Aquaponics

[SMO]

I have begun to construct an aquaponics system which is a possible solution to a whole host of problems, traditional farming, space, transport, processing, preserving of fruits and vegetables.
The basic idea is that you have two tanks, one below and one above. The below tank has fish (that you must feed) the top tank is filled with clay pebbles of sorts. Water is run through a filter constantly cycling through the bottom tank up to the top tank. Vegetables, plants and herbs can be grown in the top tank as the waste from the fish becomes nutrition for the plants and the plants don't have to work as hard to get the nutrients they are delivered. This shortens the growing season the plants are grown inside a greenhouse so they do not need pesticides or dirt. The fish are able to be eaten once they reach a certain size.
Do you think this is a viable alternative to large scale commercial farming in the traditional sense?

 

[Ex-User (5841)]

Theoretically you should be able to create a self-sustaining system where you no longer need to feed the fish because the whole thing not only stands on it's own primary productivity, but produces surplus that can be harvested from all levels (you may need to add more trophic levels, e.g. aquatic macroinvertebrates to consume leaf litter and serve as fish food, as well as transporting additional nutrients from aquatic to terrestrial, as is the case for mayflies).

However, this has already been done with extreme efficiency. We ecologists call this nature. Cruel yet hilarious, eh?

Do you think this is a viable alternative to large scale commercial farming in the traditional sense?

^Permaculture, preferably with native species.

 

[SMO]

Well this particular one will be a mixture of technology and nature, I suppose.
(That picture is not the one I am building by the way, that is just an example of a aquaponic bed.)
This one will not have natural food (i.e. mayflies) , I will be using fish food as it will be in a greenhouse that will hopefully be able to produce all year long. These beds could be set up in neighborhoods as well as larger commercial operations, the downside is the water pump must continuously run and the environment has to be regulated.


I could be wrong though, I thought for certain that hydrogen powered cars were the solution to fossil fuels and they have yet to make a dent in the automobile industry.

 

[Ex-User (5841)]

The downside is the water pump must continuously run and the environment has to be regulated.

Or does it? You may want to populate the water with specific algal cultures that raise dissolved O2 and serve as a supplimentary food source, provide shade to keep temps lower which further increases dissolved O2, and hook it up to a rain gutter flow-through system so that there is an influx of both oxygenated water and nutrients.

For fish: when in doubt, go for tilapia. Just NEVER release them into the wild (gotta remember to say that nowadays).

I'll come back to this later.

 

[SMO]

Or does it? You may want to populate the water with specific algal cultures that raise dissolved O2 and serve as a supplimentary food source, provide shade to keep temps lower which further increases dissolved O2, and hook it up to a rain gutter flow-through system so that there is an influx of both oxygenated water and nutrients.

For fish: when in doubt, go for tilapia. Just NEVER release them into the wild (gotta remember to say that nowadays).

I'll come back to this later.

This is very interesting to me, please elaborate when you get the chance.

 

[SMO]

Here is a simple picture of the set up and how the pump pulls waste and water from the bottom of the fish tank, pumps it into the garden bed and the water that "overflows" will drain back into the fish tank.
One issue I did notice with another set up is that the plants grow so quickly that the fruit will break the stems as the fruit grows large very quickly and compromises the structural integrity of the stalk or stem, essentially "outgrowing the stem".

 

[Kuu]

Why aquaponics instead of aeroponics? As far as I understand it aeroponics is the ultimate in resource efficiency. Ease of construction, money...?

 

[Ex-User (5841)]

This is very interesting to me, please elaborate when you get the chance.

Here we go:

Spoiler

This theoretically uses the increased gas pressure inside the greenhouse due to the greenhouse effect, plus influx from a gutter on the greenhouse roof to:

1. circulate the water
2. aerate the water to keep the fish kic... swimming
3. circulate the air
4. reduce cost



It's based on the idea of an airlift pump, but just uses simple air pressure inside the greenhouse to operate. This should compensate for dissolved O2 loss during the day, when O2 levels are lowest. Fish need at least 5% dissolved O2 to avoid being belly up.

On top of that, the 55 gal rain barrel (which should be kept cool and shaded 24/7 to maintain dissolved O2 integrity) provides new water influx that further replenishes dissolved O2 every time it rains, as well as forcing more nutrient-loaded water out of the outflow, which goes to the plants/crop. This could simply be standard drip irrigation/"fertigation".

The crux of the system is the cool air intake, which should be a shady area outside at just above ground level. Avoid using a covered pit because you'll get more CO2 (higher density) than O2.

The yellow X is just a standard valve to allow backflushing in case sediment clogs the water outflow.



The duckweed is added because:

1. it provides shade that reduces algae (eliminating the risk of algae blooms) and increases dissolved O2 levels
2. it serves as a high protein supplimentary fish food
3. it will help stabilize nitrate levels

Tilapia or carp would be preferred fish species because they're tolerant to conditions that would kill other, more sensitive species. Low dissolved O2, high nitrates, high turbidity, low sunlight, etc. And although these species would normally accumulate toxins in a natural environment, this system is largely cut off from such toxins so eating them is no problem. For example, these fish species are frequently used in aquaculture in the sahel of the Sahara Desert.



Am I an asset yet?

 

[Ex-User (5841)]

Permaculture is still by far more efficient.

 

[SMO]

Why aquaponics instead of aeroponics? As far as I understand it aeroponics is the ultimate in resource efficiency. Ease of construction, money...?

From what I can determine the aeroponics is a bit more sensitive and complex in structure. This is experimental for me so I will have to do so more research on the aeroponics set up.

 

[SMO]

Here we go:

Spoiler

This theoretically uses the increased gas pressure inside the greenhouse due to the greenhouse effect, plus influx from a gutter on the greenhouse roof to:

1. circulate the water
2. aerate the water to keep the fish kic... swimming
3. circulate the air
4. reduce cost



It's based on the idea of an airlift pump, but just uses simple air pressure inside the greenhouse to operate. This should compensate for dissolved O2 loss during the day, when O2 levels are lowest. Fish need at least 5% dissolved O2 to avoid being belly up.

On top of that, the 55 gal rain barrel (which should be kept cool and shaded 24/7 to maintain dissolved O2 integrity) provides new water influx that further replenishes dissolved O2 every time it rains, as well as forcing more nutrient-loaded water out of the outflow, which goes to the plants/crop. This could simply be standard drip irrigation/"fertigation".

The crux of the system is the cool air intake, which should be a shady area outside at just above ground level. Avoid using a covered pit because you'll get more CO2 (higher density) than O2.

The yellow X is just a standard valve to allow backflushing in case sediment clogs the water outflow.



The duckweed is added because:

1. it provides shade that reduces algae (eliminating the risk of algae blooms) and increases dissolved O2 levels
2. it serves as a high protein supplimentary fish food
3. it will help stabilize nitrate levels

Tilapia or carp would be preferred fish species because they're tolerant to conditions that would kill other, more sensitive species. Low dissolved O2, high nitrates, high turbidity, low sunlight, etc. And although these species would normally accumulate toxins in a natural environment, this system is largely cut off from such toxins so eating them is no problem. For example, these fish species are frequently used in aquaculture in the sahel of the Sahara Desert.



Am I an asset yet?

That is great, let me look at the design for a while, I certain I will have some questions.
What is the solution for long periods of no rain?
Do you have any thoughts on designing a feature on the roof of the greenhouse that would create condensation which could off set some of the evaporation?

 

[Ex-User (5841)]

That is great, let me look at the design for a while, I certain I will have some questions.
What is the solution for long periods of no rain?

As for KY, you typically get 44 inches of rain min. annually, so no worries. This clearly isn't something to put out in the middle of the Sonoran Desert

The greenhouse itself is close to a closed system as far as water goes. There will be some optimum size as far as the roof surface area required to collect X amount of water goes, and there would also be an optimum size/depth for the pond itself so that it can function as a reservoir if the circumstances call for it.

This system is ultimately self-irrigating, not necessarily hydroponic, meaning that a substrate finer than clay pebbles is likely more suitable. It also avoids eutrophication in the fish tank/pond by using a longer circulation that would allow more efficient microbial digestion.

In urban environments rooftops aren't a limiting factor, and it'd be nothing to ditch the 55 gal barrel for multiple barrels or a storage bladder. If done right (the water in storage plus in the pond is kept cool and shaded by say... plant trays... or duckweed) dissolved O2 conc. shouldn't depend on rain. Temperature control can also be facilitated by excavating.

Do you have any thoughts on designing a feature on the roof of the greenhouse that would create condensation which could off set some of the evaporation?

Because the system is almost closed re: water, the condensation would merely drip off and re-evaporate, cycling 24/7. Not much can happen past the point where the air is simply saturated with water vapor. Additionally you could expect condensation to occur near the cold air intake and more likely on the sides and in shaded areas than the roof. Ideally this should be located near the rain barrel so that a small collection mechanism can be set up there. If anything, high humidity increased air pressure and oxygenates the water more while letting comparatively less humidity escape through the air outflow.

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