Emissions of NH3, H2S and CO2 from swine slurry as affected by surface liquid disturbance

Abstract

Livestock production can cause environmental problems; including global warming, land degradation, air and water pollution and loss of biodiversity cause in a source of a large number of different airborne contaminants which can have negative consequences for people, animals and environment. The most important gases related to animal production are: ammonia, carbon dioxine and hydrogen sulphide. Knowledge about gas release from the manure and behaviour in fron of disturbances is important to develop technologies to ensure farm safety and reduce emissions of pollutant compounds. In this thesis, behaviours of ammonia, carbon dioxide and hydrogen sulphide are studied when the slurry is disturbed under different airflow rates and different initial pH manure. How the pH was affected by slurry disturbances, changes on pH surface and how it was influenced by the airflow conditions was aldo investigated by measuring the pH at three different depths (0.5 to 1,4 and 6cm) and three different positions (at locations were the disturbance was created (average from the two holes), and in the middle of the slurry surface (were not active disturbance was created). The effect of acidification and the crust formation on the ammonia, carbon dioxide and hydrogen sulphide emissions was also studied. Two types of slurry were investigated to evaluate the effect of ageing. As in a farm the slurry surface can be frequently altered by the addition of new slurry (animal's excreta), cleaning water from the washing processes or slurry mixing during emptying the manure pit; an analysis of how the emission increased in these transient periods and the risks that this could suppose for the workers and the animals.