| Biofilter technology is a growing technology for air pollution control. Gases that need treatment are passed through a bed of organic solids, such as compost, causing pollutants to adsorb onto organic matter where a microbial population degrades or stabilizes these compounds through various metabolic pathways. Biofiltration is an inexpensive method for treating waste gases since materials are easy to come by and maintenance is simple. Because biofilter costs are so low, certain industrial facilities that have low overhead, such as an agricultural livestock operations, are considering biofiltration as an option for treating undesired odors.; Biofilter performance depends mainly on the microbial population, viability, and ability to degrade incoming pollutants within the solid matrix. Ammonia (NH3) gas was found to suppress microbial activity with high concentrations, yet also represents the main source of nitrogen, a key element for microbial growth.; Laboratory-scale yard-waste compost biofilters were used as an adsorption medium and microbial support for these studies. First, certain compost characteristics such as pH titration, particle sizing, bulk and particle density, and moisture content equilibrium were characterized. Secondly, NH3 gas adsorption equilibrium as a function of temperature, moisture content, pH and NH 3 gas concentration, and mass transfer rates were studied and certain equilibrium relationships were identified. Third, compost was given a bacterial inoculation and fed an NH3 gas stream to evaluate constants for a Michaelis-Menten reaction rate kinetic model. Finally, equilibrium and kinetic equations were combined to predict changes within a biofilter based on incoming NH3 and form a strategy for biofilter design using these modeling equations. |
