Innovative technology removes phosphorus from water

Posted 6/10/24

An innovative project near Nubbin Slough is using aluminum and copper to remove phosphorus from the water.

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Innovative technology removes phosphorus from water


OKEECHOBEE — An innovative project near Nubbin Slough is using aluminum and copper to remove phosphorus from the water.

Curt Cramer, of NuQuatic Advanced Water Technologies, said the process uses a galvanic reaction created by two dissimilar metals – aluminum and copper -- being electrically connected in water. This reaction releases a small amount of aluminum that reacts with and precipitates phosphorus from the water as aluminum phosphate. The solids are removed and disposed of in a landfill.

“A galvanic cell is a battery,” said Cramer. “You use one every day to start your car. We’re using it to clean water.”

The NuQuatic process is the subject of 59 U.S. and foreign patents and applications. The Nubbin Slough project is the first and only full scale galvanic phosphorus removal project in the world.

Galvanic cells use no power. The electric current is generated from a spontaneous chemical reaction.

The six tanks that contain the galvanic cells can treat 8.6 million gallons of water per day. The phosphorus level in the canal water varies from around 200 parts per billion (ppb) to 400 ppb. Clean water returned to the canal is around 50 ppb phosphorus.

The South Florida Water Management District (SFWMD) has a pay-for-performance contract with NuQuatic for the Lake Okeechobee S-191 Basin Surface Runoff Phosphorus Removal Project.  NuQuatic will receive $312 per pound of phosphorus removed. The $6 million contract is expected to remove about 10 tons of phosphorus in about two and a half years. The plant was built with enough aluminum to last three years.

Cramer said while the NuQuatic process can’t treat all the water going into Lake Okeechobee, it can be used in target “hot spots” where phosphorus levels are high. The technology could also be incorporated into wastewater treatment plants, to remove phosphorus before wastewater is released. He said water discharged from wastewater treatment plants in Florida typically has phosphorus levels around 500 ppb or higher.

He said it could also be adapted to remove nitrogen from the water, using a process that would release nitrogen from the water into the air.

Cramer said they picked the location near Nubbin Slough because that water has some of the highest phosphorus levels going into the lake. According to SFWMD data, the water in that basin contributes about 36.4 tons of phosphorus into Lake O per year (based on the most recent 5-year average).

High phosphorus levels in the water are a factor that contributes to harmful algae blooms on Lake Okeechobee. Before the flood control system was built and the Kissimmee River channelized, the phosphorous level in Lake O was around 40 ppb.  The flood control system that makes it possible for millions of humans to live in Florida moves water much faster than nature intended.  Instead of sheetflowing slowly -- which allowed vegetation to clean the water -- water is moved rapidly down the Kissimmee River into the lake. The center third of the river has been restored to it's natural winding path, but in an emergency -- such as after Hurricane Ian -- water is still pumped rapidly into Lake O.

Nubbin Slough, phosphorus, algal blooms, algae, NuQuatic Advanced Water Technologies