Students design water-testing tool, win $40,000 award

A team of UW engineering students won a $40,000 award to develop their method of monitoring water purification using the sun’s rays. The tool, designed by students from the UW’s chemical, electrical and bioengineering departments, uses electrical components to indicate when water purified by the sun is safe to drink.

The idea began with bioengineering doctoral student Jacqueline Linnes, who traveled to Bolivia with the UW chapter of Engineers Without Borders last year. While there, she learned to disinfect her water by leaving it out in the sun, a common method of purification in developing countries.

Ultraviolet rays from the sun kill microbes in the water, rendering it safe to drink. However, most people who use this method lack a reliable way to know when the process is complete.

“There are currently about 45 million people in the world who are using this process for disinfection,” said Charlie Matlack, an electrical-engineering doctoral student at the UW who worked on the project. “They just don’t have a tool to tell them if they’re doing it correctly or not.”

The device is made out of commonly available electrical components. Matlack said it consists of the same things you would find in a cheap solar calculator, just programmed differently.

The resulting product is a device that attaches to water bottles, measures exposure to sunlight, indicates when it is safe to drink and can be built for $3.40. It is designed specifically with portability and low cost in mind in order to make it accessible to users in the developing world.

“All we’re really doing is measuring how much sunlight hits the bottle over time and using that as a proxy to know how far the solar-disinfection process has gone,” Matlack said.

While the process doesn’t remove or filter out contaminants, it does kill the bacteria that cause diarrhea, a serious illness in the developing world.

“The real consequence we’re trying to mitigate is that the leading cause of death for children worldwide under 5 is diarrhea caused by [drinking] unclean water,” Matlack said.

The grant was the top prize in a competition sponsored by the SODIS (solar disinfection) Foundation, a Bolivia-based nonprofit. The foundation now owns the rights to the method and is working on implementing it on a larger scale for disaster relief. Linnes, Matlack and UW public-health graduate student Tyler Davis are currently using their share of the grant money to develop the water-bottle indicator idea into a functioning nonprofit. Though the foundation owns the right, they have been given permission to develop the model, and hope to manufacture the indicator for global use.

“We’re working on getting more funding, and then the next step is refining the electrical design,” Linnes said. “Then we want to get a working prototype and field test it.”

They’re planning on forming into a tax-exempt organization later this month.

The researchers hope that their effort will improve living conditions in areas without readily available clean water.

“Ideally, it will help save a lot of lives,” Linnes said. “A lot of people don’t have the resources to use other purification methods, so hopefully this will work for them.”

Reach reporter Ryan Dunn at news@dailyuw.com.

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