Representative Soil Mixing Projects

In-Situ Fixation, Inc. has successfully completed several successful soil remediation projects utilizing our Dual Auger® Technology. A brief description of representative in-situ soil mixing projects is given below.

Solidification/Stabilization Low-Level Radioactive Soil
Department of Energy, Savannah River Site, Aiken, South Carolina, 2002

I-SF recently completed two (2) separate contracts at DOE's Savannah River Site. Each project involved the solidification and stabilization of unlined earthen wastewater basins located adjacent to nuclear reactors. Both K-Area Reactor Seepage Basin and C-Area Reactor Seepage Basin contained low-level radioactive contaminated soils. The Dual Auger® was used to thoroughly mix a pozzalanic grout blend (cement/bentonite) into the contaminated soils. The soil type within the basins varied from sandy clay to stiff clay and by utilizing the versatility of the Dual Auger® ,different injection and mixing rates were used to efficiently treat the different soil types and at the same time meet or exceed the performance requirements. I-SF developed a special grout mixing and dispensing system to accommodate the viscous grout blend necessary to meet theDual Auger® production capacity. Upon completion of the S/S mixing operations, I-SF installed an impermeable soil cap over each basin. In addition to the Soil Mixing Operation, I-SF solidified two contaminated piplines that conveyed the wastewater from the reactors to the basins and designed and constructed two large waste trenches for the containment of secondary low-level radioactive wastes.

Soil Mixing Thermally Enhanced Soil Vapor Extraction, Fe0 Injection
Argonne National Laboratory-East, (ANL-E) - Argonne, Illinois, 1998

Argonne National Laboratory-East (ANL-E) decided to perform a voluntary interim corrective action to remove chlorinated volatile organic compounds, (Cl VOCs), (the majority of the contamination) and non-chlorinated VOCs from an inactive waste disposal area. The project goals were to remove the majority of the VOCs from selected highly contaminated areas with the intent that the surrounding lightly contaminated, larger area could be treated by another approach at a later date. A two (2) step treatment approach was selected. The primary method of soil treatment was Soil Mixing utilizing Hot Air/Steam, also referred to as Soil Mixing Thermally Enhanced Soil Vapor Extraction (SM/TESVE). This technology was chosen because the soils are glacial till (stiff clay) with very low permeability. The secondary method chosen was Zero Valent Iron Injection (Fe0) by Soil Mixing. After employing this two step method, Air/Steam followed by Iron Injection for a short period, I-SF developed an installation technique, whereas Hot Air/Steam and Iron were injected simultaneously, thus eliminating the costs associated with the additional application and reducing the project length. The clean-up results showed removal rates of the Cl VOCs in excess of 95%. This was the first application of auger mixing and injecting Zero Valent Iron fillings/powder into the soil, at depth over a large area, ever performed in the Industry.

Soil Mixing Thermally Enhanced Soil Vapor Extraction
Lockheed Martin Specialty Components (LMSC), - Pinellas, Florida, 1997

This I-SF project was to demonstrate the applicability of Soil Mixing/Thermally Enhanced Soil Vapor Extraction (SM/TESVE) for removal of VOCs from sandy soil, below the water table. The major compounds of concern, were methylene chloride, trichloroethylene, toluene, vinyl chloride and cis 1,2-dichloroethylene. The majority of the contamination was located in an area, hot spot, approximately 56' x 60', where concentrations reached over 6000 ppm. Other areas of the site had lower but still significant concentrations: i.e. 100 ppm of total VOCs. For this project, I-SF designed and built a specialized auger configuration and a complete process system, which could destroy up to 60 lb./hr of chlorinated VOCs. The final results were very positive. Large amounts of VOCs were removed from both the DNAPL hot spot and the surrounding less contaminated areas. The equipment processed up to 75 lb./hr VOCs at greater than 95% destruction efficiency in the off-gas stream. New methods of operational controls were developed, so that when within the hot spot area the Process System could be periodically operated above its maximum design capacity of 60 lb./hr. The success of the LMSC project clearly indicated that the I-SF Dual Auger¨ can remove large concentrations of VOCs very efficiently.

Bio-Remediation of Diesel and Waste Oil Sites, Deep Soil Mixing
Seabury Chevrolet, - Yuma Arizona, 1996

Two (2) sites were remediated at the same facility, but at different locations. One site was contaminated with diesel fuel and the other was contaminated with waste oils. The contamination range exceeded 35,000 ppm to a depth of forty-five (45) feet. The soil characteristics were nearly identical at both sites, in that the top twenty five (25) to twenty seven (27) feet was a tight, dense sandy/silty layer over a damp tight clay layer, ten (10) to twelve (12) feet thick. The heaviest concentration of contamination laid in the twenty five (25) to thirty-five (35) foot zone. This was the first successful commercial application of deep in-situ soil bio-remediation, utilizing a soil mixing technology in the United States.

The remediation method utilized was the injection and mixing of bacteria and nutrients (reagents) into the soil to a depth of forty-five (45) feet using I-SF's Dual Auger®. The reagents were injected on the down stroke and air was injected on the up stroke. The reagent delivery system I-SF has developed allows for a variable reagent injection rate. The type of reagents, volume of reagents and location of injection into the soil can be adjusted as the treatment of the cell progresses. Even at a depth of between thirty five (35) and forty (40) feet in a clay soil, the I-SF Dual Auger® equipment broke the soil up so well that air bubbles and diesel vapors were passed to the surface while the air injection rates were at only 75-100 CFM. Periodic sampling and analytical testing revealed a diminishing trend in the contaminant concentrations. The analytical results at the diesel site at 120 days showed the highest remaining diesel constituent concentration to be below 500 ppm. The waste oil site at 90 days showed the highest waste oil constituent concentration to have been reduced to 6500 ppm. Both sites have been deemed closed by the Arizona Department of Environmental Quality (ADEQ).

Soil Vapor Extraction and Off-Gas Treatment of Volatile Organic Compounds
Arizona, 1996

I-SF has successfully completed two soil remediation projects that primarily dealt with the off-gas treatment consisted of heavy concentrations of Volatile Organic Compounds (VOCs).

The innovation in the first project, was the development and use of a low inlet flow blower and condensation/separator system for the in-situ soil treatment. The remedial action addressed BETX contaminated soil. Due to lower emission standards (rural location), I-SF was able to design and maintain a system that allowed for the direct discharge to the atmosphere, thus eliminating the cost of an off-gas treatment system.

The second project addressed was a heavily contaminated soil laden with heavy BTEX concentrations. The project required the utilization of a medium (approx. 200 CFM) capacity thermal oxidation unit, as part of the off-gas treatment system. Special attention was paid in the detailed electronic monitoring (manual and automatic) necessary for the system operation. Continual monitoring and adjustment kept the input gases balanced with the Lower Explosive Limits (LEL) of the thermal oxidizer, thus safe operating conditions. I-SF modeled and developed a dilution air inlet system that interfaced with the monitoring devices in the inflow stream, which contained varying VOC concentrations, allowing for a continual system operation.