Evaluation of additive for reducing gaseous emissions from swine waste
Keywords:Hog, Mesocosm-scale, Methane, 2-butanone, Tetrahydrofuran, Volatile fatty acids, Toluene
Additives can reduce gaseous emissions from swine waste lagoons and pits. We have demonstrated for the first time that an additive has the potential to reduce methane emission from an anaerobic swine lagoon. ManureMax®, a humate product was evaluated for its ability to reduce gas and odor emissions from swine anaerobic lagoon and barn flush-water. Four treatments, Control (no additive), Low (label dosage), Medium (50% higher than label dosage), and High (200% higher than label dosage) were applied to inclined pipes installed in a swine lagoon. While the Medium and High treatments were not effective, the Low treatment reduced methane, 2-butanone, and tetrahydrofuran concentrations by 34%, 44%, and 57%, respectively vs. the Control in the pipe headspace. Surface treatment was effective on methane for four weeks. ManureMax® was ineffective in reducing nitrous oxide and carbon dioxide concentrations in the headspace. It is unclear why only the Low treatment reduced concentrations of these gases in the lagoon though at least one study also reported similar findings with additive dosage. The Low treatment reduced chemical oxygen demand and total phosphorus in the lagoon supernatant probably due to chelation, flocculation, and/or oxidation. Applying treatments to pipes installed in a lagoon could be cost-effective way to compare treatments in replicated, mesocosm-scale studies in a lagoon. In the lab, all ManureMax® treatments reduced accumulation of three short-chain volatile fatty acids (VFAs) in the headspace of incubated glass bottles but only the High treatment reduced toluene accumulation (by 26%). The ability of ManureMax® to degrade long- and branch-chain VFAs requires further evaluation and its odor reduction potential should be tested using olfactometry.
Keywords: hog, mesocosm-scale, methane, 2-butanone, tetrahydrofuran, volatile fatty acids, toluene