Biofilter Process for Treatment of Combined Paint Stripping (Methylene Chloride) and Spray Paint Solvents

This Phase I SBIR effort involves the development and feasibility testing of an open-bed biofilter process for the simultaneous destruction of stripping solvents (methylene chloride) and paint solvents (toluene, xylene, methyl ethyl ketone, and n-butyl acetate) in air exhausts. Biofiltration is a process that utilizes microorganisms attached to an organic packing material such as compost to degrade hazardous pollutants in air. The objectives of the research are to: (1) determine if bacteria that degrade paint emissions can co-exist in a biofilter with bacteria that degrade methylene chloride such that sustained simultaneous degradation of methylene chloride and paint emissions can be accomplished; (2) develop a method to adequately control biofilter bed pH during treatment of methylene chloride vapors; and (3) determine biofilter performance at both high and low influent contaminant concentrations. The high concentration for each contaminant will be the 8-hour OSHA exposure limit for that particular target. At each influent concentration, biofilter performance will be evaluated at two different vapor contact times. The pH of biofilter packing is usually controlled by the addition of calcium carbonate to the packing material. During this Phase I effort, an alternative biofilter pH control mechanism will be tested.