ASHLEY WONG
[CHAPTERAQUAPONICS TITLE] INTRO: Like many cities all over America, Millvale has made producing local food one of its goals for the future, but fitting an urban farm into an existing city can be difficult simply in terms of finding enough land and water. However, an efficient food production system exists. Combining AQUACULTURE [the cultivation of animals or plants in an underwater environment] and HYDROPONICS [the cultivation of plants in a soilless environment] gives us the practice of AQUAPONICS. Fish are raised as they would be in a typical fishery, but the water in which they live is circulated through bacteria cultures that break down their solid waste. The water flows into a hydroponic system where plants use the nutrients from the fish waste. This filtered water is replaced in the fish habitat, so that the fish can have clean water and stay healthy. This echoes a SYBIOTIC ENVIRONMENT that occurs in nature, in which the fish and the plants depend on and benefit from each other.
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Moyo Waterfront restaurant features an aquaponic farm on site.
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filtered water fish feed
replacement for evaporated water
fish
nitrosomonas ammonium
A CLOSED LOOP SYSTEM: Aquaculture is the practice of raising fish in tanks. Fish produce waste that, along with any uneaten fish food, accumulates in the rearing tanks. This waste contains ammonium, which is toxic to fish and cannot remain for long in the tanks. In an aquaponic system, that waste is removed and piped into a device known as a clarifier or a settler. The solid wastes break down inside the settler before flowing into the biofilter, which contains bacteria known as nitrosomonas convert the ammonium into nitrites. While the nitrites are less toxic to fish than ammonium, they are still detrimental to the fishes’ health. Different bacteria known as nitrospira convert those nitrites into nitrates, which are even less harmful to fish. Nitrate rich water is pumped out of the biofilter and runs through the hydroponic system. Plants require nitrates to grow, and they remove the nitrates from the water. The filtered water is put back into the rearing tanks for the fish. In this closed loop system, the only inputs that need to be replaced are fish food, water, and electricity. Evaporation and runoff eventually deplete the water supply, so additional water is needed to maintain the correct levels. The aquaponic system requires electricity for lighting the plants and for pumping the water.
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hydroponic plantings electricity nitrobacter nitrates nitrites lighting
THE SCALE: The size of an aquaponic system can depend on many different factors, including species of fish, variety of plants, and type of system. Aquaponic systems can be as small as an aquarium of goldfish that circulates water to a tray of oregano plants before pumping the clarified water back to the fish, a common sight in a classroom, if not a viable method of food production. On the other side of the spectrum, commercial aquaponic farms can be several acres big and may be very successful if they can find a market for its production. Somewhere in between is probably what would be most appropriate for incorporating aquaponic agriculture into Millvale. A compromise between the size of a home greenhouse, where a couple storage tubs of fish can support plants covering a backyard garden, and a small commercial operation is likely to be a good solution for Millvale.
A miniature aquaponic garden in a cafe
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SPACE TO OUTPUT RATIO: Aquaponics may not necessarily seem like an economical scheme compared to traditional farming at first glance. While soil and sunshine are free, electricity, fish feed, and occasional water supplements like iron and magnesium are not. However, aquaponic
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systems are much more efficient than traditional farming, using up to 98% less water. It also produces a large amount of fish per amount of water because the water is so much easier to maintain when filtered through the plants. Similarly, the plants do not need extra fertilizer when absorbing fish waste.
A good rule of thumb for designating the amount of space needed for each component in an aquaponics system is: a pound of fish requires two gallons of water which in turn provides enough nutrients to sustain about a square foot of hydroponic planting.
“While aquaponics is generating more and more interests, there are definite limits to be considered in the planting methods, the design elements, construction choices along with regional requirements. ...[This] make the argument for a sustainable family farm lifestyle rather than large commercial farming.� Rakocy, J., Masser M., & Losordo, T. (2006). Recirculating aquaculture tank production systems: Aquaponics integrating fish and plant culture (SRAC Publication No. 454).
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Types of fish most commonly stocked in aquaponic tanks
Several species of fish are hardy and grow quickly enough to work well in an aquaponic system. While common goldfish are not appropriate for food, they can be sold for aquariums at pet shops. They can also be used in a small aquaponics system as hardy, ornamental fish that are easy to take care of in a classroom-type setting. Barramundi, jade perch, and silver perch are popular fish for consumption around the world, but are less familiar to the North American palette. They are slightly less hardy than other options, but there is a lot of literature available that teaches neophytes to raise them effectively in an aquaponic system.
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Tilapia and catfish are the most popular fish for aquaponic systems built with the goal of commercial profit. They tolerate inconsistent water conditions, can eat aquatic weeds or commercially produced pellets, and can pack densely in aquaponic rearing tanks. They are both highly desirable menu items, and, while they are slightly more difficult to care for than goldfish, they are probably the best choice for an aquaponics farm that is meant to provide for a restaurant.
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Rearing tanks that allow observation of fish behavior
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DEEP WATER RAFT AQUAPONICS: This system involves floating the plants in the hydroponic system on rafts, typically made of polymeric foam like styrofoam. Individual plants are kept in netted pots filled with fibers from the husk of coconuts. Plants can stay in the same pots after initial transfer of seedlings into the hydroponic system, or they can be moved to other rafts as they grow to spread them out. Roots are completely submersed in the water that comes from the biofilter to absorb as much of the nutrients as possible.
SOLID MEDIUM AQUAPONICS: This system is also known as recirculating aquaponics or closed loop aquaponics. Though a hydroponic system is soilless, this system still plants the vegetables in a substrate like gravel, perlite, or expanded clay. Water either floods the beds constantly or drains and refills on a daily or hourly cycle. By periodically draining the growbeds, the roots of the plantings will have an opportunity to be exposed to air and there will not be a need to oxygenate the water that feeds the growbeds.
NUTRIENT FILM TECHNIQUE (NFT): Though this system is common in hydroponic systems, it is not as well known in aquaponics. In this system, plants in netted pots or plastic cups are placed in shallow channels. The water from the biofilter runs along the bottom of the channel in a thin film, where the plants can absorb all the nutrients they need. The bare roots of the plants make a dense mat that, while moist, are mostly exposed to the air. This way the roots can have access to water, nutrients, and oxygen.
An example of a plant growing in the shallow channels of a nutrient film technique sustem
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HIGH OUTPUT FLUORESCENT GROW LIGHTS: This is typically the most inexpensive method of lighting. Fluorescent lights are relatively cheap and produce very little heat. Thus, they can be placed very close to the plants, ensuring that they absorb as much energy as possible. Placing the lights near the plants may reduce the height required by a unit of the hydroponic system and allow the possibility to stack them vertically.
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LED LIGHTS: While these lights are more expensive than fluorescents up front, they require less electricity to produce the same light output. Over time, the electricity saved using LEDs pay back their original cost. They, too, give off very little heat. LEDs have the additional benefit of adjusting which light spectrum is used for what kind of plant. While red lights are good for budding plants, blue light is best for vegetative growth.
METAL HALIDE LIGHTS: This system gives off intensely bright light high in the blue spectrum. Again, the blue spectrum light is good for green, leafy vegetative growth. They can be up to three times brighter than typical fluorescent lights, but are much hotter, and must therefore be placed further away from the plants. The intensity of these lights mean they are not appropriate for using with seedlings.
Different lighting types need different sizes of space and requirements of energy. Lighting and HVAC energy needs are usually the highest costs of an aquaponic system, so one should consider the use of sunshine to counter the need for artificial lighting and heating. MILLVALE PIVOT STUDIO FALL 2013 Carnegie Mellon University | Mondor & King
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Moyo Waterfront market, restaurant, and urban farm in Cape Town, South Africa
The following is an excerpt from the Global Aquaponics’ blog entry “Fish-Powered Agriculture: Present Condition Of Small Scale Commercial Aquaponics” on March 8, 2012: Attaining the financial rewards in the market require entirely different skill sets than the production. Knowing your market and successfully placing products creates very little room for error, which points to a family run operation as the safest option in the current economic atmosphere. Working from home and having 24 hour control is a true benefit, making this a lifestyle. Larger size Farms pose multi-level management positions which has the potential to encumber the outcome of a commercial aquaponics venture. The skills required to run a large-scale operation
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are significant and attract big salaries which can swallow the profit margins. The smaller farms are sustainable, cleaner, less likely to fail, and are not a strain on an emerging industry. Still, the super high returns from aquaponics send off bells and whistles for producers alike making it very attractive for big players to emerge.
FARM: shop exhibition in Hackney, London
The best option for an introduction to aquaponics for Millvale would be a small, family-run system that members of the cohousing could assist with maintaining.
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Image and Information Sources
Page One Tsai, Yu. “tsai design studio: moyo waterfront restaurant + urban farm.” designboom. 6 October 2013. Web. 10 October 2013. <http://www.designboom.com/ architecture/tsai-design-studio-moyo->. Page Three Lee, Kevin. “Kijani Grows Will Bring Small, Internet Connected Aquaponics Gardens to Schools.” inhabitat. 20 August 2013. Web. 10 October 2013. <http:// inhabitat.com/kijani-grows-will-bring-small-internet-connected-aquaponicsgardens-to-schools/>. Page Five Dirksen, Kirsten. “Backyard aquaponics: DIY system to farm fish with vegetables.” YouTube. 22 August 2011. Web. 7 October 2013. Page Six “Aquaponics fish Species.” Aquaponic Fish. 2000. Web. 9 October 2013. < http:// aquaponicsfish.landscapeideasandpicture.com/aquaponic-fish-species/>. Page Seven Aquavistainc. July 2013. Web. 10 October 2013. < http://aquavistainc.tumblr. com/>. Page Eight Somma, Ryan. “Aquaponics.” Wikipedia. 1 January 1980. Web. 7 October 2013. < http://en.wikipedia.org/wiki/File:Aquaponics_with_Vibrantly_Colored_Plants. jpg>. Page Nine Left: “Grow Beds.” Food Forever Farms. aquaponicsworld. 11 October 2013. Web. 11 October 2013. <http://aquaponicsworld.net/Aquaponics_World_Aquaponics_Grow_Beds.html>.
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Center: “Type of Systems.” Backyard Aquaponics. 7 November 2004. Web. 10 October 2013. < http://www.backyardaquaponics.com/guide-to-aquaponics/ running-of-the-system/> Right: Somma, Ryan. “NFT Hydroponics: Nutrient Film Technique.” Container Gardening For You. Wikipedia. 1 January 1980. Web. 7 October 2013. < http:// www.container-gardening-for-you.com/nft-hydroponics.html>. Page Ten Right: Goldstein, Harry. “The Indoor Aquaponics Farm: Urban Organics plans to grow fish, greens, and maybe the whole indoor aquaponics industry.” IEEE Spectrum. 3 June 2013. Web. 7 October 2013. < http://spectrum.ieee.org/ green-tech/buildings/the-indoor-aquaponics-farm>. Center: “Aquaponics blog.” Blogspot. 23 September 2013. Web. 10 October 2013. < http://mpiaquaponics1.blogspot.com/2010/09/aquaponics-blog-22nd-september-2010.html>. Left: “Aquaponics.” Purdue University. YouTube. 27 October 2011. Web. 9 October 2013. Page Eleven Ahern, Stephen. “Aquaponic Windowfarm...” our.Windowfarms. 14 August 2012. Web. 7 October 2013. < http://our.windowfarms.org/2012/08/14/aquaponicwindowfarm/>. Page Twelve Tsai, Yu. “tsai design studio: moyo waterfront restaurant + urban farm.” designboom. 6 October 2013. Web. 10 October 2013. <http://www.designboom.com/ architecture/tsai-design-studio-moyo->. Page Thirteen Cafferty, Colin. “Sustainability in Inner City London.” Sustainable Cities Collective. 14 February 2013. Web. 10 October 2013.
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