MANATEE, Fla. — It took a heavy steel plate, an underwater rover and more than 600 truckloads of sand to finally patch the torn liner at Piney Point and prevent the pond from leaking.
About two months ago, operators discovered a leak in a giant pond that could have caused a massive flood. Since then, crews have worked around the clock to avoid that catastrophe. State officials say the plan is to clean and close the site for good.
The biggest hurdle is getting rid of the 600 million gallons of process water that are still leftover from the former phosphate processing plant. Because the process water was used to run the machinery, it’s high in nutrients that are harmful to the environment.
Industrial waste like process water is supposed to be treated before it enters local waterways, but when the breach was discovered in Piney Point’s largest reservoir, the Florida Department of Environmental Protection gave emergency clearance to dump 215 million gallons into Tampa Bay to prevent a disaster on land.
More than 300 homes in a roughly 1-mile radius were ordered to evacuate the area after engineers learned that the breach could have created a 20-foot wall of water. The evacuation order was lifted after flood models showed that a major flood was no longer likely.
Gov. Ron DeSantis and FDEP Secretary Noah Valenstein have said they plan to hold the company in charge of Piney Point, HRK Holdings, LLC, responsible for the accident but stressed that the current focus is closing the site.
Ever since the initial crisis was averted, engineers have monitored the situation and tried different ways to stop the leak caused by a liner tear near the bottom of the largest Piney Point pond, which once held 480 million gallons of water.
But the process hasn’t been free of hiccups.
About two weeks after Piney Point sounded the alarm, crews used a submersible vehicle to find the source of the leak. They placed a 10-foot square steel plate on the tear to prevent the pond from leaking, but the plate didn’t stay secured and a “low-level flow” continued for several days.
In order to plug the tear beneath that plate, crews added stones below the plate to stabilize it, which “significantly” reduced the flow. Later, a geo-composite material was placed in a 20-foot square on top of the plate and surrounded by more than 16,000 cubic yards of sand to reinforce the plate.
The sand brought in from Mosaic’s Fort Lonesome facility made all the difference, according to HRK’s notes. Before its placement, site operators said they could use a stethoscope to hear an estimated 129 gallons of water per minute rushing underneath the liner.
“As a result of this effort, the flow of concentrated seepage into the onsite lined stormwater system has been minimized,” FDEP wrote in a daily update on May 23.
While the seepage from the pond continued for weeks, none of that contaminated water has left the Piney Point site since April 8 when the discharge into Tampa Bay was turned off. The leak has been contained in stormwater ponds on the site, FDEP said.
FDEP has also contracted innovative water treatment companies to clean the process water at Piney Point. In a recent presentation to county leaders ahead of the leak, Nclear CEO Mike Mies said his technology is capable of removing nitrogen and ammonia from the water, bringing it to marine quality standards.
According to County Administrator Scott Hopes, about 7 million gallons of water had been treated as of May 4. FDEP declined to provide the Bradenton Herald with a more recent update. Despite the state agency’s daily Piney Point updates and several requests for comment, FDEP has been tight-lipped about the specific details of the site’s cleanup progress.
In a May 21 update to FDEP, HRK Holdings site manager Jeff Barath shared that his staff found a series of “critical condition” tears in one of the other Piney Point ponds, which is one of the areas being used to clean and clarify the water. Those rips are thought to have been caused by mechanical equipment.
“HRK identified a total of ten (10) deficiencies in these cells that appear to fully penetrate the liner system,” Barath wrote in an email to an FDEP engineer, noting that he expected to repair the tears within five days.
The tears discovered in that pond’s liner are at least five feet above the water line, according to Barath. It is unclear whether those tears may have impacted the innovative water treatment process.
Piney Point hit another snag the week of May 17 when the engineers were forced to shut down the system that sent up to 100,000 gallons of process water per day into the county’s wastewater treatment system. Barath wrote that a closer inspection of the pipes showed “excessive scaling” that blocked almost 100 percent of the flow.
Barath said he planned to meet with the county officials to discuss options for restarting the wastewater treatment system as soon as possible.
State officials have said they expect the Piney Point closure to cost $200 million. The Florida Legislature approved half of that money earlier this year, and some local leaders predict that it may be enough to clear the site.
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