SBIR-STTR Award

Methyl bromide is an effective fumigant that has been in use since the 1930s. However, the U.S. Environmental Protection Agency will soon prohibit the production and importation of methyl bromide because it has been found to be a significant ozone depleting substance. Although a number of significant research efforts have been conducted to find alternatives for soil and post-harvest fumigation, so far these alternatives are either more costly or not as effective as methyl bromide. Another possible approach to mitigate the ozone depleting effects of methyl bromide would be to capture and to recycle or to treat the methyl bromide to minimize its release into the atmosphere. Recent advances in biological waste air treatment and in biodegradation of methyl bromide suggest that biological treatment of methyl bromide vapors in a biotrickling filter may be a cost effective solution. The purpose of the proposed investigation is to determine the feasibility and efficacy of biotrickling filtration to treat offgases from agricultural operations that contain methyl bromide. The primary objective of the first phase will be to demonstrate methyl bromide treatment, and to determine treatment performance under various, yet controlled, operating conditions and to define important design information needed for full-scale systems. ANTICIPATED RESULTS & POTENTIAL COMMERCIAL APPLICATIONS OF RESEARCH The short term cost of phasing-out methyl bromide is estimated to exceed $300 million whereas the long term cost is in the billion of dollars. If successful, the proposed treatment of methyl bromide could demonstrate a strong case for exempting methyl bromide from regulation in applications where capture and treatment can be implemented. The proposed technology is easily applicable for post-harvest fumigation where waste air exits a fumigation building at a centralized location. A trailer mounted biotrickling filter would enable treatment at various sites. For pre-plant fumigation, biotrickling filtration will require an efficient methyl bromide capture mechanism. At least one is available for licensing from the University of California of Technology Transfer. Biotrickling filtration is cheap and environmentally benign and very well perceived by the general public.

The overall objective of Phase II is to further develop and optimize biotrickling filtration of methyl bromide and to demonstrate the technology in the field. At the end of Phase II, the Energy Resource Institute should be in the unique position of being able to commercialize biotrickling filter systems for the safe and reliable treatment of methyl bromide air streams from fumigations. Supporting objectives to be achieved during Phase II are to: 1. Complete the characterization of the pure, methyl bromide degrading microorganisms obtained in Phase I and select the best strains to be used in biotrickling filters. 2. Design, construct and test a new load-dampening system (laboratory-scale). 3. Design and construct a mobile pilot-scale biotrickling filter (including the load dampening system) for field demonstrations of effective methyl bromide treatment. 4. Demonstrate sustained and effective methyl bromide treatment at least at one quarantine fumigation facility, and at least one field fumigation. For the latter, this will include demonstration of a new collection system (two-layer tarp) to improve capture of methyl bromide from soil fumigations. 5. Develop a mathematical model of the load dampening-biotrickling filtration system to be used for system scale-up, system sizing, and for cost evaluation. 6. Fully evaluate the costs of the proposed technique, apply for patents and develop market opportunities.