Brent Dahl Swine Feedlot Project Environmental Assessment ... · Brent Dahl is proposing to construct two 2,400-head hog total confinement finishing barns (Project) in the SE¼ of

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Alternative EAW Form for Animal Feedlots

ENVIRONMENTAL ASSESSMENT WORKSHEET

Note to reviewers: The Environmental Assessment Worksheet (EAW) provides information about a project that may have the potential for significant environmental effects. This EAW was prepared by the Minnesota Pollution Control Agency (MPCA), acting as the Responsible Governmental Unit (RGU), to determine whether an Environmental Impact Statement (EIS) should be prepared. The project proposer supplied reasonably accessible data for, but did not complete the final worksheet. Comments on the EAW must be submitted to the MPCA during the 30-day comment period which begins with notice of the availability of the EAW in the Minnesota Environmental Quality Board (EQB) Monitor. Comments on the EAW should address the accuracy and completeness of information, potential impacts that are reasonably expected to occur that warrant further investigation, and the need for an EIS. A copy of the EAW may be obtained from the MPCA by calling 651-297-8510. An electronic version of the completed EAW is available at the MPCA Web site http://www.pca.state.mn.us/news/eaw/index.html#open-eaw. 1. Basic Project Information.

A. Feedlot Name: Brent Dahl Swine Feedlot Project B.

Feedlot Proposer:

Brent Dahl

C.

RGU:

Minnesota Pollution Control Agency

Technical

Contact Person Jared Anez

Contact Person

Kevin J. Kain

and

Title President, Anez Consulting, Inc.

and Title

Project Manager

Address 1025 19th Avenue Southwest Address 520 Lafayette Road North Willmar, Minnesota 56201 St. Paul, Minnesota 55155-4194 Phone (320) 235-1970 Phone 651-296-7432 Fax (320) 235-1986 Fax 651-297-2343 E-mail [email protected] E-mail [email protected]

D. Reason for EAW Preparation: (check one)

EIS Scoping

Mandatory EAW

X

Citizen Petition

RGU Discretion

Proposer Volunteered

If EAW or EIS is mandatory give EQB rule category

subpart number and name: Minn. R. 4410.4300, subp. 29 (A) Animal Feedlots

E. Project Location: County Lac Qui Parle Twp Cerro Gordo SE 1/4 SW 1/4 Section 13 Township 118N Range 43W Watershed (name and 4-digit code):

24025

Lac Qui Parle River Watershed

http://www.pca.state.mn.us/news/eaw/index.html#open-eaw

mailto:[email protected]

mailto:[email protected]

Brent Dahl Swine Feedlot Project Environmental Assessment Cerro Gordo Township, Minnesota 2 Worksheet

F. Attach each of the following to the EAW:

Exhibit 1. State Map showing general location Exhibit 2. County map showing the general location of the project Exhibit 3. U.S. Geological Survey (USGS) 7.5 minute, 1:24,000 scale map indicating project

boundaries Exhibit 4. Map showing one-mile buffer around barn site and manure application sites Exhibit 5. Site plan showing all significant project and natural features Exhibit 6. List of residences near manure application areas Exhibit 7. Four soil maps of manure application areas each followed by list of soil types

(eight pages total) Exhibit 8. Letter from Minnesota Department of Natural Resources (DNR), Natural Heritage

Program (four pages)

Exhibit 9. E-mail from the Minnesota Department of Health, Source Water Protection Unit Exhibit 10. E-mail from the Minnesota Historical Society (2 pages) Exhibit 11. Air Quality Modeling Report for the Brent Dahl Hog Feedlot The National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) Permit Application and associated documents, including the Air Emission and Odor Management Plan, the Animal Mortality Plan, the Emergency Response Plan, and the Manure Management Plan (MMP) are available for review by contacting Mr. George Schwint, of the MPCA’s Willmar office, at 320-214-3793.

G. Project summary of 50 words or less to be published in the EQB Monitor.

Brent Dahl is proposing to construct two 2,400-head hog total confinement finishing barns (Project) in the SE¼ of the SW¼ of Section 13 of Cerro Gordo Township, Lac Qui Parle County. Manure will be collected in an eight-foot-deep concrete pit beneath each barn. Manure will be removed from the pits once per year in the fall after the crops have been harvested and injected at agronomic rates into designated cropland as fertilizer. The total number of animal at the proposed site is 4,800 or 1,440 animal units (AUs).

H. Please check all boxes that apply and fill in requested data:

Animal Type Number Proposed Type of Confinement Finishing hogs 4,800 (1,440 AUs ) Total Confinement Sows Nursery pigs Dairy cows Beef cattle Turkeys Layer hens Chickens Pullets Other (Please identify species)


I. Project magnitude data.

Total acreage of farm: Approximately five acres at the barn site and 1,124

adjacent acres under land application agreement Number of AUs proposed in this project: 1,440 Total AU capacity at this location after project construction: 1,440 Acreage required for manure application: 996

J. Describe construction methods and timing.

Brent Dahl plans to begin dirt work in the spring of 2007, assuming all applicable permits have been issued. Each total confinement barn will be 196-foot by 102-foot with concrete slat floors and metal gating with an 8-foot deep manure storage pit. The manure storage areas will be constructed using reinforced concrete to the specifications of a licensed professional engineer. The manure storage areas will have pit ventilation. The animal holding areas will be constructed for tunnel ventilation.

K. Past and future stages. Is this Project an expansion or addition to an existing feedlot? Yes No Are future expansions of this feedlot planned or likely? Yes No If either question is answered yes, briefly describe the existing feedlot (species, number of

animals and AUs, and type of operation) and any past environmental review or the anticipated expansion. There are no expansion plans for this site at this time.

2. Land uses and noteworthy resources in proximity to the site. A. Adjacent land uses. Describe the uses of adjacent lands and give the distances and directions to

nearby residences, schools, daycare facilities, senior citizen housing, places of worship, and other places accessible to the public (including roads) within one mile of the feedlot and within or adjacent to the boundaries of the manure application sites. Land surrounding the site is zoned and utilized for agriculture. There is a residence adjacent to the Project site, which is owned by a relative of the Project proposer. Other residences adjacent to the proposed site: North - one neighbor 3,874 feet and one neighbor 5,248 feet East - one neighbor 4,601 feet Southeast – one neighbor 3,364 feet Southwest – one neighbor 4,509 feet and one neighbor 5,252 feet There are 11 additional residences located within the manure application areas, as listed in Exhibit 6.

County Road 62 is directly south of the site, a township road is approximately ¼-mile directly west of the site, and County Road 73 is approximately ¾-mile to the east of the site.


The manure application sites are adjacent to State Highway 40, County State Aid Highways 20, 24, 25, and 26, and the previously-mentioned County Roads 62 and 73.

B. Compatibility with plans and land use regulations. Is the project subject to any of the following

adopted plans or ordinances? Check all that apply:

local comprehensive plan land use plan or ordinance shoreland zoning ordinance flood plain ordinance wild or scenic river land use district ordinance local wellhead protection plan

Is there anything about the proposed feedlot that is not consistent with any provision of any ordinance or plan checked? Yes No. If yes, describe the inconsistency and how it will be resolved. Are there any lands in proximity to the feedlot that are officially planned for or zoned for future uses that might be incompatible with a feedlot (such as residential development)? Yes No If yes, describe the potentially affected use and its location relative to the feedlot, its anticipated development schedule, and any plans to avoid or minimize potential conflicts with the feedlot.

C. Nearby resources. Are any of the following resources on or in proximity to the feedlot, manure storage areas, or within or adjacent to the boundaries of the manure application sites?

• Drinking Water Supply Management Areas designated by the Minnesota Department of

Health? Yes No • Public water supply wells (within two miles)? Yes No • Archaeological, historical or architectural resources? Yes No • Designated public parks, recreation areas or trails? Yes No • Lakes or Wildlife Management Areas? Yes No • State-listed (endangered, threatened or special concern) species, rare plant communities or

other sensitive ecological resources such as native prairie habitat, colonial waterbird nesting colonies or regionally rare plant communities? Yes No

• Scenic views and vistas? Yes No • Other unique resources? Yes No If yes, describe the resource and identify any project-related impacts on the resource. Describe any measures to minimize or avoid adverse impacts. Lac Qui Parle River and Minnesota River The Lac Qui Parle River is approximately 1-¾ miles southeast of the site and flows through in one of the manure application sites, and approximately 1/8-mile from two other application sites. The Minnesota River with Lac Qui Parle State Park and Lac Qui Parle Lake is approximately 4 miles east of the Project site, with small portions of the Lac Qui Parle State Wildlife Management Area being approximately ¾-mile from a small part of the manure application area.

A search of the DNR Natural Heritage Database revealed the following rare plant or animal species or other significant natural features are within an approximate one-mile radius of the Brent Dahl site and/or corresponding manure application areas:


• Ammodramus henslowii (Henslow’s Sparrow) • Dry Hill Prairie (Southern) • Limosa fedoa (Marbled Godwit) • Mesic Prairie (Southern) • Wet Prairie (Southern) • Asio flammeus (Short-eared Owl) • Heterodon nasicus (Western Hognose Snake) • Lanius ludovicianus (Loggerhead Shrike) • Speotyto cunicularia (Burrowing Owl)

However, the Endangered Species Environmental Review Coordinator for the DNR stated in her letter that, “based on the nature and location of the proposed project I do not believe it will affect any known occurrences of rare features.” Copies of the DNR Natural Heritage Database, the Minnesota Department of Health, and the Minnesota Historical Society Archeological Review correspondences are found in Exhibits 8, 9, and 10.

3. Geologic and soil conditions.

A. Approximate depth (in feet) to: Feedlot Manure Storage Area Manure Application Sites Ground Water (minimum) 0 0 0 (average) 4 4 4 Bedrock (minimum) >200 >200 >200 (average) >200 >200 >200

B. NRCS Soil Feedlot Manure Storage Area Manure Application Sites Classifications (if known) 137 Dovray

Silty Clay 137- Dovray Silty Clay Various soil type typical of

agricultural land in the area Soil types listed in an exhibit See Exhibit 7

C. Indicate with a yes or no whether any of the following geologic site hazards to ground water are

present at the feedlot, manure storage area, or manure application sites.

Feedlot Manure Storage Area Manure Application Sites Karst features (sinkhole, cave, resurgent spring, disappearing spring, karst window, blind valley, or dry valley)

No No No

Exposed bedrock; No No No Soils developed in bedrock (as shown on soils maps)

No No No

For items answered yes (in C), describe the features, show them on a map, and discuss proposed design and mitigation measures to avoid or minimize potential impacts.


4. Water Use, Tiling and Drainage, and Physical Alterations.

A. Will the project involve installation or abandonment of any water wells, appropriation of any ground or surface water (including dewatering), or connection to any public water supply?

Yes No If yes, as applicable, give location and purpose of any new wells; the source, duration, quantity

and purpose of any appropriations or public supply connections; and unique well numbers and the DNR appropriation permit numbers, if available. Identify any existing and new wells on the site map. If there are no wells known on-site, explain methodology used to determine that none are present. The Project will include the installation of a new well, which will be installed by a licensed well driller. The total estimated water use of the Project at full production will be approximately 4.82 million gallons per year. A DNR Water Appropriations Permit will be required. The purpose of the DNR permit program is to ensure water resources are managed so that adequate supply is provided to long-range seasonal requirements for domestic, agricultural, fish and wildlife, recreational, power, navigational, and quality control. The permit program balances competing management objectives, including both the development and protection of water resources. Minn. Stat. § 103G.261 establishes domestic water use as the highest priority of the state’s water when supplies are limited. If a well interference arises, the DNR has a standard procedure for investigating the matter. If a commercial operator is found to be causing the problem, the operator must correct it. The DNR has indicated to the MPCA staff that it does not foresee any problems related to permitting the volumes of water to be appropriated at this site in relation to the water appropriation in the area. Based on the DNR’s comments, the MPCA staff believes that the water supply for the proposed Project will be adequate, and that the appropriation will not have a significant cumulative effect on the area water supply.

B. Will the project involve installation of drain tiling, tile inlets or outlets? Yes No If yes, describe.

Drain tiles will be installed around the base of each of the manure storage pits. These perimeter tiles are used to control the potential hydrostatic pressure that could be exerted on the pits walls and floors. Inspection ports connected to the perimeter tiles will allow the producer to observe whether or not the tiles are operational, and may help to identify seepage from the pits if a leak were to occur. The inspection ports will consist of covered, 12-inch riser pipes. The perimeter tiles will flow to the south and east of the buildings onto cropland adjacent to the facility. There is approximately 1,000 feet of cropland to the road ditch located to the south. The MPCA has reviewed the plans and specifications for the liquid manure storage areas and determined that they comply with the requirements of Minn. R. ch. 7020, which were established to protect water quality. As an added precaution, the Project’s NPDES/SDS Permit will require that the ground water from the perimeter tile be monitored weekly for signs of discoloration or odor. The weekly examinations will be recorded and kept by the project proposer. Any discoloration or odor changes in the tile line discharge will be reported immediately to the MPCA. The MPCA will then conduct an assessment to determine the source of the discoloration and/or odor change. Based on results of this assessment, an appropriate course of action will be taken, which could include ground-water monitoring and inspection/repair of the concrete manure storage areas.


C. Will the project involve the physical or hydrologic alteration — dredging, filling, stream diversion, outfall structure, diking, and impoundment — of any surface waters such as a lake, pond, wetland, stream or drainage ditch? Yes No

If yes, identify water resource affected and give the DNR Protected Waters Inventory number(s) if

the water resources affected are on the PWI. Describe proposed mitigation measures to avoid or minimize impacts.

5. Manure management.

A. Check the box or boxes below which best describe the manure management system proposed for this feedlot.

Stockpiling for land application Containment storage under barns for land application Containment storage outside of barns for land application Dry litter pack on barn floors for eventual land application Composting system Treatment of manure to remove solids and/or to recover energy Other (please describe)

B. Manure collection, handling, and storage.

Quantities of manure generated: total 1.4 million gallons Frequency and duration of manure removal: number of days per cycle Up to 10 days per barn Total days per year Up to 20

Give a brief description of how manures will be collected, handled (including methods of removal), and stored at this feedlot: The proposer has on file an MMP that has been reviewed by MPCA technical staff to ensure that it meets all federal and state requirements. All manure will be collected and stored in underfloor, reinforced concrete pits. Manure will drop directly into the pits through slatted floors in the barns and be stored in the liquid form. Manure will be agitated and pumped via a towed hose or tank system to the land application sites. Manure will be applied to cropland by injection. All manure will be land applied by a Licensed Commercial Animal Waste Technician.

C. Manure utilization.

Physical state of manure to be applied: liquid solid other - describe:

D. Manure application. 1. Describe application technology, technique, frequency, time of year and locations.

The manure is planned to be removed once per year in the fall, after the crops have been harvested. Manure will be agitated and pumped via a towed hose or tank system to the land application sites. Manure will be applied to cropland by injection. All manure will be land applied by a Licensed Commercial Animal Waste Technician. A map showing the location of land application areas for manure is shown in Exhibit 4.


2. Describe the agronomic rates of application (per acre) to be used and whether the rates are

based on nitrogen or phosphorus. Will there be a nutrient management plan? Yes No

Manure applications rates will be based on the nitrogen needs of the crop. University of Minnesota recommendations will be used for determining allowable nitrogen application rates. Each manure

applicator will be equipped with a flow meter to accurately measure the amount of manure being applied and ensure the desired manure application rate is achieved. Fields receiving manure will only receive commercial fertilizer when the nutrients from the manure are below crop needs (i.e., starter fertilizer).

Soil nitrate testing will be incorporated into the management of fields receiving manure. Soil

samples will be collected to a depth of two feet for soil nitrate testing, as recommended by the University of Minnesota document “Using the Soil Nitrate Test in Minnesota.” This document contains a flow chart that explains when the soil nitrate test can be used reliably for making nitrogen recommendations. Samples will be collected after harvest and results obtained prior to manure application so that adjustments can be made to planned application rates, as needed.

A certified crop advisor will interpret the results of soil nitrate testing and determine the manure application rates needed to satisfy crop nitrogen needs. Soil testing results will be maintained by the Project proposer.

Soil phosphorus levels will be monitored. Soil samples will be collected prior to manure

application. Samples will be taken using the methods described by the Natural Resource Conservation Service document titled, “Soil Sampling and Fertilizer Recommendations” (Fact Sheet MN-NUTR3). Soil testing results will be maintained by the Project proposer.

A certified crop advisor will oversee the soil sampling. Results of the analysis will be reviewed to determine if soil phosphorus levels are increasing over time. In special protection areas, as identified in the MMP, if soil phosphorus levels are greater than 21 parts per million (ppm) Bray, manure must be applied at rates that do not allow soil phosphorus levels to increase over a six-year period. Where field average phosphorus soil test levels exceed 75 ppm within 300 feet of an open tile intake, lake, stream, intermittent stream, drainage ditch without protective berms, or a public waters wetland, or exceed 150 ppm on any other land, then manure must not be applied unless both a) and b) below are met.

a) Manure is managed so that phosphorus additions do not exceed crop phosphorus removal through such practices as dietary management, reduced rates, reduced frequency of applications, or other controls, as follows:

i. For surface applications without incorporation within 24 hours, annual phosphorus

application rates must not exceed crop phosphorus removal in the subsequent crop. ii. For injected or incorporated manure (within 24 hours), manure can not be re-applied

until phosphorus from the previous manure application is removed by subsequent crops (based on the USDA crop uptake research estimates of crop phosphorus removal).

b) Phosphorus transport is controlled by runoff and soil erosion prevention practices in

accordance with a phosphorus strategy documented in the MMP that achieves either:

i. A “very low” or “low” rating with the Minnesota Phosphorus Index originally developed for the animal agriculture Generic Environmental Impact System, and now found at www.mnpi.umn.edu; or

http://www.mnpi.umn.edu


ii. Meets the Natural Resources Conservation Service Technical Standard 590 (May 2001) for soils exceeding the phosphorus thresholds defined above (item 3.b.2).

If soil tests show a phosphorous buildup, the MPCA can, if necessary, require revisions to the MMP and the NPDES/SDS.

3. Discuss the capacity of the sites to handle the volume and composition of manure. Identify any

improvements necessary. Annual manure generation is estimated at 1.4 million gallons at the completion of the Project, based on previous experience with similar operations facilities and management. Each barn has an estimated storage volume of 888,693 gallons, for a total of 1.78 million gallons. The Project will have approximately 15 months of manure storage capacity. The MMP estimates that each year, 456 acres of corn, in a corn and soybean rotation of 912 total acres, will be required for the land application of manure, whereas the proposer has 1,124 acres of land available in this rotation each year.

4. Describe any required setbacks for land application systems. All MPCA and Lac qui Parle County manure application setbacks will be observed. The MPCA setbacks are listed in Table #1 below, and the Lac qui Parle County setbacks are listed in Table #2.

Table #1: MPCA Animal Waste Land Application Setback Distances (in feet)

Non-Winter

With Immediate Incorporation (< 24 hours)

Non-Winter Not incorporated within 24 hours

Feature Winter

With P Management

No PN Management

With Vegetated Buffer

Inadequate Vegetated Buffer

Lake, Stream 300 25 300 100 300 Intermittent Stream* DNR protected wetlands** Drainage ditch w/o quarry*

300 25 300 50 300

Open Tile Intake 300 0 0 300 300 Well, mine or quarry

50 50 50 50 50

Sinkhole with no diversion

Downslope 50 Upslope 300

50 50 Down slope 50 Upslope 300

Down slope 50 Upslope 300

* Intermittent streams and ditches pertain to those identified on USGS quadrangle maps, excluding drainage ditches with berms that protect from runoff into the ditch and segments of intermittent streams which are grassed waterways. USGS quadrangle maps can be found at County Soil and Water Conservation District Offices or can be viewed on the internet at http://www.terraserver.microsoft.com (August 17, 2004).

** Wetland setbacks pertain to all protected wetlands identified on DNR protected waters and wetlands maps (these maps are often located in County Soil and Water Conservation District offices and typically include all wetlands over ten acres).

http://www.terraserver.microsoft.com


Table #2: Lac qui Parle Animal Manure Application and Utilization Setbacks

Surface or Irrigation Applied Incorporated or Injected Location 300 feet 100 feet OHWL Watercourses, streams, rivers, lakes, wetlands

and ditches* 1,000 feet 1,000 feet Municipal wells 200 feet 200 feet Private wells 500 feet 200 feet Residential area (ten or more homes) or

municipality 300 feet 200 feet Residential, neighboring residential or

cemeteries 500 feet 100 feet Urban Expansion Management District Prohibited Yes Ten-year floodplain 100 feet 10 feet Field tile intake * When the area topography slopes away from an adjacent watercourse, animal manure may be exempted from

the required setbacks upon written approval of the Feedlot Administrator and meeting minimum MPCA guidelines.

E. Other methods of manure utilization. If the project will utilize manure other than by land application, please describe the methods.

Not applicable.

6. Air/odor emissions.

A. Identify the major sources of air or odor emissions from this feedlot.

Manure collection and storage facilities, feed storage facilities, animal mortality composting facilities, and manure exposed to the air during land application are the major sources of odor. Dust generated by truck/tractor traffic around the site can also be an odor vector.

B. Describe any proposed feedlot design features or air or odor emission mitigation measures to be implemented to avoid or minimize potential adverse impacts and discuss their anticipated effectiveness. Stored manure will only be agitated immediately prior to the manure being removed for land application and the pit ventilation will be cleaned and serviced on a regular basis to reduce dust accumulation and discharge. During manure application: 1) a Commercial Animal Waste Technician licensed by the Minnesota Department of Agriculture will be used, and all manure will be injected to minimize the release of odors; 2) the number of days during which manure is applied will not exceed 20 days per year; and 3) good manure application sanitation practices will be practiced, such as properly operating manure handling equipment to reduce/eliminate spillage. In addition, the proposer will maintain clean, dry floors; eliminate the buildup of manure; and clean up any spilled feed.

Animal mortalities are to be rendered and will be stored in a dead animal storage unit. The dead animal storage unit will be a totally enclosed structure constructed of wood with an elevated floor and shingled roof. The storage unit will be constructed to keep mortalities from the view of the general public and prevents rodents and scavengers from reaching dead animals. The rendering company will be called as needed as soon as mortalities are discovered and pickup is generally within 36 hours.


C. Provide a summary of the results of an air emissions modeling study designed to compare

predicted emissions at the property boundaries with state standards, health risk values, or odor threshold concentrations. The modeling must incorporate an appropriate background concentration for hydrogen sulfide to account for potential cumulative air quality impacts. An air emission modeling study has been completed for this Project. The air emission modeling results suggest that the proposed Project will comply with the ambient air quality standard for hydrogen sulfide along its effective property lines. The modeling results also suggest that the proposed Project and the neighboring feedlot included in the model will not create exceedences of the subchronic inhalation health risk value (iHRV) for hydrogen sulfide at the nearest neighbors, will not create exceedences of the acute iHRV for ammonia along the proposed property lines, and will not create exceedences of the chronic iHRV for ammonia at the nearest neighbors. The modeling results indicate that detectable concentrations of odorous gases can exist off site; however, the estimated maximum concentration of total volatile odorous organic compounds for the modeled neighbor locations is 10.8 times less than the threshold concentration associated with unpleasant odors. A copy of the Air Emission Modeling Study is included as Exhibit 11.

D. Describe any plans to notify neighbors of operational events (such as manure storage agitation and pumpout) that may result in higher-than-usual levels of air or odor emissions. The Project proposer will avoid land application of manure during holidays and weekends and will notify neighbors when pumping and/or agitating manure storage areas occur.

E. Noise and dust. Describe sources, characteristics, duration, quantities, or intensity, and any proposed measures to mitigate adverse impacts. During construction, normal noise and dust associated with earth-moving equipment and construction will be generated. Adverse impacts as a result of these activities are not anticipated. Following construction, fugitive dust sources are expected to be minimal due to grass seeding around the barns, confinement of the hogs to the farms, and graveled, rather than dirt, driveways. The noise levels present after construction will be consistent with other operations in the area. The main noise from the proposed Project site will come from manure pit ventilation fans, which will be at levels consistent with other feedlot operations in the area. In this case, the distance between the proposed Project site and the nearest neighbor (approximately 3,400 feet) is a significant factor in mitigating any adverse impacts of noise associated with this proposed Project.

Should dust from truck traffic and/or manure application become an issue, the Project proposer will use a dust suppressant to curb further dust emissions from the Project site.

7. Dead Animal Disposal

Describe the quantities of dead animals anticipated, the method for storing and disposing of carcasses, and frequency of disposal. When in full production, the anticipated number of mortalities will be between 360 and 380 finishing hogs per year. Each building will be inspected multiple times per day and dead animals will be removed immediately upon discovery. Rendering will be utilized for dead animals.


The dead animal storage unit will be a totally enclosed structure constructed of wood with an elevated floor and shingled roof. The storage unit will be constructed to keep mortalities from the view of the general public and prevents rodents and scavengers from reaching dead animals. The rendering company will be called as needed as soon as mortalities are discovered and pickup is generally within 36 hours.

8. Surface Water Runoff.

Compare the quantity and quality of site runoff before and after the project. Describe permanent controls to manage or treat runoff. The quantity of stormwater runoff will increase as a result of the additional buildings and impervious surfaces at the site. The construction of the proposed Project will require an NPDES/SDS Stormwater Construction Permit, which includes stormwater and erosion controls during construction, and a permanent stormwater management system once the facility is constructed. The quality of the runoff leaving the site should improve based on the erosion control measures and removing the land from a crop production system and replacing it with permanent ground cover. Stormwater generated at the site will run off to the south and east into cultivated fields adjacent to the site. There is approximately 1,000 feet of field to the road ditch located south of the site.

9. Traffic and Public Infrastructure Impacts.

A. Estimate the number of heavy truck trips generated per week and describes their routing over local roads. Describe any road improvements to be made. The proposer anticipates four to six heavy truck arrivals per week at the site. No road improvements are needed as there are County State Aid Highways adjacent to the Project site.

B. Will new or expanded utilities, roads, other infrastructure, or public services be required to serve the project? Yes No

If yes, please describe.

10. Permits and approvals required. Mark required permits and give status of application:

Unit of government Type of Application Status MPCA NPDES/SDS Permit Pending MPCA Minnesota Feedlot Permit MPCA NPDES/SDS Construction Stormwater Permit Pending

MPCA

Notification/Status Change for Underground Storage Tanks

County Minnesota Feedlot Permit County/Township/City Conditional use or other land use permit Pending DNR Water Appropriation Pending Other*

*(List any other approvals required along with the unit of government, type of approval needed, and status of approval process.)


11. Other potential environmental impacts, including cumulative impacts. If the project may cause any adverse environmental impacts not addressed by items 1 to 10, identify and discuss them here, along with any proposed mitigation. This includes any cumulative impacts caused by the project in combination with other existing, proposed, and reasonably foreseeable future projects that may interact with the project described in this EAW in such a way as to cause cumulative impacts. Examples of cumulative impacts to consider include air quality, stormwater volume or quality, and surface water quality. (Cumulative impacts may be discussed here or under the appropriate item(s) elsewhere on this form.)

Surface Water Quality Land application of manure can be a concern with respect to water quality. The MPCA’s Impaired Waters Database was reviewed to determine whether the facility is in proximity to any existing impaired surface waters in the watershed. The Project (proposed facility and land application areas) lies within the Lac Qui Parle Watershed. There is one water body that appears on the Total Maximum Daily Load 303d Impaired Waters List – the Lac Qui Parle River. The Lac Qui Parle River is impaired for dissolved oxygen and is approximately 1-¾ miles from the site at its closest point. The river flows through one of the manure application sites and within 1/8-mile of another two application sites. The Project operators will follow the MPCA-approved MMP, which is designed to protect water resources and will be an enforceable part of the Project’s NPDES/SDS Permit. Because of the existing concern with dissolved oxygen, it is important to understand that even if a small amount of the manure that is land applied is washed off in some fashion, water quality standards may be violated. This highlights the importance of identifying all conduits to surface water and making sure setbacks and other protective measures are observed as required by the Permit. The protective measures include: manure will be injected into the soil, which significantly reduces the potential for manure and manure-contaminated runoff waters from reaching surface waters; injecting the manure into the soil will also increase the organic matter in the soil making it less likely to erode and add sediment to the impaired waters. As previously outlined in Item 5.D.4 of this document, required setbacks from all surface waters and tile intakes will also be maintained. All of these protective measures help to ensure that none of the manure from the proposed Project will discharge into the intermittent streams that flow into Lac Qui Parle River. As a result, the extent of any potential cumulative effects to surface water quality that are reasonably expected to occur as part of this proposed Project should be minimal. Ground-water Quantity: As described in Item 4.A of this document, an estimated 4.82 million gallons of on-site well water will be required annually at this site to operate the facility after the proposed expansion. The DNR has indicated to the MPCA staff that it does not foresee any problems related to permitting the volumes of water to be appropriated at this site in relation to the water appropriation in the area. Based on the DNR’s comments, the MPCA believes that the water supply for the proposed Project will be adequate, and that the appropriation will not have a significant cumulative effect on the area water supply. Ground-water Quality: To protect ground-water quality, Project proposers are required to follow the requirements specified in Minn. R. ch. 7020 that relate to the construction of manure storage structures and the land application of manure. The proposed facility expansion includes the construction of two confinement barns, each with an eight-foot deep underlying, reinforced concrete pit. With proper construction and maintenance, these pits should adequately contain manure and, therefore, be protective of ground-water quality. While the potential for ground-water impacts does exist, depending on whether seepage occurs and on the location and extent of sand lenses relative to any seepage at the site, this potential is not significant.


Ground-water quality can also be impacted by land application activities where ground water is at or near the surface or is accessible through conduits and fractures commonly associated with karst topography. In this case, ground water is near the surface (less than four feet); however, there is no karst topography in the area. Protective measures include: manure must be applied at crop uptake rates, which minimizes the potential of any contaminants impacting ground water; applicator will be equipped with a flow meter to accurately measure the amount of manure being applied and ensure the desired manure application rate is achieved; and fields receiving manure will only receive commercial fertilizer when the nutrients from the manure are below crop needs (i.e., starter fertilizer). The proposed plans and specifications for the manure storage pits and the MMP for the land application of the manure generated at the proposed facility have been reviewed and approved by the MPCA staff, and will be enforceable conditions of the proposed project’s NPDES/SDS Feedlot Permit. As a result, the extent of any potential cumulative effects to ground-water quality that are reasonably expected to occur as part of this proposed Project should be minimal.

Air Quality The air modeling study that was conducted included one other swine feedlot nearest to the Project in the calculations. The study results suggest that the Project will comply with ambient air quality standards. Air quality computer modeling was performed that estimated concentrations in the air of Hydrogen Sulfide (H2S), Ammonia (NH3), and selected odorous gases from the existing off-site feedlots and the proposed facility. The model estimated pollutant concentrations from the facility and ambient H2S and NH3 background concentrations at the property line and nearest neighbors. A background concentration is the amount of pollutants already in the air from other sources and is used in this evaluation to address cumulative air impacts. Air emissions from other emission sources (e.g., other feedlots or land application activities) may affect the compliance status of the Project, or impact downwind human and environmental receptors. The background level for H2S that was used in the computer model was derived from ambient air quality monitoring at other feedlot facilities in Minnesota. The modeling adds the background air pollutant concentration to the emission concentration predicted from the Project. The results of the modeling study indicate that no significant air quality impacts are expected from the Project (Exhibit 11).

Antibiotic Use Antibiotics will only be used therapeutically at this facility, and then only under the direction of a veterinarian. Flies and Other Insects This facility will utilize a system where liquid manure is stored in underfloor pits. This method of manure storage does not promote the generation of flies because a crust is not likely to form in the pits. If flies do become a problem, the operators will implement industry standard control measures. Rodents and Scavengers Bait stations will be utilized in close proximity to all buildings to control rodents. As described in Item 7 above, heat and covering the compost with sawdust will deter rodents and scavengers from reaching mortalities in the composting facility.

12. Summary of issues. List any impacts and issues identified above that may require further investigation before the project is begun. Discuss any alternatives or mitigative measures that have been or may be considered for these impacts and issues, including those that have been or may be ordered as permit conditions. No other issues.

Air Quality Modeling ReportBrent Dahl Hog Feedlot

Lac qui Parle CountyCerro Gordo TownshipSW � Section 13

March 2007

Exhibit 11

Table of Contents

......................................................................................................................................Introduction 1

............................................................................................................General Modeling Approach 2

..............................................................................................................................Site Descriptions 7

..............................................................................................................Proposed Dahl Feedlot 7

.......................................................................................................Existing Neighbor Feedlot 11

........................................................................................................................Gas Emission Rates 13

......................................................................Hydrogen Sulfide at Property Lines and Neighbors 14

...................................................................................Ammonia at Property Lines and Neighbors 17

...........................................................Odorous Gases at Effective Property Lines and Neighbors 20

.................................................................Total VOOCs at South Property Line and Neighbor Q 23

........................................................................................................................................Summary 25

IntroductionAir quality modeling estimated the atmospheric concentrations of hydrogen sulfide, ammonia,

and selected odorous gases at the effective property lines for the hog feedlot proposed by Brent Dahl (Dahl) and at 22 of the proposed feedlot’s nearest neighbors. Dahl proposes to build two 2,400-head hog-finishing barns. Both barns will store manure in concrete pits located beneath theslatted floors. Dahl has been granted an air quality easement by his father Dennis Dahl and his uncle David Dahl for the SW � of Section 13, Cerro Gordo Township. Thus, the effectiveproperty lines for the proposed Dahl feedlot are the boundaries of the quarter section to the north and east, and the road right-of-ways to the south and west. The gaseous emissions from a neighbor’s hog feedlot were also considered.

The following atmospheric concentrations were calculated:

1. the maximum hourly hydrogen sulfide concentration at the proposed feedlot’s effectiveproperty lines to assess the potential to comply with Minnesota’s ambient air quality standard for hydrogen sulfide of 30 ppb (v/v);

2. the maximum 13-week time-averaged hydrogen sulfide concentration at 22 of the proposed feedlot’s nearest neighbors to assess the potential to exceed Minnesota’ssubchronic inhalation Health Risk Value (iHRV) of 10 �g/m3;

3. the maximum hourly ammonia concentration at the proposed feedlot’s effectiveproperty lines to assess the potential to exceed Minnesota’s acute iHRV for ammonia of 3,200 �g/m3;

4. the maximum annual-averaged ammonia concentration at 22 of the proposed feedlot’snearest neighbors to assess the potential to exceed Minnesota’s chronic iHRV for ammonia of 80 �g/m3; and

5. the hourly concentrations of selected odorous gases (including n-butyric acid and para-cresol) at the proposed feedlot’s effective property lines and at 22 of the proposed feedlot’s nearest neighbors to access the potential for off-site odor episodes.

The above calculations were performed using the CALPUFF air quality model, based on 5 years of historical meteorological data.

The CALPUFF modeling results suggest that the proposed Dahl hog feedlot will comply with the Minnesota ambient air quality standard for hydrogen sulfide. CALPUFF predicted a maximum hourly effective property-line hydrogen sulfide concentration of 11.63 ppb (v/v). When a background concentration of 17 ppb (v/v) is added to the CALPUFF prediction, the

1 Dahl Hog Feedlot Report

maximum property-line hydrogen sulfide concentration is 28.63 ppb (v/v), which is below the ambient standard of 30 ppb (v/v).

The CALPUFF results indicate that the proposed Dahl hog feedlot will not create exceedences of the subchronic hydrogen sulfide iHRV at the neighboring residences. The estimated maximum13-week time-averaged hydrogen sulfide concentration for the feedlot’s neighbors is 0.06 �g/m3.When a background concentration of 1.00 �g/m3 is added to the CALPUFF estimate, the maximum 13-week neighbor hydrogen sulfide concentration is 1.06 �g/m3, which is below the subchronic hydrogen sulfide iHRV of 10 �g/m3.

The modeling results also suggest that the proposed Dahl hog feedlot will not create exceedences of the acute and chronic ammonia iHRVs. CALPUFF predicted a maximum hourly effective property-line ammonia concentration of 1,383 �g/m3. When a background concentration of 148 �g/m3 is added to the CALPUFF prediction, the maximum property-line ammonia concentration is 1,531 �g/m3, which is below the acute ammonia iHRV of 3,200 �g/m3.The estimated maximum one-year time-averaged ammonia concentration for the proposed feedlot’s neighbors is 2.15 �g/m3. When a background ammonia concentration of 5.72 �g/m3 is added to the CALPUFF estimate, the maximum annual ammonia concentration for a neighbor is 7.87 �g/m3, which is below the chronic ammonia iHRV of 80 �g/m3.

Thus, the modeling results suggest compliance with the hydrogen sulfide air quality standard, no exceedences of the subchronic hydrogen sulfide iHRV, and no exceedences of the acute and chronic ammonia iHRVs.

General Modeling ApproachThe modeling approach considered the gaseous emissions from the proposed Dahl finishing

barns and from the finishing barns at a neighbor’s hog feedlot as the only significant and quantifiable emission sources within a 3-mile by 3-mile grid. The air quality impacts associated with the feedlot barns were explicitly modeled. The proposed feedlot was located in middle square mile grid. The air quality impacts associated any other sources in the modeled 3-mile by 3-mile grid were considered implicitly as contributors to the background concentrations that are added to the modeling results. Hence, the background concentrations include the impacts associated with sources such as small feedlots, septic tank vents, fertilizer and manure application to cropland, and wetlands.


The property-line and nearest-neighbor odorous gas concentrations were estimated by the CALPUFF (version 6.112, level 060412) air quality model.1,2,3 The estimated concentrations were based on historical wind speeds, wind directions, atmospheric stabilities, and rural mixing heights. The historical weather data consisted of five years (1987-1991) of surface meteorological data and upper air data from the National Weather Surface station in Huron, South Dakota. The surface and upper air weather data sets were combined into an ISC-typemeteorological file by the U.S. Environmental Protection Agency’s (EPA’s) PCRAMMETsoftware.4 The surface and upper air weather data sets were obtained from the U.S. EPA’sSupport Center for Regulatory Air Models.5

Maximum one-hour, 13-week, and annual average concentrations were calculated. Rural dispersion coefficients were used to characterize atmospheric mixing. The modeling assumed no decay of any modeled gas due to chemical reactions. The modeled receptor height was 0 meters, i.e., ground level. A flat terrain was assumed. All modeled property-line and nearest-neighbor receptors were defined as discrete receptors. Property-line receptors were less than or equal to 25 meters apart. An arbitrary Cartesian coordinate system (x, y) was used with the southwest corner of Section 13 (Lac qui Parle County, Cerro Gordo Township) as the origin (0, 0). Positive values of x represent distance east of the origin. Positive values of y represent distance north of the origin.

To assess the potential for environmental impacts, the atmospheric concentrations of hydrogen sulfide, ammonia and volatile odorous organic compounds (VOOCs) generated by the air qualitymodeling were compared to air quality standards, inhalation Health Risk Values (iHRVs), and published odor threshold concentrations. The direct comparison of the model-generated concentrations to these environmental threshold concentrations does not consider the impact of different averaging times. EPA guidelines do not allow concentrations to be time averaged for time periods less than an hour.6 This is important because the Minnesota ambient air quality


1 U.S. EPA. 1995. A User’s Guide for the CALPUFF Dispersion Model. U.S. Environmental Protection Agency,Office of Air Quality Planning and Standards, Research Triangle Park, NC, EPA-454/B-95-006.

2 Scire J. S., Strimaitis D. G., and Yamarino R. J. 2000. A User’s Guide for the CALPUFF Dispersion Model (Version 5). Earth Tech, Inc., Concord, MA. 496 pp.

3 U.S. EPA. 2003. Revision to the Guideline for Air Quality Models. 40 CFR Ch. 1, Part 51, Appendix W (April 15, 2004 Edition).

4 U.S. EPA. 1999. PCRAMMET User’s Guide. U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, NC. EPA-454-B-96-001 (Revised June 1999).

5 www.epa.gov/ttn/scram


standards for hydrogen sulfide are based on average concentrations over a 30-minute time periodand because the published odor threshold concentrations for VOOCs are often based on instantaneous measurements. For example, an hourly model-generated hydrogen sulfide concentration of 29 ppb (v/v) may contain a half-hour average concentration that exceeds the 30 ppb standard. Also, an odor intensity that an odor panelist may find to be merely detectable in a short-term field measurement could be annoying if present for an hour or longer.

The background concentrations of hydrogen sulfide and ammonia provided in Table 1 were added to the CALPUFF estimated concentrations as described in EPA guidelines.7 The listed concentrations represent background concentrations for rural Minnesota. The listed 17-ppb background hydrogen sulfide concentration is appropriate when assessing a feedlot’s potential to comply with the 30-ppb standard. A background concentration of 18 ppb should be used in assessing the potential to comply with the 50-ppb hydrogen sulfide standard.

Table 1. Background concentrations.

Gas

HourlyBackground

Concentration

13-WeekBackground

Concentration

AnnualBackground

Concentration

Hydrogen Sulfide 17 ppb (v/v)(24.3 �g/m3)

0.70 ppb (v/v)(1.00 �g/m3)

Not Required

Ammonia 208 ppb (v/v)(148 �g/m3)

Not Required 8.07 ppb (v/v)(5.72 �g/m3)

The background concentrations listed in Table 1 are not the time-averaged concentrations obtained from monitoring. Instead, the listed concentrations reflect the monitored data expressed in the terms of the “exceedence or violation condition” for the corresponding iHRV guideline or



ambient standard. For example, the background 208-ppb ammonia concentration for the acute ammonia iHRV represents the maximum hourly concentration that occurred within the entire length of monitoring. This is the appropriate interpretation of background for the acute ammonia iHRV, because the guidance is concerned with any potential exceedence of the iHRV. Also, the17-ppb hydrogen sulfide background represents the third highest 30-minute concentrationthat occurred within any 5-day period. This is appropriate, because the ambient hydrogensulfide standard defines a violation as the third exceedence of 30-ppb within any 5-dayperiod.

To assess the potential for odor episodes, the estimated atmospheric concentrations of hydrogen sulfide, ammonia, and the VOOCs were compared to each gas’s reported odor threshold concentration. The odor threshold concentration is defined as the gas-phase concentration at which 50 percent of the population can detect the gas’s odor. For this presentation, odor number is defined as the ratio of the estimated atmospheric concentration for aspecific odorous gas divided by the gas’s odor threshold concentration. An odor number equal to 1 suggests that 50 percent of the population can detect the estimated atmospheric concentration for a specific gas. An odor number greater than 1 suggests that more than 50 percent of the population can detect the gas, while a value less than 1 indicates that less than 50 percent of the population can detect the gas. Typically, an odor number below about 0.1 suggests that less than 1 percent of the population can detect the gas.8 The odor threshold concentrations used in this assessment are presented in Table 2.

The odor-number assessment of odor intensity does not consider the interactions between gases. Gas mixtures can intensify or mitigate certain odors. The Zahn correlation9,10 was used to account for the odor intensity associated with the mixture of gases released from the manure pits.The total concentration of volatile odorous organic compounds (VOOCs) required for the Zahn correlation was calculated from the modeled concentrations of the 12 organic gases listed in Table 2.


8 Nagy G. Z. 1991. The odor impact model. Journal of Air & Waste Management Association 41(10): 1360-1362.

9 Zahn J. A. 1997. Swine odor and emissions from pork production. In: McGuire K. (ed.), Environmental AssuranceProgram, National Pork Producers Council, Des Moines, IA, pp. 20-122.

10 Zahn J. A., Hatfield J. L., Laird D. A., Hart T. T., Do Y. S., and DiSpirito A. A. 2001. Functional classification of swine manure management systems based on effluent and gas emission characteristics. Journal of EnvironmentalQuality 30: 635-647.

Table 2. Odor threshold concentrations for the modeled gases.11

Odorous Gas

Odor ThresholdConcentration

(ppb, v/v)

Acetic Acid 200n-Propanoic Acid 17iso-Butyric Acid 11n-Butyric Acid 0.69iso-Valeric Acid 4.8n-Valeric Acid 0.28iso-Caproic Acid 7.7n-Caproic Acid 21n-Heptanoic Acid 5.0

Phenol 76para-Cresol 0.25para-Ethyl Phenol 1.2

Hydrogen Sulfide 3.7Ammonia 1,500


11 Minnesota Environmental Quality Board. 1999. A Summary of the Literature Related to the Social, Environmental, Economic and Health Effects: Volume 2. Generic Environmental Impact Statement on AnimalAgriculture, Prepared by the University of Minnesota, September 1999. Table 2 presents the geometric mean of the lower and upper odor threshold concentrations obtained from this reference.

Site Descriptions

Proposed Dahl FeedlotThe proposed Dahl feedlot will consist of two hog-finishing barns. The physical characteristics

of the proposed hog-finishing barns are provided in Table 3. The modeled locations of the two barns are provided in Figure 1. The setback distances to the effective property lines are provided in Figure 2 and range from 975 feet to 1358 feet.

The proposed air quality modeling estiamted the atmospheric gas concentrations at the 22 neighboring residences shown in Figure 3.

Table 3. Dimensions and capacities of the proposedfinishing barns at the Dahl hog feedlot.

HogFinishing

Barn

BarnLength(feet)

BarnWidth(feet)

BarnHeight(feet)

Number ofHoused

Pigs

North (proposed) 196 102 22 2,400South (proposed) 196 102 22 2,400


85' 69'

429'

350'

N

E

S

W

(1190', 938')

North Finishing Barn

South Finishing Barn

85'

70'

70'

Figure 1. Modeled gaseous emission sources and property lines for the proposed Dahl hog feedlot. The shaded squares represent the subsources used to characterize the barns. The separation distance between the barns is 70 feet.


(33', 33')

1358'

975'

1169'1242'

N

E

S

W

2607'

2607'

Figure 2. Modeled locations of the proposed Dahl hog barns (blue-bordered rectangles), feedlot property lines (red-bordered rectangle), and the effective property lines (green-bordered rectangle).


Figure 3. Modeled locations for the proposed Dahl hog feedlot, the existing Neighbor Feedlot, and 22 of the proposed feedlot’s nearest neighbors. The green-bordered rectangle represents the boundaries of the air quality easement.


Existing Neighbor FeedlotThe existing Neighbor Feedlot is located in the NE � of Section 24, Cerro Gordo Township

and consists of two hog-finishing barns. The physical characteristics of the barns are provided in Table 4. The modeled locations of the barns are provided in Figure 4.

Table 4. Dimensions and capacities of the hog-finishing barnsat the existing Neighbor Feedlot.

HogFinishing

Barn

BarnLength(feet)

BarnWidth(feet)

BarnHeight(feet)

Number ofHoused

Pigs

North (existing) 328 51 18 2,000South (existing) 328 51 18 2,000


(2640', -2640')

1551'

245'

2590'

2590'

857'

2017'

N

E

S

W

NorthFinishing

Barn

SouthFinishing

Barn

Figure 4. Modeled gaseous emission sources for the existing Neighbor Feedlot.


Gas Emission RatesThe two proposed hog-finishing barn at the Dahl feedlot and the two existing hog-finishing

barns at the Neighbor Feedlot were modeled as sources of hydrogen sulfide, volatile odorous organic compounds (VOOCs), and ammonia. The emission rates of hydrogen sulfide and the 12 VOOCs from the manure pits were estimated using the PitEmissions software (version 4.1)based on the chemical characteristics of manure stored in pits located beneath the hog-finishingbarns. PitEmissions is based on the mass-transfer algorithms recommended by the U.S. EPA to estimate emission rates.12 For west-central Minnesota, the typical characteristics of stored hog manure are provided in Table 5.

The ammonia emission rate for the hog-finishing barns were based on the finishing-pig ammonia emission rate factor of 3.7 kg NH3/head/yr.13 This emission factor represents the ammonia emissions on an annual basis. To account for temperature variations on ammonia emissions from the pitted barns, the respective “stable + manure” ammonia emission factors was multiplied by the monthly scalars developed by the Minnesota Pollution Control Agency(MPCA).

Table 5. Chemical characteristics of manure in pitted hog-finishing barns.14

Parameter Units Value

Temperature °C 10.5pH -log10[H+] 7.2Volatile acids mg HOAc/L 19,0004-AAP phenolics mg/L 64.1Total dissolved sulfide mg S/L 13.8


12 U.S. EPA. 1994. Air Emissions Models for Waste and Wastewater. U.S. Environmental Protection Agency, Officeof Air Quality Planning and Standards, Research Triangle Park, NC, EPA-453/R-94-080A.

13 U.S. EPA. 2002. Review of Emissions Factors and Methodologies to Estimate Ammonia Emissions from AnimalWaste Handling. U.S. Environmental Protection Agency, Office of Research and Development, Research TrianglePark, NC, EPA-600/R-02-017.

14 MPCA. 2003. Hancock Pro-Pork Hog Feedlot Project. Final Environmental Impact Statement. Minnesota Pollution Control Agency, September 15, 2003.

Hydrogen Sulfide at Property Lines and NeighborsThe CALPUFF results suggest that the proposed Dahl hog feedlot will comply with the

Minnesota ambient air quality standard for hydrogen sulfide. The estimated maximum hourly effective property-line concentrations for the proposed feedlot are provided in Table 6. When a background concentration of 17 ppb (v/v) is added to the CALPUFF-generated concentrations, the maximum estimated effective property-line hydrogen sulfide concentration is 28.63 ppb, which is below the standard of 30 ppb.

Table 6. Maximum hourly effective property-line hydrogen sulfide concentrations.

EffectiveProperty Line

H2S ConcentrationWithout Background

(ppb, v/v)

H2S ConcentrationWith a 17 ppb (v/v)Background Value

(ppb, v/v)

North 8.68 25.68East 6.13 23.13South 11.63 28.63West 5.81 22.81

The maximum CALPUFF-generated hourly hydrogen sulfide concentrations (without background) are plotted in Figure 5. The plotted 3-ppb concentration isopleth overestimates the maximum extent of detectable hydrogen sulfide odors without background, because the reported odor threshold concentration for hydrogen sulfide is 3.7 ppb (Table 2). Figure 5 suggests that detectable concentrations of hydrogen sulfide will exist beyond the boundaries of the air quality easement, i.e., beyond the boundaries of the SW � of Section 13.


3

3

3

813

8

-1

0

1

2

-1 0 1 2

North/SouthDistance (miles)

East/West Distance (miles)

Figure 5. Maximum CALPUFF-generated hourly hydrogen sulfide concentrations in ppb (v/v) for the proposed Dahl hog feedlot and the existing Neighbor Feedlot. The contour lines represent 3, 8, and 13 (v/v) of hydrogen sulfide. The plotted concentrations do not include the 17-ppb background hydrogen sulfide concentration. The point (0, 0) is the southwest corner of Section 13.

The CALPUFF results also suggest that the combined emissions from the proposed Dahl hog feedlot and the existing Neighbor Feedlot will not cause exceedences of the subchronic hydrogensulfide iHRV at the neighboring residences. The estimated maximum 13-week time-averaged hydrogen sulfide concentrations for each of the 22 modeled nearest neighbors are provided in Table 7. When a background concentration of 1.00 �g/m3 is added to the CALPUFF-generatedconcentrations, the maximum 13-week hydrogen sulfide concentration is 1.06 �g/m3, which is below the subchronic iHRV for hydrogen sulfide of 10 �g/m3.


Table 7. Maximum 13-week time-averaged hydrogen sulfide concentrationsfor 22 of the proposed feedlot’s nearest neighbors.

Neighbor

Maximum 13-week H2SConcentration Without

Background(�g/m3)

Maximum 13-Week H2SConcentration With a

1.00 �g/m3 Background(�g/m3)

A 0.01 1.01B 0.03 1.03C 0.04 1.04D 0.03 1.03E 0.02 1.02F 0.02 1.02

G 0.01 1.01H 0.01 1.01I 0.01 1.01J 0.01 1.01K 0.02 1.02

L 0.02 1.02M 0.06 1.06N 0.05 1.05O 0.02 1.02P 0.03 1.03

Q 0.04 1.04R 0.05 1.05S 0.03 1.03T 0.03 1.03U 0.03 1.03V 0.02 1.02


Ammonia at Property Lines and NeighborsThe CALPUFF-generated maximum hourly property-line ammonia concentrations are

provided in Table 8. The highest estimated property-line concentration with a background concentration of 148 �g/m3 is 1,531 �g/m3, which is below the acute iHRV for ammonia of 3,200 �g/m3. Thus, the modeling results suggest that the proposed Dahl hog feedlot will not result in exceedences of the acute ammonia iHRV.

Table 8. Maximum hourly property-line ammonia concentrations.

EffectiveProperty Line

NH3 ConcentrationWithout Background

(�g/m3)

NH3 ConcentrationWith a 148 �g/m3

Background Value(�g/m3)

North 1,177 1,325East 697 845South 1,383 1,531West 690 838

The maximum CALPUFF-generated hourly ammonia concentrations (without background) areplotted in Figure 6. The reported odor threshold concentration for ammonia is 1,067 �g/m3 or 1,500 ppb v/v (Table 2). The plotted 1,000-�g/m3 isopleth overestimates the maximum extent of detectable ammonia odors. Table 7 suggests that detectable concentrations of ammonia will be largely confined to the boundaries of the air quality easement, i.e., within the boundaries of the SW � of Section 13.


500

1,0001,500

5001,000

-1

0

1

2

-1 0 1 2



Figure 6. Maximum CALPUFF-generated hourly ammonia concentration in �g/m3

for the proposed Dahl hog feedlot and the existing Neighbor Feedlot. The contour lines represent 500, 1,000, and 1,500 �g/m3 of ammonia. The plotted concentrations do not include the 148 �g/m3 background ammonia concentration. The point (0, 0) is the southwest corner of Section 13.

The CALPUFF-generated annual-average ammonia concentrations for the proposed feedlot’s22 nearest neighbors are provided in Table 9. The highest annual ammonia concentration with a background concentration of 5.72 �g/m3 is 7.87 �g/m3, which is below the chronic ammonia iHRV of 80 �g/m3.


Table 9. Maximum annual nearest-neighbor ammonia concentrations.

Neighbor

NH3 ConcentrationWithout Background

(�g/m3)

NH3 ConcentrationWith a 5.72 �g/m3

Background Value(�g/m3)

A 0.47 6.19B 1.05 6.77C 1.18 6.90D 1.14 6.86E 0.77 6.49F 0.59 6.31

G 0.45 6.17H 0.36 6.08I 0.30 6.02J 0.49 6.21K 0.80 6.52

L 0.67 6.39M 2.15 7.87N 1.77 7.49O 0.54 6.26P 0.88 6.60

Q 1.16 6.88R 1.89 7.61S 0.90 6.62T 0.99 6.71U 0.99 6.71V 0.76 6.48


Odorous Gases at Effective Property Lines and NeighborsThe CALPUFF modeling effort estimated the atmospheric concentrations of selected odorous

gases at the effective property lines for the proposed Dahl hog feedlot and at 22 of the feedlot’snearest neighbors. The estimated maximum effective property-line concentrations for the 6 gaseswith the highest concentrations relative to their odor threshold concentration are provided in Figure 7. The highest effective property-line concentrations are for ammonia (2,144 ppb, which includes a background concentration of 208 ppb), hydrogen sulfide (28.63 ppb, which includes a 17 ppb background concentration), propanoic acid (2.95 ppb), n-butyric acid (1.72 ppb), para-cresol (0.88 ppb), and n-valeric acid (0.29 ppb).

The corresponding odor numbers for the maximum effective property-line concentrations are provided in Figure 8. The gases with an odor number greater than 0.1 were hydrogen sulfide (7.74), para-cresol (3.51), n-butyric acid (2.49), ammonia (1.43), n-valeric acid (1.04), and propanoic acid (0.17). The other modeled gases are assumed to be non-detectable as individual gases, because their individual odor numbers were less than 0.1. Population response curves suggest that 99 percent of the population could detect the estimated maximum effective property-line hydrogen sulfide concentration, 95 percent the para-cresol concentration, 90 percent the n-butyric acid concentration, 70 percent the property-line ammonia concentration, 52 percent the n-valeric acid concentration, and 2 percent the propanoic acid concentration.

The estimated maximum hourly nearest-neighbor concentrations for the 6 gases with highest concentrations relative to their odor threshold concentration are provided in Figure 9. Thehighest maximum estimated hourly concentrations were for ammonia (663 ppb, which includes abackground concentration of 208 ppb), hydrogen sulfide (19.11 ppb, which includes a background concentration of 17 ppb), propanoic acid (0.54 ppb), n-butyric acid (0.31 ppb), para-cresol (0.16 ppb), and n-valeric acid (0.05 ppb).

The calculated odor numbers corresponding to the maximum hourly concentrations are provided in Figure 10. The individual gases with an odor number greater than 0.1 were hydrogensulfide (5.17), para-cresol (0.64), n-butyric acid (0.45), ammonia (0.44), and n-valeric acid (0.19). The other modeled gases are assumed to be non-detectable, because their individual odor numbers were less than 0.1. Population response curves suggest that 98 percent of the populationcould detect the estimated maximum neighbor hydrogen sulfide concentration, 26 percent the para-cresol concentration, 13 percent the n-butyric acid concentration, 13 percent the ammonia concentration, and 2 percent the n-valeric acid concentration. The population response curves assume the presence of individual gases.


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Figure 7. Maximum hourly effective property-line concentrations.

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Figure 8. Maximum hourly effective property-line odor numbers.


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Figure 9. Maximum hourly neighbor concentrations.

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Figure 10. Maximum hourly neighbor odor numbers.


Total VOOCs at South Property Line and Neighbor QThe empirical Zahn correlation relates the total gas-phase volatile odorous organic compound

(VOOC) concentrations for the gases emitted from manure storage facilities to the perceived odor intensity as determined by odor panels. The sum of the individual maximum VOOCconcentrations from the CALPUFF modeling effort was multiplied by 1.18 to account for all of the VOOC gases included in the Zahn correlation. As indicated in Figure 11, the maximum VOOC concentrations (with the 1.18 correction) obtained from the CALPUFF modeling effortare 36.0 �g/m3 for the proposed Dahl hog feedlot’s effective south property line and 6.5 �g/m3

for Neighbor Q.

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OdorIntensity

Total VOOC Concentration (�g/m3)

Zahn

South EffectiveProperty-Line

Neighbor Q

Unbearable

Very Unpleasant

Unpleasant

Neutral

Pleasant

Figure 11. Comparison of CALPUFF-generated maximum hourly total VOOC concentrations for the proposed Dahl hog feedlot’s south effective property line and for the modeled location of Neighbor Q. The modeling results suggest that theproposed feedlot will not create unpleasant off-site odors.

The Zahn correlation suggests that a total VOOC concentration of about 10 �g/m3 corresponds to a detectable but “neutral” odor intensity. Total VOOC concentrations have to exceed about 70 �g/m3 before the odor intensity is “unpleasant.” At the proposed Dahl feedlot’s south effective


property-line, the maximum CALPUFF-generated total VOOC concentration is 1.9 times less than the total VOOC concentration associated with “unpleasant” odor intensities. At the modeledNeighbor-R location, the maximum CALPUFF-generated total VOOC concentration is 10.8 times less than the total VOOC concentration associated with “unpleasant” odor intensities. Thus, the CALPUFF modeling results suggest that the proposed feedlot’s effective property-linesand nearest neighbors will not be subjected to offensive odors.

The maximum CALPUFF-generated hourly total VOOC concentrations (with the 1.18 correction factor) are plotted in Figure 12. The Zahn correlation suggests that a total VOOCconcentration of about 10 �g/m3 can be considered as the odor detection threshold. Figure 12 suggests that detectable total VOOC concentrations (greater than 10 �g/m3) will exist beyond theboundaries of the air quality easement, i.e., beyond the boundaries of the SW � of Section 13.

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Figure 12. Maximum CALPUFF-generated hourly total VOOC concentrationsin �g/m3 for the proposed Dahl hog feedlot and the existing Neighbor Feedlot. The contour lines represent total VOOC concentrations of 10, 20, 30, and 40 �g/m3. Theplotted concentrations include the 1.18 correction factor. The point (0, 0) is the southwest corner of Section 13.


SummaryThe CALPUFF modeling results suggest that the proposed Dahl hog feedlot will comply with

the ambient air quality standard for hydrogen sulfide. The CALPUFF results also suggest that theproposed feedlot will not create exceedences of the subchronic iHRV for hydrogen sulfide, the acute iHRV for ammonia, and the chronic iHRV for ammonia. The CALPUFF modeling results indicate that detectable concentrations of odorous gases can exist off site. However, the estimated maximum concentration of total VOOCs for the modeled neighbor locations is 10.8 times less than the threshold concentration associated with unpleasant odors.


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Brent Dahl Swine Feedlot Project Environmental Assessment ... · Brent Dahl is proposing to construct two 2,400-head hog total confinement finishing barns (Project) in the SE¼ of