Air Sparging Pilot Study Case History

Air sparging was used to perform a pilot test at an audio equipment manufacturing facility. The release site was an open nearby area where paint shop wastes had been discharged into the subsurface via a dry well over a 9-year period. Previous initial studies confirmed organic and inorganic contaminants in soil and groundwater. 

In all, 11 vertical soil vapor extraction wells and 9 vertical air sparge wells were installed in the treatment area. Sand chimneys (boreholes filled with coarse sand) were also installed to facilitate vertical air circulation. Mechanical remediation equipment and systems control installed for remediation were mosdy automated with minimal operator control required. 

The preliminary study identified approximately 2300 yd3 of contaminated soil with a hot zone of approximately 800 yd3, which required the bulk of remediation effort. A pilot air sparge/soil vapor extraction study was made to define remediation costs. The remediation effort was estimated to extend for 3 years. 

The cost projections are based on assumptions and costs developed from pilot test data. The 12 categories defined to reflect the cleanup activities are as follows  

The itemized costs for each of these categories on a year-by-year basis for an estimated 3-year operating life is shown in Table 11.3. The total cost to remediate 21,300 yd3 of soil was estimated to be 220,737 or 10.36/yd3. This figure does not include any treatment of the off-gases. If effluent treatment costs are included, it would increase costs to 385,237 or 18.09/yd3. 

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