Researchers reinventing household water and sanitation one modular system at a time

Researchers at Rice University’s WaTER Institute are leading an ambitious new effort to transform the way the world manages water and sanitation at the household scale. The project, funded by the Gates Foundation and in collaboration with Arizona State University, Clarkson University and Duke University, aims to develop modular, field-ready water treatment systems capable of recycling multiple household wastewater streams and dramatically reducing both water use and dependence on centralized infrastructure.

The work builds on Rice’s previous Gates Foundation-funded research that developed innovative solutions for treating individual wastewater streams like urinal and laundry water. This next phase expands the scope dramatically.

“Previously, we were focused on each individual stream,” said Qilin Li, the Karl F. Hasselmann Professor of Civil and Environmental Engineering at Rice, who is leading the project. “Now we’re asking: What if we could handle all of the water streams inside a home — urine, laundry water, shower water, kitchen water — and treat them together in a modular system that enables sanitation, water reuse and resource recovery for the entire household?”

The project seeks to integrate a suite of advanced technologies into a single scalable treatment system that can be installed directly at the household level, producing clean nonpotable water for reuse, recovering valuable nutrients and eliminating waste safely without chemicals or biological processing. The system will rely solely on physical separation and catalytic degradation, eliminating the need for complex monitoring or chemical dosing.

The Gates Foundation’s Reinvent the Toilet Challenge estimates that 3.5 billion people worldwide lack access to safe sanitation, a crisis that threatens global health and disproportionately affects rural and low-income communities. The foundation is now accelerating commercialization and deployment of the most promising technologies in its portfolio, and it has identified Rice as a critical integrator capable of turning innovation into real-world systems.

“Gates is looking across their entire portfolio and trying to determine how to accelerate commercialization,” said Eric Willman, executive director of the Rice WaTER Institute. “They see Rice as a strong facilitator because of our long track record — we can integrate different modular processes, adapt them for households and move them to market.”

Although the global sanitation crisis is the primary driver, the system could improve water management in the United States as well. According to the U.S. Environmental Protection Agency, more than 20 million households nationwide rely on septic tanks, which are expensive to maintain and prone to failure and groundwater contamination.

“If you can replace septic tanks with better technology, you not only improve sanitation but also reduce dependence on groundwater and enable water reuse,” Li said. “That’s critical because groundwater is scarce and increasingly contaminated.”

Rainwater harvesting, another component of the project, could allow homes to operate entirely independently of municipal water, which could be a potential game changer for drought-stricken regions like Arizona and parts of Texas.

“It’s not that centralized systems were a bad idea; they’ve saved more lives than almost any other public health innovation,” Willman said. “But duplicating or expanding them is extraordinarily expensive, even here in the U.S. We believe the future is a hybrid approach where distributed systems complement centralized infrastructure to create real resilience.”

Rice is also working with the Gates Foundation to develop a business plan for a Center for Household Water and Sanitation within the WaTER Institute designed to accelerate commercialization and build partnerships with industry.

“This is a huge technical challenge, but it’s also a huge business opportunity,” Willman said. “If we get this right, we can improve billions of lives. And we know we can’t do it alone — we’re actively looking for commercialization partners, manufacturers, investors and entrepreneurs who want to help deploy these technologies at scale.”

The flexibility of a modular design that can adapt to different plumbing configurations, climates and resource needs adds further momentum.

“This research gives us a chance to rethink water for the next century — to build systems that are resilient, affordable, chemical-free and truly circular,” Li said. “That’s the kind of change the world needs.”