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Odor Has insignificant effects on the global or national environment Has major effects on the local environment –Nearest dwelling –Greatest source of nuisance.

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Presentation on theme: "Odor Has insignificant effects on the global or national environment Has major effects on the local environment –Nearest dwelling –Greatest source of nuisance."— Presentation transcript:

1 Odor Has insignificant effects on the global or national environment Has major effects on the local environment –Nearest dwelling –Greatest source of nuisance complaints Operations % of nuisance complaints from odor Swine 95 Broiler 75 Layer 66 Beef feedlots 50 –Sources Animal buildings and lots Manure treatment and storage Land application Silage Feed processing Dead animal disposal –Difficult to define, quantify, and control Odor composed of 331 compounds in manure –30 compounds most common in swine manure

2 Most objectionable compounds in manure Odor threshold ___Class___ ___Compound___ ____Smell_____ ____ppm____ Substrate Volatile fatty Butyric acid Rancid butter.001 Carbohydrate Acids Isobutryic acid Rancid butter - Protein Caproic acid - - Carbohydrate Isocaproic acid - - Protein Valeric acid Putred fecal - Carbohydrate Isovaleric acid Stinky feet - Protein Propionic acid Intense vinegar 20.0 Carbohydrate Phenylpropionic acid - - Protein Lauric acid - - Carbohydrate Acetic acid Vinegar 1.0 Carbohydrate Ammonia and Ammonia Acrid 46.8 Protein Amines Putrescine Rotting flesh - Protein Cadaverine Rotting flesh - Protein Trimethyl amine Protein Trimethyl pyrazine - - Protein Tetramethly pyrazine - - Protein Indoles and Indole Intense fecal - Protein Phenols Skatole Nauseating fecal - Protein Phenol Protein Ethyl phenol - - Protein p-Cresol Major odor in swine manure.001 Protein

3 Odor threshold ___Class___ ___Compound___ ____Smell_____ ____ppm____ Substrate Sulfur-containing Hydrogen sulfide Rotten eggs.0072 Protein & TM Compounds Dimethyl sulfide Rotten eggs.001 Protein & TM Diethyl sulfide - - Protein & TM Methyl mercaptan Skunk.002 Protein & TM Ethyl mercaptan Skunk.001 Protein & TM Common divisions used in discussing odors –NH 3 –H 2 S –Volatile organic compounds No single chemical has been identified as a good indicator of odor Difficult to control odor by any single approach

4 Measurement of odor –Gas measurement Air samples are collected and analyzed for specific, individual gaseous compounds Measured with: –Patches –Indicator tubes –Meters –Electronic sensors –Gas chromatograph/mass spectrometer Advantages –Accurate measure of individual gases »Allows for specific numeric standards »Useful for measuring gaseous compounds with specific health effects Limitations –Manure odor is not associated with any single compound

5 –Olfactometry Odors are measured by a trained panel of humans May be measured –On location »Scentometer »Field sniffer –In laboratory »Dynamic, triangular forced-air olfactometer Characteristics to describe odor –Concentration »Detection threshold Volume of normal air needed to dilute odor sample to the point where the difference is detected by 50% of the panel members »Recognition threshold Volume of normal air needed to dilute an odor sample to the point that the panel can recognize the compound –Intensity »Describes the strength of the odor relative to different concentrations of n-butanol –Persistence »Amount of air needed to dilute air around a livestock unit to the point where the odor is not smelled

6 –Hedonic tone »Measurement of the unpleasantness of an odor »Scale of measurement is 1 to 10 –Character descriptors »A description of the smell Advantages –There is a direct correlation between odor and the sense of smell –Measures the complete mixture of gases Limitations –Olfactometry is subjective »Imprecise »Difficult to regulate

7 Health effects of odors –Within buildings Toxicity of two compounds –Ammonia –Hydrogen sulfide Ammonia Concentrations, ppm Exposure ________Effects____________ 20 - Decreased disease resistance 50 < 1 day Eye and throat irritation Severe cough weeks Impaired pulmonary function <150 < 1 day Scarring of upper and lower airway min Sore nose and throat < Irritation of upper respiratory tract > Severe damage to upper and and lower respiratory tract 5000 < 30 min Death –Smells at 50 ppm

8 Hydrogen sulfide –Most dangerous of gases –Colorless –Can be smelled at 1 ppm, but concentrations > 150 ppm inhibits smell »Makes H 2 S particularly dangerous »Requires monitoring equipment –Gas is heavier than air »Concentrates in pits and holding tanks »Dangerous when agitated –Acute toxicity Concentration, ppm Exposure Human effects Swine effects 100 > 1 hr Eye and nose irritation None hr Headache, dizziness hr - Pulmonary edema min Nausea, excitement, - insomia >500 - Severe pulmonary edema Unconsiousness, Spasms, convulsions death cyanosis, death –Chronic toxicity »Occurs at long-term exposure at 300 ppm »Symptoms Asthma, bronchitis, sinusitis, hay fever, progressive loss of lung function, chronic obstructive pulmonary disease

9 –Effects of H 2 S on lungs are uniform throughout the respiratory tract »Particularly damaging to deep pulmonary structures, causing edema –Toxicity effects »Binds mitochondrial cytochrome oxidase »Blocks oxidative phosphorylation and ATP production »Causes build up of lactic acid in body »Neurophysiological abnormalities Impaired balance Impaired hearing Impaired memory Impaired mood Impaired intellectual function –Workplace limit »10 ppm H 2 S

10 –Community effects Response to NH 3, H 2 S, and VOCs Symptoms –Headache –Runny nose –Sore throat –Coughing –Diarrhea –Burning eyes –Negative mood (Tension, depression, anger, fatigue, confusion) Odor recommendations –Based on dilution ratio of clean air:air from livestock operation –Odor shall not exceed a 7:1 dilution at a residence in two periods/day for more than 7 days per year –Odor shall not exceed a 15:1 dilution at the property line for one period/day for more than 14 days per year Factors affecting odor complaints –Frequency of problem »86% of farmers tolerate neighbor’s odor if problem occurs > 2 days/year »50% of farmers tolerate neighbor’s odor if problem occurs > 10 days/year –Intensity of problem –Duration of problem –Offensiveness of odor –Relations with neighbors (Time of residence, previous contact) –Odor plume (Direction, topography)

11 Origin of livestock odor Odor compound Large intestine Carbohydrates Protein (Starch, cellulose) Volatile fatty acids (Acetic, Propionic, Butyric acids; may be absorbed or excreted) H 2 S and mercaptans (Passed as gas) Other amines, phenols, and indoles (Absorbed from LI & excreted in urine) Manure Carbohydrates (Secondary Volatile fatty acids and alcohols Protein fermentation Lactic acid greater at: Butyric acid Manure pH > 4.5; High manure moisture; NH 3, H 2 S, mercaptans, branched High ambient temperatures) chain VFAs (Isobutyric, Isovaleric), CH 4 Amines (Putrescine, Cadaverine), Phenols (Phenol, p-Cresol), Indoles (indole, Skatole) Air Emissions increased with increased temperature, moisture, humidity, agitation, dust, pH, wind, surface exposure

12 Livestock management to reduce odors –Reduce excessive protein feeding Reducing protein swine diets from 18 to 14% reduced odor components by 40 to 86% Nonruminants –Balance essential amino acids to create ideal dietary protein with crystalline amino acids –Use multi-phase and split-gender feeding –Avoid safety margins in protein feeding –Use genetically lean pigs –Use growth promoters –Minimize feed waste Ruminants –Supply only enough ruminally degraded protein to meet the NH 3 needs of the rumen bacteria –Beyond the microbial NH 3 needs, meet animal’s metabolizable protein needs with ruminally undegrade protein sources or crystalline amino acids –Use phase feeding of beef feedlot or dairy cows –Control feed wastes –Reduce sulfur in mineral supplements Can reduce odor by 40% Utilize salts other than sulfates or sulfides for trace minerals

13 –Increase cellulose or other nonstarch polysaccharides in swine diets Causes bacteria in large intestine to incorporate NH 3 into microbial protein Reduces NH 3 by as much as 35% Ingredients to add: –Soy hulls –Sugar beet pulp –Distillers grains –Mask odor with other odors Garlic powder has been used for poultry –Feeding sarsaponin Extracted from yucca plant Inhibits urease –Feeding zeolites Minerals that have cation exchange capacity –Binds odor compounds –Reduce dust from animals’ skin Increase quality of dietary fat Feed adequate zinc

14 Management of livestock facilities to manage manure odor –Frequent cleaning of wet manure and feed from facilities Manure standing for more than 5 days will cause considerable offensive odor –Use bedded systems Odor seems less offensive than liquid systems Addition of organic matter from bedding reduces odor –Reduce dust within and outside buildings Approaches –Frequent cleaning –Spraying vegetable oils »Reduce NH 3 and H 2 S by 30% »Spray once daily »Use a medium droplet size »Problem with oily facilities –Installation of wet scrubbers »Wetted pads 3 to 5’ in front of ventilation fans »Traps dust with some NH 3, H 2 S, and NOx »Effectiveness on odors? –Use of chemical additives Alum (K Al(SO 4 )) will reduce some NH 3 emissions

15 –Use Biofiltration A system that uses aerobic bacteria to degrade gaseous odors from ventilated air Process Aerobic bacteria VOC & inorganic gases CO 2 + H 2 O + Mineral salts + Microbial biomass Fiber mat serves as media –Shredded wood and compost (50:50) –Shredded wood and soil (50:50) –Straw and compost Less effective during periods of high ventilation Can be difficult to control vegetation and rodents

16 –Use Biomass filters Walls of corn stalks, corn cob or other materials placed immediately outside ventilation fans Effects –Reduces dust by 52 – 83% –Reduces odor by 43 – 90%

17 –Use windbreak walls Walls placed 10 – 20 ft downwind from ventilation fans Effects –Settle dust near barn –Disperses odor plume upward to increase dilution –Use natural windbreaks Rows of trees or other vegetation Effects –Trap dust –Aids in dispersion and dilution of odor –Provides a visual barrier

18 Management of manure storage to limit odor –Aerobic treatment Liquid manure –Air is pumped into liquid manure –Should oxidize odor-causing chemicals –Difficult to mix enough O 2 to be effective Solid manure –Composting »Requirements Appropriate moisture (50%) Adequate C:N ration (>20:1) Aerobic conditions (Frequent mixing) Temperature (130 o F for 3 days) –Oxidizes odor and incorporates N-containing compounds into microbial protein –Effects »Reduces odor by 75% in 2 weeks

19 –Management of anerobic lagoons Complete anerobic digestion is effective at limiting odors Odors can be controlled if: –Loading rate is slow and uniform enough to allow balance of bacteria producing VFAs or CH 4 »Allows development of purple sulfur-oxidizing bacteria Metabolize VOCs Reduce amines A purple or pink color of lagoon is desirable

20 Factors affecting odors in lagoons –High loading rates »Excess animal numbers »Inadequate dilution water –Windy conditions »Disturbs surface –Timing of agitation and pumping for application »Should be done on clear, sunny days when warm air causes odors to rise and disperse –Early spring turnover »Odor problems increase as bacterial action begins to increase digesting nutrients that were incompletely metabolized over winter

21 –Use covers over storage facilities Covers over manure structures –Rigid covers »Concrete, wood, fiberglass, plastic »Materials must be noncorrosive –Flexible covers »Tarp over manure with a blower Floating covers –Natural »Crust floating on top of manure –Artificial organic »Straw, chopped corn stalks, wood shavings –Artificial »Polystyrene foam, air-filled clay balls, geotextile –Effectiveness »Provides a barrier between liquid manure and the atmosphere »Provides aerobic media to all microbes to degrade odor compounds »Limitations Straw will only last from 2 weeks to 6 months

22 –Anerobic digesters Produce methane for biogas Reduce odors by 70 – 80% –Additives Biological –Microbial additives »Cultures added to degrade odor compounds »Effectiveness? Chemical –Oxidizers and pH control »Limited effectiveness –Masking agents »Volatile compounds that smell pleasant »Sprayed on or above manure »May separate from manure downwind –Absorbents and Adsorbents »Activated carbon, zeolite, bentonite, or sphagnum moss »Effectiveness? –Antimicrobial oils »Includes plant oils like thymol and carvacol »Inhibit microbial degradation of manure during anerobic storage, but degrade in aerobic conditions after application »Preserves nutrients and reduces odor emissions »Still in research »Economics?

23 –Natural windbreaks Creates a visual barrier Filters, disperses and dilutes odor –Separation of manure solids and liquid Can be mechanical or gravity Separates urea in urine from urease in feces Effects –Reduces NH 3 –Reduces odor by 50%

24 Manure application management to control odors –Manure odor problems are directly proportional to the surface area for emissions The area of manure application is the greatest source of manure odor –Factors affecting manure odor during application Form of manure –Earthen basin > Below barn pit > Anerobic lagoon > Solid > Compost Lagoon management –Lagoon should be large enough to leave a permanent pool to stabilize microbial population –Apply in June through fall »Odors reduced when microbes are most active –Dilute manure with water liberally »2 – 3 parts H 2 O : 1 part manure –Test for salt and NH 3 concentration –Stop lagoon feeding 2 weeks before pumping »Allows bacteria the opportunity to degrade odor Application method –Injection of manure into soil »Most effective at preventing odors –Surface application with incorporation »Must be done immediately after application

25 –If surface applying liquid manure by irrigation make sure to: »Set sprayer for large droplets Reduce droplet surface area »Adequately dilute manure with clean water 2:1 »Monitor wind direction Shut down if wind blows towards neighboring residences »Monitor wind spead Shut down if wind speed exceeds 5 mph Prevents dilution of odor

26 Consideration of neighbors as a method to control manure odor nuisance complaints –Siting of operation and fields for manure application Major tool to limit odor nuisance complaints Considerations –Distance »Odors decreases exponentially with distance »Distances (Required to use the Master Matrix) > Residences >¼ mile from buildings >750 ft from manure application-Surface applied > Residential development >1 mile from buildings >750 ft from manure application-Surface applied –Topography »Don’t build uphill from residences –Prevailing winds »Don’t build so residences are downwind of the prevailing winds Especially during the spring –Building orientation »Short side of livestock facility should be perpendicular to the neighbor’s residence

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30 –Timing of manure application Tell neighbors when you plan to spread manure Select days when wind is blowing away from neighbors Avoid spreading manure on weekends, holidays, or on days when neighbors have a social event planned –Facility maintenance Maintain buildings and grounds around facilities –Mow grass –Control weeds Proper dead animal disposal Avoid spilling manure on roads


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