Sulfuric acid modified expanded vermiculite cover for reducing ammonia emissions from animal slurry storage

Animal slurry storage is an important source of NH₃ emission which has raised a high attention regarding its influence on air quality and environment health. There is an urgent need to develop an efficient, green and safe technology for reducing NH₃ emission. This study introduced a novel method of reducing NH₃ emission from dairy slurry storage using H₂SO₄ modified expanded vermiculite cover (H₂SO₄-VM1). Results showed that NH₃ mitigation of 87% was achieved in the treatment of H₂SO₄-VM1 during 77 days of slurry storage, which could be mainly caused by conversion of free NH₃ to NH₄⁺ in acidified slurry surface and vermiculite layer, the cover barrier for gases emissions, NH₄⁺ adsorption by vermiculite cover, and direct adsorption of free NH₃ in the vermiculite layer. The NH₃ mitigation of H₂SO₄-VM1 was comparable to that (90%) of the traditional method of H₂SO₄ acidification for slurry storage (H₂SO₄-AC1). The N₂O emission, H₂S emission, and H₂SO₄ consumption in H₂SO-VM1 were 28, 93 and 39% lower than those in H₂SO₄-AC1, respectively. Economic cost calculated based on material input in H₂SO-VM1 method was 0.40 USD m^-2 slurry. It's suggested that H₂SO₄-VM1 can be a possible alternative for reducing NH₃ emissions from animal slurry storage.