An upgrade to St. Joseph’s wastewater treatment plant forced that city on Tuesday to temporarily let raw sewage flow into the Missouri River and downstream toward the Kansas City area.
The Kansas City water department doesn’t expect the sewage release to foul Kansas City’s drinking water or to put a burden on its treatment facilities.
“By the time it travels 50-plus miles down the Missouri River, any wastewater from St. Joseph is only a small fraction of the amount of water that passes by KC Water’s intake station,” said Brooke Givens, spokeswoman for Kansas City Water Services.
She said the city’s water department anticipates normal treatment levels without a change in quality of water delivered to Kansas City taps. “We will continue with our regular testing, and we will be keeping a close eye on any indicators that would show any increased levels of pollution,” Givens said.
St. Joseph officials characterized the release of sewage as part of a plan to attack brewing problems in its sewage treatment capabilities to avoid a future uncontrolled spill.
“We’re doing this for 24 to 48 hours now to prevent it being down for months,” said Andrew Clements, the city’s assistant director of public works.
The problems stem from an 18-inch-wide metal pipe and the gate, or valve, that shuts it off from the Missouri River. The work comes in conjunction with the replacement and upgrade of a grit box designed to sift out rocks and sand at the St. Joseph plant.
Grit in the pipe had built up, solidifying like concrete and making the valve dysfunctional. The failure of that valve could eventually have been “catastrophic,” Clements said, leading to a difficult-to-control accidental spill into the river.
On Tuesday morning, crews unbolted flanges on the pipe, action that released untreated sanitary sewage and stormwater from about a third to a half of St. Joseph into the Missouri about 6:30 a.m. It flowed from the pipe at a rate of about 8 million gallons a day.
The city expected the work to replace the gate and the grit box — work that had been plotted out in detail since January — to last 24 to 48 hours. By midafternoon Tuesday, Clements said, it appeared the work might be completed in less than 24 hours.
“Although with Murphy’s Law” — the idea that anything that can go wrong, will — “I don’t want to jinx it,” he said.
Clements said the plan to make the fix was timed when the river was relatively high with spring rains and greater releases from upstream dams. He said that way the sewage, already mixed with local storm runoff, would have the most dilution possible in the waterway.
The work comes as part of a $56 million upgrade to the wastewater treatment facilities in St. Joseph. When done, Clements said, it will better control ammonia levels in the water and bring phosphorous and nitrogen levels below those of any other plant in the state.