Objective: The objective of this project is to evaluate the efficacy of using fixed-bed (FXB) biological reactors (bioreactors) to remove perchlorate from drinking water. Specific objectives include demonstration of sustained removal capabilities, identification and evaluation of process limitations and potential failure scenarios, and development of realistic designs and cost estimates for full-scale drinking water FXB biological perchlorate treatment. Technology Description: Fixed-bed biological processes utilize a stationary bed of media such as sand, plastic, or granular activated carbon on which perchlorate-reducing biofilms develop. Water is drawn from a well, amended with an electron donor such as acetic acid, then pumped across the media bed. The necessary perchlorate-reducing biological activity is achieved by keeping the media in contact with the water for approximately 1 month (i.e., no perchlorate-reducing inoculum is required). While FXB bioreactors have been applied as a perchlorate treatment process for several years, no system has been tested at flow rates above approximately 2 gallons per minute (gpm). As a result, scalability is not well understood. This project will test a FXB bioreactor at flow rates up to 24 gpm. More realistic design and operating parameters will be developed for use in facility layouts and more credible cost estimates. Additionally, process robustness and post-treatment requirements will be more fully characterized. The project team also will use mathematical models to help understand and optimize overall perchlorate removal performance across the FXB bioreactors. Both steady-state and dynamic models will be used so that a broad range of operating and loading conditions can be simulated. Refinement of the models throughout this project will improve the ability to extrapolate demonstration-scale performance to site-specific full-scale applications. Expected Benefits: The major performance strengths of a FXB biological perchlorate-reducing process are as follows: (1) perchlorate is converted to innocuous chloride and oxygen rather than concentrated; (2) multiple contaminants can be removed in a single reactor (e.g., perchlorate, nitrate, bromate, other oxidants, disinfection by-product precursors, chlorinated solvents); and (3) design and operation of FXB bioreactors are comparable to the design and operation of conventional granular media filters. Estimates indicate that capital costs for applicable FXB bioreactors are substantially lower than capital costs of membrane-based perchlorate removal processes and comparable to those associated with ion exchange-based perchlorate removal processes. The real cost benefit of FXB biological perchlorate treatment relates to the extremely low operations and maintenance (O&M) costs, which are estimated to be a small fraction of all abiotic perchlorate treatment processes. (Anticipated Project Completion - 2007) Principal Investigator: Dr. Jess Brown Carollo Engineers, P.C. 401 North Cattleman Road, Suite 306 Sarasota, FL 34232 Telephone: (941) 371-9832 Fax: (941) 371-9873 E-mail: jbrown@carollo.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 | 
