Late last month, the U.S. Department of Energy announced a $100 million research grant to the National Alliance for Water Innovation (NAWI) to lead an Energy-Water Desalination Hub. Meagan Mauter, associate professor of civil and environmental engineering, is NAWI’s research director.

Meagan Mauter, associate professor of civil and environmental engineering. (Image credit: Courtesy of Meagan Mauter)

The five-year project will research and develop cost-competitive and energy-efficient technologies to desalinate nontraditional water sources for diverse end uses from agriculture to municipal drinking water. “Desalination” in this project is much broader than removing salt from seawater. It includes removing contaminants – many of which are salt compounds – from industrial wastewater and sewage, among other sources.

Led by Lawrence Berkeley National Laboratory’s Peter Fiske, NAWI includes four DOE national labs, 19 universities and 10 industry partners. Here, Mauter explains how this very large and potentially transformative project will work, and Stanford’s role in the work.

What does NAWI hope to achieve in the coming years?

We believe that a circular water economy is essential to securing the U.S. water supply. Our 10-year goal is to develop the technologies that enable 90 percent of nontraditional water sources to be reused at the same cost and energy intensity as traditional water sources. Our team has identified six critical technology barriers to distributed water desalination and reuse that will motivate the research agenda for the hub.

That’s a lot to unpack. Let’s start with a “circular water economy.” What does that mean?

Our water systems today are for the most part linear: Extract freshwater, treat to a uniform standard, use, treat wastewater and dispose. This approach has been highly successful in the context of the 20th century when population centers were smaller, industrial water demands were better aligned with water availability and freshwater aquifers were more abundant. Today’s reality is different. As we see in California, we have large population growth in arid regions, less natural water storage in snowpack and depleted aquifers.

While economies of scale and sunk infrastructure costs mean that large municipal systems are here to stay in most areas, many nontraditional water sources are underutilized in this conventional paradigm. To tap those sources – from brackish groundwater to brines (water highly concentrated with salt compounds) from power plants, oil production, saline aquifers used to sequester carbon dioxide, paper mills and beverage and food processing – we need technologies that will allow us to transform a linear water economy into a circular one in which we minimize freshwater withdrawals by reusing wastewater.

And why is it important that your solutions be dispersed and modular?

One of the key features of a distributed water infrastructure system is that every source of water will be slightly different. So, instead of designing a huge, custom-built, central water-treatment plant, we hope to deliver a water treatment unit that functions as a kitchen appliance. Okay, a large kitchen appliance. Seriously, though, we envision mass-produced, prefabricated water-treatment systems that can be paired to provide flexible water treatment solutions. This will allow us to keep treatment and re-use of the water as local as possible.

How can you transform industrial wastewater into a water source that is competitive with more traditional sources?

Much of the cost and energy intensity of industrial wastewater management is actually embedded in the transportation of wastewater via pipeline or truck. This is especially true of distributed industrial water use, for instance in oil and gas development or agricultural wastewater treatment, where users pay both to source freshwater and dispose of wastewater.

Our strategy is to cut water transportation substantially by developing technologies that enable cost-effective distributed treatment and reuse. Even if the treatment costs are slightly higher per gallon, these costs will be more than offset by the lowered transportation costs and the simultaneous provision of clean water.

Will all the research be performed by current NAWI partners?

We will have open requests for proposals that solicit early-stage research that is aligned with the NAWI mission. DOE specifically requested that we focus R&D efforts on technology readiness level 2-4 research, which is essentially focused on moving basic research into the early piloting phase.

This is an exciting stage of technology development to be focusing our efforts on because it will leverage the diverse skills of academia, national laboratories and industry. I’m particularly excited about leveraging the fantastic modeling, synthesis and characterization facilities at the national labs for this important mission. This includes the SLAC National Accelerator Laboratory here at Stanford, though it isn’t one of the founding national labs.

The more diverse the people and assets that contribute to this effort, the more likely NAWI is to achieve its ambitious goals.

Stanford has several faculty members doing related work in water reuse. Do you see Stanford researchers playing a significant role in NAWI?

Stanford will definitely be a key partner. I’m very excited to be directing this research from a university so committed to sustainability and the environment, and from a state highly motivated to address the water crisis. I just arrived at Stanford at the beginning of September, so I’m still getting the lay of the land when it comes to the diverse scientific community that I hope will participate in this hub.

That said, I have many fantastic colleagues in civil and environmental engineering who have been researching water reuse solutions for some time. For instance, the ReNUWIt energy research center is very focused on urban infrastructure systems that facilitate water reuse. Also, the Codiga center has been a tremendous platform for studying the science and engineering challenges associated with municipal water reuse. But that is really just scratching the surface of water-related research at Stanford.

Plus, I really want Stanford alumni working in the water industry – whether at large companies or start-ups – to join NAWI, a process they can start on our website.