科研之友
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摘要
Acidification of slurry is a treatment known to reduce ammonia emissions and it is currently applied at the farm scale in Denmark by adding concentrated sulfuric acid (H2SO4). However, several risks are associated with the use of this strong acid and therefore an alternative is required to protect the health of farmers and animals. The effects of five different additives at two target pH values, 5.5 and 3.5, on the composition of two different slurries (pig and dairy) were assessed. The evolution of pH and NH3 volatilization from acidified and non-acidified slurries, kept in closed vessels at an ambient temperature of 15 degrees C, was followed during a storage period of 60 days. Acidification to pH 5.5 with all additives significantly reduced NH3 emissions, and the greatest decreases relative to raw slurry were obtained with H2SO4 (75% in pig and 81% in dairy slurry) and alum (69% in pig and 87% in dairy slurry). Acidification to pH 3.5 reduced NH3 emissions in both slurries to values considered negligible during the whole storage period. However, longer storage periods should be studied to evaluate NH3 evolution and slurry composition in the longer-term. Sulfuric acid and alum were the additives which could be used in the lowest amounts to decrease the pH to 5.5 and were the most efficient in reducing NH3 emissions. Acidification promoted P solubilization, except when alum was used. Nevertheless, this initial solubilization of P when the pH was decreased to 5.5 had been reversed after two weeks of storage. In conclusion, alum can be considered as a good alternative to H2SO4 when the pH is lowered to 5.5, as the amount of this additive used was similar to that of H2SO4 and it was as efficient as H2SO4 with respect to reducing NH3 volatilization during storage.
- 出版日期2016-9-10
