The sand biofilters exhibited removals of 90% and greater with a long term loading of 6-8 inches/week and 1000 ppm AFFF (V/V). Sand was found to be a satisfactory biofilter media. The soil biofilters plugged under the same conditions; for this reason soil was found to be unsatisfactory as a biofilter media. Removals were 90% and above.

The applicability of the Beckman Microtox Toxicity Monitor was determined for measuring AFFF toxicity. The Microtox measures light reduction of a luminescent bacteria. The Microtox system exhibited a minimum sensitivity of 4 ppm AFFF and demonstrated an accuracy of (+OR-) 1 to 2% light. The Microtox was 3 and 4 times as sensitive to AFFF toxicity as fish and invertebrate tests. The Microtox was found to have comparable toxic response frequency and sensitivity to fish and invertebrate tests for 100 industrial effluents (EPA data) indicating broad case applications.

The biofilter unit process, a biological filtering system using sand, soil, or activated carbon as a filter media, is being developed as a cost effective secondary or tertiary level treatment option for small DOD fire fighting facilities.

The carbon biofilter system was found to be a cost effective, long life adsorption-biodegradation filtering unit with tolerance for high (16,000 ppm AFFF V/V) and fluxuating loadings. Bioregeneration of the carbon was indicated.

A method for the direct quantitation of AFFF using High Performance Liquid Chromatography (HPLC) was developed. The method is sensitive to 2 ppm AFFF without sample concentration and is the only direct measure of AFFF available.

This research effort was initiated to determine the effectiveness of a biofilter for the treatment of Aqueous Film Forming Foam (AFFF) waste waters generated at Department of Defense (DOD) fire fighting training facilities. AFFF waste waters have a high oxygen demand and are toxic to aquatic life.