A Beaverton start-up has created a floating “lily pad” that uses solar-activated nanotechnology to break down water contaminants.
Puralytics CEO Mark Owen said the device could treat storm water pollution before it reaches nearby waterways if it were deployed in retention ponds or ditches alongside roads and parking lots.
Puralytics has used the same technology to create small-scale drinking water purification systems for backpackers and people in developing countries. Owen said the lily pad is lined with titanium dioxide that, when activated by sunlight, triggers a chemical reaction that breaks down contaminants into benign elements (see detailed explanation here).
“We don’t need any chemicals. We don’t need any power,” he said. “We can do it just with sunlight and nanotechnology.”
There are still some questions about how to apply the technology to real-world storm water pollution. Puralytics will be working with Oregon State University’s Institute for Water and Watersheds to test the treatment system in artificial ponds for the next six months. The company received at $53,000 grant from Oregon BEST to help turn the lily pad into a marketable product.
“The small-scale results indicate everything will work,” said Owen. “We just need to put some large-scale science behind the potential here.”
Stormwater pollution is a chronic environmental problem in cities, where it’s hard to catch all the polluted runoff and treat it before it makes its way into local waterways. When rain water hits pavement and other surfaces, it picks up petrochemicals, plastics and metals from cars, trucks and the rest of the cityscape.
But the lily pad can treat all of those pollutants so they don’t impact aquatic life once the water reaches rivers and streams, said Owen. And it could even be placed on the waterway itself to reduce existing pollution.
“You could picture something in the river where you’re treating a portion of the water, and it’s diluting the contaminants for the whole river,” Owen said. “But it might be more effective near a storm water drain that enters the Willamette River, where it can have more diluting effect.”
Oregon Department of Transportation has expressed interest in using the technology to treat storm water runoff from bridges. Owen said the lily pads could treat that runoff if the water were retained in a ditch for treatment before it enters a waterway.