Workers at a manure digester in northwest Iowa did not act on signs of a potential leak before thousands of gallons of wastewater poured into nearby waterways, according to documents from the state’s environmental regulator.
In early February, a manure digester owned and operated by Colorado-based biofuel company Gevo. Inc. leaked approximately 376,000 gallons of manure water into creeks near Winding Meadow Dairy, roughly 60 miles north of Sioux City. The spill caused E. coli readings to spike in nearby streams and Rock River.
Last week the Iowa Department of Natural Resources (DNR) fined Iowa dairy farmer Terry Van Maanen $10,000 for the spill, the maximum amount the department can impose. Gevo Inc. has not been fined for the incident.
Van Maanen owns Winding Meadow Dairy, where the digester is located. At the time of the spill, the digester was operating without permission from the state, due to a lack of construction certifications.
Neither Gevo Inc. nor Van Maanen immediately returned a request for comment.
Manure digesters, or anaerobic digesters, break down cow manure through a process called anaerobic digestion. According to the Environmental Protection Agency, the process creates biogas used for electricity, heat, compressed natural gas and vehicle fuel.
According to an administrative order from DNR, warning signs of a leak were not investigated before the spill. Documents show workers noted the fluid level in the digester dropped by five feet when liquid was first added to the digester.
Without any further investigation into the cause, more liquid was added to the digester, according to the findings.
Van Maanen and Gevo Inc. later discovered that improperly sealed control joints likely caused the leak, according to DNR’s findings. The joints have since been repaired.
Devyn Hall, a farming and environmental community organizer with Iowa Citizens for Community Improvement, said DNR’s $10,000 maximum isn't enough. Hall said DNR’s maximum fine is too low and doesn’t do enough to discourage future spills.
"We see this so often with manure spills and factory farms — we have repeat violators, we have massive spills and they don't get the fines that they deserve," Hall said. "Even in this case, $10,000 for the amount spilled doesn't add up."
The amount of manure water spilled from the digester could fill roughly 18 swimming pools.
Iowa Citizens for Community Improvement pressed Iowa Attorney General Tom Miller to pick up the case and levy higher charges against Gevo Inc. and Van Maanen. In certain cases, the attorney general’s office can take on cases referred to the office by the DNR to access higher charges and fines than the DNR’s maximum amount.
Hall said the group sent 350 emails urging DNR and Miller's office to seek further enforcement.
In the end, Miller's office didn't take the case. Even so, Hall said the fine carries meaning. They said it's a sign that pressuring DNR and the attorney general's office worked.
"Getting that news was inspiring," Hall said. "We had a feeling the fine would be much lower, but it turns out the pressure worked. If we have people pressuring the DNR and the attorney general saying 'Hey, we're watching,' then maybe we can get these small wins."
Gevo Inc. owns three manure digesters in northwest Iowa, including the digester at Winding Meadows Dairy. The company recycles biogas from dairy farms' manure and processes it into renewable natural gas to be sold in California, touting the projects as environmentally friendly.
According to a company filing with the Securities and Exchange Commission in June, two other incidents at Gevo Inc. owned manure digesters in Northwestern Iowa occurred in April. Both incidents resulted in the “accidental discharge of very small amounts of water and manure into the environment.”
The filing states Iowa DNR may file further financial sanctions against Gevo Inc. concerning the spills but notes the fees wouldn't greatly impact the company financially.
Of the 376,000 gallons of manure water leaked into the nearby creeks in early February, DNR reported Gevo contractors removed 48,525 gallons of slurry water, a mixture of sediment and water, from the area deposited into a nearby lagoon.
In the days following the spill, E. coli levels in downstream creeks and the nearby Rock River spiked.
E. coli is a bacteria found in bodies of water exposed to human or animal waste. When ingested, the bacteria can cause mild to life-threatening symptoms in humans.
The investigation found that E. coli levels in Lizard Creek, where most of the manure water leaked into, were roughly nine times higher two days after the leak.
Mud Creek's E. coli readings also increased in the days following the leak, exceeding Iowa DNR's surface water standards. Lizard Creek does not have a listed average, according to the state.
The two creeks feed to Rock River, where E. coli levels steadily increased in the days following the leak but did not exceed surface water standards.
The E. coli levels in all three bodies of water steadily trailed off in the weeks following the leak.
Jacob Simonsen, a wastewater specialist with DNR, said the winter weather and frozen creeks near the digester helped contain some of the waste.
"You never want to see anything like this happen but it wasn't as potent of a release as it could have been," Simonsen said.
This story comes from the Midwest Newsroom, an investigative journalism collaboration including IPR, KCUR 89.3, Nebraska Public Media News, St. Louis Public Radio and NPR.
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