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 FAQs

IN-SITU VACUUM EXTRACTION PROJECTS:
1. VACUUM EXTRACTION SYSTEM DESIGN

Confidential Major Chemical Manufacturer, Texas

A major chemical company, closed two process drainage ditches as part of ongoing plant upgrade projects. The ditches were 800 and 1,200 feet long and carried waste water with high levels of chlorinated solvents. The soils in the ditches were highly plastic, saturated clays.

Analysis of soil samples indicated the presence of TCE and PCE at levels that required cleanup.

A soil vapor survey was conducted in the ditches to delineate the lateral distribution of VOCs and to evaluate the pneumatic permeability of the soils. The results of the field studies showed that vapor flow could be induced through the clay at distances adequate to capture the TCE and PCE by way of single horizontal extraction lines running the length of the impacted portions of the ditches. A remediation system including synthetic liners to prevent the inflow of either rainfall or ground water and vacuum units capable of remediating the trenches in a two year period was designed. Due to the considerable mass of TCE and PCE to be removed, the design included a granular activated carbon (GAC) vapor treatment unit with on-site regeneration.