Understanding Livestock Odors Ron Sheffield Animal Waste Extension Specialist

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

9. 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

10. 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

11. 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

12. 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

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

14. 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

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

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

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

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

20. 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

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

22. 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

23. 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

24. 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)

25. 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

26. 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

27. 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

30. 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

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

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

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

34. Odor Intensity

35. 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

36. 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

38. Terrain Influence on Dispersion

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

40. 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

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

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

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

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