HEGEWISCH — Chicago’s rivers have a murky reputation, filled as they have been for more than a century with everything from cattle carcasses to industrial runoff.
But it’s not as if the region hasn’t tried to clean up its act. We’ve long filtered out raw sludge from the sewage and storm overflow systems before sending cleaned and treated water back into the Chicago and Calumet Rivers.
But starting Friday, the Metropolitan Water Reclamation District will also disinfect water passing through its Southeast Side plant, effectively bleaching out harmful bacteria too small to be caught by other forms of filtration.
"This disinfection facility now brings Chicago into the civilized world when it comes to the treatment of sewage,” said U.S. Sen. Dick Durbin at a press conference Friday. "We were the last major city in the United States to put in a disinfection facility.”
Water coming through the Calumet Water Reclamation Plant will now pass through a maze-like concrete contact basin. The winding path allows time for added chlorine to kill off E. coli and other harmful pathogens. Then the water will be de-chlorinated before it empties into the nearby Little Calumet River.
"It’s the final polishing step,” MWRD Executive Director David St. Pierre said. "It’s coming in really clean but it’s not disinfected. So this kills all the bacteria and then it’s discharged to the waterway."
The Calumet facility can treat 480 million gallons of water per day, enough to fill every floor of Willis Tower. One million people live within the plant’s 300-mile South Side and south suburban service area.
"No one likes to talk about sewage,” Durbin said. "But an awful lot of people want to talk about rivers and they want to know if those rivers are clean. They want to know if it’s safe to go boating and what happens if my little boy falls out of the boat? Do I have to worry about that water?"
Disinfecting water flowing into the Little Calumet will now protect those boaters and other recreational users, who might be at risk if they did fall into the water, with say, a cut on their elbow. But the $37.3 million disinfection facility is also a key part of ongoing and efforts to clean all of Chicago’s waterways.
MWRD is still working to complete the Tunnel and Reservoir Plan — better known as the “Deep Tunnel” system — a massive network of storm overflow tunnels and reservoirs meant to keep untreated sewage from entering the rivers and Lake Michigan.
Treated water flowing into the Chicago River is not currently disinfected. That will change when a second disinfection facility at the O’Brien Water Reclamation Plant in Skokie comes online in 2016.
“We’re used to protecting Lake Michigan — it’s a source of drinking water,” said Margaret Frisbie, executive director of Friends of the Chicago River. "The conversation about protecting the river is new in environmental terms. This stuff moves in glacial time."
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