951796 Lucia This Small Business innovative Research Phase I project evaluates the potential application of alcohol flooding for remediation of soil and ground water contaminated by lighter-than-water non-aqueous phase liquids (LNAPLs). Alcohol flooding is an innovative technique that offers the potential for enhanced levels of cleanup at a lower cost than possible with currently available technologies. Alcohols possess a great ability to solubilize petroleum hydrocarbons. Being more viscous than many petroleum-derived LNAPLs such as gasoline and aviation fuels, alcohols can mobilize LNAPLs as a pure phase by increasing viscous forces, even if the LNAPLs are not fully solubilized into the aqueous phase. Because alcohols are fully soluble with both water and LNAPLs, they partition into each phase, thereby altering the bulk liquid properties and reducing interfacial tension (IFT). As a result, viscous forces are increased and IFT is decreased, enabling enhanced LNAPL recovery to occur under realistically attainable flow velocities and gradients. Intimate contact between the alcohols and LNAPLs is essentially guaranteed under all flow conditions because both compounds are more buoyant than water and therefore accumulate in and around the water table surface. Therefore, loss of plume control will not result in the migration of contaminants out of the treatment zone. In fact, this phenomenon can work to the advantage of enhanced recovery of floating LNAPL product by injecting alcohol onto and below the water table and recovering it using a dual injection/extraction pumping scheme. Furthermore, LNAPL entrapped by capillary forces below the water table can be recovered by controlled lowering of the water table which has high concentrations of alcohol. Any residual alcohol left in the ground after the remediation effort will enhance the biodegradation of any residual LNAPL since alcohols are excellent primary substrate for in-situ biodegradation. Phase I research will confirm the feasibili ty of alcohol flooding for remediation of LNAPLs in unconfined aquifer media. A series of 10 laboratory tests in a 1 m by 1 m by 2.5 cm tank filled with fine sand will be performed to demonstrate the enhanced recovery of floating LNAPL and LNAPL emplaced below the water table using alcohols. Fluids recovered during alcohol floods will be analyzed by gas chromatography to evaluate the efficiency of the process. Remediation of LNAPL-impacted soil and ground water is an important problem at oil refineries, aviation terminals, military installations, tank farms, and other locations where hydrocarbon fuels are stored or dispensed. As alcohol is an octane enhancer, the alcohol-LNAPL mixture recovered from the subsurface has commercial value as a feedstock for refineries, thereby offsetting the cost of remediation. Therefore, this application of alcohol flooding has a significant cost savings advantage over other available technologies for LNAPL cleanup at potentially greater LNAPL recovery efficiencies.
