Agriculture is broken. Traditional techniques use too much energy and produce too little food for our growing planet. One fix: skyscrapers filled with robotically tended hydroponic crops and lab-grown meat
Posted 09.04.2008 at 4:06 pm
THE AQUAPONIC MERRY-GROW-ROUND: Graham Murdoch
Although hydroponics and fish farms produce high yields, they’re also high-maintenance. Soilfree hydroponic systems require frequent nutrient replenishment, and fish tanks need constant flushing of fouled water. But pair the two in one “aquaponic” system, and the flaws become virtues: The fish waste becomes plant fertilizer, while the plants clean the dirty water.
This automated “conveyor belt” system, conceptualized by
OrganiTech, an Israeli company that creates automated farming systems, takes aquaponics one step further. The tank’s slow current carries floating trays of plants  past nutrient dispensers  and, by the end of the weeks-long trip, the plants are ready for harvest. Below them swim high-protein tilapia , whose ammonia-laden waste sinks to a gravel bed , where bacteria convert it to nitrogen. The system pumps this nitrogen-rich water to the plants, which consume the nitrogen and return clean water to the fish.
CROP CIRCLES TENDED BY ROBOTS: Graham Murdoch
Farmers already score per-acre yields using hydroponic tactics that are 30 times as high as those produced by traditional farming. In a vertical farm, nutrient-delivery machinery and 24-hour light exposure would improve on that yield many times over.
But not all plants respond well to hydroponic methods. Some, such as potatoes and citrus trees, need to set root in a semisolid medium, like soil or coconut fiber. The design here, by the Canadian company Omega Garden, does just that. In this Ferris-wheel-like growing system, plants grow in porous, vermiculite-stone-filled trays  arranged in a cylindrical cart  that rotates to periodically dip each row of plants in a nutrient trough .
THE WHOLE THING RUNS ON SEWAGE: Graham Murdoch
The vertical farm is more than just a produce factory. It’s also a plan to rewire a city’s infrastructure to mimic natural-resource cycles. Nowhere is that more evident than in the tower’s basement, where sewage provides the farm’s most crucial resources: energy and water. The surrounding city’s sewage system would be redirected to the farm, where half of it would enter a “SlurryCarb” machine, developed by EnerTech, a green-energy start-up in Atlanta. The device heats and pressurizes the sludge , breaking it down into its base components—carbon and water. The machine extracts the water , and the solid, coal-like slurry burns to power steam turbines  that generate electricity. The rest of the sewage is treated with bacteria-killing chemicals and turned into topsoil through a heating and drying process developed by N-Viro, an Ohio-based biosolids-recycling company. Water extracted from both processes is filtered  through natural “bioremediators,” such as zebra mussels, cattails and sawgrass, that clean it until it’s suitable for agriculture, or further refine it for drinking. Any farming waste is composted to make fertilizer and methane gas, which can be burned for energy.