Florida

Florida county brings in bacteria to suck up stinky parts in drinking water

Water from Lake Manatee flows from the gates of the dam into the spillway at the Manatee County Water Treatment Plant. Officials at the plant have developed a new way to treat water for taste and odor using carbon granules and naturally occurring bacteria.
Water from Lake Manatee flows from the gates of the dam into the spillway at the Manatee County Water Treatment Plant. Officials at the plant have developed a new way to treat water for taste and odor using carbon granules and naturally occurring bacteria. Bradenton Herald

The musty, dirt-like smell that often comes out of the faucet may soon disappear from Manatee County's water supply.

Next year, the county breaks ground on a $20 million project at its Lake Manatee water treatment plant that will put some of nature's smallest creatures to work cleaning the water more than 350,000 people drink.

It's a move expected to make for a more enjoyable glass of water from the kitchen faucet and is expected to save water customers money in the long run. The plant project will also be a feather in the county's cap, since the new cleaning system is designed from original research done by water department employees.

When complete in 2017 or 2018, water headed for homes and businesses will be treated by trillions of hungry bacteria that like to eat the stinky byproducts of blue green algae common in surface water. They will replace a system dependent on using about $600,000 of carbon powder every year as a filter.

The bacteria are expected to do a better clean up job, particular during algae bloom periods that tend to overwhelm the system, said Bruce MacLeod, supervisor at the treatment plant at the Lake Manatee reservoir.

MacLeod and his staff have been doing their research for about five years. To confirm that the bacteria-based system would work, they built a miniature version.

"Unfortunately people are very, very sensitive to these," MacLeod said of the algae byproducts. "From the work we've done on this small scale, we are designing a full-scale replica of that to address these earthy, musty compounds."

Last week, the Manatee County Planning Commission approved a general development plan for the 137-acre facility. It includes new sediment settling ponds for water drawn from the lake, a biological filter building, a chemical feed building and several purpose-built water tanks.

Since about two-thirds of the 24 million gallons the county pumps every day is out of the lake, the sun-loving algae has long been a persistent foe.

"It's an issue that has been there since the lake was formed," said Mark Simpson, manager of the county's water division.

Simpson and MacLeod know stinky water. While researching the new water treatment method, they grew their own, concentrated algae in the lab. The byproduct it produced was a lot stronger than they expected.

"I'd go home and it was in my shirt and my hair," McLeod said.

But with the help of the bacteria, it won't be in the water. In every test they've performed, the little critters pull the stinky stuff out of the water in minutes.

The county's drinking water is drawn from the lake and a set of wells. End users include residents of unincorporated Manatee County, Palmetto and some Sarasota County residents. Bradenton has its own water supply, drawn largely from the Braden River.

Simpson said the choice to use bacteria instead of powder is financially sustainable long term. Savings from not buying carbon powder are expected to pay for the new system and its infrastructure within 15 years. Savings after that could be passed to rate payers.

The treatment plant is also including possible future projects in its development plan that would address Manatee County's growing population. On the boards are plans for an additional sludge pond and other facilities that will allow the plant to treat more water for a growing customer base.

The plant currently pumps an average of 37 million gallons per day. Its maximum capacity is 84 million gallons.

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