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Odor/Odorous Gases. Typical livestock odorantsSulfides (H2S)Volatile fatty acids (VFAs)MercaptansAmmonia (NH3)
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1. Workshop Topics Odour Emission Measurement
Swine Odour and Emissions
Poultry Odour and Emissions
Nationwide Emissions Project
2. Odor/Odorous Gases Typical livestock odorants
Sulfides (H2S)
Volatile fatty acids (VFAs)
Mercaptans
Ammonia (NH3) & amines
Alcohols
Aldehydes
Esters
Carbonyls
3. Slides – odor sampling: Mark Spence Claude Diehl Tedlar bagsSlides – odor sampling: Mark Spence Claude Diehl Tedlar bags
4. Bag Sampling
New 10-L Tedlar bags
flushed with N2
checked for odorlessness
Pre-conditioned
Simultaneous with gas measurements Slides – odor sampling: Heber odor sampling from reactorSlides – odor sampling: Heber odor sampling from reactor
5. Odor Sampling Use gas sampling system
Freeze fans during sampling
2-3 replications
Flush and precondition bags
Include background Slides – Odor Sampling: PSF freeze emissions Amy
The gas sampling system is used to collect bag samples from any of the gas sampling locations. The producer is asked to override and manual “freeze” the ventilation rate for 30 min prior to sampling. Odor sampling of 3 replications take 15 minutes followed by a return to automatic fan control. With samples taken at the exhaust and background, building odor emissions are calculated in terms of odor units per second. This emission rate can be used to predict downwind impact, or to compare abatement technologies.Slides – Odor Sampling: PSF freeze emissions Amy
The gas sampling system is used to collect bag samples from any of the gas sampling locations. The producer is asked to override and manual “freeze” the ventilation rate for 30 min prior to sampling. Odor sampling of 3 replications take 15 minutes followed by a return to automatic fan control. With samples taken at the exhaust and background, building odor emissions are calculated in terms of odor units per second. This emission rate can be used to predict downwind impact, or to compare abatement technologies.
6. Odor Measurements Field olfactometer
For evaluating ambient air
Determines odor concentrations with human nose
Six dilution ratios
Dynamic, forced-choice olfactometer
For evaluating source samples
Utilizes human olfactometric senses (4-8 people)
Odor threshold where 50% of panel is correct
Gas chromatography, mass spectrometry (GC-MS)
Separates gases
Measures presence and concentration
Hydrogen sulfide (popular surrogate gas for odor)
Sensor arrays (electronic nose) From Sweeten et al., 2/24/02
Sensory Methods (human noses)—
A. Dilutions to threshold (DT) methods
* Scentometer, 1.5 – 350 DT range.
* Dynamic olfactometer, 8 - 66,667 ODT range
Draft Standards—European (CEN, 1999), U. S. (O’Brien, 1995).
B. Suprathreshold referencing, n-butanol.
Conc. ~1.25 - 80 ppm field measurement
Calibration of panelists & olfactometers
Electronic “noses” —
Links chemical detection with sensory responses.
Developmental.
Complexity of livestock odors.
From Sweeten et al., 2/24/02
Sensory Methods (human noses)—
A. Dilutions to threshold (DT) methods
* Scentometer, 1.5 – 350 DT range.
* Dynamic olfactometer, 8 - 66,667 ODT range
Draft Standards—European (CEN, 1999), U. S. (O’Brien, 1995).
B. Suprathreshold referencing, n-butanol.
Conc. ~1.25 - 80 ppm field measurement
Calibration of panelists & olfactometers
Electronic “noses” —
Links chemical detection with sensory responses.
Developmental.
Complexity of livestock odors.
7. Odor Emission Descriptors 1. Concentration = mass/vol., ?g/m3 ? OU/m3
2. Emission rate = concentration x airflow rate = mass/unit time (kg/day) = OU/sec
3. Flux = mass/unit time/unit area (kg/sec/m2); OU/sec/m2
Example (Smith & Watts, 1994 cited by Sweeten et al., 2002
Dry pad/manure surface: 5 OU/s-m2
Wet pad/manure surface: 100 OU/s-m2
4. Emission factor = emission rate/process descriptor
= mass/unit time/capacity,
= kg/day/head; OU/sec/head. Feedlot Emission Rates (Smith & Watts, 1994):
Dry pad/manure surface = 5 OU/s*sq. m.
Wet pad/manure surface = 100 OU/s*sq. m.
Feedlot Emission Rates (Smith & Watts, 1994):
Dry pad/manure surface = 5 OU/s*sq. m.
Wet pad/manure surface = 100 OU/s*sq. m.
8. Panelist Rules (BMPs): Be free of physical conditions affecting sense of smell (colds, pregnancy, etc.)
Not smoke or use smokeless tobacco
Not eat, drink or chew gun 1 h before session
Not eat spicy food prior to session
Be fragrance free
Not consume alcohol for 3 h prior
Not discuss or comment on odors with others
Keep odor work confidential
Not have been fasting or involved in substance abuse
Arrive at least 5 minutes before session begins.
Panelists must:
1. be free of physical conditions that affect the sense of smell (colds, pregnancy, etc)
2. not smoke or use smokeless tobacco
3. not eat, drink or chew gum the hour before or during the panel session; however, drinking water is allowed
4. not eat spicy food before the panel session
5. be fragrance free (no perfume, cologne, etc. also no scented shampoos, soaps, drier sheets, etc.)
6. not consume alcohol for 3 hours prior to a session
7. not discuss or comment on odors with other panelists
8. keep odor work confidential
9. not have been fasting or involved in substance abuse
10. arrive at least 5 minutes before a session begins.
Panelists must:
1. be free of physical conditions that affect the sense of smell (colds, pregnancy, etc)
2. not smoke or use smokeless tobacco
3. not eat, drink or chew gum the hour before or during the panel session; however, drinking water is allowed
4. not eat spicy food before the panel session
5. be fragrance free (no perfume, cologne, etc. also no scented shampoos, soaps, drier sheets, etc.)
6. not consume alcohol for 3 hours prior to a session
7. not discuss or comment on odors with other panelists
8. keep odor work confidential
9. not have been fasting or involved in substance abuse
10. arrive at least 5 minutes before a session begins.
9. Reference Odorant n-butanol cal gas
C = 40 to 60 ppm
ODCb = 1000 Cb/ODTb
prEN 13725 standard (CEN, 2001)
Panelist performance criteria (n=10):
20 < mean ODCb < 80 ppb
Standard deviation of log ODCb < 2.3
Panel performance criteria (n=10):
31 < mean ODCb < 51 ppb
A < 0.213
R < 0.477
Purdue interim criteria for panelists (n=5)
10 < mean ODCb < 160 ppb
Needed only about two months
10. Results for 57.5 ppm n-butanol reference odor
Assessor Step 1 2 3 4 5 Log D
A 1 1 6 6 8 3.42
A 1 1 6 8 3.42
B 2 1 6 6 8 3.42
B 2 2 1 6 8 3.13
C 1 1 1 6 8 3.13
C 2 5 6 6 8 3.42
D 1 1 2 6 8 3.13
D 1 1 6 8 3.42
E 1 1 1 6 8 3.13
E 2 1 1 8 8 3.13
Final Results:
Response Key: D
1 = Incorrect Guess Avg. Log Value 3.19
2 = Correct Guess
5 = Incorrect Detection Dilutions to threshold 1,544
6 = Correct Detection
8 = Correct Recognition
Odor detection concentration = 57,500 ppb / 1,544 = 37 ppb
compared to CEN requirements of 20 to 80 ppb
11. Study Ratings (Watts,1999) 5: prEN 13725 olfactometry
4: NVN2820 olfactometry, report ODCb
3: Nonstandard olfactometry, no ODCb
2: Scentometer
1: Casual sniffing
12. Repeatability
13. Accuracy
15. n-butanol vs. Hydrogen Sulfide
16. Conclusions prEN 13725 for accuracy and repeatability with n-butanol have been achieved and maintained
Hydrogen sulfide correlated with n-butanol
17. Odor Intensity Relative perceived psychological strength of odor
Suprathreshold levels only (>ODT)
Static Odor Intensity Referencing Scale (n-b in water)
Five concentrations of n-butanol with 3X progression
Often used by field odor inspectors
Objectively match intensities
18. Persistence of Odor From Sweeten et al., 2/24/02
Odor Unit, OU
Amount of odorant in 1 cu. m. of odor-free air at ODT.
Numerical equivalency—>ODT, DT, OU, OU/cu.m.
Odor Intensity (I), (Stevens, 1961)
“Stevens Law”
I = k C **( Exp n)
Where C = concentration, ppm, ppb, OU, OU/m**3
Example: Swine nurseries (2), Purdue
I = 3.67 C **0.977
From Sweeten et al., 2/24/02
Odor Unit, OU
Amount of odorant in 1 cu. m. of odor-free air at ODT.
Numerical equivalency—>ODT, DT, OU, OU/cu.m.
Odor Intensity (I), (Stevens, 1961)
“Stevens Law”
I = k C **( Exp n)
Where C = concentration, ppm, ppb, OU, OU/m**3
Example: Swine nurseries (2), Purdue
I = 3.67 C **0.977
19. Persistence of Nursery Pig Odor
20. Hedonic Tone Degree to which an odor is subjectively perceived as pleasant or unpleasant
Perceptions vary widely among people
An emotional reaction
Personal odor preference
Individual odor experience
Purdue: -10 (extremely unpleasant) to 0 (neither) to +10 (extremely pleasant)
VDI 3882 proposed a –4 to +4 scale.
Slides – odor measurement: Hedonic Tone
Slides – odor measurement: Hedonic Tone
21. VDI 3882Determination of Hedonic Tone Conclusive assessment about odor nuisance not possible with DT alone.
Determine intensity and HT separately.
Polarity profiles of panelists, e.g. strong vs. weak, soft vs. hard, mild vs severe, etc. for words and chemicals.
Six suprathreshold concentrations starting with panel threshold, or to only undiluted test sample.
Random presentations
Calculate Hc and Hs to represent sample.
Behavior curve of hedonic odor tone:
Assume acceptable hedonic odor tone.
Determine reduction % needed if inlet odor ht behavior is known.
If cleaning process changes composition, then tests must be done on outlet air.
HT behavior curves allow prediction of ht in the immission zone.
Changed hedonic tone must be taken into account with abatement technologies.
Vanillin in dipropylene glycol should result in +2.9 to +1.9.
Guaiacol in water should result in –0.8 to –2.0.
22. Behavior Curve of H.T. (VDI 3882)
23. “HT Behavior Curve” of Nursery Odor
24. Odor Character Descriptors
25. Adjectives of Odor Descriptors Burnt, chopped, cooked, decayed, dry, fermented, foul, fresh, new, old
Rancid, raw, rotten, scorched, shredded, stale, wet
26. Odor Evaluations of Corn Wet Mill
27. Swine House Odors and Emissions
28. Nursery Odor
29. Swine Lagoon Odor
30. Daily Ammonia Emission Rates, g/d-AU
31. Hydrogen Sulfide Concentrations
32. Hydrogen Sulfide Concentrations
33. Diurnal H2S Concentration
34. Ambient Hydrogen SulfideNear 12,000-Pig Nursery-Finishing Site Slides – ambient h2s data: MAPA at Valadco dataSlides – ambient h2s data: MAPA at Valadco data
35. Hydrogen Sulfide vs. OdorSwine Buildings
36. Hydrogen Sulfide vs. Odor(Swine Lagoon)
37. The burst of hydrogen sulfide during flushing with lagoon effluent is newly discovered since there appears to be no similar data reported in the literature. According to the Occupational Safety and Health Administration (OSHA), the permissible exposure levels (PEL) are 20 ppm ceiling for 10 minutes for general industries, respectively (OSHA, 2001b). Although the 8-h average would be relatively unaffected by the brief increase, it should be noted that greater H2S release may occur from other lagoon recycling systems. The lagoon used in this study was properly sized and recognized for its low odor emission rate. The burst of hydrogen sulfide during flushing with lagoon effluent is newly discovered since there appears to be no similar data reported in the literature. According to the Occupational Safety and Health Administration (OSHA), the permissible exposure levels (PEL) are 20 ppm ceiling for 10 minutes for general industries, respectively (OSHA, 2001b). Although the 8-h average would be relatively unaffected by the brief increase, it should be noted that greater H2S release may occur from other lagoon recycling systems. The lagoon used in this study was properly sized and recognized for its low odor emission rate.
38. Daily Mean Pit Exhaust Concentration ¦=NH3
?=H2S Discuss and compare the effects of storage time, the cycles, and burst of H2S conc. during flushing, etcDiscuss and compare the effects of storage time, the cycles, and burst of H2S conc. during flushing, etc
39. The exhaust temperature was held at about 20 C except on two of the warmest days.The exhaust temperature was held at about 20 C except on two of the warmest days.
40. National Livestock Consent Agreement and Air Emissions Study The purpose of this research project is to provide quality-assured air emission data from representative swine farms in the U.S., to U.S. EPA, in the effort to determine which farms might fall under regulatory authority. Following sound scientific principles, this project will collect new data and aggregate existing emissions data from previous studies. These data will serve as the beginning of a database to which new data can be added as emissions and against which control technologies can be compared.
Objectives:
Determine whether individual swine farms are likely to emit particulate matter (both total suspended particulate [TSP], particles smaller than 10 and 2.5 microns [PM10 & PM2.5]), and volatile organic compounds (VOC) in excess of applicable Clean Air Act (CAA) thresholds.
Determine whether individual swine farms are likely to emit ammonia (NH3) and hydrogen sulfide (H2S) in excess of applicable Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) reporting requirements.
By John Thorne
C&M Capitolink
Agri-Business Research Council
By John Thorne
C&M Capitolink
Agri-Business Research Council
41. Vulnerability for Past Emissions Odor complaints are driving air enforcement
Emissions enforcement is new to agriculture
Lawsuits often result in
heavy penalties
expensive legal & consultant fees
emissions monitoring
control requirements
management interruption – expensive even if you win
Here’s the rub: vulnerability for past violations
42. Real-Time Emission Data to be Collected by PELFCA
Ammonia – chemiluminescence
NOx - chemiluminescence
Hydrogen sulfide – Pulsed-Fluorescence
Carbon dioxide – Photoacoustic Infrared
FTIR for ammonia and some VOC
UV for ammonia and hydrogen sulfide
PM10 – (TEOM)
PM2.5 – Partisol dichomotous sampler
VOC: GC-MS (32 samples per site)
TSP: integrated samples with Illinois method.
Building airflow (fan status, pressure, vane anemometer, FANS)
Include ambient measurements of PM, gases
Real-time emission data.Real-time emission data.
43. Operational Data to be Collected by PELFCA
Heating, flushing, feeder, and fan operation
Temperature and humidity
Building static pressure
Animal activity
Lighting
Wind speed and direction
Solar radiation
Animal inventory and mass
Manure production
Manure removals
Manure, feed and water analysis
Milk production
Egg production List of operational data.List of operational data.
44. Details of the gas sampling system are very important to proper gas emission measurements. The heart of the gas sampling system is the pump. This pump takes air and blows it through a manifold. The disadvantage with this is that the sample passes through the pump before being analyzed, however, we use Teflon lined diaphragms in the pump. The advantages of pushing air through the manifold are several but the main advantage is that the analyzer pumps do not have to compete with the main sampling pump. The analyzer manifold M3 is Teflon and is at a pressure slightly above atmospheric. Analyzers will draw subsamples out of M3.
The pump P2 draws air from a Teflon probe manifold to which we can connect multiple probes. At Purdue, we’ve connected 3 to 40 probes to a manifold like this. We connect 12 probes in the APECAB study.
Each probe has a 3-way Teflon solenoid controlled by a computerized data acquisition system so that we can sequence each line one by one into the analyzer manifold M3 for real-time analysis.
The sampling probe which consists of a Teflon filter holder and membrane filter to protect the system from dust particles, water droplets, and insects. Teflon tubes (10 to 115 m long) connect the sampling probe and the 3-way solenoid.
So we can see that sample air flows through the filter in the barn through 10 to 115 m long Teflon tubes, then through a 3-way solenoid into a Teflon probe manifold, from which a sampling pump draws from and pushes the air through the Teflon analyzer manifold M3.
The ammonia analyzers, with its own external vacuum pump, draws air from this manifold. We put a filter there to protect the analyzer from any dust particles that might enter our gas sampling system. This ammonia analyzer measures 5 to 150 ppm in barn air as compared with sub-ppm in most ambient monitoring application. We also are introducing this external gas sampling system. I say external because the analyzer itself has a similar gas sampling system inside it which I refer to as the internal gas sampling system.
Since the tubes are long, a bypass pumping circuit is used to reduce the time for system response between samples. With 12 locations, one line is always sampled and 11 lines flow through manifold M1.
Several innovations were introduced to this system at Purdue University during an EPA-funded methods development project last year. First, we introduced a bag filling port so that odor and gas samples could be collected inside the trailer. Comparison studies at Purdue and ISU confirmed the validity of this method.
Next, we installed a mass flow meter so we could monitor the sampling flow rate. This is very important. If there is one variable that I would want to have pop up on my laptop in a little window right now is the sampling flow rate to let me know that the pump is working properly. This was not sensitive enough for us to detect slight leaks in sampling probes.
Then we installed a pressure sensor and the APECAB partners all agree that this is a huge troubleshooting tool because it is very sensitive to leaks and plugging of lines and we’ve detected both in our studies.
A leak test circuit is used to test for leaks in the external gas sampling system. This is done every week or two weeks.
The beauty of this GSS is that additional analyzers can be easily added to the system. Therefore, we have a hydrogen sulfide analyzer also drawing a subsample from the main sample flow.
We use standard gases in compressed gas cylinders to calibrate the analyzers. The gas is introduced into an auxiliary calibration manifold M4. This is a manual method where we have to remove the analyzer inlet tubing from M3 and connect it to M4 during calibration. One by one, we connect a different gas cylinder to M4 as we go through the calibration process.
This system that you see here is the base system used in the APECAB project. All the units for the APECAB project were constructed and tested at Purdue University, and delivered to the other states involved in the project (MN, IA, TX, IL, NC). A cost savings of about $2K per GSS was realized by quantity discounts on parts and efficiencies of mass production.
Our lab at Purdue have done several things to improve
In Missouri, the calibration circuit includes a programmable diluter, a programmable solenoid manifold, and calibration tubes that deliver known concentrations to the probes, to the probe manifold or to the analyzer manifold. Leak tests are regularly conducted.Details of the gas sampling system are very important to proper gas emission measurements. The heart of the gas sampling system is the pump. This pump takes air and blows it through a manifold. The disadvantage with this is that the sample passes through the pump before being analyzed, however, we use Teflon lined diaphragms in the pump. The advantages of pushing air through the manifold are several but the main advantage is that the analyzer pumps do not have to compete with the main sampling pump. The analyzer manifold M3 is Teflon and is at a pressure slightly above atmospheric. Analyzers will draw subsamples out of M3.
The pump P2 draws air from a Teflon probe manifold to which we can connect multiple probes. At Purdue, we’ve connected 3 to 40 probes to a manifold like this. We connect 12 probes in the APECAB study.
Each probe has a 3-way Teflon solenoid controlled by a computerized data acquisition system so that we can sequence each line one by one into the analyzer manifold M3 for real-time analysis.
The sampling probe which consists of a Teflon filter holder and membrane filter to protect the system from dust particles, water droplets, and insects. Teflon tubes (10 to 115 m long) connect the sampling probe and the 3-way solenoid.
So we can see that sample air flows through the filter in the barn through 10 to 115 m long Teflon tubes, then through a 3-way solenoid into a Teflon probe manifold, from which a sampling pump draws from and pushes the air through the Teflon analyzer manifold M3.
The ammonia analyzers, with its own external vacuum pump, draws air from this manifold. We put a filter there to protect the analyzer from any dust particles that might enter our gas sampling system. This ammonia analyzer measures 5 to 150 ppm in barn air as compared with sub-ppm in most ambient monitoring application. We also are introducing this external gas sampling system. I say external because the analyzer itself has a similar gas sampling system inside it which I refer to as the internal gas sampling system.
Since the tubes are long, a bypass pumping circuit is used to reduce the time for system response between samples. With 12 locations, one line is always sampled and 11 lines flow through manifold M1.
Several innovations were introduced to this system at Purdue University during an EPA-funded methods development project last year. First, we introduced a bag filling port so that odor and gas samples could be collected inside the trailer. Comparison studies at Purdue and ISU confirmed the validity of this method.
Next, we installed a mass flow meter so we could monitor the sampling flow rate. This is very important. If there is one variable that I would want to have pop up on my laptop in a little window right now is the sampling flow rate to let me know that the pump is working properly. This was not sensitive enough for us to detect slight leaks in sampling probes.
Then we installed a pressure sensor and the APECAB partners all agree that this is a huge troubleshooting tool because it is very sensitive to leaks and plugging of lines and we’ve detected both in our studies.
A leak test circuit is used to test for leaks in the external gas sampling system. This is done every week or two weeks.
The beauty of this GSS is that additional analyzers can be easily added to the system. Therefore, we have a hydrogen sulfide analyzer also drawing a subsample from the main sample flow.
We use standard gases in compressed gas cylinders to calibrate the analyzers. The gas is introduced into an auxiliary calibration manifold M4. This is a manual method where we have to remove the analyzer inlet tubing from M3 and connect it to M4 during calibration. One by one, we connect a different gas cylinder to M4 as we go through the calibration process.
This system that you see here is the base system used in the APECAB project. All the units for the APECAB project were constructed and tested at Purdue University, and delivered to the other states involved in the project (MN, IA, TX, IL, NC). A cost savings of about $2K per GSS was realized by quantity discounts on parts and efficiencies of mass production.
Our lab at Purdue have done several things to improve
In Missouri, the calibration circuit includes a programmable diluter, a programmable solenoid manifold, and calibration tubes that deliver known concentrations to the probes, to the probe manifold or to the analyzer manifold. Leak tests are regularly conducted.