ORIN’s approach to free product removal utilizes chemical injection and simultaneous vacuum extraction from drilled extraction wells, and/or monitoring wells.
Injection delivers a preferred treatment chemistry through a series of borings spaced in a grid-like pattern. The treatment chemistry is injected into the rods and delivered to the surrounding formation. The typical treatment chemistries are oxidants and catalysts which have surfactant-like properties when initially injected, flushing and desorbing contaminant mass from the soils for enhanced recovery. Also, the oxidant treatment chemistry remains active and continues to degrade the contaminant following the free product removal event.
Extraction recovers the free product via screened wells.
A dip leg or “stinger” is placed down the well and connected to a vacuum extraction truck. The extraction wells draws in treatment chemistry from adjacent injection points providing hydraulic control and more precise placement of injected chemicals. Contaminant mass is desorbed as the chemistry is drawn through the subsurface, allowing the mobilized contaminant to be more easily recovered via vacuum extraction.
To further maximize the enhanced product recovery created by the surfactant effect, injection and extraction rates are coordinated to create cones of impression and depression. Cones of impression allow the treatment chemistry to influence the smear zone, enabling desorption and subsequent recovery of contaminants held in the smear zone. Cones of depression occur while treatment chemistry is being drawn at a higher rate toward the extraction well. This allows for the chemistry to contact the largest area possible, enabling more efficient product recovery.