Inhibition of methane production in cattle slurry using an oxygen-based amendment

Abstract

Cattle slurry storage is a major point source for methane (CH4) and ammonia (NH3) emissions globally. Efficacy of an oxygen-based amendment in reducing these emissions was investigated. Two 1.6 kg cattle slurry incubations, each lasting for 40-days, were carried out in a climate-controlled chamber with CH4 and NH3 emissions measured. Multiple peroxide sources acting as a source of oxygen were tested to examine how compatible they were for addition to cattle slurry. An amendment comprising of hydrogen peroxide (HP) and potassium iodide (KI) has been highlighted as method to reduce CH4 emissions from this source. While urea hydrogen peroxide and sodium percarbonate reduced CH4 emissions, they increased the slurry pH and subsequently NH3 emissions by 209 and 42%, respectively. Hydrogen peroxide did not infer any pH increase upon the slurry and therefore no increase in NH3 emissions was observed. Hydrogen peroxide and KI were able to reduce CH4 emissions by 63% during slurry storage. The use of this treatment on a larger scale system should be considered in the future considering the large reductions achieved.