The city of Superior is looking to eliminate nearly 11 tons of chlorine from its wastewater treatment process.
The council approved a proposal Tuesday by Strand Associates to provide preliminary engineering for a system using ultraviolet disinfection instead of chlorine.
The current disinfection process creates potential safety hazards for workers and citizens, said John Shamoa, operations manager at the Superior Wastewater Treatment Plant. The process also results in chlorine released into the Lake Superior watershed, he said.
By going to ultraviolet radiation treatment, Shamoa said the city would eliminate the need for elemental chlorine.
"We might still need to use, occasionally, a strong bleach solution in our operations, but that would be much safer than using the liquid or gaseous chlorine."
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Ultraviolet radiation works by altering bacteria at a genetic level, "deactivating them" so they can't multiply, Shamoa said.
The system works with phototubes; the water runs through them and is treated with ultraviolet radiation, said Dan Romans, environmental services administrator for the city.
Funding for the engineering project will be paid through a Section 154 grant, a federal grant program created by Rep. Dave Obey, D-Wis., to provide funding for infrastructure projects in the four northernmost counties of Wisconsin to protect the Lake Superior watershed.
