Objective:
The objective of this project is to demonstrate the efficacy of a fluidized bed bioreactor (FBR) system for the treatment of low concentrations of perchlorate in groundwater. Biological treatment is considered one of the most promising technologies for the remediation of perchlorate-contaminated water. For this demonstration, a critical issue in applying such a biological treatment technology is qualifying the system's robustness in operating effectively under various loading conditions. The project will focus on how low perchlorate concentrations, self-seeding of the reactor, and short-term interruptions in system operation affect performance. Such effects have not been evaluated with any of the other FBR systems currently in operation. This study also will evaluate operation of the FBR treatment system in conjunction with additional downstream equipment that will result in production of potable water. Such a remediation system will provide a low-cost alternative for the treatment of perchlorate-contaminated drinking water aquifers. Technology Description: A fluidized bed bioreactor is a fixed-film reactor in which the biological media is suspended or fluidized within the reactor vessel by the upward flow of water through the system. Typically, sand or granular activated carbon is used in these systems for microbial growth attachment. Because the media particles are small and suspended, they present a large surface area for microbial growth and promote a biomass density that is often several times that of other bioreactor designs under similar loading conditions. An electron donor (i.e., acetic acid) is provided to the FBR where, under anoxic conditions, it is used in the denitrification/perchlorate-reduction process. The byproducts of the process are nitrogen gas, chloride ions, carbon dioxide, heat generation, and additional biomass. The effluent water from the FBR then passes through an aerator, multimedia filter, and liquid granular activated carbon, resulting in the production of potable water. Expected Benefits: Typically, for drinking water applications, existing perchlorate removal technologies utilize the principle of simple phase transfer of the contaminant from the water to the solid phase. This requires additional treatment of perchlorate in the solid phase. In contrast, the FBR technology completely destroys the nitrate and perchlorate in the influent water. The complete destruction of the nitrate and perchlorate ions ensures that they will no longer be environmental hazards for future generations. In addition, costs for the FBR treatment train have been shown to be up to 60% less expensive than current state-of-the-art treatment technologies. It is expected that this demonstration will corroborate such findings regarding the economic benefits of this technology to the Department of Defense. (Anticipated Project Completion - 2007) Principal Investigator: Dr. Todd Webster Shaw Environmental, Inc. 1230 Columbia Street, Suite 1200 San Diego, CA 92101 Telephone: (619) 446-4529 Fax: (619) 239-1238 E-mail: todd.webster@shawgrp.com DoD Liaison: Ms. Barbara Sugiyama Naval Facilities Engineering Service Center 1100 23rd Avenue, ESC 411 Port Hueneme, CA 93043 Telephone: (805) 982-1668 Fax: (805) 982-4304 E-mail: barbara.sugiyama@navy.mil | 
