Ten different polystyrene foam materials of thickness ranging from 1 to 3 cm were tested for their ability to reduce ammonia and odors emissions from the surface of stored liquid swine manure. The manure was stored in 0.30 m diameter and 0.365 m high pails. Ammonia concentrations were measured and odor emission was evaluated using cotton fabric swatches. All the materials evaluated reduced ammonia emissions from 45 to 90% compared to uncovered manure. Odor panelist could identify an odor intensity reduction as result to cover use. The more effective cover materials presented a sufficient gas permeability allowing the gases to pass through the foam an undergo aerobic breakdown. for less permeable covers, the gas (odor and ammonia) passed around the covers.

The cover testing was done on a very small scale which rises questions about the validity of such results on a larger scale. The odor analysis done with the cloth swatch technique can also be questioned if we consider the results obtained by R.E. Nicolai et al., 1997 (in the same conference).