Aquaponics - The Urban Food Revolution
by Team Treehugger, Worldwide on 12.10.07
Photo from Backyard Aquaponics.
[This is a guest-post by Gavin Leiminer. -Ed] I can’t say I’ve got a green thumb. Additionally, I haven’t ever tried to have fish as pets, let alone grow them to eat. Regardless of my pathetic self-sufficiency skills, the idea of producing my own food still appeals to me greatly. At present I’m a part owner of a solar house (I say part, as the bank manager would probably take offence to the lack of a mention), obtain water (that is heading to the sea) from a bore and have a sewerage system that processes all of the house waste. Unfortunately however, even though I live in an area of Australia that is quite productive, I can’t seem to purchase local vegetables and meat, let alone organic produce. That’s why I cannot get the idea of Aquaponics out of my head.
Aquaponics, from a layperson’s point of view, is the merging of aquaculture and hydroponics into a process that seems to take all of the positives from the above production systems and leave the negatives far behind.
Basically, the process involves fish, plants and bacteria. The cycle consists of fish by-products (or to the less delicate … ‘poo’) being pumped into grow beds filled with gravel. Bacteria convert the ammonia from the ‘fish poo’ into nitrites and then other good bacteria convert the nitrites in nitrates, which are used by the plants as nutrients. The beauty of the system is that a balance occurs in the eco-system whereby the water is sufficiently filtered by the plants who inturn obtain all the necessary nutrients from the fish.
Those that wish to avoid chemicals in the growing process, will be relieved to know that anything poisonous used on the plants, will kill the fish. This ‘canary effect’ ensures that natural, chemical-free produce is the only alternative and depending on the fish feed used, ‘organic produce’ would seem quite possible. Those with a water supply problem, will be even happier to know that aquaponics uses approximately 10% of normal farming practices. Environmentally, aquaponics also stands out as there is no effluent discharge to dispose of. Consequently, a person committing aquaponics can achieve quite a constant warm buzz, as they know exactly what they are eating, whilst conserving a great deal of water.
Aquaponics seems to have been around for a fair while, but many attribute the founding of the present incarnation to the Speraneos group in America. In Australia, aquaponics has really started to gain momentum through three very helpful websites: Backyard Aquaponics; Practical Aquaponics; and, Urban Aquaponics. A massive amount of information is available from Forum members from each site. Of particular interest, is the incredible variety and ingenuity of systems on display, ranging from MacGyver-like throw-together inventions to large-scale commercially viable systems.
Regardless of budget or location, aquaponics allows anyone to grow vegetables and fish. It might just be one part of the solution to the problem of fresh, healthy produce supply, experienced by an increasing number of people in cities through relentless global urbanisation.
::Urban Aquaponics, ::S & S AQUA Farm, ::Backyard Aquaponics, ::Practical Aquaponics
[This is a guest-post by Gavin Leiminer. -Ed]
I think you have your 'ite" and "ate" backwards. Ammonia -> nitrite -> nitrate. Most home aquarium keepers are familiar with this process. If you don't keep live plants you end up changing part of your water regularly to keep the nitrates down. If you grow plants they take up the nitrate, given enough CO2. Depending on your water chemistry, you will probably still have to add trace elements. For me CO2 is the first limiting factor, iron is the second. Plants growing in air won't have the CO2 limit, so I'd expect iron.
There is no free lunch, you still have to feed the fish. You end up with a system that turns fish food into people food, possible more calories of people food and certainly more attractive people food.
i have no doubt my own magnificant inability to grow plants combined with my amazing ability to kill fish would completely undermine any chance of my being able to do this; but, I'd love to keep my hands firmly in my pockets and see someone else's success.
this is a very cool process. . . when i rule the world, cities - those i leave intact, anyway - will be required to develop this type of 'farming' to support themselves!
I have been planning on setting up an aquaponics system for several months now. My house has a compost toilet that keeps human feces and urine out of the wastewater line. In effect the wastewater line is a greywater line. I also make sure to use natural biodegradable cleaning products. This greywater goes by gravity to a three chamber septic tank that separates the solids and greases from the water. This preliminary filtered water then goes (by gravity) into a sand filter that further filters the greywater. Then this water goes into a tertiary filter - a constructed wetland - which then further cleans out any dissolved nutrients and particles (through the processes mentioned in the posting). This clean water then goes (again by gravity) into a large artificial pond (which I have yet to finish by laying pond liner and then aquatic plants) that will act as a huge water storage tank for this recycled water (I am also planning on connecting the rainwater harvesting system to this artificial pond). Once the pond is finished, I will populate it with tenca fish, which is a common lake fish used for food in this part of Spain. I will also put smaller fish, frogs, ducks, etc. to create a somewhat 'natural' polyculture aquaculture system. And I will feed the fish with ground up grasses cut from my finca and from my constructed wetland. Once the pond is finished, I will then start work on a hydroponic greenhouse behind my house that will cylce the pond water to filter it clean and then return it to the pond. Since I live in central Spain, this does me a lot of good since water availability is an issue. I try to minimize use of water as much as possible. This system helps me to keep water use to a minimum. Helps me clean, recycle and reuse nutrients and resources in a closed loop. And will allow me to produce a huge portion of my food needs. Not to mention that the pond will provide a much needed source of water in summer for local fauna, such as birds, rabbits, squirrels, bats, wild boar, foxes, etc.
that seems like a really cool idea.
I have always wanted to try this. Thanks for the info.
Thanks JimS.
Nitrites and Nitrates have been corrected.
I have family who work on developing this type of thing for schools and prisons and other types of closed communities. They've been doing it for 15 or 20 years.
My understanding is that it's more of an industrial process than say composting. There's a fair amount of technical skill required to keep the chemical balance right, the temperatures proper etc. And I believe there's a certain scale required to make it happen. One of the reasons they targeted prisons and schools is that the technical skill required would provide job training.
In other words, it's a good thing but not as simple as growing some tomatoes in the back yard.
There are aquaponics systems of all sizes and types in existence that seem to operate acceptably - including ones for growing tomatoes in the backyard. Just look at the picture. It really isn't that complicated if you have some experience with pluming and agriculture. Unless of course you are designing huge highly automated industrial systems, which do require a lot of expertise.
I have a fantasy that supermarkets could be converted into this sort of food production. Oh yes, after the multi-national agri-business goes under and communities start taking back food production. This seems a viable way for climates other than California could be producing food during all seasons. It is a fantasy, but I love it.
I really want an aquaponics setup. I want to use the plans that Travis Hughey put together. He is a pioneer in the field.