BLOOMINGTON, Ind. — The City of Bloomington is working on solutions as organic compounds impact the taste of water.
City of Bloomington Utilities says the organic compound is methylisoborneol (MIB). While it is not harmful to human health, this compound can cause a musty taste in the water.
Some people can taste the impact of this compound as little as 20-30 parts per trillion(ppt). The latest data from the city shows its presence has skyrocketed in the last week to 288,000 ppt.
“These are the highest MIB numbers we’ve seen,” said Tyler Steury with City of Bloomington Utilitites.
Even after the city’s water filtration process, which includes adding powdered activated carbon, copper sulfate, and sodium permanganate during treatment, the water contains 180 ng/l of MIB, or 180,000 ppt.
While the city usually recommends filling a pitcher or jug with water and adding lemon or fruit to disguise the taste, for some this will not work. Others may taste it directly from their faucet but not after using a basic pitcher filter.
The issue comes as the area sees continued hot and dry weather. The city says between high lake temperatures and the low lake level in Monroe Lake, it is making ideal conditions for algae to thrive. This algae produces MIB and geosmin, which creates an earthy odor.
“This is an ongoing issue for communities around the world using surface water and particularly lakes as their water source,” said Steury.
The city is meeting with engineering firms, consultants and equipment vendors to discuss how to fix the issue in the long term. One short-term idea they are considering is aerating the water column at their raw water intake tower. This may help alleviate the taste and odor issues.
The city says a longer-term solution includes refurbishing the filtration system. They are in the beginning stages of this, which isn’t expected to be completed until 2023.
City of Bloomington Utilities continues to test the water for many different quality parameters. The city expects as the weather cools, the algae will return to normal levels.
For now, the water continues to be safe to drink, even if it tastes a bit off.