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USF team creates device to recycle human waste into water

TAMPA — Consider the toilet. Most people don't spend a whole lot of time thinking about it.

Even so, that porcelain throne is the deceptively simple starting place of what is, in reality, a remarkably complicated and expensive system that pipes our malodorous waste to some distant spot for its transformation into a harmless byproduct.

Not something developing nations do well, given the cost.

But a researcher and his team at the University of South Florida are this month preparing to ship to India a portable, self-contained sewage-treatment device they hope will eventually help solve the sanitation needs of developing nations.

The device, called NEWgenerator, powered only by solar energy, transforms almost all waste into water for irrigation, methane gas that can be used to generate energy and nutrients found in fertilizer. NEW stands for nutrients, energy and water.

After more than a decade of development by Daniel Yeh, a USF associate professor of civil and environmental engineering, this prototype will be shipped to a community in southern India for testing with the hope that it will eventually be mass produced.

"The need that this will fill is potentially huge," Yeh said. "You and I don't think much about sanitation. In the houses we live in, there's a toilet and we just use it and we don't think about it. But 40 percent of the world's population actually lack that on a daily basis. They have to think about where they will go relieve themselves."

More people on the planet, the United Nations says, have mobile phones than access to flushing toilets, and Yeh said roughly 2.6 billion people could benefit from the technology.

For much of the world's population, "going to the bathroom" is often done outdoors in unhealthy conditions.

"It's done in very dirty, smelly conditions," Yeh said. "It's not only a huge health problem, you can see that there's also a big human dignity problem associated with that. Safe sanitation is hugely critical, but often neglected because it's something that people don't like to talk about."

Yeh started work on the system in 2002 when he was a postdoctoral researcher at Stanford University, before coming to USF in 2005. His project has received $200,000 in funding from the Indian government, $100,000 from the Bill and Melinda Gates Foundation and $50,000 after the USF team won the Cade Museum Prize, a competition for inventors and entrepreneurs.

The heart of the NEWgenerator is what Yeh calls a "bioreactor," a tank in which microorganisms break down waste, producing byproducts such as methane. The unit also uses multiple membranes that filter the wastewater, and then adds chlorine as a safeguard against harmful organisms.

The system can recover what most wastewater systems discard, such as the nitrogen that can be used in agriculture.

In fact, one side of the NEWgenerator holds a series of pipes to hold hydroponic plants fed by a stream of nutrient-rich water. (Water might also be piped to a greenhouse.)

"It provides a nice aesthetic to the system so you don't just have this unsightly white box in the community," said USF doctoral student Jorge Calabria, 26. "It's the physical representation of converting what is commonly seen as useless waste into something beautiful and useful."

If the device works as intended in India, Yeh said, USF may license the technology to a company to mass produce, or he might even create a start-up company to market it.

In India, the device will be connected to "e-toilets," which are self-cleaning bathrooms that can be monitored remotely by computer. The USF team did not develop the e-toilets, which are themselves something new in the waste industry.

While self-contained wastewater systems have been used on cruise ships and in "green" buildings for years, what sets the NEWgenerator apart is both its carbon and physical footprint — both small.

The device, housed in a durable container used by defense contractors in shipping supplies to troops overseas, is just 40 square feet. That is an important consideration for a device that may need to fit in a crowded neighborhood with little available space.

At 4,000 pounds, it can be easily moved by a forklift.

Once set up in India — USF doctoral student Robert Bair will monitor the device and collect data — the NEWgenerator can handle the waste of up to 100 people a day.

The project wouldn't have been possible without the assistance of two unlikely sources — a charter school in Lutz and a little bit of cat food.

Yeh and his team used cat food to help test the technology. Perhaps many cat owners already know that cat food, soaked heavily with water, mimics human waste.

And to test the system in the real world, the USF team processed waste from a septic tank at the Learning Gate Community School, an environmentally focused charter school in Hillsborough County.

Yeh said he viewed human waste as more opportunity than liability.

"It's messy business," he said. "I think we're sort of in this interesting position that we're doing something most people wouldn't want to do."

Contact William R. Levesque at Follow @Times_Levesque.

USF team creates device to recycle human waste into water 10/06/15 [Last modified: Tuesday, October 6, 2015 10:42pm]
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