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Progress is made on closing the troubled Florida phosphate plant stacks

Daylina Miller
WUSF Public Media
Herb Donica atop the gypsum stack when digging began on the deep-well injection site in April.

There has been a lot of progress in the long-awaited closure of the troubled Piney Point phosphate plant along Tampa Bay. One of the four ponds on top of the site is could be empty by the end of this week.

Herb Donica can see the end of Piney Point — just give it a little more time, he said. Donica is the court-appointed receiver in charge of closing the old phosphate gypsum stacks, which suffered a tear in 2021 that resulted in the release of more than 200 million gallons of polluted water into Tampa Bay.

In April, an injection well was dug that will place much of that water deep below the drinking water aquifer. By the end of this week, Donica said they will have disposed of 70 million gallons.

Heavy algae growth from recent rains and summer sun is slowing things down a bit. But Donica said they're still ahead of schedule.

"We're pretty much clicking along every day at 700,000 gallons a day on a well that's designed for a million gallons a day," he said. "But we've throttled it down to be able to handle the algae issue carefully and safely."

Positioned to handle potential hurricanes

Donica says that puts Piney Point in a position to withstand any heavy rains from the upcoming hurricane season.

"We will see no emergencies with Piney Point during the hurricane season because we have over 50 inches of freeboard," he said. "That means we could take on a lot of rain, a lot of storm water could come into the system and would not have an effect where increase the sidewall pressure, such to endanger the community.

"So we're very happy and actually very proud of our efforts and (Manatee) county's efforts to work with us to get to that point where we've we've made it safe. That has allowed us to concentrate on wrapping up the closure of the first pond."

READ MORE: Pollution from Florida phosphate plant spread even farther than thought, new study shows

He said they have published a request for proposals to dredge about 700,000 cubic yards of silt and sediment in the pond that is being emptied. A dredging company has to siphon the final three to four feet of sludge so the stack can be closed. Donica said the bids are now coming in and he hopes the project will begin this fall.

"And then we're going to use geotextile bags to store that slurry end. And what that means is the dredge company will pump that sediment in a wet mixture, a slurry that will go up the hill into a giant fabric tube," Donica said. "But the tube is a mesh, so it retains the sediment and the polymer allows it to clump — and to stay in the tube so the water comes back out. And then we dispose of the water."

Complete closure more than a year out

He said polluted water from the most-contaminated of the four ponds at the site cannot be sent down the injection well until a pre-treatment plant is online this fall. He said that is somewhat behind schedule because of supply chain issues.

Donica estimated they're likely a year and a half from having the entire site closed. The stacks will then be covered with a thick sheet, with two inches of dirt and grass above that.

Gov. Ron DeSantis ordered the site be closed after the last spill. So far, the state has spent about $185 million toward the project.

Environmentalists have opposed the deep well injection, which places the contaminated water beneath the drinking water aquifer. They say there's no way to determine if a toxic plume moves underground or migrates upward through the confining layer between the upper and lower aquifers.

 A pond surrounded by land.
Center for Biological Diversity Image
Piney Point south gypstack

Copyright 2023 WUSF 89.7. To see more, visit WUSF 89.7.

Steve Newborn is WUSF's assistant news director as well as a reporter and producer at WUSF covering environmental issues and politics in the Tampa Bay area.
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