»' Office of gtnargarjGy and - Office of Retrial Response « ' Re$e§ir«Qh (^ 00 20460 , May 1QS7 v>EPA ngimgnng Teah nplpgy for th0 lm&diatlon of Soil Purpose Section 121(b) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), man- dates the U.S. Environmental Protection Agency (EPA) to select remedies that "utilize permanent solutions and alter- native treatment technologies or resource recovery tech- nologies to the maximum extent practical" and to prefer remedial actions in which treatment "permanently and sig- nificantly reduces the volume, toxicity, or mobility of hazard- ous substances, pollutants, and contaminants as a principal element." The Engineering Bulletins are a series of docu- ments that summarize the latest information available on selected treatment and site remediation technologies and related issues. They provide summaries of and references for the latest information to help remedial project managers, on-scene coordinators, contractors, and other site cleanup managers understand the type of data and site characteris- tics needed to evaluate a technology or technologies for potential applicability to their Superfund or other hazardous waste site. Those documents that describe individual treat- ment technologies focus on remedial investigation scoping needs. Addenda will be issued periodically to update the original bulletins. Abstract Pesticide contamination includes a wide variety of com- pounds and may result from manufacturing improper stor- age, handling, disposal; or agricultural processes. It can occur in soil and can lead to secondary contamination of groundwater. Remediation of pesticide-contaminated soils can be a complicated process, as most pesticides are mixtures of different compounds rather than pure pesticide. The remedial manager is faced with the task of selecting remedial options that will meet established cleanup levels. There are three principal options for dealing with pesticide contamination: containment/immobilization, destruction, and separation/concentration. This bulletin focuses on soils and current or soon-to-be available separation/concentra- tion pesticide remediation technologies. The information presented is condensed from the technical resource docu- ment "Contaminants and Remedial Options at Pesticide Sites" [1] and other available literature. Technologies that have not produced performance data are not included nor are water, sludge, or sediment treatment technologies. The resource document contains site-specific information on pesticide contamination and the remediation techniques used. Background Pesticides, as defined by the U.S. Federal Environmen- tal Pesticide Control Act, are "...any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any insect, rodent, nematode, fungus, weed or any other form of terrestrial or aquatic plant, animal life, or virus, bacteria or other microorganism which the Adminis- trator declares a pest" [2]. Pesticides include insecticides, fungicides, herbicides, acaricides, nematocides and roden- ticides as well as any substance or mixture of substances intended for use as a plant regulator, defoliant or desiccant. Pesticides do not include such substances as fertilizers or veterinary medicines [1]. The EPA has developed extensive data on specific pesticide products and wastes through the pesticide registration program and site investigation [3,4,5]. Pesticide wastes are generally complex chemical mix- tures and not pure pesticides. These mixtures can include solvents, carriers and other components that will have a direct effect on toxicity, mobility, transport and treatment. The resource document categorizes pesticides into four waste groups based on available treatment technolo- gies [1]. The four waste group categories are: WG01 - Inorganic pesticides WG02 - Halogenated water insoluble organics WG03 - Halogenated sparingly water soluble organics and organo-linked compounds WG04 - Nonhalogenated organics and organo-linked compounds. Table 1 details the four pesticide waste groups and gives examples of commonly found pesticides. These groups are subdivided further to show the chemical class or indicate references Printed on Recycled Paper ------- Tablo 1. Pesticide Chemical Waste Groups." [1,6] Postlckle Chemical Waste Group WQ01 - Inorganics WG02 - Halogenated water insoluble organics WG03- Halogenated sparingly water soluble organics and organo- linkod compounds WG04 - Nonhalogenated organics and organo-linked compounds Family Organochlorine/ DDT analog DDT analog uyciodiene Hexachlorocyclohexane Toxaphene Nitrated aromatics Nitrated aliphatics Alkylmercaptan Carboxamide Triazine Halogenated phenol Halogenated volatile aliphatics Aryloxyalkanoic acid Phosphorothioate Dinitroaniline Unsaturated aliphatics Thiourea Alkaloids Carbamates Phosphonates Phosphorothioates •The Bulletin covers only the technologies in bold. Discussions Example Lead arsenate Sodium fluoride Zinc phosphide ODD DDE DDT Methoxychlor Alarm Chlordane Dieldrin Endosulfan Endrine Heptachlor a-BHC /3-BHC 7- BHC (lindane) Toxaphene Pentachloro- nitrobenzene Chloropicrin Captan Alachlor Pronamide Cyanazine Pentachlorophenol (PGP) Dibromochloropropane (DBCP) Ethylene dibromide (EDB) Methyl bromide 2,4-D 2,4,5-TP (silvex) Methyl parathion Trifluralin Acrolein Ethylene oxide Ethylene thiourea (ETU) Allethrin Rotenone Aldicarb Benomyl Carbaryl Diazinon Glyphosate Dimethoate Marathion Parathion Phorate on the other technologies can Applicable Soil Treatment Technologies Chemical oxidation Soil flushing Stabilization/Solidification Soil washing Incineration Bioremediation Dehalogenation/Hydrodehalo- genation Hydrolysis/Neutralization Ultra high temperature processes Soil flushing Soil washing Thermal desorption Steam extraction Solvent extraction Supercritical CO2 extraction Adsorption Filtration Chemical reduction Chemical oxidation Radio frequency heating Incineration Bioremediation Dehalogenation/Hydrodehalo- genation Hydrolysis/Neutralization Ultra high temperature processes Soil flushing Soil washing Soil vapor extraction Thermal desorption Steam extraction Solvent extraction Supercritical CO2 extraction Chemical oxidation Adsorption Filtration Chemical reduction Radio frequency heating Incineration Bioremediation Hydrolysis/Neutralization Ultra high temperature processes Soil flushing Soil washing Thermal desorption Steam extraction Solvent extraction Supercritical CO2 extraction Chemical oxidation Adsorption Filtration Chemical reduction be found in the resource document. Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- family each pesticide belongs to according to their molecu- lar structure or key functional group. Applicable treatment technologies for each waste group are also provided. Ref- erences to pesticides and pesticide wastes in this document use the above waste group categories. Most pesticides readily adsorb on soils because of their high adsorption capacity. In fact, adsorption of pesticides on the soil surface is a dominant factorthat affects the extent of the site contamination. As a rule, when applied properly, pesticides migrate slowly. Concentrated pesticide from a spill or leak, however, can move more quickly into the subsurface, especially if the pesticide is in aqueous phase or under the influence of percolating water [1 ]. Mechanisms of pesticide fate and transport that affect the extent of site contamination include: Adsorption on soils Biodegradation Volatilization Downward migration Lateral migration Photolysis. Selecting a remedial strategy includes considering the individual contaminant's toxicity, persistence, migration pathways and rate of transport from a site. The wide range of physical and chemical properties of pesticides also influ- ence the selection of an appropriate remedial technology or combination of technologies (known as a treatment train). It is important to gain information specific to the pesticide(s) present in order to effectively identify the treatment technology(ies) that is most applicable and cost effective. Separation/Concentration Options Treatment technologies or control options for pesti- cides fall into three categories: containment/immobilization, destruction and separation/concentration. This document addresses the separation/concentration options. Separation/concentration technologies primarily serve to separate contaminants from soils, thereby concentrating the waste stream and reducing the amount of material that must be treated. These technologies are mainly used as a pretreatment step, since no destruction or reduction of toxicity is attained. Separation/concentration technologies can be classi- fied as follows: • In situ technologies - Soil flushing - Soil vapor extraction (SVE) - Steam extraction - Radio frequency (RF) heating • Ex situ technologies (excavated soils) - Thermal desorption - Soil washing - Solvent extraction - Supercritical CO2 extraction. The decision to select and implement these techniques rests primarily on the action levels established for the site. Key issues for these technologies are the management, treatment and disposal options for the process extract phase. While not discussed in this bulletin, regulatory compliance and disposal criteria for extract-phase materials must be addressed. Separation/concentration technologies can potentially be applied to pesticide wastes in all four waste groups. Soil flushing, SVE and steam extraction technologies have lim- ited applicability to pesticide-contaminated soils, thus these separation/concentration technologies are not discussed in this document. In this bulletin, the following separation/ concentration technologies most applicable to pesticide- contaminated soils are discussed: - Radio frequency heating - Thermal desorption - Soil washing - Solvent extraction - Supercritical carbon dioxide (CO2) extraction. For each separation/concentration option presented, the following items are discussed: Process description Data needs for technology implementation Technology performance in treating pesticides in soils Process residuals (if available) Site-specific regulatory requirements or goals (if avail- able). Radio Frequency Heating Radio frequency (RF) heating is an in situsofi treatment process that uses electromagnetic energy in the radio fre- quency band to heat soil rapidly. During this process, the contaminants are vaporized and/or boiled out along with water vapor formed by the boiling action of native soil moisture. The gases and vapors formed upon heating the soil are recovered and treated on site. This combination of vaporization, boiling, and steam stripping has been used effectively in removing aldrin, dieldrin, endrin, isodrin (WG02) and other pesticides that typically volatilize in the tempera- ture range of 80°C to 300°C, such as volatile aliphatics (WG03). This technology offers three distinct advantages: • the contaminated materials do not need to be exca- vated; • the contaminants are removed from the soil as vapors and can be subsequently trapped and treated in a vapor treatment system (process equipment may be trailer mounted and mobile); • the presence of other contaminants such as jet fuel, polychlorinated biphenyls (PCBs), creosote, petroleum hydrocarbons, does not limit the treatment effective- ness of the process [7,8,9]. Process Description The RF soil decontamination process heats a defined volume of soil in situ to temperatures of 80°C to 300°C by Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- means of an electrode array inserted in bore holes drilled Into the soil. The process uses electromagnetic energy in the frequency range of 2 to 13 megahertz to achieve high soil temperatures. The actual frequency depends upon the volume and depth of the treated soil and the dielectric properties of the soil. The electrodes, spaced evenly apart in the soil, are 2 to 15 ft long. The soil between the electrodes is heated by the RF energy during treatment. Some of the electrodes are perforated to serve as vapor collection lines which are manifolded to a vapor treatment system [7,8,9]. Data Needs for Technology Implementation The data needs for RF heating are presented in Table 2. Performance A field pilot demonstration of this technology was con- ducted at the Rocky Mountain Arsenal. The pesticide- contaminated soil was a mixture of clay and sand to a depth of 12 feet and gravely sand to a 17-ft depth. The results are summarized in Table 3. The initial concentrations shown are the average of 36 samples at depths of 7 to 17 ft. The final contaminant concentrations shown are averages in the 200-250°C, 250-300°C, and >300°C temperature ranges. The contaminant removal percentage was greater than 98 percent. The preliminary cleanup goals, set by EPA and state agencies, were developed on a risk-based assessment of 10-6 biological worker exposure. Table 4 shows the final pesticide concentrations in treated soil for each of the three treatment temperature ranges, with the associated cleanup goal for each pesticide. The data indicate that the best Table 2. Data Needs for Radio Frequency Heating. [7,8] Data Needs Possible Effects Type of soil Presence of metal drums or metallic debris Type of contaminants(s) Soil moisture content Row rate and depth of groundwater table Low permeability soils increase costs and decrease contaminant recovery; dielectric properties of soil determine RF power requirement Disrupts current flow; may interfere with electode placement Requires supplementation with other treatment methods if nonvolatile contaminants (boiling points >300°C), heavy metals, or inorganic salts are present High moisture content increases energy requirements and impacts removal efficiency of organic contaminants Presence of fast moving groundwater in heated zone acts as an energy sink and negatively impacts process cost; may require diversion of water from heated zone by slurry walls, etc. Table 3. Results of Radio Frequency Heating Pilot Test Program at Rocky Mountain Arsenal Over All Temperature Ranges Tested". [7] Pesticide Initial Concentration (ppm) Final Concentration (ppm/ Percent Removal Aldrin DIeldrin Endrin Isodrin 1100 490 630 2000 11.3 3.2 2.8 33 99.0 99.3 99.6 98.4 a200-250°C, 250-300°C, and >300°C Table 4. Rnal Concentrations of Compounds versus Soil Temperature in Radio Frequency Test at Rocky Mountain Arsenal [9]. Pesticide Aldrin DIeldrin Endrin Isodrin 200-250°C Concentration (mg/kg) 0.97(±1.0)a 0.59 (±0.35) 1.7 (±2.0) 1.3 (NA)b 250-300°C Concentration (mg/kg) 31 (±40) 8.0 (±8.0) 5.6 (±5.3) 48 (±62) >300°C Concentration (mg/kg) 1.8 (±3.1) 1.0 (±1.5) 1.1 (±1.5) 49 (±90) Preliminary Remediation Goal (mg/kg) 0.56 0.40 17 3.6 "Values in parentheses represent the standard deviation of the concentration given bNA s Not available Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- overall treatment was achieved in soils heated to between 200 and 250°C. In this temperature range removal of both endrin and isodrin met the cleanup criteria [9]. Process Residuals The vapors and gases collected by the second step of the process require treatment, combustion and/or scrubbing to remove acid gases. The condensed liquids from the collection phase are separated into aqueous and organic fractions. The aqueous phase is treated using activated carbon and filtration. The organic phase is collected for destruction at an approved facility [7,8,9]. Thermal Desorption Thermal desorption is an innovative ex situ technology which includes a broad range of processes using thermal energy (e.g., heated air, infrared volatilization, laser-in- duced desorption, etc.) to remove volatile and semivolatile organic and inorganic compounds from contaminated soil. Thermal desorption is applicable to pesticide waste from waste groups WG02, WG03, and WG04. Toxicity is not affected by thermal desorption; the toxic compounds are removed from the soil for further treatment or disposal [1]. Process Description Thermal desorption is used to desorb low, medium and high boiling-point organic pesticides. Front-end material handling steps such as excavation, dewatering and/or dredg- ing are performed. High soil moisture content may require greater energy usage, but it may also enhance volatilization by producing steam within the media. The desorption units typically require at least 20 to 30 percent solids by weight. Some units can accept only 10 percent total organic carbon loading by weight. The media enters the desorber unit and is heated to temperatures between 95 and 540°C. A temperature above 150°C may be required to effectively desorb medium-to- high boiling point organic pesticides. The vapors generated from the process can be destroyed/oxidized in an after- burner. The afterburners operate in excess of 870°C and have a fluid residence time sufficient to achieve a destruc- tion efficiency greater than 99.99 percent. The efficiency of thermal desorption is primarily depen- dent on the bed temperature and residence time in the unit. Residence time determines the soil treatment temperature for a given airflow rate. The resulting air and soil tempera- tures affect the rate and degree of contaminant desorption. A temperature differential of approximately 95°C higher than the boiling point of a pesticide is required to achieve complete desorption and to overcome the intrinsic heat transfer resistances present in the medium [1,11]. Data Needs for Technology Implementation The data needs are presented in Table 5. Performance Thermal desorption technology has been used in sev- eral remedial actions including three Superfund sites. The Low Temperature Thermal Aeration (LTTA) System is a Table 5. Data Needs for Thermal Desorption. [12,13,14] Data Needs Possible Effects Moisture content Particle size distribution Total solids content PH Contaminant concentrations Presence of metals or inorganics Volatile metals Total chlorine Total petroleum hydrocarbons Vapor pressure Boiling point Adsorptive properties of contaminant High moisture content (>20%) increases energy requirement; dewatering or pretreatment may be required Oversize (>1-1.5 in.) particles may require size reduction or screening; presence of fine silt or clay may generate fugitive dust loading for air pollution control equipment Usually a minimum of 20-30% solids is required Very high (>11) or low (<5) soil pH may result in corrosion of system components Total organic bonding is limited to approximately 10%; higher organic bonding may result in incomplete processing Are not likely to be treated effectively May concentrate in off-gas and require additional treatment May affect volatilization of some metals High concentrations may require a thermal oxidizer or afterburner and a quench tower for cooling Affects removal effectiveness; high contaminant vapor pressure increases removal efficiency and requires less energy for contaminant removal Affects process temperature and removal effectiveness; low boiling point reduces energy requirements for contaminant removal Affects amount of energy required to desorb contaminant from soil particles Engineering Bulletin: Separation/Concentration Technology Alternatives lor the Remediation of Pesticide-Contaminated Soil ------- remedial system developed by Canonie Environmental Ser- vices Corporation. The LTTA System thermally desorbs organic compounds from contaminated soil without heating the soil to combustion temperatures. The system performs three main operations: soil treatment, emissions control and process water treatment. LTTA systems can treat a wide variety of soils having different moisture and contami- nant concentrations, and can remove pesticides from soil to below br near analytical detection limits [11]. The LTTA System was used in a full-scale Superfund Innovative Technology Evaluation (SITE) demonstration conducted at an abandoned pesticide mixing facility in western Arizona. The facility stored and mixed several pesticides including toxaphene, DDT, ODD, and DDE. The Arizona pesticide site was remediated under supervision of the slate by voluntary action of the potentially responsible party. All treated soils at the site were required to contain less than 5 mg/kg total pesticide after one pass through the LTTA system, as stated in the remedial action plan. An estimated 51,000 tons of contaminated soil required treat- ment. Sliding scale cleanup criteria were established, shown in Table 6, with a maximum allowable concentration of 1.09 mg/kg of toxaphene with no DDT/DDD/DDE (com- bined) at one end, and a maximum allowable concentration of 3.53 mg/kg DDT/DDD/DDE with no toxaphene at the other end. Treated soils met the specific cleanup criteria if 90 percent of the treated soil fell within the cleanup criteria on a daily basis. The LTTA SITE demonstration consisted of three sepa- rate runs, each requiring about 8 hr to complete. Based on site characterization data of the contaminant distribution, the soil was treated to a depth of 2 ft. This soil was primarily clay-like in nature (40 percent fines). Table 6. Sliding Scale Cleanup Criteria Concentrations for Pesticides During the LTTA™ SITE Demonstration of Thermal Desorption [14]. DDT/DDD/DDE (mq/kg) 0.00 0.01 0.83 1.00 2.00 3.00 3.36 3.52 Toxaphene (mg/kg) 1.09 1.087 0.83 0.78 0.47 0.16 0.05 0.00 Table 7. Pesticide Concentrations and Removal Efficiencies in LTTA™ SITE Demonstration of Thermal Desorption Technology. [14] Pesticide Toxaphene DDT ODD DDE Cone. Range in Feed Soil, mg/kg 4.5 to 47 1.2 to 54 0.027 to 0.86 3.7 to 15 Average3 Concentration. Run 1 Feed Soil 27.5 24.1 0.34 7.1 Treated Soil <0.017 <0.001 <0.0003 1.1 Run 2 Feed Soil 16.5 22.8 0.12 8.3 Treated Soil 0.017 0.001 <0.0003 0.97 , mg/kg Run 3 Feed Soil 10.8 9.3 0.2 5.1 Treated Soil <0.025 0.002 <0.001 0.28 Removal, % Run 1 >99.9 >99.9 >99.9 90.2 Run 2 >99.9 99.9 >99.7 88.4 Run 3 >99.8 99.9 >99.8 93.3 •"Average of four composite samples for each feed or treated soil value Demonstration results, shown in Table 7, indicate toxa- phene, DDT, ODD, and DDE removals in excess of 99 percent for each of the three runs. The remedial cleanup criteria were met during each of the runs [11,14]. Williams Environmental Services (WILLIAMS) com- pleted a treatability study using the WILLIAMS thermal dosorption system for a removal action at a former pesticide formulation site (T H Agriculture and Nutrition Company) in Albany, GA. The removal action, which included treatment of approximately 3,000 tons of soil contaminated with over 1,000 mg/kg total pesticides, was overseen by EPA and the Georgia Department of Natural Resources Environmental Protection Division. Treatability study results showed that at a soil treatment temperature of 500°F, total pesticide removal ranged from 86 to 93 percent; when operated at a treatment temperature of 700°F, pesticide removal was more than 99 percent. At 700°F, the total pesticide concen- tration was reduced from about 200 mg/kg to less than 0.003 mg/kg [15]. Process Residuals This innovative technology produces the following three residual streams: • Decontaminated soil, sludge or sediment • Scrubber water from the air pollution control system • Off-gas emissions from the air pollution control system [1]- Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- The decontaminated media may be reclaimed after analysis. The scrubber water can be treated onsite or discharged to a publicly-owned treatment works (POTW). Off-gas emissions may require additional air pollution con- trol before being released through a stack [1]. Soil Washing Soil washing is an innovative ex situ technology which uses an aqueous solution to decontaminate soils. Contami- nant removal or volume reduction is achieved by one or more of the following mechanisms: 1) the contaminants are suspended or dissolved in the wash solution, 2) the con- taminants are concentrated by segregating the most con- taminated fraction from the bulk of the soil using size- separation techniques or 3) the contaminants are concen- trated by segregating dense, paniculate contaminants through the use of density-separation techniques [16,17,18,19,20,21]. Each of the four pesticide chemical waste groups (Table 1) can potentially be treated using the soil washing technology [1]. Process Description Soil washing systems consist of specific unit operations (subsystems) that are tailored to accommodate the site conditions and soil characteristics. In general, soil washing systems consist of three types of subsystems: • feedstock preparation • soil washing • residuals treatment. Feedstock preparation includes excavation, transpor- tation of the soil to the soil-washing staging area, removal of debris and separation of the soil into different particle-size or density fractions. Typical post-excavation operations include screening, crushing and attrition scrubbing. The purpose of feedstock preparation is to segregate the soil components into fractions based on contamination levels. Minimally contaminated soils, requiring little or no treat- ment, can be returned to the site as backfill, but highly contaminated fractions require more aggressive treatment. Reducing the volume of soil passing through the remainder of the system increases the cost-effectiveness of the tech- nology [16,17,18,19,20,21]. Soil washing unit operations tend to fall into two catego- ries: physical separation of the soil matrix into different particle-size or density fractions, and chemical separation of the contaminants from the soil matrix. Organic contami- nants such as pesticides are often concentrated in the fines (e.g., clays and silt). Physical separation of this fraction using unit operations such as flotation, gravity settling, hydrocloning, washing and rinsing achieves further volume reduction [16,17,18,19,20,21]. Chemical separation trans- fers the contaminant from the soil matrix to the aqueous- phase wash solution. Chemical separation can be en- hanced by optimizing process conditions. Increased wash or rinse temperature, addition of surfactant and pH adjust- ment may enhance pesticide removal [16,17,18,19,20,21]. Residuals treatment subsystems include unit opera- tions that treat process water, air emissions and highly contaminated fractions of the soil, such as the fines. The unit operations typically include biological, chemical or ther- mal oxidation units for destruction of residual contamina- tion, as well as adsorption processes to further concentrate the contaminants. Data Needs for Technology Implementation Data needs for soil washing are presented in Table 8. Table 8. Data Needs for Soil Washing. [21,22] Data Needs Possible Effects Particle size distribution Soil type Complex waste mixtures Wash solution Metal content Organic content Partition coefficient pH, buffering capacity Affects efficiency of removal from wash liquid; particles >2 inches in diameter require pretreatment for oversized particles; particles <0.063 mm in diameter are difficult to wash Affects pretreatment and transfer requirements; high clay and silt levels make it difficult to remove contaminants because of their strong adsorption to the particles Increases difficulty in formulating suitable washing fluid; solubility of different contaminants may vary Presence of surfactants or other reagents in wash solution may cause difficulties in wastewater and sludge treatment/disposal Concentrations and species affect selection of wash fluid, mobility of metals, and post-treatment Concentration and species affect selection of wash fluid, contaminant mobility and post-treatment High coefficient requires excessive volumes of wash fluid since contaminant is tightly bound Can affect pretreatment requirements, wash fluid selection, and choice of materials of construction for equipment Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- Performance Soil washing is an innovative technology available for full-scale implementation. It has been used as a remediation technology at several Superfund sites [23]. A pilot-scale soil-washing treatability study was conducted on pesticide- contaminated soil at the Sand Creek Superfund site in Commerce City, CO. The treatability study consisted of 23 individual runs conducted under varying process condi- tions. The process variables tested included: • depth of soil excavation • surfactant type and concentration * wash water temperature • pH • number of washes • liquid-to-solids ratio. Table 9 provides a summary of the treatability study results. Experimental conditions and results of the indi- vidual runs are shown in Table 10. Control runs using only ambient-temperature munici- pal water without surfactants addition demonstrated re- moval of 76 to 81 percent dieldrin and 67 to 81 percent heptachlor from the coarse soil fraction. Results indicate that surfactant addition had a positive influence on pesti- cide removal [24,25]. Table 9. Summary of Sand Creek Superfund Site Soil Washing Treatability Study Results [24]. Soil Fraction Feed Treated Coarse Treated Rnes Concentration (mg/kg) Dieldrin Heptachlor 2.7 to 27 8 to 460 0.0 to 6.8 1.4 to 50 0.0 to 37 4.4 to 340 Removal (%) Dieldrin Heptachlor NAa MA -44 to 91 17 to 99 -131 to 86 -100 to 97 BNA « Not applicable Table 10. Sand Creek Superfund Site Soil Washing Treatability Study Results'[24]. Test Conditions Run # 1 2 11 12 6 7 23 3 8 9 10 17 4 5 18 18A 19 19A 20 20A' 21 22 13 14 15 16 Surfactant Temp. none none none none 0.4A LOA LOA 0.4S LOS LOS 0.4S 0.4S 0.4T 0.5T LOT LOT L5T L5T LOT LOT 1.0M LOM LOS LOT LOT LOS ambient 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 130 pH Soil Depth (feet) 7 10 10 7 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 7 10 10 10 10 10 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1 1-3 1-3 0-5 0-5 Liq./ Soil Ratio 6:1 6:1 (9:1) 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 6:1 (9:1) (9:1) 6:1 6:1 6:1 6:1 6:1 6:1 Heptachlor (mg/kg) Feed Soil 220 87 150 170 180 230 230 100 200 270 260 22 220 220 120 120 250 250 64 64 460 210 63 120 8 12 Treated Soil 50 29 37 34 26 25 15 24 36 28 34 12 27 30 16 18 16 20 12 14 16 22 19 1.8 2.0 <1.6 Dieldrin (mg/kg) Feed Soil 19 16 24 23 17 18 18 19 17 27 25 2.8 18 20 13 16 18 18 19 19 20 17 9.7 17 2.7 3.4 Treated Soil 4.6 2.4 4.5 4.5 6.8 2.9 5.6 2.0 4.4 3.9 4.9 1.5 5.0 5.0 1.7 1.8 3.2 2.0 1.9 1.6 2.6 3.8 1.9 2.2 <1.6 <1.6 A s Adsee; S = SDS; T = Tergitol; M = SDS/Tergitol mix Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- The site cleanup criteria, established in the Record of Decision (ROD) by EPA Region VIII, were 0.55 mg/kg for heptachlor and 0.15 mg/kg for dieldrin. The analytical detection limits, 1.6 mg/kg for both contaminants, were not low enough to determine if these action levels were met [25]. This was due to matrix interferences. Bench-scale soil-washing tests conducted at the FMC Fresno Superfund site demonstrated that contaminant re- duction for any size fraction greater than 200 mesh is most influenced by the number and types of washes used. A single wash removed about 77 percent of the dieldrin from soil, but three washes using a surfactant removed 99 per- cent [26]. Additional studies at the FMC site were performed using a froth flotation wash. Data indicate that this surfac- tant-assisted wash procedure removed an average of 80 to 85 percent of the organochloropesticides (WG02 and WG03) in one wash cycle; 92 to 99 percent removal was achieved with a triple wash. Froth flotation washing removed 81 to 85 percent of the organo-phosphorus pesticides with one wash cycle [26]. High percentages of clay, silt, and humic content may have a negative effect on contaminant removal and overall volume reduction. This is because pesticides bind chemi- cally or. physically more readily to clay and silt particles. Media with high cation exchange capacity also bind some organic and organo-metallic pesticides that may be difficult to separate using this technology [17,27,28]. Process Residuals Residuals from the aforementioned process units may include oversize rocks, debris, and coarse material, air emissions, wastewater, and contaminated sludges or fines. Oversize fractions are often minimally contaminated and can be returned as backfill to the site with little or no treatment. Debris that is porous in nature, such as wood, roots, and vegetation, may be highly contaminated and require off-site disposal. Treatment units for pesticide- laden system wastewater include carbon adsorption, chemi- cal or photochemical oxidation, or biological oxidation. Con- taminated fines resulting from the soil washing subsystem can be treated either on or off site by processes such as biological or chemical oxidation, incineration or solidifica- tion/stabilization in conjunction with land disposal [16,17,18,19,20,21]. Solvent Extraction Solvent extraction is an innovative technology that uses organic solvents to extract organic contaminants from soils. Solvent extraction is mainly applicable to the decontamina- tion of soils containing volatile and nonvolatile hydrophobia organics, such as pesticides. This technology achieves volume reduction by concentrating the pesticides into an extract phase, from which the contaminants can be recov- ered, further concentrated or disposed. There are two broad categories of processes: conven- tional solvent extraction and supercritical fluid extraction. Conventional solvent extraction uses organic solvents to selectively extract the contaminants. This process may need to be repeated several times to extract the contami- nant to a certain concentration level. The solvent itself can be treated and recycled. Supercritical fluid extraction uses a highly compressed gas (e.g., carbon dioxide) above its critical temperature to perform the extraction. This highly compressed gaseous fluid can be especially useful in re- moving contaminants from interstitial spaces of the ma- trix[1,30]. Supercritical CO2 extraction is presented in a separate section. Solvent extraction technology potentially can be used for treatment of pesticides from waste groups WG02, WG03, and WG04 [29,30,31]. Process Description This process achieves volume reduction by concentrat- ing the pesticide into an extract phase. Solvent extraction typically consists of three types of subsystems: • feedstock preparation • extraction • residuals treatment/solvent recovery. As with soil washing, solvent extraction feedstock prepa- ration typically includes excavation, followed by screening operations to segregate the soil by size into highly contami- nated fines and minimally contaminated coarser soil frac- tions. This initial volume reduction can reduce the amount of soil that must be extracted, reducing the overall treatment cost. Some commercially available units treat the entire soil mass without initial volume reduction. If the soil is very wet (e.g., >70 percent moisture content), a dewatering unit is used to remove excess moisture before the extraction pro- cess [20,27,29,31,32,33]. During the soil extraction process, pesticide-contami- nated soil is mixed with an appropriate solvent in a tank- based continuous countercurrent extraction. The extraction process may require several passes to reduce the solid- phase pesticide contamination to the desired level. After extraction, the solvent extract is pumped to a sedimentation tank for removal of soil fines [20,27,29,31,32]. A suitable solvent should: have high selectivity for the contaminant(s) have high saturation solubility for the contaminant(s) be immiscible in the feed material be stable be nonreactive and noninterfering with other soil-matrix components • have favorable density, viscosity and interstitial tension properties • have a sufficiently different boiling point from the contaminant(s) to allow post-treatment separation [29,34,35]. Residuals treatment subsystems include unit opera- tions for air emission control, decontamination of the extrac- tion solvent to allow solvent recycle and removal of residual solvent from the treated soil [20,27,29,31,32,33]. Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- Data Needs for Technology Implementation Data needs and possible effects for this technology are presented In Table 11. Performance The Sanivan Group developed the Extraksol™ solvent extraction process which was used to treat PGP-contami- nated soil for the purpose of system development and demonstration of capabilities. A proprietary solvent was used In the 1-ton-per-hour pilot-scale unit. The process efficiency, presented in Table 12, was greater than 90 percent and greater than 99.7 percent, respectively, in two tests conducted on contaminated porous gravel. In addi- tion, low post-treatment POP concentrations were achieved (<0,82 mg/kg and <0.21 mg/kg). In a test on POP-contami- nated porous stones, the removal efficiency was lower, at 50 percent [32]. A bench-scale study using the B.E.S.T.™ process mar- keted by Resource Conservation Company (RCC) demon- strated a 99 percent removal efficiency for a number of pesticides !n waste groups WG02 and WG03. Data from this study is presented in Table 13. Data from other bench-scale tests using this process indicate chlordane removal efficien- cies greater than 99 percent [1]. Process Residuals Residuals include oversize materials, spent solvent, gaseous solvent emissions and treated soil. Oversize soil fractions can be returned to the site as backfill if sufficiently clean. To improve process economics, the solvent extract is generally recovered and recycled back to the extraction process. The mode of solvent recovery depends on the physical and chemical properties of the extract (solvent and contaminant). For pesticide extraction operations, distilla- tion or evaporation can be used to recover a volatile solvent from the less volatile contaminant. I n some cases, a second extraction with an aqueous solution may be the method of primary solvent recovery. The extracted soil may need treatment to remove ex- cess residual solvent. Dewatering (e.g., centrifugation), air or steam stripping, vacuum extraction, or biological treat- ment can be used to remove residual solvent from the soil. Gaseous emissions from system operations must be treated before release [20,27,29,31,32,33]. Table 11. Data Needs for Solvent Extraction. [36] Data Needs Possible Effects Complexity of waste mixture Particle size PH Contaminant size Temperature Metals Organically bound metals Detergents/emulsifiers Soli permeability Solvent characteristics Solvent extraction capacity Soil moisture content Affects solvent selection Oversize particles may require size reduction pretreatment Must be in a range compatible with extracting solvent Affects solvent selection and process efficiency; solvent extraction is least effective for very high molecular weight and very hydrophilic organics May impact solubility of contaminants in extraction solvent - this affects extraction efficiency Strong reaction may occur during treatment process because of caustic additions May be extracted along with organic pollutants and cause disposal/recycling difficulties May retain organic contaminants and reduce effectiveness of process; may cause foaming, which hinders settling and separation characteristics Affects solvent-contaminant contact; low permeability soils may require additional contact time for effective treatment May impact treatment process if nonbiodegradable, toxic, or nonvolatile Affects mass of contaminant that can be solubulized in the solvent Affects solvent-contaminant contact; soils containing more than 30 percent moisture may need to be dewatered before treatment Table 12. PCP Removal Obtained in 1 Ton/Hour Extraksol™ Pilot-Scale Solvent Extraction Unit. [32] Type of Waste Type of Solvent3 "proprietary Initial PCP Cone. (mg/kg) Final PCP Cone. (mg/kg) Removal (%) porous gravel porous gravel porous gravel #2 #2 #2 8.2 81.4 38.5 <0.82 <0.21 19.5 >90 >99.7 50 70 Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- Table 13. Pesticide Removal in Bench-Scale Study Using B.E.S.T.™ Solvent Extraction Process. [37] Analyte p,p'-DDT p,p'-DDE p,p'-DDD Endosulfan-l Endosulfan-ll Endrin Dieldrin Toxaphene BHC-Beta BHC-Gamma (Lindane) Pentachlorophenol Feedstock (ppm) 500 84 190 250 140 140 37 2,600 <30 <30 150 Product Solids (ppm) 0.2 0.5 0.05 <0.02 <0.02 0.02 <0.02 0.9 <0.13 <0.07 1.9 Removal Efficiency (% 99.96 99.40 99.97 >99.99 >99.99 99.99 >99.95 99.97 98.7 Supercritical CO2 Extraction Supercritical CO2 (SCO2) extraction is a type of solvent extraction that exploits some unique properties of supercritical fluids. Many gases, including CO2, exhibit enhanced solvent properties when compressed at condi- tions above their critical temperature (the temperature above which the gas cannot exist in the liquid state, regardless of pressure). Supercritical carbon dioxide forms when CO2 is heated and compressed above 31 °C and 1078 psi. In the supercritical state, the CO2 is not a liquid, although it exhibits liquid-like densities and displays much better solubilizing properties and mass transport characteristics than subcriti- cal, gaseous CO2. Because the supercritical fluid remains in the gaseous state, it can penetrate spaces within contami- nated soil much more readily than liquid solvents [29,30]. Several other gases such as ethylene, ethane, propane and dichlorodifluoromethanol (Soivent-12) have been tested in addition to CO2 for treatment applications of supercritical fluid extractions[29]. Process Description SCO2 extraction systems consist of an extraction vessel that can be operated at elevated temperatures and pres- sure. Carbon dioxide from a liquified bulk supply is piped to a storage vessel where it is compressed to the desired operating pressure. The pressurized CO2 is then heated to the system operating temperature and piped to the extrac- tion vessel containing the contaminated soil. After the extraction process, contaminated supercritical CO2 is piped to a separation vessel, where the pressure is rapidly re- duced, causing SCO2 to undergo phase transformation to gaseous subcritical CO2. At lower temperatures and pres- sure, the dissolved organic contaminants precipitate in the bottom of the separation vessel. Uncontaminated, gaseous CO2 is piped to the storage vessel for recycling, while the extracted organics are collected for disposal [29,30]. Data Needs for Technology Implementation Data needs for supercritical CO2 extraction are pre- sented in Table 14. Performance Supercritical fluid extraction processes have been used extensively in various applications such as decaffeinating coffee and extracting cholesterol from eggs, drugs from plants, and nicotine from tobacco [6]. The full-scale appli- cation of supercritical fluid extraction to the remediation of contaminated soils is in its infancy. Bench-scale SCO2 studies on pesticide-contaminated soil suggest that full- scale implementations will be successful [6,38]. A pilot- scale supercritical fluid system that successfully remediated PCB-contaminated sediment using a mixture of propane and butane as the extracting solvent was demonstrated by CF Systems Corporation under the SITE Program [39]. The efficiency and choice of operating conditions of SCO2 extraction systems for performing pesticide-contami- nated site soil remediations will most likely depend on the specific contaminants present. Several sets of conditions (e.g., temperature and pressure combinations) may be needed to extract soils contaminated with more than one pesticide [6,29,30,38]. Table 14. Data Needs for Supercritical CO. Extraction [6,29,38] Data Needs Possible Effects Complexity of waste mixture Contaminant polarity Soil permeability Affects temperature and pressure combinations required for effective treatment Extractive efficiency of polar pesticides may increase with the addition of an enhancer, such as methanol or acetone Affects solvent-contaminant contact; low permeability soils may require additional contact time for effective treatment Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- Process Residuals Residuals Include treated soils, recyclable CO2 gas, and liquid- or solid-phase pesticide contaminants. Decon- taminated soils can be backfilled on site. The recondensed, separated pesticide contaminants can be stabilized and disposed of In a RCRA-permitted landfill. The CO2 gas can be recycled to the extraction process [6,29,30,38]. Comparison of Option Costs, Advantages and Limitations Costs Figure 1 presents the cost ranges for the technologies discussed in this document; Table 15 lists critical factors affecting the cost ranges for the technologies discussed. Other remedial alternatives discussed in the primary refer- ence document, Contaminants and Remedial Options at Pesticide Sites, are included for comparison. This informa- tion should be used as a guide only. Specific cost estimates should be generated for each site based on specific needs and circumstances. These costs include capital operations and maintenance (O&M) costs. Advantages and Limitations Tables 16 and 17 present generalized advantages and limitations, respectively, of the treatment technologies dis- cussed. Other remedial options discussed in the primary reference are included for comparison purposes. Limita- tions specific to a technology or site application are not addressed. EPA Contact Technology-specific questions regarding remedial op- tions at pesticide sites may be directed to: Richard N. Koustas U.S. Environmental Protection Agency Risk Reduction Engineering Lab 2890 Woodbridge Avenue (MS 106) Edison, N.J. 08837 Phone: (908) 906-6898 FAX: (908) 906-6990 E-mail: Koustas.Richard@ EPAMAIL.EPA.GOV Acknowledgements This bulletin was prepared for the U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Edison, NJ by IT Corporation under Contract No. 68-C2-0108. The primary reference document, "Contaminants and Remedial Options at Pesticide Sites" [1], was prepared by Roy F. Weston, Inc. Mr. Richard Koustas served as the EPA Technical Project Monitor. This bulletin was authored by Ms. Ida Bennett, Mr. Gregory McGraw and Ms. Jennifer Platt of IT Corporation. Mr. Gregory McGraw served as Task Manager and Mr. Thomas Janszen of IT Corporation contributed his time and comments by participating in the review meetings and/or peer reviewing the document. Remediation Technologies Cost($/ton) 100 200 300 400 500 600 700 800 900 1000 Separation/Concentration Options Radio Frequency Heating Thermal Desorption Soil Washing Solvent Extraction Containment/Immobilization Options Stabilization/Solidification Vitrification (In-Situ) Destruction Options Incineration Ultra High Temperature Process Chemical Oxidation DohatogonaltoaHydrodehalogenalion Hydrolysis/Neutralization Bloremediation *No cost estimates for supercritical CO2 extraction are available blndmirat!on and vitrification costs are per cubic yard "Cost estimates ware obtained from the references provided and through contact with technology vendors Rgure 1. Available Estimated Cost Ranges for Pesticide-Contaminated Soil Remediation Technologies"'1"'0. [1,40,41] 12 Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- Table 15. Factors Affecting Cost Ranges for Technology Alternatives for Remediating Pesticide-Con- taminated Soil. technology for which) cost Incurred increased because of this factor Table 16. Advantages for Technology Alternatives for Remediating Pesticide-Contaminated Soil. Advantages Proven ability to reduce high concentrations to clean-up goals Destroys or detoxifies pesticides Can be Implemented in-silu Concentrates pesticides, reducing disposal costs Effective on some Inorganic co-contaminants 0 technology for which a specific advantage Is applicable Table 17. Limitations for Technology Alternatives for Remediating Pesticide-Contaminated Soil. High moisture content adversely affects treatment Pesticides must be destroyed by another process Produces residuals/off gases requiring treatment and/or disposal Sensitive to median particle size, pH and/or media characteristics Sensitive to co-contaminants aaaaaaanaaaaa • technology for which a specific limitation Is applicable REFERENCES 1. USEPA. 1994. Contaminants and Remedial Options at Pesticide Sites. EPA Contract No. 68-03-3482. Risk Reduction Engineering Laboratory, Washington D.C., Office of Research and Development, Cincinnati, OH, EPA 540/R-94/202. 2. Federal Insecticide, Fungicide, and Rodenticide Act, Public Law 92-516. 3. USEPA. 1988. Pesticides in Ground Water Data Base: 1988 Interim Report. Environmental Fate & Ground Water Branch, Environmental Fate & Effects Division, Office of Pesticide Programs, EPA 540-09-89- 036. 4. USEPA. 1991. FATE: The Environmental Fate Con- stants Information System Database. Environmental Research Laboratory, Office of Research and Develop- ment, Athens, GA. 5. USEPA. 1990. National Survey of Pesticides in Drink- ing Water Wells. EPA 570-9-90-015. 6. Hunter, G.B. January 1992. Extraction of Pesticides from Contaminated Soils Using Supercritical Carbon Dioxide. In Proceedings of International Workshop on Research in Pesticide Treatment/Disposal/Waste Mini- mization, T.D. Ferguson, Editor. EPA/600/9-91/047. 7. Dev, Harsh and Tom Bajzek. Hydrocarbon Removal by In Situ Heating of Soil by Electrical Energy. ITT Re- search Institute, Chicago, IL. 8. Dev, Harsh, Guggilam Sresty, and Paul Carpenter. In Situ Soil Decontamination by Radio Frequency Heating. ITT Research Institute, Tyndall Air Force Base, FL. 9. U.S. Army. November 1992. Rocky Mountain Arsenal In Situ Radio Frequency Heating/Vapor Extraction Pilot Test Report, Volume I. Document Control No. 5300-01- 12-AAFP. Rocky Mountain Arsenal, Commerce City, CO. 10. USEPA. 1991. Engineering Bulletin: Thermal Desorp- tion Treatment. EPA-540-2-91-008. Office of Emer- gency and Remedial Response, Washington D.C., Office of Research and Development, Cincinnati, OH. 11. USEPA. July 1995. Applications Analysis Report: Low Temperature Thermal Aeration (LTTA) Process, Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil 13 ------- Canonla Environmental Services, Inc. EPA/540/AR-93/ 504. Office of Emergency and Remedial Response, Washington, D.C., Office of Research and Develop- ment, Washington, D.C. 12. Roy F. Weston, IncVREAC and Foster Wheeler Enviresponse, Inc. 1993. EPA Contract No. 68-03- 3482 and 68-C9-0033. Contaminants and Remedial Options at Solvent-Contaminated Sites. Roy F. Weston, Inc., REAC, Edision, NJ. 13. USEPA. 1989. Guide for Conducting Treatability Stud- ies under CERCLA: Interim Final. EPA-540-2-89-058. Office of Emergency and Remedial Response, Wash- ington D.C., Office of Research and Development, Cin- cinnati, OH. 14. USEPA. 1994. Technology Applications Report: Low Temperature Thermal Aeration (LTTA) Process, Canonie Environmental Services, Inc. EPA/540/A5-93/ 504. Office of Emergency and Remedial Response, Washington, D.C., Office of Research and Develop- ment, Cincinnati, OH. 15. T H Agriculture & Nutrition Company, Inc. 1992. Use of Thermal Desorption for Treatment Pesticide Contami- nated Soils. Report submitted to U.S. Environmental Protection Agency, Region IV, Atlanta, GA. 16. Dennis, R.M., D. Dworkin, and W.L. Lowe. 1991. Evaluation of Commercially Available Soil Washing Pro- cesses for Site Remediation. Proceedings from Hazard- ous Material ControI/Superfund 1991, pp. 333-343. 17. Goldberg, E. 1995. German Washing Process Pulls Out Contaminants in a Rne Slurry. Soil and Groundwater Cleanup, August/September, pp. 34-37. 18. Sachse, J.D., AJ. Dietrich, D.H. Weigle, C.P. Keegan, D.C. Grant, and E.J. Lahoda. 1994. Mobile Soil Wash- Ing System. Atomwirtschaft Atomtechnik, Vol. 39, No. 3, pp. 199-201. 19. Bieber, D. and K. Crabtree. 1994. Washing Unit Chums through Diesel. Soils, November, pp. 14-17. 20. USEPA. June 1993. Applications Analysis Report: Re- sources Conservation Company B.E.S.T.™ Solvent Ex- traction Technology. EPA/540/AR-92/079. Office of Solid Waste and Emergency Response, Washington, D.C., Office of Research and Development, Cincinnati, OH. 21. USEPA. 1990. Engineering Bulletin: Soil Washing Treatment. EPA-540-2-90-017. Office of Emergency and Remedial Response, Washington, D.C., Office of Research and Development, Cincinnati, OH. 22. USEPA. 1988. Technology Screening Guide for Treat- ment of CERCLA Soils and Sludges. EPA-540-2-88- 004. Office of Solid Waste and Emergency Response, Washington D.C. 23. USEPA. September 1994. Innovative Treatment Tech- nologies: Annual Status Report, Sixth Edition. EPA 542-R-94-0005. Office of Solid Waste and Emergency Response, Washington, D.C. 24. URS Consultants, Inc., and Hazra Environmental Ser- vices, Inc. 1992. Pilot-Scale Soil Washing Study, Sand Creek Superfund Site, Commerce City, CO. Report to EPA Regions VI, VII, and VIII. 25. Frederick, R.M. and S. Krishnamurthy. 1994. Soil Washing Treatability Tests for Pesticide-Contaminated Soil. Remediation/Autumn, Vol. 4, No. 4, pp. 443-453. 26. Bechtel Environmental, Inc. 1990. "Feasibility Study for the FMC Fresno Plant Superfund Site." Report to MC Corp., San Francisco, CA. 27. USEPA. November 1989. Innovative Technology: BEST™ Solvent Extraction Process. Publication No. 9200.5-253FS. Office of Solid Waste and Emergency Response, Washington, D.C. 28. Conklin, A. 1995. Secrets of Clay: Why is it the Most Stubborn and Difficult Soil Type to Treat? Soil and Groundwater Cleanup, August/September, pp. 38-41. 29. Berkowitz, J.B. 1989. Solvent Extraction. In Standard Handbook of Hazardous Waste Treatment and Dis- posal, H.M. Freeman, editor, McGraw-Hill Book Com- pany, NY, pp. 6.77-6.90. 30. DOE. August 1993. Technical Area Status Report for Chemical/Physical Treatment, Vol. II: Supercritical Fluid Extraction. DOE/MWIP-8. U.S. Department of Energy, Office of Technology Development, Washington, D.C., pp. L-2.1-2.7. 31. DOE. August 1993. Technical Area Status Report for Chemical/Physical Treatment, Vol. II: Conventional Sol- vent Extraction. DOE/MWIP-8. U.S. Department of En- ergy, Office of Technology Development, Washington, D.C., pp. L-1.1-1.8. 32. Paquin, J. and D. Mourato. 1989. Soil Decontamination with Extraksol™. Paper presented at the 3rd Interna- tional Conference on New Frontiers for Hazardous Waste Management, Pittsburgh, PA, October 10-13. 33. USEPA. February 1995. SITE Technology Capsule: Terra-KLeen Solvent Extraction Technology. EPA540/ R-94/521a. Office of Emergency and Remedial Re- sponse, Washington, D.C., Office of Research and De- velopment, Cincinnati, OH. 34. USEPA. January 1990. Project Summary: Cleaning Excavated Soil Using Extraction Agents: A State-of-the- Art Review. EPA/600/52-89/034. Office of Emergency and Remedial Response, Washington, D.C., Office of Research and Development, Cincinnati, OH. 35. Khodacloust, A., P., J.A. Wagner, M.T. Suidan, and S.I. Safferman. Solvent Washing of PCP Contami- nated Soils with Anaerobic Treatment of Wash Flu- ids. Water Environment Research, Vol. 66, No. 5, pp.692-697. 36. USEPA. 1990. Engineering Bulletin: Solvent Extrac- tion Treatment. EPA-540-2-90-013. Office of Emer- gency and Remedial Response, Washington, D.C., Office of Research and Development, Cincinnati, OH. Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- 37. D.A. Austin. 1988. The B.E.S.T. Process - An Innova- tive and Demonstrated Process for Treating Hazardous Sludges and Contaminated Soils. Presented at 81st Annual Meeting of APCA, preprint 88-68.7, Dallas, TX. 38. Dooley, K.M., R. Gambrell, and F.C. Knopf. 1988. Supercritical Fluid Extraction and Catalytic Oxidation of Toxic Organics from Soils. In Proceedings of the Thir- teenth Annual Research Symposium, Office of Re- search and Development, Cincinnati, OH. 39. USEPA. August 1990. Applications Analysis Re- port: CF Systems Organic Extraction Process, New Bedford Harbor, MA. EPA/540/A5-90/002. Office of Emergency and Remedial Response, Washington, D.C., Office of Research and Development, Cincin- nati, OH. 40. USEPA. January 1993. Selected Alternative and Inno- vative Treatment Technologies for Corrective Action and Site Remediation. EPA/542/B-93/001. 41. USEPA. September 1994. Innovative Treatment Tech- nologies: Annual Status Report, Sixth Edition. Office of Solid Waste and Emergency Response. EPA 542-R- 94-005. Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil ------- United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 Please make all necessary changes on the below label, detach or copy, and return to the address in the upper left-hand corner. If you do not wish to receive these reports CHECK HERE [3; detach, or copy this cover, and return to the address in the upper left-hand comer.- BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 Official Business Penalty for Private Use $300 EPA/540/S-97/503 ------- |