When city soil is too polluted to grow fresh vegetables, there may be another way to practice urban farming: Build a hydroponic greenhouse on a billboard.
In Lima, Peru, an experimental billboard sucks humidity out of the air to water plants through system of drip-irrigated pipes, making it possible to grow thousands of heads of lettuce in a week.
The billboard was the brainchild of UTEC, Lima’s University of Engineering and Technology. Two years ago, the university built another billboard that could harvest clean drinking water from Lima’s air–a new solution for the city’s water shortages that doubled as a clever ad to attract new engineering students. This year, the school decided to adapt the same technology to grow food.
“With the “Air Orchard,” we want to demonstrate that engineering is part of our lives around us, and show the creative side of the career,” says Jessica Rúas, marketing director for the university. “It shows that engineering manages to find real solutions to real problems.”
In Peru, farms struggle with polluted soil and water that leaches heavy metals like lead and arsenic into vegetables. By moving to a hydroponic system, it’s possible to grow healthier produce. Growing by a busy roadside leads to other risks–like air pollution from passing cars–but the team behind the technology says that it’s able to filter out the smog.
“The technology has a number of filters that purify the water and keep it clean,” says Ignacio Montero, director of business innovation at UTEC. “So, depending on the need, the water generated is ready for human consumption or agricultural use.”
Though the billboard is an ad for the school, the same technology could be adapted for commercial food production. The key, say the engineers, is to build it in a location that has enough humidity in the air–Lima happens to have muggy air that the system can use to water plants, but in other cities, the technology might not work.
As an ad, it helped the university draw in new students. “We’re showing young people that the rationale of UTEC is to train highly skilled engineers that provide solutions to the challenges of humanity without neglecting the impact in the environment,” says Rúas.