Steam injection combined with groundwater pumping and soil vapor extraction was demonstrated at Operable Unit One (OU-1), Hill AFB, Utah. The purposes of the research were to increase understanding of the technology and evaluate its effectiveness for cleanup of non-aqueous phase liquids (NAPLs). The results will be included in an evaluation of various technologies for potential inclusion in the OU-1 Record of Decision. Applied Research Associates, Inc. and Praxis Environmental Technologies, Inc. teamed to conduct the experiments in a 3-by-5 meter cell enclosed by steel sheet-pile walls extending into a low permeability clay layer located about 9.1 meters (30 feet) below ground surface. Constituents of the NAPL were primarily weathered fuels and oils with chlorinated solvents. Results of the steam injection test reveal very effective distillation of contaminants from the residual NAPL. Compounds of concern showed reductions in soil concentrations greater than 95% in steam-swept layers. The final groundwater concentrations in the test cell were close to cleanup levels with only two target compounds exceeding the drinking water standard. As predicted by theory, the heavy NAPL was not effectively mobilized by the steam because of its high viscosity and low residual saturation; yet the low residual saturation allowed good contact between the steam and NAPL for distillation. Estimates of the masses removed based on extracted concentrations were consistent with mass changes in the cell based on soil concentrations. An estimated total of 55 liters (14.5 gallons) of NAPL were removed from the cell. This study also employed an innovative technique known as a partitioning inter-well tracer test (PITT) to estimate the mass and spatial distribution of residual NAPL before and after the steam injection.

This report provides an engineering analysis of, and status report on, selected enhancements for soil vapor extraction (SVE) treatment technologies. The report is intended to assist project managers considering an SVE treatment system by providing them with an up-to-date status of enhancement technologies; an evaluation of each technology's applicability to various site conditions; a presentation of cost and performance information; a list of vendors specializing in the technologies; a discussion of relative strengths and limitations of the technologies; recommendations to keep in mind when considering the enhancements; and a compilation of references. The performance of an SVE system depends on properties of both the contaminants and the soil. SVE is generally applicable to compounds with a vapor pressure of greater than 1 millimeter of mercury at 20EC and a Henry s Law constant of greater than 100 atmospheres per mole fraction. SVE is most effective at sites with relatively permeable contaminated soil and with saturated hydraulic conductivities of greater than 1 x 10 or 1 x 10 centimeter per second (cm/s). SVE by itself does not effectively remove contaminants -3 -2 in saturated soil. However, SVE can be used as an integral part of some treatment schemes that treat both groundwater and the overlying vadose zone. Enhancement technologies should be considered when contaminant or soil characteristics limit the effectiveness of SVE or when contaminants are present in saturated soil. The five enhancement technologies covered in this report are as follows and are described in the following subsections: * Air Sparging * Dual-phase Extraction * Directional Drilling * Pneumatic and Hydraulic Fracturing * Thermal Enhancement.

An introduction to the principles and practices of soil and groundwater remediation Soil and Groundwater Remediation offers a comprehensive and up-to-date review of the principles, practices, and concepts of sustainability of soil and groundwater remediation. The book starts with an overview of the importance of groundwater resource/quality, contaminant sources/types, and the scope of soil and groundwater remediation. It then provides the essential components of soil and groundwater remediation with easy-to-understand design equations/calculations and the practical applications. The book contains information on remediation basics such as subsurface chemical behaviors, soil and groundwater hydrology and characterization, regulations, cost analysis, and risk assessment. The author explores various conventional and innovative remediation technologies, including pump-and-treat, soil vapor extraction, bioremediation, incineration, thermally enhanced techniques, soil washing/flushing, and permeable reactive barriers. The book also examines the modeling of groundwater flow and contaminant transport in saturated and unsaturated zones. This important book: Presents the current challenges of remediation practices Includes up-to-date information about the low-cost, risk-based, sustainable remediation practices, as well as institutional control and management Offers a balanced mix of the principles, practices, and sustainable concepts in soil and groundwater remediation Contains learning objectives, discussions of key theories, and example problems Provides illustrative case studies and recent research when remediation techniques are introduced Written for undergraduate seniors and graduate students in natural resource, earth science, environmental science/engineering, and environmental management, Soil and Groundwater Remediation is an authoritative guide to the principles and components of soil and groundwater remediation that is filled with worked and practice problems.

This book presents a comprehensive, up-to-date review of technologies for cleaning up contaminants in groundwater and soil. It provides a special focus on three classes of contaminants that have proven very difficult to treat once released to the subsurface: metals, radionuclides, and dense nonaqueous-phase liquids such as chlorinated solvents. Groundwater and Soil Cleanup was commissioned by the Department of Energy (DOE) as part of its program to clean up contamination in the nuclear weapons production complex. In addition to a review of remediation technologies, the book describes new trends in regulation of contaminated sites and assesses DOE's program for developing new subsurface cleanup technologies.

There may be nearly 300,000 waste sites in the United States where ground water and soil are contaminated. Yet recent studies question whether existing technologies can restore contaminated ground water to drinking water standards, which is the goal for most sites and the result expected by the public. How can the nation balance public health, technological realities, and cost when addressing ground water cleanup? This new volume offers specific conclusions, outlines research needs, and recommends policies that are technologically sound while still protecting health and the environment. Authored by the top experts from industry and academia, this volume: Examines how the physical, chemical, and biological characteristics of the subsurface environment, as well as the properties of contaminants, complicate the cleanup task. Reviews the limitations of widely used conventional pump-and-treat cleanup systems, including detailed case studies. Evaluates a range of innovative cleanup technologies and the barriers to their full implementation. Presents specific recommendations for policies and practices in evaluating contamination sites, in choosing remediation technologies, and in setting appropriate cleanup goals.