By Jared Strong
An ethanol plant just west of Sioux Center that has operated for an unknown number of years without air filtration equipment on one of its grain bins was recently fined $10,000 by the Iowa Department of Natural Resources.
Siouxland Energy Cooperative has been required for about 20 years to filter dust from the air emitted by a corn bin. The company had repeatedly noted in its communications with the DNR over that period of time that the emissions control equipment was in place, according to a DNR administrative order.
But last year, the company asked to modify a permit to remove the requirement for the filter equipment because the company “apparently had removed the control equipment from the corn bin,” the order said.
Siouxland Energy representatives told the DNR in November 2022 they were unaware that the filter was required. The bin is used as a backup that holds about two days’ worth of grain in case other equipment fails, according to a recent DNR inspection report.
“They also stated that they were not certain whether the bin vent filter was ever installed or, if it was removed, when the removal occurred,” the order said.
Years before, the company had been given the choice to monitor dust emissions from the bin to ensure it didn’t exceed regulations, or to install the vent filter. The DNR noted it was “highly likely” that emissions from the bin would violate standards for particulate matter, and Siouxland Energy chose the filter option.
The effects of the lack of filter are unclear because of the lack of monitoring, said Julie Duke, a DNR environmental specialist in air quality compliance.
“It can put the public and the environment at risk,” Duke said.
Sioux Center is about two miles east of the plant and has a population of about 8,300.
The DNR fined Siouxland Energy and has required it to install filtration equipment by July 1. The company must also do weekly visual checks for dust emissions from the bin and report to the DNR if dust can be seen.
Jeff Altena, the company’s chief executive, did not immediately respond to a request to comment for this article.
Siouxland Energy has expanded its ethanol production capacity considerably since it began operating in 2001, according to DNR records, and now has a capacity of about 90 million gallons per year.
The company has received rule violation warnings occasionally over that time and another fine early in its operation, DNR records show.
Less than two years into the facility’s operation — when it was producing about 14 million gallons of ethanol per year — the DNR inspected the facility and noted several pieces of equipment with the potential to pollute the air that had no emissions controls, wastewater that was not treated sufficiently before it was discharged into a nearby stream, and other violations.
Over the course of several months in 2002 and 2003, the DNR noted: the stream was milky and malodorous; the facility spilled about 2,600 gallons of ethanol and 1,500 gallons of corn syrup; there were excessive air pollution emissions; and workers failed to adequately check and document the condition of equipment.
The state fined Siouxland Energy $10,000 in late 2003 and rejected requests to reduce the fine. The company suggested $3,000 instead.
“This administrative order was issued for violations of three different environmental programs in the department: air quality, wastewater, and hazardous conditions,” a DNR attorney wrote to the company in 2004. “As such, the department could have issued individual orders for $10,000 each, for a total penalty of $30,000.”
In 2007, the company received a warning from the DNR for starting construction on a production expansion without first obtaining all necessary construction permits, according to the department’s records. That expansion was expected to boost production to about 60 million gallons annually.
In 2017, Siouxland Energy requested to increase its capacity gradually to 90 million gallons per year. It was warned by the DNR that year for exceeding its permitted production capacity.
The company received other warnings between 2008 and 2014 for failing to submit reports, for testing emissions when equipment was operating at partial capacities, and for receiving too much grain.
Exceeding the grain and ethanol production limits can lead to excessive emissions.