The CAS integrates tilapia aquaculture with vegetable hydroponics. The system intensifies production on a small area of land, reduces the amount of water needed to produce 2 separate crops and reduces wastewater discharge into the environment.
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System components
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US customary units | SI units |
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Four fish rearing tanks (ea.)
|
2,060 gallons | 7,800 liter |
| Two cylindro-conical clarifiers (ea.) | 1,000 gallons | 3,785 liter |
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Four filter tanks (ea.)
|
185 gallons | 700 liter |
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One degassing tank
|
185 gallons | 700 liter |
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Six hydroponic tanks (ea.)
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3,000 gallons | 11,356 liter |
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Total plant growing area
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2,300 ft2 | 214 m2 |
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One sump,
|
160 gallons | 605 liter |
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Base addition tank,
|
55 gallons | 208 liter |
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Total water volume
|
29,000 gallons | 110,000 liter |
| Land area | 1/8th acre | .0.05 hectare |
Tilapia harvest of one rearing tank occurs every 6 weeks. Stocking is staggered to achieve a fairly consistent input of feed. Tilapia fingerlings are stocked at about 2 oz. (50 g) size and reared for 24 weeks to 2 lbs. (900 g).
CAS rearing tanks are shaded to reduce algae growth, keep the water cool and provide subdued light to the fish. The tanks are aerated with diffused air. Water is pumped continuously through the tank at a rate of 25 gallons/minute (100 l/min) providing a full volume exchange every 1:20 hrs.
Water leaving the rearing tanks moves through clarifiers and net filter tanks for removal of all solid waste.
A variety of vegetables can be grown in the hydroponic tanks. Leafy greens are highly recommended because of their close planting density, short growth period and frequent harvest. Fruiting crops are also productive but require more water quality management.
