Water Use Efficiency in Hydroponics and Aquaponics

Posted by Perry Baptista on June 4, 2014

Water conservation an increasing concern

faucet-576755_1280Especially in the drought-ridden west, water conservation is a topic of increasing concern. You've recently heard about water in the news, across social media, and among friends - not just from farmers. Drought conditions and lack of water impacts agriculturalists, municipalities, industries, and individuals.

So how can hydroponic and aquaponic systems reduce water loss, increase water use efficiency, and use water more sustainably?

Typical water loss in aquaponics and hydroponics

In most hydroponic farming systems, water is recirculated. Run-off water that is not taken up by the plants is recaptured. Nutrients are constantly added by fish waste or fertilizer, and water returns to the plants. Every bit of water is reused over and over again, an impossibility in traditional, soil-based agriculture. 

Since it is recirculated and recycled, water is never discharged in hydroponics or aquaponics. Water loss occurs in two main ways:

1) Evapo-transpiration

Evapo-transpiration is the use and evaporation of water through the plants. There is no way to eliminate evapo-transpiration; it is a necessary function of living plants! You can, however, keep it as efficient as biologically possible by making sure that your temperature range is suitable for the crops you are growing.

2) Leaks

Leaks sometimes form in the greenhouse irrigation system. This might be a broken pipe or split tubing, but it's most likely that a dripper has been displaced or a leaf is redirecting the water flow. Careful and frequent monitoring of the system is the best way to identify leaks. We walk through our green house three times a day to check for leaks, then make repairs as quickly as possible.

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Total water loss in our system

Altogether, total water loss in Bright Agrotech's aquaponic system, using ZipGrow Towers, is only 1.5% per day. Other leading hydroponic system competitors have water losses of 7% per day. The difference from traditional systems is hardly comparable.

 

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Water loss in traditional systems

Traditional gardening requires 20 times the water use of a recirculating system. Why is that? Agricultural flood irrigation in large fields loses water to simple evaporation, run-off, and dispersion beyond the reach of plant roots. The agricultural industry is changing its practices to be more water-wise, but even the best drip irrigation only cuts flood irrigation losses by about one-fourth, nothing close to hydroponics.

Water for ZipGrow tower systems

At Bright Agrotech's farm, we run a 4,000 gallon system with a little over 200 towers. We replace 40 - 60 gallons of water each day due to loss.

Water needs for your ZipGrow tower system depend on whether you are a hydroponics or aquaponics producer. Scaling of needs as system size increases is fairly constant.

Dig Deeper >> Learn More About Flow Rates in ZipGrow Towers

 

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Hydroponic water requirements

For a hydroponic system, plan for a 50 gallon sump plus an additional 1 gallon of water per ZipGrow Tower. (For a 200-tower hydroponics system, plan for 250 gallons of water.)

Hydroponics sump size (in gallons) = 50 gallons + (# towers * 1 gallon)

Aquaponic water requirements

Aquaponic systems have slightly more complicated water requirements. For each pound of mature fish, allow 8-10 gallons of water. Each linear foot of tower requires 0.3 - 0.5 lbs. of fish. For each 5-foot ZipGrow tower in the system, plan for approximately 2.5 lbs of fish and 20-25 gallons of water. (A 200-tower system, then, would require 4000-5000 gallons of water._

Aquaponics sump size (in gallons) = (lbs. of fish)*(8 - 10 gallons)

Lbs. of fish = (# towers)*(tower size, in feet)*(0.3 - 0.5 lbs.)

Concerned about water conservation? Try ZipGrow.

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Water use efficiency in a hydroponic system using ZipGrow Towers is drastically lower than that of traditional agriculture and other leading competitors, with only 1.5% water loss. This not only lowers water bills, but allows water to be used much more sustainably.

As you learn more about ZipGrow, think about the kind of farm that you want to run. Is water conservation important to you? Then choose equipment that allows you to accomplish that goal.

 

Topics: Setup & Plumbing

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