MANKATO — The CHS soybean processing facility on South Riverfront Drive — one of Mankato’s largest industrial plants and a major emitter of air pollutants — is expected to receive approval Monday for an expansion.
The City Council is poised to authorize a conditional use permit for construction of a 147-foot soybean oil bleaching and deodorization tower at the plant, which is still commonly known by its original name of Honeymead.
The permit is on the council’s “consent agenda,” which is reserved for noncontroversial items expected to pass on a single combined vote without comment.
The CHS expansion will allow the plant to refine an increased amount of soybean oil from the company’s Fairmont plant, which has upped production by 20%, while also modernizing the Mankato facility, which dates back to the 1950s, according to a document provided to the city describing the project.
“New, more efficient and higher capacity equipment will replace existing equipment and will be sited in a slightly new configuration within the confines of our site,” the document states. “Project completion is expected in late summer 2023.”
The facility will serve the stage of the soybean oil refining process that subjects the oil to high-pressure steam and a low-pressure vacuum, which work together to remove red and yellow coloring and chemicals such as free fatty acids, aldehydes, ketones, peroxides and others that produce unsavory odors.
“The combined effect of the low vacuum and the stripping steam produces the bland-tasting light-colored oil, which meets consumer acceptance,” according to the publication “Practical Guide to Vegetable Oil Processing.”
A high-pressure steam generator, powered by natural gas, will be part of the new facility, which will be located in the southwestern quadrant of the sprawling plant. At 147 feet, the new structure will be the equivalent of a 10-14 story building but will still be about 20 feet short of the highest existing structure on site.
The company pledged to continue to work toward being a quieter and less noticeable neighbor to Sibley Park and nearby residential areas.
“CHS is committed to continue efforts to reduce dust and emissions throughout the facility. Most of the vegetable oil refining process has no emissions or is considered insignificant,” the document filed with the city states.
The plant does produce less total monitored air pollution than facilities such as the ADM soybean plant on Third Avenue or the Wilmarth power plant, according to Minnesota Pollution Control Agency data.
But CHS tops those facilities in the “air toxic” category, which includes pollutants that “at sufficient concentrations” cause or may cause “serious health effects or adverse environmental and ecological effects.”
The level of emissions from CHS, however, are not exceeding MPCA or federal Environmental Protection Agency standards, and that will continue to be the case after the expansion, according to a company statement provided to The Free Press.
“CHS has operated and will continue to operate within all legal limits set by the EPA and the state of Minnesota,” stated Tom Ryan, senior director of corporate communications.
The conditional use permit set to be approved by the city includes conditions requiring the plant to continue to meet regulatory standards for emissions and noise and also mandates that the expansion can not increase the facility’s water usage or wastewater generation by more than 10%.
A noise-impact study commissioned by CHS determined that the new facility would slightly exceed nighttime limits at the nearest homes with standard equipment but that the noise would fall just below the required level if additional noise-dampening gear was included. The company says it will install the extra equipment and the city permit mandates it.
According to the private noise analysis, which was based on figures CHS provided to the consultant from a facility it owns in Hallock, the total noise impact would be 51.1 decibels without the enhanced noise-reduction equipment. The state requires a facility to not be above 50 decibels for more than 50% of any hour between 10 p.m. and 7 a.m.
With the additional noise-dampening measures, the total noise impact of the new facility will be 49.4 decibels at the nearest homes, according to the consultant, SBP Associates, Inc. of Deerwood.
Among more than a dozen conditions recommended by city staff, the city permit will require CHS to supply a list of contacts — including cell phone numbers — of CHS employees available to handle complaints from the public, provide to the city the plant’s updated MPCA permit and take steps to control light pollution coming from the site.
The conditional use permit also attempts to improve the appearance of the plant, a heavy-industrial property that stands in sharp contrast to its immediate neighbors — Mankato’s premier municipal park and residential areas consisting mostly of small single-family houses.
“The applicant shall provide a landscaping plan that brings the property into conformance with the Mankato City Code, and landscaping shall be installed in conjunction with the operation,” the proposed city permit states.
While opinions may vary about the aesthetic value of the complex, even with more landscaping, the facility is a powerhouse in the local economy and an important buyer for area soybean growers, something Ryan emphasized in the statement from CHS.
“The soybean refinery expansion and renovation project, driven by strong global demand, will allow us to process more of our local farmers’ soybeans into value-added products, while providing over 225 good-paying jobs and economic growth for Blue Earth and surrounding counties,” Ryan said.
Even before the expansion, the estimated market value of the 26.8-acre complex is nearly $12.2 million, according to county tax records. CHS is scheduled to pay $365,000 in property taxes this year to the city, county and school district.