Development of a "Second Generation" Biofiltration System, 1999 Environmental Conference Proceedings

Gregory T. Kleinheinz,Gary D. McGinnis, Brett A. Niemi & Jason T. Hose

Michigan Technological University

Biofiltration utilizes microbial processes which are immobilized on a solid support to biodegrade contaminants in air. Biofilters traditionally have been utilized in applications where there is a high volume of air containing low levels of compounds. There are several operational problems biofilters are currently encountering. Some of these problems include systems which are very large, microbial breakdown of the solid support, cycling of compounds onto the biofilters (uneven amounts of compounds in the air), and very short residence times in the biofiltration units. This project was undertaken to determine the feasibility of using physical/chemical methods to adsorb and then desorb analytes in order to convert a dilute, high volume, air stream to a more concentrated low volume air stream. The chemical/physical (adsorption/desorption) system will also serve to provide a relatively constant air stream to the biofilters in order to alleviate the perturbations to the system as a result of uneven analyte concentrations. The ability to concentrate a dilute air stream and provide a constant stream of VOCs to the biofiltration unit will allow for smaller, more efficient, and more economical biofilters. Two years of laboratory studies on these coupled systems has shown that they are indeed able to efficiently concentrate dilute streams, and the coupled biofilters are able to remove 90%+ of the VOCs from the adsorption/desorption unit. The final year of the project will be a pilot-scale demonstration of the technology at an industrial site.