Oxygen groundwater sparging

An important innovation in bioremediation technology has been the use of air sparging to oxygenate groundwater. A typical system is presented in Figure 14.6. Using this technique, the removal of contaminants is achieved using two simultaneous mechanisms ... 

The relatively low Henry s constants (the ratio of a compound s concentration in air relative to its concentration in water) of oxygenates can result in them being more difficult to strip from contaminated groundwater via air sparging or air stripping as part of a pump-and-treat remedy. 

The treatment performance data for 123 projects show that air sparging (either alone or in combination with other technologies) has been used to reduce MTBE in groundwater from concentrations >1,000,000 to <50 pg/L. The median project duration for the 19 completed sites ranged from 1 to 5 years. Although two of the 123 projects listed TBA as a cocontaminant, neither of these projects reported TBA concentrations before or after treatment no data for other fuel oxygenates were reported. 

The simulated groundwater used in these experiments was prepared to represent the compositon of groundwater from Well DC-6, Grande Ronde Formation, which samples water primarily from 200 m below the Umtanum unit on the U S DOE Hanford site near Richland, WA (1) Its composition is shown in Table II The groundwater used in these experiments was continually sparged with N2 gas before it entered the apparatus to reduce the dissolved oxygen level and to limit CO2 pickup ... 

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