Atmospheric Water Generation
The air around us may be the greatest source of available drinking water. Virtually all air has moisture in it, even in the middle of a desert at noon. Extracting that moisture from the air – through a process called atmospheric water generation (AWG) – may provide a possible solution to safe drinking water needs.
First developed for the military to produce reliable drinking water in dry battlefield settings, AWG is now also seen as a good medium- to long-term drinking water source for communities following natural disasters like hurricanes and infrastructure failures as in Flint, Michigan. Installation of AWG systems is often less expensive than delivery and distribution of bottled water.
The AWG system draws air into the device. A layer of air filters removes dust and dirt. The cleaned air is directed to a cooling chamber where the air is chilled to the Dew Point, the temperature at which condensation begins. As with dew in the morning or water that appears on the outside of a chilled glass on a hot summer day, the AWG cooling process produces water inside of the device. That water is then moved within the AWG generator to another chamber where the just-created water is further cleaned via both chemical and biological processes. When necessary, minerals can be added in at this point, as well. Now that drinkable water has been produced, the water is kept circulating to keep microorganisms from growing in stagnant water.
In recent tests by the Environmental Protection Agency (EPA) of the Water-Gen AWG system, there was zero E. coli, a common biological contaminant. Likewise, levels of arsenic, lead, copper and several other metals were either at undetectable levels or at zero.
There were two potential health risks from AWG that were highlighted by the EPA. First, if the air being used has contaminants, those contaminants would be pulled into the AWG generator. If not removed in the filtration process, the water produced could have those contaminants in the drinking water. Second, depending on how it is stored and how long it sits before use, there could be microbial growth in the stored water. Both of those challenges can be addressed with current technology.
Industrial-size AWG units can produce up to 2,500 gallons a day of drinking water. With the average person needing no more than five gallons a day for drinking water and food preparation, one large AWG unit can provide drinking water for up to 500 people. In ordinary civilian settings outside of disasters,
existing freshwater supplies can be used for sanitation, washing, agriculture, and firefighting.
AWG systems are energy intensive, but greater efficiencies are being developed. Depending on the temperature and the level of humidity, the systems produce more (or less) drinkable water. Existing AWG systems are agnostic as to energy source. Power to run the AWG units can come from solar, wind, gas-powered generators, or a traditional power grid. The cost of AWG-generated water is about eight cents a gallon, or 40 cents per person per day.