Biofilters, bioreactors used for pollution control, can effectively treat a variety of odorous and hazardous emissions, but uncertain medium longevities and associated costs limit biofilter adoption. To improve medium-life estimations for biofilter end-users, litter bags were used to compare decay rates of common biofilter medium types and test the effects of nitrogen (N) enrichment and livestock production emissions on medium decay in a full-scale biofilter over a 27-month period. Generally, “by-product” media (mulch, corn cobs) decayed faster than hardwood media, with decay of softwood media the slowest. Analysis showed nutrient content was the best predictor of early-stage decay, while carbon fractions and nutrient content best predicted medium longevity. N amendments and N-rich barn emissions were found to hasten medium decay. By identifying decay rates and rate predictors specific for biofilter media, we provide biofilter engineers and farmers with a quantitative way to improve medium selection based on the trade-offs between medium cost and replacement frequency.
Bibliographical noteFunding Information:
A special thanks to our collaborators, Dr. Kevin Janni, Dr. Larry Jacobson, and Brian Hetchler, for their biofilter expertise and to Dr. Justin Kaffenberger for his thoughtful discussion. These studies were supported by grants from the United States Department of Agriculture, National Institute of Food and Agriculture, Agriculture and Food Research Initiative (USDA/2010-85112-20520 and USDA/2012-69002-19880), and the USDA NIFA McIntire-Stennis Project #MIN-12-074 at the University of Minnesota.
© 2015, Springer-Verlag Berlin Heidelberg.
- Decay rate
- Litter bag