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Gaseous Production from Impermeable Swine Waste Storage Tanks and its Abatement Using Biofilters
G. B. Day, A. Singh, S.F. Higgins
Department of Biosystems and Agricultural Engineering
Animal feeding operations (AFOs) are a source of air borne contaminants including ammonia, methane, nitrous oxide, hydrogen sulfide and dust, which contribute to air and water pollution. A major source of pollutant gases on an AFO is manure storage. Structures used to store manure prior to land application include deep pits and anaerobic lagoons. However, impermeable manure storage structures are a positive alternative for Kentucky's swine operations particularly those located in hydrosensitive karst (limestone) geographical regions.
Because there is little data regarding gases produced and emitted by manure stored in impermeable structures, this project seeks to characterize gas production and apply biofiltration technology to reduce emission of noxious gases. Biofilters have not been tested for their efficiency in eliminating manure gases in ventilation air exhausted from impermeable manure storage tanks. It is expected that air pollution will be reduced if the stored swine waste is covered and ventilated and the exhaust air is treated by biofiltration prior to discharge.
A long-term goal of this project is to promote liquid manure storage in environmentally sound impermeable tanks coupled with biofilters to reduce air and water pollution. This study evaluates gaseous production rates from dilute stored swine waste, and the ability of biofilters to reduce the emission of these gases into the environment.
2009 Project Description
ACTIVITIES: Experiments were conducted to determine the effects of moisture content on ammonia(NH3)removal capacity and nitrous oxide (N2O) production in compost biofilter material used in the abatement of greenhouse gases (GHG) from enclosed liquid swine manure containment facilities. Physical and chemical analyses were performed in addition to longer-term gas monitoring studies. A companion moisture loss experiment was performed in addition to the gas monitoring work as a means of minimizing the impact of moisture measurement on gas activity. The degradation of NH3 and the production of N2O were investigated for constant air flow rate and relative humidity, particle size, and initial gas concentration. Moisture conditions were varied from no moisture replacement to moisture added based on estimates of evaporation and drainage. Porous soaker hoses and control valve systems were calibrated for pressure and flow for use in an automatic moisture control strategy in the pilot-scale system. New materials were investigated for use in the refinement of a capacitance-based sensor system which will be imbedded in the compost to provide feedback to the control loop. A companion device to the bioreactor cabinet was designed to provide volumetric gas production measurement capability. A commercial producer in central Kentucky was identified to provide liquid waste at approximately 5% solids content in addition to fresh manure directly from the floor. This material is combined to create nutrient stock at 5%, 9%, and 12% solids content for use in the bioreactors.
EVENTS: Papers were presented at the 2009 SIGERA, 1st International Symposium on Animal Waste Management in Florianopolis, SC, Brazil, March 11-13.
PRODUCTS: Work was nearly completed on one PhD program on studies involving the effect of moisture on ammonia and nitrous oxide production. An effective collaboration was established with the NRI Research Group at the University of Illinois at Urbana Champaign. Student research projects from UK and UIUC aimed at solving moisture control in compost biofilters are now working together to maximize results and minimize costs. A newly constructed Volumetric Production Instrument (VPI) was installed online with a bioreactor cell to provide gaseous production rates in addition to constituent analysis.
Moisture content within the stack was shown to be critical in the laboratory scale biofilters. Extensive analysis indicates strong correlation between moisture content, NH3 removal and N2O production. High moisture levels (at or near water holding capacity) provide optimal conditions for NH3 removal and tend to minimize N2O production. Insufficient moisture levels (at or near the absence of free water) were characterized by rapidly decreasing ammonia removal capability and significant increases in N2O production. Material-specific values for moisture content, NH3 removal, and N2O will be published in a doctoral dissertation in April 2010. A chamber of the bioreactor cabinet was charged with approximately 72 liters of swine waste. Measurable gas production was evident within the first 6 to 8 hours, however, data for the gas production research is incomplete at this time.
Sales, G.T.,G.B. Day V, R.S. Gates, N. Lovanh, G. Del Nero Maia, and A. Singh. 2009. Assessment of Biofilter Media Particle Sizes for Removing Ammonia. Presented at the Simposio Internacional sobre Gerenciamento de Residuos de Animais SIGERA. (1st International Symposium on Animal Waste Management). March 12th & 13th, 2009. Florianopolis SC, Brazil.
Del Nero Maia, G., G.B. Day V, R.S. Gates, J. Taraba, and N. Lovanh. 2009. Ammonia Removal and Nitrous Oxide Production in Gas-Phase Biofilters. Presented at the Simposio Internacional sobre Gerenciamento de Residuos de Animais SIGERA. (1st International Symposium on Animal Waste Management). March 12th & 13th, 2009. Florianopolis SC, Brazil.