An Iowa cow manure recycler that leaked thousands of gallons of wastewater last month into creeks flowing into a tributary of the Big Sioux River was operating without the state's permission.
The Iowa Department of Natural Resources (DNR) began investigating a leak of more than 376,000 gallons of manure water on Monday, Feb. 7, at Colorado-based Gevo Inc.'s manure digester in Rock Valley.
The digester is one of three in Lyon and Sioux counties being built by the company. Gevo hopes to recycle biogas from nearby dairy farm manure and process it into renewable natural gas to be sold in California. The company has touted the project as environmentally friendly.
Gevo didn’t have approval from the state to begin pumping manure through the digester when it leaked wastewater into the then-frozen Lizard Creek and Mud Creek, according to documents obtained from DNR.
A letter detailing Gevo’s violation stated the company failed to submit construction certifications for their digester.
Gevo Inc. did not respond to requests for comment on the leak. In a Feb. 24 filing with the Securities and Exchange Commission, Gevo reported that cleanup and mitigation work to minimize the impact of the discharge continues. The filing also stated Gevo could face a fine for the leak but the company does not expect fines to exceed $300,000.
DNR ordered Gevo to provide construction certifications, documentation of the source of the leak and the repairs made to the digester, according to a letter outlining the violations.
Jacob Simonsen, a wastewater specialist with DNR, said it's not clear if Gevo’s violation of construction permits played a role in the leak, but said the facility operated without permission from the state and could face legal action.
Simonsen said he could not comment on what consequences Gevo may face for the leak.
Of the 376,000 gallons of manure water leaked into the nearby creeks, 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.
Simonsen said while DNR remains in the early stages of monitoring the effects of the leak, the cold weather and frozen creeks near the digester helped contain some of the waste.
Simonsen added the risk to public health is also lower since it’s unlikely people are swimming nearby creeks and rivers due to the cold.
“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, adding that Gevo reported and stopped the leak quickly after discovering it.
Simonsen said it was difficult to determine how far the manure water traveled but is confident the wastewater reached Rock River.
Documents from the state investigation show E. coli levels spiked in the creeks and nearby Rock River following the leak.
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.
E. coli levels in Lizard Creek were roughly nine times higher two days after the leak, the investigation found. 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 standard, according to the state.
On Rock River, which the two creeks feed to, E. coli levels steadily increased in the days following the leak but did not exceed surface water standards.
The level of E. coli in all three bodies of water steadily trailed off in the weeks following the leak.
Gevo touts its digesters as an environmentally friendly way to recycle animal manure to produce renewable natural gas. The company began developing plans for the digesters in Iowa in 2019, according to its website.
The start-up plans to use manure from over 20,000 dairy cows to produce the gas through their digesters, which they then sell in California.
Gevo financed the digesters through $68 million of Solid Waste Facility Revenue Bonds issued by the Iowa Finance Authority. The authority awards the tax-exempt bonds to private companies that have “substantial public benefits.”
According to Gevo filings, the company’s digesters will compress methane, carbon dioxide and hydrogen sulfide before moving the biogas to a second facility through several miles of underground piping. From there, the biogas is refined into renewable natural gas and sent to an interstate pipeline.
In recent SEC filings, the company reported it has suffered nearly $150 million in net losses over the past three years and currently has an accumulated deficit of $557.4 million.
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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