Aquaponics appears to be the world’s most productive food system in terms of water use efficiency.
That can be expected to be a political ace for aquaponics science and technology as the world’s fresh water supplies come under increasing pressure.
Depending on where it is practiced, much aquaponics takes only about half the volume of water to produce $100 worth of food in the form of fresh fish and fresh vegetables or fruit – whatever the currency – than inorganic hydroponics.
The best Recirculating Aquaculture Systems (RAS) generally use around 700 to 800 liters of water for about $100 worth of food.
But add organic hydroponics as a “back-end” to grow food plants from fish wastes, and there’s an immediate reduction in water use as waters from fish tanks are cleaned and recycled back to these tanks. This is the key to why aquaponics is such an efficient system.
It is “Mother Nature” at work – where, over countless millennia, the wastes of one process have become the raw materials of the next.
Bumbling humans are only just discovering the great good sense of linked polycultures such as those in aquaponics – instead of using monocultures that gobble up water, fossil-fuel energy and nutrient resources (mostly created from, or using, fossil energy).
I predict that, with increasing awareness of the advantages of aquaponics and hydroponics in political circles, where the painful economics of water use allocations are being thrashed out in many countries, there will be a very logical favoring of aquaponics and hydroponics development.
My other prediction is that this miserly water use, combined with small space needs in cities, will make urban aquaponics and hydroponics the dominant food security technologies that will emerge from this century of humankind’s development.
Small signs of this can be seen already among intensive aquaculture producers who are able to harvest fish wastes for additional profit rather than send them down drains at a cost – or not at all as environmental protection laws continue to tighten. Further signs are evident in the advances being made in hydroponics, especially close to city markets, or within cities.
“For tilapia/lettuce it is 210 liters per US$100, and for tilapia/basil it is 85 liters per US$100.
He explained: “I took the total revenue generated from the tilapia/lettuce and tilapia/basil enterprise budgets and divided this by US$100 to the get the total number of US$100 units.”
“I then took the initial system volume (110 cubic meters) plus the annual daily makeup water (0.015 x 110,000 liters x 365 days). This came out to 712,250 liters. I then divided this by the number of US$100 units.”
But even a most conservative calculation of water use to revenue earned comes up with figures that are as impressive as the best inorganic hydroponics. The aquaponics figures are extremely variable and will fluctuate wildly according to species of fish and food plants chosen.
All that can really be said is that aquaponics can be expected to be the most miserly user of water to grow food in most practical circumstances. Hydroponics is nearly as good – and is well proven.
For more indoor,outdoor, and hydroponics information, please visit San Diego Hydroponics & Organics website.