Small Articles and Information - Aquaponics

Alternative Ag Ventures - Aquaponics

Aquaponics is defined as the symbiotic cultivation of plants and aquatic animals in a recirculating environment. Fish waste accumulates in water as a by-product of keeping them in a closed system or tank. The water becomes high in plant nutrients and plants are grown in a way that enables them to utilize the nutrient-rich water. The plants uptake the nutrients, reducing or eliminating the water’s toxicity for the aquatic animal.

- Taken from Wikipedia, The Free Encyclopedia; www.en.wikipedia.

org, search Aquaponics

Markets for the plant products could include a variety of outlets such as direct on farm or farmers markets, local restaurants, local retailers, natural or organic food stores.

Hydroponic produce growers are located worldwide. Of over 50,000 acres in hydroponic production around the world, approximately 1,200 of those are US acres. Most of these facilities in the US are small family-owned businesses that produce on 1/8 - 1 acre. These farms produce high-quality produce and sell it locally. Smaller operations have an advantage of offering locally-grown produce with minimal transportation cost and damage. It is possible for a hydroponic grower to yield an excellent profit in this niche marketplace, offering premium local produce on less than an acre of land. Smaller growers can establish themselves near the marketplace, eliminating the problems and costs of long-distance transportation.

In addition to the smaller growers in the US, there are several large hydroponic facilities that cover as many as 60 or more acres and produce large quantities of hydroponic tomatoes, peppers, cucumbers and lettuce. (Aquaponics.com)

IntroductionAquaponics is basically a combination of hydroponics and aquaculture. With aquaponics, you are growing fish and plants (usually vegetables and herbs) in an integrated recirculating system, together. The waste from the fish provides nutrients to feed the growing plants, while the plants act as a natural water filter for the water that the fish live in. This results in a sustainable ecosystem that allows both plants and fish to thrive.

Hydroponics involves growing plants without soil. Water and nutrients create a solution that is fed directly to the plants’ roots. Most hydroponic systems involve a growing medium where the plant roots are kept moist and help support the plant. In hydroponics the plant is provided optimum growth conditions with ideal water and nutrient ratios for growth.

In aquaculture, fish are grown in enclosed tanks or ponds that can quickly become rich in nutrients due to fish waste from digestion. If in enclosed tanks, the waste water is filtered to keep the tank water free of toxic buildups.

In aquaponics, the fish waste provides a food source for the growing plants and the plants provide a natural filter for the fish. This creates

a mini ecosystem where both plants and fish can thrive. Aquaponics is the ideal answer to a fish farmers problem of disposing of nutrient rich water and a hydroponic growers need for nutrient rich water.

Market InformationWhen considering the market for the products from an aquaponics operation there are two separate categories; fish and plants, most likely leafy vegetables and/or herbs since these are best suited for aquaponics.

For the fish in an aquaponic operation there are two basic market segments, depending on which species are incorporated; the first is food. Edible fish species that do well in aquaponic operations include crappie, blue gill, tilapia, trout, perch, Arctic char, and bass. However, tilapia is the primary species used for recirculating aquaponic systems in North America due to its hardiness and ability to tolerate a wide variety of conditions.

The second outlet for aquaponic fish could be the ornamental market. Ornamental markets include tropical and cool water fish for aquarium and landscape ponds. A majority of the Midwest ornamentals include sales of goldfish, and Koi Carp.

Photo by: The Center for Innovative Food Technology on location at Rainfresh Harvests (www.rainfreshharvests.com)

Production Considerations Hydroponics:It is important, when looking into an aquaponic system, that you become educated and familiar with hydroponic growing practices and systems. There are two basic systems in use for hydroponic produce today; liquid hydroponic systems, and aggregate systems. Liquid systems have no other supporting mediums for plant roots, while aggregate uses a solid medium of some kind for root support (sand, gravel, perlite, etc.) These systems are further categorized as being either open or closed. Open meaning that once the nutrient solution is delivered to the plants it is not reused, and closed being the practice of recovering, replenishing, and recycling the solution.

Nutrients in Fish Waste:Because nutrients to the plants in an aquaponic system are delivered via fish waste, growers do not have as much control over the precise mineral element quantities as in a normal hydroponic operation. However fish waste does contain sufficient amounts of ammonia, nitrate, nitrite, phosphorus, potassium, and other micronutrients necessary for hydroponic plants. Some plant species are better adapted to this practice than others so it is important to choose wisely.

Plants Best Suited for Aquaponics:Plant selection is directly related to the amount or density of fish utilized in an aquaponic system.

The denser the fish, the more waste, which equals higher concentrations of nutrients to grow crops. Greens such as spinach, lettuces, herbs, chives, and watercress have low to medium nutritional requirements and are well adapted to growing in aquaponic systems.

Plants that yield fruit, such as tomatoes, or cucumbers have more nutritional requirements to produce the fruiting bodies on the plant and perform better in a heavily stocked (fish) system. Also, greenhouse varieties are better suited to high humidity and low light conditions compared to field varieties.

Fish Species:As mentioned above the most common species in an aquaponic system include crappie, blue gill, tilapia, trout, perch, Arctic char, and bass in the food grade category and ornamentals like goldfish, and Koi Carp.

Water Quality:Recirculating water systems used for aquaculture and or aquaponics must be managed properly to insure good quality water conditions. While the aquaponic system is relatively self sufficient for filters and nutrients, it is still important to test the water via water quality testing kits. Kits are available from aquaculture supply companies. Special attention must be given to dissolved oxygen, carbon dioxide, ammonia, nitrates, nitrites, pH, and chlorine levels to ensure a proper balance. The density of the fish, rate they are feeding, and environmental changes or fluctuations can effect

EconomicsAquaponics, like any business venture takes a significant amount of investment in equipment, the right system design, management and marketing skills.

Nelson and Pade, Inc. offers aquaponic (organic hydroponic) systems for all applications including: hobby, home food production, education, commercial and research. CropKing, Inc. also sells a hobby, educational, or home production system as well. These systems range in cost from $2,300 to over $45,000 without the greenhouse structures. With greenhouse structures you are looking at $6,300 to nearly $79,000.

The Nelson and Pade systems report having generated anywhere from 864-57,600 heads of lettuce from a single system per year depending on the size.

Current market prices in March 2008 when this report was written indicated hydroponic lettuce prices at $1.25-1.38 per head. Thus resulting in gross annual sales at $1,080 to $72,000.

Other commodities typically grown in hydroponic or aquaponic systems reported the following market trends:Tomatoes - $1.06-1.10/lb.Peppers - $1.09-1.64/lb.Cucumbers - $1.20/lb. Seedless - $7-8.50/12ct.Eggplant (med.)- $2.36/lb. (lge.) - $1.27/lb.

References and More Information References for this paper:

Aquaponics.comwww.aquaponics.comUSDA Ag Marketing Servicewww.ams.usda.gov/fv/mncs/termveg.htm Hydroponics Merle H. Jensen, Department of Plant Sciences, University of Arizonahttp://ag.arizona.edu/PLS/faculty/MERLE.htmlNational Sustainable Agriculture Informa-tion Servicewww.attra.org/attra-pub/PDF/aquaponic.pdfWikipedia, The Free Encyclopedia

http://en.wikipedia.org/wiki/aquaponicsCropKing Inc.www.cropking.com

Other references:Ohio Aquaculture Associationhttp://southcenters.osu.edu/oaa/S&S Aqua Farmwww.townsqr.com/snsaqua/index.htmlUniversity of Virgin Islands Agriculture

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Experiment Stationhttp://rps.uvi.edu/AES/Aquaculture/aquaponics.htmlAquaculture Internationalwww.Aquacultureinternational.orgGrow Powerwww.growingpower.orgCornell University Short Coursewww.aben.cornell.edu/extension/aquaculture/shortcourse.htmBackyard Aquaponicswww.BackyardaquaponicsAquaponics Journalwww.Aquaponicsjournal.comAquaculture Magazinewww.aquaculturemag.comThe Growing Edge Magazinewww.growingedge.comRainfresh Harvestswww.rainfreshharvests.com

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Center for Innovative Food Technology5555 Airport Hwy. Suite 100, Toledo, OH 43615www.cift.eisc.org P: 419.534.3710F: 419.531.8412

water quality, causing things to change quickly.

Biofiltration:This is the process of incorporating intermediate filters to collect suspended solids from fish waste, thus allowing for facilitation of ammonia and other waste conversion to forms more available to plants. Biofiltration could be a system of cartridges or utilizing a gravel-cultured hydroponic vegetable bed to deliver nutrient conversions. The bed system removes dissolved solids and provides the nitrifying bacteria a habitat for nutrient conversions.

Component Ratios:It is important to maintain the proper component ratio in an aquaponic system. This is the amount of fish tank water to volume of hydroponic media. A 1:2 ratio, respectively, is most common, but tank:bed ratios as high as 1:4 are being utilized. This variation of ratio depends greatly on a number of factors including, type of hydroponic system, fish species and density, plant species, feeding rate, etc.

Number of Fish:The number of fish that you put in your tanks directly depends on the size of tank and type of filtration system. A simple aquarium based system does well with 1-inch of fish length per gallon of water and commercial operations usually stock tanks to 1/2 pound of fish per gallon, maximum.

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Issue # 48 Aquaponics Journal www.aquaponicsjournal.com 1st Quarter, 2008

Morning Star Fishermen Inc., a tiny, die‐hard, non‐profit organization is about finished converting a 40 year old abandoned clown fish hatchery into a modern day aquaponics facility and training cen‐ter. After an arduous seven year period, and thou‐sands of hours of dedicated volunteer labor, MSF founder Hans Geissler’s dream of an aquaponic greenhouse that would serve as a research and training center is finally becoming a reality. The transformation of the old 200 feet long by 60 feet wide building has been truly remarkable. More amazing still is how suitable the original de‐sign is for an aquaponics operation considering no‐body had even heard the term ‘aquaponics’ when it was built back in the 70’s as a saltwater aquar‐ium fish hatchery. “You have to give Hans a lot of credit; first for hav‐ing the vision and the tenacity to invest in a con‐demned facility that laid in ruin, and then for hav‐ing the ingenuity and the determination to realize a transformation like this.” said Javier Colley, Morning Star Fishermen’s new volunteer Executive Director.

With a mission to help in the fight against world hunger, since the early 90’s, Morning Star Fisher‐men has been proposing aquaponics as a feasible and reliable means of producing much needed pro‐tein for impoverished communities in countries devastated by hunger and starvation. We all know the numbers; only one‐third of the world is well‐fed, while the rest is under‐nourished or starving to death. Since you started reading this article, at least 500 people have died of starvation all over the world. If you ever wondered what could be done about it, teaching aquaponics is something that can result in a permanent ongoing supply of nutritious food grown by and for each specific community. MSF’s

Hans and Sigrid Geissler, Founders, Morning Start Fishermen

Morning Star Fishermen, Inc. Morning Star Fishermen, Inc. Helps to Fight HungerHelps to Fight Hunger with Aquaponics with Aquaponics

By Javier Colley

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motto is; ‘Give a man a fish, he eats for one day…teach a man to grow fish and vegetables, and the whole commu‐nity eats’. At Morning Star Fishermen we believe that solutions to hunger and poverty can be found at the grassroots level. Teaching people to grow their own food; assisting small farmers to implement simple and effective technology, and providing the education and training necessary for replica‐tion, maintenance and sustainability can be a long‐term solution to hunger and poverty. The key to the success of our humanitarian project is to learn to attain sustainability ourselves, and then train oth‐ers to become sustainable. Capacity building, education and hands‐on training are the foundation for all MSF initia‐tives. Since the year 2000, when we moved to our current head‐quarters in Dade City, Florida, we have been striving to adopt the latest aquaculture and aquaponics technologies, which can later be incorporated into our curriculum. Last summer we attended Dr. James Rakocy’s Aquaponics Short Course at the University of the Virgin Islands in St. Croix, and we are teaming with Nelson and Pade to expand our course offering to include commercial oriented modules and cover more sophisticated intensive technologies in our curriculum. In addition to the main aquaponic production area, our main building also houses a 9,000 gal. capacity hatchery and a classroom. Our main greenhouse aquaponics system has 36,000 gal. of fish grow‐out capacity and 900 sq. ft. of raft hydroponics surface area. We also have a variety of smaller scale demonstration aquaponic system indoors and outdoors, and an older traditional aquaculture fish tank farm with additional 40,000 gal capacity in another part of our 10 acre property. Our main aquaponic system tries to emulate Dr. Rakocy's UVI recirculating aquaponic system as close as possible. We have proportionally 25% more fish production capacity than plant production surface area, compared to the UVI system. There is an advantage in having additional fish “space,” because you can produce the same amount of fish using lower stocking densities. This gives you a wider margin for error than trying to use higher stocking densities. The fish seem to grow faster, plus it makes it easier for inexperienced and uneducated growers to be successful.

Morning Star Fishermen Training Center Photos: Top: the classroom; middle: the wet lab; bottom: some of the fish tanks; Left page, top: the raft tanks in the green‐

house with basil growing

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We are growing two different Tilapia hybrids, the Rocky Mountain white, and a red strain of Nile Tilapia crossed with Oreochromis mossambicus, as well as the blue Tilapia found locally in Florida, O. aureus. We have started to plant basil and other herbs, as well as a variety of vegetables, legumes and even grassy plants that can be used as forage for farm animals in arid or desert regions. Using the same criteria and production parameters that UVI uses, our greenhouse aquaponic system has the capacity to produce approximately 10,000 lb of Tilapia and an additional 10,000 lb. of vegetables and herbs per year. We specialize in offering interactive hands‐on training, which is key to the success of any aquaponic enterprise, whether it is for community development purposes, or commercial interest. Peo‐ple don’t realize how valuable this is until they come to one of our courses and spend some time actually helping to run and operate a working aquaponic farm and fish hatchery. We have a variety of courses and seminars, ranging from one‐day introductory seminars to more intensive three month courses, with dormitory facilities that can house up to 12 people at a time. Still, we are a very small organization and the truth is that we need help to turn MSF into the world class organization it could become. In the fifteen years that we have been in operation, a lot of talented, qualified people have come and gone from us. The list is really impressive and we owe a lot to each of these individu‐als. Without them MSF would not be what it is today. All of them brought good things to the table, but we were not able to provide the support that they required to remain working with us. During this time, we have been able to improve our organiza‐tional structure and our financial situation is improving as well so, hopefully, we will be able to attract and retain more qualified in‐dividuals in the near future. We now have a fully operational facility, and we are starting to get a lot of attention from the academic and research community. We are strategically located in the middle of the three largest uni‐versities in Florida, all three of which are in the list of the top 10

Activities at Morning Star Fishermen: top to bottom: transplanting basil seedlings; inspecting fish health;

maintaining the aquaponic systems; harvesting tilapia.

www.aquaponics.com

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largest universities in the country, including The University of Florida (UF) at Gainesville that is the second largest university campus in the nation by enrollment, and is Florida’s top agricultural school. It is just a matter of time before we move to the next level. In the mean time, we are also building a sister aq‐uaponics and sustainable farming training facility in Nicaragua, one of the poorest countries in the Western Hemisphere. We received a grant from The Rotary Foundation, and three acres were do‐nated for this project by Silvio Echaverry, a pro‐fessor emeritus from that country’s top agricul‐tural university, Universidad Nacional Agraria (UNA) in Managua. This facility will make our ser‐vices more accessible for students and commu‐nity leaders from Latin America, who would oth‐erwise be unable to come to the United States for training. It is truly remarkable that Morning Star Fishermen has been able to get so far and do so much with

so little. We continue to struggle financially, we continue to be under manned, but we have a pas‐sion that surpasses those limitations. We are building a strong foundation, and are working to have everything we need in place in order to achieve our maximum potential. Until then, we remain a clean canvas upon which we expect even greater work to be done in the not too distant fu‐ture. About the Author: Javier Colley has been with Morning Star Fishermen since May 2007. Before coming to Morning Star Fishermen, he worked 16 years in the seafood processing industry as R&D Manager and Process Manager for Bumble Bee Seafood, Inc. He has a bachelor’s degree in biology from the University of Notre Dame, and completed four years of graduate studies at the University of Puerto Rico’s Department of Aquaculture and Ma‐rine Sciences where he also worked as a Research Assistant. Javier can be reached by email at [email protected].

Mexican Hydroponic Association Presents:

6th International Course and Congress on Hydroponics

Toluca, Mexico

April 17-19, 2008

At the 6th International Course and Congress on Hydroponics, The Mexican Hydroponics As-

sociation, with industry scientists, professors and experts presenting information, will offer

the most comprehensive program on soilless culture in the western hemisphere. Those inter-

ested in soilless culture will find the program to offer innovation, new and sustainable tech-

nology and instruction on both low tech and the most advanced hydroponic methods.

Simultaneous to the course and congress, an exhibition area will provide participants the op-

portunity to meet suppliers of equipment, seeds, fertilizers and educational materials.

Presented in English and Spanish www.hidroponia.org.mx

BIOCYCLE FEBRUARY 2009 27

ACROSS the U.S., as small, localgroceries close in the face ofcompetition from large, distantsupercenters, more and moreimpoverished inner city and ru-ral residents live in “fooddeserts,” without access to

fresh, affordable food. In 2007, USDA re-ported that 7 percent of U.S. households suf-fer from low food security while 4.1 percentof U.S. households suffer from very low foodsecurity. A project at Saginaw Valley StateUniversity (SVSU) in Saginaw, Michigan,set out to meet these challenges throughaquaponics (a combination of hydroponicsand aquaculture) and vermicomposting.

In 2003, a pair of experimental green-houses was developed at SVSU by a multi-disciplinary team of faculty, staff and stu-dents. Funded by a grant from the AllenFoundation, a Midland, Michigan-basedgroup, the project seeks to identify a cost-ef-fective, year-round means to produce fruitsand vegetables locally and organically. TheSVSU system incorporates three basic fea-tures: An economically designed aquaponicssystem to efficiently grow fruits and vegeta-bles with minimal horizontal space, fertiliz-er and water; Vermiculture to efficientlyconvert campus food waste and paper wasteinto organic fertilizer for use in the system;

and, Renewable energy, such as passive so-lar heat, to cut the costs of operating boththe vermiculture and hydroponic units.

Four criteria drove the project: Cost ofcomponents and operations must not ex-ceed what the global market can currentlybear; Scale of the project must be local, withdimensions such that losses do not exceedgains; Resource availability, with local con-struction materials and alternative energysources used whenever possible; and Easeof Implementation, with installation andoperation managed by the local labor force.

The aim was to develop a system thatcould be widely replicated in economicallyblighted regions, used as a cost-effective ve-hicle to teach the public the importance ofgrowing the right fruits and vegetables toensure a healthy diet. The grand vision wasto ultimately establish regional productionsystems in population centers worldwide.

STARTING WITH HYDROPONICSHydroponics is gaining widespread at-

tention because it can outperform soil-based cropping, due to more efficient up-take of nutrients, with faster plant growthand higher yields per square foot of hori-zontal area. In the first production year atSVSU, three hundred pounds of tomatoeswere produced on a tiered hydroponic unit.

Project atSaginaw ValleyState Universityin Michiganexperiments withaquaponics andvermicompostingto increase foodsecurity.

Beth Jorgensen, EdwardMeisel, Chris Schilling,

David Swenson andBrian Thomas

FISH AND WORMS

DEVELOPINGFOOD PRODUCTIONSYSTEMS INPOPULATION CENTERS

Greenhouses integratehydroponics andvermiculture for year-round fruit and vegetableproduction, such as tomatoplants (left).

The high cost for turnkey hy-droponic systems can be pro-hibitive, so the SVSU teamused a relatively primitive, do-it-yourself system, with cheapand readily available materialsfrom the local hardware store:two-by-four lumber, plastic wa-ter pipe and an ordinary foun-tain pump. A provisionalpatent application has beenfiled on this system.

Other cost-intensive aspects of hydropon-ics are electricity to operate pumps and ar-tificial lighting, and heat for year-roundgrowing. Although alternative energysources like wind turbines, solar panels,geothermal heat pumps and biomass fur-naces have high capital costs, once opera-tional these investments provide cheap,clean energy.

One low-cost energy solution used atSVSU is passive solar heating of the bench-es that support potted plants. Benches wereconstructed from recycled pickle barrelsfilled with water and topped with durable,recycled fencing material. The water bar-rels provide a significant thermal bufferingcapacity that allows solar heat, absorbedduring the day, to be released at night.

INTRODUCING FISH AND WORMSSpecialty chemicals that serve as plant

nutrients and herbicides pose anothercostly problem with hydroponics, as theyare usually produced from nonsustainablepetroleum or natural gas. At SVSU, a com-bination of vermicompost tea and the de-velopment of aquaponics have replacedthese chemicals.

Aquaponics is essentially the same as hy-droponics, except that plant nutrients areprovided by fish excrement instead of syn-thetic chemicals. Also, plants filter the wa-ter before it returns to the fish tanks. Usingsimple plumbing and hardware, water in afish tank is circulated through a hydropon-ic system where naturally occurring bacte-ria produce powerful organic fertilizer. Theonly chemical input is fish food.

At SVSU, a 150-gallon water tank con-tains 12 Koi fish. A fountain aerates the wa-ter for the Koi, and a pump circulates fishtank water into two 50-gallon plastic tanksthat serve as hydroponic grow beds. Thewater in each grow bed recirculates backinto the fish tank using a so-called “ebb andflow” system, where an electric timer con-trols a pump that intermittently floods anddrains each grow bed. The grow beds arefilled with Hydroton clay aggregate, a grav-el-like material that is manufactured inhigh-tech kilns in Germany, and supportsthe roots of the growing plants. By simplycirculating fish tank water through eachgrow bed, two types of bacteria, Nitro-somonas and Nitrobacter, naturally beginto grow on aggregate surfaces. In turn,these bacteria convert ammonia, which isexcreted by the fish and dissolved in water,

to nitrate, a powerful organic fertilizer(similar to the fertilizer used in large-scaleAmerican agriculture, conventionally pro-duced from natural gas).

SVSU is now incorporating a vermiculturesystem into the university greenhouses. Af-ter attending a short course from Will Allenat Growing Power, Inc. (see “CompostingAnd Local Food Merge At Urban Garden,”Biocycle November 2008), the followingwaste recycling process was implemented,with cooperation from Aramark Corpora-tion, the manager of SVSU Dining Services.

Cooks in the university kitchen placefruit and vegetable scraps into five-gallonplastic buckets. A Starbucks café located oncampus provides spent coffee grounds. Onany given school day, 10 to 15 buckets ofcombined food scraps and coffee groundsare hauled to the university greenhouses.The weight and contents of each bucket arerecorded to monitor consumption rate. Dur-ing the fall 2008 semester, 15,175 pounds ofcombined food scraps and coffee groundswere collected.

At the greenhouse, red wiggler wormsare cultivated in a series of eight vermicul-ture beds, 4 feet wide by 8 feet long by 8inches high, built from ordinary construc-tion lumber. Worms are fed a mixture of 50percent food scraps, including coffeegrounds, and 50 percent shredded officephotocopier paper donated by Veteran’s Af-fairs Medical Center of Saginaw, Michigan.

Vermicompost is slowly generated andperiodically separated from the worm binusing a simple sieve consisting of a galva-nized wire screen (1/4 to 3/8-inch squaremesh). The screen is laid on top of a wormbin, and raw material (worms plus com-post) is gently spread onto the screen’s sur-face. Fleeing from the overhead light, theworms quickly migrate through the screen,falling below into the bed.

Each bed is monitored by an inexpensivehandheld probe that simultaneously mea-sures soil moisture and pH. Moisture con-centration must be maintained between 50and 60 percent, while pH must be main-

28 BIOCYCLE FEBRUARY 2009

Leachate is collected from thevermicompost bins, andaerated to produce composttea.

The school’s aquaponics systemhas a 150-gallon tank with 12Koi fish.

tained between 6 and 8. By carefully controlling what theworms eat, pH can be maintained without addition of chem-icals. To aerate the mixture, the solid material in each wormbed is occasionally turned by pitchfork, as needed.

To maintain the correct moisture concentration, watermist is briefly sprayed on the surface of each worm bed dai-ly, using a garden sprayer controlled by an electronictimer. Excess water leaches through the vermicompost anddrains through a series of 1/2-inch diameter holes drilledinto the plywood bottom of each worm bed. The aqueousleachate drips into a series of gutters fabricated from re-cycled plastic drain pipe, and is collected in a series of 5-gallon plastic buckets.

Leachate collected in each bucket is periodically pouredinto 55-gallon recycled plastic barrels. These barrels are aer-ated with a simple fish tank aerator, which reduces odor andalso keeps bacteria active, turning the leachate into a valu-able vermicompost tea. The tea is then used in the universi-ty greenhouse to fertilize plants grown hydroponically or intopsoil, providing an economic alternative to commercial nu-trient solutions. The solid compost that remains is used as asoil amendment in potted plants in the greenhouse.

COMMUNITY OUTREACHIn 2007, the Green Cardinal Initiative (GCI) was formed,

a consortium of students, faculty and staff interested indefining SVSU’s role in the green movement, both withinand outside the university. Initiated by sociologist BrianThomas, GCI originated around activities in the greenhouseincluding developing methods for local food production anddistribution in urban settings, engaging student artists inpublicizing GCI and food production activities, and develop-ing affordable energy and fertilizer options for both urbanand rural settings in the U.S.

The Greenhouse Project and GCI have coordinated withthree local nonprofits located in an economically depressedpart of Saginaw — Houghton Jones Neighborhood Center,

the Good Neighbors Mission and the Mustard Seed — to de-velop the Saginaw Urban Food Initiative. The aim is to in-crease the availability of fresh produce to the communitythrough the development of urban agriculture. Funding wasobtained from the Saginaw Community Foundation to installhydroponics units in the Houghton-Jones NeighborhoodCenter and the Good Neighbors Mission to explore the po-tential of year-round food production. The project’s goal is totake systems that have been tested at SVSU and examinetheir effectiveness in real-world circumstances.

With technical support and training by SVSU faculty andstaff, members of these two organizations recently began op-erating hydroponics systems, monitoring productivity and la-bor and energy requirements. Similar to the setup at SVSU,vermiculture systems have been established at each site tosupplement the hydroponics systems. Staff members at eachsite bring food waste and scrap paper from home to feed theworms.

Using experimental data from the university greenhous-es, a financial model is currently being built to calculate theanticipated benefits that these community centers and oth-er prospective organizations can anticipate. Input data in-cludes labor requirements, installation and operating costs,rates of worm reproduction and the rates of food waste andpaper waste delivered. Output data includes rates of wastereduction and the yields of produce, worm tea and vermi-compost.

Additional information on this and other projects un-derway at the SVSU greenhouses can be found atwww.greencardinal.org.

Beth Jorgensen, Ph.D., is an Assistant Professor of English; Ed-ward Meisel is a Chemistry Lecturer and University GreenhouseDirector; Chris Schilling, Ph.D., is the C.J. Strosacker Professorand Chair of Engineering; David Swenson, Ph.D. is the Dow Pro-fessor and Chair of Chemistry (retired); and Brian Thomas,Ph.D., is an Assistant Professor of Sociology.

BIOCYCLE FEBRUARY 2009 29

ADVANCING COMPOSTING, ORGANICS RECYCLING& RENEWABLE ENERGY

419 State Avenue, Emmaus, PA 18049-3097610-967-4135 • www.biocycle.net

Reprinted With Permission From:February, 2009

2006 Agricultural Experiment Station Research Report

It’s no surprise that fish and herbs go together on a dinner plate, but at the University of Arizona’s Environmental Research Laboratory they also grow together quite well. In a

greenhouse “aquaponics” system that combines aquaculture with hydroponics, Nile tilapia swim in 250-gallon tanks (about 950 liters) linked to hydroponic growing beds planted with Genovese basil. The system conserves water and nutrients by circulating fish waste to the plants, which in turn filter the water that goes back to the fish.

While aquaponic methods have been studied before, the goal of this project was to find a minimal ratio of fish mass to plant mass that would produce commercial grade basil. Graduate student Jon Jordan and professor Joel Cuello, both from the Department of Agricultural and Biosystems Engineering, and professor Kevin Fitzsimmons, Department of Soil, Water and Environmental Science, wanted to develop a simple system that could be replicated by small or large growers anywhere in the world. Expanding urban populations and shrinking farmland worldwide have forced growers to develop intensive agriculture systems that yield more food on less land.

In 2005 the team set up nine separate aquaponic units, stocked them with fish, planted the basil, and began testing different fish densities and feeding rates. The amount of basil planted for each unit remained the same for all treatments, but the fish tanks were stocked with 3, 6, and 9 kilograms of tilapia. The fish were fed 60, 90 and 120 grams of feed per day, respectively in the first experiment. In a second experiment 4, 6 and 8 kilos of fish were fed 60, 90 and 120 grams of feed per day.

Sustainable aquaculture and hydroponicsBy Susan McGinley

“We varied the biomass and feed rates of the fish in different replications of the trial while keeping the plant numbers the same,” Jordan says. “We wanted acceptable market quality for the fish and the basil. There was a notable difference in quality and quantity of basil between treatments. The system was also very water efficient, with a water loss of only 0.7 percent of the total system volume per day due to evaporation. Additionally, no extra fertilizers aside from fish feed were added.”

The researchers selected the Nile tilapia (Oreochromis niloticus), a native African fish, for its hardiness, preference for warm water, wide availability, and worldwide popularity as a food fish, according to Fitzsimmons.

“Tilapia is the second most common farmed fish in the world and now is the fifth most popular seafood item for US consumers,” he says. “It’s ideal for aquaponic systems because it’s hardy and disease resistant. It thrives in warm water, and large schools of fish can be reared in small volumes of water.”

Basil (Ocimum basilicum) was chosen as the complementary plant crop for its commercial value, the simplicity of its culture, and its preference for warm, high-light environments, according to the research team. The plants were germinated separately and

MarketGrade

Fishwith a

SideofBasil

The UA aquaponic system links 250-gallon tanks of tilapia (foreground) with hydroponic beds of basil (background). The system conserves water and nutrients by circulating fish waste to the plants, which in turn filter the water that goes back to the fish.

Jon

Jord

an

The system conserves water and nutrients by circulating fish waste to the plants, which in

turn filter the water that goes back to the fish.

Market Grade Fish with a Side of Basil

The University of Arizona College of Agriculture and Life Sciences2

transplanted into each of the .9 square meter hydroponic modules at the rate of 34 plants per module.

“There were six treatments, with differing amounts of fish,” Cuello says. “Pairing aquaculture with hydroponics has been done before, but mainly as demonstrations. “We’ve actually established the minimal amount of fish for our 1400-liter system. If you want to increase production, you just increase the size of the project, keeping the same ratio of fish to plants.”

“Our minimum fish stocking density and feed rate to obtain commercially acceptable basil plants was found to be six kilograms of fish receiving 60 grams of feed per day for the 34 basil plants, spread over a 0.9 square-meter growing area,” Jordan explains. He notes that he would recommend a design ratio closer to 100 grams of feed per square meter of crop growing space, but that wasn’t strictly supported by the statistics.

The yield depends entirely on the scale of the system and the way it’s managed. “In my particular case I was yielding two to three kilograms of basil per square meter per 40-day growing cycle,” Jordan says. “Fish growth was a lot more variable between experiments and I can’t really generalize about what was yielded.”

Over the past hundred years, as the world’s population has expanded exponentially, modern agriculture has developed ways to keep up with the food

demand by producing more food on less land. This major accomplishment has proved Malthus’ predictions of human demise wrong, according to Cuello. Malthus wrote that human populations increase geometrically (if unchecked), while food production can only increase arithmetically, leading eventually to mass starvation.

“Instead, agricultural science and agricultural engineering have helped realize large-scale food production and have increased the carrying capacity of the earth,” Cuello says. Yet some of these farming techniques have contributed

Nile tilapia serve as an ideal fish in an aquaponic sytem that combines aquaculture and hydroponically-grown plants. Tilapia are hardy and disease-resistant, widely available and popular worldwide as a food fish.

Jon

Jord

an

The aquaponic system yields high quality basil.

Jon

Jord

an

to air, water and soil pollution, and the depletion of fossil fuels.

“Our problem now is how do we keep up with the demand for agricultural production without depleting our natural resources and damaging our environment? Americans are currently the number one consumers in the world, consuming at least one-fourth of every natural resource while representing only 1/20th of the global population,” Cuello says. “But in the decades to come, hundreds of millions will be joining the middle class in China, India and other developing countries. Our challenge over the next hundred years is sustainability.”

The goal is to produce high quality food and make a profit while preserving the environment. By yielding market grade fish and basil, conserving water and using no pesticides or external fertilizer aside from the fish feed, the greenhouse aquaponics system tested at the UA is a step toward this goal.

“We’re using what we have, combined with new technology,” Cuello says. Ã

Contact Joel [email protected]

Kevin [email protected]

sparked university interest, but the territory had no aquaculture industry. Lacking an established industry in search of immediate answers to commercial questions, Rakocy enjoyed, “a luxury of a long, long period of time to develop these systems.” The system began as three and one-half oil barrels, two dedicated to production, on the back porch of Building E, the Agricultural Experiment Station headquarters. Yet in a little more than four months this small set up generated more than 100 pounds of food: 30 pounds of fish, 8 pounds of lettuce and 64 pounds of tomatoes. “The basic design that we hit on then is the design that we’ve followed ever since,” said Rakocy. Following this early success, the team experimented with adjustments in size and ratio of fish to plants. Early problems such as nutrient accumulation, clogging from incorrect pipe size and poor drainage were corrected during these trials. The implemen-

of UVI to learn firsthand about this long-running and remarkably efficient program.

History and System Overview

The globally recognized program began in earnest 27 years ago when Rakocy, then conducting aquaponics research with aquatic plants at Auburn University in Alabama, joined UVI charged with developing aqua-ponic systems appropriate for the U.S. Virgin Islands. Like many island paradises in the Carib-bean, St Croix has no lakes or rivers. It depen-dends on stored rainwater for its freshwater needs. The island also has limited agricul-tural land. In addition to the need to create a system viable for an area with restricted land and water, Rakocy wanted to be able to recycle nutrients, since discharge of potential pollutants is also a sensitive issue for island ecosystems. Specific needs and burgeoning research

The tiny, tranquil Caribbean island of St Croix, part of the U.S. Virgin Islands, may seem an unlikely place to find the world’s most established aquaponics program. But almost three decades of research have yielded a nearly flawless production system and a wealth of experience to share. Dr. James Rakocy, director of the University of the Virgin Islands Agricultural Experi-ment Station, believes the effectiveness of the aquaponics system illustrates the best of both hydroponics and aquaculture but is simpler to operate than either. “I like to call raft aquaponics the lazy man’s hydroponics,” said Rakocy with a laugh. Of course sloth has not been part of the research process for the UVI aquaponics team, which through trial and error devel-oped a system that conserves both water and land resources. Now the team is sharing its successes with others. Academics, entrepre-neurs and enthusiasts from across the globe are making the trek to the St Croix campus

Heads of lettuce grown in a raft hydroponic system wait for harvest at the University of the Virgin Islands on St. Croix. The lettuce is fed from water from the system’s aquaculture

tanks, which is then recirculated back to the fish.

Photos courtesy of Dr. James Rakocy, University of the Virgin Islands

Working Together

By GRETCHEN SHERRIll

24 THE GROWING EDGE March/Apr i l 200 WWW.GROWINGEDGE.COM

robust and simple to operate, especially in comparison to hydroponics and aquaculture systems.

System Advantages

Aquaponic systems retain water for long periods of time, require less monitoring, and provide free nutrients. Rakocy believes UVI’s aquaponic system encounters fewer pest and disease problems than traditional hydroponic systems due to the amount of organic material in the water. In contrast to the sought after ster-ile environment of hydroponics, the UVI aquaponics system thrives on a diversity of bacteria – bacteria that can be antagonistic to pathogens and bacteria that boost plants’ immune systems. In fact, the UVI aquaponics system has operated for several years without changing the water. “We like to go dirty,” chuckles Rakocy. Other than pH tests, the UVI aquaponic system’s water is tested only once per year when experiments are not being conducted. Water pH must be monitored daily and base added to maintain a neutral 7.0. The base added to maintain pH serves a dual purpose as a nutrient supplement.

the water, cleaning it for the fish. The water then passes back through the system to the fish. Fish produc-tion is staggered with a harvest every six weeks. The UVI system employs addi-tional tilapia fingerlings to keep the clarifier sides and drain lines clean – a job that would otherwise have to be done manually. The ratio of fish to plant pro-duction has been calculated to balance nutrient generation from fish with nutrient removal by plants. The ratio is expressed as the weight of feed given to fish on a daily basis relative to the plant growing area. The optimum ratio is 60-100 grams per square meter of plant growing area per day. By applying this ratio and attending to minor general maintenance the system can operate uninterrupted for years, another key to success. A new aquaponics system requires an establishment time of 6 weeks for essential bacteria and 18 weeks until all four fish rearing tanks are stocked. Due to the required establishment time, Rakocy warns, “Once you start it, you never want to stop the system.” Rakocy refers to the UVI aquaponic system not as high tech but as “appropriate technology.” He considers the system reliable,

tation of raft hydroponics resulted from prob-lems with gravel which accumulated solids, clogged and became a source of ammonia. In addition, gravel requires construction of heavy support structures to hold the extra weight. The raft system, comprised of float-ing sheets of polystyrene set with net pots, solved the gravel problems and combined the biofiltration and hydroponic requirements. During this research and development period, Rakocy devoted his time to field work construction, “digging holes and trenches.” Building an aquaponics system requires construction skills and the work may be off-putting to some. As Rakocy admits, the building the system is “much more advanced than installing a home aquarium or backyard garden.” Following several scale-ups and a half dozen more iterations to work out the remain-ing structural and organizational kinks, the team developed the current commercial-size system that Rakocy says leaves little room for improvement. The system they’ve hit on consists of four aquaculture tanks in which tilapia are raised. Tilapia are fast growing, can tolerate a wide variety of environmental conditions and have firm white meat. The water from the aquaculture tank then feeds through sump, clarifier and degassing tanks that remove most of the solids from the fish waste. The water is then pumped into six hydroponic tanks that are fed by effluent lines. The crops growing hydroponically take nutrients from

Dr. Rakocy with a fish from the aquaponics system he helped

design and build.

Working Together

WWW.GROWINGEDGE.COM March/Apr i l 200 THE GROWING EDGE 25

organic could be worked out,” Schultz said, “and the produce tastes so delicious and that’s a fact.” Of course not all plants grow well in the UVI aquaponics system. The raft system does not accommodate root crops, and certain crops, such as spinach, prefer a cooler, less tropical climate than that of St Croix. Even among the current crop of cantaloupe, the vine variety thrived while the bush variety did not. Research specialist Donald Bailey sees this disappointing bush crop as a valu-able lesson. “We teach with examples and with this varietal difference, we can inform farmers and save them production dollars,” explains Bailey. In fact, a goal for the research team is to increase profits for farmers. These findings will be shared as part of the UVI aquaponics short course, developed and administered by Rakocy and his staff. The short course has more than doubled in attendance and gained global attention in just a few years.

Aquaponics’ Future

New technologies take time to be accepted and implemented. However, global water shortages have created a more urgent interest in aquaponics, one of the most water-efficient systems in the world, Rakocy said. UVI’s success and lengthy track record of research has generated interest and led to the implementation of similar systems in several locations in the U.S. and abroad – including the New Jersey EcoComplex at Rutgers University and the Crop Diversifica-tion Center South in Alberta, Canada. The Canadian system has produced more than 60 types of vegetables. Raocy cites planned multimillion-dollar commercial projects in Australia and the U.S. as evidence of recent investment growth in the aquaponics industry. When thinking back to beginning of his career in the late 1970s, Rakocy said that he and other aquaponic proponents were considered “on the lunatic fringe.” With the completion of the UVI com-mercial-scale aquaponic system and the implementation of the short course, Rakocy has connected with a growing mainstream commercial and academic interest in aqua-ponics. An interest he finds as an amazing and personally gratifying acceptance of a life’s work.

The fish-rearing tanks, foreground, and their related pumps and filters are under

cover, while the lettuce growing in a raft hydroponic system stretches out beyond

them in the sunlight.

Each summer since 1999 the University of the Virgin Islands aquaponics short course draws people from all around the world to the island of St. Croix for an intensive one-week session on aquaponics. This year from June 15 through 21 aquapon-ics enthusiasts will receive hands-on training, detailed procedures manuals and advice on daily operations. The UVI team has trained 271 students from four U.S. territories, 35 states, 35 countries and all seven continents. No more than 64 students are accepted into the course each year, the number capped to allow for small groups during hands-on sessions. “They shared everything they did wrong. Instead of burying mistakes they freely shared them and probably saved me $30,000 in failed experiments,” said Tim Mann of Hawaii, who participated in 2007. Enrollment in the 2008 program is open. The course costs $920 for early registration (by May 16) and $1,020 for late registrations. Information on the course and online registration can be obtained at the program’s Web site: http://rps.uvi.edu/AES/Aquaculture/UVIShortCourse.html.

Aquaponics short course brings the world

to St. Croix

system water daily due to excess nitrate accumula-tion. UVI’s system uses nitrates and other nutrients for plant growth, so it dis-charges less than one per-cent of system water daily, alleviating the potential for pollution related to water discharge. The UVI system not only recovers nutrients lost as

waste in traditional aquaculture systems but also produces the valuable by-product of plants, which typically generate more income than the fish. In contrast to aquaculture, the plants serve as the biofilter, eliminating that maintenance expense. “Aquaponics is the only system in the world that has a biofilter that makes money,” Rakocy said. On one-eighth of an acre of land the UVI aquaponic system produces an estimated 25,000 pounds of food per year. One acre would have the potential yield of 200,000 pounds of food per year. In contrast to dirt-grown field crops, plants grown in aquaponic systems tend to grow more rapidly, have ample water and nutrients, and enjoy a weed-free environment, Rakocy said. In experiments comparing the two, the UVI aquaponics system yielded three times more basil and seventeen times more okra than field crops. However, vegetable production is never foolproof: insect damage and disease occur. Aquaponic growers can’t use the pesticides and insecticides that traditional agriculture employs. In aquaponic systems of interde-pendent fish and plants, treatment of one might harm the other. Aquaponics depends on biologic control methods and is therefore guaranteed to be pesticide free. UVI’s aquaponics team members Charlie Schultz, a research analyst, and Jason Dana-her say aquaponics might be the answer to growers seeking to market organic produce. Research specialist Danaher cites growing aquaculture industry interest in developing methods to certify products organic and sell them as such. Schultz believes aquaponics offers a solution to the need for an organic-based fertilizer for hydroponics production and an antidote to the rising expense of utilizing petroleum-based products. “Our system has the potential to be a very big leader, if interest in certifying it to be

Unlike traditional hydroponic solutions that require a complete nutrient mix, the UVI system’s tilapia provide adequate amounts of 10 of the 13 nutrients essential to plants. Only potassium, calcium and iron must be supplemented. And to maintain the proper pH level the operators add either calcium hydroxide or potassium hydroxide, which provide the missing potassium and calcium nutrients. Iron is added separately. Normal recirculating aquaculture systems discharge an estimated five to ten percent of

2 THE GROWING EDGE March/Apr i l 200 WWW.GROWINGEDGE.COM

AQUAPONICS - Combining hydroponics & aquaculture

36 Small FARMS May 2009

By Helen Smith

There are a number of rea-sons why a small farmermight want to consideraquaponics. One is shortageof space and another isshortage of water. A thirdreason could be the desire tobecome as self-sufficient aspossible while producingfresh food, and a fourthmight be a lack of time orinterest to weed, water, fer-tilise and tend a full sizedvegetable garden.It may seem odd to think

that a farmer might be shortof space, but if your propertyis, say, four hectares and youwant a reasonable orchard, agood sized shed, a smalldam, to run a few sheep orcattle and maybe a pony forthe children, it could be acrush to provide enoughland for a decent sized veg-etable patch. Added to that,small farm or not, shortageof water is a commonprob-lem for many farmers.As the name suggests,

aquaponics combines bothaquaculture and hydropon-ics, with the combinationbringing greater benefitsthan can be derived fromeach of the components op-erated separately. Put simply,the water in a fish tank ispumped through soil-lessgrowbeds before being re-turned to the tank, purifiedby bacteria in the growingmedium of the growbeds.The plants benefit from thewater made nutrient-rich bythe fish, who benefit fromthe cleaned and oxygenatedwater returned from thegrowbeds. With a basicallyclosed system, there is almostno waste and both fish andvegetables grow faster than ifthey were produced conven-tionally. Reports state that

both fish and vegetables tastebetter too.Joel Malcolm stumbledupon aquaponics in 2000while searching the internetfor different ways to growplants. Inspired by a pio-neering American couple, hebegan experimenting with asmall makeshift aquaponicssystem in his own back-yard.The possibilities soon be-came evident and he contin-ued to develop systems thatare now so successful hishobby has turned into abusiness and he has recentlyopened a display centre atJandakot near Perth - theonly aquaponics shop in theworld, Joel claims.‘There are three main ele-ments essential for success,’he says, ‘fish, plants and bac-teria. Fish expel ammoniathrough their gills, and whileplants have no use for am-monia, two types of natu-rally occurring bacteria(Nitrosomonates and Ni-trobacter) in the growingmedium break it down inthe water, first into nitritesand then into nitrates whichthe plants can use, at thesame time cleaning and aer-ating the water before it is re-turned to the fish tank.’Other nutrients essential forplant growth such as potas-sium, phosphorous andmagnesium, are suppliedfrom the food fed to the fishand dissolved in the water. Inaddition, fish faeces breakdown to provide other essen-tial nutrients for the plants.In conventional aquacul-ture, the problem of keepingthe water fresh would require10 percent to be pumpedout daily to rid the tank ofsolids. For a 2000 litre tankthat amounts to 200 litres ofwater usage every 24 hours.Even if it were pumped onto

Up to 100 fish can be raised from 50 gram finger-lings to plate size (500 grams) over a six month pe-riod in a 3000 litre tank.

These plants are growing in blue metal which is acheap growing medium but, because it is heavierthan most, needs strong support.

Becoming moreself-sufficient

a conventional garden, it ismore than many farmerscould afford to use. Waterusage in an aquaponics sys-tem is far less and amountsto no more than replacingwater lost through evapora-tion and transpiration.So what does an aquapon-ics system look like? First ofall, it is surprisingly com-pact. A system that can pro-vide 50 kilogram of fish andover 100 kilograms of veg-etables in six months -enough to feed a small fam-ily - will easily fit under acarport roof. The size of thefish tank/pond/dam andgrowbeds can suit individualneeds, with some optionssmall enough to fit onto abalcony. However, a family-sized system would need afish tank of 2000 - 3000litres, plus three or fourgrowbeds. These need to sithigher than the fish tank, ei-ther by raising the growbedsor sinking the tank, to allowthe water to gravity feedback to a small drain tankthat can double as a finger-ling nursery until the maturefish are harvested. Fromthere the water is aerated andpumped back to the fishtank. Raising the growbedsalso reduces the risk of gar-den pests such as snails. Fur-ther refinements can includea battery backup for thepump or a worm farm toconsume vegetable scraps,with worms fed to the fish. A65 watt solar panel can re-duce or even eliminate thealready reasonable powercostsOnce each hour the

growbeds are flooded withwater pumped up from thefish tank. The pump stopswhen the tank water dropsto a level determined by afloat switch and the waterdrains back into the tankwithin the hour before beingpumped up again.The shape of growbeds isusually circular or rectangu-lar but should facilitate easyharvesting. They are filled to

a depth of 30 centimetreswith a growing medium thatcan be virtually any inertmaterial. Pea gravel, bluemetal, diatomite or ex-panded clay ‘pebbles’ arecommonly used.‘Expanded clay is probablythe best medium, but it ismore expensive than the oth-ers,’ Joel explains. ‘Bluemetal is cheaper but heavyand hard on the hands whenworking in the growbeds.’Normal reticulation pipe

and fittings, a small 200 wattpump and a couple of aera-tors complete the system.‘The tanks and growbedsdon’t have to be purpose-built,’ Joel explains. ‘Oldbaths or recycled food-gradeplastic barrels halved verti-cally are quite suitable.’The type of fish chosen de-pends on the climate and


Small FARMS 37May 2009

The water is aerated as it is returned to the tank.The level drops when the pump is operating, but israised when the water returns to the tank as thegrowbed drains.

In a symbiotic relationship this rainbow trout has as-sisted in the growth of the lettuces behind it, whilethe lettuces have helped clean the water in the fishtank. There is very little wastage from either prod-uct.

38 Small FARMS May 2009

personal preference. Joelgrows trout in the coolermonths, but Perth is too hotfor them in the summer, sohe then switches to barra-mundi.‘Six months is all that isneeded to produce a 500gram fish from a 50 gramfingerling,’ says Joel. ‘Fishhave a great food conversionrate: because they are cold-blooded, and because theyare suspended in water, theydon’t have to support theirown weight. Trout have a1.2:1 ratio.’A 3000 litre tank will carryup to 100 fish in this system.Some people prefer to keepornamentals, such as gold-fish or koi, while otherschoose silver perch, blackbream, yabbies or eels.‘Ethel Creek Station nearNewman in the Pilbara re-gion of WA have installed alarge aquaponics system,’Joel says. ‘It’s an ideal way forthem to have a constant sup-ply of fresh vegetables duringthe dry season. Overseasthere are aquaponics systemsin Alaska, as well as thedesert regions of the USA.’Apart from cleaning out thereticulation before replantingto remove roots that mayhave grown into thegrowbed pipes, Joel spendsjust minutes each day tokeep his system working.‘It takes less than five min-utes to feed the fish andcheck that it’s all workingOK,’ says Joel, ‘and they canlast without food for a cou-ple of days if I go away.’

Commercial growers arenow beginning to see thebenefits of aquaponics on alarge scale and Joel has re-cently installed a system ofperforated foam rafts float-ing on two 20 metre x 2.5-metre channels that willbring to maturity a continualharvest of 500 lettuces perweek. Grown conventionallythey would take more land,water, labour, and time tomature.As Joel says, aquaponics justmakes so much sense.

Backyard Aquaponics,telephone 08 9414 9334 orwww.backyardaquaponics.com


Black soldier flies occur naturally in the Perth re-gion. Their larvae live in compost and are self-har-vesting when appropriately housed. They make anexcellent organic food for the fish as do the casual-ties of ‘bug-zappers’ mounted over the tank.

This compact unit houses a complete aquaponicssystem with fish in the bottom chamber (opening onthe other side) and a single growbed on the top. Itwould easily fit on a balcony, patio or courtyard.

,I

Back-yard aquaculture refers to growout systems that are larger than home aquariums but less than about 0.4 ha in area. These systems are usually modeled after larger commercial growout systems. There is no limit to the variety of designs available for back-yard systems. They range from something as simple as a small stand-alone tank to very complex automated systems using sophisticated water treatment equipment.

System Types, Species Back-yard aquaculture can be generally classed according to

the water temperature. Coldwater aquaculture requires water temperatures of 10 to 21 0 C with the optimum temperature betlveen 12 and 1r c. The most popular species of fish grown in coldwater back-yard systems are trout and salmon.

Warmwater aquaculture requires water temperatures betlveen 18 and 32° C with the optimum temperature betlveen 27 and 30° C. The most popular species of fish grown in these conditions are bass, sunfish, catfish, tilapia and carp. Additional species can be considered in varied parts of the world.

Climatic conditions, geographic location and environmental factors must be considered when selecting the best species of fish for back-yard aquaculture. Tilapia, one of the easiest fish species to raise, is growing in popularity around the globe where climatic conditions and water temperature are right.

Tilapia can tolerate variable water quality, including fairly low dissolved-oxygen levels. In addition, tilapia grow relatively quickly on a low-protein diet and readily breed in captivity. They are fairly easy to handle and are widely accepted as food fIsh. In

global aquaculture advocate September/October 2009 87

Summary: With the downturn in the global economy, many new culturists are becoming interested in back-yard aquaculture systems. The level of sophistication required varies widely. Systems can range from simple stand-alone tanks to setups that require complex filtration, aeration and monitoring equipment. Aquaponics, the combination of aquaculture and hydroponics, is also ofgrowing interest.

, ... .. .

Some back-yard systems are rather complex and use a recirculating setup with fliters, aerators and other equipment.

\

Interest Rises In Back-Yard Aquaculture Options Range From Simple Organic Setups To ComplexAquaponics

Aquaculture has always interested hobbyists, and many have tried small-scale growout of fish in an aquarium, small pond or tank. Now, with the downturn in the global economy, there seems to be an increased interest in back-yard aquaculture. Individuals all )ver the world have demonstrated a renewed attention to growing :heir own food to supplement their needs. There appears to be a ~reat desire to be self-suffICient, and many are doing so by raising ~lsh on a small scale to provide for individual needs.

Aquaponics An increasingly popular type of back-yard aquaculture is

aquaponics, a combination of aquaculture and hydroponics for the production of both aquatic animals and plants. In aquaponics, the water is cycled from the fish tank into trays or beds holding plants. The plants utilize the nutrients in the water, and the "treated" water is returned again to the fish tank.

Greenhouse aquaponics can be fairly complicated, requiring a high level of management and equipment. Many of these backyard aquaponics systems use a recirculating setup. These systems include additional equipment like filters or clarifiers to remove solids, degassing columns, aeration systems and dosing systems that add chemicals required by the plants.

Some back-yard aquaponics systems are very simple but can still be very productive. The goal of many of these producers is organic food production. They desire an efficient system that uses little power while producing both fish and vegetables to eat. Because fish are living in the water, aquaponics systems are typically organic, and no herbicides, insecticides or fungicides are used.Aquaponics combines aquaculture and hydroponics

These systems can combine a variety of plants and fish for the production of both aquatic animals and plants. depending on location and conditions. Tilapia, trout, catfish or hybrid striped bass can be grown with vegetables such as tomatoes, lettuce, cabbage, beans, basil, peppers and cucumbers.

some areas, tilapia are preserved by drying or salting, and may be smoked or pickled. Additional Considerations

Back-yard aquaculture systems require special permits in System Components some locations. It is the owners' responsibility to become familMost back-yard aquaculture projects use recirculating sysiar with local and national laws regarding home aquaculture systems, although other systems have been developed for growout tems and determine if permits and/or registration are required. in cages, raceways and ponds. Some of the more popular water They should consider laws regarding water sources, water use containment approaches include aquariums, lined and unlined and wastewater discharge; permits required to hold, produce andponds, barrels, swimming pools, water troughs, and steel or sell fish; and laws regarding the location of back-yard aquaculfiberglass tanks. Water depths are usually about 0.75 to 1.00 m, ture facilities. although shallower tanks can also be used. -----

Because fish spend all of their lives in water, it is very important to maintain good water quality. If the water is not treated, An increasingly popular type ofback-yardvery little production may be expected. Aeration and filtration are required for increased production. Beginners often start with aquaculture is aquaponics, a combination lower densities of fish and increase production as they gain con ofaquaculture and hydroponicsfidence in their systems and equipment. It is also a good idea to for the production ofboth aquatichave emergency back-up systems to insure that aerators and pumps run during blackouts. animals and plants.

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88 September/October 2009 global aquaculture advocate

Wednesday 13th June 2007 • Conference Session 2

Research Into An Energy FromFood Waste Scheme That PowersAn Aquaponics Sustainable FoodProduction Business

Keywords: Algal Harvesting, AnaerobicDigestion, Aquaponics, Bio fuel, Energyfrom Waste, Gasification, QuintupleGeneration, Rainwater Harvesting.

IntroductionThere are four main drivers that haveled to this current research topic:

• Most UK Local Authorities’ currentattitude to the disposal of organicfood waste - is to continue to sendto landfill whilst space and costpermits or to incinerate

• Developments in technology arenow making feasible new systemsand methodologies for combiningwaste and food production as anintegrated system

• An increase in chaotic weathersystems is destabilising many partsof the environmental ecosystem andmaking controlled crop productionunpredictable

• The aspiration to turn publicperception of organic waste as aproblem to one of a valuableresource.

The larger the size of a community thegreater the problems it creates - such aswaste generation and disposal, energyconsumption, transport congestion andproviding constant food supplies to thepopulation. All produce pollution thatgradually degrades the quality of life forthe inhabitants.

So far, waste and energy generation plusfood production have been viewed asseparate areas with their ownspecialisations. This has led to completestasis in planning frameworks for highdensity living environments. London is agood example demonstrating a lack ofjoined-up thinking, with differentboroughs choosing very differentsolutions to these problems. The netresult is that planning has not beenvisionary enough to cope adequately withwaste disposal, onsite energy generationor urban food production, resulting incontinuing unnecessary transport costsand subsequent CO2 emissions.

Tackling the Food Waste StreamDespite food waste being one of thelargest single components of the UKwaste stream, only 2% is collectedseparately for composting or anaerobic

digestion [Burke, 2007]. UK foodmanufacturers produce around 6.2million tonnes of food waste per annumand households 7.5 million tonnes(approximately 216 kg per household)[DEFRA, 2006]. At present 80% of this issent to landfill and with the average costof landfill at £65 per tonne (and rising)this equates to £712 million per year.

The reasons are complex but stem allthe way from Local Authorities’inexperience in delivering a captivatingmessage to their householders on whyseparating organic waste at source isgood for the environment and cuts theircouncil tax bills.

Apart from damage to the environment,throwing away uneaten food also wastesmoney. Current figures indicate thateach week a typical household throwsaway between £4.80 and £7.70 ofuneaten food; this is equivalent to£250-£400 a year or £15,000-£24,000 ina lifetime [DEFRA, 2006].

Food Supplies Under ThreatIronically, whilst the UK and many otherwestern countries are throwing awayfood they are concurrently facing an

Originally from Scotland, Liam Devany is a mature student who returned topostgraduate education and obtained his MSc in Advanced Environmental andEnergy Studies at the Centre for Alternative Technology, Wales / University ofEast London. His background working experience spans energy generationsystems, IT, wireless communications, horticulture, vermiculture andenvironmental building.

He is currently in his last year of a PhD funded by the EPSRC at the Universityof West England, specialising in urban food production systems within the BuiltEnvironment - with a particular emphasis on apiculture. In the next stage of hispost-doctoral research Liam intends to concentrate on mainstream sustainableurban food production systems which combine traditionally separate fields intoclosed-loop systems that have scalable potential.

He has also founded two social enterprises since the turn of the decade and iscurrently a director of HBC - an environmental charity that is involved withgreen community building projects, urban food production systems andrecycling initiatives.

Liam Devany


impending food supply shortage in thenext 25 years at current rates [Viner andWallace, 2005]. To comply with theEEC’s Common Fisheries Policy (CFP)European fishing fleets reduced by 30%up to 2003 [Nautilus, 1997], which willrise dramatically as fishing stockscontinue to decline. Pessimistic globalforecasts predict complete extinction ofour edible fish by around 2050. Stockshave already collapsed in nearly one-third of sea fisheries, and the rate ofdecline is accelerating. See Figure 1below. In 2003, 29% of open seafisheries were in a state of collapse, i.e.producing less than 10% of theiroriginal yield.

Agricultural farming also faces severalthreats. UK farmers supply around 90%of UK potato consumption, 70% ofother vegetables, but only 10% of fruit[EAFL, 2006]. Urban population spill isconsuming increasing agriculturalacreage; with farmhouses becomingattractive second property buys forwealthy urbanites, making surroundingfarmland redundant.

The Worldwatch Institute paints a bleakpicture of erratic weather playing havocwith crop production - rearrangingtraditional planting and harvestingtimes, longer drought periods creatingproblems for watering crops sufficiently,alongside the type and volume of insectpredation on crops [Deweerdt, 2007].Such conditions make it difficult toguarantee crop volumes and quality,making smaller-scale arable farmingincreasingly less viable financially.

Precision Food ProductionTo counter the forecast food shortages,it will be necessary to take control offood production so that cities canadequately produce enough fish,vegetables and fruit to a consistentvolume and schedule. This requiresmoving fish farming inland and placingvegetable crops undercover to be

grown hydroponically, whilst striving toproduce all food stocks organicallyrather than chemically (inorganic).

Fortunately, there are alreadyestablished methods for doing this. Inthe UK, aquaculture mainly uses open-air methods to rear cold-water fish suchas salmon in lakes and trout in ponds.Indoor aquaculture is rare because ofthe high costs of utilities, but canconsistently produce large volumes offresh water fish that prefer warm water -such as Tilapia and Barramundi.

Traditionally, aquaculture and hydroponicshave been seen as separate foodproduction processes and both haveserious drawbacks with high waterconsumption and the toxic run-offpollutants each process generates. Themost common chemical run-offconstituents are calcium, magnesium,phosphates, nitrates, sulphate andpotassium [Winterborne, 2005]. Thereliance on these chemicals to ensureconstant production results in produce,often described as bland tasting, thatconforms to supermarket standards thatcannot be sold at a premium pricebecause it cannot be classified as organic.

AquaponicsThe science of combining bothprocesses on a commercial scale isrelatively new and has only establisheditself commercially since the 1990s.Aquaponics is the name coined todescribe this combination: (Aqua) fromAquaculture and (ponics) fromHydroponics. It should be noted thatthe aquaculture aspect of this project isdefined as the growing of fish in indoortanks as opposed to cages in outdoorponds or lakes. By combining bothprocesses the run-off pollutants areneutralised and turned into a resourceas well as being contained within acircular recycling process.

Data from areas where fishing has beenbanned or heavily restricted shows thatprotection brings back biodiversity withina zone, and restores populations of fishjust outside it [Viner and Wallace, 2005].Aquaponics can act as a respite fromextensive sea over-fishing and allowalternative fish types to be introducedinto the market whilst traditional stocksare allowed to build up.

Hence young fish (spry) are purchasedthen grown over a period of severalmonths to optimum market size. Thepreferred fish is Nile Tilapia(Oreochromis niloticus) because of itsrobustness in handling changing waterconditions and being able to exist

comfortably in high density as it does inthe wild. Tilapia is the most consumedfish globally but is unknown in northernclimates as it thrives in watertemperatures between 80-900F.However, there is already an establishedmarket in the UK servicing an ethnicpopulation accustomed to this fish -with two of the major supermarketchains (Sainsbury’s and Morrison)already selling it at their fresh fishcounters. Consumption of Tilapia in theEurope is expected to increase as it isrelatively neutral in taste and provides asuitable substitute for traditional UK fishstocks such as cod, plaice, sole andherring as they decline over the next 20years [Nautilus, 1997].

Tilapia is omnivorous and can be fedplants such as Duckweed within theoperation [Sell, 1993]. Whether thisoption would be chosen would dependon the scale of the operation and thepremium price paid for organicallygrown fish. Aquaponics requires spaceat a ratio of 1:7 of fish to hydroponicsproduction [Rakocy and Hargreaves,1993]. As the volume of space requiredto feed the fish organically can probablybe used to grow more profitable food orpharmaceutical crops hydroponically, it islikely the farmer would directly feed fish.

The Process CycleIn commercial aquaponics the wastegenerated by the fish is extracted fromthe bottom of the tank then held intanks as micro organisms break downthe high concentrations of nitrites tonitrates [Naylor et al, 1999], thenpumped through a hydroponics growingsystem providing a nutrient source forvegetables and fruit. [Worthington,2001] compared mineral levels betweenorganically and inorganically growncrops and found the former containedless nitrates and contained significantlymore vitamin C, iron, magnesium andphosphorous than the latter. Precisioncontrol of nutrients can develop newtypes of marketable crops. Ahydroponic farmer in Virginia hasdeveloped a calcium and potassiumenriched head of lettuce, scheduled forsale Spring 2007 [Murphy, 2006].

After plants extract nutrients the water itis mechanically and UV filtered thenrecirculated back to the fish tanks thatare constantly aerated. Only 10% ofnew water is added to the cycle weekly,making it highly efficient in waterconservation [Bugbee, 2003]. A filteredrainwater harvesting system from thepolytunnel roof can be fitted in areasthat have sufficient rainfall to removereliance on mains water supplies.

Figure 1: Global loss of seafood species


A complimentary cycle is thusestablished, fish use oxygen and giveoff carbon dioxide when they breatheand their waste contains nitrogen forplants. Adding algae works in reverse asthey use carbon dioxide and give offoxygen whilst using nitrogen in fishwaste with light and carbon dioxide togrow. See figure 2 below.

Algal BiofuelA proposed innovation is the integrationof a process utilising the particularmicroscopic green algae -Chlamydomonas reinhardtii - commonlyknown as pond scum. Recentbreakthroughs in controlling andincreasing the algae’s hydrogen yieldpresent the possibility of it beingharvested for bio diesel [Vertigro, 2006].In this process, holding tanks are fedwith fish waste nitrates and air dosedwith CO2 into enclosed photobioreactor tanks containing light platesto enhance thick algal growth. It hasbeen shown that the maximumproductivity for a bioreactor occurswhen the exchange rate (time toexchange one volume) is equal to thedoubling time of algae growth [Sheehanet al., 1998].

Excess culture overflows and is harvestedusing micro screens. When algae is driedit retains its oil content and can then bemachine-pressed to yield oil that can beconverted into bio diesel, with theremaining dried fraction used as anutrient rich fertiliser [Walker et al, 2005].Alternatively it could be directly burnedto produce heat and electricity.

The algal-oil feedstock used to producebio diesel can be used directly for fuelas "Straight Vegetable Oil", (SVO).Whilst using the oil directly does notrequire the additional energy neededfor transesterification, (processing the oilwith an alcohol and a catalyst toproduce bio diesel), it does require

modifications to a diesel engine,whereas bio diesel will run in moderndiesel engines unmodified. The per unitarea yield of oil from algae is estimatedto be from between 5,000 to 20,000gallons per acre, per year - this is 7-31times greater than the next bestyielding crop - palm oil (635 gallons)[Sheehan et al., 1998].See figure 3below. The system will be a continuousclosed loop, which allows for a greaterretention of water in the system, andeliminates cross contamination by otheralgae species.

Pollution ControlAs much of the CO2 released into theatmosphere comes from burning fossilfuels, this method provides a thoroughand efficient capture by attaching aphoto bioreactor to any fuel burningplant, the CO2 produced duringcombustion can be fed into the algaesystem. With plant nutrients beingsourced from fish sewage, two pollutantsare thus turned into resources for theproduction of bio fuel, with a footprintrequirement far less than other crops.

Combining Traditionally AlienSectorsAlthough commercial aquaponicsoperations (without the algaecomponent) can already be found inwarm climates such as the southernUSA, South America and Australia, theyhave not been able to establishthemselves in northern climatesbecause of the additional large utilitycosts incurred - such as electricity forlights, pumps and heating - to keepthem operational. The main propositionof this paper combines an energy fromwaste (EFW) method with anaquaponics food / algal fuel operationto provide a "complete loop" recyclingprocess - whilst being viable financially.

Both processing plants should beadjacent to each other to eliminate

transportation costs whilst obviouslyretaining biosecurity standards andconforming to AFBP regulations. Thefeedstock is household organic foodwaste that is combined with wastederived from filleting fish and thepreparation of hydroponicsvegetable/fruit produce for sale. TheEFW method in conjunction with acombined heating and power unitwould service the full energyrequirements (heat, cooling andelectricity) of the growing operation,with excess electricity (depending onsize of operation) either poweringoccupants homes or being sold to thegrid at a premium “green” price.

Quintuple GenerationCurrent technologies for EFW that areapplicable are gasification andanaerobic digestion. The system canutilise quintuple-generation (QG)methods to produce biogas, heat,refrigeration, electricity & bio fuel tomaximise energy and food output mostefficiently. QG’s superior efficienciessurpass “state-of-the-art” combinedcycle cogeneration power plants by upto 50% [Goodell, 2007]. Coupled with a4-pipe system, this process produceshot water/steam and chilled watersimultaneously, for circulationthroughout a high-density building orvillage. By integrating refrigeration intothe system fresh fish / vegetable stockscan be chilled or frozen whilst awaitingconsumption.

Size is not an impediment, as any scalewill still remain at system efficiencies of90% [Soderman, 2002]. A systemintegrated into urban/commercialbuildings could pay for itself in just 2years, depending on local electric rates,natural gas (or other fuel) costs, and theload profile of the building.

There follows a brief discourse outliningthe benefits and disadvantages of thetwo main EFW processes for treatingfood waste, although it must be notedthat very few plants currently inoperation are exclusively processingfood waste.

Figure 2: Schematic of Aquaponics food production process, 2007

Figure 3: Oil yields © NREL, 1998


Anaerobic Digestion (AD)AD is the preferred solution for smalleroperations on a cost basis. Atemperature-phased digester combinestwo types of digestion technologies(mesophilic and thermophilic) into atwo-stage reactor, increasing methaneyields. In general, operations servicingmore than 450 people (150 households)are able to benefit from economies ofscale, with installation costs around£200 - £250 per head [Davidsson et al.,2007]. Previously, systems without wasteheat recovery used around 30% of thebiogas they produced to heat their owndigestion process. The energy contentof the waste heat must be high enoughto be able to operate equipmenttypically found in trigeneration powerand energy systems such as absorptionchillers, aerators, heat amplifiers,dehumidifiers, hot water heat pumps,turbine inlet air cooling and othersimilar devices.

Although more expense in householdereducation is required for separation oforganic waste at source, the capital set-up costs are less compared to thermalbased methods. Such an installationwould be appropriate for smallcommunities or large tower blocks -where integration into the building is thepreferred route. The food, algae andrainwater harvesting is located on flatroofs under lightweight polytunnelstructures to maximise sunlight exposureand conserve energy requirements.

Meanwhile food waste moves down thebuilding in gravity chutes to the ADplant located in the basement. The gasproduced powers turbines, and a CHPunit utilises the heat generated for theliving quarters and the food growingoperation on the roof. Good soundinsulation (highest sound emissionsoccur in the encapsulated generatorand amount to around 80 dB (A) at adistance of 1 metre), efficient fractionseparation and odour control are thetechnical challenges in this type ofinstallation.

Conversion of this biomass intocombustible gas also has all theadvantages associated with usinggaseous and liquid fuels such as: cleancombustion, compact burningequipment, high thermal efficiency anda reasonable degree of control.AD harnesses and contains naturallyoccurring process of decomposition totreat the waste and produce biogas thatcan be used to power electricitygenerators, provide heat and producesoil ammendments. A temperature-phased digester combines two types of

digestion technologies (mesophilic andthermophilic) into a two-stage reactor,increasing methane yields. In the UK,five plants were currently operationaland another six in various planningstages at the end of 2006 [AD, 2006]but none within buildings.

AD has three main applications for builtenvironments:

• It’s a proven waste disposaltechnology which appeals to WasteAuthorities as they enter contracts tobuild new waste managementfacilities

• Agricultural Waste Management andproduction of fertiliser and on-farmbiogas

• Renewable energy generationassuming current (Spring 2007)energy prices are maintained.

If the 5.5 million tonnes of UK municipalfood waste were targeted for separatecollection, then the total quantity ofelectricity generated would be in theregion of 477-761 GWh per annum ifthe material was digested. This isequivalent to the electricity used bybetween 103,000 - 164,000 households,or 16-26% of the energy generated bywind power in the UK in 2005 [Keay,2005]. Composting the same amount ofmaterial would utilise energy in theprocess.

The net position in respect ofgreenhouse gases is likely to be suchthat routing the material through ADrather than composting will improve theposition in respect of greenhouse gasesin the region of 0.22 - 0.35 milliontonnes CO2 equivalent (based on anassumption that the displaced source isgas fired electricity generation). Ifequivalent biomass had been landfilled, savings increase to 1.6 - 3.6million tonnes CO2 equivalent,depending upon the performance ofthe landfill and the digester.

Benefits of Anaerobic Digestion• Because the process is contained,

odour is controlled, which can helpmeet permitted limits on emissions

• AD destroys more volatile organiccompounds and produces more gasthan traditional compostingmethods used e.g. for the treatmentof sludge

• AD produces less solid waste, andwhat is produced can be useddirectly on fields as a mulch or soilamendment

• Biogas collected from the processcan be used to offset energy costsby providing heat, running

refrigeration, supplying processheating and producing electricityand steam

• Using biogas reduces fossil fueldependence thus reducing pollutiongenerated by drilling, mining,transportation and emissions,including methane and CO2.

Disadvantages of AnaerobicDigestion• Purchase and installation is more

expensive than closed windrows • Additional plant, time and labour are

required at the front end to ensurepurity of the feedstock. Any plasticor synthetic material contaminationcan shut down the AD flow

• Requires water supplies - althoughsome water costs can be mitigatedvia a good rainwater harvestingsystem

• Although the plant requires arelatively small footprint, labour andspace for separating incoming wastecan be considerable

• Although not as foul as closedwindrows, the odour surrounding anAD plant is still unpleasant to workin.

PyrolysisThe other route to utilising food wastefor EFW is a thermal conversion processcarried out in the absence of oxygen,yielding solids, liquids and gases.Within the context of electricitygeneration, slow pyrolysis that yields acarbonised product can be used as apre-treatment step before gasification.The intermediate product has welldefined characteristics, offering severaloptions for power production.

Pyrolysis of waste is mainly carried out asa pre-treatment for high temperaturecombustion or gasification processes.Due to the uniformity of the carbonisedproduct, better control of the thermalconversion process is possible. As costsdrop for cleaner and/or precisioncontrolled systems in the medium tolong-term, the importance of pyrolysis asa pre-treatment step is likely to increase.

GasificationThis occurs when a solid or liquidsubstance is transformed into a gaseousmixture by partial oxidation with theapplication of heat (pyrolysis). Theprocess is optimised to generate themaximum amount of gaseousbreakdown products, typically carbonmonoxide, carbon dioxide, hydrogen,methane, water, nitrogen and smallamounts of higher hydrocarbons. If allthe UK’s food waste was processedthrough pyrolysis/gasification methods it


could generate up to 6 billion kW hrs ofenergy - which equates to enoughenergy to power 1.3 million houses peryear (based on UK averageconsumption figures) [Atari, 2004].

Its prime advantage is it can flexiblymanage contaminated feedstock.Packaging, along with various organicfractions, can be directly fed into theprocess without pre-separation. Thissaves on labour costs and storage spaceand makes collection an easierproposition for local authorities, withlittle education of the householderrequired. It is also a more suitable EFWmethod for large foodmanufacturing/sales operations requiredto dispose of out-of-date products fromsupermarkets compared to the costs ofseparating organic waste frompackaging using AD.

DisadvantagesWhilst gasification is a process optimisedfor the maximum yield of gases, it stillgenerates solid and liquid by-products asa result of the reduction of organicmatter, which may contain high levels oftoxic contaminants. A previous review ofpyrolysis systems by CADDET (1998)raised concerns about residues fromthese processes. Mohr et al. (1997) foundthat dioxins and furans were formed inthe cycle producing high levels in liquidprocess residues. Weber and Sakurai(2001) examined the formation of dioxinsand furans under pyrolysis conditionsand concluded that they were definitelyformed from wastes containing chlorineand copper. However, contemporarythermal treatment process plants witheffective gas scrubbing can reduce theemissions of acid gases, heavy metalsand dioxins and furans to levels wellbelow the EU Waste IncinerationDirective emission limits.

Capital costs are therefore significantlyhigher at the backend, with extra plantrequired to deal with NOX and toxicwastewater. It’s likely much of this“cleansing” equipment may not berequired when supermarkets and foodsuppliers move over to 100%biodegradable point of sale packaging,e.g. biodegradable cardboard withcornstarch windows packaging. At thatpoint reduced costs of smaller-scalegasification/CHP plants would allowinstallation in the basements of largemunicipal buildings and housing blocks.Until then the costs for this process willremain higher than AD.

Gasification stands or falls by how ithandles its waste by-products. It iscurrently more appropriate as a large-scale EFW technology that closelyfollows the traditional centralisedcollection model utilised by combustionpower stations for over fifty years. Alliedto a large-scale aquaponics operationlocated alongside this plant,economies-of-scale and productivitybenefits will be considerable. Thenecessary plant distance from urbancentres means there are no savings ontransport fuel costs compared againstexisting food and waste collection anddistribution methods.

Environmental BenefitsAquaponics, AD and gasification

methods have the benefit of offsettingthe use of fossil fuels such as coal andnatural gas. As the waste materialsprocessed are organic matter, they canbe considered carbon neutral and theirdiversion from landfill also reduces landand water pollution and prevents therelease of methane - which is 22 timesmore atmospherically damaging thanCO2. By using this process it is estimatedthat landfill methane emissions could bereduced by many metric tonnes ofcarbon, equivalent to having planted (x)acres of forest or removing the annualemissions from (x) cars.

ReferencesAGSTAR Handbook (2006) Questions that need to be asked andanswered before investing your money. UW-Extension, University ofWisconsin-Madison -http://www.epa.gov/agstar/resources/handbook.html

Anaerobic Digestion Plants in the UK (2007) -

http://www.anaerobic-digestion.com/html/ad_plants_in_the_uk.html

Animal By-Products Regulations (2005) -http://www.defra.gov.uk/animalh/by-prods/default.htm

Atari, G. (2004). Food waste as a resource. In ‘Biogas – how to sustainoutput from today’s number one renewable’. Renewable PowerAssociation Conference, London.

Bini, R. and Manciana, E. (1998) Organic Rankine Cycle Turbogeneratorsfor Combined Heat and Power Production from Biomass. InProceedings of the 3rd Munich Discussion Meeting, Munich, Germany.

Bugbee, B. (2003) Nutrient Management in Recirculating HydroponicCulture. South Pacific Soil-less Culture Conference Feb 11, PalmerstonNorth, New Zealand.

Burke, D.A. (2007) Dairy Waste Anaerobic Digestion Handbook. -http://www.makingenergy.com

Davidsson, A., Jansen, J.L., Appleqvist, B., Gruvberger, C. and Hallmer,M. (2007) Anaerobic digestion potential of urban organic waste: a casestudy in Malmö. Waste Management Research.; 25: pp. 162-169.

Deweerdt, S. (2007) Climate Change, Coming Home: Global warming’seffects on populations. World Watch Magazine, May/June, vol. 20, no. 3.

DEFRA UK Statistics (2006) -http://statistics.defra.gov.uk/esg/publications/efs/default.asp

EAFL (2006) Fruit and Vegetable Production. Report for East AngliaFood Link Network.

FAO (1994) Integrated energy systems in China - The cold Northeasternregion experience. Food And Agriculture Organization Of The UnitedNations, Rome, 1994.

Goodell, M. (2007) Trigeneration Advantages For Commercial &Industrial Clients. Trigeneration Technologies. -http://www.trigeneration.com/

Grubb, M., Butler, L. and Twomey, P. (2006) Diversity and security in UKelectricity generation: The influence of low-carbon objectives. Faculty ofEconomics, University of Cambridge.

Healthcare Without Harm (2007) Pyrolysis - a non-traditional thermaltreatment technology. -http://beehive.thisisderbyshire.co.uk/default.asp?WCI=SiteHome&ID=890&PageID=7886

IEA CADDET (1998) Advanced Thermal Conversion Technologies forEnergy from Solid Waste. A joint report of the IEA BioenergyProgramme and the IEA CADDET Renewable Energy TechnologiesProgramme.

Keay, M. (2005) Wind power in the UK: Has the SustainableDevelopment Commission got it right? Oxford Energy Comment,Oxford Institute for Energy Studies, May.

Mohr, K., Nonn, C.H. and Jager, J. (1997) Behaviour of PCDD/F underpyrolysis conditions. Chemosphere 34, pp. 1053-1064.

Murphy, K. (2006) Farm Grows Hydroponic Lettuce. Observer Online.

Naylor, S.J., Moccia, R.D.and Durant, G.M. (1999) The ChemicalComposition of Settleable Solid Fish Waste (Manure) from CommercialRainbow Trout Farms in Ontario, Canada. North American Journal ofAquaculture, vol. 61:pp. 21–26.

Nautilus Consultants (1997) The Economic Evaluation of the FishingVessels (Decommissioning) Schemes. Report on behalf of The UKFisheries Departments.

Oswald, J. I. & Oswald, A.J. (2006) The Spatial Requirements ofRenewable Energy

Rakocy, J.E. and Hargreaves, J.A. (1993) Integration of vegetablehydroponics with fish culture: A review.

American Society of Agricultural Engineers, St Joseph, MI (USA), pp.112-136.

Schultz, M.G., Diehl, T., Brasseur, G.P. and Zittel, W. (2003) Air pollutionand climate-forcing impacts of a global hydrogen economy. Science,302, pp. 624-627.

Sell, R. (1993) Tilapia. Report for the Department of AgriculturalEconomics, Alternative Agriculture Series, no. 2, NDSU.

Sheehan, J., Dunahay, T., Benemann, J. and Roessler, P. (1998) A LookBack at the U.S. Department of Energy’s Aquatic Species Program:Biodiesel from Algae. National Renewable Energy Laboratory ReportTP-580-24190.

Soderman, M.L. (2002) Including indirect environmental impacts in wastemanagement planning.

Department of Energy Conservation, Energy Systems TechnologyDivision, Chalmers University of Technology, Goteborg, Sweden

The Energy Blog (2006) Vertigro Algae Bio-Fuel Oil/C02 SequestrationSystem. October 07 -http://thefraserdomain.typepad.com/energy/2006/10/vertigro_algae_.html

Thankappan,S. (1999) From Fridge Mountains to Food Mountains?Tackling the UK Food Waste Problem.

UNDP (1999) A Revolutionary Pyrolysis Process for turning Waste-to-Energy. BIO ENERGY NEWS, vol. 3, no. 4.

Viner, D. and Wallace, C.(2005) The Impact of Climate Change on CropProduction and Management - Now and in the Future. Climate ResearchUnit Report, University of East Anglia, UK.

Walker, T.L., Purton, S. Becker, D.K., Collet, C. (2005) Microalgae asbioreactors. Plant Cell Reports,

Springer-Verlag 2005.

Weber, R. and Sakurai, T. (2001) Formation characteristics of PCDD andPCDF during pyrolysis processes. Chemosphere 45, pp. 1111-1117.

Weiland, P. (2000) Anaerobic waste digestion in Germany - status andrecent developments. Biodegradation. 11(6): pp. 415-21.

Winterborne, J. (2005) Hydroponics - Indoor Horticulture. Pukka Press,Guildford, UK.

Worthington, V. (2001) Nutritional quality of organic versus conventionalfruits, vegetables and grains. Journal of alternative and complimentarymedicine, vol. 7, part 2.

Issue 21, June 2008 www.crcsalinity.com.au/spa

INSIDE:

NEWS FROM THE CHAIR 2

INDUSTRY NEWS AND EVENTS 3

FARMER CASE STUDY 4

John and Bernadette Cashmore, East Hyden

RESEARCH

Aquaponics 6

Saltland Capability 8

CRC UPDATE 9

INFORMATION 10

Disclaimer: Views expressed are not necessarily those of the Project Manager or the Committee of the Saltland Pastures Association Inc. (SPA). All information is provided in good faith. No liability will be accepted by SPA for any loss or damage suffered as a result of applying information given in the SPA newsletter. Mention of trade names does not imply endorsement or preference of any company's product by SPA and any omission of trade name is unintentional.

This newsletter is proudly sponsored the National Landcare Programme’s Community support

component.

Aquaponics – new opportunity for saltland? Page 4

SPA Update Glenice Batchelor, SPA Chair

It’s been a busy couple of months in the chair with a number of highlights.

International Salinity Forum in Adelaide In April I attended the International Salinity Forum in Adelaide to present a paper and proudly listened to Sally Phelan (Project Manager) and Michael Lloyd copresent a paper on SPA’s behalf. The paper outlined the Saltland Revegetation Initiative which encompasses the National Landcare Programme funded Grower Support Network project in the Avon and South West catchments, as well as Avon Catchment Council’s saltbush and saline pastures subsidy project.

The SPA committee were very pleased to source funding through Land Water and Wool to sponsor four farmer members from around the state to attend the Forum thanks to the generosity of Land, Water and Wool. It was great to meet Bernadette Cashmore (East Hyden), Andrew Lee (Dumbleyung), John Pickford (Woodanilling) and of course to allow Michael Lloyd to attend and copresent. All have assured me it was a valuable and enjoyable learning experience. Andrew Lee will give a grower’s perspective of the conference in the September newsletter.

Tony York from Tammin was a key presenter and rounded out the amazing four days by sharing his family’s experiences using saline pastures in their farming system with the international audience. WA was strongly represented at the conference and reflected the amount of excellent research and researchers we are so lucky to have here in the west such as Hayley Norman (recently featured on Landline), Ed BarrettLennard, Di Mayberry and Phil Nichols.

Pathways to Adoption Workshop Last year a very successful Pathways to Adoption workshop was held at Katanning and it was wonderful to be able to bring the workshop to the eastern wheatbelt and host it at Tammin/Kellerberrin. Check out the John Powell update in this newsletter. For me, the workshop reinforced the role of saltland pastures in our farming systems.

SPA Staff Update Project Manager Sally Phelan’s contract will be ending in June and Sally will return to the Department of Agriculture and Food (DAFWA) based at the Bunbury office. Sally will still be working for SPA for three days a week to the end of September, which will help finalise current projects and assist with the transition to new projects and handover to new staff. Our thanks go to DAFWA for their ongoing assistance and support.

The six Grower Support Network advisors will continue to assist growers in the Avon and South West catchments to the end of the year.

National Landcare Programme Sustainable Practices funding SPA have submitted a joint funding submission with Evergreen Farming and WA Lucerne Growers which looks at increasing adoption of perennials across the landscape, regions and rainfall zones. If successful, the project will evaluate the benefits of the three groups joining to form one WA perennialsfocussed organisation. Whether or not an amalgamation occurs, the project will strengthen partnerships and provide some great on ground outcomes for WA farmers. Member consultation and support will be an integral part of exploring future partnerships.

Regional NRM groups SPA has been maintaining regular contact with regional groups to see how the change of Federal government is affecting their futures. We remain committed to working within the regional framework wherever possible and that the regional process is important to ensure that local needs are recognised and where possible supported.

SPA Committee We will be meeting this month and as always we welcome any input to any of our committee. This year we are focussed on future planning and project development and continuing to meet the needs of our members.

On a personal note, I am very proud to have been acknowledged as the WA Landcare Professional at the State Landcare awards. The opportunity to work with likeminded individuals and groups is something that all of us appreciate and I’d like to thank everyone who has worked with me over the years.

News from the Chair

Land Water and Wool sponsored SPA members to attend the International Salinity forum. From left: John Pickford (Woodanilling), Michael Lloyd (Pingaring), Bernadette Cashmore (East Hyden), Mike Wagg (Land Water and Wool), Glenice Batchelor (SPA chair) and Hayley Norman (CSIRO Livestock Industries)

2

You are invited to the following:

Albany Seminar ‘Developing commercial opportunities for tree and perennial crops on saline lands in the Great Southern”

Thursday 26 th June 2008 8.30am – 12.30am

At the Department of Agriculture and Food Seminar room, Albany Highway

Green Skills, in association with Timber 2020, South Coast NRM, Forest Products Commission and the CRC for Future Farm Industries, is running a major seminar in the Albany region on Thursday 26th June 2008.

When: Thursday 26 th June 8.30 – 12.30

Focus: Developing new tree and perennial plant commercial opportunities for saline lands. This seminar is being run under the Green Skills’ Dryland Farm Forestry program funded through South Coast NRM. The idea follows on from a regular annual program of seminars we have coordinated since 2001. This seminar is aimed at farmers pioneering new approaches to tree cropping and adoption of perennials on saline lands, agency and plantation sector reps, NRM reps, and interested members of the general public.

Morning Tea and Lunch provided

Cost: $30 Corporate and Organisational $20 individual $10 concession (includes GST)

For further information contact Basil Schur 9848 1019 Email [email protected]

Advertise in the SPA Newsletter

Reach your target audience!

Full page $100.00 Half page $75.00 Quarter page $50.00

To advertise, contact Sally Phelan on 0427 902 126 or [email protected].

Industry news and events

SPA Fact Sheets

Direct Seeding, Old man saltbush, River saltbush, Wavy leaf saltbush.

For copies, contact Sally Phelan on 0427 902 126 or [email protected].

3

Biodynamic farming helps saltland recovery Biodynamic farming is about much more than just ‘not applying chemicals’. It is an involved process of feeding the soil to increase soil biota and organic matter, thus producing rich humus. Conventional agriculture fertilizes to directly feed plants, whereas in biodynamics, special preparations are applied to feed the soil, and healthy soil produces healthy plants, which in turn grows healthy animals. Although biological farming techniques like organics and biodynamics have become popular with health conscious consumers in recent times, John and Bernadette Cashmore at ‘Nyonger’ east of Hyden have been farming biologically since 1992. And the benefits have not just been on their fresh soil. John and Bernadette have also noticed a significant improvement in their saline landscapes.

John and Bernadette Cashmore farm a 4,800 acre property 40km east of Hyden, just one property away from the rabbit proof fence. John has always worked on the farm, gradually taking over from his father during the 1980’s. It was noticed that conventional farming methods were degrading the property resulting in the rapid expansion of salt pans and scalds. While investigating biodynamics, John and Bernadette were advised that it may take time to bring the farm back, but with persistence soil improvements have been excellent and the Cashmores gained Demeter certification in 1995 – just three years after introducing the “nature enhanced” organic method on the farm.

John and Bernadette will grow 900 acres of barley this year, with the rest in pasture. When clovers reach a high level in the pasture, the soil is ready for a cropping phase. If a crop is not grown at this stage, grasses will predominate next season. The level of clovers in the pasture guides the rotation, as opposed to specific phases. Paddocks are grazed hard before a crop to reduce weeds, which are now not a big problem. John and Bernadette have recently moved into growing and marketing ‘Cashmore Meats’ certified biodynamic lamb. With low wool prices in recent years, the Cashmores have been slowly moving to Dorper sheep and are finding them to be more resilient.

In 2000, John and Bernadette compared DOLA aerial photos taken of their saline land in late October in 1994 and 1999. In 1994, the saline site had received three application of the

biodynamic spray BD 500, and in 1999 the same site had received eight sprayings. What John and Bernadette observed was a significant improvement in the condition of the saltland. While two dry years preceded the 1994 photos, five wet years preceded the 1999 photos. It would be expected that the wet seasons would have increased the salinity; however the opposite was observed (photos 1 and 2). In comparison, the conventional farm next door was showing an increase in the area of salinity (photos 3 and 4).

John and Bernadette believe the dramatic improvement on the saline sites is due to the soil structure benefits of applying BD 500. Compacted soil tends to create capillary action, drawing salts to the soil surface and creating scalds. Research from La Trobe University at the Cashmore’s has shown an improvement in soil structure across the farm, and fluffy, friable soils with rich humus have been observed. This recreation of soil structure and top soil has acted like mulch creating a freshening of the soils surface and allowing plant growth.

John and Bernadette are this year participating in the SPA Avon Saltbush planting scheme. They will be growing old man and river saltbush seedlings, and are also keen to try some direct seeding to see whether the biodynamic methods assist with a successful establishment. It is hoped that the water use from the saltbushes will complement the soil structure improvements observed from biodynamic methods.

For more information visit http://members.bordernet.com.au/~cashmore3

Farmer Case Study Farmer Case Study

Before and After. Photo 1, left, saltland in 1994 after three BD 500 sprays. Photo 2, right, the same area of saltland in 1999. The area of salinity is greatly reduced after eight sprays of BD 500.

4

Farmer Case Study

Photo 3

Conventional versus biodynamic, 1994. Area of saltland circled in red for biodynamic, and blue for conventional.

Photo 4

Conventional versus biodynamic, 1999. Area of saltland increased in conventional paddocks (blue) but decreased in biodynamic paddock (red).

Pink ‐ Conventional Yellow ‐ Biodynamic

5

Salt Water Aquaponics: growing fish and saltland pasture together

A trial has begun in the wheatbelt on a property near Goomalling that may totally change the way farmers view their salt affected land. On this cereal/sheep property an area that has been severely affected by salinity has been allocated to carry out the trial.

The company Aqua Farms Research and Development (AFRD) have dug several trenches, each of about a million litres into the watertable where the salinity is two thirds to full sea water ( 20 – 35 ppt). AFRD are trialing a system to farm marine fish such as Mulloway, Pink Snapper, Black Bream and salt tolerant rainbow trout in intensive cage systems. The system uses air to move water through the cage (airlifts) and therefore greatly increases the stocking density (see photos 3 and 4).

The key to get this system to work involves taking the solid waste (fish faeces and uneaten feed) and the dissolved waste (Ammonia) and lift the water into a nutrient trench that runs parallel to the trench where the fish are growing. In the nutrient trench, salt tolerant plants that can also tolerate waterlogging will be used to strip the excess nutrients (mainly nitrogen and phosphate) before the water flows back into the fish trench. The plants would be cropped regularly and then fed to sheep and cattle. Thus the farmer is not only growing marine fish (which due to overfishing world wide are becoming more valuable) but also growing fodder for stock.

Research

Photos 1 and 2. Above: excavating the trench, and below the trench ready for cages.

Photo 3 (above) fish cages in trenches and photo 4 (below) airlifts that allow for increased stocking densities.

6

The beauty of this system is that it is virtually drought proof. As can be seen from the photos the trench has been initially planted out with a salt sedge (Juncus krausii) but other species will be trialed such as Tall wheat grass (Thinopyrum ponticum) and Puccinellia (Puccinellia ciliata). It is hopeful that a new species being trialed by the University of WA, a highly palatable legume called Lotus tenuis, will also be tested at Goomalling. By passing the waste water through the nutrient trench the effluent water is scrubbed of the excess nitrogen and phosphorus before returning to the fish trench.

It is envisaged that the fish will take six months to get to market size (greater than 500 grams) thus two crops per year will be possible.

Besides being a great example of farm diversification the objectives of AFRD are to also produce a system that is farmer friendly. The system is designed with the busy schedule of growers in mind where there is little time available to look after fish. The Goomalling project has automatic feeders that would require the farmer to fill up the feeders once a week. The water quality is monitored by electronic probes so that if there is a power failure and the oxygen levels fall below a critical point, then a diesel generator kicks in and starts up a back up blower to aerate the water in the fish cages. The air and water temperature are also being monitored and these can be checked from the farmer’s home via a relay system connected to his telephone line and home computer. The trial will continue throughout the winter and the fish are expected to be harvested in late October.

For more information contact Tony Bart on mob. 0430514069 or email [email protected]

Research

Photo 5: Planting Juncus krausii in the nutrient trench.

Photo 6: Salt tolerant plants in the nutrient trench filter excess nitrogen and phosphorus.

Photo 7: The growing pond and nutrient trench.

Photo 8: Airlifted water entering the nutrient trench.

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Comparing salt across the country Need for a standardised system and terminology to classify saltland has been apparent for many years, and many different groups and geographical areas have their own local versions. A new Australiawide system has been proposed by Ed BarrettLennard from the Department of Agriculture and Food and colleagues at the Future Farm Industries CRC, which was presented to the International Salinity Forum in Adelaide in April.

Ed said that use of a standardised classification system would mean that any work on the salinity tolerance of potential fodder plants could be easily incorporated into the saltland capability assessment, regardless of where the research was undertaken. Results could also be readily extrapolated across States for use by extension workers and land managers seeking the most profitable and sustainable plant options.

Different terms are currently used in different States for the same levels of salinity as measured by Electrical Conductivity. For example, ECe levels of 816 dS/m (WE WOULD TEND TO USE 80160 MILLSIEMENS PER METRE BUT ED PREFERS DECISIEMENS. CONVERT IF YOU PREFER.) are often described as “very saline” in WA but “high” in South Australia. Then levels above 16 dS/m are called “extreme” in WA, “severe” in SA, while the same term “severe” can be used for 1435 dS/m in Victoria or more than 14 dS/m by the MurrayDarling Basin Commission. In 2005, MaryJane Rogers from Victoria proposed a standardised classification that ranged from nonsaline (with ECe values of 02 dS/m) to highly saline (more than

8 dS/m) but this level has little appeal to halophyte agronomists who deal with many soils with ECe greater than 16 dS/m, Ed noted.

Land with salinity around 20 dS/m would be capable of supporting halophytic grasses such as tall wheatgrass and puccinellia but other country at 60100 dS/m would only manage samphire, he said. These were all well off the Rogers scale which stopped at 8 dS/m.

Ed, with colleagues Sarita Jane Bennett and Tim Colmer, argues that there is need for an Australiawide soil salinity classification that is easy to use, compatible with State classifications where possible, and that links soil salinity to plant indicators. Their proposal is summarised in the table below. One of its great strengths is the mathematical simplicity: each class has double the ECe value (Electrical Conductivity of saturation extract) of the one before it. This means that the range for moderate salinity (48 dS/m) is twice that of low (24 dS/m) and half as much as high (816 dS/m).

Values are more complicated when EC1:5 (Electrical Conductivity in 1:5 extract) is used and need to be varied depending on soil texture. EC1:5 values are easy to measure and are widely used in the field.

Dr BarrettLennard would welcome any comment or debate about the merits of the proposed system. He can be contacted on telephone (08) 6488 1506 or email [email protected]

Table 1. Suggested Australian classification system for categorisation of soil salinity

EC1:5 range (based on conversions of George and Wren 1985) Suggested term

ECe

range (dS/m) For sands For loams For clays

Effect on plants

Non‐saline 0–2 0–0.14 0–0.18 0–0.25 Negligible

Low salinity 2–4 0.15–0.28 0.19–0.36 0.26–0.50 Decreased growth in sensitive crops such as beans

Moderate salinity 4–8 0.29–0.57 0.37–0.72 0.51–1.00 Decreased growth in most crops

High salinity 8–16 0.58–1.14 0.73–1.45 1.01–2.00 Only tolerant non‐halophytes can tolerate

Severe salinity 16–32 1.15–2.28 1.46–2.90 2.01–4.00 Decreased growth of most halophytes

Extreme salinity >32 >2.29 >2.91 >4.01 Some halophytes die, most have decreased growth

Research

8

Successful Pathways to Adoption workshop held at Tammin April 2 The recent Path to Adoption workshop at Tammin featured ‘headline’ technologies refined by CRC Salinity for whole farm and landscape water management in the eastern wheatbelt of WA, including lucerne phase farming, saltland pastures, and oil mallees. Day one of the workshop started with excellent presentations on the technologies from lead CRC researchers Perry Dolling, John Bartle and Ed BarrettLennard. Participants then learned more about the practical side of the technologies on four farms. Growers Simon York, Gavin Morgan, Rod Forsyth and Murray Clement talked about why they adopted the technologies, the challenges in adopting them, and whether they actually delivered anticipated benefits.

There was lively discussion and networking all day (and night!) amongst the diverse group of participants who had been invited to the workshop. Time will tell, but the Tammin workshop may have catalysed a regional advisers network for the eastern wheatbelt. Table group sessions inside on day two saw growers, CRC researchers and next users having indepth (and sometimes loud!) discussions about the merits of the technologies. They also put forward their ‘big ideas’ for what should happen next to increase adoption of the technologies.

The table groups were capably chaired by Sally Phelan, Project Manager with the Saltland Pastures Association, Dan Ferguson, Project Delivery Manager with Avon Catchment Council, and Tim Scanlon, Development Officer with DAFWA Merredin.‘Big ideas’ to come out of the Tammin workshop were: o promote lucerne to croppers as a tool to preserve cropping yields and land value, instead of promoting it as part of lucerne livestock systems to address waterlogging and salinity;

o promote saltbush as part of normal farm and landscape management, rather than something you do when land is no longer useful for anything else;

o establish regional partnerships between the Oil Mallee Association, State agencies and Shires, for coordinated oil mallee industry development.

More specifically for Saltland Pastures, workshop participants agreed that: Advantages of saltland pastures are that they: Are an option for 100% croppers in blocks and alleys for agistment or sheep trading; free up better quality land for cereals and create more efficient use of stubbles; allow different management of different classes of sheep; provide more resilience to climate change; provide Vitamin E, especially in northern areas; are fully tax deductible and increase the capital value of land asset; can knock down woody Old Man Saltbush (OMS) with rollers – it will reshoot; take advantage of sub surface irrigation; are productive with/without understorey; proper fit depends on design taking into account water, fences, cropland, saltland. Drivers for adoption of saltland pastures are: Favourable economics (on moderately saltaffected land); fear of lost production and reduced aesthetics; local NRM people.

Barriers to adoption of saltland pastures are: Unfavourable economics (on severely saltaffected land); high grain prices (even B class land can yield 6 bags or 1 tonne/ha of wheat); need to be more flexible in applying our recipes; not being at crop updates; not sure where to go for advice; lack of NRM advisers with skills, knowledge and confidence; lack of education and training opportunities for NRMOs; high staff turnover amongst NRMOs and agribusiness advisers; supply of seed/seedlings; postplanting management; lack of farmer measurement they tend to be reactive, eg only acting after observing scalds (when its too late to put more productive options in).

Several members of the FFI CRC Adoption & Commercialisation Consultative Panel also participated in the workshop. Representatives of Qualdata, which is monitoring and evaluating the impact of the CRC’s adoption and commercialisation activities, also attended. The workshop was organised by John Powell, FFI CRC Adoption Manager, with local onground support from John Borger, DAFWA Northam, and Glenice Batchelor, Project Manager of the Catchment Demonstration Initiative at Doodlakine/Kellerberrin and SPA Chairperson. For further information contact John Powell (02) 6226 5298 [email protected]

CRC Update

Grower Gavin Morgan used 2m deep soil pits to demonstrate the effect of lucerne in preserving his future grain yields. Gavin’s site at Kellerberrin is part of the Catchment Demonstration Initiative in the Avon region.

Dan Mudford from North Central CMA in Victoria makes a point during a table group session on day 2. North Central CMA is a Partner in the FFI CRC.

9

Is there a place for saltbush in an all‐cropping situation? Michael Lloyd, ‘Bundilla’, Lake Grace

High grain prices and recent dry seasons have seen some growers moving away from livestock to 100% cropping. This begs the question of whether saltbush can play a role in a total cropping system, or whether other salinity management options would be more beneficial. Lake Grace farmer and saltbush champion Michael Lloyd takes a look at the pros and cons of saltbush for the 100% cropper.

This question was asked recently at a CRC workshop, and the initial response was to talk about the possibility of using saltbush mixed with stubbles for agistment. It is true that there may be an opportunity to use saltbush and stubbles for agistment on some farms, but in many situations where the farmer has decided to go out of stock, the stock infrastructure may have deteriorated to such a degree that agistment is not viable. In addition to this, some farmers see more value in the stubble being retained as mulch and they regard the returns from agistment as being pretty minor.

So it does beg the question above – is there a place for saltbush on a nonstock farm? To answer this, perhaps we should first look at the role of saltbush in the farming system and in particular, its current role in a stock or mixedfarm enterprise.

In the past, saltbush has been seen as a good fodder source and terms like “living haystack” have often been used. In addition to this, saltbush was seen as the main fodder source, with the understorey of grass and clovers, hay or stubble as the supplement to mitigate the high salt levels and provide energy to balance the protein.

With observations over the last few years, many of us are now seeing saltbush in a different light. At densities of up to 1000 plants per hectare, we are experiencing watertable drawdown of between one and two metres, which in turn has seen a massive increase in the amount of annual clovers and grasses growing, right up to and in amongst the saltbush. The combination of the energy in the annuals and the protein in the saltbush, together with the high levels of Vitamin E in the saltbush, make for an almost perfect fodder for stock. So maybe the saltbush’s primary purpose is not to provide the “base” fodder, but to lower the watertable enough to allow for large quantities of annual understorey to be grown for energy. Perhaps in this case, the saltbush becomes the supplement!

But what about the all cropping farm with no stock? Principally, it is the ability of the saltbush to use groundwater and lower the watertable that will benefit the cropping system.

With rising watertables a feature of our wheatbelt, particularly in the broad valley floors, there is a desperate need to introduce more perennials into the farming systems, including cropping systems. Generally people have looked to phase farming with lucerne, or alley farming with eucalypts, often oil mallees, to be that perennial.

Let’s see how these options stack up.

Phase Farming ‐ Lucerne Generally, when lucerne is introduced into a phased farming cropping system, it is with 3 years of lucerne followed by 4 years of cropping, or a similar rotation. This means that in any one year, there would be 43% of the area in lucerne and 57% in crop – not the most attractive scenario for someone with no stock! In addition to this, the phase system increases the risks in a variable or changing climate. With no perennials in a cropping paddock for 4 years, high rainfall years or even high rainfall events increase the chance of rising watertables with no perennial to soak up the excess. Also, in years of low rainfall in the crop year following lucerne, there is the risk of lower crop yields due to the drying effect of the lucerne in the perennial phase and lower rainfall in that crop year. While there is a place for lucerne in a mixed farming system as opposed to all cropping, there is also an increased risk in the event of climate change and severe climate conditions – both wet and dry.

Information

Phase farming with lucerne increases water use

10

Alley Farming ‐ Oil Mallees and other eucalypts Another option of introducing perennials into a cropping system is to use alley farming – in this case oil mallees or other eucalypts. While there may be some argument about the amount of water use by eucalypts in nonsaline situations, when the concentration of salt in the groundwater rises to 20 dS/m (about 35% of sea water), their growth and therefore water use will decline. As well, eucalypts are renowned for “robbing” soil adjacent to the rows of nutrients and water, leaving crops near the shrubs stunted or withered or the soil bare ask any farmer with a solitary salmon gum in the centre of a paddock! Of course, this will vary according to species. Eucalyptus sargentii (Salt River gum) can have bare areas up to 3m either side of the row of trees in the alley. In spite of this, alleys of eucalypts may provide watertable control (provided the groundwater is not too saline), will use summer rainfall and provide erosion control.

Alley Farming – Saltbush As with trees and other shrubs in alleys, saltbush will use summer rainfall and provide erosion control. It will also lower watertables, even where saline groundwater is present, although its growth may slow in the presence of extremely highly saline groundwater. However, it does have one big benefit over eucalypts – the annuals will

grow right up to the base of the saltbush. In fact, there is some anecdotal evidence that the grasses grow better in amongst the saltbush, and certainly seem to benefit from the shelter of the alley system.

So to ask the question again – Is there a place for saltbush in an allcropping system?

When the evidence is considered, the answer must be YES!

Alleys of saltbush will help with watertable control, especially at moderate levels of groundwater salinity. Some farmers have expressed concern about losing up to 20% of their cropping land by planting alleys. If saltbush is used for the perennial in the alley system and it is introduced before the rising saline groundwater is affecting crop production, it will provide longterm protection against salinity, protection against wind and water erosion and protection from the damaging effects of strong winds. Crops will be able to be grown right up to the saltbush.

But then the next question that must be asked of a farmer with land at risk from rising saline groundwater is:

“Do you want to crop 100% of this paddock for the next 5 to 10 years before it becomes saline, or do you want to crop 80% of it for the next 50 or so years?”

Information

Alleys of oil mallees with cropping in the inter‐ row

Alleys of saltbush with legume understorey

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1010

Pond aquaponics: new pathways to sustainable integrated aquaculture and agricultureEdoardo Pantanella

Rising environmental concerns and growing demand for different uses of production inputs set new challenges for aquaculture d e v e l o p m e n t . I n c r e a s e d p r o d u c t i v i t y w i t h r e d u c e d ecological impact, integration between production systems and reduced use of chemicals are just some of the leading principles that more sustainable fish production needs to follow.

In developed countries concerns about pollution issues have raised interest in aquaponics as a valid option to get rid of

aquaculture wastes through the production of high value vegetables (Rakocy et al, 2006; Diver, 2006). However in developing countries this technology, run mainly in recirculation systems, is not often applicable to local aquaculture systems.

In Southeast Asia freshwater fish production is mostly carried out in ponds where constant fertilisation occurs to sustain phytoplankton and zooplankton growth. The presence of green algae and micro organisms helps maintain adequate oxygen levels and to sustain in-pond feed availability. However, if on one hand green algae help in enriching pond water on the other hand they prevent plant nutrient build up.

Research in Thailand implied the use of alternative strategies for pond fertilisation

that allow plants to take up nutrients both from water and from supplied growing media.

The floating garden conceptA key idea for developing such systems arose by studying the Bangladeshi “Dhats”, rafts made with floating water weeds, mostly water hyacinth (Eichhornia crassipes) (Practical Action, 2007). This indigenous growing system is nowadays rediscovered by farmers living in flood prone areas and allows for vegetable production all year round. Their use is pretty simple since weeds are piled together in water bodies. When the mass of vegetables reaches a critical volume they can physically sustain vegetable growth and supply nutrients through biomass decay.

Trials carried out in Nam Sai Farms, Thailand used manure, composted water weeds or rice husk ash as growing media, which were left floating on water in boxes or trays. No external energy or mechanical inputs (pumps or filters) were used. Plants were left to grow in a catfish (Clarias sp) pond, in tilapia (Oreochromis sp) ponds and a river with different growing media. Assessments determined yields under different nutrient levels supplied both by water and by growing media. Comparisons were also carried out against traditional production methods such as hydroponics (raft system) and soil-based agriculture under high fertilisation rates.

Very interesting yields have been noticed in catfish ponds where plants can simply take advantage of high nitrogen levels in the water, even at low dissolved oxygen levels. On the other hand wherever water nutrients were the limiting factor, nutrient supplement from growing media allowed results close to soil-based growing systems.

Fig. 1 Floating garden made with water hyacinth

11Aquaculture News 34 / May 2008 11

Advantages in integrated productionHigher revenues can be achieved by farmers who can increase farm productivity and differentiate production with limited investment. Free availability of water weeds guarantees cheap supplies and keeps channels clear of clogging vegetation, thus providing an important environmental service. Decaying organic material can help fertilise ponds and at the same time provide a plant growing environment less prone to diseases and to soil pests. Reduction of chemical inputs allows farmers to get premium prices from soilless (hydroponic) or organic vegetables in a market quite sensitive to pesticide use in agriculture. Surveys carried out in the Bangkok area suggest that nearly all the vegetables sold in supermarkets (conventional, hydroponic or organic), show some degree of certification and traceability. In addition hydroponic and organic product prices are 100-600% higher than those of conventional agriculture (from

0.75-1.1 €/kg for conventional up to 4-7.6 €/kg for hydroponics and organic lettuce).

Future perspectivesSimplicity in design and management with almost no energy and low equipment costs makes these systems an interesting solution wherever land availability, flooding, productivity and ecological footprint are an issue. In addition the use of water weeds as a resource can indeed increase livelihoods opportunities in all those areas affected worldwide.

Further research needs to address the nutrient dynamics of different growing media and to optimise system design and nutritional requirement of vegetables in those water bodies with limited dissolved nutrients. The possibilities of this integrated system are quite high and can provide sensitive benefits to smallholders as well as big aquaculture enterprises.

Fig. 2 Trials in catfish farm

Fig. 3 Water weeds in tropical areas can easily double their biomass in just a few days

Fig. 4 Growth comparison for romaine lettuce. A on raft made with water hyacinth; B on ash pots in a catfish farm; C on ash with zero nutrients (control); D on soil with full use of fertilizer

The potential of these systems is however not fully acknowledged and interdisciplinary links and research can undoubtedly address many of the issues that are still unattended.

ReferencesDiver S, 2006. Aquaponics—Integration of Hydroponics with Aquaculture (Internet). ATTRA - National Sustainable Agriculture Information Service. Available from: <http://attra.ncat.org/attra-pub/PDF/aquaponic.pdf> (accessed on 02/4/2008)

Practical Action (2007) Floating Gardens in Bangladesh (Internet). The Schumacher Centre for Technology & Development. Available from: <http://practicalaction.org/practicalanswers/product_info.php?cPath=24&products_id=201> (accessed on 02/4/2008)

Rakocy, J.E., Masser, M.P. and Losordo, T.M. (2006) Recirculating Aquaculture Tank Production Systems: Aquaponics-Integrating Fish and Plant Culture (Internet) SRAC Publication No. 454 (revision November 2006) Department of Agriculture, USA. Available from: < http://srac.tamu.edu/tmppdfs/1251841-srac454.pdf?cfid=1251841&cftoken=a3bfa0221a4d437c-1867122a-7e93-35cb-88db9c0db730c1de&jsessionid=8e304aae606019523c1d > (accessed on 03/4/2008)

24 summer 2008 EDIBLE NUTMEG

Class was about to begin at the Donald F. Harris Sr. Agri-Science & Technology Center at Bloomfield High School. Joe Rodrigues, the environmental science teach-er—not one to suffer fools lightly—stood in the front hall, eyeing each student as they burst through the door. A latecomer sauntered in and Joe nabbed him. “Yo! I want to talk to you.” The kid tried to show Joe the Red Cross bandage he received after giving blood—an excuse, he thought to get out of class. Joe was having none of it. “In this class today, you’re going to keep your butt in your chair. No fooling around.” The kid faked a shocked look. “But Mr. Rodrigues, I just gave blood, doesn’t that get me off the hook?” Joe smirked, “Of course not.” Tough love.

Lanky and well dressed, replete with spotless, well-shined shoes and a signature bow tie, Joe has a take-no-prisoners attitude that his students seem to respect. With almost 100 pupils taking courses at the center, he doesn’t have a lot of time for fooling around. Joe and his colleagues at the Agri-Science Center work with freshmen to se-niors, not only from Bloomfield but also from Windsor, East Granby, and Hartford. Harris is one of 19 agricultural education centers in Connecticut where students come to learn how to grow food.

“Kale, tomatoes, basil, herbs, lettuce, peppers, shallots,” Joe says as he shows me around the freshly planted garden out back. “We grow it all here.” His infectious enthusiasm for this program spreads to the kids—but don’t tell them that. If you visit their on-site green-house in late winter, you will find the students planting seedlings in tiny pots, and some will gripe about the workload. Teenagers are fickle by nature, eager to plant one minute, quickly bored the next. “Come on!” Joe will chide them. “We haven’t got all day,” he says to one student playing with her iPod. But even with their can’t-be-both-ered posing, the kids will tell you how cool they think the program is. One teenager told an NBC30 interviewer: “It’s actually exciting, you know, to see something you grew in first period that’s eaten in third period for lunch.”

The students are secretly proud of the fact that in a month’s time, seedlings they planted in January end up as lovely arugula plants which are then harvested by the culinary arts students, who also learn, in a class taught by Chef Paul Waszkelewicz, how to cook with the slightly spicy salad green and other greenhouse specialties. More of the produce ends up in the cafeteria kitchen, prepared by the staff for all the high school students. The basil they grow becomes topping on pizzas; the habanero pep-pers are turned into a sauce for the pork sandwiches.

Jaunice Edwards, who joined the program at its in-

ception in 1997, when all the agriculture education was taught in one room, is now the director of the Agri-Science Center. She is in charge of their hydroponic, floral design, and aquaculture programs while Mary LeBlond, the animal science teacher, handles the lop-eared rabbits and free-range chickens. Starting in the fall they will have up to 30 layers, mostly Rhode Island Reds and Barred Rocks, and will be selling eggs to the public.

In the early years they had trouble just giving away the food they grew. “We weren’t really doing much with all this food we were pro-ducing,” Jaunice admitted, telling me that at one point they even discontinued their aquaponics program. It’s just in the past couple of years that the Center has extended training to practical application thanks to the arrival of the Local Food Dude, or rather, Timothy Cipriano. Coming on board in 2005 as food service director, Tim oversees six schools (K–12) with a total of 2,400 kids, who get served a whopping 1,800 meals per day in six cafeterias with two full-service kitchens. What seems overwhelming to a home cook is routine for a food service professional. However, instead of sourcing entirely from one or two distributors, Tim orchestrates many players to improve the quality of food on students’ plates. He has created the much ad-mired Bloomfield Schools Farm-to-School Program [BSF2S], sourc-ing local foods for cafeteria meals and decreasing the time-tested use of a can opener and three-quart cans of industrial tomato sauce. This

FARM-TO-SCHOOL

ONE FISH, TWO FISH…Growing lunch with aquaponics

By MeliSSa Waldron lehner

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EDIBLE NUTMEG summer 2008 25

ongoing collaboration between the Agri-Science, Culinary Arts, and Foodservice departments has become known in the culinary-school world as a cutting-edge education program and is now hotly sought after by students. Many who graduate have gone on to culinary schools, or now work for local food projects like the Connecticut Agricultural Experiment Station and the Hartford Food System. And far fewer students bring their own lunches.

Out of all the agricultural initiatives, the resuscitated aquaponics program is the most avant-garde, and has thrived with Tim’s support. Aquaponics is the combination of aquaculture and hydroponics, or simply stated, a place where you grow plants and fish together in one big tank. It is considered to be a very sustainable form of farming since the fish waste, formerly discarded, now provides a food source for the growing plants while the plants provide a natural water filter for the fish.

Jaunice took me on a tour of the aquaponics room, which is part of the greenhouse facilities. There are three 250-gallon tanks plus one that holds 700 gallons. The big fat tank has lettuces and tomatoes growing on top, the smaller ones have 45–50 basil plants floating on top in Styrofoam beds, each tucked into a hole that allows the roots to feed on the fish waste. “The plants grow really well in water,” says Jaunice. “In fact, they grow twice as fast as they do in soil. Growing them in soil actually takes a lot more work.”

And underneath the greenery are schools of tilapia and catfish swimming about. One 250-gallon tank can hold 100 pounds of fish while the 700-gallon tank can hold 500 pounds. That’s a lot of fish, enough to feed armies of students. Last semester was a test run, but Jaunice feels that by the fall, the cafeteria menu will be featuring pan-fried catfish and tilapia quite often. The few fish they had this spring ended up in a fish fry at the school’s first farm-ers’ market last May. Cheneil Carnegie, a junior who is on her way to chef stardom, was one of the students cooking the fish that day. “My dad was a chef so it’s in the family. And from here I plan on going to Johnson and Wales to become a chef too.” She stopped and thought about it for a second. “An executive chef, that is.” Squirting more lemon onto the fish in the pan she looked at me and beamed. •

resourCes

Bloomfield Schools Farm-to-School Programwww.blmfld.org/farmtoschool

Donald F. Harris Sr. Agri-Science and Technology Centerwww.blmfld.org/agriscience

Local Food Dudewww.localfooddude.com

National Sustainable Agriculture Information Servicewww.attra.ncat.org/attra-pub/aquaponic.html

Connecticut Sea Grantwww.seagrant.uconn.edu/aquaguide/

Auburn University: Department of Fisheries and Allied Aquacultureswww.ag.auburn.edu/fish/

Documents

Small Articles and Information - Aquaponics