#04-039

Complete

Date Full Report Received

07/31/2005

Date Abstract Report Received

12/20/2006

Investigation

Institution:
Primary Investigator:

A vertical biofilter may be a good option for reducing odor and gas emission when not enough space is available to install a horizontal biofilter. The vertical biofilter is cylindrical with the walls containing the media and the cylinder center biofilter inlet connected to the barn exhaust fan. The inner wall of the biofilter media is tapered (i.e. thicker at the top and narrower at the bottom), thereby compensating for media settling. This design achieves a more uniform airflow across the media surface. A 9.6 degree taper provided the most uniform airflow after biofilter media settling for two filter thicknesses of 12 and 24 inches that were tested.
The recommended wetting technique to keep the media at proper moisture is to lay a soaker hose on top of the vertical biofilter and let the water seep down through the media. Soaker hoses suspended vertically did not provide for uniform media moisture through the system.
A vertical biofilter will continue to reduce odor and hydrogen sulfide emissions during cold weather (-20º F) provided the air entering the biofilter is warm (50º F).