ORM Applications

Determination of a site specific Maximum Oil Retention (ORM) is a critical step in designing edible oil injections for optimal performance while minimizing costs.As an example, consider the design of an edible oil barrier to intercept a chlorinated solvent plume.  Site groundwater monitoring data and flow characteristics dictated a 15 ft wide by 400 ft long EOS® barrier to eliminate off-site migration.  The electron donor demand was calculated based on concentrations of groundwater contaminants (TCE, TCA, and perchlorate) and alternative electron acceptors (DO, nitrate, etc.).The next step in the process of determining the mass of oil required was to either determine a site specific ORM or estimate the ORM based on soil type.  Depending on clay content and grain size, however, oil retention on “clayey-sands” can range from 0.004 to nearly 0.01 g oil/g sediment.  If site managers had chosen to use a somewhat conservative estimate of 0.008 g oil/g sediment for the ORM, the amount of oil required would have been almost 19,000 lbs with a cost of over $62,000.  Instead, an ORM test was performed with site sediment samples and yielded a site specific ORM of 0.004 g oil/g sediment.  Based on the site specific ORM, the amount of edible oil required was approximately 9,000 lbs at a cost of just over $31,000.  Determining the ORM for this barrier resulted in a savings of over $31,000 in edible oil material costs.