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In-Situ Chemical Treatment/Oxidation

Jefferson, OH: Shallow Soil Mixing


Geo-Con was contracted to soil mix approximately 1,200 Cubic Yards of contaminated soil at a site in Jefferson, Ohio.

The contaminated soils were located along the west side of the building and under the existing parking lot and extended through a soil/weathered shale layer from approximately 9-feet below existing ground surface to a competent shale layer located between 16 and 18-feet below ground surface. The contamination plume was a result of past manufacturing activities at the site. The site was already being remediated by a combination of natural degradation and collection/treatment via a small onsite treatment plant consisting of pumping and air-stripping apparatus, however due to the low permeability of the weathered shale, the current methods were not accomplishing the required degradation/removal within the desired time-frame.

To accelerate the natural microbial degradation of the contamination already taking place, the Volatile Organic Chemical (VOC) contaminated soils were mixed with Emulsified Soybean Oil and Vitamin B-12 supplements. Due to the extremely high blow-counts exhibited by the weathered shale layer, Geo-Con selected the excavator method of shallow soil mixing to blend the contaminated soils with the organic substrate. The top 9 feet of overburden material was removed and staged near the mixing area. The underlying soils were mixed in 15-foot by 10-foot cells. A water-oil emulsification was produced in Geo-Con's Chem-Grouter Batch Plant and pumped to the mixing cells where it was blended by the excavator with the site soils to distribute the oil mixture evenly. Upon completion of the mixing activities, the soils were compacted via excavator and excess overburden material was removed to a GE approved landfill. A 3-inch layer of stone was placed over the compacted soils when the project was complete.

Challenges of this project included restricted working hours as the project location was in a residential neighborhood, mixing around an existing sewer pipe, and working within 2 feet of the existing building.

The project was completed within budget and ahead of schedule and with no health and safety related incidents and no damage to the private property either on or near the site.


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