Ferox SM (Cr+6) Reduction (Field Application)
Based on lab treatability results, a Ferox SM field application was recently performed at Charleston Naval Yard in South Carolina. Approximately 38,000 pounds of Ferox SM powder was injected at 15 separate injection points targeting various intervals from 11 to 31 feet below ground surface.
The atomized powder slurry was injected using pressures ranging from 60 to 150 psig. During the injections, pressure response was measured in nearby monitoring wells that were screened at various depths. Pressure readings indicated that injections were influencing these wells at distances greater than 50 feet in some instances. Varying pressure readings made during injections at different depths indicated that powder was propagating horizontally outward from the injection points.
Seven of the fifteen injection points were located within an occupied historic building, which made the project both logistically and technically challenging. Computer modeling of the building structure was first performed to ensure that the building was structurally sound when subjected to even the slightest of column movements. During injections, structural columns where closely monitored to ensure that the movement criteria, as determined from the computer modeling, was not breached. In addition, crack gauges were installed on on the outside of the building to quantify any differential movement.
The field operations were scheduled in a manner as to not disrupt the day-to-day operations of the tenant within the building. Working closely with the tenant, injection points were situated between equipment inside the building. The project was completed safely and on schedule, requiring a total of 18 workdays.
Post injection groundwater sampling is scheduled for the first and second Quarter of 2002.
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