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Understanding Livestock Odors Ron Sheffield Animal Waste Extension Specialist

Understanding Livestock Odors Ron Sheffield Animal Waste Extension Specialist. Odors from Livestock Facilities. Odors from Livestock Facilities. Highly emotional issue Rural development Economic importance of livestock industry

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Understanding Livestock Odors Ron Sheffield Animal Waste Extension Specialist

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  1. Understanding Livestock OdorsRon SheffieldAnimal Waste Extension Specialist

  2. Odors from Livestock Facilities

  3. Odors from Livestock Facilities • Highly emotional issue • Rural development • Economic importance of livestock industry Only after we understand the problem can we work towards acceptable solutions.

  4. Olfaction-Sense of Smell • Complex • Evokes a reaction • Humans detect > 10,000 odors • Mixtures of gases • Able to detect extremely low concentrations

  5. Conception of Odors and Smells • Describe a childhood odor memory • What is your favorite odor? Why? • Describe your most unusual odor memory

  6. Breathing vs. Sniffing

  7. Normal Olfactory Sensitivity Ansomic Condition Hypersensitive Condition Population Detecting Odor (%) Normal Sense of “Smell” Odor Concentration

  8. How are odors produced? • By-products of microbial degradation of manure and organic matter • Uncontrolled anaerobic conditions • Highly dependent on the amount and type of microbial activity

  9. Manure Decomposition • Over 80 to 200 different gasses identified • Manure gasses related to anaerobic decomposition • Ammonia (NH3+) • Methane (CH4) • Hydrogen sulfide (H2S) • Odorants • volatile fatty acids • Dust and other particulate matter

  10. Manure Gasses • Hydrogen Sulfide • Methane • colder climates, poor ventilation, anaerobic decomposition of stored manure • Ammonia (NH3) • dominates in warmer climates • anaerobic by-product • compounded by recycling of lagoon effluent for waste handling

  11. Dust • Sources • Feed • Dried Manure • Dander (dead skin) • Hair • Other particulate matter • viral, bacterial, and fungal agents • endotoxin, glucans • Dual role as possible odorant and odor carrier

  12. Odor and Gas Emissions • Parameters that effect odor and microbe production • moisture content • temperature • pH • oxygen concentrations • environmental conditions (season, wind patterns)

  13. Manure Gases • Nose detection at low levels • Hydrogen Sulfide (H2S) • Nose detection at high level • Methane (CH4) • Some gases may have a compounding odor effect

  14. Odor Emission Sources • Livestock buildings • Manure storage units • Land application sites • Method of land application • Feed storage • Mortality storage or disposal units

  15. Odor Sources • “Background” odor • buildings • lagoons or storage ponds • Seasonal variations in odor • “Short-term” odors • agitation • land application / spray irrigation

  16. Odor and Gas Emissions • Can be controlled through design and management • ventilation system • management and “housekeeping” practices • waste management system • waste application system

  17. Odor Chemistry • Odorous Compounds • Aliphatic (fatty) Acids • Amines • Ammonia • Aromatics • Sulfur (inorganic and organic)

  18. Compounds Produced through Anaerobic Decomposition • Methane • Carbon Dioxide • Carbon Monoxide • Ammonia • Hydrogen Sulfide • Acetic, Propionic, Butyric Acids • Cadaverine and Putresine - bacterial breakdown of amino acids

  19. Osmophores • Odors are caused by this group of radicals CHO- Aldehydes CH2OH- Carbinols CO-2 Carbonyls COOH- Carboxyls OH- Hydroxyl compounds SH- Sulphydryls

  20. Osmophores • Odor/smell is due to the presence of different molecules C2H5OH Ethyl Alcohol, sweet-smelling C3H5OH Allyl Alcohol, irritating smell C9H19OH Nonyl Alcohol, offensive smell

  21. Oxygen Transfer • Replacement of oxygen by sulfur • Non-odorous compounds H2O Water H2O2Hydrogen Peroxide CO2 Carbon Dioxide • Compounds become odorous H2S Hydrogen Sulfide H2S2Hydrogen Persulfide CS2 Hydrogen Disulfide

  22. Biochemical Oxidation • Proteins, amino acids & carbohydrates are plentiful energy source for bacteria • Aerobic or anaerobic process • Bacteria “transfer” oxygen from compounds to a hydrogen acceptor 2NO3- + 12H+ = N2 + 6H2O CO2 + 8H+ = CH4 + 2H2O SO4 + 10H+ = H2S + 4H2O (odorous)

  23. Purple Sulfur Bacteria - PSB • Biochemical Oxidation in Anaerobic Lagoons in NC and southern US • Purple lagoon color • Photosynthetic bacteria • Use H2S as an electron acceptor instead of O2 and NO3 • Reduces emission of sulfur compounds and sulfur based odors

  24. Sun Light-dependent reactions (photophosphorylation) ATP NADPH + H+ Dark reaction (CO2 fixation) CO2 Carbohydrates Photosynthesis Oxygenic: Green plants, algae, cyanobacteria Anoxygenic: Purple, green and Heliobacteria Sun Light-dependent reactions (photophosphorylation) ATP H2S Dark reaction (CO2 fixation) CO2 Carbohydrates *** H2O is electron donor *** H2S is electron donor

  25. Anaerobic Lagoons • Studies have been inconclusive relating environmental conditions to the presence of PSB in lagoons • loading rate (TS, VS, NH3, SO4) • class of animals • Temperature • Lagoon start-up procedures

  26. Odors and Gases • Odor Intensity • measure of detection sensed by the nose • Gas Concentration • actual concentration of gas in the air • The relationship between odor intensity and gas concentration is different for each gas

  27. Gas vs Odor Measurement • Gas • Identify individual gases • Measure concentrations • Odor - Olfactometry • Analyze mixture • Correlates with odor • Uses human sense of smell

  28. Gas Measurement • Instantaneous • Integrated average • Precision & detection limit

  29. Gas Measurement • Patches • Tubes - Indicator & Diffusion • Jerome® meter - H2S • Electronic Sensors • GC / Mass Spectrometer

  30. Odor Intensity

  31. Odor Intensity vs. Gas Concentration • Weak positive correlation's for some gases • Ammonia (NH3) • Hydrogen Sulfide (H2S) Example: • High odor intensities indicate high gas concentrations of NH3 and H2S • However, high gas concentrations do not necessarily indicate a high odor intensity

  32. Odor Transport • Difficult to document the impact area of gases • Transmitted via air currents • wind direction • wind speed • weight of gas • adsorption to dust particles

  33. Terrain Influence on Dispersion

  34. Lagoon Dust & Lagoon Interaction Related to Odor Transport Dust Odorous Compounds

  35. Limits to Measuring Odors • Changes in weather or micrometeorological conditions • temperature, humidity, inversions • Odor emissions change with time • Wind speed and direction • A snap-shot in time may not reflect the conditions an hour/day before or after a measurement

  36. Technologies to Control Odor • Prevent odor generation • Capture or destroy odors before any release to the atmosphere • Dispersion or disguise of odors

  37. Odor Prevention Technologies • Anaerobic treatment • Aeration or Oxidation • Feed additives • Manure pit or lagoon additives • pH control

  38. Technologies to Capture Odors • Manure storage covers • synthetic • organic mats • Biofilters • Biomass filters • Washing walls

  39. Technologies to Disperse Odors • Site Selection • Ventilation Design • Vegetated Wind Breaks • Windbreak Walls • Stacks or Chimneys • Perfumes • Masking Agents

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