Effect of anaerobic digestion on odor and ammonia emission from land-applied cattle manure

High ammonia (NH₃) and odor emission can occur after land application of liquid animal manure. This study was aimed at evaluating NH₃ loss and odor nuisance after field application of cattle manure and how it is affected by two anaerobic digestion strategies: i) digestion of cattle manure alone and ii) digestion with catch crops and dilution by water. A system of dynamic chambers with online measurements of NH₃ and odorous compounds (summarized as odor activity value, OAV) was used. Two experiments were conducted under different temperature conditions. The results demonstrated that anaerobic digestion did not affect NH₃ loss but did decrease OAV. Addition of catch crops and water to the digestion process reduced both NH₃ loss and OAV. Cool temperature in one of the experiments had a large effect on both NH₃ and odor emissions, and at high temperature the differences between treatments increased.