Longboat Key awaits FDEP feedback for pipeline reassessment

Longboat Key leaders are working with state regulators on a series of planned inspections of the town’s sewage link to the mainland following the June 2020 pipeline break and spill of millions of gallons of effluent in Manatee County.

The town is waiting for feedback from the Florida Department of  Environmental Protection on the inspection plans and will proceed with the 10-month project once given the go-ahead. 

The town is proposing a two-step inspection, beginning with a remote-controlled device that's inserted into the sewage flow on the Longboat Key side and examines the pipeline on its voyage to the Manatee County treatment plant. Following the examination, data will be compared to a similar inspection done in 2016. 

“As it’s traversing the pipeline, it identifies areas where there may be gas pockets or other anomalies,” Public Works Director Isaac Brownman said, adding accumulations of potentially corrosive hydrogen sulfide would be cause for further study.

“It’s important just to note if it’s occurring,” Brownman said. “It doesn’t necessarily mean the pipe is corroding in that location.”

The pipeline will also be inspected for external corrosion. 

Beyond that, divers could be employed to visually inspect or perform other methods of inspection. 

“The divers (would) go down and do a physical observation of the exterior walls of the pipe,” Brownman said. “They will take pictures, but the real key element that the divers will provide is they will do something called ultrasonic thickness testing.”

The town plans to reassess the pipe every three to five years. 

Brownman said the cost of this portion of the reassessment is $182,087.26, which has been budgeted.

In July, the state approved a package of environmental projects to comply with a consent order connected with the spill. The projects include installing an upgraded flow meter to better compare flow from one end of the pipeline to the other, installing three pre-eminent bypass pumps at lift stations in the wastewater collection system and replacing an existing 2006 reserve portable generator at Master Lift Station D.

As part of the FDEP consent order, the town’s approved projects total about $290,822, which surpasses the state’s $281,073 requirement.

While the state rejected Longboat Key’s plan for a wet-well lining project as part of the consent order, the town still decided to reline the interior wet well for Master Lift Station D located at 521 Gulf Bay Road. Bradenton-based GML Coatings completed the wet-well lining, according to Brownman.

Longboat Key is also in the process of advancing a redundant pipeline project, which has an estimated cost of $21.8 million. The town is budgeting for the redundant pipeline project in fiscal year 2024. It will ultimately replace the existing pipeline, which was built in 1973.

Brownman said the reassessment is for the town to identify any “discrete, isolated issues” to address in the short term.

Even though a town-hired consultant found that an estimated 14.7 million gallons spilled from June 17-30, 2020, about 400 feet from the shores of Sarasota Bay, Brownman said Longboat Key did not require an immediate pipeline replacement.

If the assessment finds otherwise, Brownman said the town could consider the possibility of obtaining a long-term loan to move up the redundant pipeline project. 

“We believe we can do (the reassessment) at a lower cost (and) lower budget on a repair standpoint while we continue to pursue the longer-term project simply because of the age…the service life of the pipeline itself,” Brownman said.