SOUTH SIOUX CITY — Big Ox Energy is facing another notice of violation from the Nebraska Department of Environmental Quality.
The state agency sent the South Sioux City biofuels plant a letter on Thursday, alleging it had failed to control emissions of hydrogen sulfide, properly operate and maintain anaerobic digesters, control dust from leaving the property and submit proper notifications.
It was the third notice of violation issued to Big Ox since mid-June in relation to digester upsets and emissions issues at the facility the past few months.
Big Ox, which converts organic waste from local industries to methane, started battling recycling digester issues in May that sent sludge spilling out the top of digesters at its plant.
Thursday's letter alleged hatches on digesters were "open and venting uncontrolled emissions of hydrogen sulfide" during a July 26 inspection, a violation believed to be ongoing since issues began in May.
The letter said portions of the digesters were not being properly maintained, and dust from site cleanup had become airborne in high quantities and was visible in the air beyond the property line.
In an emailed statement, Big Ox Energy spokesman Kevin Bradley said the company is fully cooperating and communicating daily with the NDEQ.
"Big Ox Energy has made significant progress toward restoring its plant in South Sioux City to normal operations," Bradley said. "A comprehensive clean-up effort will continue until all materials released from the digester are removed and disposed of properly."
As part of the notice of violation, the state is requiring Big Ox to submit a handful of records and a schedule of repairs to the digesters and roof.
Big Ox Energy received its first notice of violation June 20, in regard to the facility's sludge discharges. A second notice on July 23 alleged air quality violations.
The facility and the NDEQ entered into a consent order July 30 that will resolve the first notice of violation and an associated emergency complaint and order. Big Ox has agreed to use measures to cease the discharges at the facility and continue cleanup efforts, repair equipment and decrease the risk of future upsets.
The new violations outlined Thursday are being considered for further enforcement action, which may include an administrative order or penalties up to $10,000 per day per violation.
