Deodorization of swine manure slurry using horseradish peroxidase and peroxides

Considering the development of highly confined piggery and increasing complaints about livestock manure odors, it is pressing to develop a practical way to reduce the odors. Peroxidase, which has been proved to be capable of removing toxic phenolic compounds from wastewater, may also be effective in deodorizing the swine manures. Horseradish peroxidase (HRP) (0.1-3.0 U/mL) with hydrogen peroxide (H(2)O(2), 0.5-6%) or calcium peroxide (CaO(2), 0.1-3.0g) was examined for the efficiency of controlling the release of seven malodor compounds, including three volatile fatty acids (isobutyric acid, isocaproic acid and isovaleric acid), two phenolic compounds (phenol and p-cresol) and two indolic compounds (indole and skatole) from swine manure slurry. Odor intensity and total nitrogen content in swine manure were also measured. The results showed almost 100% reduction in p-cresol, 54-84% reduction in odor intensity, 32-54% reduction in indolic compounds and 28-41% reduction of VFAs. The effect of deodorization can last for at least 48 h.