Our Goal: To understand the workings of an aquaponics system and how it could possibly serve as a tool to sucess to a demographic in need.
What is Aquaponics?
Source: The Aquaponic Source
A system of agriculture that uses both, aquaculture (raising fish) and
hydroponics (soil-less growing plants).
Waste from farmed fish is converted to supply nutrients for plants to grow.
Meanwhile, the plants shade the pond to keep it cool and filter the water for the fish, and in turn the pond waters the plants.
“Zion” ~ PolyPonics at Cal Poly
What works best with aquaponics?
Leafy crops: such as herbs, lettuce, kale, Swiss Chard, etc. grow the best in an Aquaponics environment.
Plants: such as squash, cucumbers, broccoli, cabbage, and cauliflowers require a very well established aquaponic system because they have higher nutritional demands.
Fish: use either tilapia, bluegill, or koi because those have been proven to be the most successful in other aquaponic systems.
Note: The more fish used in the system, the more luck with growing fruit plants such as peppers or tomatoes.
Components of an aquaponics system
Rearing Tank: A tank or container that houses fish and aquatic animals.
Settling basin: A unit that can capture uneaten food and detached biofilm. As well as being a place where fine particles can settle out.
Biofilter: A location where bacteria can grow and convert organic wastes to carbon dioxide and ammonia to nitrates, which are used for plant nutrients.
Hydroponics: The place where plants are grown, taking excess nutrients from the water.
Sump: The lowest point in the system. It is here where the water gets pumped back into the rearing tanks.
Energy requirements for anaquaponics system
In all aquaponics system the plants and bacteria are able to filter out the fish waste but an external energy source is needed for an electronic filter and pump to keep the water circulating.
These energy requirements have been modified and are relatively small. They can be met through solar power or other alternative energy sources.
Costs of anaquaponics system
Source: FAO~$3,500 for initial set-up of greenhouse and 240 square foot system that holds 1,700 plants
- Aquaponics uses only a fraction of the water used in conventional farming.
- Aquaponics has less of an environmental impact (from less consumption of water).
- Aquaponics can grow more produce compared to produce grown conventionally in the ground.
- Aquaponics energy usage is from 70% to 92% less than a conventional or organic farm.
More Pros from Aquaponics
- Vegetables grow faster and with 3 to 4 times more density!
- An aquaponics farm does not require any soil, weeds, soil pests or pathogens.
- Less labor (e.g. no more need for fertilizer spreading, compost shredding etc).
- Only relies on electrical energy so it can be powered by solar, wind, and hydroelectric.
- Ergonomically better because seeding, planting and most harvesting can be done standing and working at waist level.
The Cons of aquaponics
Source: Aquaponic Experts
- Dealing with the fish can be difficult for some people(for some people? please elaborate)
. Water tanks sometimes need to be heated or cooled in order to keep your fish comfortable and alive.
- The initial setup costs can sometimes deter people from aquaponics. You have to invest in a tank, a filtration system, a pump, and the grow beds.
- Technical expertise is required. You’ll need to know how to run the water pump, balance out the pH level in the water, plant the correct seedlings for the system, etc.
- Higher chance of failure. Should the pump or the filtration system fail, there is a very real chance that your fish and your plants can die. They require the steady supply of clean water. Ultimately, a broken-down pump or water filter can cost you. (The answer is redundancy. One must make damn sure that the water stays aerated, and the water gets filtered).
Who can benefit from aquaponics?
- Local communities that want to purchase premium crops from local independent farms.
- Prisons that want to lower theirs costs by having inmates grow their own food through aquaponic farms.
- Countries in development that have struggled growing their own food due to lack of resources (e.g. fertile soil and water).
- Commercial businesses that want to save costs and shift to sustainable practices.
- We are currently exploring the option of implementing an aquaponics system in Rwanda.
Our initial area of interest:
Source: Comprehensive Food Security and Vulnerability Analysis
- The population is growing at high rates.
- Despite economic growth since 1994, but food security is a reoccurring issue. With half of households having difficulties accessing food.
- The large population growth has lead to deforestation, soil erosion, and decreased agricultural productivity.
- At least 2.2 million (22%) people are facing food insecurity, with 50% of the children being malnourished.
- This means that the conventional way of producing food may not be sufficient in sustaining the population expansion.
Interview with Dylan Robertson
What did he do?
Robertson was approached by Journeyman International to help develop and implement an aquaponics system in Rwanda. He traveled to Rwanda to help a small village design and set up an aquaponics system that could be utilized by the whole village.
At this point in time, Rwanda and other East African countries may not be the best place to implement an aquaponics system.
This is because:
- Lack of support domestically and internationally
- Material sourcing is very difficult
- Cultural understanding of aquaponic systems
- Rwanda established governmental countrywide support system.
What’s next for Aquaponics in Rwanda?
that if someone wishes to further implement and aquaponics system in Rwanda they should follow a three year plan. One year should be spent domestically in the United States securing funding and drawing out plans. Then two years should be spent working in the country and directly with the people that will be most affected by the aquaponics system.
Where else can aquaponics work?
“Denver jail sustainably grows food through aquaponics.”
Source: The Denver Post
- A small scale, $4,000 aquaponics system
- Trained officers and (eventually) inmates to operate
- Goal to help inmates gain skills that can be useful upon re entry into society
- Planted, raised, and harvested a multitude of vegetables. Promotes sustainable food growth.
- Saved the prison 70-90% of water that would have normally be used in a conventional garden.
Source: Inmate Mental Health
Government: They have a lot of power in allocating funding for prison programs. However, their current interest in the issue may not be very high at this point in time.
Tax Payers: Tax payers have a potentially big influence in helping get the government to fund inmate programs. They can help vote in elected officials that have power to influence institutional funding.
Prison Staff: Prison staff have a big interest in implementing an aquaponics system. The system in Denver currently provides food to feed the staff (guards) at the prison. The staff would also be the ones that are interacting with the inmates and the aquaponics system.
Inmates: Inmates probably have the larges interest in this project, however the least amount of power. They may be able to gain more power if an aquaponics program becomes more popular and is proven to be successful.
FAO Methodological Approach for Aquaponics:
Source: FAO Gaza strip
Identify communities that would benefit most from aquaponic systems based on needs assessment.
Provide education and training programs to develop farmers’ technical capacity.
Introduce and support aquaponic systems to households and establish demonstration units.
Introduce an aquaponic system, using simple and locally available materials including plastic containers, gravel, pumps and plumbing; and only establish aquaponics where there is consistent electricity and access to plant seed and fish seed.
Lessons the FAO learned from Gaza
Many of the poor households that FAO targeted first, lacked the resources to continue buying inputs and farming experience to produce quality crops.
When independently running, they did not have access to local technical support.
So first work with families that have the farming experience to ensure that the aquaponics enterprise is profitable and sustainable within the local context.
Once these households have built their capacities and have developed successful working models, future projects can include other interested families who can rely on technical support from an existing local network.
Aquaponics has to be backed with more research & volunteer efforts, and Cal Poly needs to be a part of it!
PolyPonics has already set up a small scale Aquaponics green-house, it can be studied, improved and funded more by Cal Poly.
“I took two professors on a tour of our facility, and they told me to publish joint papers with the engineering, ag and horticulture departments. If we did that, once we got renowned for it, Cal Poly would support us.“ – Dylan Robertson
Christian Barreto – Third year Liberal Arts and Engineering Studies (IE and GRC).
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Madumita Natarajan – Third year Agricultural and Environmental Plant Sciences
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Robert Gray – Third year Graphic Communications
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Elizabeth Russell – Fourth year Dairy Science (Sustainable Agriculture)
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Elise Barsch – Third year Journalism
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Sources (Many linked in text):