Larry D. Jacobson

Continuous monitoring of ammonia, hydrogen sulfide and dust emissions from swine, dairy and poultry barns

Three naturally ventilated animal buildings (swine, dairy, and turkey) were monitored ncontinuously for a 10-day period during the summer and a 10-day period in the winter of 2001 for nhydrogen sulfide and ammonia. Grab samples of dust and odor were also made during these nmonitoring periods. Emissions of ammonia were similar to that found in European literature. nSignificant variations were found between winter and summer emissions on the turkey barn. nAmmonia emissions did not increase with increasing building ventilation rate.

Evaluation of OFFSET (Odor Setback Model) Using Neighborhood Monitors

A comparison between observed and predicted odor intensities at neighbors living in the nvicinity of various livestock farms in 5 different Minnesota counties was made to evaluate an odor nsetback tool developed by the University of Minnesota. In 309 out of 570 reported odor events the nfarms participating in the investigation were the probable odor sources. In 199 (64%) of these an nodor less than intensity 2 was predicted but an odor intensity equal to 2 or above was reported. In 99 ncases (32%) the predicted and reported odor intensity was in agreement, being either higher than 2 nor below 2. Regarding all observations the observed odor intensity was significantly higher than the npredicted. Possible reasons for these mixed results are; variations in odor rating and sensitivity of nresident recorders, wind speed fluctuations, possible errors and fluctuations in odor emissions from neach farm (only one emission measurements were made at each farm), topographic variation nbetween sites since OFFSET assumes flat surfaces, and background emissions from other sources nthat may have contributed to what resident recorders were smelling.

A Two-Year Study of the Effectiveness of Geotextile Covers to Reduce Odor and Gas Emissions from Manure Storages

Odor, hydrogen sulfide (H2S), ammonia (NH3) and volatile organic compounds (VOC) were measured nbetween May and October 2000, and between April and October 2001 at three sites in Southwest Minnesota. Each nsite consisted of a pair of farms (nursery N1A, N1B; 2,000-head finishing F2A, F2B; 3,000-head finishing F3A, F3B). nA manure storage from each pair was selected as treatment, where a geotextile cover (BioCap .) was installed. nResults showed that there was a significant deterioration of the performance of geotextile covers in reducing odor and ngas emissions from manure storages on the second year of the study. Odor emissions were, in average, reduced by n48% over the two-year period. Emission rates were reduced by 90% in terms of H2S in the first year, but no nsignificant differences were found between covered and non-covered manure storages in 2001. NH3 emissions were, nin average, reduced by 44% in 2001. No significant differences in total-VOC emissions from covered and noncovered nmanure storages were observed during the two-year study. Analysis of the ambient H2S data suggested that nthe covers were effective in reducing ambient H2S concentrations near manure storages located at the two finishing nsites. Odor and gaseous emission rates from all sites were poorly correlated with most manure characteristic nparameters (nutrients, solids, organic matter, VOCs).

Odor and gas emissions from a naturally crusted swine manure storage

Odor, hydrogen sulfide, ammonia and volatile organic compounds were measured nover a period of five months at two swine manure storages in the summer of 2000. One of the nstorages developed a natural crust. Results showed that the natural crust seems to be able to nsignificantly reduce H2S emissions from swine manure storages. The natural crust also helped nreduce odor, NH3, and other VOC emissions from the manure storage, but reductions were not nstatistically significant. The effect of the natural crust was to cause an increase on the nconcentration of most parameters in manure. The natural crust seems to be particularly effective nin trapping sulfide compounds.

ODOR AND HYDROGEN SULFIDE EMISSION FROM A DAIRY MANURE STORAGE

Ambient H2S air concentrations were measured continuously for a period of approximately 30days around a manure storage basin at a 700-dairy cow operation in Minnesota. Manure wasagitated and pumped from the basin during the first week of monitoring. Odor samples were takenon two different occasions during the monitoring period using a wind tunnel placed just above themanure basin surface. Odor plume measurements were also made, but on a single day only. Barn emissions did not seem to contribute much to hydrogen sulfide concentrations measuredaround the manure storage. This was verified by sorting the H2S measurements obtained whenwind was blowing from the barn toward the manure storage for the two monitors located at thesouth side of the basin. Mean H2S concentrations downwind of the barn were between 0.02 and5.7 ppb, while mean H2S concentrations around the storage varied between 0.9 and 20 ppb. A limited number of odor samples taken during the monitoring period suggested that the manurestorage contributed significantly to odor emission as compared to the barn. Emission from thestorage was between 7 and 10 OU/m2-s, while emission from the barn was between 2 and 3OU/m2-s. Odor plume measurements taken at 60 and 120 m downwind from the barn indicated adecrease of 10 OU per 60 m.

Design and Management of an Oil Sprinkling System to Control Dust, Odor, and Gases in and from a Curtain-Sided Pig Finishing Barn

The oil/water sprinkling system has been evaluated for reduction of odor emissions from ndeep-pitted, curtain-sided pig finishing buildings. The oil was sprinkled in barns at the average rate of 6.7 nmL/m 2 /day to reduce dust as recommended in MWPS AED-42 (Zhang et al., 1997). The reduction in odor nemission was assessed by measurements of odor concentrations in air samples collected from barns and nair exhausts. In addition, the H2S (hydrogen sulfide) and NH3 (ammonia) concentrations and emissions nwere measured. The reduction of odor, H2S and NH3 concentrations in rooms treated with oil were nstatistically significant (p-value<0.05) compared to control rooms at one farm location. There was no nstatistically significant reduction observed between oil treatment and control rooms at the second farm nlocation. Using recommended oil application rates for dust control the sprinkling system provided a total ndust mass concentration reduction of 59% compared to control rooms. The respirable and inhalable dust nparticle concentrations were reduced by 65% and 79 %, respectively.

Hydrogen Sulfide Dispersion, Summary of Model Farms

AERMOD and CALPUFF were used to predict ambient concentrations near a 2000 head nfinishing site in three locations in Minnesota over five consecutive years. Results indicate that npredicted property line setback distances using AERMOD are greater than those distances predicted nby CALPUFF. There was also variability between geographic locations, between years, monthly, and ndiurnally. Results of the evaluation of this data suggest that setback predictions using AERMOD or nCALPUFF will yield different results and that these differences are likely significant to the livestock nindustry.

Comparison of Ambient Odor Assessment Techniques in a Controlled Environment

This paper compares results of using - dynamic triangular forced-choice olfactometry (DTFCO), Mask Scentometers, Nasal Rangers®, and an odor intensity reference scale (OIRS) –intensity ratings - to assess odors in a controlled-environment chamber in the Iowa State University Air Dispersion Laboratory. The methods were used to assess thirteen odor levels in the chamber where swine manure mixed with water was used to vary the odor levels. Dynamic triangular forced-choice olfactometry did not correlate well to the other ambient odor assessment methods. Predicting D/T using intensity ratings degraded Ro2 with the other methods in all cases. Average Intensity-predicted D/T, the Mask Scentometer and the Nasal Ranger® correlated well with each other, had strong Ro2 (greater than 0.85), had regression slopes nearest one, and the session means were not found to be significantly different (a=0.05). Using the geometric means of the device D/T settings, (D/T)G, improved Ro2 between the other methods and the Nasal Ranger® and Mask Scentometer. Average Intensity-predicted D/T values were three to four times higher than Nasal Ranger® assessment ((D/T)G and D/T, respectively), and a Nasal Ranger® (D/T)G was roughly five times higher than Mask Scentometer (D/T)G.

Ground Truthing CALPUFF and AERMOD for Odor Dispersion from Swine Barns using Ambient Odor Assessment Techniques

A collaborative research effort by several institutions investigated the dispersion of odors from a swine production facility. Trained human receptors measured downwind odor concentrations from four tunnel-ventilated swine finishing barns near Story City, Iowa, during twenty measurement events conducted between June and November 2004. Odor concentrations were modeled for short time steps using CALPUFF and AERMOD atmospheric dispersion models to compare predicted and measured odor levels. Source emission measurements and extensive micrometeorological data were collected along with ambient odor measurements using the Nasal Ranger® device (St. Croix Sensory, St. Paul MN), Mask Scentometer, odor intensity ratings, and air sample analysis by dynamic triangular forced-choice olfactometry (DTFCO). AERMOD predictions fit the odor measurements slightly better than CALPUFF with predicted concentrations being about half those predicted by CALPUFF. The Mask Scentometer and Nasal Ranger® measurements related best to the dispersion model output, and scaling factors of 3.0 for CALPUFF and 2.4 for AERMOD suggested for the Nasal Ranger® and 0.5 for the Mask Scentometer (both models). Measurements obtained using the Nasal Ranger®, Mask Scentometer, and odor intensity ratings correlated well to each other, had the strongest linear relationships, and provided slopes (measured: modeled) closest to 1.0. Converting intensity ratings to a dilution to threshold concentration did not correlate and relate as well, and this method was deemed less desirable for ambient odor assessment. Collection of ambient air samples for analysis in a olfactometry laboratory displayed poor correlations with other methods and should not be used to assess ambient odors.

ODOR MITIGATION FOR CONCENTRATED ANIMAL FEEDING OPERATIONS: WHITE PAPER AND RECOMMENDATION

Current Status nOdor from Concentrated Animal Feeding Operations (CAFOs) n• CAFOs affect air quality through emissions of odor, specific odorous gases (odorants), odorcarrying nparticulates (including organic, inorganic, and biological particulate matter), and nvolatile organic compounds (VOCs). n• Odor from CAFO sources, as experienced by humans, is the composite of 170 or more specific ngases in trace concentrations. n• Odorous gases of primary concern often include hydrogen sulfide (H2S) and VOCs, including nvolatile fatty acids. n• Odor research in the field and laboratory has largely focused on measuring concentrations in nterms of dilutions to threshold (odor units per cubic meter) and odor intensity based on category nor reference scaling. nEmission Characteristics n• Data on odor/odorant emission rates, flux, and emission factors are seriously lacking. n• Systematic efforts have not yet been initiated to develop accurate emission factors for odorous ngases (VOCs, H2S, etc.) that properly represent CAFOs in the U.S. and are needed to develop nscience-based permitting and abatement policies. nHuman Response n• Odor from CAFOs can cause physiological or psychological health responses with regard to n(a) frequently exposed neighbors at high concentrations, and (b) certain people with particular nsensitivities for whom the health effects are of greater concern. nCurrent Federal and State Policies n• Federal and State policies regarding CAFOs primarily have addressed water quality protection nfrom point sources under the Federal Clean Water Act and equivalent state statutes; however, nonly in a few cases have these policies addressed odor and odorants. nIntegrated Mitigation Programs n• Approaches to control odor and odorants include: ration/diet modification, manure treatment, ncapture/treatment of emitted gases, and enhanced dispersion. Each of these mitigation approaches nincludes several specific technologies. n• A particular CAFO may require implementation of one, two or more approaches in order to nmeet the environmental quality demands of the area in which it is located.