Ashok Gadgil: The Humanitarian Inventor

His work on water purification, cookstoves, and arsenic removal has helped tens of millions of people worldwide

5 min read
Ashok Gadgil: The Humanitarian Inventor
Photo: Gabriela Hasbun

No! No! No! In Ashok Gadgil‘s cluttered office at the Lawrence Berkeley National Laboratory, hidden among the stacks of books and awards and whiteboards and ID badges from humanitarian organizations, you’ll spot tiny pictures of former U.S. first lady Nancy Reagan. “Just Say No!,” each picture implores.

Gadgil has appropriated Reagan’s antidrug slogan for his own ends. “I tend to say yes too often,” he says, laughing. “Saying no is valuable, because I’m interested in lots of stuff, but my time is full.”

Gadgil’s career is a testament to being interested in many things. Starting with a Ph.D. in physics in 1979 from the University of California, Berkeley, he moved from working on the general theory of relativity, to applied math, to computational fluid dynamics, to mechanical engineering. “Kind of a convoluted way to get there,” he admits. “But I wanted to do something that was closer to having a societal impact.”

Video: Lemelson-MIT Program

For more than two decades, Gadgil has focused his energy and expertise on devising technologies that can help the poorest and the most vulnerable. Early on, he realized that to provide the biggest benefit to the most people, he’d have to be both disciplined and pragmatic in selecting which projects to undertake.

His first foray into socially beneficial technology was sparked by a 1993 cholera epidemic [pdf] in south and southeast Asia, which left thousands dead. Preventing outbreaks of such waterborne diseases could potentially save millions of lives worldwide each year. So Gadgil began investigating ways to use ultraviolet light to disinfect water, focusing on making the system as reliable and affordable as possible. By 1996 he had devised a 60-watt water treatment unit (later reduced to 40 W) that’s the size of a microwave oven and runs on a car battery or solar cell, sterilizing 15 liters of water per minute with minimal oversight or maintenance. The lab patented the system, called UV Waterworks, and then licensed it to WaterHealth International, a company that specializes in providing drinking water to rural communities. To date, about 5 million people have benefited from Gadgil’s system, which has saved 1,000 or more lives per year.

“It’s good,” Gadgil says. “It needs to go to 500 million.”

Ashok Gadgil

IEEE member

Age: 65


Environmental engineer, Lawrence Berkeley National Laboratory and UC Berkeley


Berkeley, Calif.

Hero Moment:

He’s devoted his career to identifying technologies to benefit the most vulnerable—and then inventing them.

The water purifier was just a start. In 2004, the U.S. Agency for International Development (USAID) asked Gadgil to help design a more efficient stove for the millions of refugees living in camps in the western Sudan region of Darfur. Traditional wood-burning stone fireplaces are inefficient, and women must risk their safety to hunt for firewood or else trade their food rations for fuel.

“I didn’t want to design a stove for Darfur,” Gadgil admits. “People had been designing fuel-efficient stoves for 30 years. So I said, ‘Here are some stoves. Why don’t you get some and test them?’ “ Instead, his USAID contact asked Gadgil to test the stoves himself. It soon became apparent that none of them was enough of an improvement, so Gadgil led the development of an entirely new design: the Berkeley-Darfur stove.

Now on its 14th iteration, the Berkeley-Darfur stove burns less than half the wood or charcoal of a traditional stone fireplace, boils water almost twice as fast, reduces CO2 emissions by over 1.5 metric tons per year, and saves the average family in Darfur the equivalent of US $300 per year in fuel. Getting from version 1 to version 14 involved focusing on what the refugees needed and wanted. The stoves were modified to make them cheaper and simpler to manufacture locally; refugees receive them for free, while local villagers can buy the stoves for $20. About 40,000 of them are now in use in Africa.

Although the stove’s design hasn’t changed much since 2009, Gadgil continues to learn how users modify them to suit their needs. As it turns out, a tiny fraction of users can afford to buy charcoal, which burns well in a Berkeley-Darfur stove only if the stove is inverted—a design possibility Gadgil and his team never considered. “People are creative everywhere,” he notes. “You always find surprises like these, but they’re good surprises.”

Located in the hills above the UC Berkeley campus, Lawrence Berkeley National Laboratory commands a gorgeous view of San Francisco and the Golden Gate Bridge. The land here would likely be packed with multimillion-dollar homes if it weren’t instead devoted to “bringing science solutions to the world,” as the lab’s slogan puts it. Gadgil’s stove lab is housed in a small shed that used to store radioactive materials. It sits behind a thick concrete wall intended to protect nearby buildings from stray radiation.

When we stop by, three grad students are measuring smoke-particle distribution with lasers. The stove is now being adapted for use in countries with different cooking techniques, including Ethiopia, Haiti, India, and Mongolia. More generally, Gadgil and his team are trying to find ways to reduce particulates, carbon monoxide, and other toxic emissions by a factor of 10. These emissions cause more than 4 million premature deaths annually, mostly among women and children. Cutting the emissions involves figuring out, among other things, where smoke is generated inside a flame and how to maximize the combustion of fuel. One idea is to increase the turbulence inside the flame with a thermoelectrically powered fan, but doing so would add cost and complexity to the stoves.

After we leave the stove lab, we drive down Cyclotron Road onto the Berkeley campus to see Gadgil’s water lab. Inside is a prototype of his next project: a low-cost, sustainable way to remove arsenic from drinking water. Over 60 million people in India and Bangladesh drink groundwater that’s been naturally contaminated with arsenic at up to 100 times what the World Health Organization considers safe. And arsenic poisoning now kills one out of every five adults in Bangladesh.

Gadgil notes that many people have tried to do arsenic decontamination at the household level. “But in most of the developing world, the infrastructure doesn’t exist,” he explains. “People normally leave their home to collect water.” Insights like these helped Gadgil think about the scale of the technology that was needed. He concluded that centralized water sources are the easiest to integrate into communities and the most efficient to build and maintain.

Gadgil and his students have been exploring several methods to perform the actual arsenic removal, generally involving binding up the poison into a precipitate that can be filtered. But the removal technology is almost secondary to the economic and cultural issues of making clean water as accessible and affordable as possible.

“Knowledge of how people live, and what their practical lives are like, has been useful in forming the design and vision of dissemination or implementation,” Gadgil says. “And that gets folded into the design itself.”

On the way back up the hill to Gadgil’s office, I ask him how it feels to have been recently inducted into the National Inventors Hall of Fame for his work on safer drinking water. Gadgil’s hexagonal tile at the hall, in Alexandria, Va., hangs between those of Steve Jobs and Arthur Fry, inventor of the Post-It Note. Indeed, most of the Hall of Famers “do phenomenal work, but it’s been predominantly with first-world markets,” Gadgil observes. His work, which the citation says has made a difference in the lives of about 100 million people, “is kind of a departure,” he says.

Gadgil feels he’s only midway through the development of the stoves and arsenic-removal systems. The next steps will be to move the innovations from his labs into the world at a scale where they can have a real impact.

And after that, even more problems are waiting, he says. “There is always this scanning the horizon for where I could make a difference. What are the serious problems where I could apply my knowledge and my skills? There are many of them. We’re not short of problems—we’re short of bandwidth.”

Gadgil laughs, and from behind his computer monitor, a tiny Nancy Reagan offers him advice.

About the Author

Evan Ackerman ( @BotJunkie) is a contributing editor for IEEE Spectrum.

An abridged version of this article appeared in print as “The Humanitarian Inventor.”


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