Pinellas County Waste to Energy Plant Adds Two Buoyant Flow Control Devices
Thirsty Duck installed the two flow control devices July 12 in St. Petersburg, Fla.
The two largest Thirsty Duck TD Series Buoyant Flow Devices (BFDs) in the world were successfully installed on July 12 at the Pinellas County Waste to Energy plant, a solid waste incinerator located in St. Petersburg, Fla.
The BFDs will deliver captured storm water to a reverse osmosis water treatment system being constructed to allow water, drawn from just under the surface of an 18 acre detention pond, to be recycled for use in the facility’s cooling system. The project is being undertaken in an effort to reduce the discharge of pollutants to Tampa Bay, Fla. Tampa Bay has been designated as an “Outstanding Florida Waterway” by the Florida Department of Environmental Protection, and a number of TMDLs have been established for the bay in recent years.
The Thirsty Duck installation features two, 30-in. floating “Duck” bodies which discharge through 14” inside diameter bellows at a combined flow rate of approximately 2,100 gpm (3 MGD). The Ducks are equipped with screens on their undersides to prevent alligators, fish and turtles—which inhabit the pond—from being drawn into the treatment system. They also feature a larger diameter top plate to discourage turtles from climbing out of the water and resting on top of them.
Water levels in the pond can vary as much as 11 ft, and the BFD’s are equipped with a cable guide system to prevent the Duck bodies from bumping into each other when wind and waves are acting on the large open surface area of the pond. The guide system features a 20-ft high galvanized steel tower, which supports a beam from which two sets of tensioned ¼-in. diameter stainless steel cables are suspended. The cables pass through the Duck bodies and are anchored to specially fabricated bellows to pipe connecting flanges located below the water surface.
Due to the depth of water in the pond, the contractor elected to assemble the Thirsty Duck installation on the pond bank. The water treatment system project was designed by the Tampa, Fla. office of AECOM and is being constructed by Ortega Industrial Contractors Inc. of Jacksonville, Fla.