John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
The high-tech billboard transforms atmospheric moisture into drinking water for thirsty Peruvians.
Lima is the second-largest city in the world to be situated in a desert, right behind sand-blasted Cairo. That means the Peruvian capital's 7.6 million residents have a great and persistent thirst for clean water, which certainly isn't being fed by the 1.1 inches of rain Lima received during an average year.
The coastal city does have one great source of water, though. It's in the air. Peruvians have their faces dampened each day by an extraordinary amount of humidity, which reaches 98 percent saturation on some days. Now, an unlikely alliance of scientists and advertisers have figured out a way to take that damp air and in effect squeeze it like a sponge, producing tasty torrents of fresh agua for Peruvians to slurp.
It's a billboard, albeit an ingeniously modified one. Researchers at the Universidad de Ingeniería & Tecnología and ad agency Mayo Publicidad have built into the towering structure a large reverse-osmosis system, complete with air filters, a vapor condenser, a carbon filter and a cold tank. Moist air gusts waft through those devices, in that order, and wind up as cool water sloshing in a 5-gallon tank.
People with buckets line up at the base of the billboard and fill 'er up via a spigot. The billboard has produced 2,496 gallons of liquid in the past 3 months – about 25 gallons a day – and is valued over water from wells, according to a local man in the above video, because that stuff is "not nice and it's polluted."
What a refreshing dislocation from the general direction that marketers are taking high-tech urban advertising, such as those bus shelters that emit potato smells or stalk you via weird text messages. Here's the Lima billboard in action:
Photos courtesy of UTEC.