JV Task 59-Demonstration of Accelerated In Situ Contaminant Degradation by Vacuum-Enhanced Nutrient Distribution

The Energy & Environmental Research Center (EERC) conducted remediation of hydrocarbon-contaminated soils and groundwater at a former Mohler Oil site in Bismarck, North Dakota. The remedial strategy was based on the application of two innovative concepts: (1) design and deployment of the mobile extraction, treatment, and injection units to overcome site limitations associated with urban settings in high-traffic areas and (2) vacuum-controlled nutrient injection within and on the periphery of an induced hydraulic and pneumatic depression. Combined contaminant recovery since the beginning of the project in June 2003 totals over 13,600 lb ({approx}6,170 kg) of hydrocarbons, equivalent to 2176 gallons (8236 l) of product. In situ delivery of 1504 Ib (682 kg) of ionic nitrate and 540 Ib (245 kg) of dissolved oxygen translates into further reduction of about 489 Ib (222 kg) of benzene for the same period and provides for long-term stimulation of the natural attenuation process. In addition to contaminant recovered by extraction and reduced by in situ biodegradation, a total of 4136 Ib (1876 kg) of oxygen was delivered to the saturated zone, resulting in further in situ reduction of an estimated 1324 lb (600 kg) of dissolved-phase hydrocarbons. Based on the results of the EERC demonstration, the North Dakota Department of Health approved site abandonment and termination of the corrective action

JV Task 99-Integrated Risk Analysis and Contaminant Reduction, Watford City, North Dakota

The Energy & Environmental Research Center (EERC) conducted a limited site investigation and risk analyses for hydrocarbon-contaminated soils and groundwater at a Construction Services, Inc., site in Watford City, North Dakota. Site investigation confirmed the presence of free product and high concentrations of residual gasoline-based contaminants in several wells, the presence of 1,2-dichloroethane, and extremely high levels of electrical conductivity indicative of brine residuals in the tank area south of the facility. The risk analysis was based on compilation of information from the site-specific geotechnical investigation, including multiphase extraction pilot test, laser induced fluorescence probing, evaluation of contaminant properties, receptor survey, capture zone analysis and evaluation of well head protection area for municipal well field. The project results indicate that the risks associated with contaminant occurrence at the Construction Services, Inc. site are low and, under current conditions, there is no direct or indirect exposure pathway between the contaminated groundwater and soils and potential receptors

MERCURY RELEASE FROM DISTURBED ANOXIC SOILS

The primary objectives of experiments conducted at the Energy & Environmental Research Center (EERC) were to provide information on the secondary release of mercury from contaminated anoxic sediments to an aqueous environment after disturbance/change of in situ physical conditions and to evaluate its migration and partitioning under controlled conditions, including implications of these processes for treatment of contaminated soils. Experimental work included (1) characterization of the mercury-contaminated sediment; (2) field bench-scale dredging simulation; (3) laboratory column study to evaluate a longer-term response to sediment disturbance; (4) mercury volatilization from sediment during controlled drying; (5) resaturation experiments to evaluate the potential for secondary release of residual mercury after disturbance, transport, drying, and resaturation, which simulate a typical scenario during soil excavation and transport to waste disposal facilities; and (6) mercury speciation and potential for methylation during column incubation experiments

SUBTASK 7.2 GLOBAL WARMING AND GREEHOUSE GASES

Evaluation of current climatic trends and reconstruction of paleoclimatic conditions for Devils Lake have been conducted based on diatom-inferred salinity for the last 2000 years. The 3-year cross-disciplinary research, funded by the U.S. Department of Energy (DOE) was carried out by the Energy & Environmental Research Center (EERC) and St. Croix Watershed Research Station (SCWRS) at the Science Museum of Minnesota. The results indicate that frequent climatic fluctuations resulting in alternating periods of drought and wet conditions are typical for the northern Great Plains and suggest that the severity and length of extremes exceeded those on modern record. Devils Lake has experienced five fresh periods and two minor freshening periods in the last 2000 years. Transitions between fresh and saline periods have been relatively fast, representing lake level changes that have been similar to those observed in the last 150 years. From 0 to 1070 A.D., Devils Lake showed more variable behavior, with fresh phases centered at 200, 500, 700, and 1000 A.D. From 1070 A.D. to present, Devils Lake was generally saline, experiencing two minor freshening periods at 1305-1315 and 1800-1820 A.D and the major current freshening from 1960 A.D. to present

JV Task-130 Technological Synergies for Recovery of Organic Pollutants from a Coal Seam at Garrison, North Dakota

The Energy & Environmental Research Center (EERC) initiated remediation of hydrocarbon-contaminated soils and groundwater associated with gasoline release at the Farmers Union Oil station in Garrison, North Dakota. The remedial strategy implemented is based on application of two innovative concepts: (1) simultaneous operation of soil vapor and multiphase extraction systems allowing for water table control in challenging geotechnical conditions and (2) controlled hot-air circulation between injection and extraction wells to accelerated in situ volatilization and stripping of contaminants of concern (COC) alternatively using the same wells as either extraction or injection points. A proactive remedial approach is required to reduce high COC levels in the source and impacted areas and to eliminate long-term health risks associated with contaminant migration to water-bearing zones used as a regional water supply source. This report compiles results of Phase I focused on design, construction, and start-up of remediation systems

Subtask 2.4 - Integration and Synthesis in Climate Change Predictive Modeling

The Energy & Environmental Research Center (EERC) completed a brief evaluation of the existing status of predictive modeling to assess options for integration of our previous paleohydrologic reconstructions and their synthesis with current global climate scenarios. Results of our research indicate that short-term data series available from modern instrumental records are not sufficient to reconstruct past hydrologic events or predict future ones. On the contrary, reconstruction of paleoclimate phenomena provided credible information on past climate cycles and confirmed their integration in the context of regional climate history is possible. Similarly to ice cores and other paleo proxies, acquired data represent an objective, credible tool for model calibration and validation of currently observed trends. It remains a subject of future research whether further refinement of our results and synthesis with regional and global climate observations could contribute to improvement and credibility of climate predictions on a regional and global scale