Saltwater Remediation

SKA Consulting, L.P. was retained to investigate the extent of saltwater contamination in soil and shallow groundwater on a saltwater injection well property.  A subgrade tank at the injection well had historical releases of produced saltwater.  SKA installed 48 soil borings and 7 monitoring wells to delineate the extent of saltwater contamination.  Soil chloride concentrations were as high as 30,000 mg/kg, while shallow groundwater had chloride concentrations of up to 2,000 mg/L.  SKA prepared an Abatement Plan for submittal to the Oil Conservation Division (OCD) to excavate all contaminated soil with a chloride concentration greater than 5,000 mg/kg that was less than 20 ft below ground surface (ft-bgs), and to monitor the shallow groundwater for natural attenuation of the chloride concentrations. The soil portion of the Abatement Plan was approved by the OCD while the groundwater portion of the Abatement Plan is still under review.  SKA excavated 6,580 cubic yards of chloride-contaminated soil for off-site landfill disposal and collected 120 sidewall and bottom confirmation soil samples.  Upon completion of satisfactory confirmation sampling, SKA backfilled the excavation up to 4 ft-bgs with fill hauled back from the landfill site.   A 20-mil polyethylene liner was placed in the excavation to seal off deeper chloride-contaminated soil from rainfall infiltration.  The remainder of the excavation was backfilled with caliche to restore the well pad surface.  Groundwater monitoring of the natural attenuation of groundwater chloride concentrations is on-going.