Nanoscientist lectures on diminishing supply and high demand for fresh water
Seth Darling discusses the supply and demand for fresh water around the world and how scientists are trying to develop new ways to clean and filter water. Photo by: Lloyd DeGran
The Golden Age of Water—characterized by clean, abundant and cheap water—is ending, according to Seth Darling, a nanoscientist at Argonne National Laboratory and a fellow at the University of Chicago’s Institute for Molecular Engineering. “This is going to reshape how we live, raise food, organize communities and function in our entire economy,” he said at “The End of Water as We Know It,” an Argonne OutLoud at UChicago lecture on May 18.
Although water crises are still rare in America, they are part of daily life around the world. Eighty percent of the world’s sewage is discharged into waterways without treatment. Agricultural runoff is creating enormous algae blooms. In many developing countries, girls have to walk miles to fetch water, something that prevents them from attending school. Every 90 seconds, a child dies from a water-related disease. And on the geopolitical scene, water is an issue in border disputes and used as a weapon of war.
The problem is a lack of fresh water, which makes up less than 3 percent of the earth’s water. Of that fresh water, the vast majority is tied up in icecaps, glaciers and permafrost. Much of what is available to humans is being diminished by climate change, droughts, unsustainable utilization and other factors.
While supply is diminishing, “demand for fresh water is skyrocketing due, in part, to population growth and development,” Darling said. “Global demand is projected to rise 55 percent in the next 35 years.”
A big part of the problem is that water’s role in the production of everyday consumer goods is overlooked, he added. There are 37 gallons of water embedded in a cup of coffee, 634 in a hamburger and 39,000 in a car. “We’re moving a lot of virtual water around the world and not policing it in an efficient, organized way,” Darling said.
For these reasons, Argonne and UChicago are looking for solutions to the water crises. They are focusing on advanced material technologies, informing policy with analysis, agroscience and pollution mitigation.
One of the most promising areas of water research at Argonne and the University is membrane technologies. Membranes are used to filter and desalinate water. “We’re developing all kinds of advanced technologies for membranes to clean themselves and effectively remove pathogens, metals, salt and other impurities from water,” Darling said.
Commercially available ultrafiltration membranes typically have holes of various sizes, which lets some pathogens through. “We’re using a technique called self-assembly, in which polymers organize themselves into tunable structures that are the right shape and scale.”
Additional research includes Atom Trap Trace Analysis, which analyzes trace isotopes as a way to date groundwater.
“Like politics—all water is local,” Darling said, so Argonne and the University have teamed up with the Metropolitan Water Reclamation District of Greater Chicago and other organizations on Current, a public-private partnership that unites the region’s researchers, entrepreneurs and utilities to solve water problems. It will conduct research, disseminate new water technologies and encourage the reuse of waste water.
“The Romans did something that we are just getting back to,” Darling said. “They had different streams of water for different purposes.”
This could move Americans away from the practice of flushing 6 billion gallons of clean drinking water down the toilet every day, he added. “All water can be cleaned and reused,” he said.
Water should be cleaned to a certain level depending on its projected use, Darling said. The notion of “clean water” sounds desirable, but pure H2O is poisonous to humans because it would leach nutrients from the body. Such ultra clean water is needed for semiconductor manufacturing, but not to water the lawn.
There are many ways to clean water, including filtration, distillation, disinfection (with chorine and/or ultraviolet light) and the methods most municipal authorities use: a combination of coagulation, flocculation, sedimentation and filtration.
Ultimately, better pricing—with protection for basic access for all—will help people realize the value of water, which Darling described as the most important material in the world. “We’re not paying as much for water [in America] as we should,” he said, “especially considering that we spend as much buying bottled water as we do maintaining our entire water infrastructure.”
“Start seeing water,” he admonished the rapt audience. “Don’t wait for the well to run dry.”
Argonne OutLoud at UChicago is a free public lecture series that highlights cutting-edge research taking place at Argonne, UChicago and other collaborative research institutions. It is supported by the University’s Office of the Vice President for Research and for National Laboratories, and this lecture was held at and in partnership with the University’s International House.