Aquaponics - sustainable foodweb connecting fish to the land

I have been designing an aquaponics system for small business in which I have come across a few problems.  One of the more obvious it the problem of introducing biomass into a closed loop system.  The problem is that fish pellets (which are popular in aquaponics) are not sustainable!  Many brands are made of dehydrated chicken scraps, so called junk fish (especially ones processed for omega-3), algae, amoung others.  I need extensive incite on how to generate food where I am limited to a 100 acre setting, I am incorporating agroforestry/rotational grazing into the equation so I would love some here-say solutions.  The fish species I am leaning towards is tilapia because I love the taste and they are a reliable species.  Also I am looking into Malaysian prawn.  I have even gone as far as looking into insect traps to trap them as a food source.  My desire is to develop all resources internally so again your incite and suggestions are greatly appreciated.

I found a video that was inspiring, it is a aquaculture/permaculture farm is Spain, but in my area this is not an option because of the gigantic land mass requirement and I was looking into the benefits of growing aquaponic produce. 

For fish who like to eat bugs, there's Black Soldier Fly larvae:

http://blacksoldierflyblog.com/

Also crickets, mealworms, and red wigglers, all of which are domesticated and raised commercially.  There may be an initial investment in proper housing for these critters.

http://www.wormman.com/breeding_crickets.cfm


All these critters will eat "waste" products from other parts of the permaculture operation.

The Circle of Life! 


Tilapia also eat various aquatic plants such as duckweed, as well as some garden vegetables, apparently.

some people hang rotting meat or other things over their ponds so that the "bugs" fall off into the water and feed the fish, others plant certain plants overhanging the banks so that the fruits of those plants fall into the water, but it would depend on what the fish would eat.

there are also floating islands that you can create that have roots that go into the water and feed your fish..basically it is a screen with flotation devices and planted on the screen in the water.

there are also fish food plants that you can put in your ponds, see LIlypons and Trickers for some ideas.

What region are you in?  100 acres seems like enough space to harvest a lot of fish food, how much fish are you planning to grow?
I haven't raised tilapia, but I was involved in the development of a system that now stocks them.  My understanding is that they don't require lots of high protein food, and work well with other species, as they will eat detritus, water plants, and algae, keeping the system clean for the companion species.  The system I worked with now stocks crayfish, fresh water mussels, and bass along with the tilapia.

I'd love to hear more...

peace

Osker, I live in Piedmont NC and would love some details on your system.  How and what purpose do fresh water mussels serve.  One interest I have glanced at was black soldier fly larva, but I would have to produce hundreds of pounds at a time so I will check your link out.  Floating islands sounds interesting, but I do not want those plants to compete with the humus availability in the aquaponics setup.  I wish I could grow the feed, but something that is healthy for the fish and not some filler crop like corn.  I have even looked into making my own pellet feed.

We butcher a lot of animals (sheep mainly) and I am thinking of taking our huge pot we use for rendering pig fat and using it to cook up the innards and waste (over a wood fire so it doesn't cost anything) and turning that into catfish food. I could feed it raw to the catfish, but I am just not sure of the consequences to the plants. Not worried about the fish, they live on raw butcher waste in the pound (would you believe 5 lb catfish after 2 years?!)

We also have langostinos here, which are fresh water lobster, about 12 inches long. They work really well in an aquaponics system.

Amedean wrote:
I do not want those plants to compete with the humus availability in the aquaponics setup. 

I'm not sure what you mean by "humus availability" as there is no humus in an aquaponics system, to my knowledge.  Do you mean nutrients?  What plants do you intend to grow in your aquaponics system?  If lettuce and other greens there will probably be an amount of damaged leaves which could be fed to the fish.

Actually, there is humus in the water of all working aquaponic systems, but your right in my oversimplification because there is more to the biochemistry.  Humus is basically stabilized organic mater and is formed in any process of decomposition.  Minerals can be found bonded in this inert organic mater and they are also water soluble.

http://en.wikipedia.org/wiki/Humus

Without humus, you cannot grow any plants.  You get humic material when bacteria break down organic mater into its stabilized basic compounds.  This is main reason you need bacteria in soil and the same goes for water.  If you have organic mater in a steril environment, it will not decompose.

Humic materials are found in soils, natural waters, sewage, marine and lake sediments, compost heaps, peat bogs, lignites, brown coals, and miscellaneous other deposits. Their abundance in soils is two to three times higher as compared to the living mass of organic matter. Humus are operationally classified based on aqueous solubility into three major fractions: humic acids, fulvic acids, and humins.



In aquaponics, you cannot simply dump loads of humus because it messes with the water chemistry of the fish - that is done in hydroponics.  Fish eat biomass which bacteria break down eventually into humus among other things.  This is very generalized but they have classes in this and the field of study is called soil science.  I am no expert or claim to be because this is really complicated stuff, I just brushed up on the basics

Ok thanks.    I hope you'll build a small test system before you jump into an enormous investment.  My little system is being a challenge, even as small as it is.  And I'm not much on theory, I have to admit, I understand practical hands-on stuff much more than some chemical diagrams....

The beneficial bacteria in aquaponics mainly reside on the growbed media, as far as I know, and not so much in the water. 

Yeah, dont forget to fill me in on those tigernuts

Amedean wrote:
In aquaponics, you cannot simply dump loads of humus because it messes with the water chemistry of the fish - that is done in hydroponics.  Fish eat biomass which bacteria break down eventually into humus among other things.  This is very generalized but they have classes in this and the field of study is called soil science.  I am no expert or claim to be because this is really complicated stuff, I just brushed up on the basics

I think you aren't saying this right, or are missing something (and just so you know, I have had a 3,000 liter system. The purpose of the system is mainly to clean the urea from the water, and the waste of the fish, so they can continue in the same water. There are two processes, that change the urea into something the fish can use.

The humus is a serious problem for everyone I know, because fish to have solid waste, this tends to build up. Many people I know clean their gravel on occasion, so that the water continues to flow (after harvest, for example) I know in my system, eventually I had to clean out the gravel. Some even have earthworms in their system, it gets so bad.

The problem is, you get to much organic matter, the bacteria start shutting down, due to not enough water moving through, and draining, in the system.

Take a look at backyardaquaponics sometime, I did a lot of reading at one time, and never saw a discussion about humus, except to curse it. Not saying it wasn't there, but I can tell you that if you drop a bunch of fish in, and start feeding in, in just a couple of days, you can start planting. (you check you PH  to make sure that the two processes of conversion are working) I started same day, but I used pond water to start, not tap water - which as the bacteria which is required.

A lot of people put in the plants before they add fish, providing nutrients for the plants with pee-ponics or compost tea, etc.

H Ludi Tyler wrote:
A lot of people put in the plants before they add fish, providing nutrients for the plants with pee-ponics or compost tea, etc.

pee-ponics, I believe, will require the same bacteria. Compost tea, wouldn't.

Honestly, you can make this all way too complicated. It is a natural process and occurs in nature all the time. One thing you do have to watch out for is water PH.

Fred, setting up an aquaponics system is not something most people can just walk into.  Because it occurs naturally does in no way shape or form mean it is simple.  I could be wrong though, you could be one of those few people who have actually set up a system with initial success.  If you are one of those please upload some pictures and share with us your details.  With this said, I know Ludi is getting some experience with a system of her own and it is difficult initially.

Another note, you are confusing solid waist (humin) with water soluble humus.  But you are correct in that I could have worded myself more efficiently in explaining the chemistry of the water when adding an arbitrary amount of humus and other nutrients.  So with this said, in hydroponic systems, the water chemistry is not designed to accommodate fish as nutrients are provided - I do not want to go into details on this because it is lengthy to explain. 

What? If you are doing one of the standard designs (tried thousands of times), it's relatively foolproof.

The simplest design is to have:

grow bed volume = fish tank volume
grow bed filled with hydroton or river-rock gravel
no more than 1 lb of fish (adult size) per gallon of fish tank
pump turns on and off once an hour, and pumps at least the whole volume of the fish tank in that one cycle
grow bed drains back to fish tank with a stand-pipe

During the spring or summer fill the system, put in a few goldfish to kick the system into gear, wait a month (feeding fish along the way), add more fish and plants.

Obviously there are infinite variations to this, and you can completely geek out on NH4/NO2/NO3/DO/TDS levels. But the basics totally work.

I was wondering the same thing about the solids which would eventually accumulate in the fish tank and in the grow beds. Some people have established worms in the growbeds but that doesn't seem to address the fish tank. Also, I have read that even so eventually you have to clean or replace the medium in the grow beds.

What I am looking at (as well as worms in the beds) is having a sloped v shaped drain  on the bottom of the tank which can  be drained from time to time into a biomass system to produce methane..(other stuff could be added to the fish tank slurry in the digester). Any  experience or opinions on this? I am planning on a pretty big system..about 1200 gallons, so what to do about this stuff is something I want to have a handle on before getting into it too far.

Amedean wrote:
Fred, setting up an aquaponics system is not something most people can just walk into.  Because it occurs naturally does in no way shape or form mean it is simple.  I could be wrong though, you could be one of those few people who have actually set up a system with initial success.  If you are one of those please upload some pictures and share with us your details.  With this said, I know Ludi is getting some experience with a system of her own and it is difficult initially.

Another note, you are confusing solid waist (humin) with water soluble humus.  But you are correct in that I could have worded myself more efficiently in explaining the chemistry of the water when adding an arbitrary amount of humus and other nutrients.  So with this said, in hydroponic systems, the water chemistry is not designed to accommodate fish as nutrients are provided - I do not want to go into details on this because it is lengthy to explain. 

Yes, I did it first time, and it went just fine. Then again, I am an engineer. Lots of people have had success the first time, but you have to be attentive.

The biggest difference in hydroponic, conceptually, is that a hydroponic system you add the nutrients for the plants. In an aquaponic system, you feed the fish (or whatever you are using) and THEY feed the plants.

Neal McSpadden wrote:
What? If you are doing one of the standard designs (tried thousands of times), it's relatively foolproof.

The simplest design is to have:

grow bed volume = fish tank volume
grow bed filled with hydroton or river-rock gravel
no more than 1 lb of fish (adult size) per gallon of fish tank
pump turns on and off once an hour, and pumps at least the whole volume of the fish tank in that one cycle
grow bed drains back to fish tank with a stand-pipe

During the spring or summer fill the system, put in a few goldfish to kick the system into gear, wait a month (feeding fish along the way), add more fish and plants.

Obviously there are infinite variations to this, and you can completely geek out on NH4/NO2/NO3/DO/TDS levels. But the basics totally work.

Yeah, plenty of off the shelf systems now. What I would recommend is NOT doing auto-siphons when you start (flood and drain like you are describing is great) unless you want to take up drinking...

Pam wrote:
I was wondering the same thing about the solids which would eventually accumulate in the fish tank and in the grow beds. Some people have established worms in the growbeds but that doesn't seem to address the fish tank. Also, I have read that even so eventually you have to clean or replace the medium in the grow beds.

What I am looking at (as well as worms in the beds) is having a sloped v shaped drain  on the bottom of the tank which can  be drained from time to time into a biomass system to produce methane..(other stuff could be added to the fish tank slurry in the digester). Any  experience or opinions on this? I am planning on a pretty big system..about 1200 gallons, so what to do about this stuff is something I want to have a handle on before getting into it too far.

I'm assuming you aren't doing a raft or NFT system here...

Ideally, your system will evacuate solids from the bottom through your pumping action. They may literally go through the pump or be pushed through the overflow tube (which is better than pumping directly). Once in the grow beds, the bacteria will break down your solids.

You should never need to clean your growbeds. If you do, you have too many fish for your growbed. Adding worms to the growbeds does increase the carrying capacity of the growbed, so a lot of people like to use them for speed and insurance.

If you are doing a media-filled growbed system, you shouldn't need to ever clean it (again, unless you are overstocked).

Check out my simple aquaponics system overview: http://www.youtube.com/watch?v=tea8knevRQI

I made it to help out AP newbies understand how the pieces fit together. It can be scaled to any size so long as the grow beds are within 1x - 2x the fish tank volume.

well  thanks for your input..it doesn't quite sync with what I have found on other sites which have somewhat larger set ups than what you are showing. The consensus there has been that there will always be a buildup over time in both the fishtanks and the growbeds, and  worms will help keep things cleaner for quite a while but not for forever.

Also, I don't intend to have the pump in the fishtank, just in case something goes wrong; it will be an overflow system and the water will be pumped out of the sump into the fishtank which will then force the water out of the fishtank  to the growbeds.  That way I won't ever have to worry about coming in and finding that the return system  went wonky somehow and I have a bunch of dead fish in a dry fishtank. Gravity isn't likely to fail anytime soon and if the pump blows out then the plants won't get their drink but at least the fish will survive. However, that also means that much of the solids that have settled to the bottom of the fishtank will stay there and eventually need to have something done about them.

I agree with Pam about the pump in a sump tank being safer for the fish.

If you have a Solids Lifting Overflow Siphon on your fish tank, this will help pull the solids out of the fish tank, but they may eventually reside in the sump tank.  So far there hasn't been much in the way of solids in my sump; the pump seems to be moving them into the filter bed/worm bed pretty well.

@ Neal - I am not making a standard design.  It is not entirely unique either, but it is definitely not standard.  Personally, I do not agree that aquaponics is fool proof unless you have a lower standard then amazing or damn good!

@ Fred - your an engineer, awesome!  I'm in engineering school right now but anyways back to the subject.....

When it comes to tilapia or prawn for my system, what can I grow that:

[li]can be grown in a small farm/small business[/li]
[li]allows me to provide large enough quantities of nutrient sufficient food[/li]

I might have to order a book on exploring the dietary options but I was hoping for some good links with a similar setup.  My goal is to be almost completely self efficient.  As I had explained earlier, I have not seen a truly sustainable food web connecting the readily available biomass from the land to the aquaponic system. 

Fish pellets are not sustainable and they are expensive.  I have the option of making my own fish pellets, but what do I use?  My intention is to grow a crops as well, so I have to consider that there has to be enough biomass to support a profitable business. 

I'm attracted to aquaponics because:

[li]time is valuable, I do not need to plant cover crops to recover the soil[/li]
[li]water transports heat which is needed here to have year round production here (zone 7-[/li]
[li]I hate bending over , I am not a resilient field farmer[/li]
[li]less disease and greater crop consistency[/li]

Plenty of folks on Backyard Aquaponics have had major fish kills, like wheelbarrows full of fish who died at nearly harvesting size, due to some aspect of the system becoming unbalanced, so, I'm of the opinion it is not as instantly simple and easy for everyone as it may be for a few.  Like the proverbial "green thumb" some people may have a "fish thumb."  I do not personally have a green thumb, so I sure hope I'll have a fish thumb!    

http://backyardaquaponics.com/forum/index.php

Some systems in India producing fish and freshwater prawns:

Inland fish farming (in Kerala, India, long video, excellent)
http://www.youtube.com/watch?v=w9dH8WCJIGc&feature=related

This video covers pond construction and maintenance, raising of seedling fish, culture and feeding of fish, harvest (nets, draining ponds), raising fresh water ponds, food cropping and integration of ducks into an agricultural system. This is one of over a dozen videos by this group, well worth viewing.

The author, KissanKerala's, YouTube page, a good place to start viewing the collection.
http://www.youtube.com/user/kissankerala

As well as Backyard Aquaponics another source of info I am depending heavilly on is run by Murray Hallam out of Australia.    One of the comments I have seen on one or the other is the concern that people are led to believe that this is an easy quick and foolproof thing to do..which it CAN be but things can also go  drastically wrong very easilly and not always for a readilly obvious reason.  

I have been researching what people who have just aquariums feed.. there's daphne and crickets and brine shrimp and so forth..one thing I have been looking at for summertime production, drying some of it for the long winter...is an algae also used for human nutrition, spirulina  It needs lots of warmth though so no good for here.

Seems as though a mix of things is best...and will depend to some degree on what fish you are raising.         anyway, here's the Hallam site
http://www.aquaponics.net.au/forum/