Swine manure storage covers for odor control

Twenty-one, 750-L (200 gal) polyethylene tanks were filled with swine manur e. Air samples were collected 24 and 48 h after each manure addition. The s amples were tested for odor strength using a dynamic olfactometer and for h ydrogen sulfide concentration using a Jerome(R) meter. The experimental des ign consisted of a randomized block design containing three blocks (replica tions) of seven treatments. The seven treatments included no cover (control ), straw mat, vegetable oil mat, straw/oil mat clay ball mat, PVC/rubber me mbrane, and geotextile membrane. Statistical analysis indicated that all th ree main effects--cover treatment, collection period and time after manure addition-significantly (5% level) affected odor units and hydrogen sulfide concentration. Considering all air collections, the six covers reduced odor units and hydrogen sulfide concentration at various points in the study: b ut not in a consistent manner The straw mat and PVC/rubber membrane signifi cantly reduced both odors units and hydrogen sulfide concentration consiste ntly 24 h after manure addition during the first three collection periods. Mixing vegetable oil with straw appears to increase longevity, of the cover as compared to straw only. The vegetable oil layer when mixed with the man ure, produced a distinctively offensive non-swine odor. The clay ball mat r educed emissions, although,oh not as well as other covers. A geotextile mem brane may be a possible cover choice, since the fabric is self-floating and the biofilm that grew on the mat could self-seal the cover. A straw mat (p ossibly including vegetable oil) and PVC/rubber membrane appear to be the m ost effective covers in reducing both odors and hydrogen sulfide. Oil alone should not be used as a cover.