Wastewater pipeline to remain after replacement installed

The town of Longboat Key’s wastewater pipeline is more than 51 years old. 

The 20-inch ductile iron pipe was installed in 1973 and put into service in 1975.

In 2020, that pipe failed, leaking somewhere between 11 million and 17 million gallons of sewage. That 22-square-inch rupture was blamed in part on a buried log that had been underneath the pipe since it was constructed.

The leak made it evident to town leaders that a replacement pipe was necessary, a process that has been in the works since. The landward section of the pipe was replaced in 2023 for $2.6 million. Installation of the underwater portion of the pipe is expected to begin later this year.

The old pipe will remain.

“The town looks at it as a very expensive conduit to the mainland,” Longboat Key Utility Manager Jessie Camburn said. “So once our new pipeline is in service and we aren’t using the old main anymore, we want to preserve it so at some point we can reline it. When you reline the inside of a pipe, it makes it like brand new again.”

Relining it is a complicated endeavor, but it’s cheaper than constructing a new pipe. The process, called cured-in-place pipe lining, was described by Camburn as a three-step process. First, a bag is threaded through the empty pipe. Then, the bag is inflated to the interior diameter of the pipe. Third, hot water is run through the system, “cooking” the bag and curing it in place. 

“Right now it’s not doable,” Camburn said. “There’s technology coming out soon that they think they can do a stretch that long because it’s 11,000 feet long. But on smaller lines we do it all the time here on Longboat Key.”

Camburn said if and when the old pipe is relined, it could then be used to transport treated wastewater back to the island to be used as irrigation.

“They treat it to the point that we can now pump it back to our yards and irrigate with,” Camburn said. “Right now, Manatee County is running out of reuse water, which is good. They’re using as much wastewater as they can to turn into reuse. Though some day, they predict 20 years from now, we might be able to get that source as well.”

The only thing that has been decided by the town is leaving the old pipeline in place. With technology not progressed enough, and Manatee County reuse water inventory capped out, the town is merely envisioning a possible reuse of the metal pipe that will continue to lay where it has sat for decades.

“It’s a way future project,” Camburn said. “It’s years and years out. But it’s thinking ahead. It’s thinking of an option and protecting a resource. It’s a very expensive conduit that’s installed under the bay. If we can find out how to refurbish it, it’s very valuable.”