by Amber

Aeroponic Farm & Desalination Plant Combo

Romanian architect Alexandru Predenu aims to supply fresh water and locally grown food to Santa Monica with an exciting new aeroponic farm and seawater desalination plant combination. Yes, there’s an abundance of fresh food available in California, the warm climate is perfect for year around crops. However, most of it is grown using water-hungry conventional farming methods. Obviously, in a drought-stricken state with a naturally dry climate, major changes are needed. Especially when agriculture is responsible for 80% of the water usage. The Ring Garden offers some interesting solutions.

A finalist of the 2016 Land Art Generator Initiative competition, Predenu’s design marries sustainable food production with a renewable source of drinking water for the City of Santa Monica. But it’s bigger than that. The aeroponic farm produces food for humans, farm animals, and it’s own energy… simultaneously. All of the structure’s functions run on solar power through photovoltaic panel collection, and energy created in algae bioreactors. It also harvests CO2.

According to the diagram accompanying Predeu’s submission, the rotating aeroponic farm allows the crops on each of the 34 spokes to remain in an upright position using gravity. This provides even sun exposure to all crops no matter where they are on the ring at any given time.

No dimensions are provided to give us an idea of the Ring Garden’s actual size. However, annual production capabilities are stated as:

  • 440 MWh of power
  • 16 million gallons (60 million liters) of fresh water
    • 10.6 million gallons (40 million liters) for crop production
    • 5.3 million gallons (20 million liters) for city water supply
  • 40,000 pounds (18,000 Kg) of locally grown food
  • 11,000 (5,000 Kg) of livestock feed

At a glance, it may seem that the crops are still hogging fresh water, but it’s actually conserving 331 million gallons of water needed to grow the same yield using conventional methods. The aeroponic farm, as anyone with some knowledge of high tech growing knows, produces a more abundant harvest per square foot than traditional soil growing allows. It also uses 98% less water than outdoor growing, where that much of the irrigation required is lost to evaporation.

The harvested seawater enters the facility through special screens for protecting fish and wildlife. The solar panels provide energy to run the high-pressure pump that forces seawater above the osmotic pressure, and through a semi-permeable membrane.

Predenu Ring Garden Diagram

Clean water created through this process is sent to the aeroponic farm and the city water supply in the appropriate proportions. The brine that remains after the desalination isn’t safe to return to the ocean, where it could cause a toxicity to underwater life. It’s not really toxic waste, and will be put to good use growing spirulina for feeding livestock.

Since the Ring Garden uses seawater, the plant nutrients are naturally present in the filtered water. And being indoor agriculture housed in a closed system, the crops will be pesticide-free. Predenu’s aeroponic farm design has a footprint of roughly 1/4 acre (1000 m2), but will produce the same amount of food that requires 6.5 acres (26,000 m2) of farmland. The desalination plant will also create enough fresh water to supply 2300 homes a year.

We won’t know until Greenbuild Expo in early October if the Ring Garden is the winner of the competition, but it is the only entry that includes food production. They are all beautiful, and function to generate energy or water, yet nothing compares to the sustainability offered by Predenu’s entry.

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The garden played a starring role from spring through fall in the house Amber was raised in. She has decades of experience growing plants from seeds and cuttings in the plot and pots.