Removal of PCBs from a Contaminated Soil Using CF-Systems® Solvent Extraction Process

ABSTRACT

The U.S. Environmental Protection Agency’s (EPA) Superfund Technical Assistance Response Team (START) in cooperation with EPA’s Superfund Innovative Technology Evaluation (SITE) program evaluated a pilot scale solvent extraction process developed by CF-Systems. This process uses liquefied propane to extract organic contaminants from soils, sludges, and sediments. A pilot-scale evaluation was conducted in Golden, CO at Hazen Research, Inc., using CF-Systems’ trailer-mounted organics extraction unit. Approximately 1,000 pounds of soil, with an average poly-chlorinated biphenyl (PCB) concentration of 260 mg/kg, was obtained from a remote Superfund site. Six 100-pound batches of the contaminated soil were extracted using multiple extraction sequences. Three of the six batch runs were subjected to three extraction sequences each, so that process variability could be evaluated. Results showed that PCB removal efficiencies varied between 91.4 and 99.4%, with the propane-extracted soils retaining low concentrations of PCBs (19.0–1.8 mg/kg). Removal efficiencies of oil and grease (O&G) were found to be 96.0 to 99.6% with propane-extracted soils retaining O&G concentrations from 279 to <20 mg/kg. Overall extraction efficiency was found to be dependant upon the numberof extraction cycles used.     

Thermal Encapsulation of Metals in Superfund Soils

Abstract

Superfund sites frequently contain both heavy metals and organic hazardous waste. If not properly controlled, the metals may be changed to a more leachable form and may also be emitted to the atmosphere via the exhaust stack. This paper documents a batch kiln R&D test program to solve these metal-related problems. It was performed under the U.S. EPA’s SITE (Superfund Innovative Technology Evaluation) Emerging Technology Program. Allis Mineral Systems has developed the Thermal Encapsulation Process. Metals with limits set by EPA’s TCLP (Toxicity Characteristic Leaching Procedure) test and BIF (boiler and industrial furnace) stack emission regulations, such as cadmium, chromium, and lead, are the initial target of this process. This process, while unproven in these areas, may also apply to mixed waste (EPA hazardous waste/low-level radioactive wastes) and may also benefit commercial hazardous waste or Superfund thermal treatment systems. The results of the SITE tests were positive: strong, durable nodules were produced with excellent crush strength and improved resistance to leaching. Feed preparation, particularly control of moisture content, was found to be a key element in initiation of agglomeration. A good correlation was found between decreasing TCLP metals leachate levels and increasing crush strength.     

EPA SITE Demonstration of the International Waste Technologies/Geo-Con In Situ Stabilization/Solidification Process

This paper presents an EPA evaluation of the first field demonstration of an in situ stabilization/solidification process for contaminated soil under the EPA Superfund Innovative Technology Evaluation (SITE) program. Demonstration of this process was a joint effort of two vendors: ? International Waste Technologies (IWT) of Wichita, Kansas, who provided the treatment process, specifically the proprietary additive called HWT-20, and

? Geo-Con, Inc., of Pittsburgh, Pennsylvania, who provided both engineering and hardware for the in situ soil treatment.

The field demonstration took place in April, 1988 at a site in Hialeah, Florida, contaminated mainly with polychlorinated biphenyls (PCBs). EPA tested the soil before and after treatment and the EPA evaluation of this process is based on results from this testing. A year later, in April 1989, EPA tested again the treated soil and results of that testing were compared to those of the demonstration. Results of the EPA evaluation of the IWT process, the Geo-Con performance, and treatment costs are discussed separately.     

Measurement of Ozone Levels by Ship Along the Eastern Shore of Lake Michigan

The U.S. Environmental Protection Agency (EPA), in cooperation with the Toronto Harbour Commissioners (THC), conducted a Superfund Innovative Technology Evaluation (SITE) demonstration of the THC Soil Recycle Treatment Train. The treatment train consists of three technologies operated in sequence: a soil wash process, a metals removal process, and a biological treatment process. The THC conducted an extensive demonstration of the treatment train at a 55 tons per day pilot plant in order to evaluate an approach for remediation of industrial/commercial sites that are situated in the Toronto Port Industrial District (PID). Three soils were processed during the THC demonstration. The EPA SITE demonstration project examined, in detail, soil processing from one of the sites being evaluated as part of the overall THC project. Contaminants included organic compounds and heavy metals. It has been estimated by THC that as much as 2,200,000 tons of soil from locations within the PID may require some form of treatment due to heavy metal and/or organic contamination that resulted from various industrial processing operations. The objective of the SITE demonstration was to evaluate the technical effectiveness of the process in relation to THC’s target criteria.

Gravel and sand that met the THC target criteria for medium to fine soil suitable for industrial/commercial sites was produced. The fine soil from the biological treatment process did not meet the target level of 2.4 ppm for benzo(a)pyrene. However, there was a significant reduction in polynuclear aromatic hydrocarbon (PAH) compounds. The metals removal process achieved reductions of greater than seventy percent for copper, lead, nickel, and zinc.     

1992 Update of U.S. EPA’s Superfund Innovative Technology Evaluation (SITE) Emerging Technology Program

The Superfund Innovative Technology Evaluation (SITE) Emerging Technology Program (ETP) has encouraged and financially supported further development of bench- and pilot-scale testing and evaluation of innovative technologies suitable for use at hazardous waste sites for five years. The ETP was established under the Superfund Amendments and Reauthorization Act (SARA) of 1986. The ETP complies with the goal of the SITE Program to promote, accelerate and make commercially available the development ofalternative /innovative treatment technologies for use at Superfund sites.

Technologies are submitted to the ETP through yearly solicitations for Preproposals. Following a technical review, chosen applicants are asked to submit a detailed project proposal and a cooperative agreement application that requires Developer I EPA cost sharing. EPA co-funds selected Developers for one to two years. Second-year funding requires documentation of significant progress during the first year. Facilities, equipment, data collection, performance and development are monitored throughout the project. The U. S. Department of Energy (DOE) and the U. S. Air Force (USAF) are participants in the ETP. DOE has co-funded ETP projects since 1990 and the USAF since 1991.

A primary goal of the ETP is to move developed technologies to the field-demonstration stage. Therefore, a developer may be considered for participation in the SITE Demonstration Program provided performance in the ETP indicates the technology is field-ready for demonstration and evaluation.

Six technology categories: biological, chemical, materials handling, physical, solidification/ stabilization and thermal, are presently in the ETP.

Technologies of primary interest to EPA are those that can treat complex mixtures of hazardous organic and inorganic contaminants and provide improved solids handling and/orpretreatment.

An account of the background and progress of the ETP’s first five years is presented in this paper. Technologies currently in the ETP, including those selected from the fifth (EOS) solicitation, are noted, and developers, along with EPA Project Managers, are listed.     

The Use of Electrokinetics for Hazardous Waste Site Remediation

The Superfund Innovative Technology Evaluation (SITE) program was authorized as part of the 1986 amendments to the Superfund legislation. It represents a joint effort between U.S. EPA’s Office of Research and Development and Office of Solid Waste and Emergency Response. The program is designed to assist and encourage the development of waste treatment technologies that would contribute to more solutions to our hazardous waste problems.

Recently, EPA, through the SITE program, issued a work assignment to assess the “stateof- the-art” of electroklnetically enhanced contaminant removal from soils. Prior research efforts, both laboratory and field, have demonstrated that electroosmosis has the potential to be effective In facilitating the removal of certain types of hazardous wastes from soils. Particularly encouraging results have been achieved with inorganics in fine-grained soils where more traditional removal alternatives are less effective.

Although the results of various studies suggest that electrokinetics is a promising technology, further testing Is needed at both the laboratory and field levels to fully develop this technology for site remediation. A conceptual test program Is presented based on best available data which incorporates system design and operating parameters used in previous applications of this technology In the use of electrokinetics treatment as a remediation technique at hazardous waste sites.     

1990 Update of the U.S. Environmental Protection Agency’s SITE Emerging Technology Program

The Superfund Amendments and Reauthorization Act of 1986 (SARA) directed the U.S. Environmental Protection Agency (EPA) to establish an Alternative/Innovative Treatment Technology Research and Demonstration Program. The EPA’s Office of Solid Waste and Emergency Response and the Office of Research and Development established a program called the Superfund Innovative Technology Evaluation (SITE) Program to accelerate the development and use of innovative cleanup technologies at hazardous waste sites. The SITE Program comprises of five areas: the Demonstration Program, the Emerging Technology Program, the Measurement and Monitoring Technologies Development Program, the Innovative Technologies Program, and the Technology Transfer Program.

This paper discusses the Emerging Technology Program (ETP) that supports the development of technologies that have been successfully tested at bench-scale level. Before a technology can be accepted into the Emerging Technology Program, sufficient data must be available to validate its basic concepts. The ETP enters into a co-funding effort with developers for a one- or two-year effort. Developers are responsible for contributing financial support and conducting the developmental research. After development and data collection, the technology’s performance is documented and a report is prepared, which may include recommendations for further developing the technology. If test results are encouraging, a technology may proceed with approval to a field demonstration.

The purpose of this article is to provide the reader with (1) an introduction to the Emerging Technology Program (2) an understanding of how the program operates (3) a summary of those technologies currently being tested and evaluated under the program and (4) information on how to apply to the program.     

Solvent Extraction Processes: A Survey of Systems in the SITE Program

Solvent extraction of contaminated soils, sludges and sediments has been successfully completed at a number of Superfund sites. Each commercialized process uses a unique operating system to extract organic contaminants from solids. These operating systems may be classified by the properties of the solvents each utilizes: (1) standard solvents, (2) near-critical fluids/liquified gases, and (3) critical solution temperature solvents. Pretreatment and post-treatment requirements vary depending upon the operating systems of the solvent extraction system. Future demonstrations of these technologies by the U.S. EPA’s Superfund Innovative Technology Evaluation Program will provide additional information regarding the efficacy of these processes.     

1990 Thermal Remediation Industry Contractor Survey

The treatment of soil contaminated with organics and inorganics is becoming a major industry in the United States and Europe. The soil cleanup bill for the United States could run as high as $200 to $300 billion over the next 30 to 40 years. European soil cleanup costs could run as high as $130 billion.¹

The types of sites in the United States that will require soil treatment can be broken down into the following categories: ? CERCLA (Superfund) Actions

? RCRA Corrective Actions

? RCRA Closures

? Underground Storage Tanks

? Real Estate Transfers

? Spill Clean-ups.

The cleanup of sites in each of these categories, with the exception of the Real Estate Transfer category, is being driven by different sets of Federal regulations. Real Estate Transfer type regulations were first instituted in New Jersey and have now been promulgated in a number of other states.

The eventual cleanup cost for the Superfund sites will be close to $200 billion. Estimated costs for the industrial sector Superfund are $25 to $50 billion and the estimated cost for the Department of Energy sites is over $150 billion.2 An early RCRA Corrective Action cleanup estimate is $25 billion.3 This estimate may well be low, however, since the permitting, cleanup and delisting criteria are still not clearly defined. The EPA’s RCRA Corrective Action cost estimate is $7.4 billion. However, the Office of Management and Budget feels that this estimate is low.⁴

The potential magnitude of the cleanup costs has resulted in the development and implementation of many technologies for the decontamination of soils. Of the available remedial technologies, thermal treatment has perhaps had the most field testing. The purpose of this paper is to focus on the full scale site remediations which have been or are being conducted using thermal processing equipment. Projects which have been completed, are on-going, or have been contracted for, through January of 1990 are described.     

U.S. EPA SITE Demonstration of AWD Technologies’ AquaDetox/SVE System

Under the Superfund Innovative Technology Evaluation (SITE) Program, a technology developed by AWD Technologies, Inc. was demonstrated in September 1990. This paper presents the major results of the SITE demonstration of AWD Technologies’ AquaDetox®ISVE treatment system designed for simultaneous on-site treatment of contaminated groundwater and soil-gas. The groundwater and soil at the demonstration site were contaminated with trichloroethylene (TCE) and tetrachloroethylene (PCE). The AWD technology was evaluated on the basis of the removal efficiencies of TCE and PCE from the contaminated groundwater and soil-gas. The conclusions drawn from these evaluations are: (1) the system achieved removal efficiencies as high as 99.99percent for groundwater and 99.9 percent for soil-gas; (2) the effluent groundwater was in compliance with the regulatory discharge requirements of 5 fig/L each for TCE and PCE for all test runs; (3) the demonstrated 1,000 gpm system has an estimated capital cost of $4.3 million and annual operating and maintenance cost of approximately $820,000.     

Alternating Current Electrocoagulation for Superfund Site Remediation

Abstract

The Superfund Innovative Technology Evaluation (SITE) Emerging Technology (ET) Program, authorized under the Superfund Amendments and Reauthorization Act (SARA) of 1986, implements the goal of the SITE Program to promote, accelerate the development of, and make commercially available alternative innovative treatment technologies for use at Superfund sites.

Under this program, the technical and economical feasibility of alternating current electrocoagulation (ACE) developed by Electro-Pure Systems, Inc., was evaluated for a two-year period. ACE is an electrochemical technology where highly-charged aluminum polyhydroxide species are introduced into aqueous media for the removal of suspended solids, oil droplets and soluble ionic pollutants. ACE can break stable aqueous colloidal suspensions of up to 10 percent total solids and stable emulsions containing up to 5 percent oil.

Major operating parameters have been defined for different classes of effluents based on experimental results using complex synthetic soil slurries and metals. Test results indicate that ACE produces aqueous and solid separations comparable to those produced by chemical flocculent additions, but with reduced filtration times and sludge volumes. The technology has application where removal of soluble and suspended pollutants from effluents is required, and in the recovery of fine-grained products from process streams. The technology, however, has not yet been demonstrated at full-scale for Superfund site remediation. The principal results of the SITE research program, and results of ACE treatment on some different classes of industrial effluents not part of the SITE Program, are summarized.     

Treatment of polychlorinated biphenyls in two surface soils using catalyzed H₂O₂ propagations

Two surface soils contaminated with polychlorinated biphenyls (PCBs) collected from Superfund sites in the New England region of the United States, Fletcher Paints and Merrimack Industrial Metals, were evaluated for field treatment at the bench level using catalyzed H₂O₂ propagations (CHP—modified Fenton’s reagent). The two soils were first evaluated for the potential for in situ treatment based on two criteria: (1) temperature (<40 °C after CHP reagent addition), and (2) hydrogen peroxide longevity (>24 h). In situ CHP remediation was more applicable to the Fletcher soil, while the Merrimack soil was better suited to ex situ treatment based on temperature increases and hydrogen peroxide lifetimes. Using the highest hydrogen peroxide concentrations appropriate for in situ treatment in each soil, PCB destruction was 94% in the Fletcher soil but only 48% in the Merrimack soil. However, 98% PCB destruction was achieved in the Merrimack soil using conditions more applicable to ex situ treatment (higher hydrogen peroxide concentrations with temperatures >40 °C). Analysis of degradation products by gas chromatography/mass spectroscopy showed no detectable chlorinated degradation products, suggesting that the products of PCB oxidation were rapidly dechlorinated and degraded. The results of this research document that the two PCB-contaminated soils studied can be effectively treated using aggressive CHP conditions, and that such a detailed bench study provides important information before implementing field treatment.     

A Comparison of Two Techniques for the Collection and Analysis of Polynuclear Aromatic Compounds in Ambient Air

A demonstration of the GHEMFIX solidification/stabilization process was conducted under the United States Environmental Protection Agency’s (EPA) Superfund Innovative Technology Evaluation (SITE) program. The demonstration was conducted in March 1989, at the Portable Equipment Salvage Company (PESC) uncontrolled hazardous waste site in Clackamas, Oregon. Waste containing lead, copper, and polychlorinated biphenyls (PCBs) from four different areas of the site were treated. Results showed substantial reduction of leachable lead and copper between the untreated waste and treated waste utilizing the EPA Toxicity Characteristics Leaching Procedure (TCLP) test. The effectiveness of this process for immobilizing PCBs could not be determined since the raw waste did not leach PCBs at high concentrations, utilizing the TCLP test. Data from other leaching tests for lead and copper would need to be utilized as input into a site specific groundwater model to determine whether solidification/stabilization would be an acceptable remedy for the site. Physical testing results indicated durability in exposed conditions.     

SITE Demonstration of the CF Systems Organic Extraction Process

The CF Systems Organic Extraction Process was used to remove PCBs from contaminated sediment dredged from the New Bedford Harbor. This work was done as part of a field demonstration under EPA’s Superfund Innovative Technology Evaluation (SITE) program. The purpose of the SITE program is to provide an independent and objective evaluation of innovative waste remediation processes. The purpose of this paper is to present the results of the SITE demonstration of this technology. Results of the demonstration tests show that the system, which uses liquefied propane, successfully removed PCBs from contaminated sediments in New Bedford Harbor. Removal efficiencies for all test runs exceeded 70 percent. Some operational problems occurred during the demonstration which may have affected the efficiency with which PCBs were removed from the dredged sediment. Large amounts of residues were generated from this demonstration project. Costs for using this process are estimated to be between $150/ton and $450/ton.     

U.S. EPA SITE demonstration of AWD Technologies' AquaDetox/SVE system.

Under the Superfund Innovative Technology Evaluation (SITE) Program, a technology developed by AWD Technologies, Inc. was demonstrated in September 1990. This paper presents the major results of the SITE demonstration of AWD Technologies' AquaDetox/SVE treatment system designed for simultaneous on-site treatment of contaminated groundwater and soil-gas. The groundwater and soil at the demonstration site were contaminated with trichloroethylene (TCE) and tetrachloroethylene (PCE). The AWD technology was evaluated on the basis of the removal efficiencies of TCE and PCE from the contaminated groundwater and soil-gas. The conclusions drawn from these evaluations are: (1) the system achieved removal efficiencies as high as 99.99 percent for groundwater and 99.9 percent for soil-gas; (2) the effluent groundwater was in compliance with the regulatory discharge requirements of 5 micrograms/L each for TCE and PCE for all test runs; (3) the demonstrated 1,000 gpm system has an estimated capital cost of $4.3 million and annual operating and maintenance cost of approximately $820,000.     

Distribution of Pb, Cd and Ba in soils and plants of two contaminated sites

Evaluation of metal accumulation in soils and plants is of environmental importance due to their health effects on humans and other biota. Soil material and plant tissue were collected along transects in two heavily contaminated facilities, a Superfund site and a lead-acid battery dump, and analyzed for metal content. Soil lead (Pb), cadmium (Cd) and barium (Ba) concentrations for the Superfund site averaged 55,480, 8.5 and 132.3 mg/kg, respectively. Soil Pb occurred primarily in the carbonate, sulfide/residual and organic chemical fractions (41.6, 28.6 and 16.7%, respectively). Soil Pb, Cd and Ba concentrations for the dump site averaged 29,400, 3.9 and 1130 mg/kg, respectively. Soil Pb occurred mostly in the organic and carbonate fractions as 48.5 and 42.5%, respectively. Pb uptake in the two sites ranged from non-detectable (Agrostemma githago, Plantago rugelii, Alliaria officinalis shoots), to 1800 mg/kg (Agrostemma githago root). Cd uptake was maximal in Taraxacum officinale at 15.4 mg/kg (Superfund site). In the majority > or =65%) of the plants studied, root Pb and Cd content was higher than that for the shoots. Tissue Pb correlated slightly with exchangeable and soluble soil Pb; however, tissue Cd was poorly correlated with soil Cd species. None of the sampled plants accumulated measurable amounts of Ba. Those plants that removed most Pb and Cd were predominantly herbaceous species, some of which produce sufficient biomass to be practical for phytoremediation technologies. Growth chamber studies demonstrated the ability of T. officinale and Ambrosia artemisiifolia to successfully remove soil Pb and Cd during repeated croppings. Tissue Pb was correlated with exchangeable soil Pb at r(2)=0.68 in Ambrosia artemisiifolia.     

Assessment of Needs for Technical Information in EPA’s Hazardous and Solid Waste Programs

Headquarters managers and Regional staff in the U.S. Environmental Protection Agency’s hazardous and solid waste programs were surveyed to determine priorities for technical information and guidance among EPA Regional staff, state hazardous waste management staff, EPA contractors, and the regulated community. The survey also examined delivery systems effective for EPA Regional staff. The fifteen highest ranked technical needs for RCRA, Superfund, and UST reflect a pervasive interest in hazardous waste remediation. Top priority technical needs focus on establishing cleanup levels, subsurface fate and transport, field monitoring and quality assurance, remedy selection, and most importantly, which remedies work and which do not in specific situations. Technical needs of non- EPA audiences are quite similar to those for EPA field staff. Preferences for technology transfer delivery systems are generally for conventional distribution methods (such as print materials and workshops) rather than electronic or video media. Regional staff report serious problems in utilizing technology transfer because of time constraints, insufficient knowledge of available products, insufficient travel funds, and limited access to and training on computers.     

Canister-Based Method for Monitoring Toxic VOCs in Ambient Air

The availability of reliable, accurate and precise monitoring methods for toxic volatile organic compounds (VOCs) is a primary need for state and local agencies addressing daily monitoring requirements related to odor complaints, fugitive emissions, and trend monitoring. The canister-based monitoring method for VOCs is a viable and widely used approach that is based on research and evaluation performed over the past several years. This activity has involved the testing of sample stability of VOCs in canisters and the design of time-integrative samplers. The development of procedures for analysis of samples in canisters, including the procedure for VOC preconcentration from whole air, the treatment of water vapor in the sample, and the selection of an appropriate analytical finish has been accomplished. The canister-based method was initially summarized in the EPA Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air as Method TO-14. Modifications and refinements are being added to Method TO-14 in order to obtain a Statement of Work for the Superfund Contract Laboratory Program for Air. This paper discusses the developments leading to the current status of the canisterbased method and provides a critique of the method using results obtained in EPA monitoring networks.     

Demonstration of In Situ Steam and Hot-Air Stripping Technology

Between September 5 and October 5,1989 a field demonstration of the NovaTerra, Inc. Detoxifier [formerly called Toxic Treatment (USA)] was performed by the U.S. EPA under the Superfund Innovative Technology Evaluation (SITE) program. The NovaTerra Detoxifier process injects steam and hot air directly into the ground to vaporize and strip volatile and semivolatile organics. Two augers loosen and homogenize the soil during the stripping process. The steam, hot air and organics are carried to the soil surface and collected for treatment.

The field demonstration was performed at the GATX Annex Terminal located at the Port of Los Angeles, San Pedro, California. Approximately 17 percent of the 5.2 acre site is contaminated with chlorinated solvents, plasticizers, coatings, adhesives and paint additives, and other miscellaneous chemicals from aboveground storage tanks and transfer operations to railroad cars.

The objectives of this SITE Demonstration were to determine the in situ soil concentrations before and after treatment, quantify process stream emissions (fugitive and sidestreams), determine process operating conditions, and determine if vertical migration of contaminants is occurring. Results from the SITE demonstration showed that a substantial amount of the VOCs were removed, about half the SVOCs were removed, there was very little fugitive air emissions from the operation, and what little downward migration occured (if any) was inconsequential.