New technology uses aluminium & copper to extract phosphorus from water

An innovative project near Nubbin Slough, spearheaded by Curt Cramer of NuQuatic Advanced Water Technologies, is utilising aluminium and copper to extract phosphorus from the water.

About the process

This process employs a galvanic reaction initiated by the electrical connection of aluminium and copper in water. This reaction releases a small amount of aluminium, which then reacts with the phosphorus, forming aluminium phosphate that precipitates out of the water. The resulting solids are subsequently removed and disposed of in a landfill.

The NuQuatic process is covered by 59 U.S. and foreign patents and applications. The project at Nubbin Slough is the world's first and only full-scale galvanic phosphorus removal initiative. Galvanic cells, which operate without an external power source, generate electric current through a spontaneous chemical reaction.

The six tanks housing these galvanic cells can treat up to 8.6 million gallons of water per day. The phosphorus concentration in the canal water ranges from approximately 200 to 400 parts per billion (ppb), and the treated water returned to the canal has a significantly reduced phosphorus level of around 50 ppb.

A new contract

The South Florida Water Management District (SFWMD) has entered into a pay-for-performance contract with NuQuatic for the Lake Okeechobee S-191 Basin Surface Runoff Phosphorus Removal Project. Under this $6 million contract, NuQuatic will receive $312 for each pound of phosphorus removed, with an expected removal of about 10 tons of phosphorus over approximately two and a half years. The facility has been constructed with sufficient aluminium to last for three years.

Curt Cramer noted that while the NuQuatic process cannot treat all the water flowing into Lake Okeechobee, it is effective in targeting "hot spots" with high phosphorus levels. Additionally, this technology could be integrated into wastewater treatment plants to remove phosphorus before the wastewater is discharged. Typically, water discharged from wastewater treatment plants in Florida contains phosphorus levels of around 500 parts per billion (ppb) or higher.

NuQuatic process and its significant benefits

Curt Cramer also mentioned that the NuQuatic process could be adapted to remove nitrogen from the water, converting it into a form that can be released into the air. The project site near Nubbin Slough was chosen due to its high phosphorus levels, among the highest flowing into Lake Okeechobee. According to data from the South Florida Water Management District (SFWMD), this basin contributes approximately 36.4 tons of phosphorus to the lake annually, based on the most recent five-year average.

High phosphorus levels in the water significantly contribute to harmful algae blooms in Lake Okeechobee. Historically, before the flood control system and the channelisation of the Kissimmee River, the phosphorus level in Lake Okeechobee was around 40 parts per billion (ppb). The flood control system enables millions of people to live in Florida and moves water faster than naturally intended. Instead of slowly sheet flowing—which allowed vegetation to clean the water—the water is now rapidly transported down the Kissimmee River into the lake. Although the central third of the river has been restored to its natural winding path, water is still pumped rapidly into Lake Okeechobee in emergencies, such as after Hurricane Ian.