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AQUAPONICS WITHOUT ELECTRICITY



In order to provide poor people with adequate protein in their diets while also allowing them to grow vegetables hydroponically, this simple aquaponics system is offered as a gift of grace from God. Aquaponics is a combination of aquaculture (Raising captive fish)and hydroponics (raising plants without soil) The challenge in practicing aquaponics without electricity is in pumping the water from the bottom of the fish tank where the manure collects. The manure is what feeds the plants in the hydroponic growing bed.

Hydroponic Production

Hydroponically grown vegetables suffer less loss from disease than those grown in the soil. They also grow faster and usually have greater production and quality. The type of hydroponic production used in this system is called "Ebb and Flow" because the growing bed is flooded with water and is then allowed to drain. This is done several times a day to keep the growing media moist so that the plants do not suffer stress from lack of water. In aquaponic production, the act of irrigating the plants also fertilizes them, since the water carries the fish manure to the media in which the plants grow. Bacteria in the growing beds decompose the manure and make the nutrients available to the plants. At the same time, the removal of the manure from the water by the growing media filters the water before it returns to the fish, preventing the decomposition of the manure inside the fish tank and therefor reducing the Oxygen levels to dangerously low levels.

Aquaculture

The fish used should preferably be Tilapia. They are disease resistant and also tolerant of relatively low Oxygen levels. They also grow rapidly, have a good feed conversion rate and begin spawning at only three months of age. This fish eatts mainly vegetable matter such as algae and chopped up leaves of edible plants. Tilapia meat tastes good and is becoming popular in many areas of the world. If Tilapia are not allowed in an area where these systems are needed, a fish with similar characteristics should be found locally.

Operation

This manual aquaponics system is made possible by a simple pump made of a piece of 8cm to 10cm (3" or 4") PVC pipe with an elbow at one end.


A 8cm piece of pipe is inserted into the elbow so that a cap can be attached to this end. Then holes are drilled into the cap so that water can flow through them into the pipe. Two pumps can be made from one section of PVC pipe. There are other hand operated pumps that can be substituted if the people have the money for them. But, if they don't, this simple device can be built at a very low price.

The cap end of this pipe is thrust into the deepest portion of the tank bottom and held there until the manure laden water in the pipe comes up to the same level as that of the tank itself. The person then places their hand over the other end to create a suction(as you would do with a pipette). Then the pipe is leaned up out of the water with the holes in the cap pushing against the water(with the cap facing away from the operator) so that none flows back out of the pipe. Continue leaning the pipe up until the water flows out the other end into the growing bed. This is repeated until the growing bed is full to the surface of the growing media.

When the bed is full the board at the far end of the bed is removed, allowing the water to flow into the algae bed. The purpose of this bed is to grow algae for the fish to eat and to remove more nutrients from the water before it flows back into the fish tank. This decreases the risk of an overgrowth of bacteria in the tank which would use up Oxygen needed by the fish.
You can tell if the fish need more Oxygen by their gulping water at the surface of the tank in order to force Oxygen into the water. This exertion slows production of the fish and should be avoided. Nutrients that remain in the water when it leaves the growing bed are available in the adjacent pool for production of algae which then flows into the tank to feed the fish. Since these nutrients are used by the algae, the water is further purified in the pool before it returns to the fish. The algae is supplemented by chopped up edible leaves which are small enough for the fish to eat.

When water is poured into the growing bed it is poured over a pot or bowl of gravel, a grid of sticks or some other device meant to break up the water to aerate it. There needs to be another one of these devices under the outflow from the growing bed and another under the outflow of the algae pool going into the fish tank.
In addition to this aeration, someone needs to spend about 10 minutes, two or three times a day dipping water from the tank and pouring it back into the tank with a gourd or bowl for further aeration.

Construction

The first step in constructing the system is to lay out sting on the ground indicating where the components will be and outlining them for construction. The holes are then dug for the fish tank and for the algae bed with the dirt being used to construct the growing bed.


The tank is about 1M x 1M x 1M (3'x3'x3') with the bottom sloping to a low point to collect the manure. This size tank would hold 100 fish.
About 1/2 Meter (a couple feet) away from the hole dug for the fish tank a growing bed is constructed with the dirt removed from this hole and from a shallow hole dug for an algae bed. The growing bed for 100 fish is 1.2M x 7.2M (4'x24')and is as tall as is possible given the amount of dirt removed from the two holes. It should have 20cm (8") sides built up above the surface to retain a six inch layer of pea gravel, fired bits of clay or other inert growing media. Manure collects in the growing media and is decomposed by the bacteria. The nutrients are then available to the plants and are prevented from flowing back to the fish tank where they would decompose, using up the Oxygen and killing the fish by asphyxiation.

The 60cm x60cm x 7.2M (2'x2'x24') algae pool is 60cm (2') from the growing bed and parallel to it. Exiting the growing bed, there is a pipe or roof tile leading from the end farthest from the fish tank growing bed, extending out over the algae pool. There is also one leading out from the near end of the algae pool extending out over the fish tank. There is a board placed in front of the pipe or roof tile which exits the growing bed so that water builds up in the bed and then flows out slowly or the board can be removed for faster removal of the water. This provides an ebb and flow system for irrigating the plants in the bed.

This whole system is covered by a sheet of plastic about 5M x 12M (15'x40') to prevent water from leaking out of the system.