Oconomowoc utility staff brief council on chlorine, fluoride and orthophosphate use and monitoring

City of Oconomowoc utility staff on Tuesday briefed the common council on the chemicals the utility adds to drinking water, how they monitor doses and the safety measures they use.

Scott Osborne, the water superintendent, told the council the utility doses gas chlorine for disinfection, fluoride to help prevent tooth decay and a blended orthophosphate product (AquaMag) for corrosion control and iron sequestration. “We dose at our 3 spots there between 1.5 and 3.3 milligrams per liter,” Osborne said of chlorine, and he said the utility follows current fluoride dosing recommendations of 0.7 milligrams per liter. He described orthophosphate dosing in the range the utility uses and said orthophosphate was added in the mid-1990s after a Wisconsin Department of Natural Resources corrosion-control study recommended a sequestering chemical.

The council was given details about daily and periodic monitoring. Osborne said crews visit each chemical feed site every day, record pumped volumes and chemical consumption, and enter data into spreadsheets used to check that dosages stay within…