Activated carbon protects taste, smell of Grand Rapids drinking water

By: Deborah Johnson Wood

In an effort to maintain superior taste and smell in its drinking water supply, the Grand Rapids Water Department is treating the city water with activated carbon before the water is affected by any musty odor and taste caused by algae growing in Lake Michigan. The algae particles appear every summer as soon as Lake Michigan warms up and, while harmless, they just don’t taste or smell good.

“We want our customers to like the way our water taste and smells,” says Joellen Thompson, water system manager. “So beginning next week we’ll add activated carbon in small doses before the problem occurs. As the temperature goes up, we’ll add more, and hopefully we won’t have any taste and odor issues.”

Activated carbon is a powder that attaches to the algae particles, becomes heavy and drifts down to the water treatment facility’s sedimentation basins where it is filtered out, taking the mustiness with it.

The city will add the carbon at the rate of two milligrams per liter, going up as high as eight milligrams per liter, as needed. The cost will run about $121,000 to treat 5.5 billion gallons over the summer.

“Every city around here that gets drinking water from Lake Michigan had the problem last year,” Thompson notes. “The problem seems to be increasing and one of the reasons is the increase of quagga and zebra mussels, both invasive species. They eat microorganisms in the water and make it clearer, sunshine penetrates it, the water warms and the algae grow more prolifically.”

Other ways to treat the problem are by using ultraviolet light to kill the algae particles, or by treating the water with ozone. Both processes would require construction of expensive new facilities.

Source: Joellen Thompson, Grand Rapids Water Department

Deborah Johnson Wood is the development news editor for Rapid Growth Media. She can be contacted at [email protected].