Hospital hit by Hurricane Milton gets system to grab water from air

A children’s hospital that lost access to water in the wake of Hurricane Milton is now using a device that can collect drinking water directly from the air, in a test of how such atmospheric water harvesting systems could be used to respond to disasters.

“When a hospital has both water and power you’re good,” says David Stuckenberg at Genesis Systems, the Florida-based company that designed the apparatus. The system uses absorbent materials called metal organic frameworks to concentrate moisture from air pumped through the machine, then releases pure water when the material is heated by around 8°C.

Such atmospheric water harvesting systems have long attracted interest because of their ability to operate independently of other water infrastructure. A small but growing number are installed to supply daily water to off-grid communities, and they have been used in cities with poor water infrastructure or arid places where water supplies are unreliable, as well as for military operations. An Arizona-based company called Source that makes solar-powered “hydropanels” has even started selling its air water in cans.

Another way these flexible systems have been used is to respond to disasters that leave communities without a reliable clean water supply. As Hurricane Milton approached Florida’s west coast, Jason Weida, the secretary of the Florida Agency for Health Care Administration, saw an opportunity to try this out.

With Hurricane Ian in 2022, Weida saw how water issues and power outages required some hospitals to close for weeks, with evacuation sometimes required days after the storm itself had passed. He learned about Genesis Systems’ technology while touring damage from Hurricane Helene, which made landfall on 26 September. “I thought, “Wouldn’t this be great for next year’s hurricane season?” he says. “Little did I know that two weeks later we would be preparing for Hurricane Milton.”

Ahead of Milton’s landfall on 9 October, the system was brought to a staging ground for the state’s disaster response. Soon after the hurricane passed, a truck brought it to Johns Hopkins All Children’s Hospital in St. Petersburg where leaking water mains had interrupted the hospital’s water supply. Weida says this particular hospital was a priority because of how challenging it would be to evacuate newborns from the hospital’s large neonatal intensive care unit.

On 10 October, workers hooked up the shipping-container sized system to a generator, and it is now producing up to 2000 gallons of drinking water per day while the hospital’s regular water supply is being fully restored. Stuckenberg says the system can operate more or less anywhere humidity is above 10 per cent, although it becomes less efficient as humidity declines. He estimates that the system installed in Florida’s humid air uses about 0.8 kilowatt hours of electricity per gallon of water.

Jonathan Boreyko at Virginia Tech questions whether the system really can harvest so much water while using so little energy. He says it may still be useful in an emergency scenario, but without more information about how it works, he is sceptical about its claimed efficiency.

Stuckenberg points to a study that he and his colleagues published in 2022, which presented similar efficiency figures. He says the system’s energy requirements are so low because of the way the material they use bonds to water vapour with almost no energy, with most energy used to run fans, pumps and to re-concentrate the absorbent. The 2022 study suggested the system has a theoretical maximum efficiency of just 0.07 kilowatt hours per gallon of water.

In a more general sense, atmospheric water harvesting systems can be an “important tool” for disaster response when water supplies might be offline for an extended period of time, says Paul Westerhoff at Arizona State University, and are well-suited for places with relatively high humidity like Florida. However, he says their reliance on electricity, often from a generator, has been an issue during past disasters.