A solar-powered way to clean stormwater
by Stephanie Basalyga
An Oregon product designed to provide clean drinking water in Third World countries may also hold the solution to a problem that plagues construction sites: how to clean stormwater. Beaverton-based Puralytics first caught widespread attention when it unveiled the SolarBag. The bag, which uses sunlight to clean contaminated water, has been used in 60 countries around the world, according to Mark Owen, Puralytics’ CEO.
Owen’s company is now working on an overgrown version of the SolarBag. The new product, called the LilyPad, is in the spotlight for its potential to not only clean large sources of water in impoverished countries and disaster areas, but also serve commercially viable markets such as construction and agriculture. Owen, a self-described “serial entrepreneur,” started Puralytics seven and a half years ago with an eye toward using LED light to activate nanotechnology to purify water. That early search resulted in a product called the Shield, an LED-powered purification system designed for decentralized drinking water systems, multiunit housing or small-scale water stations. Even as they developed Puralytics’ first product, Owen and his staff began to ponder whether they could replace LEDs with sunlight to purify contaminated water. Their search resulted in the creation of the SolarBag.
The SolarBag quickly caught the attention of the tech community and captured a string of awards for Puralytics, including a grand prize for best clean technology business at the 2010 CleanTech Open. But Puralytics wasn’t done noodling ideas for better – and bigger – ways to clean contaminated water. With a 3.5-liter capacity, the SolarBag was limited to producing a maximum of 10.5 liters of clean water per day – enough for a single person. Owen and his staff wondered if they could make a larger version of the bag to clean a much larger volume of contaminated water.
“The question was: How big could we make it, and could we treat the water source?” Owen said.
At the time, Owen figured the product that would become the LilyPad would again find its main purpose in areas where pure drinking water is a problem. Owen envisioned it being used mainly in open-topped water tanks and ponds. But as he talked to people about the product, he soon realized it also might have commercial potential.
“There’s been tremendous interest from the (construction) industry,” Owen said. “We’re looking at its potential to clean stormwater, to clean water used on farms for crops.”
Creating a product for widespread use in a commercial market would be a big boost for Puralytics. The high costs associated with developing technology – the SolarBag and LilyPad both rely on a combination of five processes – require tech startups like Puralytics to rely on investors and funding from sources like Oregon BEST.
Money from Oregon BEST, which works to direct research revenue from multiple sources to companies in the state, helped Puralytics work with Oregon State University to conduct an initial phase of research on the LilyPad.
“The LilyPads are designed to float on the water surface,” said Tyler Radniecki, an assistant professor of environmental engineering at OSU. “We did some lab tests with (collected) stormwater and found that four inches of standing water is the ideal depth.”
Armed with that information and $94,000 more from Oregon BEST, Radniecki is ready to start a second phase of LilyPad testing for Puralytics. The testing will be done in a rain garden area at the OSU-Benton County Green Stormwater Research Facility in Corvallis, which will allow Radniecki and one of his students to study how the LilyPad stormwater treatment technology performs in real-life conditions.
“(The facility) has all the bells and whistles as far as monitoring,” Radniecki said. “We can measure water flow, sunlight. For Mark’s technology that I’ll be testing, that will be critical – how the sunlight intensity affects the rate of contaminant absorption. “(The LilyPad) is designed for more than one-time use, so we’ll (also) be looking at how long they last, how leaf debris that falls on top of it affects it.”
For Radniecki, the LilyPad testing results will provide material for papers for peer review in scientific journals and a topic for his assistant’s master’s thesis.The tests also promise to provide civil engineers with information about ways to make it easier to maintain rain gardens, according to Radniecki. Rain gardens often are used to help clean stormwater, but they require a high degree of care.
“Maintenance is a big thing with rain gardens,” Radniecki said. “A rain garden needs the grass mowed. You have to clean the silt. You have to take care of the plants, but a lot of times that doesn’t happen.”
During the testing phase, Radniecki and his assistant will examine whether the presence of the LilyPad changes the amount of maintenance that needs to be done to keep the garden in proper working order. As for Puralytics, if the testing upholds expectations, the company will be able to walk away with what it says is crucial for earning recognition – and commercial acceptance – for the LilyPad.
“One of the challenges is that you need third-party certification and a qualified lab to talk about results,” Owen said. “The industry really wants to see that. “This is going to help us cross that gap for internal testing to formal field training with a well-monitored application in a public setting. It will give us the (real world) data. That’s essential.”