Testing was done at North Carolina State Univ. on 3 pilot-scale biofilters and the apparatus related to the operation of such biofilters built to treat odorous air coming from the swine gestation building pit. The biofilter medium was a 3:1 mix of yard waste compost misture and wood chips misture. Temperatures, flow rates, and pressure drop were measured by a computer through out the testing and the computer also measured and controlled the moisture content of the biofilter medium. This project wanted to evaluate the performance of those biofilters and ensure that this setting would be useful for futur research projects on scientifc experiments of swine odor reductions. The odor measurements were done using the cotton swatch absorption method and the samples were analyzed by a panel. Odor intensity, irritation intensity and unpleasantness were the parameters measured in five tests and the reductions from the use of biofilters compared to untreated odorous air were 61%, 58%, and 84% respectively.

This pilot scale experiment is interesting because it could lead to larger scale installations. However the odor analysis done with the cloth swatch technique can be questioned if we consider the results obtained by R.E. Nicolai et al., 1997 (in the same conference).