Flying back from the IEEE Visualization Conference, I was walking through O’Hare Airport and found this hydroponics setup. They were growing mostly herbs, which they claimed were used by the O’Hare restaurants, and some tomatoes. They used small plugs (shown in the foreground), in which the seeds were germinated, then placed the plugs in the towers (in the background). The towers used a pump to get the water to the top of the towers, and drip onto the roots growing inside the pipes.
Pretty neat setup.