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Livestock and Air Quality CAFO Air Emissions Project CSU-ARDEC Feb. 9, 2006 Animal Science (Johnson, Stanton, Marcillac) NREL (Hannan) ARS (Mosier/Follet Atmospheric Sci. (Collet, Lee)
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National Academy of Science NRC 03 Air Emissions from AFO’s Commissioned by EPA and USDA Finding 7: methods and measurements needed for NH3, CH4, H2S, PM’s Finding 8: Emission factor estimates not adequate Finding 9: Process-based model development recommended
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National Research Initiative USDA 2004 RFP $ for Air Quality studies ? How can AFO emissions be measured? Particularly variable, heterogeneous production systems; e.g., cattle, pens, dams, lagoons, composting of all shapes sizes, etc We have a team that thinks we can!
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Air Emissions from dairy CAFO: multi-scale measurements and process-based modeling The overall aim: to measure potentially problematic air emissions from cattle production systems and develop process based methods to predict them.
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Specific Objectives 1. Measure emissions from 2 dairies: –Ammonia – PM 2.5 –Nitrous oxide –Methane 2. Determine diurnal, seasonal variations 3. Develop and challenge process model estimates of emission fluxes
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Objectives Contd: 4. Correlate downwind concentrations of spot sampled emissions - e.g.: H 2 S, VOC’s..
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Approach Quantification of CAFO System Emissions –Mass Balance
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F0F0 F1F1 FeFe FdFd F S x,y = dc/dt x,y,z + { F 1 y,z – F 0 y,z } + { F l x,z } + { F e x,y + F d x,y } dc/dt x y z Whole-System Trace Gas Fluxes from Complex Agricultural Sources: Plume Characterization and Conservation of Mass FSFS FlFl PlumeLateralVertical Primary wind direction indicates summation across plane or volume indicated by subscripts
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F0F0 F1F1 FdFd Tethersonde Array T a, q, u, [CO 2 ], [CH 4 ], [N 2 O], [NH 3 ], PM 10, PM 2.5 F S x,y = { F 1 y,z – F 0 y,z } + { F d x,y } 1 sonde to characterize background profile, 3 (or more) to characterize plume, chemical trap array Sonde telemetry to central computer. Balloon specs: >1 km height, 5 kg payload, auto-deflate ?
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Tethersondes and Air Sampling Tethersondes at 5 heights; wind-speed, direction, humidity, temperature and pressure. Sample lines at 5 heights –draw samples to ground for non-reactive gases (CH 4, N 2 O, CO 2 ) –filters attached at each sample height collect NH 3, PM2.5, nitric acid. Sample; 1-2hr, 3X/d, 2 days, 7 seasons, 2yr
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DW3 Upwind DW2 Date Temp, ºC RH, % Wind Speed, mph Wind Dir, º Nov 1811.326.82.3348.3 Sample Dairy 1 DW1
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F 0 = y ∫ u z c z dz F 1 = ∫ ∫ u y,z c y,z dy dz Fluxes F 0 and F 1 : Planes Perpendicular to Wind Direction T a, q, u, [CO 2 ], [CH 4 ], [N 2 O], [NH 3 ], PM 10, PM 2.5 help Fluxes estimated by fitting flux velocity planes to measured scalar concentration and wind speed profiles and estimating the integrals dc/dt x y z czcz czcz
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Approach Process-based Model Characterization of Emission Source Components –Animals, diets, pens, manure removal methods, solids separation, lagoons, composting procedures –Prediction of C and N flux through each Modify whole farm model: –No cropping, add composting, NH4
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Products and GHG from Cattle Production J W Herd 100 cows + others Cropping Feeds Manure CH 4 N 2 0 Fuel C0 2 Soil Carbon ( + )
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Figure 1. Estimates of source and intensity of greenhouse gas emissions per unit of milk, lbs/lb, by scenario from Colorado dairy cattle systems.
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Products and GHG from Cattle Production J W Herd 100 cows + others Cropping Feeds Manure CH 4 N 2 0 Fuel C0 2 NH4 PM ( + )
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Important questions NH 3 amounts by source NH 4, conversion to PM’s CH 4 from lagoons, dams, composting N 2 O from each Variations: diurnal, season, temp, etc
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Total cost of US livestock NH 3 and CH 4 (Sci. 05, 308:1901) NH 3 : EPA 04 estimate –2,418,595 t/yr X $1.3 to $21/kg = 3 to 50 $Bill/yr Note: McCubbin 02; 10% Livstk NH 3 $4B CH 4 : EPA 04 estimate: –7.3 Tg/yr X $0.60 to $1.54/kg = 4 to 11 $Bill/yr
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The next step: Mitigation Treatment effects; algae, aeration, CuSO4, etc, etc. Dietary comp: RDP, peptide, Bypass AA’s, CHO source and Kd, etc, etc
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All Emission Mitigation Approaches Must: be based on a comprehensive, life cycle analysis that assesses all emissions; ammonia-PM2.5, greenhouse gases,etc.
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Potential for Ammonia reduction Diet crude protein effect: Two research report examples: –Kulling,01 Dairy –Cole, 04 Beef
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NH 3 from manure of steers vs %CP in diet (Cole, et 05) Manure-soil incubations: Diet %CPNH 3 Control14.50 Med13.0- 37% Low11.5- 63%
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Diet %CP vs Ammonia loss (Kulling,et. 01 J Ag Sci 137:235) Lactating Cows, 30.9 kg/d, 3 protein levels, +bypass Methionine 12.5 % 15 % 17.5 %
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Dairy % diet CP vs NH 3 Emissions (Kulling 01, J Ag Sci 137:235)
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Environmental Stewardship Strategies for Livestock production systems Reductions in excess N - Primary Reductions in feed/product Dilution of maintenance Reduction of maintenance Mitigation strategies should consider all emissions
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