Fuel-Specific Bioslurper System Modifications for Enhanced Cost Effectiveness
Cost and performance rept.
ENVIRONMENTAL SECURITY TECHNOLOGY CERTIFICATION PROGRAM ALEXANDRIA VA
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Bioslurping is a demonstrated technology for removing light, nonaqueous-phase liquid LNAPL from contaminated aquifers. It combines vacuum-assisted LNAPL recovery with bioventing and soil vapor extraction SVE to simultaneously recover LNAPL and bioremediate the vadose zone. A conventional bioslurper system withdraws free-phase LNAPL from the water table, groundwater, and soil vapor in a single process stream, using the air lift created by an above ground liquid ring pump. The recovered LNAPL is separated from the groundwater and may be recycled. The recovered groundwater and soil vapor usually are treated and discharged. Because bioslurping enhances LNAPL recovery in comparison to conventional skimming and pump-drawdown technologies Place, et al. 2001, bioslurping potentially can save the U.S. Department of Defense DoD significant funds by reducing the amount of time required to remediate LNAPL-contaminated sites. At many sites, the operation of the conventional bioslurper technology results in the formation of floating solids and stable emulsions, thereby creating significant water treatment and waste handling problems. The floating solids observed at many bioslurper sites appear as a foamy mass floating at the LNAPLwater interface in an oilwater separator OWS. The floating solids are a mixture of extracted LNAPL, groundwater, soil gas, and sediment collected as part of the system process stream. The stable emulsions are suspended droplets of petroleum hydrocarbons in groundwater, which give the bioslurper process water a milky appearance. These emulsions may be produced during the mixing action of the liquid ring pump or from the slurping action within extraction wells. The floating solids and emulsions are relatively stable, and reduce the effectiveness of conventional gravity-driven OWSs. The emulsified materials may require costly downstream treatment, making full-scale implementation of the bioslurper technology less attractive.
- Economics and Cost Analysis
- Solid Wastes and Pollution and Control
- Water Pollution and Control