City of Bloomington Utilities announced Oct. 29 that it is now using a coconut-based treatment to address taste and odor concerns with the city’s drinking water.
City utilities began the treatment late this summer as a result of what Bloomington Water Quality Coordinator Justin Meschter described as a long, careful research process by local water treatment operators to find a solution for the water’s taste and odor.
This problem is seasonally recurring and coincides with the late summer algae blooms in the city’s water source, Monroe Lake.
“It’s got just a bit of like metallic, bland taste to it, which is always a little noticeable,” IU freshman Drew Kelley said.
Kelley, who grew up in Bloomington, said that while he has gotten used to the taste problems, it came as a shock to some of his classmates.
“All these people I’ve talked to at college who come from other places have severe problems with the Bloomington water,” Kelley said. “But as a Bloomington native you kind of get used to it over time, even if it’s not the best.”
This summer, while researching potential solutions to this issue, city utilities discovered a coconut-based form of powdered activated carbon (PAC) could be an effective treatment.
Meschter said this treatment is a variation on an existing method. Previously, the city’s water treatment plant filtered with PAC made from a blend of sources. Now it’s sourcing more of that carbon from coconut husks.
Meschter said the city’s water treatment plants add PAC to their treatment basins to treat organic contaminants in the water. Bloomington Utilities increases its usage of PAC in late summer, when the life cycle of algae in Monroe Lake produces the organic compounds responsible for reports of foul-tasting water. This increased usage of PAC mitigates that problem by removing organic contaminants, including those produced by algae.
Results from testing this spring found that PAC sourced from coconut husks could be even more effective than the standard blend.
“We had to do the research, look into, you know, can we change the carbon we’re using, can we change the mixing rate in our rapid mixers, can we change the rate at which we’re feeding the carbon,” Meschter said. “There’s a lot of different small changes we looked into. This was one we decided was worth looking into further, so we did more studies on it."
The coconut-based PAC produced positive results.
“It’s been shown in water treatment that this coconut-based carbon is a little better at removing organic matter in taste and odor contaminants in the water,” Meschter said.
Meschter said the taste and odor problems are not a threat to human health. While some residents expressed concerns that this method could pose a risk to people with coconut allergies, the use of coconut-based PAC does not introduce any coconut contaminants to Bloomington’s water, he said.
“[The coconut-based PAC] is basically just derived from incinerating or burning coconut husks, and part of that is there’s no coconut proteins that are left in the coconut husks after it’s been incinerated,” Meschter said. “It’s just a pure form of carbon derived from the coconut husk.”
Meschter also said the PAC, which does not dissolve in water, is filtered out before it reaches the water supply.
Residents can find more information at the CBU website, which also reports on the city’s water quality. Customers can submit non-emergency utility concerns here.
