With roughly 80 percent of California’s already-scarce water supply going to agriculture, it’s crucial for the state to embrace new technologies that shrink the amount of water required to grow food. Alexandru Predonu has designed an elegant solution that uses solar energy to power a rotating desalination plant and farm that not only produces clean drinking water for the city of Santa Monica, but also food crops – including algae. A finalist of this year’s Land Art Generator Initiative competition, a site-specific biennial design competition that has inspired world-renowned designs like The Pipe and Energy Duck, Ring Garden is capable of churning out 16 million gallons of clean water, 40,000 pounds of aeroponic crops, and 11,000 pounds of spirulina biomass for livestock feed.
A desalination plant, rotating aeroponics farm, and algae bioreactor in one, Ring Garden is designed to “harvest seawater, CO2, and the sun’s energy to create food, biomass, and fresh water,” according to Predonu’s design brief. The plant is powered by photovoltaic panels that produce 440 MWh each year. 100 percent of that energy is used to power the desalination process and rotate the garden.
“Seawater enters the desalination plant through special screens that protect fish and local wildlife,” he said. “Solar panels power a high-pressure pump to pressurize seawater above the osmotic pressure and through a semi permeable membrane.”
Clean water resulting from this process is then divvied up – 60 percent irrigates the rotating plants, 30 percent is sent to the city grid, while the remaining brine water, which would be potentially toxic to marine life, is fed through the bioreactor to cultivate spirulina for biomass.
“The aeroponics system uses 98% less water than conventional farming and yields on average 30% more crops without the need for pesticides or fertilizers,” says Predonu. “Ring Garden demonstrates that the main elements a plant needs in order to grow—water, sun, nutrients, and CO2— are on site and don’t need to be transported. On a footprint of about 1,000 m2 (10,764 square feet) the farm can produce vegetables that would otherwise take 26,000 m2 (279,862 square feet) of land and 340 million gallons of fresh water per year.”
If built, Ring Garden would consume just nine million gallons of water annually, according to Predonu, and redirect 331 million gallons that would otherwise evaporate to 2,300 California households.
Every good LAGI design is expected to have a compelling public art and educational component, and Ring Garden delivers. Not only is the design slightly tilted so that the sun will shine right through the middle of the wheel on Earth Day (April 22), but visitors are welcome to visit the facility by boat, and pick vegetables and plant new ones at an outdoor aeroponics garden. There would also be a Eco Awareness Center designed to inform the public about the benefits and necessity of sustainable innovations that promise a more hopeful future.
The winners of LAGI 2016: Santa Monica will be announced at Greenbuild in October.