A product that sequesters phosphorus in the sediment and keeps it from mixing into the water column is one of five innovative technology projects on Lake Okeechobee funded by grants from the Florida Department of Environmental Protection.

“Lake Okeechobee is really important to South Florida and to Florida overall,” said Dr. Mark Heilman, Vice President of Environmental Restoration & Advocacy for SePRO, the parent company of EutroPHIX. He said the big lake is an inland sea that has been polluted with an overload of nutrients from a disturbed watershed. The phosphorus levels in the lake water are several times higher than the healthy level for the lake, he explained. The excess phosphorus can feed harmful algal blooms, he said.

Over the years, muck containing high levels of phosphorus has built up on the lake bottom. When the muck is stirred up, the phosphorus is released into the water column.

Heilman said the EutroSORB product will inactivate phosphorus in the sediment. The demonstration project will sequester about 17,000 pounds of phosphorus, he said.

Scott Shuler, EutroPHIX Director of Technology and Operations, said the natural, mineral-based phosphorus-absorbing product, EutroSORB, will sink into the sediment.

The product is made of benign materials. “This is not an organic chemistry derived in a lab,” he said. “This is not a pesticide or an algaecide. It doesn’t kill algae.”

He said lanthanum is used in human medication to control problems with excess phosphorus. “People have been taking that medication for decades with no detrimental side effects.”

He said the product does not cause a change in the water’s pH. “The materials are very stable and only bind phosphorus,” he said.  “The number one element lanthanum wants to bind with is phosphorus,” he said. If all the phosphorus is tied up, the material will bind with arsenic, he added.

Once the phosphorus is bound, if the sediment is disturbed, the EutroSORB might move around, but the phosphorus will not be released, he explained.

The project area covers 1,000 acres, about 2 miles from Canal Point in the “Mud Zone,” near the center of the lake. Phosphorus levels in that area are higher than in sediment elsewhere in the lake. The modified clay material will trap the phosphorus into a stable mineral.

On the spray boat, the EutroSORB  powder is mixed with lake water, which is pumped into the tank at 150 gallons per minute and sprayed into the lake, on a grid pattern tracked by GPS. The molecules that bind with the phosphorus are microscopic. They settle to the lake bottom where the molecules bind with and sequester phosphorus.

The application will only take a few weeks. It will be followed by 3 years of monitoring to verify how much phosphorus is contained.

Soil samples will be taken at 28 sites inside the target area and 8 sites outside the target area every six months. Water samples will be taken at 3 sites inside the target area every three months.

The product has been used to treat excess phosphorus in ponds and lakes all over the country, said Shuler. “We recently did a demonstration project on Lake Deeson in Polk County.”  He said the phosphorus levels in that lake were 60 to 90 parts per billion (ppb). (Phosphorus levels vary in different parts of a lake.) After the phosphorus in the sediment was sequestered with EutraSORB, the phosphorus in the water has been maintained at 25 to 30 ppb.