381-6055, Email: annc@nealab.com
Robert E. Wagner, Northeast Analytical, Inc., 2190 Technology Dr., Schenectady, NY 12308, Tel: 518-346-4592, Fax: 518-381-6055
Thomas E. Herold, Northeast Analytical, Inc., 2190 Technology Dr., Schenectady, NY 12308, Tel: 518-346-4592, Fax: 518-381-6055
Mike Glenn, Northeast Analytical, Inc., 2190 Technology Dr., Schenectady, NY 12308, Tel: 518-346-4592, Fax: 518-381-6055

Buildings that were built and/or refurbished before 1977 may well have caulking used to seal masonry joints and windows that contain PCB Aroclor 1254 and/or 1260. The Aroclors were used as a plasticzier and were added to the material to ease application and improve resiliency.  The caulking material has been mainly used when there are dissimilar materials, like brick next to concrete, metal window framings, and roofing joints. 

Several investigations took place in the 1990’s in Germany, Sweden, and Finland.  The studies established relationships between PCBs in caulking and levels in indoor air as well as in soil around the foundations of buildings containing these materials (Balfanz et al. 1993; Burkhardt et al. 1990; Pyy and Lyly 1998).  This same relationship has been demonstrated here in the US by R.F. Herrick (2004) and his team at the Department of Environmental Health, Harvard School of Public Health, Boston, MA. This study surveyed the PCB content of caulking from 24 buildings in the Boston Area.  Of the 24 buildings sampled, 13 contained caulking with detectable PCBs. Of these, 8 buildings contained caulking that exceeded the USEPA’s hazardous waste standard of 50 ppm. The laboratory identified the PCB as Aroclor 1254 and Aroclor 1260.

Commercial laboratories, like NEA, are put to the test when analyzing caulk matrix.  Caulking material itself is made of several different polymer components, many of which can interfere with the extraction and detection of PCBs.  Typically, results are requested on a quick turnaround basis.  So, the challenge is to optimize extraction and cleanup methods for this matrix.  NEA has evaluated 4 extraction methods for processing caulk. The extraction methods are soxhlet, sonication, accelerated solvent extraction (ASE) and polytron homogenization. All extractions used 1:1 Hexane/Acetone.  Several cleanup methods were also employed on the sample extracts including: acid wash, Florisil slurry, Florisil columns, and ultrasonication.   NEA analyzed the samples by USEPA Method 8082 Aroclor analysis by GC/ECD.  We will present an optimized method that is rugged, fast, cost effective, and has reproducible results.

PAH Bioremediation

Michael L. Cook, President, CJH Environmental, Inc., Sharon, MA 02067, Tel: 781-341-2833

The property at 248 Lynn Road in Brockton, MA consists of a one family ranch house constructed using a slab-on-grade construction technique. Heating of the home was provided through a central heating unit located in the kitchen using an oil fired forced hot air ducting arrangement. The fuel oil tank was located outside the structure along the south wall of the home inside a small wooden shed attached to the house. Fuel was supplied to the heating unit via a small diameter copper tube placed beneath the floor slab. In late 1992/early 1993 it became evident that something was amiss with the fuel distribution system to the heater. A subsurface investigation report dated April 26, 1993 indicated that the fuel line from the AST to the heater had failed and that a significant, but unknown, quantity of fuel oil had been released to the subsurface soils beneath the floor slab. The extent of contamination appeared to be well defined. Several attempts were made to determine whether fuel oil had migrated outside the perimeter walls of the slab foundation with indications being that it had not done so. All the contaminants appeared to be located directly beneath the floor slab in the kitchen area, with some spread under the adjacent bedroom and living room areas. After several years of legal wrangling, an agreement was reached among the various potentially responsible parties to allow remediation to move forward. A release Abatement Measures Plan was prepared dated March 21, 2001 for bioremediation (PAH) of the property after several false starts negotiating a suitable contract agreement among the parties. Approximately one more year passed before all the appropriate approvals and contracts had been signed and remediation began.

This presentation chronicles the efforts made to remediate this property to a successful conclusion.

A Case Study of Innovative Organoclay Remedial Technology at a Former Railroad Creosote Treating Site

Jerry Darlington, CETCO, 1500 W. Shure Dr., Arlington Heights, IL 60004 Tel.: 847-818-7214, Fax: 847-392-0465, E-mail: jerry.darlington@cetco.com
Jim Olsta, CETCO, 1500 W. Shure Dr., Arlington Heights, IL 60004 Tel.: 847-818-7912, Fax: 847-818-7294, E-mail: jim.olsta@cetco.com

The concept of permeable reactive barriers (PRB) had generated great interest in the field of groundwater remediation in the last few years.  Organoclay media has become an option as the reactive material for this type of application due to its high adsorption capacity, high removal efficiency on a variety of organic species, cost and availability.  The case study described below illustrated the use of organoclay media in construction of a permeable reactive barrier, as well as a reactive capping mat, to treat contaminated groundwater.

The groundwater at a former creosote railroad tie treating site was contaminated by NAPL (non-aqueous phase liquid).  The contaminated groundwater was a threat to the nearby fresh water bay when NAPL and soluble organics were found seeping into the bay.  The solution to stop this pollution spreading through the bay and into Lake Michigan was to install an organoclay reactive capping mat along the affected stretch of beach and a passive reactive wall behind the reactive capping mat.

Rolls of organoclay reactive capping mat were laid along a 5 m x 80 m stretch of beach.  The reactive capping mat was covered with 15 cm of 18 mm stone and then 60 cm of riprap.  As soon as the reactive capping mat was placed the sheen that had been seeping into the bay dissipated.

Bulk organoclay was mixed with 3 parts 6 mm gravel in a stockpile.  Approximately 5 m behind the reactive capping mat, a continuous trenching machine placed the organoclay-gravel mix in a 45 cm wide by 3 m deep by 80 m long trench.  

Achieving Quality Installations of Deep Permeable Reactive Barriers for Treatment of Chlorinated Solvent-Contaminated Groundwater

Stephen J. Druschel, PE, Senior Engineer, Golder Associates, Inc., 540 Commercial Street, Manchester, NH 03101, Tel: 603-668-0880, Email: sdruschel@Golder.com
Nancy E. Kinner, PhD, Professor, Department of Civil and Environmental Engineering, University of New Hampshire, 236 Environmental Technology Building, Durham, NH 03824-3591, Tel: 603-862-1422, Email: nancy.kinner@unh.edu

In situ, passive groundwater treatment for volatile organic compounds may be accomplished by installing a permeable reactive barrier (PRB) ahead of the contamination plume. Reactive media may be zero valent metal, microbially-enhancing organic substrate, or sorbent material such as activated carbon. PRB construction appears so simple: dig a deep trench and fill it with reactive media, stand back and let treatment happen. However, it is the construction beneath the groundwater surface that makes the details complex, such as maintaining trench support, keying into underlying rock or preventing holes (“windows”) in the reactive media. Quality is achieved by maximizing treatment, while having a reliable, well-understood installation.  Simple in design, a PRB may be difficult to construct due to the constraints of working below the groundwater, particularly when depths totaling more than 30 feet are attempted. Meeting all goals of design will create a basis for trust between designers, constructors, owners, regulators and the community; stumbling through construction difficulty can destroy such trust. In this paper, construction techniques currently in use for PRB excavation and backfill are discussed and evaluated for potential implications in four PRB failure modes. Design and construction processes are assessed in a case study of a 400-foot long by 65-foot deep PRB installed for treatment of a large tetrachloroethene release in residual and lacustrine soils. A ten-step system is proposed to emphasize readiness and preparation during PRB installation as a method to achieve quality, gain trust and reduce costs.

Case Study - Innovative In-Situ Anaerobic Remediation to Treat Fuel-Oil Contamination

Alexander Easterday, ECC, 33 Boston Post Road, Suite 340, Marlborough, MA, 01752, Tel: 508-229-2270, Fax: 508-229-7737, Email: AEasterday@ecc.net
Robert Wasserman, ECC, 33 Boston Post Road, Suite 340, Marlborough, MA, 01752, Tel: 508-229-2270, Fax: 508-229-7737, Email: RWasserman@ecc.net
Curt Varner, TRC Environmental Corporation, 5540 Centerview Drive, Suite #100, Raleigh, NC, 27606, Tel: 919-256-6204, Fax: 919-828-1977, Email: CVarner@TRCSOLUTIONS.com
Eric C. Hince, Geovation, Inc., 468 Route 17A, Florida, NY, 10921, Tel: 845-651-4141, Fax: 845-651-0040, Email: eric@geovation.com
Antonio Leite, US Navy, Groton, CT, 06340, Tel: 860-625-7386, Email: antonio.leite@navy.mil

This case study details the application of an innovative, anaerobic in situ technology to remediate petroleum contamination associated with a former No. 2 fuel oil underground storage tank at a military housing residential annex in Groton, Connecticut.  The release site is located upgradient of a surface water receptor that serves as a secondary drinking water source for the City.  A remedial investigation was completed at the site to characterize the nature and extent of petroleum impacts, and several remedial alternatives were evaluated to treat hydrocarbon impacts to soil and groundwater.  Several applicable remedial alternatives were considered, including excavation, aerobic in situ technologies, anaerobic in situ technologies, and traditional engineered remedial alternatives (i.e., soil vapor extraction/air sparging).  While excavation was identified by regulators as the preferred remedial method, it was precluded from use given the site location, the prohibitive cost, and due to a large portion of the contaminant mass underlying the existing residential structure.  Therefore, an anaerobic in situ treatment technology (denitrification-based bioremediation [DBB]) was recommended and selected as the remedial approach at this site.  The acceptance of the DBB treatment technology by the regulators was the first application of this remedial technology in the State of Connecticut.  In Sept 2003, baseline sampling was performed to document pre-remedial conditions.  The nitrogen-based treatment solution was introduced to the subsurface through micro-wells and via passive diffusion gradients.  Periodic soil and groundwater sampling activities were performed to assess treatment efficacy with respect to contaminant concentrations, and demonstrated that DBB successfully reduced the contaminant mass underlying the site (i.e., 50-60 percent reductions in sorbed-phase concentrations) while mitigating additional impacts to groundwater.  The site-specific treatment program and post-treatment sampling activities were completed in July 2004.  Additional monitoring data and focused treatments were completed in 2005 and 2006 which will be presented in this poster.

Use of Electrical Imaging and Microscopy to Evaluate Distribution of Injected Nano-scale Zero Valent Iron

Dan Elliott, PhD, The Whitman Companies, Inc., 116 Tices Lane, Unit B-1, East Brunswick, New Jersey, Tel: 732-30909-5858, Fax: 732-30909-09466, Email: delliot@whitmanco.com
Edward Sullivan, P.G., The Whitman Companies, Inc., 116 Tices Lane, Unit B-1, East Brunswick, New Jersey, Tel: 732-30909-5858, Fax: 732-30909-09466, Email: esullivan@whitmanco.com
Christopher DelMonico, The Whitman Companies, Inc., 116 Tices Lane, Unit B-1, East Brunswick, New Jersey, Tel: 732-30909-5858, Fax: 732-30909-09466, Email: cdelmonico@whitmanco.com
Eric C. Hince; Geovation Consultants, Inc., 468 Route 17A, Florida, NY 10921, Tel: 845-651-4141, Fax: 845-651-0040, Email: echince@geovation.com  

A pilot study was conducted using nano-scale zero valent iron (nZVI) and an emulsified soy oil product to promote dual abiotic and biotic degradation of TCE at a site in New Jersey.  The nZVI and emulsified oil injections targeted a low permeability silt unit where most of the contaminant mass was bound.  A sand aquifer overlies the silt unit.  Pneumatic and hydraulic fracturing techniques were used to enhance the distribution of the injected amendments.  A comparison of pre and post-injection Electrical Imaging (EI) surveys and ground water microscopy samples were used to evaluate the distribution of the nZVI particles achieved by the fracturing techniques.

The conductivity of saturated earth materials is dominated by the porosity and pore moisture chemistry.  A decrease in the resistivity would be consistent with an increase in the conductivity of the saturating fluid due to the iron in the injected fluid.  An increase in resistivity would be consistent with a decrease in the conductivity of the saturating fluid possibly due to the presence of high concentrations of chlorinated VOCs.  The penetration depth of the EI survey was not sufficient to evaluate resistivity changes at the depth of injection.  However, an increase in resistivity was noted in the sand aquifer interval just above the silt unit.  Post-injection sampling data also showed a significant increase in TCE concentrations in this interval.  This indicates that the injection techniques likely mobilized TCE mass upward from the silt unit into the sand aquifer.

The nZVI particles were observed via transmitted light microscopy and imaged with a CCD camera as angular, opaque objects ranging in size from less than 1 um to approximately 5 µm indicating that significant aggregation has occurred.  nZVI particles were detected in samples collected from monitoring wells in the silt unit and the overlying sand unit at distances up to 25 feet from the injection points.   This indicates that both of the fracturing techniques were successful in distributing the nZVI a significant distance from the injection points.  Computer image analysis software running a particle-counting subroutine was utilized to count the number of nZVI particles in each sample.  In general, higher nZVI particle counts were seen in the silt unit wells.  No particles resembling nZVI were observed in the wells sampled prior to the nZVI injections to determine baseline conditions.  To our knowledge, this is the first time these relatively inexpensive imaging and microscopic techniques were applied to the detection of injected nZVI in the field

Combining Technologies for Source Area and Downgradient Contaminated Groundwater Remediation Using AS/SVE and iSOC Technology

Craig Ellis, Environmental Compliance Services, Inc., 607 North Main Street, Suite 11, Wakefield MA 01880, Tel: 781-246-8897, Fax: 781-246-8950, cellis@ecsconsult.com
Jamie Smith, Environmental Compliance Services, Inc., 607 North Main Street, Suite 11, Wakefield MA 01880, Tel: 781-246-8897, Fax: 781-246-8950, jsmith@ecsconsult.com
James F. Begley, MT Environmental Restoration, 24 Bay View Avenue, Plymouth, MA 02360, Tel: 508-732-0121, Fax: 508-732-0122, jbegley@cape.com

Remediation of groundwater contaminated by historical releases of gasoline at a Massachusetts site required a combination of technologies to address high concentration source area soil and groundwater contamination as well as a plume of contaminated groundwater that had migrated from the source area. The remedial action plan included source area air sparging and soil vapor extraction combined with enhanced monitored natural attenuation using the in-situ Submerged Oxygen Curtain (iSOC) System at a remote down gradient location. A case study of combined technologies implemented at the site will be presented that includes the basis for system design and the results of performance monitoring.

Modified Asphalt Alternative for Working Surfaces and Permanent Environmental Caps

Ronald L. Terrel, Terrel Research LLC, 9703 – 241^st Pl. SW, Edmonds, WA 98020 , Tel. 206-542-9223, Fax 206-542-6159 Email: rterrel@comcast.net
Jerry A. Thayer, Wilder Construction Company, 1525 E. Marine View Dr., Everett, WA 98201, Tel. 425- 551-3100, Fax: 425-51-3116, Email: jerrytha@wilderconstruction.com
W. Randall Garrett, Wilder Construction Company, 896 Quinnipaic Ave. #9 New Haven, CT 06513, Tel: 203-468-0087, Fax: 203-468-0079, Email: W_R_G@sbcglobal.net

Traditional environmental covers and caps have typically been designed and constructed as a series of layered clay and plastic, often several feet thick.  As such, these structures are usually off limits to general use, and especially to heavy duty applications such as parking or laydown areas for industrial sites. 

Beginning in 1989, Wilder Construction Company developed a new concept for caps that can also be used for working surfaces such as sediment handling and storage.  The first project was for ash storage from an industrial furnace and served both as a cap and working surface for additional storage, and later other industrial uses.  Following 10 years of use, and still retaining its initial integrity and low permeability (k < 1 x 10^-8 cm/sec), the system, (called MatCon, for Modified Asphalt Technology for Containment) was evaluated by the USEPA SITE Program and found to be an acceptable alternative.  The MatCon systems have been accepted by State regulatory agencies, and have been successfully installed throughout the U.S. since 1999.  These applications have ranged from landfill covers, hazardous waste sites, sediment storage sites, and others.

MatCon utilizes construction technology from the highway industry, but has optimized the materials and design to provide exceptional low permeability and long-term durability.  The 4-in thick layer is composed of highly modified asphalt, high quality aggregates, other additives, and is constructed following a detailed quality control program.  Extensive evaluation and testing of constructed  projects has shown the material to have long projected life (17 years to date, and projected 30+ years) with minimal maintenance, yet permitting extensive use of the surface with little restriction.  For extremely aggressive use, a flexible and tough surface option (called Armor Top) can be added to provide assurance of integrity.  Armor Top is made by injecting a flexible open-graded MatCon with a proprietary super-hard grout so that it combines the abrasion resistance of concrete with the resilience of asphalt pavement.

A Pilot Study using a Chemical Oxidant and Surfactant to Remediate Petroleum Hydrocarbons at an Active Gasoline Station

Joseph Hayes, P.G., ECS, 65 Millet Street Richmond, VT  05477, Tel: 802-434-4500, Email:  jhayes@ecsconsult.com
Maureen Dooley, Regenesis, 19 Belmont Road, Wakefield, MA 01880, Tel: 781-245-1320, Email: mdooley@regenesis.com          

This presentation will discuss the results of a pilot study involving bench-scale testing and a field injection program using a chemical oxidant, REGENOX^TM and a surfactant, BIOSOLVE® at an active gasoline station in Vermont.  The objective of this pilot study was to field test the application of combining a chemical oxidant and surfactant to remediate residual gasoline related VOC contamination for possible full scale application to meet site closure criteria.   

The pilot test was designed to address residual dissolved phase gasoline related VOC concentrations remaining in the subsurface near an existing gasoline dispenser island that were not completely remediated under a under Vermont’s Pay for Performance Program.  The REGENOX^TM product uses a solid alkaline oxidant that is activated through the action of a proprietary dual catalytic system.  BIOSOLVE® is a water based biodegradable non-ionic surfactant that was specifically engineered as a remediation product for a wide range of petroleum hydrocarbons. 

The results of bench-scale testing indicated that there was little reactivity between the REGENOX^TM and BIOSOLVE®, and that field testing was warranted to further evaluate this remedial approach. The purpose of including a surfactant in the injection program is to solubilize the adsorbed-phase contaminants making them more amenable to chemical oxidation.

The aqueous solution of oxidant and surfactant will be injected using conventional direct push drilling equipment and an injection pump over a depth interval of approximately 5 to 15 feet below ground surface.  Prior to and following injection, a monitoring program will be instituted to evaluate the effectiveness of the surfactant and oxidant mixture at reducing VOCs in the test area.  

Combined Excavation and In-Situ Oxidation via KMnO₄ Injection

Patrick Hicks, ATC Associates, Inc, 2725 E. Millbrook Rd., Suite 121, Raleigh, NC, 27604, Tel: 919-871-0999, Fax: 919-871-0335, Email: hicks93@atc-enviro.com

Remediation usually requires the combined effects of different remediation technologies each playing a key role in focusing on the target media.  The combined effects are required to achieve closure goals or remove the source of contamination.

The synergistic effect of combined soil excavation and oxidant (KMnO₄) injection to treat soil and groundwater impacted with PCE was demonstrated at a former dry cleaner site in Indiana.  The source area soils were identified during a phased site investigation.  The conceptual site model suggested that PCE was released from a section of broken drain line that ran from the former dry cleaner and tied into the sanitary sewer system.  A corresponding dissolved phase plume was identified in the groundwater at this location and extending down gradient of the release.

Site re-development activities drove the schedule on this project, and minimized access to the plume.  Traditional excavation was used to remove approximately 840 tons of PCE impacted soils in the source area.  In conjunction with source soil removal, a series of KMnO₄ injection wells were installed to address the dissolved phase PCE near and down gradient of the source area.

The rapid removal of the source area soils has allowed the KMnO₄ injections to more effectively address dissolved contaminants without dealing with a large adsorbed phase source.  Groundwater concentrations in the area immediately down gradient of the soil source area that were originally as high as 9,300 parts per billion (ppb) have decreased to below 200 ppb.  Many monitoring wells in the area immediately down gradient of the former soil source area now have dissolved concentrations below the detection limit.

Combined Chemical Oxidation and Volatilization Enhances Guaranteed Remediation Performance

Patrick Hicks, ATC Associates, Inc, 2725 E. Millbrook Rd., Suite 121, Raleigh, NC, 27604, Tel: 919 871 0999, Fax: 919 871 0335, Email: hicks93@atc-enviro.com

A guaranteed fixed price remediation project in Salt Lake City, UT was initiated in 2003.  The site is a former dry cleaner facility, and is regulated under the Utah Voluntary Cleanup Program (UVCP).  A cleaning solvent release resulted in a dissolved plume of Tetrachloroethene (PCE), Trichloroethene (TCE) cis 1,2-Dichloroethene (cisDCE), trans 1,2-Dichloroethene (trans DCE), and Vinyl chloride (VC) below the facility that migrated down gradient across the property.  Buildings and traffic at the location restricts access to portions of the dissolved plume, and site geology and geochemistry is relatively complex.  Thus, the project required a remediation approach with sufficient operational flexibility to compensate for the technical challenges presented by site conditions.

A combined approach using permanganate as a chemical oxidant, and in well volatilization (IWV) and traditional soil vapor extraction (SVE) was implemented at the site.  The IWV and SVE components were installed and began operation in March 2004.  The chemical oxidation process began on a pilot test scale in April 2004, and was implemented on a full-scale basis in August 2004.  The enhanced distribution of the permanganate by the IWV system was considered to be a critical design component given the complex lithology at this site.

The chemical oxidant (3.5% sodium permanganate) injections were limited to 3,200 gallons in April and 5,100 gallons in August 2004.  The IWV and SVE systems were operated until January 2005, at which time active remediation was suspended.  Based on May 2005 groundwater monitoring, concentrations of dissolved solvent constituents have been reduced by 90% or more from baseline concentrations in portions of the plume, and have been completely eliminated in some monitoring wells.  Negotiations with the UVCP regarding risk-based closure options are ongoing, and it is anticipated that closure will be obtained in the near future.

Permeable Sorption Barriers for Groundwater Protection Includes Organoclay, Clay, Bentonite Geotechnical Fabric and Anaerobic Treatment of Pesticide Contaminated Soils

Eric C. Hince, P.G., Geovation Consultants, Inc., 468 Route 17A, Florida, NY, 10021,Tel: 845-651-4141, Fax: 845-651-0040, Email: echince@geovation.com 
George Alther, Biomin, Inc., P. O. Box 20028, Ferndale, MI 48220, Tel: 248-544-2552, Fax: 248-544-3733, Email: Biomin@aol.com

Approximately 29,000 tons of soils contaminated with DDT and toxaphene were treated with proprietary amendments designed to facilitate a combination of anaerobic reductive dechlorination and anaerobic oxidation biodegradation processes.  After treatment, the soils were placed in a “biocell” designed for long-term containment and passive anaerobic bioremediation.  Permeable sorption barriers were constructed as groundwater-protection components of the biocell. The lower barrier was constructed by amending native coarse-sand and gravel soils with a 3:1 mixture (weight/weight) comprised of 116,000 lbs. of montmorillonite and 40,000 lbs. of a proprietary “organoclay” specialty filtration media (Biomin, Inc.).  This organoclay had been tested for its effectiveness to fixate such pesticides as alachlor, diazinon, metolachlor, 2,4-D, trifuralin, 2,4,5-T, and others. The clay materials were mechanically incorporated into the upper six inches of native soils and compacted to achieve a permeability estimated to be on the order of from 1 x 10^-5 to 1x10^-6 cm/sec (substantially lower than estimated “native” permeability of about 1x10^-2 cm/sec).  The clay minerals within the sorption barrier provide a selective capacity to adsorb more than 2 x 10¹⁰ mg of pesticides, an amount 10 times greater than the total mass of pesticides present in the soils prior to treatment.  Based on calculations of estimated leak rates through the overlying geosynthetic clay liner (GCL), the clay-amended sorption barrier would provide protection for an estimated 7 x 10⁷ years against pesticides leaching at concentrations approaching their maximum solubility.

A Bentomat^TM SDN geosynthetic clay liner (GCL) was installed immediately above the clay-amended sorption barrier (CETCO Lining Technologies).  Bentomat^TM SDN consists of a layer of sodium bentonite between two sheets of non-woven geotextile fabric.  The GCL was installed immediately above the clay-organoclay sorption barrier, around the sides of the biocell and anchored into clean soil berms surrounding the biocell to provide further containment and long-term groundwater protection.  Aside from the obvious protective benefits provided for by the GCL, the primary function of the GCL is to slow the rate of fluid flow through the overlying peat-amended biofiltration layer and hence to greatly increase the residence time of pore-water fluids in the biofiltration layer.  The biofiltration layer is comprised of a mixture of >2,300 cubic yards of clean and low-pesticide-concentration soils (i.e., ± 0.5 - 10 mg/Kg) blended with >248,000 lbs. of aged peat.  The peat-amended soils comprising the biofiltration layer were processed in a power screen and emplaced on the surface of the GCL via a mechanical conveyor system.  The final installation of the biofiltration soil layer resulted in a ± one-foot thick lift immediately above the GCL.  The amount of aged peat incorporated into the biofiltration layer provides a selective capacity to adsorb more than 9 x 10¹⁰ mg of pesticides, approximately 90 times the total mass of pesticides present in the soils prior to treatment.  Based on calculations of estimated leak rates through the underlying GCL, the peat-amended biofiltration layer would provide protection for more than 2.5 x 10⁸ years against pesticides leaching to groundwater.  The combination of the clay-amended sorption barrier, Bentomat GCL and peat-amended biofiltration layer provide a total selective capacity to adsorb more than 1.25 x 10¹¹ mg of pesticides, (two orders of magnitude greater than the total mass of pesticides prior to treatment), and provide more than 3.5 x 10⁸ years protection against the leaching of pesticides to groundwater.

Providing Safe Drinking Water in Developing Countries

A. Jagadeesh, Centre for Energy and Sustainable Resources, R.M.K.Engineering College, Kavaraipettai 601 206, Tamil Nadu, India, Email: a_jagadeesh2@yahoo.com

Every 8 seconds, a child dies from water related disease around the globe. 50% of people in developing countries suffer from one or more water-related diseases. 80% of diseases in the developing countries are caused by contaminated water. Providing safe drinking water to the people has been a major challenge for Governments in developing countries. Conventional technologies used to disinfect water are: ozonation, chlorination and artificial UV radiation. These technologies require sophisticated equipment, are capital intensive and require skilled operators Boiling water requires about 1 kg of wood/liter of water which results in deforestation in developing countries. Also halazone or calcium hypochlorite tablets or solutions (sodium hypochlorite at 1 to 2 drops per liter) are used to disinfect drinking water. These methods are environmentally unsound or hygienically unsafe when performed by a layperson. Misuse of sodium hypochlorite solution poses a safety hazard. Impure water is the root cause for many diseases especially in developing countries. Millions of people become sick each year from drinking contaminated water. In many regions of the world, sunshine is abundantly available which can be effectively utilized to provide safe drinking water to the millions of people. A portable, low-cost, and low-maintenance solar disinfection unit to provide potable water has been designed and tested. The solar disinfection system has been tested with bore water, well as well as waste water. In 5 hours, the unit eradicated 3 log ₁₀ (99.99%) of bacteria contained in the water samples. The unit will provide about 6 liters of pure drinking water and larger units can be fabricated for providing safe drinking water at community level in developing countries. Eradication of coli forms from well water, bore water and waste water has been reported from test results. The results confirm that there is 4-log 10 reduction of coli forms in the waste water after solar disinfection. The experiments were conducted at Kavaraipettai, Tamil Nadu, India.Maximum temperature occurs around 1 pm. Though 6 bottles were used in the system (each of 1 liter capacity), larger units with up to 100 bottles can be designed. The unit destroyed 99.99% of bacterial coli forms both in well water and waste water samples in 5 hours.The innovative solar disinfection system has the advantages like: 1.The unit is portable, 2.It is cost-effective. It can be fabricated in South India for US$ 20.The unit incorporates the principle of reflection to increase solar intensity and has protection from wind which results in temperature rise inside the unit, 3.Larger units can be manufactured, 4. Used glass bottles withstand higher temperatures and are available in plenty each for 2 US cents in South India, 5. Since all the materials are available locally, the unit can be manufactured locally with local people. Temperatures above 30⁰c occur in south India for more than 10 months in a year and as such this innovative solar disinfection unit will be a boon in this region.

Small Column Experiment to Evaluate Compost Materials as Filter Media to Remove Colloidal Particles

Student Presenter

Aiman Q. Jaradat, Department of Civil and Environmental Engineering, Clarkson University, Potsdam, NY, 13699-5710, Tel: 315-268-4236,Email: jaradaaq@clarkson.edu
Thomas M. Holsen, Department of Civil and Environmental Engineering, W.J. Rowley Laboratory, Clarkson University, Potsdam, N.Y. 13699-5710, Tel: 315-268-3851, Fax: 315-268-7636, E-mail: holsen@clarkson.edu
Stefan J. Grimberg, Department of Civil and Environmental Engineering, 208 Rowley Laboratories, Clarkson University, Potsdam, NY 13699-5710, Tel: 315-268-6490, Fax: 315-268-7636, Email: grimberg@clarkson.edu

The treatment of low levels of PCB contamination in stormwater runoff or wastewater treatment effluent represents a significant cost to manufacturing and remediation facilities.  Current regulatory requirements require the use of best available technology (BAT) which consists of activated carbon followed by filtration.  Natural media filtration (NMR) represents a possibly significantly more economical process alternative to BAT.  The goal of this research was to determine filtration efficiencies of colloidal particle in NMR columns.          

In this study, mushroom and leaf compost materials were evaluated as a filter media to remove colloidal particles through a series of short pulse column experiments. The transport and deposition of model colloidal particles as a function of ionic strength and filter media were measured and evaluated by determining the first-order kinetic deposition rates.  Next to two natural filter media, experiments were conducted also using sand and granular activated carbon.

The results of this experiment demonstrate that the solution ionic strength influences the dynamics of colloidal deposition and transport in heterogeneous porous media. Deposition rates depend also on the filter media; highest deposition rates were observed for granular activated carbon followed by leaf compost, mushroom composts and lowest deposition rates were found for sand.  As expected, highest deposition rates were obtained at higher ionic strength.  The significant change in deposition rate as a function of both ionic strength and filter media could be explained by DLVO theory. Electrostatic surface interactions between colloidal particles and porous media were examined through electrophoretic mobility analysis as a function of ionic strength and solution pH. Results of these measurements demonstrate that increasing ionic strength and the presence of divalent Ca²⁺counterions lead to a decrease in electrophoretic mobility. This is consistent with predictions of the DLVO theory which predicts that at higher ionic strength and in the presence of divalent cations a compression of the double layer thickness occurs.  Under these conditions more colloidal particles can be expected to deposit on the surface of porous media.

Overall the experiments suggest that the NMF process may efficiently filter colloidal particles from surface waters. However, surface water chemistry will significantly affect the filtration efficiencies.

Retardation Properties of Clay Materials as Engineered Barriers in Repositories of High-level Waste

Věra Jedináková-Křížová, Institute of Chemical Technology, Technická 6, 166 28 Prague 6, Czech Republic, Email: Vera.Krizova@vscht.cz
Eduard Hanslík, T.G. Masaryk Water Research Institute, Podbabská 30, 160 62 Prague 6, Czech Republic
Hana Vinšová and Petr Večerník, Institute of Chemical Technology, Technická 6, 166 28 Prague 6, Czech Republic

Research on a bentonite-based engineered barrier designated for safe underground disposal of high-level radioactive waste is a special multidisciplinary issue. To obtain the findings enabling the design of such construction, all experimental tools and procedures available must be used. With respect to extremely long time requirements for rheological stability and safety of the whole designed system, the physical, chemical and geophysical results of research were cumulated for  physical modelling.

Bentonite was chosen as a buffer material surrounding the waste packages with spent fuel in deep waste repositories. The main merit of this material is very low permeability, high plasticity and its ability to seal the possible fractures by swelling in contact with water and therefore diffusion is the only possible mechanism of transport of radionuclides through the bentonite. Understanding of sorption and diffusion mechanism is essential in the assessment of radionuclide release through the bentonite buffer and backfill to the environment.

The effort has been done to interpret the sorption and diffusion data, particularly for radionuclides of cesium, stroncium and tritium and technecium as the representatives of multivalent elements. This information has important implications for modelling sorption and diffusion processes.

Experimental data allow a comparison of properties of bentonite before and after the load from the point of view of changes of its chemical and physico-chemical characteristics.

For performance and evaluation of experiments the through diffusion method has been applied and apparent diffusion coefficients (D_a) were evaluated by common analytical methods. In diffusion and sorption experiments the effect of particle mesh-size, different bulk densities and aerobic or anaerobic conditions on being in motion processes were studied, because oxidizing or reducing conditions influence chemical forms of multivalent elements.

The results obtained during sorption and diffusion study were applied as incoming parameters for the mathematical description of individual processes proceeded in the bentonite barrier. The essential aim of kinetic studies was to determine an optimum time to get the studied system into the equilibrium state, e.g. time when maximum values of distribution coefficients K_D and sorption yields are reached under given conditions.

Acknowledgement
This research was supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project MSM 6046137307, project of Radioactiove Waste Repository Authotity No 5SMN217 and project of Ministry of Industry and Trade No. MPO FI-IM/113.

Thermally Enhanced Soil Vapor Extraction: the HeatTrode^TM System

Kevin P. McGrath, CPG, Hydrogeologist, Earth Tech, Inc. 40 British-American Boulevard, Latham, NY 12110, Tel: 518-951-2200, Fax: 518-951-2300, Email: kevin.mcgrath@earthtech.com
Donald J. Geisel, E.E., Donald J. Geisel & Associates, Inc., 6 Jordan Court, Clifton Park, NY 12065, Tel/Fax: (518) 371-5029
Anne Lewis-Russ, Ph.D., Geochemistry, Earth Tech, Inc., 5575 DTC Parkway, Suite 200, Greenwood Village, CO 80111 Tel: 303-694-6660, Fax: 303-694-4410. Email: Anne.LewisRuss@earthtech.com

Thermally enhanced soil vapor extraction (TESVE) has been proven to be an effective remedial alternative for removing volatile organic compounds (VOCs) from unsaturated permeable soils.  Methods used for heating the subsurface soils include hot air injection, electricity, or steam. Numerous case studies of these applications are available demonstrating the viability of TESVE.

Under a research grant from the New York State Energy Research and Development Authority, Donald J. Geisel & Associates, Inc. (DGA) conducted a field pilot test of their proprietary HeatTrode^TM System at a site containing sequestered free product in the soils from grade to the seasonally low water table.  The free product included benzene, toluene, ethylbenzene, and xylene (BTEX) used in the manufacturing of phenolic compounds.  Accidental releases from raw product, intermediate process, and final product storage tanks had saturated the soils with BTEX and semivolatile organic compounds (SVOCs) phenolic.  A remedial investigation and feasibility study (RI/FS) of the site had determined that TESVE of the VOCs followed by bioventing of the SVOCs was the preferred remedial alternative for the site.

The HeatTrode^TM System is a hot water recirculatory system with collocated air extraction. Individual units can be adjusted and regulated to maintain both uniform heating throughout the remediation cell and balanced air withdrawal rates, effectively eliminating the formation of null zones (zones of no effect) within the area of treatment. The pilot test was conducted from March 2004 through September 2005. During the test near total removal of VOC contaminant mass was attained the soils while maintaining optimal conditions for reemergence of a microbial population for the eventual biodegradation of the residual phenolic compounds.

At the request of DGA, Earth Tech conducted an evaluation of the results of the pilot-test which, is reported in this case study.  Earth Tech concluded that the application of the HeatTrode^TM System is an effective and efficient remedial alternative.

Remediation of a 2,000-Gallon Fuel Oil Release at a Private Residence via Soil Excavation, Groundwater Treatment, and Enhanced Bioremediation

Anne McNeil, Senior Project Manager, Geoffrey A. Brown, Ph.D., Vice President, ENPRO Services, Inc., 12 Mulliken Way, Newburyport, MA 01950, Email: amcneil@enpro.com

A release of approximately 2,000 gallons of fuel oil occurred at a residential property as a result of a leaking, subfloor fuel oil feed line.  A neighbor discovered the release when he noticed oil breaking out of his lawn.  ENPRO was contracted through the homeowner’s insurance agency to cleanup the release.  To initiate the cleanup, ENPRO obtained verbal approval from the MADEP to conduct an Immediate Response Action (IRA) at the site.  In accordance with the IRA Plan, 400 tons of petroleum contaminated soil were excavated and recycled off site as asphalt batch material, 685 gallons of fuel oil were recovered from the subsurface and transported offsite for disposal, and soil and groundwater samples were collected to investigate the extent of contamination.  Additionally, because the site bordered a Town-owned wetland area, ENPRO performed the IRA under a Notice of Intent.

Following these initial IRA activities, site conditions indicated that fuel oil contamination remained at concentrations requiring continued, accelerated response actions.  ENPRO evaluated two remedial options for feasibility and cost effectiveness.  The remedial alternative selected to further reduce fuel oil concentrations in site soil and groundwater was a product recovery and groundwater treatment system utilizing enhanced bioremediation.  The system included an interceptor trench, a groundwater treatment system including an oil/water separator and bio-reactor, introduction of remedial additives, and re-injection of treated groundwater into the release area.  The system operated for two years.  During system operation and for one year after system shutdown, additional subsurface investigation was performed to document the effectiveness of the IRAs.

Based on the results of a Method 3 Risk Assessment, a condition of No Significant Risk was achieved for current and future site activities and uses.  As such, ENPRO submitted a Class A-2 Response Action Outcome Statement, documenting the permanent solution to the MADEP.

Chemical Contamination and its Effects on Physico-chemical Behavior of Bentonite and Kaolinite- a Comparison

K. Rajeswara Rao, Executive Engineer, 45-53-10, Abid Nagar, Visakhapatnam-530016, Andhra Pradesh, India, Email: drkrrao2003@yahoo.co.in

The present study investigates the effect of chemical contamination i.e. anionic (sulfate) contamination on the physico-chemical behavior of Kaolinite and Bentonite.   Study of the effect of chemical contamination on physico-chemical properties assumes a great significance in view of large number of toxic elements generated and released on to land by a number of industries.

The study brings out an opposite effect on expanding and non-expanding clay minerals.   Sulfate contamination is believed to mobilize an edge-edge flocculated fabric, which in turn contributed to increase in liquid limit.   However, the phenomenon was observed in case of bentonite at low concentration of contamination and such behavior was not observed in case of bentonite with high concentration of contamination or in case of kaolinite with different concentration.   The change in fabric on contamination is due to variation in attractive and repulsive forces at inter-particle level and this was confirmed through the study of fabric indirectly with the help of shrinkage limit and sediment volume of clay minerals.

PCB Remediation of a High-Hazard Dam

Frank Ricciardi, P.E., Weston & Sampson Engineers, Inc, 5 Centennial Drive, Peabody, MA, 01960, Tel: 978-532-1900, Fax: 978-977-0100, email: ricciarf@wseinc.com
Mark, Mitsch, P.E., Weston & Sampson Engineers, Inc, 5 Centennial Drive, Peabody, MA, 01960, Tel: 978-532-1900, Fax: 978-977-0100, email: mitschm@wseinc.com
Prasanta Bhunia, Ph.D., LSP, Weston & Sampson Engineers, Inc, 5 Centennial Drive, Peabody, MA, 01960, Tel: 978-532-1900, Fax: 978-977-0100, email: bhuniap@wseinc.com

The Fall of 2005 brought increased awareness of potentially hazardous and unsafe high-hazard dams in Massachusetts with a tense situation occurring in Taunton, Massachusetts. The Taunton dam came exceedingly close to breaching, potentially flooding numerous commercial areas and residential neighborhoods. Dam rehabilitation projects are very complicated and require painstaking care prior to implementing engineering controls and earthwork. However, when the dam structure itself is contaminated with concentrations of PCBs regulated by the Toxic Substance Control Act (TSCA) 40 CFR 761, the standard of care for precharacterization, excavation, confirmatory sampling, and disposal is increased dramatically. Prior to the rehabilitation of this High-Hazard dam in Worcester County, a full-scale remediation project was completed to remove PCB contaminated soil on the dam in accordance with Subparts N and O of the TSCA regulations. This paper will discuss the entire process of assessing the dam, developing the remediation strategy, implementing soil excavation activities while monitoring the structural integrity of the dam, and ensuring that PCB Remediation is in compliance with the TSCA regulations. We will also discuss the integration of the remediation work with the site civil work associated with the dam rehabilitation including:

• Reservoir dewatering and excavation for installation of intake structure

• Tailrace channel remediation and rehabilitation

• Compliance with TSCA, Massachusetts Contingency Plan (310 CMR 40.0000), Army Corps of Engineers 404 Clean Water Permit, and Massachusetts Wetland Regulations (310 CMR 10.00)

• Heavy equipment decontamination procedures, and

• Soil stockpile management

The project is currently ongoing and this paper will present results of the remediation effort.

High-Performance Attrition in a Wet-Mechanical Soil Washing Plant

Friedrich Schaaff, AKW Apparate + Verfahren GmbH, Dienhof 26, 92242 Hirschau, Germany, Tel: +49(0)9622 70 39 416 Fax: +49(0)9622 70 39 9416, Email: fschaaff@akwauv.com
Hilmar Tiefel, Dr. -Ing., AKW Apparate + Verfahren GmbH, Dienhof 26, 92242 Hirschau, Germany, Tel: +49(0)9622 70 39 410 Fax: +49(0)9622 70 39 9410, Email: htiefel@akwauv.com

Contaminated sand fractions in soils need special attention during soil washing. Due to the high specific surface area particles < 200 µm are highly contaminated especially with hydrocarbons and heavy metals. AKW Apparate + Verfahren GmbH has developed a special attrition process with extraordinary decontamination possibilities of this particle size range (63µm – 2 mm). Their high-performance attrititor is the main processing apparatus for the fines in a wet-mechanical soil and mineral waste washing plant measuring up to the high Swiss waste standards. The whole plant was designed and delivered within 12 months. The total capacity is approx. 30 t/h with a fines ratio of up to 40 %. The plant consists of a gravel and a sand purification unit, a process and a waste water treatment section.

The greatest part of the contaminants is in the organic part of the soil. In the gravel fraction a separation of the organic part removes the contaminants. In the fines and the sand fraction however the contaminants are due to the high specific surface area adsorptively bound to the particle surface. Here AKW Apparate + Verfahren GmbH developed a controlled high-performance attrition process. The sand fraction is fed to the high-performance attritor. There the surface of all sand particles has to be abraded by adhering to certain process parameters especially in regard to a high solids concentration (> 1300 g/l). The attritor is therefore equipped with a special sensor and a special control unit. After attrition the suspension consists of the abraded and now clean particles and the produced highly contaminated fine particles. Particles < 63 µm are separated by a hydrocyclone and fed to the waste water treatment plant. The powerful effect of the aggregates for the cleaning of the sand fraction was proved by different heterogeneous materials. The cleaned sand fraction is suitable to be an admixture to concrete or other applications.

Firing Range Closure to Prepare for Military Modernization

Matthew M. Smith, P.E., GZA GeoEnvironmental, One Edgewater Drive, Norwood, MA  02062, Tel:  781-278-5789, Email: msmith@gza.com
Kim M. Plunkett, Project Engineer, Commonwealth of Massachusetts Division of Capital Asset Management, One Ashburton Place, Boston, MA  02108, Tel: 617-727-4050 x225, Email: kim.plunkett@state.ma.us
Michael F. Conway, P.E., LSP, GZA GeoEnvironmental, Inc., One Edgewater Drive, Norwood, MA  02062, Tel: 781-278-3845, Email: mconway@gza.com

The Camp Curtis Guild Site Improvement Project included site work activities centered on the excavation, handling, stabilization, and replacement within a designated Activity and Use Limitation  (AUL) area of 7,800 tons of lead-contaminated granular and organic topsoil from two, currently inactive, firing ranges; Charlie Range and Delta Range.  Related site-work elements included installation and maintenance of sedimentation/erosion controls, clearing and grubbing, subsurface GPR survey for potential unexploded ordinance (UXO) anomalies, demolition of small onsite structures, removal/abandonment of utilities, offsite disposal of construction/demolition debris, and additional earthwork related to excavation, handling, and placement of approximately 23,000 cy of clean granular soil to achieve finish grades.  This work was performed in preparation for future construction of a new vehicle storage and maintenance facility.  Key elements of the project included:

Excavation work including removal of soils from steeply sloped berm areas to depths ranging from 12-inches to 7 feet below ground surface

Identification of potential UXO anomalies required special investigations using low-impact, non-sparking, non-metal equipment by a licensed UXO clearance company.  This work commenced in August and was completed in September, 2005.

With UXO support oversight by specialty contractor, contaminated soil excavation, handling, and stabilization commenced in late September, 2005-subsequent discovery of five UXO objects occurred during this work

As the work progressed, two additional issues came to light; 1. Substantial increase in the amount of soil requiring stabilization and 2. Accommodating the increased quantities required the AUL area be expanded.

By the end of the project, over 15,000 tons of soil from the two ranges had been stabilized.  This represented an increase of almost 100% over the original contract amount.  Intrusive earthwork activities and soil stabilization were completed on December 3, 2005.  Related final grading and other ancillary earthwork items were completed by December 19, 2005.

Enhanced Chlorinated Solvent Dechlorination Using Groundwater Re-circulation for Effective Substrate Delivery

Brian Timmins, Enzyme Technologies, 5228 NE 158th Ave., Portland, OR 97230, Tel: 503-546-3625, Fax: 503-254-1722, Email: brian@enzymetech.com
David Laughlin Enzyme Technologies, 5228 NE 158th Ave., Portland, OR 97230, Tel: 503-546-3621, Fax: 503-254-1722, Email: david@enzymetech.com

A pilot demonstration was conducted in 2005 to assess the potential of enhanced anaerobic dechlorination to remediate groundwater and soil impacted with PCE and its’ associated daughter products.   Pilot test dimensions were 50 feet by 50 feet, and the saturated thickness of 15 feet.  Groundwater was also impacted with diesel-range hydrocarbons (3-5 mg/L), which had already promoted the dechlorination of PCE to TCE, DCE, and VC in the saturated zone.  A low-cost, nutrient-amended substrate was used to enhance the dechlorination of the chlorinated solvents to ethene/ethane.

A re-circulation approach was used to distribute the amended groundwater throughout the pilot demonstration area.  The re-circulation approach utilized two extraction wells and three injection wells that were constructed at opposite ends of the test area.  Three performance monitoring wells were constructed at increasing distances (10, 20, and 30 feet) from the injection wells.  A trailer-mounted re-circulation system was used to re-circulate the amended groundwater.  Groundwater from the two extraction wells was pumped into a 350-gallon tank mounted on the trailer where the substrate was added at a specific rate.  Amended groundwater was then evenly injected into the three injection wells.  Approximately 44,000 gallons of groundwater was amended and injected into the saturated zone over a period of three weeks using this system.   

Groundwater performance monitoring data shows that within the first three weeks PCE and TCE were below detection limits, cis-DCE increased 3-8 fold, and VC increased from 0.1 to 2.5 fold in all monitoring wells.   Data from week four and five show cis-DCE concentrations decreasing by 23-76%, VC concentrations decreasing by 3-51%, and ethene/ethane concentrations increasing by 76-660% in all monitoring wells.  By week eight, three of the four monitoring wells had cis-DCE and VC concentrations below 5 ppb, and no rebound of PCE and TCE was observed.

Controlling Costs to Achieve Permanent Closure for a Quench Oil Site

Paul Uzgiris, P.E., Weston & Sampson Engineers, Inc, 5 Centennial Drive, Peabody, MA, 01960, Tel: 978-532-1900, Fax: 978-977-0100, email: uzgirisp@wseinc.com
Frank Ricciardi, P.E., Weston & Sampson Engineers, Inc, 5 Centennial Drive, Peabody, MA, 01960, Tel: 978-532-1900, Fax: 978-977-0100, email: ricciarf@wseinc.com
Kelley Race, P.G., LSP, Weston & Sampson Engineers, Inc, 5 Centennial Drive, Peabody, MA, 01960, Tel: 978-532-1900, Fax: 978-977-0100, email:racek@wseinc.com

In 1992, emergency response actions were conducted at a site following the discovery of quench oil flowing from a spring and discharging to lagoons. The quench oil release was attributed to former underground storage tanks located within a rail-right-of-way.  In 1994, an oil recovery interceptor trench was installed to capture migrating LNAPL. The site is classified under the Massachusetts cleanup regulations as having achieved a Temporary Solution.

This presentation will review cost-effective remedial measures evaluated and the success of the implemented measure to reach a Permanent Solution, cleanup of LNAPL. The existing remedial system consists of an impermeable barrier and product recovery trench with two product recovery systems installed in trench sumps. 

Cost, site, and technology constraints were considered as part of the permanent remedial evaluation and included:

• Location within an active rail-right of way

• Shallow groundwater table and nearby wetlands

• Soil excavation and off-Site recycling of contaminated soil

• Dewatering excavations and treatment of groundwater

• More productive and cost-effective LNAPL recovery

• Expense of remedial action relative to the risk

• Integration of the existing LNAPL recovery system with the permanent action

• Technically feasible remedial alternatives to achieve a Permanent Solution

In order to evaluate reaching a Permanent Solution, a high-vacuum extraction pilot study was initiated over a three-month period, consisting of six biweekly high-vacuum extraction events. This pilot study was evaluated to optimize the current remedial system and remove higher volumes of free-phase product from the subsurface of the site. The high vacuum events conducted during the three-month period removed over 700 gallons of LNAPL compared to less than 100 gallons in the past three years utilizing the existing systems. Based on the success of the vacuum extraction, a Permanent Solution without excessive soil excavation or permanent remediation systems is achievable.

Biosparging of a Smear-Zone Plume of Residual Diesel in the Sub-Arctic

David B. Ward, Ph.D.  Jacobs Engineering Group, 4300 B St Suite 600, Anchorage, AK 99503-5922, Tel: 907-751-3389, Fax: 907-563-3320, E-mail: david.ward@jacobs.com
Mollie L. TeVrucht, Ph.D.  US Army Engineer District, Alaska, PO Box 6898, Elmendorf AFB, AK 99506-0898, Tel: 907-753-2695, Fax: 907-753-5626, E-mail: Mollie.L.Tevrucht@poa02.usace.army.mil
Charley S. Peyton, B.A.  US Army Engineer District, Alaska, PO Box 6898, Elmendorf AFB, AK 99506-0898, Tel: 907-753-5718, Fax: 907-753-5626, E-mail: Charley.S.Peyton@poa02.usace.army.mil

Operations during the 1950s to early 1970s at the former fire-training pit at the Kodiak Airport (Kodiak, Alaska) contaminated a broad area adjacent to the Buskin River estuary with fuel (predominantly diesel).  Although excavation has removed the primary source, fuel is smeared at residual saturation through a three-foot interval at the water table by tidal and seasonal fluctuations.  Fluorescein dye moved rapidly through the underlying aquifer at up to 5 ft/day with high dispersion, but fuel-related textural changes in the smear zone appear to reduce permeability dramatically, inhibiting biodegradation by isolating the fuel from atmospheric or dissolved oxygen.

In a Fall 2005 pilot test, air sparging showed great promise as a means of aerating the smear zone.  One injection well and an array of twelve tri-level piezometer/soil-gas samplers arranged along the arms of a cross at distances of 7.5 to 60 ft served to evaluate air sparging.  The highly permeable aquifer matrix of sandy and silty gravels accommodated air injection at 102 scfm (the maximum that could be supplied) with a pressure of only 2 psig.  Soil-gas measurements of oxygen, carbon dioxide, and methane confirmed the initial anaerobic conditions within the smear zone and demonstrated that four hours of sparging achieved atmospheric gas concentrations in nearly all monitoring points.  The large radius of influence suggests that the low-permeability smear zone spread the injected air laterally.  Importantly, gas flushing in the smear zone was nearly uniform rather than focused on preferential pathways.

Soil-gas chemistry returned to near-baseline conditions after one to two days.  The rapid fall in oxygen probably reflected oxidation of abundant ferrous iron, but the rise in carbon dioxide may have been due to microbial respiration (along with unquantified desorption from mineral surfaces).  An estimated maximum degradation rate of 400 mg/kg/yr offers the possibility that average fuel concentrations could reach the cleanup level in two or three years of treatment.  The latest results from a multi-well test during the 2006 field season will be discussed.

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