Rummaging the shelves…
Loading reviews…
This report is for ESTCP Project CU-9908. The project demonstrated and validated two innovative prepump modifications to a conventional bioslurper system: an in-well "dual drop tube" extraction system and a modified aboveground knockout tank design. These modifications are meant to reduce operation and maintenance costs associated with the simultaneous extraction of fuel with groundwater by a conventional system, which utilizes a single drop tube in-well vacuum extraction system without a prepump knockout tank. The "dual drop tube" consists of two in-well vacuum drop tubes separated by a fuel isolation sleeve, which extends 1 to 3 feet both above and below the end of the main drop tube. This tubular sleeve prevents the extraction of fuel by the main drop tube, while allowing groundwater and soil gas to enter. A smaller vacuum drop tube, located outside the sleeve, is used to remove accumulating fuel separately, using the bioslurper system pump vacuum and a separate storage vessel. Conventional systems promote extensive emulsification of fuel with groundwater and foam formation resulting from fuel-water mixtures moving through the vacuum manifold system and liquid ring vacuum pump. The "dual drop tube" and prepump knockout tank separators were operated both alone and in series at eight field sites (2- to 5-week demonstrations) and cost and performance data were obtained by a long- term demonstration (15 weeks) at NAS Fallon, Nevada. The dual drop tube separator removed all emulsions and foam and 99% of TPH from the vacuum pump discharge. Cost data are included in the report.