Another City of Carroll construction project has made great strides in recent weeks, this one at the wastewater treatment plant. Walls have gone up and the roof has been started on the new disinfection building. This project is a means for the city to comply with their Iowa Department of Natural Resources (DNR) operating permit. The council has been preparing for this change to the disinfection requirements, which will have wastewater being treated with Ultra Violet (UV) light before it exits the plant.