Effectiveness of Manure Pit Additive in Reducing Emissions and Solids

Abstract

HighlightsA simple design was applied to simulate long-term manure storage for pit additive effectiveness.Odor reduction was observed after six months, suggesting some additives take time to show effects.Low reductions of total solids and volatile solids were observed only for the 200% dosage treatment.Nutrient contents were not affected by the additive during the long-term storage.Abstract. Odor emissions have always been a challenge for intensive animal operations. Various pit additives continue to be developed and improved to mitigate odor and manure solids. A commercial, biological additive was evaluated in a laboratory setting for effectiveness in reducing manure solids as well as gas and odor concentrations. In a short-term experiment (Experiment 1), twelve 3.79-L (1-gal) glass jars were used to mimic semi-long-term manure storage. The experiment was conducted in triplicate with four treatments consisting of dosages of 0, 50%, 100%, and 200% of manufacturer recommendations. The stored manure was analyzed for pH, total solids (TS), and volatile solid (VS) contents, as well as ammonia (NH3) and hydrogen sulfide (H2S) concentrations. After the additive application method and dosages were verified, a long-term experiment (Experiment 2) was conducted in triplicate by using nine 15-cm (6-in.) ID, 1.52-m (5-ft.) long PVC reactors with different treatments: control, 100%, and 200% dosage. No statistical differences were observed for pH, NH3, and H2S between the control and treatment groups in both experiments. Low reductions of TS and VS were observed only for the 200% dosage group in Experiment 1. Odor concentration, after decimal logarithm transformation, was significantly reduced only at the 200% dosage treatment at the end of Experiment 2 (p < 0.05). Nutrient contents were similar among the groups, which confirmed that the additive did not alter manure nutrients during the long-term treatment period. Keywords: Deep-pit, Manure storage, Microbial activity, Mitigation, Odor.