Thursday, October 25, 2012

The Perfect System

Originally I posted this to show the tank arraignment, but then added temperature control, green house design, and lighting.  I feel these are the best ways to design an aquaponics system.

But aquaponics may not be the best way to grow food.   Fish are, as Vlad put it, "a romantic attraction", but most will agree that it complicates the process.  Raising fish does not provide fish at a lower cost than current retail grocery store prices, and conditions such as temperature, and pH in the vegetable garden are often comprised

Peeponics, or Bioponics require no food, or comprises, and allows you to concentrate your efforts on growing vegetables.  Without fish poo to clog up the system, the plant roots will remain clean and healthy.  Without the overhead of fish food the cost of your vegetables will be lower.  Plants require less temperature control.  The list goes on.  We produce urine every day - sadly it's a wasted resource.

I highly recommend reading this PDF about Aquaponic design.  It is without a doubt one of the best papers I've ever read.  I wish I had followed the advice presented from the beginning.  But the school of hard knocks is often required before we come around to a full understanding of the gems available to us .   http://www.backyardaquaponics.com/Travis/Aquaponics-Design.pdf


Like I said  'Optimization of Backyard Aquaponics for Food Production'.  is one of the best documents I've read.   I read that paper carefully taking note of the calculations involved, and created a spreadsheet to help with the design of a system.

The spreadsheet is available at
 https://dl.dropboxusercontent.com/u/20676945/OPTIMIZATION%20OF%20A%20BACKYARD%20AQUAPONIC-v2.ods


What follows below is the best of everything I've learned.  Apply it to either Bioponics,or Aquaponics.   


The Perfect Back Yard  System combines the Sump and Raft


Here is a link to

Murray visits the USA teaching Commercial Aquaponics


Tanks & Pumps

This system can be sized up as shown here.  But if you are a beginning aquapon I suggest starting small with a system like the one Murray is standing next to.  The independent media beds allow maintenance on one while the others remain undisturbed.  The large sump tank prevents radical water level changes and the grow beds placed at the same level as the sump simply circulate water through a series of rafts returning water back to the sump.  Only a very small 30 GPH pump is required because there is no head pressure.  30 GPH is extremely low flow, but this has proven to be all that is required, even in very large rafts.  Click this link for a very interesting video!   To use an airlift pump the sump tank would have to be deeper than shown here.  Airlift pumps appeal to me because they aerate while moving water and blowers are far more reliable then water pumps.

OPEN THIS DRAWING WITH SKETCHUP

A geyser pump, an improved airlift pump
An Airlift Pump Spreadsheet is available at airlift_basic_calculation.xls
Multiple fish tanks allow you to raise generations separately and cull the runts from each generation.

There are no filters to clean,  Passing the water through the media beds cleans the water coming from the fish tank.  Vermiculture is used to keep the media clean.  Using a Timed Flood and Drain system will save utility costs and avoid the problems associated with bell siphons.

Enlarging the system as shown here would require two pumps but one will be used intermittently to pump water from the sump to the fish tanks.  The other will be a very small pump which will be very inexpensive to run.   

Overall this system satisfies all the requirements of a reliable, low maintenance,  and low energy system.  Periodically the drip holes would need to be cleaned, and of course water tests and feeding.  But that's about all there is once the system is established.  

The drip holes are not located on the stand pipe as you might imagine, but rather on a 1" pipe connected through the side near the bottom of the media bed.  This allows for easy access and periodic cleaning.  It also places it where you can see the weep holes, and be aware of any developing problems.  Using a Uniseal at this connection also allows the pipe to be removed easily if deeper maintenance is required.

An Aquaponic Valve is a mechanical indexing valve... there are no electrical components.  While this could be used to sequence the Flood & Drain of each media bed to further prevent water fluctuations in the sump, and raft tanks, this is not required due to the total volume of the sump and raft tanks. 
Here's another DIY Indexing Value built and designed by Rob Torcellini

There has been some research with aerobic rafts the called GW Raft system.  I would like to incorporate a simpler version of that by placing boards with net pot holes over the top edge of each raft.  The water can be adjusted by the length of the stand pipe.

The height of the water could be adjusted higher with the stand pipe to allow the net pot to wick.  As the roots grow the level can then be adjusted lowed to provide the air space.


To gain even better flow with the air pump I have designed this system 



...Download this Sketchup Model..

This system has two radial filters and a media bed to keep the deep water culture raft very clean, An air pump keeps the water moving via an air compressor; no mechanical pumps are required. Water levels in all the tanks are the same. By not raising the water from a sump tank only a small amount of energy is required.
This is how my system is set up.  Everything in one tank.  Pots are placed on the platform suspended just below the water and wick the moisture up.  The fish swim underneath.
I currently use a 6" airlift pump to circulate the water in the fish tank, but I'm working on adding a 45" deep tube through the bottom, so that I can get a real good flow.  I'll post pictures when that is finished.

Garden Enclosure

One additional note about making this perfect is the need for a green house.  An efficient green house can be built if insulted well on three sides and glazed on the south.  My experiments have shown that the Summer temperatures will not get too hot.   Enclosed growing spaces require ample air exchange.  Mold and insects can become a major problem over night. I highly suggest making a option to open the enclosure.

Temperature Control 

 

http://tcpermaculture.blogspot.com/2011/09/rocket-mass-heater.html

 

My research into Rocket Mass Stoves has lead me to believe Winter heating can be accomplished without added utility.

Solar is also an option.  This system was built and documented by Paul at Gardening Rhythms.

Lighting

Supplemental lighting will be required in the Winter only because of the short days.  But Ceramic Metal Halide can provide efficient full spectrum lighting at a reasonable cost.

Running an aquaponic system may seem simple at first glance.  Feed the fish and grow perfect vegatables.  Don't be fooled by the simple appearance of these systems.  Read "Integrating Fish and Plant Culture" first.  Take note of the complex chemistry described in the section "Nutrient dynamics".  This is one of  the best and most comprehensive articles I've ever found.

2 comments:

  1. Nice system design Bob! Would you expand on what an 'aquaponic valve' is? Also, which tanks are sump and which are fish?

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  2. The fish tanks are the two large cubes by the lady. The sump and rafts are blue water.
    The dirty fish water overflows from the fish tanks into the media beds (brown pipe)
    Then the filtered water drips into the sump and this clean water is passed through the rafts and back to the sump using a very small 18W pump.
    It's important to keep the raft water very clean because sludge can accumulate on the root hairs preventing oxygen uptake by the roots.
    When you lift the roots out of a raft they should be white not brown.

    An aquaponic valve will sequence the flow from one outlet to the next. This allows you to direct the overflow from the fish tank to one media bed at a time. This type of valve is used when the sump tank is too small to handle the water from all the media beds. I prefer to make keep it simple and make the sump larger.
    http://www.aquaponiclynx.com/products/aquaponic-systems-and-components/plumbing-and-valves/aquaponics-indexing-valves

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