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

Abstract

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.