The behavior of particulate matter in bioreactors for air pollution control
Bioreactors for air pollution control have been proposed for a range of unconventional and novel applications. Probably one of the largest potential applications is the treatment of combustion gases from stationary sources. Several studies have addressed treatment of NOx and SOx. To date, these developments have essentially remained laboratory studies, and demonstration and full-scale implementation have yet to occur. The control of PM in three laboratory-scale bioreactors was investigated. The results showed great differences in particle removal among the three bioreactors. The biofilter exhibited essentially 100% removal at air contact times ranging from 20 to 81 sec. On the other hand, PM removal in the biotrickling filter was strongly affected by gas residence time and the size of the PM being treated. The reactor packed with polyurethane foam showed better performance than that packed with Pall-rings, with removal efficiencies ranging from 35 to 95% for the foam biotrickling filter and removal from 0 to 75% for the biotrickling filter packed with Pall rings, at gas residence time ranging from 23 to 93 sec. An existing model for particle filtration through granular beds proved to be adequate to fit most experiments. The differences of removal capacities among these reactors were attributed to the difference in the equivalent diameter of the packing. Thus, biofilter and biotrickling filters could be utilized for particulate matter control, but careful engineering is required so that particle treatment objectives are met. This is an abstract of a paper presented at the AWMA 97th Annual Conference and Exhibition (Indianapolis, IN 6/22-25/2004).
