“A few times we’ve had some iron and manganese that has come through the treatment plant and has gotten out into the distribution system before we know it’s there,” Marler said.
“We have changed our treatment quite a bit in the last three weeks and have gotten special (Kansas Department of Health and Environment) approval to do some different things,” Marler. “Theoretically, we shouldn’t have any more yellow water.”
Marler said the excess iron and manganese is coming from Marion Reservoir, which is the city’s raw-water source. Some changes made during the recent plant upgrade project have contributed to the color issues.
“The reason we hadn’t had this iron and manganese problem before is because the chlorination process was right at the beginning (of the process), so we could oxide the iron and manganese and it would drop out inside the plant and then we’d never see it.
“Now we’re hitting it with chlorine at the very end, right as it’s going out to town.”
The change in the process was made to comply with regulations. To address the issue, the city has received permission from KDHE to move the chlorination a bit earlier in the process, which should control the color issue.
Marler said a chemical feedback system has been added so that if the chlorine residual drops below a certain point the system will automatically inject more chlorine ahead of that point so the water will be oxidized.
The feedback system includes a phone dialer that will call water department staff—even in the middle of the night—if the chlorine drops below a certain point.
“I am hoping we have enough stuff set up now that we won’t have that problem,” Marler said. “I do get quite a few phone calls (from residents), but I always encourage people to call us and let us know when they do have those problems so we’re aware of it and can take care of it.”
On a different matter, Marler said some residents have been noticing a stronger chlorine odor to their water, but that too should be temporary.
“KDHE recommends that if your system uses combined chlorine, which we do, once a year you should switch to free chlorine,” she said. “Free chlorine doesn’t last as long out in the system, but it is a really strong oxidizer right off the bat.
“Once a year they recommend doing a burning and a flushing of the system,” she added. “So we’ll switch from combined chlorine to free chlorine this time of year for about a week. Then we’ll go out and flush the fire hydrants and overflow the towers to get everything clean.
“Usually, we don’t get a lot of calls when we do that, but this year we have because of the yellow water (issue).”
Marler said the two issues are unrelated, and neither issue compromises the safety of the water for human consumption.
“What you have to do to take care of the aesthetic issues can compromise what you’re trying to do to meet regulations,” she said.