Flushing a toilet isn’t a notable part of the day for most individuals. Yet for 2.6 billion people, it isn’t even an option. In developing countries, the lack of access to safe sanitation contributes to a range of issues, from disease and chronic health conditions to violence and disrupted education, which disproportionately affect women and girls.
Diana Yousef ’03 (’04SIPA), who has three young daughters, felt driven to tackle the world’s sanitation issues, such as the lack of toilets and waste-disposal systems in much of the developing world. She addresses them with her company, change:WATER Labs, which aims to find solutions that provide access to safe water and sanitation for vulnerable people. The company’s first product—the iThrone, a stand-alone waste-evaporating toilet—requires no electricity or plumbing infrastructure.
Yousef’s expertise in science, international affairs, and business positions her to pursue this goal. In addition to her MBA, Yousef has a PhD in biochemistry from Cornell and a master’s from Columbia’s School of International and Public Affairs. She has worked in consulting and venture capital and co-founded multiple social impact ventures.
“The problem I kept gravitating toward was water,” says Yousef. “My family comes from the Middle East, and I’ve seen how important water is there. Water touches every aspect of people’s lives: their health, their ability to sustain themselves economically, their food security, their political security.” No toilet in a home means women and girls must venture out at night to public communal toilets. “This can render them susceptible to harassment or assault,” explains Yousef. No toilets in schools means children must be uncomfortable and distracted while they try to learn, putting them at an academic disadvantage.
"Ultimately, we hope to find ways that sanitation can pay for itself and create value and opportunity in communities." — Diana Yousef
Yousef originally planned to develop a system to separate water from contaminants to produce clean drinking water, but her idea morphed when she tested materials and realized there was value in simply extracting water from solid waste. “I started thinking that if we could do on-site volume reduction of waste, we could do a better job of containing it so it doesn’t pollute communities, making people sick and poisoning their water,” she says. “And by shrinking it, we can drastically reduce the cost and frequency of collecting and removing it.”
Change:WATER Labs’ iThrones require no water, power, or plumbing; instead, they use a membrane, developed by Yousef, made from a moisturewicking polymer that evaporates 90 to 95 percent of the sewage. The toilet is a box-like structure containing pouches made of the evaporative membrane; liquid and solid waste are collected in the membrane, and the water is removed from the waste. Yousef refers to this as an “evaporative flush.” The liquid then leaves the toilet in the form of clean water vapor through a distillation process that uses the breathable membrane in place of heat and boiling. What remains is a much smaller amount of waste to dispose of, which takes cost out of the sanitation system.
The company is launching a pilot program in Uganda—funded by a Humanitarian Grand Challenge grant—and has partnered with a local hospital and school that will make the toilets available.
Yousef is already researching her next related product, a “pee-powered battery,” or bio battery, which, she explains, “will use waste that goes into the toilet to power active ventilation in the system and enhance evaporation as well as control odors.”
Yousef’s vision for the future is to create selfsustaining sanitation infrastructures that could use waste as the raw material for other needs, such as energy or fertilizer. The waste being produced in the world is a constant, so harnessing it for productive processes could prove to be powerful. “Ultimately,” she says, “we hope to find ways that sanitation can pay for itself and create value and opportunity in communities.”