“Water tastes fishy and like it’s straight out of a creek.” That’s from an Aug. 29, 2022 complaint logged in Bloomington’s uReport system.
The complaint is one of at least 14 such reports filed since Aug. 27.
It’s the second late summer in a row that Bloomington’s water has started tasting and smelling bad. The cause is elevated levels of blue-green algae in Lake Monroe, which is Bloomington’s drinking water source.
The current bad taste and odor is not a public health risk, according to city of Bloomington utilities.
The fact of increased blue-green algae levels is confirmed by Indiana’s department of environmental management (IDEM), which routinely samples levels in Lake Monroe. Currently the Paynetown and Fairfax state recreation area beaches are on an “advisory alert” level. That’s the second of four alert levels—low risk, advisory, caution, and closed.
The foul-tasting water was in years past a problem that recurred every year in late summer—fueled by dry, warm weather, which makes Lake Monroe ripe for increased blue-green algae concentrations.
But in 2017, city of Bloomington utilities (CBU) started adding powdered activated carbon (PAC) to the city’s drinking water. The reason CBU started adding PAC to the water was not to help with the taste and odor problem. The point of adding PAC is to help prevent the formation of disinfection by-products.
But the PAC also has the welcome side-effect of helping to remove naturally-occurring compounds called Geosmin and Methyl-Isoborneol (MIB), which are associated with elevated blue-green algae concentrations. It’s those compounds that cause the bad taste and odor.
On Tuesday evening, CBU director Vic Kelson told Bloomington’s city council that the maximum amount of PAC is being fed into the water treatment plant: “Right now, we are maxed out on feeding our activated carbon to the plant.” That means the bad taste and odor will likely persist for another few weeks, Kelson said. “Hopefully we’ll get some cooler weather, and some rain would sure help,” he said.
Kelson was speaking to the council in the context of the proposed 2023 city budget.
After enjoying four years free of late summer complaints, this makes two seasons in a row for bad-tasting Bloomington water. As Kelson put it, “One time is a fluke. Two times is a pattern.”
Kelson said because of the pattern, he has asked CBU staff to look into the possibility for pre-treatment of the vertical water column near the intake pipe.
That’s not something CBU could implement on its own. Kelson said if the water is going to be pretreated before entering the plant, CBU will have to work with the US Army Corps of Engineers and Indiana’s DNR, which manage the lake.