Coconut-based carbon could improve Bloomington’s water flavor

Bloomington, Indiana – On October 29, the City of Bloomington Utilities declared that it was now treating the city’s drinking water with a coconut-based solution to address issues with taste and odor.

After a lengthy and meticulous investigation by local water treatment operators to discover a solution for the water’s taste and odor, city utilities started the treatment late this summer, according to Bloomington Water Quality Coordinator Justin Meschter.

This issue recurs seasonally and is associated with late summer algal blooms in Monroe Lake, the city’s water supply.

Drew Kelley, a freshman at IU, stated, “It has a slightly metallic, bland taste to it, which is always a little noticeable.”

Bloomington native Kelley claimed that although he has been accustomed to the taste issues, several of his classmates were surprised.

“Everyone I’ve spoken to at college who comes from other places has serious issues with the water in Bloomington,” Kelley stated. “But even though it’s not the best, you kind of get used to it over time as a Bloomington native.”

While investigating possible remedies for this problem this summer, city utilities found that a powdered activated carbon (PAC) derived from coconuts would work well.

This treatment, according to Meschter, is a variant on an established technique. In the past, PAC derived from a combination of sources was used to filter the city’s water treatment facility. More of that carbon is now coming from coconut husks.

According to Meschter, the city’s water treatment facilities address organic pollutants in the water by adding PAC to its treatment basins. In late summer, when Monroe Lake’s algae life cycle generates the organic chemicals that cause complaints of foul-tasting water, Bloomington Utilities uses more PAC. Through the removal of organic pollutants, particularly those produced by algae, this increasing use of PAC helps to reduce that issue.

Testing conducted this spring revealed that PAC made from coconut husks may be much more potent than the conventional combination.

“We had to conduct the investigation and examine whether we could alter the carbon we use, the rate at which we mix it in our rapid mixers or the rate at which we feed the carbon,” Meschter stated. We investigated a wide range of minor adjustments. We conducted additional research on this one after determining it was worthwhile to investigate further.

The results of the coconut-based PAC were favorable.

“This coconut-based carbon has been demonstrated in water treatment to be slightly more effective at eliminating organic matter from taste and odor contaminants in the water,” Meschter added.

According to Meschter, there is no risk to human health from taste and odor issues. The use of coconut-based PAC does not introduce any coconut pollutants to Bloomington’s water, despite some locals’ worries that it would endanger those who are allergic to coconuts, he added.

“The main source of [the coconut-based PAC] is simply burning or incinerating coconut husks, and part of that is that there are no coconut proteins left in the coconut husks after they have been burned,” Meschter explained. “It’s just pure carbon that comes from the husk of the coconut.”
Meschter added that the PAC is filtered out before it enters the water supply because it is insoluble in water.