Josie Taylor | January 10, 2022
According to a state lawsuit that was filed against Sioux City Friday, the city has not been properly treating its wastewater. This has ensured that excessive amounts of bacteria and treatment chemicals were expelled into the Missouri River. Iowa Attorney General, Tom Miller, says that they potentially endangered human lives and wildlife and were fraudulent about it. Miller’s office is litigating the issue on behalf of the Iowa Department of Natural Resources, which oversees treatment plants in the state.
Problems at Sioux City’s wastewater treatment plant have persisted for about a decade after a new disinfectant process began in 2011, the lawsuit claims. In 2012, an engineering firm found that large amounts of wastewater from industrial sites were interfering with chlorine, the plant used to eliminate biological contaminants such as E. coli bacteria. The firm concluded the treatment plant could not adequately disinfect the wastewater
For the following two years, workers at the plant tinkered tests of the wastewater to conceal the problem from the DNR. This led to the federal prosecution of the plant’s former superintendent and a shift supervisor for Clean Water Act violations.
On typical days, the plant was using liquid chlorine at a rate of about 2.5 gallons per hour to kill bacteria, but on testing days it used between 70 and 120 gallons per hour to pass the test, U.S. Attorney Sean Berry said. Staff then reduced the flow of chlorine before testing the treated wastewater for the chemical, which is also regulated by the state.
The plant has continued to use excess amounts of chlorine and ammonia that reaches the river, according to the lawsuit. The lawsuit seeks fines of up to $5,000 per day for the violations and a court order for the city to comply with DNR regulations.