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USF professor hopes to save resources through waste

A USF professor is working on improving a machine that can create energy from human waste.

Daniel Yeh, associate professor of civil and environmental engineering at USF, has been working on the machine, called NEWgenerator. for years which can recover energy from human excrement.

“NEW stands for nutrients, energy and water,” he said. “We recognize that these are the three things that we can recover from waste material. We look at this as a device that can generate these things.”

Based on Yeh’s research, the machine can potentially recover methane, ammonium and phosphate, all compounds that are used as energy sources. Yeh said it’s been estimated that the world only has about 40 years left of phosphorous reserves on the planet, a non-renewable source that helps grow plants.

This semester, Yeh received a $100,000 Grand Challenges Explorations grant from the Bill and Melinda Gates Foundation, which assists healthy living in developing countries, according to its website.

The NEWgenerator has not been tested using sewage yet. The current grant is part of Phase I of the project, where Yeh has 18 months to demonstrate that the NEWgenerator can be used at the community level in developing countries. If he’s successful, he will compete for $1 million as Phase II of the grant.

“What we’re interested in is to target developing country applications, to make this unit more rugged, more simple, maybe reduce the energy that is needed to run the system,” Yeh said. “Those are the targets from the Gates Foundation grant. You can think of this as space-age technology.”

The machine’s technical term is anaerobic membrane bioreactor because it uses anaerobic microorganisms that break down wastes into carbon and transforms that into methane, which can be used for fuel. The system also uses membrane technology that turns waste into clean water as well as nutrients such as nitrogen and phosphorous, which help to grow plants.

In the lab, Yeh has experimented with cat food, which he said has a chemical composition similar to that of human waste.

“It’s going to be a real crisis situation when we start running out of phosphorous,” Yeh said. “We don’t have a substitute for phosphorous and just about all life forms need it.”

Yeh said the importance of the machine is highlighted by the fact that there are 7 billion people on the planet and scientists have been asking how it’s possible to sustain so many people as resources are being depleted.

“The answers lie within the waste materials that we produce,” he said. “This waste is something that is processed through our bodies, but it was previously food. Our bodies took the nutrients, and what’s left is carbon, nitrogen and phosphorous,” he said.

The Grand Challenges Exploration grant is part of a competition that occurs every six months. Yeh said more than 2,000 applications were submitted worldwide and his was among the 5 percent to gain approval.

Robert Bair, a graduate student studying civil and environmental engineering who is helping Yeh in the grant process, said he agrees that people need to look at the bigger picture when dealing with human waste.

“The historical approach to wastewater has been that it is something nasty, but it’s something we have to treat so we can put it back in the environment,” Bair said.

Yeh said he’s worked on the project since joining USF in 2005, but began the research as a post-doctoral researcher at Stanford University in 2002.

Bair said this technology is important because it works on sustainable ideals.

“It models the natural environment where everything is in cycle. There is no real waste within the natural cycle,” he said. “We’re starting to realize that as long as humans exist, we will produce waste, so we can either treat it as waste or use it to recover water, nutrient and energy.”

Yeh said he thinks the entire world can eventually benefit from the NEWgenerator.

“We want to start by focusing on developing countries,” he said. “But I think even here in developed countries, here in the U.S., we can benefit from something like this.”