Troubled Waters: ‘What can we do’ to fix lagoon?

Florida Institute of Technology’s Indian River Lagoon Research Institute hosted the fourth annual TechCon in Melbourne Sept. 28, where some 70 scientists, engineers, conservationists and planners from Florida and around the U.S. discussed the latest methods of trying to fix the ailing water body.

“What’s next? What can we do? What’s the next innovation we can apply?” Dr. Robert Weaver, co-organizer of the technical conference with Dr. Kelli Hunsucker, asked the audience. “Let’s not be daunted by the pessimism. Let conferences like this keep us on track and inspire us to find solutions.”

One of the main topics of the day-long session was control and removal of muck – fine-grained sediments, rich with organic material and topped by drift algae – that is the primary source of the nutrients nitrogen and phosphorus fouling the lagoon.

According to Florida Tech’s Dr. Austin Fox, about 76 tons of nitrogen per square kilometer per year comes into the lagoon from muck. “If we do nothing, it will never go away,” Fox said.

The scientist has been working with John Sawyer of Arc Surveying and Mapping on ways to “surgically remove” contaminated sediments from the lagoon. Sawyer said he’s come up with a method of injecting electrical current into the water to locate muck deposits and make a map, backed up by test borings, that can avoid dredging non-contaminated soils.

“I would like to survey the entire Indian River Lagoon and provide current locations and quantities of contaminated sediments,” Sawyer said. “It would tell you where you are today.  You would have a baseline.”

Florida Tech graduate student Leigh Provost said she and colleagues are developing and testing a new suction head for removing muck. And Elroy Timmer, senior scientist with Aquatic Vegetation Control, Inc., said his company tested a bacterial management tool called Bio-Zyme in a stormwater treatment area in South Florida that succeeded in digesting muck and improving water quality.

Timmer said the technology has been used successfully in some 20,000 freshwater lakes around the U.S. and suggested it could work in headwaters of canals that drain into the lagoon.

“It works and it’s cost-effective, period,” he said.

Florida Tech’s Dr. Geoff Swain discussed the use of Biorock to restore oyster reefs in the lagoon.  Oysters are an important water quality enhancement tool because each one can filter more than a gallon of water per hour.  Swain said Biorock, developed in the 1970s, uses an electrical current to grow oyster reefs on steel mesh.  But he said it’s unknown how much it might enhance growth of the mollusks in the lagoon.

Other topics included advanced septic tank technologies and policies for protecting the lagoon. Proceedings from the conference may be published later in the Marine Technology Society Journal.

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