SOUTH SIOUX CITY -- Big Ox Energy plans to temporarily suspend its biogas production operations in order to make repairs that the company hopes will solve ongoing emissions and odor issues that have led to numerous citations from regulators and complaints from neighbors.
A company spokesman said Friday the South Sioux City plant will stop accepting truckloads of organic waste from roughly two dozen customers by Monday and gradually wind down operations until early May, when methane production will cease.
"We would certainly like to see this facility be successful over the long term. We believe this temporary shutdown will allow us to achieve that," said Kevin Bradley, Big Ox director of business and economic development.
Damaged digesters that have leaked emissions in past months will be emptied and evaluated, then repaired. Bradley said the extent of damages and necessary repairs will determine how long production will be halted. Bradley said the damage has occurred over time since Big Ox began operations in September 2016.
"There has been a series of events that has caused damage since the starting of the facility," he said.
It's possible that some of the more than 30 plant workers will be laid off during the shutdown, Bradley said.
Though inconvenient for Big Ox customers, South Sioux City Mayor Rod Koch said the Wisconsin-based company's decision could help it and the city move forward.
"We want them to operate their plant profitably but also properly in the aspect of the smell and any problems they've been having with smell and spills on their property," Koch said. "I think they're finally getting a grasp on what they're doing out there, and everyone will benefit from that. They're getting this thing cleaned up, and we're very happy about that."
Earlier this month, the Nebraska Department of Environmental Quality cited Big Ox for failing to control emissions after inspectors noticed gases leaking from a damaged anaerobic digester structure.
Bradley said Big Ox's decision to temporarily halt gas production was done voluntarily, and the company will communicate with the NDEQ and the U.S. Environmental Protection Agency while repairing and restarting the facility.
Big Ox, which converts organic waste from local food and beverage manufacturers to methane, has had problems with repeated venting of hydrogen sulfide gas into the atmosphere and solid waste spills, some of which have run off onto neighboring properties. The company also has been cited for storing solid waste on its grounds outside the plant. Bradley said the solid waste stockpile should be removed from its site by June 1.
The NDEQ has issued notices of violation to Big Ox for air quality violations on July 23, Aug. 16 and Nov. 7 in 2018 and storm water and pollutant discharge permit violations on June 20, 2018. A storm water permit violation was sent to Big Ox on Jan. 7.
The EPA also has issued notices of noncompliance, violations, administrative compliance orders or warning letters to the company four times from Oct. 4, 2017, to Feb. 8.
The NDEQ has ordered Big Ox to appear for a May hearing to justify why its state air quality and storm water permits should not be revoked.
Despite its regulatory issues, Big Ox was producing 1,000 decatherms of gas daily, injecting it into an interstate pipeline and selling it to a private customer Bradley declined to name. According to conversion charts, Big Ox was producing enough gas to supply more than 4,000 homes per day.
In addition to its environmental issues, Big Ox has been cited numerous times for violating its wastewater treatment permit with the City of Sioux City.
The plant collects wastewater from other Roth Industrial Park tenants, pretreats it and discharges it to the Sioux City regional plant. Sioux City has fined Big Ox $95,500 for a series of violations, most of them for discharging excessive amounts of suspended solid waste, from June through March.
Big Ox's wastewater permit is up for renewal at the end of April, and Sioux City has yet to renew it.
Bradley said Big Ox will continue to accept and pretreat wastewater and discharge it to Sioux City while the plant's gas production is shut down, though the volume of the discharges will be reduced. The company will continue to discuss its permit renewal with Sioux City, Bradley said.
Since Big Ox began operations, it has been the subject of numerous odor complains from South Sioux City residents living near the plant. A class action lawsuit has been filed against the company claiming that its odors are a nuisance and the result of negligence. A total of 15 homeowners have filed individual lawsuits against the company and South Sioux City, claiming that toxic odors and gases backed up into their homes shortly after the plant began operations, causing health issues and making their homes uninhabitable.
It's hoped that the upcoming plant repairs will alleviate issues at the heart of those complaints.
"The intent of any repairs will certainly address any of the concerns," Bradley said.