Wisconsin Cheese Group must pay $237,500 and serve one year of probation after pleading guilty to violating the federal Clean Water Act, following a scheme of untreated wastewater discharges that overwhelmed a small village's sewer system and, at one point, turned incoming sewage a sickly milky-green color. U.S. Magistrate Judge Anita M. Boor handed down the sentence on August 13 in the Western District of Wisconsin, calling the Monroe-based company a “neighborhood polluter” whose violations were entirely avoidable with better planning as production ramped up.
According to the Milwaukee Journal Sentinel, Wisconsin Cheese Group released untreated wastewater from its plant into the municipal sewer on 19 separate days between June 6 and November 5, 2022, as it ramped up production at its Monticello plant. Per Assistant U.S. Attorney Megan Stelljes, who prosecuted the case out of Madison, the company exceeded the biological oxygen demand limit in its discharge permit by more than 1,500% on multiple occasions. U.S. Attorney Chadwick M. Elgersma said the company lacked specific controls to ensure compliance with its permit at the time of the discharges, though he noted it did not fail to train employees on wastewater management.
Sewage Plant Overwhelmed, Odor and Discoloration Reported
The damage traces back to the physical chemistry of dairy waste. Scientific studies cited by MDPI show that raw cheese whey wastewater carries a biological oxygen demand between 30,000 and 60,000 milligrams per liter — roughly 150 to 300 times higher than ordinary municipal sewage — which can rapidly deplete dissolved oxygen and overwhelm standard biological treatment systems. Allison Landsman, special agent in charge of the Environmental Protection Agency's criminal enforcement program in Wisconsin, said the untreated industrial discharges disrupted the publicly owned sewer system on multiple occasions.
That disruption played out in vivid detail on the ground in Monticello. As reported by The Post Messenger Recorder, the June 2022 discharges involved high-sugar whey permeate that killed off the beneficial bacteria the village's wastewater plant relied on to function, causing incoming sewage to turn a milky-green color and give off a foul odor when public works staff discovered the problem. The same outlet reported that in September 2022, a Monticello resident told local officials and state regulators that the company had discharged sludge into a storm drain on his property, leaving behind a foul-smelling rusty film that sickened his dog and killed surrounding wildlife.
Village Employees Faced Personal Fines Up to $50,000 a Day
The fallout wasn't limited to the company. The Post Messenger Recorder's report on the Village Board's discussions noted that by October 2022, Monticello public works officials warned trustees that municipal operators faced potential personal criminal liability or daily fines up to $50,000, while the village itself risked fines exceeding $25,000 per day from state regulators over permit violations caused by the cheese plant's discharges. That kind of exposure for a small municipal government underscores how one industrial user's waste stream can put local taxpayers and employees on the hook for problems they didn't create.
The investigation itself briefly stirred a different kind of local anxiety. New Glarus 360 reported that when federal environmental agents originally executed search warrants at the Monticello plant in 2022, federal officials had to publicly reassure residents that the multi-agency operation was an environmental probe rather than an immigration raid.
Company Ownership and the Legal Standard at Play
Wisconsin Cheese Group Holding LLC drew a private equity investment from Centre Partners in October 2019, backing its production of Hispanic and Caribbean cheeses and dairy products sold under brands including La Morenita, El Viajero, and Reynaldo's, according to a Centre Partners announcement. The company pleaded guilty to the Clean Water Act violation on June 4.
Under Section 307 of the Clean Water Act and federal pretreatment regulations found in 40 CFR Part 403, industrial facilities discharging into publicly owned treatment works are strictly prohibited from releasing pollutants that cause interference or pass-through in municipal treatment systems, according to legal standards laid out by environmental regulators. The case was investigated by the EPA's Criminal Investigation Division and prosecuted by Stelljes, the Journal Sentinel reported.
Wisconsin Cheese Group isn't the only dairy operator to draw scrutiny in the state. In a separate 2024 enforcement action, the Wisconsin Department of Justice assessed $209,641 in penalties against Mlsna Dairy Supply, Inc. for wastewater permit violations at a Sparta operation, a case flagged by New Glarus 360 as part of a broader pattern of regulatory attention on dairy waste across Wisconsin.
What Comes Next for the Monticello Plant
As part of its sentence, Wisconsin Cheese Group must make improvements to its Monroe facility and work more closely with the Wisconsin Department of Natural Resources on future permitting issues. During sentencing, per the Department of Justice, Judge Boor also faulted the company's initial lackluster response to early violations, which allowed the illegal discharges to continue for months before it began cooperating with federal investigators. It remains unclear exactly what long-term infrastructure upgrades will be required at the Monticello facility or whether Monticello's municipal sewer system has been fully shielded against future industrial overloads.
