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Published byCecilia Berenice Richard Modified over 9 years ago
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DEVELOPMENT AND APPLICATION OF AN INEXPENSIVE CHAMBER FOR ANALYSIS OF VOLATILE ORGANIC CARBON B.L. Woodbury, D.N. Miller, R.A. Eigenberg and J.A. Nienaber USDA ARS US Meat Animal Research Center, Clay Center, Nebraska USA B.L. Woodbury, D.N. Miller, R.A. Eigenberg and J.A. Nienaber USDA ARS US Meat Animal Research Center, Clay Center, Nebraska USA
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The Problem The Feedlot Environment Spatial & temporal variation: Moisture Temperature Soil characteristics Manure deposition Spatial & temporal variation: Moisture Temperature Soil characteristics Manure deposition
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The Problem Potential Gaseous Emissions from Feedlot Surface Amides Ammonia Methylamines Diamines Aromatics Benzoates Indoles Phenols Sulfides Hydrogen sulfide Methyl sulfides Alcohols (Straight & Branch Chain) Ethanol, Propanol, Butanol, etc. VFAs (Straight & Branch Chain) Acetate Octanoate Isobutyrate, Isovalerate
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Objectives Feedlot Surface Emissions Design a cost-effective headspace chamber suitable for laboratory and field studies Evaluate its flow characteristics Design a cost-effective headspace chamber suitable for laboratory and field studies Evaluate its flow characteristics
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Design Criteria Portable for use either in lab or field Internal distribution system to ensure completely mixed conditions Septa port for gas sampling (i.e., SPME) Acid trap to collect ammonia Calculate relative emission rates Battery operated Portable for use either in lab or field Internal distribution system to ensure completely mixed conditions Septa port for gas sampling (i.e., SPME) Acid trap to collect ammonia Calculate relative emission rates Battery operated
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The Design “The Real Salad Bowl Study” Hemispherical headspace chamber Measure VOC w/SPME Ammonia trap Hemispherical headspace chamber Measure VOC w/SPME Ammonia trap ItemCost Chamber$5.00 Air Pump$130.00 Bubbler$50.00 Battery$25.00 Connectors/Fan$190.00 Total$400.00
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Sampling Port With Septa Seal
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Inside View With Internal Mixing Fan
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Tracer Study Total headspace volume (V) 7.6 L Flow rate (Q) 1.18 L min -1 RT = V/Q 50 ml CH 4 injection pulse Analyzed using a GC/MS with HID detector Total headspace volume (V) 7.6 L Flow rate (Q) 1.18 L min -1 RT = V/Q 50 ml CH 4 injection pulse Analyzed using a GC/MS with HID detector
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Mass Balance
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CH 4 Break-Through-Curve At 1 dilution 32% At 3 dilutions 5% Ideal reactor 37 & 5%, respectively At 1 dilution 32% At 3 dilutions 5% Ideal reactor 37 & 5%, respectively 32% 5%
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Theoretical And Experimental Headspace Chamber Properties HRTV Q ( min)(L)(L min -1) Calculated6.57.61.16 Experimental6.37.31.16 HRTV Q ( min)(L)(L min -1) Calculated6.57.61.16 Experimental6.37.31.16
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Gaseous Output Microbiologist: One return port would be enough Engineers: Four would be better
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Gaseous Output Linear with manure surface area
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Conclusions Chamber design performed similar to an ideal continuous flow stirred reactor Concentrations measured at sampling port are indicative of concentrations anywhere in headspace Chamber was found to be reasonably stable over wide range of flow rates Linear with respect to surface area of manure Cost per unit approx. $400.00 Chamber design performed similar to an ideal continuous flow stirred reactor Concentrations measured at sampling port are indicative of concentrations anywhere in headspace Chamber was found to be reasonably stable over wide range of flow rates Linear with respect to surface area of manure Cost per unit approx. $400.00
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Laboratory Studies Field Studies Laboratory Studies Field Studies
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Laboratory Studies Fresh Manures: Cattle vs. Swine Cattle—Ground corn/corn silage Swine—Grower diet Abundance, peak area x 10 6 5 15 10 5 15 10 Run time, minutes 123459876
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Laboratory Studies Volatiles Composition & Cattle Diets Ground corn/corn silage diet Abundance, peak area x 10 6 5 15 10 5 15 10 Run time, minutes 123459876 Alfalfa maintenance diet
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Cattle—Ground corn/corn silage diet Laboratory Studies Manure Incubation Abundance, peak area x 10 6 5 15 10 Run time, minutes 123459876 5 15 10 5 15 10 Fresh Cattle—Alfalfa maintenance diet Swine—Grower diet Incubated Run time, minutes 123459876
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Manure can be from 10 to 100 times more conductive than typical soil Field Studies Precision Feedlot Surface Management TX RX S The transmitter coil (TX) is placed near the earth and is energized with an alternating current. The small currents induced into the earth generate a secondary signal which is picked up by a receiver coil (RX) at a distance S away. The ratio of the two signals gives a measure of the soil’s conductivity beneath the two coils. Electromagnetic Induction Principles
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Bunk Waterer Mound 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 October 2004 Bunk Waterer Mound June 2004 Bunk Waterer Mound July 2004
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Association of volatile solids (manure) to EC a
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Total Phosphorus
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Total Nitorgen
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Area based on Conductivity Less than 25% of the area is high conductivity High Conductivity = Manure Accumulation? HighLow
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Ammonia Flux Across Pen BUNK NH 3 flux M/m 2 /hr Sample Location MOUND Feedlot pen 8X more VOC
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Feedlot Survey in Cooperation with ARS- USDA, Bushland, TX Target our management strategies?
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Questions?
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