Five companies will showcase innovative technologies to remove phosphorus from Lake Okeechobee, thanks to grants from the Florida Department of Environmental Protection.

At the June 5 meeting of the County Coalition for the Responsible Management of Lake Okeechobee, the St. Lucie and Caloosahatchee Estuaries and the Lake Worth Lagoon, Ed Smith, of FDEP, said they initially approved six grants, but AECOM has dropped out. AECOM’s proposal was to work at the Pahokee Marina, separating algae, other solids and toxins from the lake water, cleaning the water and returning it to the lake without nutrients and toxins.

The remaining five projects are:

• AguaCulture will focus on mechanical harvesting of nuisance vegetation and vacuuming up the liquid layer of unconsolidated muck near the bottom of the lake. They will blend the liquefied plant material with the watery muck and pump it through a floating hose system over the dike. Using auxiliary pumps to keep the flow going, the material can be transported to pastures as far as 20 miles away, where it will be spread on an upland area, improving the soil there.  The liquid spray is equivalent to about one-eighth inch of rainfall. Smith said AguaCulture’s original plan was to work in the northwest portion of the lake, but the dry weather left the site they originally planned to use unsuitable. The South Florida Water Management District (SFWMD) found a new location, he said. “They will be in working in some of the canals,” he explained. “They will pump it 6 miles onto an upland site. We thank the Seminole Tribe for helping them find this location. They are waiting on two permits that are waiting on that land use agreement.” He said the project will probably start in July.
• ESD Waste2Water will remove water from a canal near Lake Okeechobee, clean the water using an iron-based phosphorus extraction process and a nitrogen extraction process (releasing the nitrogen into the air), and then send the clean water into the  lake. Smith said they will treat about 1,000 gallons of water per minute. The project will probably start in July or August.
• Eutrophix will start about 2 miles from Canal Point, working in a 1,000-acre treatment area. They will use a chemical application of a modified clay that will trap the phosphorus into a stable mineral. Smith said there is a tentative start date of June 17, at 10 a.m. at Canal Point boat ramp. Smith said the application will only take a few weeks, but then they have 3 years of monitoring to make sure everything stays on site and verify how much phosphorus is contained.
• Sea & Shoreline will use a vacuum dredge system focusing on thick, deep sediment areas on northeast part of the lake. Smith said they will remove muck on south side of the S-308 structure (Port Mayaca Lock). They will take dredged material to a shore-based treatment facility and separate the solids from the water. The water will be cleaned and returned to the lake. The dried muck will be used as a soil amendment. Smith said the dredging project will last about 18 months.
• SOLitude Lake Management will use an alum-based system with a buffered flocculant. They are going to use a barge to treat the area west of the S-308 (Port Mayaca) water control structure. The alum will sequester the phosphorus, which will remain in the lake but be unavailable to plants and algae.

“We will be looking at each of these from a cost-effectiveness means,” Smith said.