New solutions for an age-old problem

On a rainy Sunday afternoon in late November, Daniel Yeh and two graduate students disassembled their invention, careful to wrap pieces of plumbing in cardboard. Their toilet - along with the shipping container where it's housed - traveled to Kerala, India that month. That's where Yeh and his team have unveiled a stand-alone sanitation system, the NEWgenerator, which stands for nutrients, energy, and water.

The environmental engineer and his team methodically plodded along for a decade to develop an energy-independent sanitation system that has the potential to alter the lives of millions of people.

Why did it take so long to reinvent the toilet? "It's funding," said Yeh (pictured above), a professor of civil and environmental engineering at the University of South Florida whose work is supported by the Bill and Melinda Gates Foundation. "Sanitation is really this unglamorous thing that people don't want to talk about. But by not talking about it, this time bomb is created."

And it is a time bomb, in many ways. About 13 percent of the world population, or 946 million people, still defecate in the open. What they leave behind contributes to the transmission of cholera, typhoid, hepatitis A, and polio. Diarrhoeal diseases alone cause an estimated 280,000 deaths annually, according to the #link:http://www.who.int/topics/diarrhoea/en/:World Health Organization.#

But despite the backing of international organizations and the obvious need for better sanitation, researchers still face hurdles trying to convince hesitant officials in developing countries to spend limited resources on newer technologies. Older sanitation methods are the standard, says Yeh. They are cheaper in the short term, but less effective and more costly in the long run.

Dead zones

But poor sanitation isn't just a local problem that affects poor people in developing countries - it has a major impact on the environment as well. The combination of contaminated wastewater from poor sanitation and agricultural runoff can destroy entire ecosystems.

Case in point are coastal dead zones, which are created when these pollutants find their way into rivers and oceans in large quantities. The nitrogen and phosphorous contained in them promotes the growth of phytoplankton and algae, which consume the oxygen at the surface of the water. This so-called hypoxia suffocates seagrass beds, coral and other aquatic animals dependent on oxygen, leaving behind dead zones.

Even worse, these dead zones don't stay in one place, as Johannes Karstensen, an oceanographer with the #link:http://www.geomar.de/en/:GEOMAR Helmholtz Centre for Ocean Research# in Kiel, Germany explains. Instead, they spread throughout the ocean, killing new ecosystems as they go. And this depletion of oxygen is only exacerbated by climate change, he says, as a warmer climate makes it more difficult for oxygen to enter the ocean.

A Greenpeace report noted, such harmful algal blooms indicating oxygen deprived waters had been identified near Kerala at the Southwestern tip of India, as well as a marine dead zone in the West Indian shelf, the part of the Indian Ocean along the country's west coast.

Sarah Moffitt Myhre, an ocean and climate scientist who studies abrupt climate warming, agrees: "We're warming polar oceans and we're changing ocean circulation. And that is directly related to the expansion of oxygen minimum zones."

The number of dead zones has doubled worldwide since 1990, now occupying an area the size of New Zealand. Once established, these zones cannot be minimized. Only future ones can be prevented, Myhre said.

A better toilet

Daniel Yeh is hoping his innovative toilet with help solve these problems - and offer additional benefits in the process. His NEWgenerator is far more than a toilet bowl with a pipe. It contains a bioreactor that houses human waste-eating microbes. As they consume the excrement, the tiny critters produce a biogas that is converted into methane and can later be harnessed to create energy.

What they don't eat is then filtered through a membrane the size of a drinking straw. The membrane traps larger particles that might contain bacteria or viruses but allows water to percolate. It also captures nitrogen and phosphorous ions which are then channeled to provide nutrients for the hydroponic system - flowers or vegetables - affixed to the outside of the toilet-container. Small solar panels on the roof power the system.

"This is what nature would do," Yeh said of the cycle he's established inside the container. He is not entirely a vanguard. Membranes are used in many city-wide sanitation systems in industrialized countries. What's novel is that Yeh has made that technology available off-grid for parts of the world where large-scale sanitation is unavailable.

The NEWgenerator also works in tandem with rudimentary sanitation networks. The bioreactor can be situated next to a latrine, absorbing fecal material from the area for the microbes to eat, reducing the amount of human waste that ends up in waterways.

India leads the world in the number of people who defecate in the open, and just because a new technology is available doesn't mean habits will change. The environmental benefit the NEWgenerator offers is a boon, says Yeh, especially because the system also recycles the water used.

Putting it to the test

"Waste treatment and water recycling treatment is only half the equation," said Yeh. "The first half is that the toilets need to be available and clean."

Kerala-based Eram Scientific is partnering with Yeh to link the NEWgenerator with their eToilet system that automates cleaning. The company has 1,000 #link:http://www.eramscientific.com/:eToilets# across India that cost one or two rupees for individual use. Eram will also work to train mechanics in how to repair the NEWgenerator, using spare parts that should be readily available in India, Yeh said.

But before any of that happens, the technology must first go through a trial run, likely at a Kerala secondary school. One of Yeh's graduate students will spend a year in India overseeing the operation of the system and how it will fare in day-to-day use.