Potential Air Quality Impacts of Anaerobic Digestion Of Dairy Manure

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Proceedings available at: http://www.extension.org/67666 Anaerobic digestion (AD) of livestock manure is better known for the economic return derived from biogas for energy rather than for its, inherent, environmental benefits. The effect of AD of dairy manure on the emissions of odor, ammonia (NH3), and greenhouse gases (GHG) including: carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4), during manure storage and also in subsequent land applications will be presented. Air samples were collected in 10-L Tedlar bags, at pertinent locations within the AD system, and shipped immediately to the lab for odor analyses by a trained odor panel using the Dynamic Dilution Forced-choice Olfactometer. Measurements of GHG emissions from both AD and non-AD manure storages were made using a floating chamber and a photoacoustic gas analyzer (INNOVA model 1412). Emissions of GHG were determined using the standard closed chamber method from field plots applied with AD and non-AD manure. Although odor analyses of collected air samples indicated increased detection threshold (D/T), odor strength (intensity) and unpleasantness (hedonic tone) decreased after AD of manure. Data indicated significantly higher fluxes of GHG from land applied with non-AD manure than from land applied with AD manure. Injection of non-AD manure further increased CH4 flux from applied manure. More than 50% emissions of CO2 and CH4 were observed during the first 3 days after manure was land applied. Emissions of GHG from the anaerobic lagoon holding AD manure, during all four seasons, were significantly lower than from the anaerobic lagoon with non-AD manure. In contrast, the reverse was observed with NH3 emissions suggesting potential increased emissions of NH3 during storage of post AD manure.

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<ul><li> 1. Potential Air Quality Impacts of Anaerobic Digestion ofDairy Manure Washington State University:H.S. Joo, P.M. Ndegwa, J.H. Harrison, E. Whitefield, S.Fei, X. Wang, G. NeerackalPurdue University: A.J. Heber, J.Q. Ni Waste-2-Worth Conference Denver, Co, April 3, 2013</li></ul> <p> 2. Outline Background Objectives of the study Materials and Methods Results Summary &amp; ConclusionsWaste-2-Worth ConferenceDenver, Co, April 3, 2013 3. Background This study is funded under NRCS-CIG program todemonstrate the impact of anaerobic digestion (AD) of dairymanure on air quality during effluent storage and/orsubsequent manure application on land. Motivation: The environmental benefits of AD has beenshown in research but adoption of the technology is still low. Interests: Odor and VOCs emissions, Greenhouse gases (GHGs) emissions, NH3 and H2S emissions.Waste-2-Worth ConferenceDenver, Co, April 3, 2013 4. Methods and Materials: AD site planComposting Solids separationvessel Manure from DairySolids/compost Generator Liquid Roomeffluent AD Mixingtank LagoonsWaste-2-Worth ConferenceDenver, Co, April 3, 2013 5. Methods and Materials: AD siteElectricitygeneratorSolids/liquidseparator ADCompostingdrums Receiving/mixing tankLiquideffluenttank Primary lagoonWaste-2-Worth ConferenceDenver, Co, April 3, 2013 6. Manure application plan/strategy in the plotsMethods and Materials: InjectedAD InjectedAD InjectedADManure applicationDrag hose applicatorBroadcasted Broadcasted BroadcastedNon-ADNon-ADNon-ADBroadcasted Broadcasted BroadcastedADADAD 125 ftInjectedInjectedInjectednon-ADnon-ADnon-AD28 ft Evacuated vialsChamber in place Waste-2-Worth Conference Denver, Co, April 3, 2013 7. Methods and Materials:Lagoon measurementsPhotoacoustic gas analyzer (INNOVA model 1412)Floating chamber Chambers access Waste-2-Worth Conference Denver, Co, April 3, 2013 8. Methods and Materials:Lagoonand Land Application Simulations in the lab. Waste-2-Worth Conference Denver, Co, April 3, 2013 9. Methods and Materials: Odor samples Air samples were collected in 10-L Tedlar bags. Effluent Separator At: Raw ADmanure, influent, effluent, aInfluent nd separated liquid.Receiving/mixingLiquid effluent tank Samples shippedtank immediately to the lab for odor analyses by a trained odor panel (Overnight). Dynamic Dilution Forced- choice Olfactometer. Waste-2-Worth Conference Denver, Co, April 3, 2013 10. Results: Land application (field studies) 10 800AD-Broadcast: R = 0.97 AD-Broadcast: R = 0.99 CO 2 Concentration (ppm) CH 4 Concentraion (ppm) 8NonAD-Injection: R = 0.94NonAD-Injection: R = 0.97600AD-Injection: R = 0.92 AD-Injection: R = 0.97 6NonAD-Broadcast: R = 0.95NonAD-Broadcast: R = 0.99400 4200 2 0 0015304560 0 15 30 45 60Time (minutes) Time (minutes) 2.5AD-Broadcast: R = 1.00N 2 O Concentration (ppm) 2NonAD-Injection: R = 0.99AD-Injection: R = 0.93 1.5NonAD-Broadcast: R = 1.00 1 0.5 0 015304560Time (minutes) Waste-2-Worth Conference Denver, Co, April 3, 2013 11. 2000 AD-Broadcast NonAD-InjectionCO2 Emission (mg/kg-VS) Results: Land application AD-Injection1500 NonAD-Broadcast emissions (field studies)1000 6000CH4 Emissions (g/kg-VS) 500 5000 AD-Broadcast 40000 NonAD-Injection 0 24 6 8 10 12 14 AD-InjectionTime (day) 3000 NonAD-Broadcast 2000 8000 AD-Broadcast NonAD-Injection N2O Emission (g/kg-TAN) 1000AD-Injection6000 NonAD-Broadcast 00 2 4 68 1012 144000 Time (day)20000 0 246 810 12 14 Time (day)Waste-2-Worth ConferenceDenver, Co, April 3, 2013 12. Results: Land application Ammoniaemissions (field vs. studies)1500 Field studies 80Lab simulation studies Cummulative NH3 emission1200Cummulative NH 3 emission 60 AD-INonAD-I 900 AD-BNonAD-BNonAD-B NonAD-IAD-BAD-I(mg) (ppm) 40 600 20 300 0 0 0 12 34 5 6 70 100 200 300 400 500Time (day)Time (h) Note the higher ammonia loss from non-AD surface applied manure contrary to what one would anticipate or expect!Waste-2-Worth ConferenceDenver, Co, April 3, 2013 13. 20 AD nonAD15 Results: Lagoon GHG EmissionsN2 O (g/m2 /min)10 5 30 0 April-MayJuly September NovemberCH4 (mg/m2 /min) AD nonAD 20AD 90 nonADCO2 (mg/m2 /min) 1060 30 0April-May July September November0April-May July SeptemberNovemberWaste-2-Worth ConferenceDenver, Co, April 3, 2013 14. Results: Lagoon NH3 Emissions1.2 Field studies0.9NH 3 (mg/m2 /min)ADnonAD 2000Lab simulated studiesRM Cummulative NH3 emission (mg)0.6 AD Influent 1600AD EffluentAD Liquid Effluent0.31200 800 0April-MayJuly September November 400AD effluent liquid after separation 0probably huge volatilization or loss occurs 0 51015Time (Day) 2025during solids-liquid separation process.Waste-2-Worth ConferenceDenver, Co, April 3, 2013 15. 6000 4500OUE/m3 3000 Results: Odor Analyses1500 0Water (Control) Raw ManureAD Influent AD Effluent AD Liquid Effluent 4.0 3.0Intensity 6-point Intensityscale: 2.0 1.01very weak2weak 0.0Water (Control) Raw Manure AD Influent AD Effluent AD Liquid3distinctEffluent4strongHedonic tone a0.0 5very strongnine-point scale: Water Raw ManureAD Influent AD EffluentAD Liquid (Control) Effluent 6extremely-4:extremely strong-1.0unpleasant to 0 orHedonic Tone-2.0neutral) to+4:extremely-3.0pleasant -4.0-5.0 Waste-2-Worth Conference Denver, Co, April 3, 2013 16. Summary &amp; Conclusions Emission of CO2 was much higher from non-AD manure compared with ADmanure. Injection of manure did not seem to play a major part on CO2emissions. CH4 emission was also much higher from non-AD manure compared with ADmanure. Injection of non-AD manure increased emissions of CH4. N2O emissions were slightly higher from non-AD manure compared with ADmanure. Injection of either AD or non-AD manure did not seem to affectemissions of N2O. Although AD manure had more TAN, NH3 emissions were highest in surfaceapplied non-AD manure!Waste-2-Worth ConferenceDenver, Co, April 3, 2013 17. Summary &amp; Conclusions GHG emissions from the anaerobic lagoon holding AD manure, duringall four seasons, were significantly lower than from the anaerobiclagoon with non-AD manure. In contrast, the reverse was observed with NH3 emissions. This wasalso confirmed via lab simulation studies. While odor concentration (DT) increased some going through thedigester, the intensity and hedonic tone improved. AD of dairy manure prior to its storage and land applicationdemonstrate significant environmental benefits (GHGs, odor, NH3). Potential liability - increased NH3 emissions during storage.Waste-2-Worth ConferenceDenver, Co, April 3, 2013 18. Our sponsorsQuestions?Waste-2-Worth ConferenceDenver, Co, April 3, 2013</p>