Hydrogen sulfide emissions from cattle manure: experimental study

Animal waste products, manure, in particular, are the sources of gases harmful tohuman and animal health. Hydrogen sulfide (H2S), which is produced from the breakdown oforganic matter in animal faeces, is one of them. Its concentration in the cow barn air should notexceed 5 mg m−3. A special laboratory setup was designed and the level of hydrogen sulfideemissions from the cow manure was determined depending on the time and manure temperatureand moisture content. The most intensive emission of hydrogen sulfide from manure was in thefirst 24 hours – the increment of H2S concentration was 0.168 mg m−3 per hour average. Duringthe next 24 hours, it was 0.021 mg m−3 per hour. When the manure temperature increased, H2Sconcentration increased also; when the temperature manure decreased, H2S concentrationdecreased also. In 48 hours, the hydrogen sulfide concentration was 1.1 mg m−3 at the manuretemperature of +3.0 °C. At the manure temperature of +23.4 °C and 21.3 °C, H2S concentrationwas 6.53 mg m−3and 4.97 mg m−3, respectively. The higher was the manure moisture content,the lower was the emission of hydrogen sulfide into the environment. After 24 hours under themanure moisture content of 88.5% and 92.5% and its temperature of 21 °С ± 0.3 °С, thedifference in the hydrogen sulfide concentration was 1.18 times depending on the manuremoisture content. The selected regression equations described the dependence of the hydrogensulfide concentration on the considered factors. The determination coefficients and Student'scriteria proved the reliability of the results obtained at the significance level P ≤ 0.05.