Evaluation of Simplified Covering Systems to Reduce Gaseous Emissions From Livestock Manure Storage

Ammonia, methane, and carbon dioxide are the primary atmospheric emissions from cattle and pig farms. Asignificant part of these emissions is produced by the decomposition of slurry organic matter during manure storage andtreatment phases. Present solutions to contain emissions from storage lagoons generally involve reducing the free surface ofthe slurry by covering it either with permanent fixed structures or temporary floating ones. This study investigated theeffectiveness of five simple floating covers in reducing emissions from pig and cattle slurry. The coverings included vegetableoil (a mixture of rapeseed and soybean oil), expanded clay, chopped maize stalks, chopped wheat straw, and chopped woodchips. All were tested at two different thicknesses: 70 and 140 mm for solid coverings, and 3 and 9 mm for liquid. Slurrysamples covered with the above-mentioned materials were placed in nine stainless steel airtight cylinders measuring 190 dm3.Gaseous and odor concentrations in the headspace were monitored using a Bruel & Kjaer 1302 multi-gas monitor and a T07olfactometer. The flotation aptitude of the different coverings was also tested. Results revealed substantial differences inammonia emission reduction efficiency (1% to 100%) and odor abatement (0% to 90%), and high levels of reduction efficiencywere achieved by all the tested covers at the higher thickness. However, equally valid results were not obtained for methaneemissions reduction. In regard to flotation aptitude and cover deterioration on slurry, expanded clay and wood chipsdemonstrated long-term resistance to both deterioration and sinking.