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| Following is a question Initiatives
received from a reader. If you have questions, enter them
on the Reader Service Card
and we'll answer, or find experts to answer, your
questions in future issues of Initiatives. Does surfactant remediation work against chlorinated solvents? University of Texas says yes, but Mark Hampton of the U.S. Army Environmental Center says no. Tom Gerard Surfactant-enhanced remediation can be successfully used in conjunction with a pump-and-treat system to dissolve and remove chlorinated solvents. However, certain site conditions can complicate the remediation where fractured rock or clay prevail. In these cases, the surfactant flood must be modified to address these complications. The Office of Science and Technology's subsurface contaminants focus area is sponsoring research to address another complication of using surfactants to increase the solubility of dense nonaqueous phase liquids, or DNAPLs. Because surfactants reduce the capillary forces responsible for stabilizing DNAPL pools in the subsurface, these technologies may increase the mobility of DNAPLs and result in the spread of contamination into previously uncontaminated regions. SCFA research will provide guidance for site-specific system designs to minimize the risk of remobilizing DNAPLs. For a synopsis on the avenues SCFA is investigating, see pages 62-68 of the August 1996 Rainbow Book on the SCFA. Two other sources of information may be of interest to you. The first edition of an innovative technology practices manual for surfactants and co-solvents was released in April. Rice University, which has conducted extensive research on surfactants, prepared the manual under a grant from the Advanced Applied Technology Facility at the U.S. Department of Defense. To receive a manual, fax your request to Donald F. Lowe, Ph.D., Rice University at (713) 285-5948. Include your name, title, company or organization, mailing address, telephone number, fax number, and e-mail. Researchers at the University of Oklahoma studied the inefficiency of conventional pump-and-treat methods for removing DNAPLs and identified surfactants as a promising technology. Researchers also examined regulatory approval and economics, which are considered the primary obstacles to widespread implementation of surfactant-enhanced subsurface remediation. Results of their studies are described in the environmental research brief "Surfactant-Enhanced DNAPL Remediation: Surfactant Selection, Hydraulic Efficiency, and Economic Factors" (EPA/600/S-96/002). To order, call EPA's Robert S. Kerr Environmental Research Center at (405) 436-8651. |
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