Objective: Perchlorate in drinking water aquifers is a common problem in areas where perchlorate is manufactured or used in industrial processes. Perchlorate is highly soluble and mobile in the subsurface environment, and conventional water treatment technologies such as air stripping and chemical oxidation have proven relatively ineffective for in-situ perchlorate removal or destruction. Perchlorate is biodegradable under anaerobic conditions, and enhanced anaerobic bioremediation using organic substrates may be an effective method for degrading perchlorate in situ. The objective of this project is to evaluate the efficiency and design criteria of a permeable mulch biowall for anaerobic degradation of perchlorate in shallow groundwater. Technology Description: A permeable mulch biowall will be constructed across the flow-path of a groundwater plume contaminated with perchlorate. This treatment method relies on the flow of groundwater under a natural hydraulic gradient through the biowall to promote contact with soluble organic matter. Under these conditions, microbial degradation of organic carbon within the biowall produces conditions that support the anaerobic degradation of perchlorate and chlorinated degradation products (i.e., chlorate and chlorite). The biowall will contain a mixture of locally derived, actively-composting shredded plant material as a mulch carbon source as well as coarse sand to prevent compaction and maintain permeability. Continuous trenching methods are currently capable of rapidly installing biowall trenches to depths of 25 to 35 feet in unconsolidated sediments. Expected Benefits: Permeable mulch biowalls can be readily installed using conventional construction techniques. Biowall materials such as tree mulch, compost, and sand can be obtained at relatively low cost. Biowall systems are anticipated to operate effectively over periods of 5 to 10 years or more with no operations and maintenance (O&M) costs other than periodic performance monitoring. As such, they offer a substantial cost savings when compared to other enhanced bioremediation systems that require periodic injection of substrates and maintenance of injection systems. Demonstration of this technology has the potential to save the Department of Defense millions of dollars in remediation costs for perchlorate plumes. (Anticipated Project Completion - 2008)
Principal Investigator:
Dr. Ross Miller
Parsons Infrastructure & Technology Group, Inc.
406 W. South Jordan Parkway, Suite 300
South Jordan, UT 84095
Telephone: ((801) 572-5999
Fax: (801) 572-9069
E-mail: ross.miller@parsons.com DoD Liaison:
Ms. Erica S.K. Becvar
HQ AFCEE/TDE
3300 Sidney Brooks, Building 532
Brooks City-Base, TX 78235-5112
Telephone: (210) 536-4314
Fax: (210) 536-5989
E-mail: erica.becvar@brooks.af.mil | 
