Odour emission rates from manure treatment/storage systems

The effects of agitation, liquid-only manure, depth and time on odour emiss ion rates were investigated. Manure storage tanks were filled to incrementa l depths every two weeks. At each depth odour samples were collected twice. The second sample was collected seven days after the first. Odour concentr ation was measured with an olfactometer. Three different pig-manure treatme nts were investigated. In one treatment, slurry manure in a storage tank wa s agitated before and during odour sampling. In a second treatment, the set tlable solids in manure were removed gravimetrically over 24 hours and liqu id manure was pumped to a storage tank. In the third treatment (control), o dour samples were collected from unseparated and undisturbed slurry manure. Overall, the odour emission rates in the agitated manure treatment ranged between 0.39 and 1.02 ou s(-1) m(-2), increased with depth and decreased wi th time, i.e. after seven days at each depth. In the liquid-only manure tre atment, the emission rates ranged between 0.09 and 0.69 ou s(-1) m(-2), inc reased with depth but the effect of time was not evident. In the control tr eatment, the emission rates ranged between 0.20 and 0.66 ou s(-1) m(-2) and increased with depth on the first occur sampling day but decreased with de pth on the second sampling day.