Tuesday, November 20, 2012

"If you want to save water, grow fish."

I need to set the scene a bit for this blog post or it's importance would be easy to miss or misconstrue.

Jordanians utilize, on average, 1/10th of the amount of water used per capita in the United States. Between 70 and 75% of that water is used in agriculture for food production.  Traditional food production requires a lot of water because of substantial evaporation and seepage losses in transportation and field application.  It is reliably estimated that globally producing a kilogram (2.2 pounds) of chicken requires 4 cubic meters (m3 , 1m3 = 265 gallons) of water, a kilogram of corn requires about 1m3 of water and producing a kg of beef requires 115m3 of water.*    Some of the biggest challenges in agricultural water management are to reduce evaporation and delivery losses and to maintain natural in-stream processes for water filtration. 

*I note sources for these estimates at the bottom of the post.

What if that natural in-stream process for water filtration could be utilized with dramatically reduced seepage and evaporation losses through an on site system of reuse that had the capacity to produce significantly more food per unit of water than even modern high yield irrigation methods?  
How aquaponics works
Water is cycled from a holding tank to a fish tank where talapia are grown and the water is enriched with nitrogen and organic carbon from fish refuse.  From the fish tank water is cycled through to a garden box where a variety of vegetables and even tropical fruits can be grown year round, all housed in a polytunnel.  Fruit and vegetable root systems are supported by pumice and the abundance of highly enriched water is utilized by the plant root systems for exceptionally fast growth.  In this environment the water goes through a process called denitrification, the same process used by waste water treatment plants to clean water before releasing it into natural waterways.

The practitioners that we spoke to, Mr. Kenneth Betts and his son, estimated that in this environment growing periods for their produce would take 70% of the normal amount of time they they would normally take to mature.  Once cycled through the fruit and vegetable growing boxes the water is cycled back into a holding tank to be oxygenated and used again in the fish tanks.   

The basic math of the aquaponics operation that OpMercy's Assistant Director, Ethan Graham, and I visited near Irbid is as follows:

Annual Inputs                                     Annual Outputs
water:  100-150 m3                          800kg of fish (talapia)   
fish food:  1.5 tons                            5 Tons (4,500kg) of vegetables & tropical fruit
seeds                                                 A small amount of nitrate rich fertilizer

The numbers outlined above describe a system that is designed to produce 5kg of fish + 30kg of produce per m3 of water lost to the system.  This is a significant improvement from the global average.

Hindrances to outscaling of this technology in Jordan
The level of detail involved in maintaining this delicately balanced system is prohibitive.  It requires very consistent testing and maintenance to ensure that the system is operating at peak performance for maximum financial return. 

High initial startup costs would mean that this technology would have to be coupled with small business loans to extend opportunities to smallholder farmers who typically lack significant capital and the financial staying power needed to set up a high quality aquaponics system. 

A high level of specialized knowledge is required to set up and maintain such a system.  Water chemistry, pH, temperature, flow rate and a myriad of other technical factors heavily influence system output.  If left alone or mismanaged for even a week an entire seasons work could be lost.  Setup is highly technical requiring a strong working knowledge of everything from masonry to electronics to complex plumbing.  

Aquaponics offers very significant efficiencies in food production and income generation that Jordan could greatly benefit from.  It will be a major challenge of the farming and agricultural research community in the Middle East to integrate, on some level, these kinds of radical efficiencies as it seeks to compete in a diverse and competitive global agricultural market.   

Sources for further inquiry into aquaponics:

Sources for the global water efficiency estimates noted above:

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