Reducing odorous VOC emissions from swine manure using soybean peroxidase and peroxides

► Soybean peroxidase and peroxides were applied to swine manure for odor control. ► The optimum industrial-grade soybean peroxidase rate was 50gL−1. ► Calcium peroxide was more effective than hydrogen peroxide. ► The primary odorant 4-methylphenol accounted for 68–81% of the odor activity value. ► A 4-methylphenol reduction of 92% was achieved. The objective of the research was to determine the optimum application rates of soybean peroxidase (SBP) plus peroxide (SBPP) for reducing odorous VOC emissions from swine manure. Industrial-grade SBP was applied in combination with liquid hydrogen peroxide (H2O2) or powdered calcium peroxide (CaO2) to standard phenolic solutions and swine manure, and emissions were measured in a wind tunnel. The primary odorant in the untreated manure was 4-methylphenol, which accounted for 68–81% of the odor activity value. At the optimum application rate of SBPP (50gL−1), 4-methylphenol emissions were reduced from the swine manure by 62% (H2O2) and 98% (CaO2) after 24h (P