Swine Manure Odor Removal Using Biochar.

Malodorous emissions from livestock operations disrupt quality of life in rural and urban communities. The objective of this study was to evaluate the potential of various biochars to be used as a sorbent for removing odorants from swine manure storages. Pine, oak, solid-separated swine manure, swine compost, coconut shell, and poultry litter were selected as biomass feedstocks for producing biochar. Pellets of each of these biomass feedstocks were pyrolyzed at 350 ^oC and 500 ^oC using a Lindburg electric box furnace equipped with a gas tight retort. Some of these were also partially activated with steam at 700 ^oC. Biochar samples from swine manure compost and imported coconut shell char were also steam activated using a commercial rotary kiln system in Korea. All biochar samples were analyzed for their elemental compositions, volatile matter, fixed carbon, ash contents, size, density, and surface area. Odorous volatile organic compounds (VOCs) were pre-concentrated using pre-conditioned stainless steel sorbent tubes filled with Tenax TA® sorbent. Sorbent tube samples were then analyzed using a thermal desorption-gas chromatography-mass spectrometry system. Manure samples from finishing swine farms with flushed (North Carolina) and deep-pit (Kentuky) manure management systems were collected from commercial swine farms. For each sorption experiments, about 2.5 L of these manure samples were placed in a 19L sealed plastic container. Ultra-pure N₂ continuously flushed the headspace of the sealed container at flow rate of about 1.1 L/min. The flushed headspace gas of the sealed container entered a sorption column filled with specific biochar samples. Sorption capacities of each odorants were calculated from influent and effluent odorant concentrations, biochar mass and the N₂ flowrate. The results of these laboratory experiments such as biochar properties, odor characteristics, and sorption capacities of different biochar for different odorants will be presented at the symposium.