Use of Ultrasound to Improve the Effectiveness of Permeable Treatment Walls
During the early history of the space program, areas of Launch Complex 34 (LC-34) were polluted with chlorinated solvents used to clean Apollo rocket parts. These solvents were classified as dense non-aqueous phase liquids (DNAPLs). Left untreated in the ground, DNAPLs are able to contaminate fresh water sources. Remediation methods that have been used in the past (e.g., pump and treat) have had limited success and are very expensive to implement.

The use of a permeable reaction barrier (PRB) using zero-valent metals to clean-up contaminated groundwater is an extremely economical remediation tool. It is passive in nature and allows for long-term cleanup with little above ground intervention. However, if the PRB cannot maintain its reactivity, then the economic advantages of the new technology diminish quickly. Kennedy Space Center has developed a technology that introduces ultrasound into a PRB for the purpose of regenerating zero-valent metals. The ultrasound wave is introduced using a submersible transducer in a groundwater sampling well. The system is hooked-up to a self-propelled system that slowly lowers the ultrasound transducer into the groundwater where the PRB is located. Ultrasound waves are allowed to contact the zero-valent metal particles for a set period of time over the full length of the PRB. This "cleaning" method removes by either acoustical cavitation or acoustical streaming any corrosive or precipitate buildup that is occluding the zero-valent metal surface. This allows for quicker and more efficient degradation of the halogenated contaminant on the metal's surface.

EnviroMetal Technologies Inc. (ETI), a world leader in applications of PRB technology for the remediation of contaminated groundwater, has licensed the ultrasound technology from NASA. With experience at over 80 sites in North America, United Kingdom, Europe, Japan and Australia, ETI provides a range of advisory and support services to site owners, remediation consultants and contractors to assist them with the design and installation of their PRB systems and other passive remediation technologies.

NASA Involvement

Social/Economic Benefit

Industry Partner
EnviroMetal Technologies, Inc.

NASA Partner
Kennedy Space Center

Point of Contact John Vogan, President
EnviroMetal Technologies, Inc.
Suite 7, 745 Bridge St. W.
Waterloo, Ontario N2V 2G6
Phone: (519) 746-2204
Fax: (519) 746-2209