Literally wringing a new water supply out of thin air, San Diego International Airport is demonstrating that drought-induced ingenuity can tap an unlikely place.
The water comes from air conditioners on passenger bridges at eight gates at the airport’s Terminal 1. The air conditioners reduce burning fuel the planes would otherwise use while on the ground. That reduces pollution.
As a byproduct, the air conditioners produce condensate that runs onto the ground, spreading in puddles that mostly evaporate away. That water can also erode concrete and also poses a potential safety hazard.
Last year, employees brainstormed what to do with this water. The answer was to collect it in barrels and use it to wash down the airfield, sidewalks and vehicles.
From August to December 2014, air conditioners at six gates produced more than 5,200 gallons of condensate, according to the San Diego County Airport Authority, which runs Lindbergh Field. This month, air conditioners at two more gates were added to the collection program for a total of eight.
More than 420,000 and 840,000 gallons of condensate are expected to be collected and reused this year, the authority says. That equals the amount of water used by three to five single-family households in a year. Passenger bridges at other terminals are newer designs with built-in lines that carry condensate directly into the sewer system.
Total annual water use at the airport is about 78 million gallons, mostly for bathrooms, sinks, water fountains, concessions and cleaning.
“Like most organizations, residents and businesses in the region, we’re looking at our whole portfolio of water use and ways to save,” said Brendan Reed, environmental sustainability manager at the airport. “For our Terminal 2 expansion, we put in much more water-efficient landscaping. We’ve also done some recent irrigation and landscaping projects at the beginning of Terminal 1.”
This non-potable water will replace fresh water once used for that purpose, said Amiel Porta, the authority’s manager of terminal operations. More water is being collected than is needed for cleaning purposes, he said. It may be possible to use the additional water for landscaping, if it passes water quality tests.
The setup is simple: a hose collects water condensate from the passenger bridge, and sends it down to a 55-gallon barrel, Reed said. A contractor, Ocean Blue, places the water in a 500-gallon storage tank atop a trailer, and takes it to a power washer.
“We have two power washers, one of which has a 350-gallon capacity and the other has a 150-gallon capacity,” Porta said. “We power-wash five days a week, Tuesday through Saturday.”
The power washers are mainly used in areas where people transit, on curb fronts and arrival and departure roadways.
Depending on the terrain, the water is either vacuumed up for reuse, or soaked up in large fiber logs called “straw wattle” so it doesn’t get into the storm drains.
Another source of non-potable water is available, Porta said, potable water stored for emergency use. The water can’t be stored indefinitely; health regulations say the water “expires” within a year, and must be replaced.