Sioux City completes ultraviolet disinfection upgrade at wastewater plant, officials say it removes need for bulk disinfectant chemicals

City staff briefed the council that the wastewater treatment plant's ultraviolet (UV) disinfection system has been completed and accepted by the state, replacing the prior chemical-based disinfection process.

Tom Pingle, utilities and public works director, said the UV system was chosen to reduce ongoing chemical handling and the large chemical costs previously associated with sodium hypochlorite and the quenching chemical sodium bisulfite. "This project was to, 1, replace, our current disinfection system, that is quite costly in the amount of chemicals ... This was a great option to switch over to UV as it uses no chemicals," Pingle said. He noted the system does use electrical energy to create the ultraviolet light.

Pingle credited Journey Construction as the contractor and Black & Veatch as the project engineer, and said the project experienced supply-related delays for electrical components but completed without major problems. He said the system is now closed out with the state of Iowa and is no longer using the previous chemicals before discharge to the Missouri River.

Why it matters: UV disinfection eliminates the need to store, handle and transport hazardous disinfectant chemicals at the plant, reducing safety risks for operators and upstream chemical use and discharge logistics.

What's next: Staff said project closeout procedures are complete and routine operation under the new disinfection method will continue. Payment authorization for contractor work on the UV project was listed among consent/payment resolutions.