Can a better toilet save lives? Duke researchers hope so. - North Carolina Health News
By Greg Barnes
Never in his wildest dreams did Duke University researcher Brian Hawkins think that he would grow up to help design a toilet that could someday save the lives of millions of people.
But here he is now, on the front lines of “Reinvent the Toilet,” a project involving researchers from across the country and more than $200 million in grant funding through the Bill & Melinda Gates Foundation.
Hawkins, a research scientist in the Duke Center for Water, Sanitation, Hygiene and Infectious Disease, has been working on the project for about five years. Other researchers have been at it nearly twice as long.
One might not think it would take so much time or money — British inventor Thomas Crapper perfected the modern-day toilet in fairly short order by adding a floating ballcock and improving the “S” trap.
But for Hawkins and dozens of others involved in the Gates Foundation project, this is no ordinary toilet, with no ordinary set of constraints.
The foundation’s parameters require removing pathogens from human waste and converting the waste to energy, clean water and nutrients. All of that has to be done without access to external electricity or water sources. And, oh yeah, the cost can’t exceed 5 cents per user per day — or $10 for 200 users.
The objective is to create small-scale sanitation systems to serve the needs of an estimated 4.2 billion people worldwide who lack safe sanitation methods now.
No laughing matter
During his five years working on the project, Hawkins has heard his share of crappy jokes, but this is no laughing matter.
According to the World Health Organization, 525,000 children under the age of 5 die from diarrheal diseases every year, many because of unsafe sanitation practices. Diarrheal diseases are the second-leading cause of death in that age group.
The underdeveloped world is counting on Hawkins and the other scientists, who include Jeffrey Glass and Brian Stoner, faculty members in Duke’s Department of Electrical and Computer Engineering. Stoner heads up the project for Duke.
The Duke researchers have built a prototype toilet in a renovated cigarette factory in downtown Durham. They have also taken their show on the road, to the outskirts of Durban, South Africa, and Coimbatore, India. Their findings were reported this month in Science of the Total Environment.
The prototypes in India and South Africa are virtually the same. Rubber bands are spaced apart on rollers, separating liquid from solid waste. The solids are then pushed through a large activated carbon filter. Electricity is run through the liquid to break down the molecular bonds within the remaining salts to produce chlorine-containing oxidants, a powerful disinfectant that kills pathogens. The liquid can then be reused as flush water.
So just to recap, this is definitely not your ordinary toilet.
In India, Hawkins said, researchers placed their prototype at a women’s dormitory in a cotton mill.
In South Africa, the prototype was connected to a women’s toilet in a “public communal ablution block” – a fancy term for bathrooms built into a shipping container that are used by people squatting on land in slums near Durban.
Hawkins said a lack of housing and money forced the people from the city. They now live in shacks and have rudimentary means of electricity and sanitation. Some still defecate in the open. Such slums can be found throughout the developing world.
A major cultural difference also exists between the two countries where the prototypes were installed in 2018. In India, people wash themselves with water and their hands after using the bathroom; in South Africa, they clean themselves with paper, newspaper or other semi-solid objects.
The use of toilet paper has proven to be a hurdle for the researchers. It tends to get stuck in the machinery.
“It really was the gum in the works,” said Hawkins, who acknowledged that the researchers are still trying to work through the problem.
Hawkins said the researchers face other obstacles, as well, most notably the high levels of nitrogen and phosphorus that remain after the treatment process.
According to a news release from Duke, the prototypes met all of the biological parameters and three out of the five international chemical standards for liquid effluent. Now they have to find a way to get the phosphorus and nitrogen levels to meet those standards.
“These two chemicals are of particular concern when you’re discharging water into lakes and streams because too much of either can cause algal blooms,” Hawkins said in the release.
Nitrogen and phosphorus are the primary components of fertilizers, and their presence in waterways can supercharge algae, bacteria and other microorganism growth, depleting oxygen along the way. That can result in fish kills and reduced water quality.
“There are efficient ways of removing phosphorus and nitrogen at low costs for large volumes, or for small volumes at high costs, but not for low volumes at low cost. That’s an ongoing topic of R&D for us,” he said.
But the purpose of the latest study was not so much to determine the prototype’s shortfalls as it was to determine how long critical components of the liquid treatment process can last.
In that regard, Hawkins said, the system performed better than expected.
Where to from here?
Hawkins and the other researchers are now testing the next iteration of their toilet at the same dormitory in India.
While the components are essentially the same as before, Hawkins said, the new prototype is more compact and efficient — “a lot more lean and mean.”
While the researchers focus on building a better toilet, Hawkins has been trying to market the waste treatment system to companies. He estimates that he has talked to 100 companies over the past year.
“The challenge now is finding the right financing to move forward,” Hawkins said. “It does feel like we are at the beginning of an industry that doesn’t quite exist yet.”
Hawkins said researchers talk among themselves about the potential for these toilets, not just in developing countries but here in the United States.
Hawkins believes the systems could help solve the problem of hog waste, which in North Carolina is now stored in lagoons and then disposed of by spraying it on farm fields. Environmental groups condemn the practice, saying it contaminates the state’s rivers and streams and makes life miserable for neighbors of the hog farms. North Carolina is the second-leading hog producer in the country, behind only Iowa.
Production on the horizon
Hawkins believes the world will begin to see production of the new toilets in about two or three years.
And then he laughs.
“We have been saying about two years for about two years now,” he said.
“The big, big thing is getting the cost down.”
If that can be done, and the remaining kinks are worked out of the system, Hawkins said he sees no reason why full-scale production can’t begin soon.
An estimated 4.2 billion people in this world may be counting on it.