Emission of odorous and gaseous compounds such as hydrogen sulphide (H2S) from livestock facilities can be a major impediment to its daily operations and potential expansion. Occupational and environmental concerns require the control of H2S emissions. A treatment approach used in the oil industry in which nitrite and/or molybdate are used as metabolic inhibitors to control the production of H2S in oil reservoirs was shown to be effective in controlling H2S emissions from swine manure.<p> The addition of nitrite and molybdate to swine manure was investigated in closed laboratory scale systems and then evaluated in semi-pilot scale open systems and in specifically designed chambers aiming to simulate an actual swine barn. The effect of manure age (extent of storage) on H2S emissions and the levels of nitrite and molybdate required for effective control of these emissions were assessed. Laboratory scale tests showed that emission of H2S was dependent on manure age. Fresh manure emitted the highest level of H2S and the level of emission decreased as manure age (1-6 months) increased. With fresh 1, 3, and 6-month old manures average H2S concentration in the headspace gas of the closed systems were 4856b460, 3431b208, 1037b98 ppm, and non-detectable (<0.4 ppm), respectively. This translated to lower levels of nitrite or molybdate required to control H2S emission with increase in manure age. When compared to molybdate, the addition of nitrite initially led to lower levels of H2S but its effect was only temporary and not as persistent as molybdate. In the semi-pilot and room scale tests H2S levels emitted from untreated fresh manure (831¡Ó26 ppm and 88.4 ppm, respectively), were significantly lower than those observed in the laboratory system (4856¡Ó460 ppm). Moreover, the levels of molybdate required to control the emission of H2S were much lower in both the semi-pilot system and in the room scale chamber than in the closed system (0.1-0.25 mM as opposed to 2 mM).<p> Small scale land application of manure treated with 0.1 mM molybdate did not raise the level of molybdenum in the soil that could cause potential toxicity to plants and animals. No major differences in the nutrient properties of the soils exposed to the treated and untreated manure were observed. Finally, a preliminary feasibility study of this treatment approach showed that the cost associated with this control approach was less than 1% of the total production cost.

Emission of odorous and gaseous compounds such as hydrogen sulphide (H2S) from livestock facilities can be a major impediment to its daily operations and potential expansion. Occupational and environmental concerns require the control of H2S emissions. A treatment approach used in the oil industry in which nitrite and/or molybdate are used as metabolic inhibitors to control the production of H2S in oil reservoirs was shown to be effective in controlling H2S emissions from swine manure.<p> The addition of nitrite and molybdate to swine manure was investigated in closed laboratory scale systems and then evaluated in semi-pilot scale open systems and in specifically designed chambers aiming to simulate an actual swine barn. The effect of manure age (extent of storage) on H2S emissions and the levels of nitrite and molybdate required for effective control of these emissions were assessed. Laboratory scale tests showed that emission of H2S was dependent on manure age. Fresh manure emitted the highest level of H2S and the level of emission decreased as manure age (1-6 months) increased. With fresh 1, 3, and 6-month old manures average H2S concentration in the headspace gas of the closed systems were 4856b460, 3431b208, 1037b98 ppm, and non-detectable (<0.4 ppm), respectively. This translated to lower levels of nitrite or molybdate required to control H2S emission with increase in manure age. When compared to molybdate, the addition of nitrite initially led to lower levels of H2S but its effect was only temporary and not as persistent as molybdate. In the semi-pilot and room scale tests H2S levels emitted from untreated fresh manure (831¡Ó26 ppm and 88.4 ppm, respectively), were significantly lower than those observed in the laboratory system (4856¡Ó460 ppm). Moreover, the levels of molybdate required to control the emission of H2S were much lower in both the semi-pilot system and in the room scale chamber than in the closed system (0.1-0.25 mM as opposed to 2 mM).<p> Small scale land application of manure treated with 0.1 mM molybdate did not raise the level of molybdenum in the soil that could cause potential toxicity to plants and animals. No major differences in the nutrient properties of the soils exposed to the treated and untreated manure were observed. Finally, a preliminary feasibility study of this treatment approach showed that the cost associated with this control approach was less than 1% of the total production cost.