Increased emphasis on the problems associated with leaking underground storage tanks and underground pollution in general has created a need for technology to reduce or eliminate the associated contamination. To date, package air stripping units seem to have received the broadest acceptance as the preferred approach for removing volatile organic compounds (VOC) from contaminated water. These units remove VOC from water by stripping them in an air stream as contaminated water falls down over a porous medium to increase surface area. The resulting contaminated air is either vented directly to the atmosphere or is passed through expensive activated carbon columns to remove contaminants.Environmental Technology Southeast, Inc. is developing a low cost biological active air filtration unit (BAF) to replace activated carbon in this application or to enhance the useful life of activated carbon through use as a treatment step prior to activated carbon. The filter is comprised of an organic medium which exhibits an adsorption affinity for VOC. The medium is seeded with commercially available microbes acclimated for selected VOC degradation. It is anticipated that the microbes will act to continually replenish active adsorption sites within the column. Properly designed columns could conceivably never need to be replenished and would have a very low maintenance cost.
