Zero Valent Iron
Environmental Remediation and Restoration, In Situ Stabilization of Impacted Soils Using ZVI Addition, Former Hanley Area, St. Louis Ordnance Plant
This project was performed at the former St. Louis Ordnance Plant in St. Louis, Missouri. In Situ Stabilization (ISS) work was performed on soils that were impacted by contaminated groundwater. The treatment zone covered approximately 1,400 square feet of surface area with depths from the surface to bedrock ranging from 20 to 30 feet deep. The project goal was to mix the contaminated soils in-place with zero valent iron (ZVI). The project involved innovative means to apply the ZVI into the ground and mixing was performed in the dry, without the use of any drilling fluids. The subsequent mixture required the treatment criteria of a minimum 0.6% ZVI addition. The testing done by CH2M Hill confirmed that all soil mixed columns were in compliance with the treatment goals.
This innovative approach of dry soil mixing with ZVI is the first know full-scale application of this type.
Geo-Solutions self-performed all the soil mixing activities utilizing specialty equipment which included the soil mixing rig with a 5 foot diameter mixing tool, vapor shroud/extraction/treatment system, and ZVI injection tooling.