From The Editor | October 24, 2014

Sun-Activated LilyPads Remove Contaminants Without Chemicals

Laura Martin

By Laura Martin
@LauraOnWater

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Puralytics LilyPads are hardly noticeable in the ponds, lakes, and catchment areas where they are deployed. Made of mesh and plastic, the flat, 1-meter diameter disks could even be confused for their plant namesake if not for their white color.

But while Puralytics LilyPads may not stand out in their environment, the technology behind them is certainly getting noticed.

Puralytics’ light-activated photochemical contaminant-removal technology — utilized in the LilyPads — has been recognized with the USTech H2.O Exemplary US Water Technology award, the International Water Association Global Honour Award for Drinking Water Supply, the BlueTech Innovation Tracker award, and many other honors. 

The technology can safely remove pesticides, herbicides, heavy metals, petrochemicals, pharmaceuticals, and micro-organisms from water bodies without any chemicals or waste discharge and with minimal installation and maintenance requirements.  Each LilyPad can treat 1 cubic meter per day of contaminated water without impacting the health of the fish and plant life that reside there.  

“You simply drop it in, and it floats right below the surface of the water and begins cleaning it,” explains Mark Owen, the founder and CEO of Puralytics. “The nanotechnology mesh material responds to sunlight, and oxidation reduction reactions occur at the surface of the mesh. This breaks apart almost any chemical, takes out heavy metals, and destroys all contaminants that come in contact with it.”

The technology is ideal for sites struggling with stormwater runoff.

“If you had a building or a site and you were trying to address your stormwater, LilyPads could be part of the overall solution,” says Owen. “Stormwater is one of those things where there are a lot of problems that are starting to be recognized and acknowledged, but the solutions are just catching up.”

In addition to the regular round LilyPads ideal for use within a lake or stream, Puralytics also offers rectangle-shaped LilyPads that can be placed in the troughs often used to transport runoff from roads and bridges to nearby rivers. These treat the water as it is being collected and prevent environmental contamination.    

Industrial sites, such as textile or pharmaceutical plant, can also benefit from deploying LilyPads. They can be placed in retention pounds, catchment areas, or nearby bodies of water that receive runoff from the plant.

“They offer the benefits of advanced treated without all the complications of trying to implement a treatment system,” says Owen. “They are best for water runoff that is partially treated but has residual organic chemicals or other problems that could be addressed.”

The LilyPads can also be utilized for agricultural and mining runoff water treatment, rainwater purification, and open-cover water storage tank applications.

How They Work

The Lilypad technology uses a five-step photochemical process that destroys contaminants rather than capturing them and creating a hazardous waste disposal problem. First, the sunlight activates a nanotechnology-coated mesh to generate hydroxyl radicals, which break apart chemical contaminants. This process is called photocatalytic oxidation. Next, photocatalytic reduction occurs, which reduces toxins such as mercury, silver, arsenic, and chromium to more readily adsorbed materials. Those toxins further break down during the photolysis step that follows, along with atrazine, amoxicillin, DEET, and all estrogenic chemicals.  During the fourth step, photoadsorption, heavy metals are absorbed, including mercury, lead, selenium, arsenic, permanganate, and other compounds. Finally, photo-disinfection occurs, which utilizes ultraviolet disinfection (UV) to remove pathogens more effectively than standard UV lamps.

Looking Ahead

LilyPad technology is still in its early stages. Several pilot projects are in the works, but Puralytics is still looking for those interested in implementing the technology to do more testing on different applications.  

“We are trying to gather as much data as we can,” says Owen. “We feel there is a lot of potential for this technology.”

The biggest benefit of the LilyPad technology is that it addresses a problem that often gets overlooked.

“Once a lake, stream, or pond gets polluted from stormwater, or industrial or chemical runoff, what do you do?”  Owen asks. “Most focus on trying to prevent runoff or treat the water before it goes into the lake, and that is great. But a solution is needed to help recover the body of water once it is polluted. That is where LilyPads come in.”