Environmental Projects

Successful Dual Extraction and
Bioenhancement Remediation System - Texas

INNOVATIVE ENGINEERING SOLUTIONS, INC. has designed, installed and operated a bio-enhanced remediation system at a large industrial facility in Texas. The TCE, PCE and TCA plume was approximately 3,000 feet long at project inception. The remediation system consists of 36 dual extraction and bioenhancement wells; a property boundary bio-enhancement wall, and an off site bioenhancement wall. The remediation system includes groundwater and vapor phase treatment using on-site steam-regenerable granular activated carbon. The dual extraction system is removing the VOCs in the vadose zone and the dewatered soil, while the bioremediation system is remediating the portions of the saturated zone that are not dewatered. The dual extraction system was required in order to distribute amendments through the fairly low permeability silty-clay formation (as well as for volatile organic compound (VOC) mass removal). Electron donors and nutrients (lactate and molwhey) are added to the groundwater via non-pumping extraction wells to enhance anaerobic degradation of chlorinated organics.

The bioenhancement system is a state of the art automated electron donor mixing and injection system. The electron donor distribution system is coupled with a bioaugmentation delivery system that injects ethenogens (responsible for dechlorination of DCE to ethene) into the enhancement wells. Ethenogens are grown on-site in a 200-gallon reactor and are distributed to areas of the site requiring bioaugmentation.

The remediation system operated for nine years and fully remediated the 3-acre on-site plume (from hundreds of ppm to less than one ppm) and greatly improved off site conditions. Currently the remediation program consists of occasional feedings for an off-site bioenhancement trench.

To the best of our knowledge this project represents the first large full scale EAD application in the US (1997).