Epsilon Archive for Student Projects

Abstract

Methane (CH4) is the most common greenhouse gas being emitted from Sweden’s agriculture, where approximately 4.5% of Sweden’s total emission in 2022 originated from livestock manure storage facilities, highlighting the importance of optimizing manure degradation processes. This study was part of a project led by Research Institutes of Sweden, which aimed to investigate if CH4 emissions could be reduced by adding ammonium sulphate ((NH4)2SO4) to organic fertilizers. The quantitative study was conducted under mesophilic conditions (37°C) for 29 days, focusing on the effects added (NH4)2SO4 had on samples of two types of digestates and one type of cattle manure. In addition to CH4 emission, hydrogen sulphide (H2S) emissions – known for its toxicity at low concentrations - were measured. The study also examined changes in volatile solids (VS), pH levels, and volatile fatty acid (VFA) composition before and after the experiment.

The results were conclusive, CH4 emissions were reduced when (NH4)2SO4 was added to the respective fertilizer. However, H2S emission increased significantly in all samples containing (NH4)2SO4. This suggests that adding (NH4)2SO4 to organic fertilizers could potentially be a way of reducing CH4 emission during the storage of digestates or animal manures. However, further research is needed to determine its applicability under farm conditions. Additionally, it is crucial to assess the risks posed by H2S exposure to workers handling such materials under realistic working conditions.