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Predicting Odor Consequences of a Large Confinement Hog Rearing Operation

Burnett County, Wisconsin

Featured image for the project, Predicting Odor Consequences of a Large Confinement Hog Rearing Operation

Image Courtesy of KnowCAFOs

Through the Thriving Earth Exchange (TEEx) network, we identified two scientists interested in assisting with project goals. Sudheer Bhimireddy, a post-doctoral researcher at the University of Illinois Urbana-Champagne, used a widely accepted transport and dispersion model (HYSPLIT) to generate data about the frequency and occurrence of odor from a proposed hog concentrated animal feeding operation (CAFO) in northwest Wisconsin. Katie Kurowski, a Ph.D. student at Johns Hopkins University developed an annotated bibliography of peer-reviewed literature concerning air quality impacts from hog CAFOs, including health, quality of life, recreation revenue, and property values. The information from these documents contributed to two popular press articles concerning the proposed facility and will likely be part of an on-going lawsuit. Although not directly tied to the TEEx activities, the Wisconsin Department of Natural Resources has rejected the developer’s application for permission to construct the facility; such a rejection is unprecedented in Wisconsin.


About the Community

Trade Lake Township is a rural community located in northwest Wisconsin. It is a low, flat landscape interspersed with glacial ridges, wetlands, streams, and lakes. Residents are a blend of unique individuals drawn to the area by a common love for nature, clean air, and respect for the environment, with an orientation to outdoor activities.  Small scale agriculture is part of the local economy, though the majority of local economic activity is recreation, tourism, and second homes oriented to its many lakes and rivers.  The community has a strong social fabric, built on the love of the land, nature, wildlife, clean water, and clean air to breathe.

Trade Lake is located within the watershed for the St. Croix National Scenic Riverway. Ojibwa Indians traded goods with the Swedish immigrants that settled here, hence the town, lake and river’s namesake. Some forested lands were cleared for farms that now dot the countryside. Most of the farmers here are multi-generation farmers, are good stewards of the environment, and good neighbors with other rural residents. Trade River Forest and Wetlands is a designated State Natural Area (SNA); it has the highest bird species richness of any site surveyed in the Governor Knowles State Forest and includes two rare birds along with several species of greatest conservation need according to the Wisconsin Department of Natural Resources (WDNR).


The Project as It was Planned

Protecting clean air and water is a desire all residents of the area share. The pollution and resulting threats to the local environment posed by a proposed industrial-scale hog factory fuel a desire for education on how to protect the health of our community.  Through a non-profit organization – KnowCAFOs – the community identified three goals as part of initial engagement with TEEx:

  1. Seek scientific information regarding the impacts of water contamination and airborne pollutants (odor, sulfur dioxide, ammonia, bacteria and other) on health, quality of life, and property values.
  2. Establish reliable ways to measure harmful emissions to protect public health and the environment.
  3. Support sustainable farming practices and push regulators to better enforce clean air and clean water laws in order to protect our communities.

The Project as It Happened

The project started with a protracted period of discussion about which potential impacts of a large hog CAFO might benefit from outside expertise through Thriving Earth. This included evaluating the applicant’s nutrient management plan and maps of manure spreading restrictions. The Thriving Earth science fellow (Steve Ventura, professor emeritus, University of Wisconsin-Madison) used the model and mapping tool SNAP-Plus, used by WDNR for regulatory purposes, for this evaluation. It confirmed what KnowCAFOs participants believed were significant threats to ground and surface waters from hog waste disposal. Since this information was already part of the public discussions, the team decided to focus on air quality related impacts (odor, noxious gases, health impacts, impairment of quality of life, diminution of property values). Three specific objectives in this area were developed as part of a work plan.

  1. Document existing scientific information related to air quality impacts of large CAFOs.

Katie Kurowski, a Ph.D. student at Johns Hopkins University, developed an annotated bibliography of peer-reviewed and other literature concerning air quality impacts from hog CAFOs, including health, quality of life, recreation revenue, and property values. The bibliography has been provided to KnowCAFOs. It will enhance a list of citations that was already assembled in support of operating condition ordinances adopted by the Town of Trade Lake and other nearby towns. The articles in the public domain are at:

The annotated summaries of all the articles are at:

  1. Modeling intensity and duration, volume, and concentration of air pollutants

Sudheer Bhimireddy, a post-doctoral researcher at the University of Illinois Urbana-Champagne, used a widely accepted transport and dispersion model (HYSPLIT) to generate data about the frequency and occurrence of odor from a proposed hog concentrated animal feeding operation in Trade Lake (southern Burnett County, WI). Animal numbers (equated to waste generation volume) and facility design parameters were derived from applicant data in the public domain. Terrain and wind data came from public domain federal data sources. The model generated quantitative values of “odor units” for a test period during spring 2023. In general terms, the modeling revealed an extensive area around the proposed facility that would be impacted by odor (and associated gases such as hydrogen sulfide and ammonia), in some cases up to several miles away from the facility. The report also documents a general procedure for evaluating impacts under other facility emission factors and atmospheric or terrain conditions. The summary report is available at:

  1. Property value impacts

A third objective was identified on an “if possible” basis – to quantify potential impacts on property values from projected odor (and water/groundwater) impacts of the facility. For several reasons, this objective was not pursued as part of the TEEx collaboration.

Although it cannot be directly attributable to the Thriving Earth products, the WDNR (state environmental regulatory agency) rejected the Wisconsin Pollution Discharge Elimination Discharge permit application (water quality protection as part of the 1972 Clean Water Act) and the state livestock siting act (WI DATCP Ch. 93.90). This was a surprising and welcome outcome for KnowCAFOs, as it was unprecedented. The group did point out to regulators and other leaders that the application was seriously flawed in several aspects, including lack of evidence that the applicants obtained permission to spread manure in fields that were part of their nutrient management plan, and inadequate evaluation of odor and noxious gas emissions.

This Thriving Earth project is now considered completed, though the CAFO siting issue itself is not finished. The applicant has put in a placeholder with WDNR to submit another application, a lawsuit has been filed against one of the Towns on record opposing the facility, another lawsuit is threatened, two popular press articles about the controversy will be released this summer (2023). The scientific information generated through the Thriving Earth collaboration have the potential to be part of all these deliberations.

Check out the two page summary for the Community here.

Project Team

About the Community Leads:

KnowCAFOs, Inc. is a non-profit educational corporation that is concerned about water, air, and rural quality of life in northwest Wisconsin. Its members include residents and visitors to the area concerned about threats to natural resources and recreational opportunities. The group is particularly focused on proposals for Concentrated Animal Feeding Operations (CAFOs) that are targeting northwest Wisconsin, bringing with them the potential to crush family farms, tourism, and property values. More information about the organization and the proposal described in this report can be found at

Community Scientists

Katie Kurowski is a doctoral candidate in the Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University. She earned an MPH degree with a focus in infectious diseases and vaccinology from UC Berkeley in 2020. She is interested in One Health approaches to infectious disease spread and how the human-environment interface can impact infectious diseases. Katie’s dissertation research looks at respiratory pathogen immunity among neighbors and workers in high density industrial livestock operation areas.

Sudheer Bhimireddy is a postdoctoral research associate with the Illinois State Water Survey at the University of Illinois-Urbana Champagne. His research interests include atmospheric boundary layer physics, boundary layer turbulence, numerical modeling of atmospheric flows, and numerical modeling of extreme events. He earned a Ph.D. in Mechanical Engineering from the University of Texas at San Antonio and M.S. in Ocean Engineering from Indian Institute of Technology at Madras.

Community Science Fellow 

Steve Ventura headshot

Steve Ventura is professor emeritus of Soil Science and Environmental Studies at the University of Wisconsin-Madison. Expertise in remote sensing and GIS led him into many application domains, including natural resource management, environmental protection, land tenure, community and regional food systems, water quality and quantity, and biofuel production systems. Recent research and outreach focused on soil heavy metal contamination and urban agriculture.