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The methodology, case-study examples, and recommendations described in this report are intended to provide restoration program managers, their support staff, and the regulatory community with descriptions of methods and tools that can be used to advance the state-ofpractice for monitoring and documenting the long-term sustainability of monitored natural attenuation (MNA)-based remedies for chlorinated solvent-impacted groundwater. Specifically, this report 1) presents a strategy and framework for quantitatively assessing the sustainability of MNA-based remedies for groundwater at chlorinated solvent-impacted sites, 2) provides casestudy reviews using existing long-term monitoring (LTM) data sets from multiple United States Air Force (USAF) sites where chlorinated solvents exceed closure criteria, and 3) summarizes observations and recommendations that were developed when working through the case-study examples. The context for developing this report is summarized in the following general observations from a review of data from multiple USAF sites where MNA is either a primary or secondary remedy component for remediation of chlorinated solvents in groundwater.

This study evaluates whether monitoring wells installed using direct-push techniques (DPT) provide ground water chemical data of comparable quality to conventionally-installed wells for evaluation and performance monitoring of monitored natural attenuation (MNA) of dissolved volatile organic compounds (VOCs). Data evaluation methods included statistical and qualitative analyses performed on existing data sets from multiple United States Air Force facilities. Study results provide strong evidence that DPT and conventional wells can be used interchangeably for monitoring MNA of chloroethenes and evaluating local redox conditions. Results are inconclusive on the interchangeable use of DPT and conventional wells for MNA monitoring of dissolved petroleum hydrocarbons, as petroleum hydrocarbon concentrations in DPT wells generally were observed to be higher than concentrations measured in conventional wells. The findings of this study are relevant to monitoring activities at Department of Defense facilities because DPT techniques may allow faster and less expensive well installation, relative to conventional techniques, at shallow (<50-foot) and, in some lithologies, intermediate (50- to 100-foot) depths., The original document contains color images. Sponsored in part by Defense Logistics Agency.The original document contains color images.

This technical guidance document provides site remediation managers, technical support staff, and the regulatory community with information on how to 1) assess natural attenuation processes and 2) incorporate the results of this assessment into remedy planning and implementation efforts. This document serves as an addendum to the Technical Protocol for Implementing Intrinsic Remediation with Long-Term Monitoring for Natural Attenuation of Fuel Contamination Dissolved in Groundwater (Air Force Center for Environmental Excellence AFCEE, 1995). The original protocol (AFCEE, 1995) is to be retained, with this addendum serving to complement the original protocol by providing expanded guidance on developing and implementing expedited closure plans and formal exit strategies for fuel-release sites., The original document contains color images. Sponsored in part by Defense Losistics Agency, Fort Belvoir, VA. Task Order 0024.

Under contract to AFCEE, Parsons ES collected cost and performance data to determine the applicability of using flameless thermal oxidation (FTO) technology for treatment of extracted soil vapors containing chlorinated and non-chlorinated volatile organic compounds (VOCs) at three Air Force sites.

The Air Force Center for Environmental Excellence (AFCEE) has sponsored an ongoing program to promote the use of cost-effective soil vapor treatment technologies in conjunction with soil vapor extraction (SVE) for remediation of fuel- and solvent-impacted sites. On September 20, 1995, Parsons Engineering Science, Inc. (Parsons ES) received formal notice to proceed from HSD/PKVDA at Brooks Air Force Base (AFB) under Contract F41624-94-D-8136, Delivery Order 28, to implement a statement of work (SOW) that outlines requirements to provide services to support environmental air conformity through evaluation of the flameless thermal oxidation (FTO) vapor-phase treatment technology for SVE off-gas abatement at various Air Force base sites worldwide. Thermatrix, Inc. (Thermatrix) of Knoxville, Tennessee is an AFCEE directed subcontractor providing the FTO treatment system to be evaluated during the demonstrations. Thermatrix was selected in the Broad Agency Announcement (BAA) for Technology Demonstration for technology evaluation and cost performance of their GS Series FTO system. A technology demonstration was designed by Parsons ES to determine the applicability of using FTO technology for treatment of extracted soil vapors containing chlorinated and non-chlorinated volatile organic compounds (VOCs). Three Air Force installations were identified for demonstrating the FTO system, including Building 181 at AFP 4, Fort Worth, Texas, which is the subject of this report.

The Air Force Center for Environmental Excellence (AFCEE) has sponsored an ongoing program to promote the use of cost-effective soil vapor treatment technologies in conjunction with soil vapor extraction (SVE) for remediation of fuel- and solvent-impacted sites. On September 20, 1995, Parsons Engineering Science, Inc. (Parsons ES) received formal notice to proceed from HSD/PKVDA at Brooks Air Force Base (AFB) under Contract F41624-94- D-8136, Delivery Order 28, to implement a statement of work (SOW) that outlines requirements to provide services to support environmental air conformity through evaluation of the flameless thermal oxidation (FTO) vapor-phase treatment technology for SVE off-gas abatement at various Air Force base sites worldwide. Thermatrix, Inc. (Thermatrix) of Knoxville, Tennessee is an AFCEE-directed subcontractor providing the FTO treatment system to be evaluated during the demonstrations. Thermatrix was selected through the Broad Agency Announcement (BAA) that included demonstrations for evaluation of cost and performance of their GS Series FTO system. A technology demonstration was designed by Parsons ES to determine the applicability of using FTO technology for treatment of extracted soil vapors containing chlorinated and non-chlorinated volatile organic compounds (VOCs). Three Air Force installations were identified for FTO system demonstrations, including the Source Area Reduction System (SARS) at the former Lowry AFB, Colorado. The results of the FTO system demonstration at the SARS are summarized in this report.

The SVE and vapor-phase treatment demonstration was performed at Plattsburgh AFB, New York, Site FT-002, from August 27, 1996 through March 25, 1997. The technology demonstration was conducted over a 30-week period, and soil vapors were extracted from 14 site wells. The FTO system was tested using individual wells, or pairs of wells for a period of up to 2 weeks per well (or well pair) to determine the optimum vacuum/extraction flow rate balance among all wells and soil vapor concentrations from each of the wells. The 30-week demonstration served two primary purposes: 1) evaluation of the FTO technology, and 2) collection of test data to support the design and operation of a full-scale SVE system that was installed at Site FT-002 by OHM Remediation Services, Inc. (OHM) in 1996. The FTO technology demonstration was performed in accordance with the Final Work Plan for the Evaluation of Flameless Thermal Oxidation at Plattsburgh Air Force Base (the work plan) (Parsons ES, 1996a), and the Addendum to the FTO work plan (Parsons ES, 1996c). The purpose of the site-specific technical report is to evaluate the effectiveness of the FTO system during the Site FT-002 field demonstration and to summarize FTO system performance, operational costs and reliability, and evaluate full-scale treatment system application for the site FT-002.

During early February of 1990, a ruptured pipe at a Burlington Northern Railroad (BNRR) fueling pumphouse in Alliance, Nebraska resulted in over 60,000 gallons of No. 2 diesel fuel spilling onto the surrounding soil. Several months later, a subsurface investigation indicated that soils were contaminated to a depth of over 65 feet below ground surface (bgs) and were in a position to impact groundwater, which was observed approximately 70 feet bgs. State regulatory agencies requested that BNRR develop and implement a remedial action plan to treat these diesel-contaminated soils and protect local groundwater. Parsons Engineering Science, Inc. (Parsons ES) was retained for this work and, after evaluating a variety of remediation technologies, recommended using soil bioventing methods to begin the removal of volatile benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds and the long-term biodegradation of all fuel residuals. Parsons ES first designed and implemented a bioventing pilot test to determine soil properties such as air permeability, and to assess the potential for both volatilization and long-term biodegradation of diesel fuel residuals at the site. Pilot test results confirmed that bioventing was feasible for the remediation of this site, and a full-scale bioventing system was installed on the site in September 1991. This system has operated continuously for over 4 years. BNRR personnel have been responsible for weekly system checks, and Parsons ES has been responsible for semi-annual respiration testing and for soil sampling to determine the level of cleanup achieved during the first 4 years of in situ bioventing. This document summarizes the work completed to date and the 4-year findings of this innovative technology demonstration., Presented at Workshop on Tri-Service Environmental Technology held in Hershey, PA on 20-22 May 1996. Pub. in Proceedings of the Tri-Service Environmental Technology Workshop, p205-217, May, 1996. This article is from ADA429790 Proceedings of the Tri-Service Environmental Technology Workshop, "Enhancing Readiness Through Environmental Quality Technology" Held in Hershey, PA on 20-22 May 1996

A low-cost and innovative soil vapor extraction (SVE) system using modified internal combustion engines (ICEs) to extract and destroy fuel hydrocarbons is successfully remediating a large JP-4 jet- fuel-contaminated site on Davis-Monthan Air Force Base (DMAFB), Arizona. Based on previous site investigations, soil contamination extended from near the ground surface to a depth of approximately 260 feet below ground surface (bgs). A maximum total fuel hydrocarbon concentration of 320,000 milligrams per kilogram (mg/kg) and a maximum soil gas hydrocarbon vapor concentration of 140,000 milligrams per liter (mg/L) were measured at the site. Prior to installing the full-scale SVE system using the ICE technology, bioventing and SVE with thermal oxidation were evaluated and determined not to be cost effective technologies for this site. In 1994 Parsons Engineering Science, Inc. (Parsons ES), under contract with the Air Force Center for Environmental Excellence (AFCEE), conducted an SVE pilot test to collect cost and performance data on the ICE technology and to provide recommendations for the full-scale SVE system design. A full-scale SVE system using two 460-cubic-inch engines is now operating at a total volatile organic compound (VOC) removal rate of approximately 2,200 pounds per day, with a destruction efficiency exceeding 99.9 percent., Presented at Workshop on Tri-Service Environmental Technology held in Hershey, PA on 20-22 May 1996. Pub. in Proceedings of the Tri-Service Environmental Technology Workshop, p267-273. This article is from ADA429790 Proceedings of the Tri-Service Environmental Technology Workshop, "Enhancing Readiness Through Environmental Quality Technology" Held in Hershey, PA on 20-22 May 1996

A technology demonstration was designed by Parsons Engineering Science, Inc. (Parsons ES) to determine the applicability of using flameless thermal oxidation (FTO) to treat extracted chlorinated volatile organic compound (VOC) soil vapors, primarily trichloroethene (TCE). The soil vapor extraction (SVE) and treatment demonstration was to be performed at Building 181, Air Force Plant 4 (AFP 4), in Fort Worth, Texas. Building 181 was previously investigated by other contractors to characterize the effects of subsurface solvent releases that were detected in 1991. This FTO treatment technology demonstration was attempted at Site 181 from 16 March through 30 April, 1996, as part of an ongoing innovative technologies evaluation program sponsored by the US Air Force Center for Environmental Excellence (AFCEE) in order to promote cost-effective vapor treatment technologies at fuel- and solvent-contaminated sites. The technology demonstration was to have been performed in accordance with the Final Work Plan for the Evaluation of Flameless Thermal Oxidation at Air Force Plant 4 (AFP 4), Fort Worth, Texas (Parsons ES, 1996), as approved by the Air Force and regulatory agencies.

This technology demonstration was completed to determine the feasibility of using an ultraviolet (UV) oxidizing catalyst in the presence of ozone to treat non-chlorinated, fuel hydrocarbon volatile organic compounds (VOCs). The soil vapor extraction (SVE) and treatment demonstration was conducted at the Installation Restoration Program (IRP) Site SS-20 located at Myrtle Beach Air Force Base (AFB), Myrtle Beach, South Carolina. Site SS-20, locally known as the MOGAS site, was previously investigated under the IRP and known to be contaminated with gasoline residuals. This demonstration was conducted from 10 November to 20 December 1996 and was performed as part of an ongoing innovative technologies evaluation program sponsored by the Air Force in order to promote cost-effective vapor treatment technologies at contaminated sites. The technology demonstration was performed in accordance with the 'Treatability Study Test Design for ULTROX(registered) UV/Oxidation System Pilot Scale Treatability Testing at Myrtle Beach AFB, Myrtle Beach, SC.' (Zimpro, ULTROX Division, September, 1995) as approved by the Air Force and regulatory agencies.

This document describes the performance and costs associated with the Purus PADRE(registered) vapor treatment system manufactured by the Purus Corporation of San Jose, California (Purus Inc. 2713 N First Street, San Jose, CA 95134-2000). During the period of 11 February to 1 June 1994, a Purus PADRE(registered) Model 1.6 was tested at the Vandenberg Air Force Base (AFB) Base Exchange (BX) service station near Lompoc, California. In many states, VOCs must be treated before being discharged into the atmosphere. In the Santa Barbara Air Pollution Control District, discharges of both total VOCs and benzene are regulated. The Purus PADRE(registered) system was selected to provide treatment of these compounds until vapor concentrations were reduced to acceptable levels. The test was completed in conjunction with an ongoing bioventing pilot test conducted by Parsons Engineering Science, Inc. (Parsons ES) under the direction of the Air Force Center For Environmental Excellence (AFCEE), Technology Transfer Division (ERT). The purpose of this test was to independently measure both the performance and the cost of Purus PADRE(registered) operation, and to determine how this technology can be most effectively used to complement the bioventing technology.