University of Calgary

Waste not

Submitted by tdroden on Thu, 09/15/2011 - 17:00.

Waste not

Schulich researchers Ian Gates and Michael Kallos look for a poop-to-power solution to a global health problem
By Jennifer Sowa

Schulich engineers Ian Gates, left, and Michael Kallos have received a research grant from the Bill and Melinda Gates Foundation to explore ways to develop sustainable energy from human waste. (Photo by Riley Brandt)Schulich engineers Ian Gates, left, and Michael Kallos have received a research grant from the Bill and Melinda Gates Foundation to explore ways to develop sustainable energy from human waste. (Photo by Riley Brandt)

Every now and then you gain a new piece of knowledge that makes you realize perhaps you’ve been a bit wasteful when it comes to a potentially valuable resource. Basically you’ve just been flushing it down the toilet.

At the Schulich School of Engineering, chemical engineers Ian Gates, BSc’89, and Michael Kallos, BSc’95, PhD’99, are exploring the possibilities of developing a sustainable energy source with one particular substance and addressing a global health problem at the same time.

The thing with this project, though, is that it’s apt to cause a lot of people to turn up their noses. Not because the science stinks, but because what they’re working with does.

Gutters carrying sewage run along the streets in northern Ghana. (Photo by Elizabeth Logan)Gutters carrying sewage run along the streets in northern Ghana. (Photo by Elizabeth Logan)“Everyone poops and pees, and some do it several times a day. So there’s plenty of raw material out there,” explains Gates.

Yup, you read that right. Poop and pee. Feces and urine. Human excrement. Whatever you want to call it, we’d probably all agree that people generally want to get rid of it. But these guys want more of it.

We usually picture chemical engineers experimenting with, well, chemicals. And technically, Gates and Kallos are. After all, fecal matter is mainly a combination of water, fat, fibre and protein. Break those down into their basic compounds—carbon, hydrogen, oxygen and sulphur—and you start to look at feces in a new way. Poop can be a problem solver. The challenge is squeezing as much of that potential out as possible.

Picture a high-tech toilet. A high-tech toilet with all the bells and whistles which, in this case, doesn’t mean one of those comfy cushioned seats. A clever invention to be sure, but what Gates and Kallos are thinking of is much more impressive. Try a built-in chemical reaction chamber that transforms urine and feces into solids for fertilizer and gas that can be burned to produce heat and electricity. They’re aiming to make that a reality for the people in the world who need it most.

“The goal is to create something useful for communities in developing countries,” explains Kallos. “Our idea combines anaerobic microdigesters and thermoelectric heat and power generation. The individual components already exist. Anaerobic digesters, for instance, have been processing agricultural animal manure for a long time. It’s a matter of integrating the components in a new way.”

The vision involves more than an endless supply of energy. This could also help attack a major human health problem: disease and death caused by a lack of proper sanitation facilities. While millions take elaborate sewer systems for granted, the norm in many countries involves pit latrines, ditches, even farmers’ fields right next to the crops. According to the United Nations, more than a billion people worldwide practice open defecation.

Elizabeth Logan, BSc’04, can vouch for what it’s like for a North American to find herself in a remote region of Africa with a bathroom consisting of an open pit and a grove of trees. Logan is a chemical engineer actively involved with Calgary’s professional chapter of Engineers Without Borders. She worked in Ghana with the Ministry of Food and Agriculture two years ago, and one particular memory is as vivid as ever: a young girl playing alongside a road, scooping up a vile concoction of raw sewage in her little kid’s cup and scampering off.

“I don’t know what she was planning to do with that water and who-knows-what-else,” recalls Logan. “And it’s not just human waste. Garbage often gets dumped in as well.”

A group of trees serves as a family’s washroom in Ghana. The family’s crops are in the front. (Photo by Elizabeth Logan)A group of trees serves as a family’s washroom in Ghana. The family’s crops are in the front. (Photo by Elizabeth Logan)Rampant raw sewage is a health crisis of such magnitude that it prompted the United Nations to declare 2005-2015 the Water for Life Decade. The top priorities are increasing access to clean water and proper sanitation systems.

The UN estimates that 2.6 billion people—that’s more than 40 per cent of the planet’s population—have no access to hygienic facilities that prevent humans from coming into contact with feces. Diseases caused by water contamination and fecal-oral contact kill nearly two million children every year.

Transforming human waste into useful products and energy would be an effective method of disposal.

The idea caught the attention of the Bill and Melinda Gates Foundation and it awarded Gates (no relation) and Kallos a US$100,000 research grant last April. Their proposal was one of 88 selected from a pool of 2,500 applications from around the world for funding under the Grand Challenges Explorations program. The focus is on finding solutions to global health problems and helping what the foundation calls “bold” and “unorthodox” projects get off the ground.

Other projects that received grants include an “eMosquito Net” mobile phone application that would release high-frequency sound waves to cause vibrations and disrupt the navigation capabilities of disease-spreading mosquitoes, a hand-held ultrasonic device for measuring the water content in the soft tissues of newborn babies to prevent deaths from dehydration, and a “smart diaphragm” for pregnant women that would monitor changes in the vagina and cervix and wirelessly alert health-care providers before preterm labour begins.

“Despite the progress in global health and development, we vitally need creative ideas to discover and deliver life-saving vaccines, eradicate the next disease or slow the spread of preventable diseases,” says Dr. Tachi Yamada, president of Global Health at the Bill and Melinda Gates Foundation. “One bold idea is all it takes to catalyze new approaches.”

While the poop-to-power concept certainly sounds bold, it’s already well-established in the field of environmental engineering. There are projects all over the world that involve energy production from biogas that comes from the feces of people and animals. Biogas contains methane, a fuel.

Biogas facilities are common in developing countries such as India and China. They process organic kitchen waste, plant residuals and animal or human waste from small communities or individual households. Household-sized biogas units are usually constructed with locally available materials such as bricks or pre-cast concrete rings. Each can produce enough gas to meet the cooking and lighting needs of a small family.

A simple latrine in Africa. (Photo by Nadia Berger)A simple latrine in Africa. (Photo by Nadia Berger)Public toilet complexes are also catching on in some regions of the world. In India, the Sulabh International Social Service Organisation has built 7,500 public toilets and 200 plants to process the biogas.

Large anaerobic reactors fed with either sludge from municipal wastewater treatment plants or animal feces, such as the waste from feedlots, are common in developed countries including Canada. The City of Calgary operates three biogas facilities and just one of them can produce as much as 42 million kilowatt hours of electricity in a year, enough to power almost 6,000 households.

These projects have one important factor in common: they’re big. And lots of poop has lots of potential to generate electricity.

Gates and Kallos are proposing a scaled-down version that takes this concept all the way to the household level. Add to the mix the extra complexity of electrical generation—requiring another stage in an already complicated chain of steps—and you can understand why poop-to-electricity has never been done at this scale. The big question is whether it would be practical and economical.

And as with any new technology in a developing country, just the simple fact that the thing works isn’t enough.

“You need to have someone in the community who has the knowledge to fix it,” explains Logan. “I’ve seen problems even when the technology isn’t very complex. You can go into rural areas of Africa and see simple generators or boreholes that no longer work because they don’t have the supplies or the skills to maintain them.”

In other words, it’s the ultimate engineering challenge: designing a simple solution for a complex problem.

“We need units that are virtually foolproof with very few moving parts,” Gates agrees. “A major focus for us is on researching sustainable materials that are locally available and investigating ways to build the units at a low cost.”

Early work on the project began with the concept that is evolving into more detailed designs. Gates and Kallos plan to have a prototype built by the end of the year.

Next step: putting it to the test. They need to pick a location in a developing country because experimental results will be influenced by environmental conditions such as temperature and humidity. Gates and Kallos expect to make a few trips back and forth in the next few months.

If their project shows promise, they could be eligible to receive another grant from the Bill and Melinda Gates Foundation worth up to US$1 million.

“This health crisis is causing an astounding number of people to suffer around the world,” says Kallos. “If we can help just one per cent of them, the impact could be huge.”

And so, Gates and Kallos are knee-deep in a project that’s just as exciting in its vision as it is daunting in its complexity.