EFFECTS OF ANAEROBIC DIGESTION AND SEPARATION OF PIG SLURRY ON ODOR EMISSION

Abstract

Storage and land application of livestock manure causes considerable odor nuisance to the surroundingneighborhood. Anaerobic digestion and separation of slurry change composition and physical properties of slurry and maytherefore lessen the odor pollution during storage and land application. An experiment was set up to study the effects ofanaerobic digestion and separation of slurry on the emission of odor. Odor concentration above treated and untreated slurrywas compared during storage and following land application. Concentrations of odorous gasses were measured using GC/MSanalysis and odor concentrations were determined using dynamic dilution olfactometry. Slurry concentrations of malodorousvolatile fatty acids were reduced by between 79% and 97% by anaerobic digestion, while concentrations of malodorousphenolic and indolic odor components above the slurry were reduced by both anaerobic digestion and subsequent separation.Odor concentration in air sampled above slurry stores was slightly reduced by anaerobic digestion; however, odorconcentration was found to be higher above stores of anaerobically digested slurry following mixing of the slurry prior toland application. Odor concentration in air sampled above land applied slurry was reduced by 17% by anaerobic digestionand by 50% by combined anaerobic digestion and separation.