Gasoline plume

FIGURE 18.5 Using overlapping cones of influence to contain a gasoline plume. 

Dual-pump systems are better able to control a constant cone of depression than the singlepump system. It is important to maintain a nearly constant cone of depression to prevent the migration of the gasoline plume. If a constant cone of depression is not maintained, the water table and... 

Under optimum conditions, an oil-water separator can reduce the hydrocarbon emulsion in water down to 15 mg/L. The separator is most effective when the gasoline plume is relatively small and the rate of water flow is slow enough to allow for complete separation. 

Schirmer M, Molson JW, Frind EO, Barker JF (2000) Biodegradation modeling of a dissolved gasoline plume applying independent laboratory and field parameters. J Contam Hydrol 46 339-374... 

Case Studies of MTBE/Gasoline Plumes in Maine (Garrett et al.,... 

Groundwater contaminant plumes from accidental gasoline releases often contain methyl-tert-butyl ether. Experiments with certain soil microorganisms showed that a culture able to degrade methyl-tert-butyl ether did not degrade benzene and toluene. Further interactions were observed [468]. 

Migration of the gasoline free product and the contaminated groundwater plumes should be controlled. The containment of a plume prevents its further migration and the enlargement of contaminated areas. The most effective method is to pump so as to cause a depression of the water... 

Gathering and extracting (associated with gasoline/water separators) the contained plume from underground... 

Installation of the pumping well is more time consuming than digging a trench. There is a lag period between the start of pumping, the formation of the depression cone, and containment of the plume. This limits its use as a rapid containment measure. The water table depression must be kept constant otherwise, if the water table is allowed to fluctuate, gasoline droplets may adhere to soil particles and get trapped below the water table, especially when the depth of the cone of depression gets lower. 

Electron donors—In direct biodegradation pathways, the contaminant acts as the electron donor or substrate. However, during cometabolic degradation, a different electron donor is metabolized, resulting in the consequential oxidation of the contaminant. In some contaminated plumes, other electron donors, such as other constituents of gasoline, may also be present. In cases where they are not, and cometabolic degradation pathways are desired, electron donors may be added. 

With spills of MTBE containing gasoline, three plume types depending on the time of the spill event can be differentiated in groundwater (Fig. 5) ... 

Type 1 Young gasoline spill MTBE plume spreading corresponds to that of the BTEX... 

Type 3 Old gasoline spill MTBE plume torn off from the source area and MTBE downstream spreading from the source whereas the BTEX pliune is developed further upstream... 

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