An aquaponics life cycle assessment

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An aquaponics life cycle assessment evaluating an innovative method for growing local fish and lettuce
Evaluating an innovative method for growing local fish and lettuce
Hollmann, Rebecca Elizabeth ( author )
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Aquaculture ( lcsh )
Fisheries ( lcsh )
Lettuce ( lcsh )
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )


In most states, only one to two percent of the food consumed comes from a source within one hundred miles. The transition of food production to an industrialized global system has increased the use of artificial fertilizers, pesticides, and fossil-fuels, which negatively affects the environment, human health, and local economies. Actively promoting, optimizing, and investing in local food systems can reduce society’s reliance on industrial food production. Local food systems will become increasingly important due to the projected decreases in food production from climate change, the increasing demand for food due to population growth, and the nutrient pollution from current agriculture methods. Local food production benefits include increased food security and sovereignty, improving local economies, supplementary nutrition, preservation of genetic diversity, and fostering communities. The current study is a life cycle assessment (LCA) of a local food production system known as aquaponics. Aquaponics combines aquaculture and hydroponics in a recirculating engineered ecosystem using minimal resources and generating negligible waste. This research evaluated the global warming potential (GWP), energy use (EU), and water dependency (WD) of a local aquaponics system. These values where then compared with literature studies of traditional agriculture, hydroponics, and aquaculture. The LCA found that aquaponics yielded 22.02 kg wet mass (WM)/m2 of lettuce production, or 560% higher than traditional soil crop yield of 3.90 kg WM/m2 where hydroponics had the highest yield of 41.00 kg (WM)/m2. Aquaponics had a lower WD than traditional agriculture, 0.06 m3/kg to 0.25 m3/kg respectively, but a higher WD than hydroponics at 0.02 m3/kg. The EU for aquaponics was 10.58 mJ/kg, nine times lower than hydroponics at 90.00 mJ/kg of lettuce, but higher than traditional agriculture records of 1.10 mJ/kg. Aquaponics had a GWP of 8.50 kg CO2 equivalency per kilogram of fish production, and 4.45 kg CO2 e/kg for lettuce production. All other aquaculture systems had a higher EU and WD than aquaponics. Understanding the costs and benefits to aquaponics may lead to better system management and long-term decisions on the sustainability of aquaponics as an agricultural system.</DISS_para>
Thesis (M.S...)--University of Colorado Denver
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by Rebecca Elizabeth Hollman.

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REBECCA ELIZABETH HOLLMANN B.A., University of Denver, 2013
A thesis submitted to the Faculty of the Graduate School of the University of Colorado Denver in partial fulfillment of the requirements for the degree of Master of Science Integrative Biology


This thesis for the Master of Science degree by Rebecca Elizabeth Hollmann Has been approved by the Department of Integrative Biology for
Greg Cronin, Co-Chair John Brett, Co-Chair
Laurel Hartley

Hollmann, Rebecca Elizabeth (M.S., Integrative Biology)
An Aquaponics Life Cycle Assessment: Evaluating an Innovative Method for Growing Local Produce and Protein
Thesis directed by Associate Professor Greg Cronin, and Associate Professor John Brett
In most states, only one to two percent of the food consumed comes from a source within one hundred miles. The transition of food production to an industrialized global system has increased the use of artificial fertilizers, pesticides, and fossil-fuels, which negatively affects the environment, human health, and local economies. Actively promoting, optimizing, and investing in local food systems can reduce societys reliance on industrial food production. Local food systems will become increasingly important due to the projected decreases in food production from climate change, the increasing demand for food due to population growth, and the nutrient pollution from current agriculture methods. Local food production benefits include increased food security and sovereignty, improving local economies, supplementary nutrition, preservation of genetic diversity, and fostering communities. The current study is a life cycle assessment (LCA) of a local food production system known as aquaponics. Aquaponics combines aquaculture and hydroponics in a recirculating engineered ecosystem using minimal resources and generating negligible waste. This research evaluated the global warming potential (GWP), energy use (EU), and water dependency (WD) of a local aquaponics system. These values where then compared with literature studies of traditional agriculture, hydroponics, and aquaculture. The LCA found that aquaponics yielded 22.02 kg wet mass (WM)/m2 of lettuce production, or 560% higher than traditional soil crop yield of 3.90 kg WM/m2 where hydroponics had the highest yield of 41.00 kg (WM)/m2. Aquaponics had a lower WD than traditional agriculture, 0.06 m3/kg to 0.25 m3/kg

respectively, but a higher WD than hydroponics at 0.02 m3/kg. The EU for aquaponics was 10.58 mJ/kg, nine times lower than hydroponics at 90.00 mJ/kg of lettuce, but higher than traditional agriculture records of 1.10 mJ/kg. Aquaponics had a GWP of 8.50 kg CO2 equivalency per kilogram of fish production, and 4.45 kg CO2 e/kg for lettuce production. All other aquaculture systems had a higher EU and WD than aquaponics. Understanding the costs and benefits to aquaponics may lead to better system management and long-term decisions on the sustainability of aquaponics as an agricultural system.
The form and content of this abstract are approved. I recommend its publication.
Approved: Greg Cronin Approved: John Brett

This thesis would not have been possible without the collaboration and contributions of Tawnya and JD Sawyer, owners and CEOs of Flourish Farms and Colorado Aquaponics. Their meticulous attention to detail, record keeping, allowing me access to their database, and answering my many questions is the foundation of this research. I also would like to specifically thank Marielle DOnofrio for answering many questions for me, finding specific metrics and helping to gather data. My advisors at University of Colorado Denver, Dr. Greg Cronin and Dr. John Brett, have been endlessly helpful in supporting my academic development, mentoring me and guiding me through this thesis. I would also like to thank my committee members, Dr. Alan Vajda and Dr. Laurel Hartley, for providing feedback and support on this thesis. Thank you to Tamara Chernomordik for assistance with the GaBi V5.0 life cycle assessment software, and guidance on how to analyze the data on this software. Also, an immense thank you to Stephen Fisher, PhD, who assisted me in the theoretical frameset of my paper and understanding the Life Cycle Assessment method.

ALTERNATIVE FOOD SYSTEM............................................... 1
1.1 Introduction.................................................... 1
1.1.1 Inner workings of aquaponics............................... 1
1.1.2 History of aquaponics...................................... 3
1.1.3 Aquaponic system types..................................... 5
1.1.4 Comparison System.......................................... 8
Hydroponics................................................... 8
Aquaculture................................................... 9
Conventional Agriculture...................................... 9
1.1.5 Aquaponic production......................................... 10
1.1.6 Aquaponic system potential................................... 11
1.2 The importance of alternative food systems........................ 14
1.2.1 Climate change threatening food security................... 14
1.2.2 The growing population: water and food demand.............. 14
1.3 Rel evant b ackground............................................. 16
1.3.1 Flourish Farms............................................... 16
1.3.2 Elyria Swansea neighborhood.................................. 19
1.4 Life cycle assessment practices................................... 23
1.4.1 Goal and scope description................................... 25
1.4.2 Inventory analysis description............................... 27
1.4.3 Impact assessment description................................ 27

1.4.4 Interpretation stage description............................ 28
II. AQUAPONICS LIFE CYCLE ASSESSMENT..................................... 29
2.1 Introduction..................................................... 29
2.1.1 Research objectives......................................... 30
2.1.2 Study site.................................................. 30
2.2 Methodol ogy..................................................... 32
2.2.1 Goal and scope.............................................. 31
2.2.2 Life cycle inventory........................................ 36
2.2.3 Life cycle impact assessment................................ 43
Allocation..................................................... 44
Total resource use............................................. 44
Conversion..................................................... 44
2.3 Results.......................................................... 45
2.4 Discussion....................................................... 51
2.4.1 Impact assessment........................................... 51
2.5 Conclusion....................................................... 58
REFERENCES............................................................... 59
A. Flourish Farms delivery locations............................... 66
B. Flourish Farms produce production............................... 67
C. Flourish Farms integrated pest management use in 2014........ 69

1. Nutrient waste in a levee-style catfish pond 13
2. Pre-farm, on-farm and post-farm inclusions and exclusions in the LCA 34
3. Life cycle inventory of Flourish Farms 35
4. Electrical operational equipment at Flourish Farms 38
5. Necessary infrastructure in Flourish Farms aquaponic system 41
6. The total global warming potential (kg CO2 e), energy use (mJ) and 47
water dependency (m3) for Flourish Farm lettuce and tilapia and hybrid
striped bass per kilogram in 2014.
7. Comparison of annual land use, water dependency, and energy use in 49
aquaponics, hydroponics and traditional agriculture for lettuce
8. Comparison of global warming potential, energy use, and water 50
dependency of various aquaculture systems with values in terms of one
kg produced.

1. The recirculating principles of the aquaponics life cycle 3
2. The University of the Virgin Islands deep water culture (DWC) 5
aquaponic facility.
3. Media based aquaponic system 6
4. Deep water culture root system 7
5. Nutrient film technology (NFT) aquaponic system 8
6. Layout of FI ouri sh F arm s 17
7. Flourish Farms DWC and main fish tank 18
8. Boundaries of Denver, Colorado zip code 80216 20
9. Major Toxic Releasing Inventory (TRI) facilities and super fund sites in 21
or next to zip code 80216
10. Denver County food desert 22
11. Phases of a life cycle assessment 25
12. System boundary for the Flourish Farm LCA 33
13. Life cycle assessment process flow for fish 36
14. Life cycle assessment process flow for lettuce 37
15. Skrettings Pond LE fish feed components 39
16. The GrowHaus delivery route 40
17. Global warming potential of fish production at Flourish Farms 46
18. Global warming potential of lettuce production at Flourish Farms 47
19. Distribution of global warming potential kg of CO2 e/ kg of production 48
within Flourish Farms.

co2 Carbon Dioxide
DM Dry Mass
DWC Deep-Water Culture
EPA Environmental Protection Agency
EU Electricity Use
GHG Greenhouse Gas
GWP Global Warming Potential
HSB Hybrid-striped bass
ILCD International Reference Life Cycle Data Systems
IOS International Organization for Standardization
IPCC Intergovernmental Panel on Climate Change
IPM Integrated Pest Management
LCA Life Cycle Assessment
LCIA Life Cycle Inventory Analysis
NFT Nutrient Film Technology
TRI Toxic Releasing Inventory
USDA United States Department of Agriculture
WD Water Dependence
WM Wet Mass

1.1 Introduction
1.1.1 Inner workings of aquaponics
This research assesses efficiency and output of a commercial aquaponics system known as Flourish Farms in Denver, Colorado. The global food production system is projected to decline in crop output due to climate change (Nelson, 2009), and population growth will continue to exceed the carrying capacity of the planet (Barrett & Odum, 2000), which will lead to a greater percentage of the worlds population receiving inadequate nutrition on a daily basis. Current agricultural methods are a primary contributor to climate change and environmental degradation. If current agriculture is further invested in and expanded in order to meet the increasing demand, environmental collapse is expected (Edenhoger et al., 2014). Alternative food production systems, such as organic, hydroponics, aquaculture, urban gardening, and local food production offer a solution to steer away from the global food system, and towards healthier and more sustainable crop output while revitalizing the environment. Aquaponics is a promising system design to produce protein and vegetables using minimal resources and waste production. This technology is in the early stages of development worldwide with few commercial systems. Completing a Life Cycle Assessment (LCA) on one of the well founded commercial systems in Denver will elucidate the resource use, global warming potential and waste production of this aquaponics system.
Understanding the system value may lead to better system management, and long-term decisions on the viability of aquaponics as a potential for year-round local food production in temperate climates.

Aquaponic fanning is a promising technology for local, sustainable food production. Aquaponics combines aquaculture (e.g. aquatic animal farming) and hydroponics (e.g. soilless systems for crop production) in a recirculating engineered ecosystem to simultaneously produce vegetables and protein. Aquaponics systems have a high yield and can annually produce 41.5 kg/m3 of tilapia and 59.6kg/m2 of tomatoes in a 1.2m wide, 0.33m deep and 0.86m long tank with 4 plant plots (McMurtry et al., 1997). Aquaponic farms utilize the effluent from aquatic animals rich in ammonium by circulating it to nitrifying rhizobacteria to fertilize hydroponic vegetables. Nitrosomona species oxidize the toxic ammonia (NH3) into nitrite, and then Nitrospira bacteria convert nitrite (NO2-) into nitrate (NO3-), which is less harmful to the fish, but fertilizes the plants. The water, now cleansed of ammonia, nitrates, and other nutrients after flowing through the bacteria matrix and root system, circulates back to the aquaculture subsystem (McMurty et al., 1997) (Fig 1.).

Filh eXOVte lOQSte product
Nftroiomenas sp. eommrls NH3
It) NO,
Dflrttnww eat solid parts
Vegetables atmirh NOj
to NO)
Figure 1. The recirculating principles of the aquaponics life cycle. The fish excrete waste products which are turned into nitrates from bacteria species such as Nistrospira sp. The root system is then able to absorb these nutrients, and quickly grow into a harvestable product. The fish are then supplied with clean water and are another harvestable product within time (Engle, 2013).
1.1.2 History of Aquaponic
Although the term aquaponics was coined in the 1970s, the science of aquaponics developed long ago. One of the earliest was the Aztec agricultural islands known as chinampas that would float on top of shallow lakes about 1,000 years ago (Crossley, 2004). Aztecs would fertilize the islands with nutrient rich mud from nearby canals. Additionally, in South China, Thailand and Indonesia grew fish in rice fields approximately 1,500 years ago

(Coche, 1967). This polyculture practice still exists today as hundreds of thousands of hectares of rice fields are stocked with fish (Coche, 1967).
Development of contemporary aquaponic systems is practiced in warm and temperate climates with many variations in system construction and cultivated species (Bainbridge, 2012). Modern aquaponics was first influenced by researchers studying recirculating aquaculture systems who were looking for solutions to eliminate accumulations of nitrogen (Love et al., 2014). One of the solutions researchers identified was to combine a soilless plant system into the aquaculture system as a way of withdrawing the nitrogen compounds out of the water. Present-day systems now rely on many hydroponic growing methods, such as use of a greenhouse, and similar growing technologies.
One of the major revolutions to the aquaponics industry was the work of Dr. James Rakocy, known colloquially as the Father of Aquaponics. He began further investigation of aquaponics systems while working on his PhD at Auburn University, graduating with a degree in aquaculture in 1980. He then developed an aquaponics facility at the University of the Virgin Islands (UVI). The system started small, but continued to expand into a commercial system which contains six hydroponic tanks with a growing area of 2,303 ft2 and four fish rearing tanks containing 7798 liters of water each. In 1999 Dr. Rakocy started a training program with students from all over the Unites States and territories. The system has become an important tool in training students and educators about aquaponics all over the world, and has proven to be successful in producing high quantities of fish and vegetables (Rakocy, 2012). Dr. Rakocy and Dr. Lennard now teach a commercial aquaponics workshop at UVI two times a year, which has been instrumental for the development of large scale systems worldwide (Rakocy, 2012; Fig. 2).

Figure 2. The University of the Virgin Islands DWC aquaponic facility. UVI has one of the best established and deep water culture aquaponic systems where they offer intensive training course (Rakocy, 2012).
1.1.3 Aquaponic system types
There are three main types of aquaponic system constructions: media-based growing, deep-water culture (DWC), and nutrient film technology (NFT). At minimum, a system will have some form of a tank containing aquatic species, grow beds, and a pump. Most systems contain a solids removal system; however, in media-based systems scuds and/or worms can be added as an effective solids removal mechanism. Within the media-based growing there are several different designs that can be put into place. There are basic flood and drain systems, designs with sump tanks, constant height one pump systems, and even systems using barrels (Bernstein, 2011; Lennard & Leonard, 2006). There are pros and cons to adding sump tanks to a system. Sump tanks are second tanks kept without fish, where water will continuously drain from the grow beds before recirculation. Designs without a sump are typically much more simple and easy to construct, however the changing water levels can add stress to the fish. Designs with a sump tank are more difficult to construct, but will keep

the water in the fish tank at a continuous level, which is ideal for the fish (Bernstein, 2011; Fig. 3).
Fish lank Sump Plant t^pwing area
Figure 3. Media based aquaponic system with sump tank. In farms using media, the water
will flood and drain the system. Some advantages for the media based solution are growing
more root intensive crops, solid entrapment, and some systems use detrivores in the media as
well (Lovatelli, 2015).
The seeds in media based systems can be planted directly into the media, or transplanted from nurseries. The media and root matrix is an efficient solids filter, and no other removal system is needed. Media based systems also provide ideal growth environments for the necessary bacteria. Another advantage to a media based system is this design allows the greatest flexibility for what crops can be grown.
DWC systems use water filled beds with floating rafts which support the shoots above the waterline, as the roots hang into the water. The roots hang into the water directly and the bacteria can usually grow onto these extensive root systems without further assistance (Fig.

4). In some farms, the bacterial will cultivate within the solids removal and dentrification tanks as well.
Figure 4. Deep water culture root system. In DWC systems, the roots hang loose into the water culture on floating rafts (
DWC aquaponic farms are more limited in what they can grow, and do require further solids filtration. However, these systems are typically used in commercial aquaponics facilities as they are relatively inexpensive to set up compared to other system types, and the crops are considerably more easy to harvest than in a media based system (Bernstein, 2011).
The last type of system, NFT, uses condensed channels into which nursery plants are transplanted, where a more concentrated stream of water flows through the root systems (Fig. 5). These systems look characteristically more like hydroponic systems. They offer many of the same advantages and disadvantages of DWC systems, in that the crops are easy to

harvest, but the varieties that can be successfully grown are limited (Bernstein, 2011). This system is primarily used for leafy greens and herbs, as other plants develop extensive root systems that can easily block the channels (St. Charles, 2013).
Figure 5. Nutrient film technology aquaponic system. NFT systems are one of the most common growing practices for hydroponic systems, and the technique has carried over into aquaponics (Lovatelli, 2015).
1.1.4 Comparison Systems
Hydroponics. The word hydroponics is derived from the Greek roots of hydro and ponos, meaning working water. The history of hydroponics dates back to 1929 with Dr. William Gerich from the University of California (Love et al., 2014). In essence, hydroponic farming is the science of growing plants without the use of soil, in a liquid culture (Wignaijah, 1995). In hydroponic systems, nutrient solutions, mainly chemical salts, are added to the culture that contains all the essential elements needed by the plant for its normal growth and development. Like aquaponics, hydroponics can be developed with several different designs, including NFT as one of the most popular techniques for producing leafy greens. However, media based options are still used to support a larger variety of vegetables. Many hydroponic systems are operated in controlled environment facilities in order to

increase the yield of the crops. Additionally, since the roots can easily obtain the necessary nutrients in the synthetic liquid cultures, the yield is often much higher than conventional agriculture (Love et al., 2014). Hydroponics also recirculates the water in order to more sustainably nurture and support plant production.
Aquaculture. Aquaculture is the breeding, rearing and harvesting of plants and animals within a water environment, which can range from ponds, rivers, lakes and the ocean. Aquaculture has a long history of practice, dating back to 2,500 B.C. in China, with the cultivation of common carp (Cyprinus carpid) (Rabanal, 1988). Near 500 B.C. Fan Lai wrote a monograph names The Classic of Fish Culture, which is the first known description of aquaculture practices. Aquaculture can also be known as aquafarming, which implies intervention in the natural rearing process in order to enhance production. These practices can range from stocking, feeding, and protection from predators (FAO, 2011). Today with the decline of wild fish populations, aquaculture is a massive industry with over one half of consumed fish products supplied by aquaculture facilities (Stanford University, 2009).
Conventional Agriculture. The modem industrial agricultural practice has historically been defined as growing crops with soil, without cover, and treating the crops with irrigation, nutrients, pesticides and herbicides (Barbosa et al., 2015). These traditional agricultural techniques became popularized in the 20th century, which was known as the Green Revolution (Hazell, 2009). With these technologies, conventional agriculture produces great yields, but also has intensive resource requirements. Conventional agriculture is often juxtaposed to organic farming, which does not permit the use of synthetic fertilizers, pesticides, genetically modified organisms, or ionizing radiation or sewage sludge (USDA, 2016). These standards were developed in the late 19th century in central Europe and Asia.

1.1.4 Aquaponic Production
Aquaponics technologies have records of successfully raising many different types of fish including: several varieties and hybrids of tilapia such as red tilapia (Oreochromis spp) and Nile tilapia (Ocheochromis niloticus), and many other species such as yellow perch {Perea flavescens), catfish {Ictaluruspunctatus), striped bass (Morone saxatilis), rainbow trout {Oncorhynchus mykiss), Arctic char {Salvelinus a/pinus), barramundi {Lates calcarifer), Murray cod {Maccullochellapeeliipeelii), common and koi carp (Cyprinus spp), goldfish {Carassius auratus) and crustaceans such as red claw crayfish (Cherax quadricarinatus), Louisiana crayfish {Procambarus clarkii), and giant freshwater prawn (Macrobrachium rosenbergii) (Bainbridge, 2013).
There are over 60 species of plants successfully grown using aquaponics, and many more in home hobby systems (Bainbridge, 2013). Leafy crops, such as kale, romaine and bib lettuce, have typically been the most successful and can be grown in any of the above system designs. In order for these plants to grow, they must absorb carbon and oxygen from the air, and obtain water, macro and micro nutrients and light. In addition, plants require three primary macronutrients (nitrogen, phosphorus, and potassium), three secondary macronutrients (calcium, sulfur, and magnesium) and eight micronutrients (boron, chlorine, manganese, iron, zinc, copper, molybdenum and nickel) to grow (Barker & Pilbeam, 2007).
In aquaponics, all of the macronutrients are obtained from the fish effluent that has broken down and gone through nitrification. However, some studies have shown that the concentrations of nutrients are not sustained over time if a non-supplemented fish diet is used (Somerville et al., 2014; Al-Hafedh et al., 2008). Some studies have indicated that potassium, iron, and calcium need to be incorporated within the system in order to have continued

healthy plant growth (Sommerville et al., 2014; McMurty, 1997). These nutrients are often added as salts are used to balance the pH (e.gpotassium hydroxide and calcium hydroxide).
1.1.5 Aquaponic System Potential
As development of aquaponic systems spreads, many more individuals and companies are realizing the benefits that aquaponics can offer, both environmentally and economically.
It is estimated that aquaponics uses about 10% of the water compared to soil crops (Somerville et al., 2014; Lennard & Leonard, 2006). Water in soil crops is lost from evaporation, transpiration, percolation in the subsoil, runoff and weed growth (Somerville et al., 2014) Water use is at a minimum in aquaponic systems on the other hand, and may have only a 1.4% daily water replacement (Al-Hafedh et al., 2008). The only water loss is through crop growth, transpiration through leaves, and negligible evaporation from the soil-less media. Because of this, the potential for aquaponics where water demand is high or expensive should be further explored (Summerville et al., 2014).
In most aquaponic systems, artificial fertilizers are not used, which reduces environmental pollutants and significantly reduces costs for the farm operations. Because the crops are all grown soil free, there are no soil-borne diseases, no weeds and no tilling required. Many aquaponic facilities are either constructed in greenhouse or in tropical climates, and therefore can produce food year round and in places with poor soil quality.
One of the other major benefits aquaponics provides is low output of waste products, whereas hydroponics, aquaculture, and conventional agriculture can all have significant waste production. For either closed or open hydroponic systems the nutrient solutions become out of balance and unusable, and the systems must be flushed about once every 30 days (Storey, 2016). The waste water is normally disposed of down into drains, and is filtered by the citys water treatment facilities (Quinta et al., 2013). In the long run, this solution may

not be efficient as facilities often require more money to deal with pollution loads that the hydroponic facilities are producing, and in some cases may not even be able to extract all of the excess nutrients. Dumping into water sources is highly regulated, with pressures from the Environmental Protection Agency (EPA), United States Department of Agriculture (USDA), Natural Resources Conservation Service, and State and Regional Water Quality Control boards. Because of this, many growers find it hard to legally dispose of this water without violating the Clean Water Act (Clean Water Act, 1972). The Clean Water Act maintains that it is unlawful to discharge pollutants into water unless a permit is obtained. The main components of hydroponic waste are phosphates and nitrates, which can lead to over nourishment in bodies of water in a process called eutrophication. This will result in algal blooms, which can deoxygenate the water and release toxins, often killing the flora and fauna within. Wetland based waste water treatment options are being researched as a sustainable solution to naturally filter the water (Quinta et al., 2013).
In order to maximize aquaculture production, efficient waste and solid collection methods are important. Ammonia is the primary waste product excreted by fish across the gills as ammonia gas (Rakocy, 1992). Un-ionized ammonia is extremely toxic to fish and can cause tissue damage at concentrations as low as 0.06 ppm (Rakocy, 1992). 998 grams of ammonia are produced from 45 kilograms of fish feed, and therefore the filters in aquaculture are a crucial component of production (Rakocy, 1992). Fish effluent is characteristically high in nitrogen, phosphorus and sulfate depending on the fish feed in use. In a levee style catfish ponds, nutrient input and output were measured (Tucker, 2009). The excreted nutrient contents were very high in excess nutrients with nitrogen averaging 448 kg/ha and phosphorus averaging 90 kg/ha (Table 1).

Table 1. Nutrient waste in a Levee-style catfish pond. The above concentrations were measured, which demonstrates the high nutrient waste generated through aquacultural production (Tucker, 2009).
Nitrogen Phosphorus
In feed (kg/ha) 560 112
Excreted (kg/ha) 448 90
Many aquaculture facilities dispose of their waste water directly into waters of the United States, and therefore the EPA has set guidelines and regulations on what can be disposed of (EPA, 2012). There are currently no numeric limits, but instead requiring best management practices to control the discharge (EPA, 2016).
Traditional agriculture presents one of the largest water and nutrient concerns. World agriculture requires approximately 70% of the fresh water withdrawn per year (Pimentel, 2004). For example, soybeans require 2,000 liters of water per kilogram of crop output, rice requires 1,600 liters per kilogram, and wheat requires 900 liters of water per kilogram of output (Pimentel, 2004). Research also projects that we are severely over fertilizing crops. A study on corn fertilization showed a comparison between North China and United States fertilization rates. China input 588 kilograms of nitrogen/ hectare a year, and 92 kilograms of phosphorus per hectare a year with an output of 8,500 kilograms of com/ hectare a year, while the US input 93 kilograms of nitrogen/hectare and 14 kilograms of phosphorus/hectare with an output of 8,200 kilograms of corn/ hectare (Vitousek, 2009). New solutions are needed to combat both the nutrient discharge problems associated with hydroponics, aquaculture, and conventional agriculture.

1.2 The Importance of Alternative Food Systems
1.2.1 Climate change threatening food security
The global food system contributes 21%-23% of total CO2 emissions, 55%-60% of total CH4 emissions, and 65%-80% of total N2O emissions (Edenhoger et al., 2014). In 2014, the Intergovernmental Panel on Climate Change (IPCC) reported with medium confidence that the estimated temperature increases of 2C or more will negatively impact production of major crops by reducing production and increasing environmental threats to crops (Edenhoger et al., 2014).
Current agricultural methods are extremely vulnerable to present, and future, effects of climate change (Nelson, 2009). It is predicted that climate change will impact agriculture biologically to the extent that the consequences will affect human health. Variation in precipitation may result in short-term crop failures, and long-term production decline. Decreased crops yields will in turn effect production, consumption and prices, which will likely reduce per capita calorie consumption, and increase child malnutrition (Nelson, 2009). It is projected that by 2050 child malnutrition will rise by 20% due to the decrease in calorie production (Nelson 2009). Changes in death rate frequency will also influence the human population size.
1.2.2 The growing population: water andfood demand
One of the major problems facing future food producers is how to increase yields for the growing population, while simultaneously using less land. The human population count on November 2016 has reached 7.4 billion people, with an exponential projected growth for the next 100 years (US Census, 2016). The future population growth is largely dependent on the reproductive and death levels within the next 40 years (Cleland, 2013). In 2100, the population estimates range with low projections of 6.2 billion to high projections of 15.6 +

billion; however, if fertility levels remain the same worldwide as they were in 2005-2010, then the population would exceed 25 billion (United Nations, 2015). Despite these large ranges of estimates, many experts have predicted that population increase will level off at about 10 billion which has been predicted as the earths carrying capacity (Cleland, 2013; Barret & Odum, 2000). Carrying capacity is defined as the population size the world can support without damaging natural, cultural, and social environment and leaving future carrying capacities intact (Aberneth, 2001; Barrett & Odum 2000). Thomas Malthus in 1798 discussed these principles in An Essay on the Principles of Population which describes how human population growth is exponential, whereas natural resources grow arithmetically. From this we can deduce that the population will at some point be unable to produce enough food to support survival (Barrett & Odum, 2000). The long-term sustainability of the earths human population depends on how countries handle human reproduction strategies, and the ever pressing issue of how to produce larger quantities of food using fewer resources.
Even the population growth within the next 40 years will have major effects on the global food supply chain as there will be approximately 2 billion more mouths to feed. The demand for food during this period is predicted to increase by 50%, compared to the 30% population growth (Barrett & Odum 2000). Misuse of soils, over-grazing, aquifer depletion, and loss of biodiversity and ecosystems will be some of the inevitable consequences if we do not act quickly. Aquaponics may be an effective solution to offset some of these concerns by providing high vegetable and fish yield using no soil, minimal space and water, and increased growth rates compared to soil crops (Al-Hafedh et al., 2008).

1.3 Relevant Background
1.3.1 Flourish Farms
This life cycle assessment was conducted at Colorado Aquaponics Flourish Farms, in Denver, Colorado. This aquaponic farm is located within the GrowHaus, on York St. and 1-70, in the Elyria-Swansea neighborhood. The GrowHaus is in a repurposed 1,858 square meter greenhouse from the 1970s, which functions as a non-profit indoor farm, marketplace and educational center. They aim to create a community-driven, neighborhood-based food system by serving as a hub for food distribution, production, education and job creation (www.GrowHaus. com).
Food is produced year-round at the GrowHaus with three separate sustainable and innovative indoor growing farms: hydroponics, permaculture and aquaponics. The scope of this study will concentrate on the aquaponic farm Flourish Farms which occupies 297 square meters within the GrowHaus (Fig. 6).

Figure 6. Schematic of Colorado Aquaponics Flourish Farms. The image depicts the integration of deep-water culture (DWC), nutrient-film technology (NFT), and media beds for growing produce (Images used with permission from JD Sawyer).
Flourish Farms contains all three types of aquaponic systems (DWC, NFT and media beds) as the owners showcase the various construction designs for aquaponics systems. The farm used a tilapia and koi carp combination for many years, due to these fishs resilience and fast growth rates even under high stocking densities (Fig. 7).

Figure 7. Flourish Farms deep water culture and main fish tank. (A) DWC raft system. The image shows the four raft beds that carry the leafy greens vegetable output. (B) Fish production. This tank picture demonstrates the tilapia and koi fish that supply the nutrients for the system (
However, throughout 2014 and 2015 they switched to striped bass, recognizing a greater value and preference for this fish in their customer core (Tawyna Sawyer personal communication, 2015). They have also successfully raised catfish and bluegill. Since Flourish Farms moved into the GrowHaus in 2012 they have grown hundreds of different

varieties of vegetables and have sold over 13,608 kilograms of food within an eight kilometer radius. They also continue to donate 10% of their crops to the GrowHaus, contributing to the local community (Tawyna Sawyer, Personal communication 2015).
Flourish Farms was founded in 2009 by owners and CEOs Tawnya and JD Sawyer. The farm serves not only as a commercial production center, but also as a model system that has been mimicked in schools, community buildings, correctional facilities, and homes. As part of Colorado Aquaponics mission, they provide aquaponic training, curriculum, consultation and support programs that can be delivered to individuals, schools, institutions and communities looking to take charge of their own sustainable farming and food security (
1.3.2 Elyria Swansea neighborhood
One of the GrowHauss main priorities is to provide fresh produce and protein to the Elyria Swansea neighborhood and zip code 80216 in which they are located (Fig. 8).

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Figure 8. Boundaries of Denver, Colorado zip code 80216. This area includes the Elyria Swansea neighborhood as well as sections of Northfield, and the River North Art District. The white star indicates the approximate location of the GrowHaus within this neighborhood (Google Map Data).
The Elyeria Swansea neighborhood was established in 1880 as a working class community and has long been surrounded with industrial buildings and transportation infrastructure. This neighborhood is well known for being the most polluted zip code in the state (Fig. 9).


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Figure 9. Major Toxic Releasing Inventory (TRI) facilities and super fund sites in or next to zip code 80216. See Appendix A for full listing of Sites and Contaminants. There are 8 Superfund sites in this area, with the most toxic release in this zip code has an EPA Hazard ranking of 70.71 (max 100), and the top ten TRI facilities release 132,342 kilograms of toxic chemical per year (last recorded in 2013). In the above map these are labeled 1 10, and the other blue squares indicated other reporting facilities in this area (NIH TOXMAP, 2013).
In this neighborhood there are approximately 10,700 residents, out of which 36% live in poverty with the lowest average household income in the state and 34% are under the age of 18 (Cran Communications Inc., 2015). The residents here have long lacked access to healthy, affordable food, and the area is classified as a food desert in accordance with the USDA definition (Fig. 10).

Figure 10. Denver County food deserts. The above shaded areas are the 19 census tract areas that are classified as a food desert based on the USDAs definition (USDA Data, Google Earth Image).
Food desert is a term that has been used in public health and academia in order to describe the food insecurity associated with residents in a geographical area having little access to healthy food. The USDA quantifies this as a low-income census tract area where a substantial number or percentile of residents have low access to a supermarket or a grocery store. Low income is described as fitting the eligibility requirements of the Treasury Departments New Market Tax Credit program. An area described as low access is further than one mile from a supermarket or grocery store in an urban area, or ten miles in a rural area (Dutko et al., 2012).
In order to combat this food injustice, the GrowHaus offers their weekly, year-round food box at a discounted price for these residents. The food boxes include local fresh farm eggs, and fruit and vegetables from local and often organic farmers. They also include organic leafy greens from their own aquaponics and hydroponic systems. Each weakly box also

includes a complex carbohydrate of either freshly baked bread or tortillas (
In addition to selling produce and fresh fish to the residents in the nearby neighborhood, Flourish Farms sells the majority of its produce to top restaurants in Downtown Denver, all within five miles of the farm (Appendix A). These restaurants include The Populist, The Plimoth, Vesta Dipping Grill, Jax Fish House, Thump Cafe, SAME Cafe, Mondo Market at the Source and Marzycks Fine Foods (
1.4 Life Cycle Assessment Practices
This research investigated the environmental sustainability and cost effectiveness of an alternative for producing local food. Although there are many aquaponic systems in production, especially in the last few years, little research has been conducted on the cost effectiveness or ecological efficiency of aquaponics. In order for aquaponics to be considered as an alternative food system this analysis is critical and necessary in order to justify large investment and production.
One of the most widely used techniques to determine the environmental impacts of a system is a Life Cycle Assessment (LCA). LCA assessment began in the 1960s when scientists concerned with fossil fuel depletion and natural resource loss were seeking a method to evaluate resource consumption (Svoboda, 1995). An LCA is defined as a systematic evaluation of the environmental aspects of a products life cycle stages. These stages can include a cradle to grave approach, which implies considering a products life from raw material acquisition, to manufacturing, product assembly, maintenance, product disassembly and disposal (Akundi, 2013). Rebecca Bainbridge completed the first LCA of a temperate aquaponic system in 2012, looking at environmental implications such as the global warming potential, non-renewable energy use, eutrophication potential, acidification

potential, and water dependency. This report is an important first step, but many questions and variables remain to be tested which this study hopes to achieve.
An LCA first compiles an inventory of relevant energy and material input, as well as releases. These components are then evaluated and for the potential impacts of the inputs and releases (International Organization for Standardization, 1997). Once this is completed, an improvement analysis can be conducted in order to determine opportunities to reduce energy, material inputs, or environmental impacts at each stage of the life cycle. LCAs have recently taken on importance in environmental policy making, as global stakeholders are beginning to feel pressure to reduce their environmental impact (Goedkoop et al., 2013). From the international concern, the International Organization for Standardization (ISO) created principles and framework for voluntary, consensus-based, LCA standardizations for countries to follow so that studies across that world can be compared to combat global problems. LCAs provide the quantitative data for discussion and initiative to take place in order to reduce environmental impact.
The methods for conducting an ISO 14040 LCA consist of four phases (ISO, 2006; Fig.
1. The goal and scope will define the purpose and system
2. The inventory analysis will list the materials and energetic inputs
3. The impact assessment will evaluate the environmental effects
4. The interpretation stage will conclude with recommendations for improvements.

Figure 11. Phases of a Life Cycle Assessment. (ISO 14040, 1997).
1.4.1 Goal and scope description
The first step of an LCA is to define the goal and scope of the system. This step includes many variables and questions that must be determined before the start of the project. There must be a clear reason for executing the LCA, a precise definition of the product and its functional unit, the system boundaries, data requirements, data assumptions, intended audience, how the results will be communicated, and how a peer review will be made (Goedkoop et al., 2013). There are many different approaches to completing an LCA depending on goal, resources, and data available. There are three different orders of LCA analysis (Goedkoop et al 2013):
I. Only the production of materials and transport and included
II. All processes during the life cycle are included but the capital is excluded

III. All processes including the capital goods are included. Usually the capital goods are modeled in a first order mode, so only the production of materials needed to produce the capital goods are included.
Many LCAs do not include capital goods, which can reduce the data requirements for the analysis. In some systems capital contributes up to 30% of the environmental impact, so it can be beneficial to include the data in the boundaries (Goedkoop et al., 2013). LCAs can also differentiate on whether it includes the entire scope of environmental impact or focus in on single issues, such as carbon footprinting or water footprinting. In general the impact categories include (Goedkoop et al., 2013):
Non-renewable resources (with and without energy content)
Renewable resources (with and without energy content)
Global warming (CO2 equivalents)
Acidification (kmol H+ equivalents)
Ozone layer depletion (kg CFC11 equivalents)
Photochemical oxidant formation (kg ethane-equivalents)
Eutrophication (kmol N+ equivalents)
The boundaries of an LCA also include establishing the scope of the environmental issues that will be reported, such as greenhouse gases. GHGs are classified into three different scopes based on the GHG Protocol Corporate Standard. Scope 1 emissions are directly from sources that are owned or controlled by the system, such as vehicle emissions or emissions from chemical production. Scope 2 emissions are indirect emissions from sources that are purchased by the system, such as the emissions generated from purchasing energy, where the emissions occur at the facility where the energy is generated. Scope 3 emissions are additionally indirect emissions that are not reported in Scope 2, that are in the

value chain of the reporting company, both upstream and downstream. Scope 3 emissions include extraction and production of purchased materials. LCA software has Scope 3 emissions databases for all processes that are reported.
1.4.2 Inventory analysis description
The inventory analysis encompasses the task of collecting the necessary data in order to perform the LCA. There are two types of data, foreground data which refers to data that describe a particular product, and background data which are data for the production of generic materials, energy, transport, and waste management. Foreground data must be collected from the system itself, whereas LCA software, such as GaBi V5.0, contains the necessary background data, such as the scope 2 and 3 emissions of certain processes. LCA software helps to manage data and model the LCA within the ISO standards. GaBi V5.0 has several options for creating process maps and flows and has several analyzing and interpreting selections ( Questionnaires are often helpful during foreground data collection in order to gather all required information. In order to gain the background data, the GaBi V5.0 software has a database covering 10,000 processes in the Ecolnvent and U.S. LCI databases (Goedkoop et al., 2013).
1.4.3 Impact assessment description
Impact assessment of an LCA is an analysis to determine environmental impacts throughout a products lifetime. This phase is aimed at understanding and evaluating the significance of impacts of the production system (Goedkoop et al., 2013). In order to do this in compliance with the ISO, a classification and characterization need to take place. GaBi V5.0 software has many available impact assessment methodologies built in to its program that can be used depending on the goal and scope of the system. The results will typically display which inventory items are contributing to the environmental factors, and to what

degree. The impact assessment analysis can have many stages, including; allocation, total resource use calculations, library determination, and conversions. If necessary, allocations will be determined by the end user. Library determination depends on what software databases are available, and which elements the end user is trying to analyze. Conversions into the same function output unit are typically done within the software.
1.4.4 Interpretation stage description
The interpretation stage is described by ISO 14044 as the number of checks to test whether conclusions are adequately supported by the data (2006). In GaBi V5.0 software this exists as a checklist that will review relevant issues mentioned in the ISO standard. These exist mainly as uncertainty in the analysis, such as variation in the data, correctness of the model, and incompleteness of the model. Once these aspects are evaluated, the model can be looked at to see if any hot spots exist, or areas of consumption that are causing large environmental impact. These hot spots can be recommended for system improvement design changes in order to reduce environmental impact. This stage will also be used to compare the results of an LCA to another applicable system or product in order to discern which system can have more viability and less environmental impacts long-term.

2.1 Introduction
This research assessed the operational production and sustainability potential of Colorado Aquaponics commercial system Flourish Farms located in Denver, Colorado in the United States. Aquaponic farming is a promising technology for local, sustainable food production. Aquaponics combines aquaculture and hydroponics in a recirculating engineered ecosystem that utilizes the effluent from aquatic animals rich in ammonium by circulating it to nitrifying rhizobacteria to fertilize hydroponic vegetables. Nitrosomona species oxidize the toxic ammonia (NH3) into nitrite, and then Nitrospira bacteria oxidize nitrite (NO2") into nitrate (NO3'), which is less harmful to the fish, and a nutrient for the plants. The water, now stripped of most ammonia and nitrates after flowing through the bacteria matrix and root system, circulates back to the aquaculture subsystem (McMurty et al., 1997) This system design can annually produce up to 41.5 kg/m3 of tilapia and 59.6kg/m2 of tomatoes in a 1.2m wide, 0.33m deep and 0.86m long tank with 4 plant plots (McMurtry et al., 1997).
The global food production system is projected to decline in crop output due to climate change (Nelson, 2009), and population growth will continue to exceed the carrying capacity of the planet (Barrett & Odum, 2000), which will lead to a greater percentage of the worlds population receiving inadequate nutrition on a daily basis. Current agricultural methods are some of the primary contributors to climate change and environmental degradation, and if they are further expanded to meet the increasing demand, environmental collapse is expected (Edenhoger et al., 2014).
In place of a global food production systems, hydroponics, aquaculture, urban gardening, and local food production offer an alternatives, and aim for a healthier and more sustainable

crop output while revitalizing the environment. Aquaponic technology is a system designed to produce protein and vegetables using minimal resources and waste production.
Aquaponics also offers a solution to the difficulties of acquiring protein locally and affordably. One four ounce serving of tilapia incorporates 50% of the daily protein requirements for men, and 60% for women (USDA SR-21, 2014). This technology is still used as a niche farming method with only 257 systems out of the 809 United States systems surveyed in 2014 operating on the commercial scale, with all others classified as backyard or hobby systems (Love et al., 2014). However, aquaponics is a rapidly growing field as over 600 systems have been built in the United States from 2010 to 2013 (Love et al., 2014). Completing a Life Cycle Assessment on one of the well-founded commercial systems in Denver will elucidate the WD, EU and GWP of this aquaponics system.
2.1.1 Research Objective
In order to further examine and assess aquaponics as a method to grow high quality food, we performed an LCA on the commercial aquaponics system in Denver, Colorado, which compared the GWP, WD and EU to literature recordings of resource use in conventional agriculture, aquaculture, and hydroponics. This analysis will enable the end users to take into account where inefficiencies in the aquaponic process may exist, and how to improve operations for a more sustainable system. The literature comparisons will help those interested in the aquaponic field to understand the benefits and resource requirements for the system, in contrast to other available options.
2.1.2 Study Site
The LCA took place at Flourish Farms, run by Colorado Aquaponics, within the GrowHaus. The GrowHaus is in a historic 1,858 square meter greenhouse which functions as a non-profit indoor farm, marketplace and educational center. They aim to create a

community-driven, neighborhood-based food system by serving as a hub for food distribution, production, education, and job creation ( Food is produced year-round at the GrowHaus with three separate sustainable and innovative growing farms: hydroponics, permaculture and aquaponics. The scope of this study will concentrate on the aquaponic farm Flourish Farms which occupies 297 square-meters within the GrowHaus.
Flourish Farms was founded in 2009 by owners and CEOs Tawnya and JD Sawyer. The farm serves as a commercial production center and as a model system that has been mimicked in schools, community buildings, correctional facilities, and homes. As part of Colorado Aquaponics mission, they provide aquaponic training, curriculum, consultation and support programs that can be delivered to individuals, schools, institutions and communities looking to take charge of their own sustainable farming and food security (
The farm contains three types of aquaponic systems, deep water culture (DWC), nutrient film technique (NFT) and media beds, as the owners showcase the various construction designs for aquaponics systems. Flourish Farms used a tilapia and koi carp combination for many years, due to their resilience and rapid growth under high stocking densities. However, they gradually switched to hybrid striped bass (HSB) in 2014 and 2015, recognizing a greater value and preference for this fish by their customers (Tawnya Sawyer, personal communication 2015). They have also successfully raised catfish and bluegill. Since Flourish Farms moved into the GrowHaus in 2012, they have grown hundreds of different varieties of vegetables and have sold over 13,607 kg of food within an eight kilometer radius.

2.2 Methodology
The LCA follows the ISO 14040/14044 guidelines (ISO, 2006) and is separated into four sections: (1) goal and scope definitions; (2) inventory analysis; (3) impact assessment and (4) interpretation (as presented in the Results and Discussion section of this paper).
2.2.1 Goal and scope
This LCA is considered a streamlined LCA, as several processes in a cradle-to-grave analysis were omitted for this study. However, streamlining the LCA process is an essential element in the goal and scope definition, as few LCAs are full-scale due to time and cost constraints, according to Todd & Curran (1999). Streamlining allows the study designers to select an approach and level of rigor that is appropriate for the intended end users and application of the study.
In this research, the goal of the study was to determine the life cycle GWP, WD and EU from a commercial aquaponic system in Denver, CO. A second goal was to compare the results from this study to other literature LCA values from hydroponics, aquaculture and conventional agriculture to evaluate if any of these systems offer environmental efficiencies for agricultural production. These goals were achieved by forming a functional unit, constructing system boundaries, and gathering the required data.
In order to accommodate for the production of two products in this agricultural system, two separate LCA analyses were completed with allocations for resource use. The functional unit for the lettuce production is 1 kg WM lettuce. Dry mass (DM), although a more accurate measure as it excludes fluctuations in water concentrations, was not used for this study as Flourish Farm measures every full lettuce head weight right after harvest and before delivering to the costumer. Flourish Farms produced 60 different types of leafy greens during the 2014 year (Appendix B), which for this study will all be referred to as lettuce. Each

species of lettuce was weighed at harvest and recorded and the average sell weight was calculated. The second LCA analysis focuses on the fish production of the aquaponic farm, with a functional unit of 1 kg of fish. Flourish Farm produced two different species of fish during 2014, tilapia and HSB which both together will be referred to as fish. For this analysis, a fish mass estimation had to be used, as the farm currently sells their fish whole and only occasionally weighs them. Fish mass was estimated from personal communication with owner Tawnya Sawyer, as well as notes in the sales section of the data report indicating approximate fish size and occasional weights. The weights were categorized into small (~28gm), medium (~170gm) or large (~396gm) for each fish sold.
The system boundary is a single issue LCA approach, with an Order I analysis focusing on the production cycle and transportation of the farm in order to ascertain the global warming potential, energy and water use within the farm for the entire 2014 year. The scope includes the energy carriers, natural gas consumption, water use, integrated pest management, delivery transportation, and the input of fish feed into the system (Goedkoop et al., 2013; Fig. 12).

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Figure 12. System Boundary Colorado Aquaponics Flourish Farms LCA. The above figure demonstrates a flow diagram of the boundaries of the LCA for this study. This study included the fish feed production, water acquisition, water use, pump use, lighting use, integrated pest management, heating and cooling mechanisms and the transport to the customers. Excluded from the study were the nutrient additions and the background analysis of the capital units used in production and transportation.
In order to clarify the system boundaries, the components were divided into pre-farm, on-farm and post-farm, which will help elucidate the areas outside of the system boundary (Table 2).

Table 2. Pre-farm, on-farm and post-farm inclusions and exclusions in this study.
Pre-Farm On-Farm Post-Farm
Inside Fish feed production Heating Transport to
Study Pest management Cooling customer
Boundary production Lighting Pumps Water
Outside Infrastructure Nutrient Packaging
Study production additions Storage
Boundary Capital production Consumption
Nutrient production stage
Materials transport to Waste
farm generation
The WD and GWP were both calculated using GaBi Product Sustainability Software version 5.0. GaBi V5.0 which generates the LCA of a product according to the ISO 14040/14044 regulations, and uses the PAS 2050 and GHG Protocol Product and Scope 3 Standard to specifically generate the carbon footprint. For this study, the GaBi V5.0 International Reference Life Cycle Data System (ILCD) was used, using the U.S. Life Cycle Inventory and Ecolnvent databases.
Outside of the scope of the study were the capital resources of the farm, which included the cradle production costs of greenhouse structure, tanks, piping, motors, heaters, fans, lights and additional building materials. Additionally, the functionality of this study for Colorado Aquaponics did not need the extensive rigor to include the capital, but rather focusing on the production hot spots accomplished the goal. In future studies of the farm,

these elements could be inventoried and included. Also, many of the nutrient additions to the farm in 2014 were not categorized for which chemicals were included. For instance, a homebrew nutrient mixture compromised 90% of the total nutrient additions for 2014, but this mixture was constantly changed and no notes were provided as to what was included in each supplement. Because of these inconsistencies, the nutrient additions were excluded. However, the main nutrient supply to the system is the fish effluent, which has zero environmental impact, and allows comparison of this study to others that do include nutrient additions. Other limitations were the specific integrated pest management chemicals that were used were not available in either database. However, a general pesticide application was found which was used for this study. The water use in this study was pulled from the Denver Water meter bills, and included all of the use on the farm not just the usage for production. In future studies, calculations could be made to determine the water use just for production and exclude all other operations.
2.2.2 Life Cycle Inventory
The life cycle inventory considers all of the necessary inputs and outputs that occur during the life cycle of the product. The process data were collected directly from Flourish Farms owners and within the detailed records of produce and fish species output, fish food input into the system, pest management use, electrical use, water bills, natural gas consumption, and necessary equipment for operational activity. The life cycle inventory shows all of the inputs into the system in order to produce 1 kg of lettuce and 1 kg of fish (Table 3).

Table 3. Life Cycle Inventory of Flourish Farms.
Inputs Value Units
LCI of 1 kg fish Fish feed 0.69 Kg
Pesticide production 0.0332 Kg
Market for tap water 272 Kg
Market for electricity 0.00843 mW h
Market for natural gas 4.83 kg
LCI of 1 kg lettuce Fish feed 0.054 Kg
Pesticide production 0.00259 Kg
Market for tap water 130 Kg
Market for electricity 0.00365 mW h
Market for natural gas 4.83 Kg
Transport to costumer 4,970 kgkm
These values correspond to the process flows created within the GaBi V5.0 software (Fig. 13 & 14).
Figure 13. Life Cycle Assessment Process Flow for Fish. This image, taken from GaBi V5.0 software, exhibits the inputs into the database for the production of 1 kg of fish from the farm.

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Figure 14. Life Cycle Assessment Process Flow for Lettuce. This image, taken from GciBi V5.0 software, exhibits the inputs into the database for the production of 1 kg of lettuce from the farm.
These values were calculated from monthly utility meter readings of the natural gas and water use. Additionally, electrical consumption was calculated from the kWh operational data listed on each piece of equipment for the foreground analysis. The operational equipment background data was excluded from this study. The building uses equipment to control temperature, humidity, lighting, and water flow. These include five horizontal airflow fans, two vent fans, a wet wall pump, circulation pump, four HID metal halide lights, intermediate bulk container power pumps, a main MDM Inc. ValuFlo 6100 water pump (Colorado Springs, CO), two media bed water pumps, an NFT pump, three nursery pumps, one tower pump, and an S31 regenerative air blower. The system also uses fish tank boilers, known as fish sweaters and two Modine heaters (Racine, WI) to heat the water and greenhouse respectively. Each piece of electrical equipment was evaluated for the average hours per day it would run, and seasonal variation was calculated as well (Table 4).

Table 4. Electrical Operational Equipment at Flourish Farms. The following equipment was all researched for kilowatt hour capacity, seasonal use, daily use, and number of units. This combined information was used to calculate the total kilowatt requirements for the farm, and was then converted into megaJoules for the ELI factor for this study.
Component Units kWh Watts Operational Hours Operational Days
HAF Fans 5 0.575 115 23 120
Modine Heaters 2 0.250 125 4 365
Vent Fan A 1 0.560 560 4 365
Vent Fan B 1 0.560 560 2 365
Wet Wall Pump 1 0.060 60 0 120
Circulation Pump 1 0.006 16 0 120
HID Metal Halide Lights 4 1.600 400 6 120
IBC tower pump 1 0.145 145 0 365
ValuFlo 6100 Water Pump 1 0.207 207 24 365
Media Bed Water Pump 1 0.058 58 24 365
Media Bed Water Pump 1 0.033 33 24 365
NFT Pump, Model 18B 1 0.145 145 0.5 365
Nursery Pump 1 1 0.138 138 0.5 365
Nursery Pump 2 1 0.104 104 0.5 365
Nursery Sump Pump, Model 18B 1 0.180 180 0.5 365
S31 Blower 1 0.471 471 24 365
Tower Pump 1 0.070 70 24 365
These values were summed to produce the total kWh the farm uses in one year. This value was converted into megaJoules for this study, and reported as the ELI. Additionally, having this inventory analysis of the operational equipment allows the end user to highlight which machinery contributes the most to the environmental impact.
In order to calculate the GWP, the cubic feet of compressed natural gas used in the Modine heaters and aquaponic hot water heaters where converted into kilograms of CO2 production using equations in the Chemistry of the Elements (Greenwood & Eamshaw, 1997). The CO2 emissions (calculated from kg/km) for the transportation to Flourish Farms

customer base were also added into the GciBi V5.0 software. These values were then divided
by the total kilograms of lettuce and fish to produce the kg CO2 e/kg value. The kg CO2 e/kg emissions from the electrical components of the system, lights, fans, heaters, and pumps, were included into the total GWP calculation as well.
The WD data were collected using meter pulls from Denver Water for the farm within the GrowHaus through 2014. These data include all water used by the farm, not just what would be inserted into the system to replace daily evaporation and transpiration. However, the majority of water use at the farm is used for replenishing water lost from transpiration, plant mass growth and evaporation.
Flourish Farm obtains its Pond Low-Energy fish feed from Skretting USA, a Nutreco company. LCA data were obtained from the Skretting Australia Annual Sustainability Report (2014), a cradle to gate LCA analysis, which was incorporated into the study to account for GWP, EU and WD for the farms fish feed input. Eutrophication data were not included in the sustainability report. To date, an LCA has not been completed for the U.S. site, so the data from the Australia facility were used as a close comparison. The products components are listed in Figure 15.
Product Floating Size (mm) Protein (min) Oil (min) Moisture (max) Fiber (max) Ash (max) DE* (MJ/kg)
1 Pond LE 3.5 32% 6% 10% 5% 10% 13.0
Pond LE 4.5 32% 6% 10% 5% 10% 13.0
1 Pond LE 5.5 32% 6% 10% 5% 10% 130
Pond LE 7.5 32% 6% 10% 5% 10% 13.0
'DE = Digestible Energy
Figure 15. Skrettings Pond LE fish feed components. Flourish farms uses the 5.5mm floating size (

The transportation greenhouse gas emissions were calculated using a list of the delivery locations and frequency reporting from the farm. Flourish Farms delivers their own produce and all fish are sold at the GrowHaus facility. In order to calculate the average delivery weight, nine deliveries were categorized into product type and weighed, and then that average was used for other calculations. The optimal route was computed using Googles OptiRoute by inserting the 21 delivery locations (Fig. 16; Appendix A). This route was not used by Flourish Farms every week, as errands and deliveries varied, but is an average approximation for the year. The mileage for each trip from OptiRoute was multiplied across the number of deliveries per year to obtain the total mileage for 2014.

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Figure 16. Flourish Farms delivery route. Flourish Farms delivers to 20 businesses in the surrounding Denver area. Each trip is 24.3 miles round trip, and the deliveries are taken twice a week. See Appendix A for delivery locations.
Although the aquaponic farm used eight various integrated pest management techniques (Appendix C), none of these were available in the GaBi V5.0 database. Conversely, a generic pesticide production database was available, which was used for this study. Flourish Farms pest management focuses on low environmental impact products, and the GaBi V5.0 database option does not include this. As a result, the environmental impact from the pest management may reflect slightly higher outcomes than the actual pesticides used would represent. However, the pest management is a minor input category, so the effects from this discrepancy are not considered to be significant.

The aquaponic farm contains many capital components in order to run at a commercial scale. Although the background data from these components were not included in this LCA, the infrastructure is listed in Table 5 in order to gain an understanding of the scale and space required for this facility to operate.
Table 5. Necessary infrastructure in Flourish Farms aquaponic system. The following materials are the entire main infrastructure in Colorado Aquaponics farm.
Component Volume (m3) Dimensions (m)
Raft Bed 1 (Media and DWC) 7.86 1.22 Wx23.16L
Raft Bed 2 DWC 7.86 1.22 Wx23.16L
Raft Bed 3DWC 5.76 1.22 Wx 7.92 L
Raft Bed 4 DWC 11.52 2.44 Wx 23.16 L
NFT Pumps - 30.48 L
Wood Fish Tank 2.03 0.92 Wx 3.35 Lx 0.61 Deep
Main Fish Tank 3.18 2.29 Diameter x 1.02 Deep
Blue Tank (Cone Bottom) 1.76 1.57 Wx 1.57 Lx 0.71 Deep
Brush Filtration Tank 0.68 0.66 Hx 1.35 Lx 0.94 W
Clarifier Filter (Cone Bottom) 0.45 0.71 Diameter x 1.47 H
The main infrastructures are four raft beds (three DWC, and one with both DWC and media), 30m of NFT, a 2m3 wooden fish tank for younger fish, a 3m3 main tank for mature fish, and a 1.76m3 cone bottom tank. There are also two filtration systems to remove solids from the effluent in order to prevent waste accumulation and root damage. The entire system is housed in a repurposed greenhouse that was constructed in the 1970s. The greenhouse was renovated to be a growing environment in 2012 (JD Sawyer personal communication, 2016). 2.2.3 Life Cycle Impact Assessment
The impact assessment calculates the GWP, WD and EU use based off of the values from the inventory analysis. A life cycle impact assessment then transfers the emissions and resource data into indicators that reflect environment and health pressures as well as resource

scarcity (ILCD, 2011). This required a four step process (1) allocating the resources to the two co-products within the system, (2) calculating the total gas use, water use and electricity use produced by each process, and (3) converting the gas use into CO2 equivalency (CO2 e) for the GWP calculation, converting the electricity use into mJ, and converting the water use into m3, as all of these are the standard unit for comparison in LCA studies.
Allocation. Allocation is a partitioning practice used to divide the input or output flows of a process between two or more product systems (ISO, 14044). Since the farm has the coproducts of fish and various produce from the same resources, the input data were allocated to two categories of production using economic profits, as practiced by other aquaculture LCA studies (Ayer et al., 2008). This resulted in 16.3% of the resources contributing to the aquaculture production, and 83.7% of the resources to the lettuce production. From these allocations, two separate LCAs were completed. One using 16.3% of all resource use allocated to aquaculture production, and the second using 83.7% of resource use allocated to lettuce production. This allocation also allowed the LCA results of the fish production in aquaponics to be approximate compared to literature values of LCAs for aquaculture, and the LCA results of the lettuce production in the aquaponic system to be compared to traditional agriculture and hydroponic lettuce production.
Total Resource Use. The inventory analysis was inserted into GaBi V5.0 in order to calculate the GWP, WD and EU for the aquaponic system for 1 kg of lettuce and 1 kg of fish production. The input and output data were linked to Ecolnvent and U.S. Life Cycle Inventory databases in GaBi V5.0. These databases contain data on materials, emissions and energy consumption for the manufacture of one unit of production.
Conversion. Once the inputs are linked to the correct databases, GaBi V5.0 software converts the input unit into the output unit, based on the background database information.

For the GWP conversion, all of the emissions calculations are completed for the electricity use, natural gas use, transportation, and water acquisition. The GWP also included the emissions used to engineer the fish feed and integrated pest management. The software automatically completes any necessary conversion required to account for greenhouse gases that have varying global warming potencies into a standard of 1 kg of CO2. For instance, according to the IPCC CH4 has a global warming potential that is 21 times higher than CO2 over 100 years (IPCC, 1996). The water dependency was converted from kg of water into m3 and incorporated the water used on the farm, as well as the water dependency used for fish feed and the pesticide. The EU for this study was hand calculated, using the conversion factor of 1 kWh to 3.6 megaJoule (mJ), as the GaBi V5.0 software did not report this metric. The International Reference Life Cycle Data System (ILCD) analysis was used as the impact assessment method for this study. The ILCD published the Recommendations for Life Cycle Impact assessment in the European Context which chooses the methodology for each impact category that has been evaluated as the best (ILCD, 2011). Although the Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI 2.1), developed by U.S. Environmental Protection Agency (EPA), can have more contextual significance for a study done in the U.S., TRACI did not include any metrics on water dependency, whereas the ILCD LCIA does include this as an impact category, which was important for this study. The process flows for the lettuce and fish LCIA are shown in Figures 13 and 14.
2.3 Results
Flourish Farms used a total of 14,157 kg of CO2 equivalency in order to produce 2,700 kg of lettuce and 252 kg of fish in 2014. The total 2014 EU for the system was 33,670 mJ, and the WD was 420 m3 for all operations. Flourish Farms had zero material waste, as all solids

removed from the clarifier filter were mixed into a fertilizer solution for use in soil based gardens, lawns, compost and foliar sprays within the GrowHaus. All roots from the vegetables were either sold with the product, or trimmed and used in composting bins. The farm used a total of 0.74 kg of fish feed per kg of combined fish and lettuce production and the farm used 0.04 kg of integrated pest management per kg of production. Flourish Farm delivered 307 kg of produce to their customers, with 4084 kilometers driven throughout the year, from a twice weekly delivery schedule. This accounts for the 13.3 kilometers per kilogram of lettuce delivered. The farm currently sells or donates the remaining 89% of their produce and 100% of their fish within the GrowHaus.
This aquaponic system had a GWP of 12.95 kg CO2 e/kg, which combines the LCA analysis of the fish and lettuce (Fig. 17 & 18, respectively). The EU for the farm totaled 32.38 mJ/kg, and the WD was 0.1945m3/kg (Table 6). The GWP is 63% from the electric requirements, 26% from the natural gas use, 6% from transport to customers, and the remaining 5% was attributed to the pest management, tap water acquisition and fish feed (Fig. 19).

Inputs to the Farm
Figure 17. Global wanning potential of fish production at Flourish Farm.

Inputs to the Farm
Figure 18. Global warming potential of lettuce production at Flourish Farms.
Table 6. The total global warming potential (kg CO2 e), energy use (mJ) and water dependency (m3) for Flourish Farm lettuce and fish per kilogram in 2014.
Mass Produced (kg) Units Produced Economic Allocation (%) GWP (kg CO2 e/kg) EU (mJ/kg) WD (m3/kg)
Fish 252 1,685 16.3 8.50 21.77 0.1350
Lettuce 2,700 30,553 83.7 4.45 10.44 0.0595
Total 2,952 32,238 100 12.95 32.38 0.1945

Tap Water
Fish Feed
Natural Gas 26%
Figure 19. Distribution of global warming potential kg of CO2 e/ kg of production within Flourish Farms.
The results from this study were then compared with results from the literature in order to evaluate the environmental costs of aquaponics contrasted to hydroponic systems, aquaculture systems and traditional agriculture.
In order to compare the lettuce production from aquaponics to hydroponics and traditional agriculture, the resource allocation of 83.7% was used. The allocation percentage was applied to each resource input into the farm for the lettuce LCA. The lettuce production in the aquaponic system had a higher yield than irrigated traditional agriculture by 18.12 kg/m2, and a lower yield than hydroponics by 18.98 kg/m2. The GWP of aquaponics was 4.45 kg of CO2 e/kg, higher than both hydroponics and irrigated traditional agriculture, which

were 0.90 and 0.86 kg of CO2 e/kg respectively. The data indicated that aquaponics had a lower WD than irrigated traditional agriculture by 0.19 m3/kg, but a higher WD than hydroponics by 0.04 m3/kg. EU was the highest in hydroponic systems, with aquaponics lower by 79.42 mJ/kg. Aquaponics had a higher EU than traditional agriculture by 9.48 mJ/kg. The rain fed agriculture had a 21.89 kg/m2 lower yield than aquaponics. However, rain fed agriculture also had the lowest GWP when compared to all other farming systems. The WD of rain red agriculture was 0.02 lower than aquaponics, and 0.02 higher than hydroponics. EU calculations were not available in the Hall et al 2014 study (Table 7).
Table 7. Comparative of annual land use, water dependency and energy use in aquaponics, hydroponics and traditional agriculture for 1 kilogram of lettuce production. The aquaponic data for this comparison used the 83.7% allocation of resources use to represent only the lettuce production component of the system.
Agricultural Type Yield (kg/m2) GWP (kg of CO2 e/kg) WD (m3/kg) EU (mJ/kg) Reference
Aquaponics 22.02 4.45 0.06 10.58 Current study Barbosa et al 2015
Hydroponics 41.00 6.10 0.90 0.02 0.01 90.00 11.00 Rothwell et al 2016
Traditional Barbosa et al 2015
Agriculture Irrigated Traditional 3.90 0.21 0.86 0.25 0.03 1.10 0.08 Plawecki et al 2015
Agriculture Rain fed 0.13 0.08 0.21 0.12 0.04 0.04 - Hall et al 2014
The fish production of aquaponics was then compared to various aquaculture LCA
studies, using the 16.3% allocation of resources. The allocation percentage was applied to each resource input into the study for the fish LCA. This study indicated that aquaponics had a slightly higher GWP compared to other aquaculture systems, except for the arctic char

recirculation system (Ayer & Tyedmers, 2009). While the Bainbridge (2012) and Boxman (2016) aquaponic study showed a mid-range EU, this studys aquaponic system had the lowest EU of all systems. All aquaponic systems had the lowest WD compared to all other aquaculture types (Table 8).
Table 8. Comparison of Global Warming Potential, Energy Use, and Water Dependency of various aquaculture systems with values in terms of one kilogram of fish production. The aquaponic data for this comparison used the 16.3% allocation of resource use to represent only the aquaculture production component of the system.
Fish Type System Type GWP (kg CO2 e/kg) EU (mJ/kg) WD (m3/kg) Reference
Tilapia & HSB Temperate Aquaponics 8.50 21.79 0.135 Current Study
Tilapia Temperate Aquaponics 7.18 121.25 0.01 Bainbridge 2012
Tilapia Tropical Aquaponics 9.52 123.46 -1.50 Boxman et al 2016
Turbot Recirculation 6.02 290.99 4.81 Aubin et al 2006
Rainbow trout Flow through 2.02 34.87 98.80 Roque d'Orbcastel et al
Rainbow trout Flow through 2.75 78.23 52.60 Aubin et al 2009
Rainbow trout Recirculation 2.04 63.20 6.63 Roque d'Orbcastel et al
Seabass Net pen 3.60 54.66 48,720.00 Aubin et al 2009
Arctic Char Recirculation 28.20 353.00 - Ayer and Tyedmers, 20'
Atlantic Salmon Net Pen 2.07 26.90 - Ayer and Tyedmers, 20'
2.4 Discussion
2.4.1 Impact Assessment
The field of aquaponic farming has been rapidly growing over the past decades, but there have been very few rigorous, peer-reviewed systems research published on the topic.
Because of this, assessment of these systems is needed in order to provide stakeholders information on the benefits and costs of aquaponics and the potential these systems have for providing sustainable food production. In a study done by Farahipour et. al., (2014) LCA has

been shown to be capable of producing some nontrivial results that can be significantly helpful when it comes to decision making. This LCA demonstrated that aquaponics has beneficial reductions for some environmental impacts associated with food production, but it has a higher impact in other categories. Aquaponics showed a great potential for increasing yield per land area, while decreasing water use compared to conventional agriculture. The lettuce production in aquaponics was also outperformed by hydroponics in regards to yields and water use. However, this aquaponic system used less energy than the comparative hydroponic studies from the Barbosa et al., study (2015). This study used data focusing on agricultural practices in Arizona, US as 29% of lettuce production nationwide occurs in this state (Barbosa et al., 2015). The conventional agriculture ranges were determined from an order of magnitude study from Acker et al. (2008) that focused on the required energy and water for all lettuce cultivation in Arizona (as well as other crops). The hydroponic data from the Barbosa et al. (2015) study was from an enterprise model from the Ohio State University, used to estimate the revenue, expenses, and profitability associated with greenhouse lettuce production. Data was also taken from two more hydroponic studies to estimate water and energy use. These comparative studies for hydroponics and traditional agriculture in Arizona have a warmer climate than Denver, Colorado. In order to compare how sustainable aquaponics is as a local food production system for this city, it would be helpful to compare to agricultural systems within this state, which so far, have not been completed. Rain fed agriculture, in comparison, had much lower yields than any other production type. However, they had a corresponding low GWP value as well. Although primarily rain fed, the farmers in the Hall et al., study did supplement with irrigation when needed, which resulted in the slightly higher WD than hydroponics. The rain fed agriculture WD was still lower than irrigated traditional agriculture and aquaponics. In regards to fish

production, aquaponics contributed more to GWP than all other types of aquaculture except for an arctic char recirculation system (Ayer & Tyedmers, 2009). However, the EU and WD for this aquaponic study was the lowest of all aquaculture systems, which has the potential for natural resource conservation. The comparison between temperate and tropical aquaponics shows that regardless of the climate, the GWP is still high for the production.
This is potentially from the University of Virgin Islands system focusing primarily on fish production, while Flourish Farms primary product is lettuce. The Boxman et al., (2016) study also used the basil production as a credit to their system, instead of using an additional functional unit. This resulted in several avoided products, which is why there is a negative WD for this system. However, the water additions for the Boxman system were 0.16 m3/kg, which was 0.03 m3/kg higher than Flourish Farms. These comparisons suggest that although it would be logical to assume gained production efficiencies from a tropical climate system that does not need a greenhouse, this is not necessarily the case.
This study identified areas where efficiencies could be built into aquaponics in order to have a more sustainable system. The GWP for aquaponics was higher than other agricultural systems, and could be reduced by the farm considering alternative energy solutions, such as purchasing wind energy from their source. The farm currently has plans to install solar panels which will reduce both the GWP and the EU for the system. Presently 63% of Flourish Farms GWP is from the electrical usage of the farm, and 26% from the natural gas consumption, so this improvement could help reduce these electrical usage components from the farm. One of the hot-spots for electrical consumption was the use of the halide lights for six hours a day during the winter. In the future, converting to LED lights could reduce energy use for this component by 60%, although the greater capital cost for the lights would need to be considered. Part of this high natural gas consumption comes from the temperate

continental climate, which generates hot summers and very cold winters, requiring high temperature mediation. The aquaponic water culture is kept consistently between 21C and 22.7C, and the greenhouse air temperatures range from 12.7 to 23.8C. This amount of temperature control in a drastically changing climate in Colorado is energy intensive to maintain. Another aspect to consider is the building where Flourish Farms is located is in a repurposed historic greenhouse from the 1970s, which lacks modem infrastructure to more efficiently retain heat. Solar thermal heating and water heating could be applied to the building to reduce the GWP, as well as a climate battery, which could store hot air underground to use during the cold weather. One advantage aquaponics has in comparison to traditional agriculture is the local customer base. Flourish farms sells and delivers all of its products within an 8 kilometer radius. One of the potential reasons that the GWP for aquaponics exceeded that of traditional agriculture is the reliance on electricity and heat for the system to operate. While conventional farms do irrigate and have machinery for tilling, weeding and harvesting, rarely are all of these components operating twenty-four seven. In an aquaponic system the water pumps, circulators, aerators, and heating or cooling mechanism need to be on one hundred percent of the time. If one of these elements were to fail, there would likely be a large fish die-off, as there was in this farm when the generators failed. However, the benefit from the constant circulation is the increased yield and year round production, which many Midwestern agricultural systems cannot offer.
During the course of this study, Flourish Farms harvested both tilapia and HSB. HSB was thought to be beneficial because it can be raised in lower water temperatures than tilapia, and therefore saving on water heating costs. However, tilapia and HSB both grow optimally from 23C to 27C. Flourish Farms typically kept water temperatures 1 to 2C lower than optimally growing records. One recommendation was to reduce the water temperature further

while the HSB were the primary species, since they are more resilient under cold conditions than tilapia. Flourish Farms actually did attempt this growing technique to reduce GHG and heating costs. They lowered water temperatures to 10C and found that the HSB were still sustained. However, because the reduced temperatures slowed the HSB growth, the nitrification process slowed as well, doubling the amount of time for the lettuce production to reach harvest size. The reduction in profit harvestable vegetables was actually far greater than the costs saved in heating over the winter.
While the WD for aquaponics was lower than traditional agriculture and aquaculture, it was still higher than the projected 10% of water usage of traditional agriculture that many studies support (Somerville et al., 2014; Lennard & Leonard, 2006; Bainbridge, 2012). This LCA indicated that aquaponics uses 24% less water than traditional irrigated agriculture and in a desert climate. Flourish Farms going forward should carefully track where water is being applied in the system, and look for any possible reductions. Another possible reduction is Denver approved rainwater collection in 2015, which could be another water source the farm could utilize instead of tap water (Gauldin, 2015). The Bainbridge aquaponic LCA predicted that a 0 m3 WD could be achieved in their system by relying on rainwater collection alone (2012). The farm also experienced several operational emergencies during 2014, which could have caused a need for the system to be flushed and heavy water use during this time. Additional years of data and notes of future notes of high water usage may prove that 2014 was an outlier in WD for Flourish Farms.
The lettuce yield for aquaponics shows promise as the production was 560% higher than traditional irrigated agriculture and 16,838% higher than rain fed agriculture. Higher yields can result in more effective land use planning and management, which will become

important as we continually try to feed more people with less space. Land that is saved from intensive agriculture could be use for conservation, which could improve the environment.
Some points of consideration for this study that may contribute to uncertainty in the results, is Flourish Farms, up until recently, did not weigh their fish. The method for sales included estimating fish length at approximately 12.7 cm long or plate size and selling the fish for an even five USD. Typical aquaculture studies meticulously weigh the protein produced and sell the fish by weight which gives very accurate production numbers, instead of the estimates used in this study. The farm also experienced a dramatic die-off during the 2014 year in which 491 fish died due to loss of electricity. In order to account for this die off, this study added these fish weights into the protein produced, even though this protein was not sold.
Additionally, many studies use the DM value of plant mass as a better indication of the actual production. DM does not include the water accumulated while growing, and therefore has a greater consistency than WM. As water has no nutritional components, it is not ideal to use the water weight within the product as part of the production. However, since the data for this study were taken from 2014 Flourish Farms had already weighed their products before the viewing of the data and any alterations could occur. One recommendation for future data collections would be to have DM values for each product that the farm is selling, in order to have more accurate measure of the food produced. Another data collection recommendation would be to have consistency in the metrics that are being collected. Not all data points in all years had consistent utility readings or fish counts. Other helpful metrics would be daily water temperature readings, air temperature readings, and more precise recordings of equipment operation throughout the year.

One issue with comparing LCA results to other LCA literature studies is that rarely will the study boundaries reflect the same exact inclusions and exclusions. Each LCA is completed with individual goals, and therefore the studies can be difficult to compare equally as some studies will include more of the process than others. This is a concern for this study as some of the literature values, (e.g. Barbosa et al., 2014) used fewer production components than this study, while others (e.g., cradle to grave aquaculture studies) used more production and life cycle events than this study. Unfortunately, without completing a range of LCA studies compromising of various study boundaries this issue cannot be avoided.
LCAs will usually only compare if the two systems analyses were completed by the same researcher, so the variable for the study boundary will be consistent. In order to account for this discrepancy, the values for this study are primarily used for the farms benefit, and not as concrete comparative value. A confidence variation analysis could help to make the comparisons more effective.
Additionally, the allocation methods for this study could be improved since the economic production required some estimation in regards to fish weights and sales. A method involving resource requirements or mass for each subcategory of production may generate better allocation percentages and will be considered for future research. Ultimately, better systems information will quantitatively address hypotheses about the relative efficiencies of aquaponic vs. other alternative farming techniques.
Local year-round food production is becoming increasingly important to communities looking to have higher food security and food sovereignty, and aquaponics is a mechanism that communities can explore. LCAs can help individuals and communities evaluate if this food production system is the right fit for the goals they hope to achieve.

2.5 Conclusions
This study has shown that aquaponics possesses certain environmental benefits as compared to other agriculture systems. If applied on a larger scale, aquaponics could have significant positive environmental impacts on the food system. This production system also shows promise in international development to increase access to affordable protein when there are limited options available. This research demonstrated that there may be ways to produce high quality protein and produce, that has potential to be less environmentally wasteful and costly than traditional agriculture, hydroponics and aquaculture. Further investigation and implementation of alternative food systems could be a step in increasing local food production, and shifting away from the industrial global food market.

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Flourish Farms Delivery Locations
1. The Growhaus 4751 York Street, Denver CO 80216
2. Blue Moon Brewing Company 3750 Chestnut Place, Denver CO 80216
3. Comida at the Source 3350 Brighton Boulevard #105, Denver CO 80216
4. Mondo Market 3350 Brighton Boulevard #115, Denver CO 80216
5. The Populist 3163 Larimer Street, Denver CO 80205
6. The Preservery 3040 Blake Street #101, Denver CO 80205
7. Nocturne 1330 27th Street, Denver CO 80205
8. Aloy Thai 2134 Larimer St., Denver CO 80205
9. Vesta Dipping Grill 1822 Black Street, Denver CO 80202
10. Cholon Modem Asian Bistro- 1555 Blake Street #101, Denver CO 80202
11. Squeaky Bean- 1500 Wynkoop Street #101, Devner CO 80202
12. Central Bistro 1691 Central Street, Denver CO 80211
13. Western Daughters Butcher Shoppe 3326 Tejon Street, Denver CO 80211
14. Linger 2030 West 30th Avenue, Denver CO 80211
15. St. Kilians Cheese Shop 3211 Lowell Blvd, Denver CO 80211
16. Charcoal Restaurant 43 West 9th Avenue, Denver CO 80204
17. Marczyks Fine Foods (17th) 770 East 17th Avenue, Denver CO 80203
18. Thump Coffee 1201 East 13th Avenue, Denver CO 80218
19. SAME Cafe 2023 East Colfax Avenue, Denver CO 80218
20. Denver Zoo 300 Steele St., Denver CO 80205
21. Marczyks Fine Foods (Colfax) 5100 East Colfax Avenue, Denver CO 80220
22. The Plimoth 2335 East 28th Avenue, Denver CO 80205
23. GrowHaus 4751 York Street, Denver CO 80216

Flourish Farms Produce Production 2014
Row Labels Values Sum of Units harvested Sum of Harvested weight (oz) Average of Average weight/unit (oz)
Baby Greens mix 166 367 2.58
Basil Genovese 48 104 2.17
Bok choy tatsoi Bright Lights Rainbow Swiss 1148 2433.12 2.631034483
Chard 93 365.25 1.67
Celery Utah Chinese cabbage 55 80 1.45
Michihili 52 189 3.77
Cilantro Calypso 327 633.2 2.145833333
Collard Greens 23 84 3.65
Collards Vates 250 447.25 2.02125
Common mint Dwarf blue curled 103 260 3.14
kale 142 370.25 3.266
Endive Salad King 51 122.45 2.4
Flat-leaf parsley Grand Rapids lettuce 22 143
Green Star 2549 9393.69 3.373069307
Green Bibb Lettuce Green bibb lettuce 3 12 4
Buttercrunch Green Bibb Lettuce 522 1057.75 2.484615385
Flandria Green bibb lettuce 679 2549.19 3.789
Rex Green butterhead 5129 16612.90167 3.439322034
lettuce Green romaine 133 561 3.428
Claremont Green romaine Green 364 1395.9 3.574285714
Forest Green romaine 26 179 6.88
Ridgeline 16 86 5.38
Helvius romaine 24 126 5.25
Hybrid kale 105 298.75 2.9425
Kale Starbor 1514 3455.5 2.812826087
Mache com salad 27 92 3.41
Mustard Greens 194.5 336 2.97

New Red Fire
Parris Island romaine 8089 27568.71 3.433843416
Purple mizuna 473 1490.8 3.541764706
Purslane Red Gruner 42 86.6 2.19
Red Bibb Lettuce Cherokee 40 209.5
Red bibb lettuce Red Cross 46 171 3.925
Red bibb lettuce Skyphos 76 312 4.156666667
Red butterhead lettuce 16 64 4
Red Giant mustard 252 1121.875 4.0375
Red leaf lettuce Lollo Rossa Red Lettuce Cherokee 23 132.75
Red oakleaf lettuce Malawi 97 309 3.245
Red oakleaf lettuce Oscarde 669 1567.885 2.212
Red romaine Garnet Rose 28 96 3.43
Red romaine Outredgeous 73 251 3.5825
Red romaine Rouge d'Hiver 26 105.5 4.06
Red Russian kale 2564 6838.665 2.891392405
Red Summer Crisp lettuce Cherokee 849 2519.24 2.985151515
Red velvet lettuce 42 144 3.145
Redbor kale 7 14.5 2.07
Red-veined sorrel 203 402.5 2.504285714
Ridgeline Romaine 48 207.75 4.63
Romaine Coastal Star 80 352 4.383333333
Romaine lettuce Freckles 24 94 3.92
Romaine Red Rosie 20 24 1.2
Romaine Ridgeline 130 758.1 3.345
Romaine Sparx 175 769.24 2.39
Swiss chard Bright Lights rainbow 1756 5139.6 3.355769231
Orange Swiss chard white 56 286 5.105
Tuscan kale 828 2289.25 3.033214286
Watercress 56 144 2.57
Grand Total 30553.5 95223.66667 3.240651751

Flourish Farms Integrated Pest Management Use 2014
Row Labels Sum of Preparation (mL/L)
Aqua-C 4750
Azamax 32
Azatrol 214
biomin Ca 6
Botanigaurd 91.5
Bti 2392
M-pede 294
Serenade 756
Grand Total 8535.5

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DISS_surname Hollmann
DISS_fname Rebecca
DISS_middle Elizabeth
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DISS_description page_count 80 masters external_id http:dissertations.umi.comucdenver:10813 apply_for_copyright no
DISS_title An Aquaponics Life Cycle Assessment: Evaluating an Innovative Method for Growing Local Lettuce and Fish
DISS_comp_date 2017
DISS_accept_date 01/01/2017
DISS_degree M.S.
DISS_inst_code 0765
DISS_inst_name University of Colorado Denver
DISS_inst_contact Biology
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DISS_cat_code 0473
DISS_cat_desc Agriculture
Agriculture engineering
DISS_keyword Aquaponics, Energy, Greenhouse Gas, Life Cycle Assessment, Sustainability, Water
DISS_language en
DISS_para In most states, only one to two percent of the food consumed comes from a source within one hundred miles. The transition of food production to an industrialized global system has increased the use of artificial fertilizers, pesticides, and fossil-fuels, which negatively affects the environment, human health, and local economies. Actively promoting, optimizing, and investing in local food systems can reduce society’s reliance on industrial food production. Local food systems will become increasingly important due to the projected decreases in food production from climate change, the increasing demand for food due to population growth, and the nutrient pollution from current agriculture methods. Local food production benefits include increased food security and sovereignty, improving local economies, supplementary nutrition, preservation of genetic diversity, and fostering communities. The current study is a life cycle assessment (LCA) of a local food production system known as aquaponics. Aquaponics combines aquaculture and hydroponics in a recirculating engineered ecosystem using minimal resources and generating negligible waste. This research evaluated the global warming potential (GWP), energy use (EU), and water dependency (WD) of a local aquaponics system. These values where then compared with literature studies of traditional agriculture, hydroponics, and aquaculture. The LCA found that aquaponics yielded 22.02 kg wet mass (WM)/m2 of lettuce production, or 560% higher than traditional soil crop yield of 3.90 kg WM/m2 where hydroponics had the highest yield of 41.00 kg (WM)/m2. Aquaponics had a lower WD than traditional agriculture, 0.06 m3/kg to 0.25 m3/kg respectively, but a higher WD than hydroponics at 0.02 m3/kg. The EU for aquaponics was 10.58 mJ/kg, nine times lower than hydroponics at 90.00 mJ/kg of lettuce, but higher than traditional agriculture records of 1.10 mJ/kg. Aquaponics had a GWP of 8.50 kg CO2 equivalency per kilogram of fish production, and 4.45 kg CO2 e/kg for lettuce production. All other aquaculture systems had a higher EU and WD than aquaponics. Understanding the costs and benefits to aquaponics may lead to better system management and long-term decisions on the sustainability of aquaponics as an agricultural system.
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DISS_acceptance 1


ANAQUAPONICSLIFECYCLEASSESSMENT:EVALUATINGANINOVATIVEMETHOD FORGROWINGLOCALFISHANDLETTUCE by REBECCAELIZABETHHOLLMANN B.A.,UniversityofDenver,2013 Athesissubmittedtothe FacultyoftheGraduateSchoolofthe UniversityofColoradoDenverinpartialfulfillment oftherequirementsforthedegreeof MasterofScience IntegrativeBiology 2017




iii ThisthesisfortheMasterofSciencedegreeby RebeccaElizabethHollmann Hasbeenapprovedbythe DepartmentofIntegrativeBiology for GregCronin,Co-Chair JohnBrett,Co-Chair LaurelHartley May13 th ,2017


iv Hollmann,RebeccaElizabeth(M.S.,IntegrativeBiology) AnAquaponicsLifeCycleAssessment:EvaluatinganInnovativeMethodforGrowingLocal ProduceandProtein ThesisdirectedbyAssociateProfessorGregCronin,andAssociateProfessorJohnBrett ABSTRACT Inmoststates,onlyonetotwopercentofthefoodconsumedcomesfromasourcewithin onehundredmiles.Thetransitionoffoodproductiontoanindustrializedglobalsystemhas increasedtheuseofartificialfertilizers,pesticides,andfossil-fuels,whichnegativelyaffects theenvironment,humanhealth,andlocaleconomies.Activelypromoting,optimizing,and investinginlocalfoodsystemscanreducesocietysrelianceonindustrialfoodproduction. Localfoodsystemswillbecomeincreasinglyimportantduetotheprojecteddecreasesin foodproductionfromclimatechange,theincreasingdemandforfoodduetopopulation growth,andthenutrientpollutionfromcurrentagriculturemethods.Localfoodproduction benefitsincludeincreasedfoodsecurityandsovereignty,improvinglocaleconomies, supplementarynutrition,preservationofgeneticdiversity,andfosteringcommunities.The currentstudyisalifecycleassessment(LCA)ofalocalfoodproductionsystemknownas aquaponics.Aquaponicscombinesaquacultureandhydroponicsinarecirculatingengineered ecosystemusingminimalresourcesandgeneratingnegligiblewaste.Thisresearchevaluated theglobalwarmingpotential(GWP),energyuse(EU),andwaterdependency(WD)ofa localaquaponicssystem.Thesevalueswherethencomparedwithliteraturestudiesof traditionalagriculture,hydroponics,andaquaculture.TheLCAfoundthataquaponics yielded22.02kgwetmass(WM)/m 2 oflettuceproduction,or560%higherthantraditional soilcropyieldof3.90kgWM/m 2 wherehydroponicshadthehighestyieldof41.00kg (WM)/m 2 .AquaponicshadalowerWDthantraditionalagriculture,0.06m 3 /kgto0.25m 3 /kg


v respectively,butahigherWDthanhydroponicsat0.02m 3 /kg.TheEUforaquaponicswas 10.58mJ/kg,ninetimeslowerthanhydroponicsat90.00mJ/kgoflettuce,buthigherthan traditionalagriculturerecordsof1.10mJ/kg.AquaponicshadaGWPof8.50kgCO 2 equivalencyperkilogramoffishproduction,and4.45kgCO 2 e/kgforlettuceproduction.All otheraquaculturesystemshadahigherEUandWDthanaquaponics.Understandingthe costsandbenefitstoaquaponicsmayleadtobettersystemmanagementandlong-term decisionsonthesustainabilityofaquaponicsasanagriculturalsystem. Theformandcontentofthisabstractareapproved.Irecommenditspublication. Approved:GregCronin Approved:JohnBrett


vi AKNOWLEDGMENTS Thisthesiswouldnothavebeenpossiblewithoutthecollaborationandcontributions ofTawnyaandJDSawyer,ownersandCEOsofFlourishFarmsandColoradoAquaponics. Theirmeticulousattentiontodetail,recordkeeping,allowingmeaccesstotheirdatabase, andansweringmymanyquestionsisthefoundationofthisresearch.Ialsowouldliketo specificallythankMarielleDOnofrioforansweringmanyquestionsforme,findingspecific metricsandhelpingtogatherdata.MyadvisorsatUniversityofColoradoDenver,Dr.Greg CroninandDr.JohnBrett,havebeenendlesslyhelpfulinsupportingmyacademic development,mentoringmeandguidingmethroughthisthesis.Iwouldalsoliketothank mycommitteemembers,Dr.AlanVajdaandDr.LaurelHartley,forprovidingfeedbackand supportonthisthesis.ThankyoutoTamaraChernomordikforassistancewiththe GaBiV5.0 lifecycleassessmentsoftware,andguidanceonhowtoanalyzethedataonthissoftware. Also,animmensethankyoutoStephenFisher,PhD,whoassistedmeinthetheoretical framesetofmypaperandunderstandingtheLifeCycleAssessmentmethod.


vii TABLEOFCONTENTS CHAPTERS I. THERELEVANCEANDBACKGROUNDOFAQUAPONICSASAN ALTERNATIVEFOODSYSTEM. 1 1.1Introduction1 1.1.1Innerworkingsofaquaponics 1 1.1.2Historyofaquaponics3 1.1.3Aquaponicsystemtypes5 1.1.4ComparisonSystem...8 Hydroponics.. 8 Aquaculture... 9 ConventionalAgriculture.9 1.1.5Aquaponicproduction...10 1.1.6Aquaponicsystempotential... 11 1.2Theimportanceofalternativefoodsystems...14 1.2.1Climatechangethreateningfoodsecurity.14 1.2.2Thegrowingpopulation:waterandfooddemand.14 1.3Relevantbackground..16 1.3.1FlourishFarms...16 1.3.2ElyriaSwanseaneighborhood...19 1.4Lifecycleassessmentpractices..23 1.4.1Goalandscopedescription25 1.4.2Inventoryanalysisdescription...27 1.4.3Impactassessmentdescription... 27


viii 1.4.4Interpretationstagedescription.. 28 II.AQUAPONICSLIFECYCLEASSESSMENT29 2.1Introduction. 29 2.1.1Researchobjectives...30 2.1.2Studysite...30 2.2Methodology...32 2.2.1Goalandscope... 31 2.2.2Lifecycleinventory..36 2.2.3Lifecycleimpactassessment..43 Allocation.44 Totalresourceuse..44 Conversion44 2.3Results45 2.4Discussion..51 2.4.1Impactassessment.51 2.5Conclusion..58 REFERENCES...59 APPENDICES A. FlourishFarmsdeliverylocations..66 B. FlourishFarmsproduceproduction.67 C. FlourishFarmsintegratedpestmanagementusein2014..69


ix LISTOFTABLES TABLES 1. Nutrientwasteinalevee-stylecatfishpond 13 2. Pre-farm,on-farmandpost-farminclusionsandexclusionsintheLCA 34 3. LifecycleinventoryofFlourishFarms 35 4. ElectricaloperationalequipmentatFlourishFarms 38 5. NecessaryinfrastructureinFlourishFarmsaquaponicsystem 41 6. Thetotalglobalwarmingpotential(kgCO 2 e),energyuse(mJ)and waterdependency(m 3 )forFlourishFarmlettuceandtilapiaandhybrid stripedbassperkilogramin2014. 47 7. Comparisonofannuallanduse,waterdependency,andenergyusein aquaponics,hydroponicsandtraditionalagricultureforlettuce production. 49 8. Comparisonofglobalwarmingpotential,energyuse,andwater dependencyofvariousaquaculturesystemswithvaluesintermsofone kgproduced. 50


x LISTOFFIGURES FIGURES 1. Therecirculatingprinciplesoftheaquaponicslifecycle 3 2. TheUniversityoftheVirginIslandsdeepwaterculture(DWC) aquaponicfacility. 5 3. Mediabasedaquaponicsystem 6 4. Deepwaterculturerootsystem 7 5. Nutrientfilmtechnology(NFT)aquaponicsystem 8 6. LayoutofFlourishFarms 17 7. FlourishFarmsDWCandmainfishtank 18 8. BoundariesofDenver,Coloradozipcode80216 20 9. MajorToxicReleasingInventory(TRI)facilitiesandsuperfundsitesin ornexttozipcode80216 21 10. DenverCountyfooddesert 22 11. Phasesofalifecycleassessment 25 12. SystemboundaryfortheFlourishFarmLCA 33 13. Lifecycleassessmentprocessflowforfish 36 14. Lifecycleassessmentprocessflowforlettuce 37 15. SkrettingsPondLEfishfeedcomponents 39 16. TheGrowHausdeliveryroute 40 17. GlobalwarmingpotentialoffishproductionatFlourishFarms 46 18. GlobalwarmingpotentialoflettuceproductionatFlourishFarms 47 19. DistributionofglobalwarmingpotentialkgofCO 2 e/kgofproduction withinFlourishFarms. 48


xi ABBREVIATIONS CO 2 CarbonDioxide DM DryMass DWC Deep-WaterCulture EPA EnvironmentalProtectionAgency EU ElectricityUse GHG GreenhouseGas GWP GlobalWarmingPotential HSB Hybrid-stripedbass ILCD InternationalReferenceLifeCycleDataSystems IOS InternationalOrganizationforStandardization IPCC IntergovernmentalPanelonClimateChange IPM IntegratedPestManagement LCA LifeCycleAssessment LCIA LifeCycleInventoryAnalysis NFT NutrientFilmTechnology TRI ToxicReleasingInventory USDA UnitedStatesDepartmentofAgriculture WD WaterDependence WM WetMass


1 CHAPTERI THERELEVANCEANDBACKGROUNDOFAQUAPONICS 1.1Introduction 1.1.1Innerworkingsofaquaponics Thisresearchassessesefficiencyandoutputofacommercialaquaponicssystemknown asFlourishFarmsinDenver,Colorado.Theglobalfoodproductionsystemisprojectedto declineincropoutputduetoclimatechange(Nelson,2009),andpopulationgrowthwill continuetoexceedthecarryingcapacityoftheplanet(Barrett&Odum,2000),whichwill leadtoagreaterpercentageoftheworldspopulationreceivinginadequatenutritionona dailybasis.Currentagriculturalmethodsareaprimarycontributortoclimatechangeand environmentaldegradation.Ifcurrentagricultureisfurtherinvestedinandexpandedinorder tomeettheincreasingdemand,environmentalcollapseisexpected(Edenhogeretal., 2014). Alternativefoodproductionsystems,suchasorganic,hydroponics,aquaculture,urban gardening,andlocalfoodproductionofferasolutiontosteerawayfromtheglobalfood system,andtowardshealthierandmoresustainablecropoutputwhilerevitalizingthe environment.Aquaponicsisapromisingsystemdesigntoproduceproteinandvegetables usingminimalresourcesandwasteproduction.Thistechnologyisintheearlystagesof developmentworldwidewithfewcommercialsystems.CompletingaLifeCycleAssessment (LCA)ononeofthewellfoundedcommercialsystemsinDenverwillelucidatetheresource use,globalwarmingpotentialandwasteproductionofthisaquaponicssystem. Understandingthesystemvaluemayleadtobettersystemmanagement,andlong-term decisionsontheviabilityofaquaponicsasapotentialforyear-roundlocalfoodproductionin temperateclimates.


2 Aquaponicfarmingisapromisingtechnologyforlocal,sustainablefoodproduction. Aquaponicscombinesaquaculture( e.g. aquaticanimalfarming)andhydroponics ( e.g. soillesssystemsforcropproduction)inarecirculatingengineeredecosystemto simultaneouslyproducevegetablesandprotein.Aquaponicssystemshaveahighyieldand canannuallyproduce41.5kg/m 3 oftilapiaand59.6kg/m 2 oftomatoesina1.2mwide,0.33m deepand0.86mlongtankwith4plantplots(McMurtryetal.,1997).Aquaponicfarms utilizetheeffluentfromaquaticanimalsrichinammoniumbycirculatingittonitrifying rhizobacteriatofertilizehydroponicvegetables. Nitrosomona speciesoxidizethetoxic ammonia(NH 3 )intonitrite,andthen Nitrospira bacteriaconvertnitrite(NO 2 -) intonitrate (NO 3 -),whichislessharmfultothefish,butfertilizestheplants.Thewater,nowcleansedof ammonia,nitrates,andothernutrientsafterflowingthroughthebacteriamatrixandroot system,circulatesbacktotheaquaculturesubsystem(McMurtyetal., 1997)(Fig1.).


3 Figure1 .Therecirculatingprinciplesoftheaquaponicslifecycle.Thefishexcretewaste productswhichareturnedintonitratesfrombacteriaspeciessuchas Nistrospirasp. Theroot systemisthenabletoabsorbthesenutrients,andquicklygrowintoaharvestableproduct. Thefisharethensuppliedwithcleanwaterandareanotherharvestableproductwithintime (Engle,2013). 1.1.2HistoryofAquaponic Althoughthetermaquaponicswascoinedinthe1970s,thescienceofaquaponics developedlongago.OneoftheearliestwastheAztecagriculturalislandsknownas chinampasthatwouldfloatontopofshallowlakesabout1,000yearsago(Crossley,2004). Aztecswouldfertilizetheislandswithnutrientrichmudfromnearbycanals.Additionally,in SouthChina,ThailandandIndonesiagrewfishinricefieldsapproximately1,500yearsago


4 (Coche,1967).Thispolyculturepracticestillexiststodayashundredsofthousandsof hectaresofricefieldsarestockedwithfish(Coche,1967). Developmentofcontemporaryaquaponicsystemsispracticedinwarmandtemperate climateswithmanyvariationsinsystemconstructionandcultivatedspecies(Bainbridge, 2012).Modernaquaponicswasfirstinfluencedbyresearchersstudyingrecirculating aquaculturesystemswhowerelookingforsolutionstoeliminateaccumulationsofnitrogen (Loveetal.,2014).Oneofthesolutionsresearchersidentifiedwastocombineasoillessplant systemintotheaquaculturesystemasawayofwithdrawingthenitrogencompoundsoutof thewater.Present-daysystemsnowrelyonmanyhydroponicgrowingmethods,suchasuse ofagreenhouse,andsimilargrowingtechnologies. OneofthemajorrevolutionstotheaquaponicsindustrywastheworkofDr.James Rakocy,knowncolloquiallyastheFatherofAquaponics.Hebeganfurtherinvestigationof aquaponicssystemswhileworkingonhisPhDatAuburnUniversity,graduatingwitha degreeinaquaculturein1980.HethendevelopedanaquaponicsfacilityattheUniversityof theVirginIslands(UVI).Thesystemstartedsmall,butcontinuedtoexpandintoa commercialsystemwhichcontainssixhydroponictankswithagrowingareaof2,303ft 2 and fourfishrearingtankscontaining7798litersofwatereach.In1999Dr.Rakocystarteda trainingprogramwithstudentsfromallovertheUnitesStatesandterritories.Thesystemhas becomeanimportanttoolintrainingstudentsandeducatorsaboutaquaponicsalloverthe world,andhasproventobesuccessfulinproducinghighquantitiesoffishandvegetables (Rakocy,2012).Dr.RakocyandDr.Lennardnowteachacommercialaquaponicsworkshop atUVItwotimesayear,whichhasbeeninstrumentalforthedevelopmentoflargescale systemsworldwide(Rakocy,2012;Fig.2).


5 Figure2. TheUniversityoftheVirginIslandsDWCaquaponicfacility.UVIhasoneofthe bestestablishedanddeepwatercultureaquaponicsystemswheretheyofferintensivetraining course(Rakocy,2012). 1.1.3Aquaponicsystemtypes Therearethreemaintypesofaquaponicsystemconstructions:media-basedgrowing, deep-waterculture(DWC),andnutrientfilmtechnology(NFT).Atminimum,asystemwill havesomeformofatankcontainingaquaticspecies,growbeds,andapump.Mostsystems containasolidsremovalsystem;however,inmedia-basedsystemsscudsand/orwormscan beaddedasaneffectivesolidsremovalmechanism.Withinthemedia-basedgrowingthere areseveraldifferentdesignsthatcanbeputintoplace.Therearebasicfloodanddrain systems,designswithsumptanks,constantheightonepumpsystems,andevensystems usingbarrels( Bernstein,2011 ;Lennard&Leonard,2006).Thereareprosandconstoadding sumptankstoasystem.Sumptanksaresecondtankskeptwithoutfish,wherewaterwill continuouslydrainfromthegrowbedsbeforerecirculation.Designswithoutasumpare typicallymuchmoresimpleandeasytoconstruct,howeverthechangingwaterlevelscan addstresstothefish.Designswithasumptankaremoredifficulttoconstruct,butwillkeep


6 thewaterinthefishtankatacontinuouslevel,whichisidealforthefish(Bernstein,2011; Fig.3). Figure3. Mediabasedaquaponicsystemwithsumptank.Infarmsusingmedia,thewater willfloodanddrainthesystem.Someadvantagesforthemediabasedsolutionaregrowing morerootintensivecrops,solidentrapment,andsomesystemsusedetrivoresinthemediaas well(Lovatelli,2015). Theseedsinmediabasedsystemscanbeplanteddirectlyintothemedia,ortransplanted fromnurseries.Themediaandrootmatrixisanefficientsolidsfilter,andnootherremoval systemisneeded.Mediabasedsystemsalsoprovideidealgrowthenvironmentsforthe necessarybacteria.Anotheradvantagetoamediabasedsystemisthisdesignallowsthe greatestflexibilityforwhatcropscanbegrown. DWCsystemsusewaterfilledbedswithfloatingraftswhichsupporttheshootsabovethe waterline,astherootshangintothewater.Therootshangintothewaterdirectlyandthe bacteriacanusuallygrowontotheseextensiverootsystemswithoutfurtherassistance(Fig.


7 4).Insomefarms,thebacterialwillcultivatewithinthesolidsremovalanddentrification tanksaswell. Figure4. Deepwaterculturerootsystem.InDWCsystems,therootshanglooseintothe watercultureonfloatingrafts( DWCaquaponicfarmsaremorelimitedinwhattheycangrow,anddorequirefurther solidsfiltration.However,thesesystemsaretypicallyusedincommercialaquaponics facilitiesastheyarerelativelyinexpensivetosetupcomparedtoothersystemtypes,andthe cropsareconsiderablymoreeasytoharvestthaninamediabasedsystem(Bernstein,2011). Thelasttypeofsystem,NFT,usescondensedchannelsintowhichnurseryplantsare transplanted,whereamoreconcentratedstreamofwaterflowsthroughtherootsystems(Fig. 5).Thesesystemslookcharacteristicallymorelikehydroponicsystems.Theyoffermanyof thesameadvantagesanddisadvantagesofDWCsystems,inthatthecropsareeasyto


8 harvest,butthevarietiesthatcanbesuccessfullygrownarelimited(Bernstein,2011).This systemisprimarilyusedforleafygreensandherbs,asotherplantsdevelopextensiveroot systemsthatcaneasilyblockthechannels(St.Charles,2013). Figure5. Nutrientfilmtechnologyaquaponicsystem.NFTsystemsareoneofthemost commongrowingpracticesforhydroponicsystems,andthetechniquehascarriedoverinto aquaponics(Lovatelli,2015). 1.1.4ComparisonSystems Hydroponics. ThewordhydroponicsisderivedfromtheGreekrootsof hydro and ponos ,meaningworkingwater.Thehistoryofhydroponicsdatesbackto1929withDr. WilliamGerichfromtheUniversityofCalifornia(Loveetal.,2014).Inessence,hydroponic farmingisthescienceofgrowingplantswithouttheuseofsoil,inaliquidculture (Wignarjah,1995).Inhydroponicsystems,nutrientsolutions,mainlychemicalsalts,are addedtotheculturethatcontainsalltheessentialelementsneededbytheplantforitsnormal growthanddevelopment.Likeaquaponics,hydroponicscanbedevelopedwithseveral differentdesigns,includingNFTasoneofthemostpopulartechniquesforproducingleafy greens.However,mediabasedoptionsarestillusedtosupportalargervarietyofvegetables. Manyhydroponicsystemsareoperatedincontrolledenvironmentfacilitiesinorderto


9 increasetheyieldofthecrops.Additionally,sincetherootscaneasilyobtainthenecessary nutrientsinthesyntheticliquidcultures,theyieldisoftenmuchhigherthanconventional agriculture(Loveetal.,2014).Hydroponicsalsorecirculatesthewaterinordertomore sustainablynurtureandsupportplantproduction. Aquaculture. Aquacultureisthebreeding,rearingandharvestingofplantsandanimals withinawaterenvironment,whichcanrangefromponds,rivers,lakesandtheocean. Aquaculturehasalonghistoryofpractice,datingbackto2,500B.C.inChina,withthe cultivationofcommoncarp( Cyprinuscarpio )(Rabanal,1988).Near500B.C.FanLaiwrote amonographnamesTheClassicofFishCulture,whichisthefirstknowndescriptionof aquaculturepractices.Aquaculturecanalsobeknownasaquafarming,whichimplies interventioninthenaturalrearingprocessinordertoenhanceproduction.Thesepractices canrangefromstocking,feeding,andprotectionfrompredators(FAO,2011).Todaywith thedeclineofwildfishpopulations,aquacultureisamassiveindustrywithoveronehalfof consumedfishproductssuppliedbyaquaculturefacilities(StanfordUniversity,2009). ConventionalAgriculture .Themodernindustrialagriculturalpracticehashistorically beendefinedasgrowingcropswithsoil,withoutcover,andtreatingthecropswithirrigation, nutrients,pesticidesandherbicides(Barbosaetal.,2015).Thesetraditionalagricultural techniquesbecamepopularizedinthe20 th century,whichwasknownastheGreen Revolution(Hazell,2009).Withthesetechnologies,conventionalagricultureproducesgreat yields,butalsohasintensiveresourcerequirements.Conventionalagricultureisoften juxtaposedtoorganicfarming,whichdoesnotpermittheuseofsyntheticfertilizers, pesticides,geneticallymodifiedorganisms,orionizingradiationorsewagesludge(USDA, 2016).Thesestandardsweredevelopedinthelate19 th centuryincentralEuropeandAsia.


10 1.1.4AquaponicProduction Aquaponicstechnologieshaverecordsofsuccessfullyraisingmanydifferenttypesoffish including:severalvarietiesandhybridsoftilapiasuchasredtilapia( Oreochromisspp )and Niletilapia( Ocheochromisniloticus), andmanyotherspeciessuchasyellowperch( Perca flavescens), catfish( Ictaluruspunctatus), stripedbass( Moronesaxatilis ),rainbowtrout ( Oncorhynchusmykiss ),Arcticchar( Salvelinus alpinus ),barramundi( Latescalcarifer ), Murraycod( Maccullochellapeeliipeelii), commonandkoicarp( Cyprinusspp ),goldfish ( Carassiusauratus )andcrustaceanssuchasredclawcrayfish( Cheraxquadricarinatus ), Louisianacrayfish( Procambarusclarkii), andgiantfreshwaterprawn( Macrobrachium rosenbergii )(Bainbridge,2013). Thereareover60speciesofplantssuccessfullygrownusingaquaponics,andmanymore inhomehobbysystems(Bainbridge,2013).Leafycrops,suchaskale,romaineandbib lettuce,havetypicallybeenthemostsuccessfulandcanbegrowninanyoftheabovesystem designs.Inorderfortheseplantstogrow,theymustabsorbcarbonandoxygenfromtheair, andobtainwater,macroandmicronutrientsandlight.Inaddition,plantsrequirethree primarymacronutrients(nitrogen,phosphorus,andpotassium),threesecondary macronutrients(calcium,sulfur,andmagnesium)andeightmicronutrients(boron,chlorine, manganese,iron,zinc,copper,molybdenumandnickel)togrow(Barker&Pilbeam,2007). Inaquaponics,allofthemacronutrientsareobtainedfromthefisheffluentthathasbroken downandgonethroughnitrification.However,somestudieshaveshownthatthe concentrationsofnutrientsarenotsustainedovertimeifanon-supplementedfishdietisused (Somervilleetal., 2014;Al-Hafedhetal., 2008).Somestudieshaveindicatedthatpotassium, iron,andcalciumneedtobeincorporatedwithinthesysteminordertohavecontinued


11 healthyplantgrowth(Sommervilleetal., 2014;McMurty,1997).Thesenutrientsareoften addedassaltsareusedtobalancethepH( e.g., potassiumhydroxideandcalciumhydroxide). 1.1.5AquaponicSystemPotential Asdevelopmentofaquaponicsystemsspreads,manymoreindividualsandcompanies arerealizingthebenefitsthataquaponicscanoffer,bothenvironmentallyandeconomically. Itisestimatedthataquaponicsusesabout10%ofthewatercomparedtosoilcrops (Somervilleetal., 2014;Lennard&Leonard,2006).Waterinsoilcropsislostfrom evaporation,transpiration,percolationinthesubsoil,runoffandweedgrowth(Somervilleet al., 2014)Wateruseisataminimuminaquaponicsystemsontheotherhand,andmayhave onlya1.4%dailywaterreplacement(Al-Hafedhetal.,2008).Theonlywaterlossisthrough cropgrowth,transpirationthroughleaves,andnegligibleevaporationfromthesoil-less media.Becauseofthis,thepotentialforaquaponicswherewaterdemandishighor expensiveshouldbefurtherexplored(Summervilleetal., 2014). Inmostaquaponicsystems,artificialfertilizersarenotused,whichreduces environmentalpollutantsandsignificantlyreducescostsforthefarmoperations.Becausethe cropsareallgrownsoilfree,therearenosoil-bornediseases,noweedsandnotilling required.Manyaquaponicfacilitiesareeitherconstructedingreenhouseorintropical climates,andthereforecanproducefoodyearroundandinplaceswithpoorsoilquality. Oneoftheothermajorbenefitsaquaponicsprovidesislowoutputofwasteproducts, whereashydroponics,aquaculture,andconventionalagriculturecanallhavesignificant wasteproduction.Foreitherclosedoropenhydroponicsystemsthenutrientsolutions becomeoutofbalanceandunusable,andthesystemsmustbeflushedaboutonceevery30 days(Storey,2016).Thewastewaterisnormallydisposedofdownintodrains,andisfiltered bythecityswatertreatmentfacilities(Quintaetal., 2013).Inthelongrun,thissolutionmay


12 notbeefficientasfacilitiesoftenrequiremoremoneytodealwithpollutionloadsthatthe hydroponicfacilitiesareproducing,andinsomecasesmaynotevenbeabletoextractallof theexcessnutrients.Dumpingintowatersourcesishighlyregulated,withpressuresfromthe EnvironmentalProtectionAgency(EPA),UnitedStatesDepartmentofAgriculture(USDA), NaturalResourcesConservationService,andStateandRegionalWaterQualityControl boards.Becauseofthis,manygrowersfindithardtolegallydisposeofthiswaterwithout violatingtheCleanWaterAct(CleanWaterAct,1972).TheCleanWaterActmaintainsthat itisunlawfultodischargepollutantsintowaterunlessapermitisobtained.Themain componentsofhydroponicwastearephosphatesandnitrates,whichcanleadtoover nourishmentinbodiesofwaterinaprocesscalledeutrophication.Thiswillresultinalgal blooms,whichcandeoxygenatethewaterandreleasetoxins,oftenkillingthefloraandfauna within.Wetlandbasedwastewatertreatmentoptionsarebeingresearchedasasustainable solutiontonaturallyfilterthewater(Quintaetal., 2013). Inordertomaximizeaquacultureproduction,efficientwasteandsolidcollectionmethods areimportant.Ammoniaistheprimarywasteproductexcretedbyfishacrossthegillsas ammoniagas(Rakocy,1992).Un-ionizedammoniaisextremelytoxictofishandcancause tissuedamageatconcentrationsaslowas0.06ppm(Rakocy,1992).998gramsofammonia areproducedfrom45kilogramsoffishfeed,andthereforethefiltersinaquaculturearea crucialcomponentofproduction(Rakocy,1992).Fisheffluentischaracteristicallyhighin nitrogen,phosphorusandsulfatedependingonthefishfeedinuse.Inaleveestylecatfish ponds,nutrientinputandoutputweremeasured(Tucker,2009).Theexcretednutrient contentswereveryhighinexcessnutrientswithnitrogenaveraging448kg/haand phosphorusaveraging90kg/ha(Table1).


13 Table1. NutrientwasteinaLevee-stylecatfishpond.Theaboveconcentrationswere measured,whichdemonstratesthehighnutrientwastegeneratedthroughaquacultural production(Tucker,2009). NitrogenPhosphorus Infeed(kg/ha) 560 112 Excreted(kg/ha) 448 90 ManyaquaculturefacilitiesdisposeoftheirwastewaterdirectlyintowatersoftheUnited States,andthereforetheEPAhassetguidelinesandregulationsonwhatcanbedisposedof (EPA,2012).Therearecurrentlynonumericlimits,butinsteadrequiringbestmanagement practicestocontrolthedischarge(EPA,2016). Traditionalagriculturepresentsoneofthelargestwaterandnutrientconcerns.World agriculturerequiresapproximately70%ofthefreshwaterwithdrawnperyear(Pimentel, 2004).Forexample,soybeansrequire2,000litersofwaterperkilogramofcropoutput,rice requires1,600litersperkilogram,andwheatrequires900litersofwaterperkilogramof output(Pimentel,2004).Researchalsoprojectsthatweareseverelyoverfertilizingcrops.A studyoncornfertilizationshowedacomparisonbetweenNorthChinaandUnitedStates fertilizationrates.Chinainput588kilogramsofnitrogen/hectareayear,and92kilogramsof phosphorusperhectareayearwithanoutputof8,500kilogramsofcorn/hectareayear, whiletheUSinput93kilogramsofnitrogen/hectareand14kilogramsofphosphorus/hectare withanoutputof8,200kilogramsofcorn/hectare(Vitousek,2009).Newsolutionsare neededtocombatboththenutrientdischargeproblemsassociatedwithhydroponics, aquaculture,andconventionalagriculture.


14 1.2TheImportanceofAlternativeFoodSystems 1.2.1Climatechangethreateningfoodsecurity Theglobalfoodsystemcontributes21%-23%oftotalCO 2 emissions,55%-60%oftotal CH 4 emissions,and65%-80%oftotalN 2 Oemissions(Edenhogeretal., 2014).In2014,the IntergovernmentalPanelonClimateChange(IPCC)reportedwithmediumconfidencethat theestimatedtemperatureincreasesof2Cormorewillnegativelyimpactproductionof majorcropsbyreducingproductionandincreasingenvironmentalthreatstocrops (Edenhogeretal., 2014). Currentagriculturalmethodsareextremelyvulnerabletopresent,andfuture,effectsof climatechange(Nelson,2009).Itispredictedthatclimatechangewillimpactagriculture biologicallytotheextentthattheconsequenceswillaffecthumanhealth.Variationin precipitationmayresultinshort-termcropfailures,andlong-termproductiondecline. Decreasedcropsyieldswillinturneffectproduction,consumptionandprices,whichwill likelyreducepercapitacalorieconsumption,andincreasechildmalnutrition(Nelson,2009). Itisprojectedthatby2050childmalnutritionwillriseby20%duetothedecreaseincalorie production(Nelson2009).Changesindeathratefrequencywillalsoinfluencethehuman populationsize. 1.2.2Thegrowingpopulation:waterandfooddemand Oneofthemajorproblemsfacingfuturefoodproducersishowtoincreaseyieldsforthe growingpopulation,whilesimultaneouslyusinglessland.Thehumanpopulationcounton November2016hasreached7.4billionpeople,withanexponentialprojectedgrowthforthe next100years(USCensus,2016).Thefuturepopulationgrowthislargelydependentonthe reproductiveanddeathlevelswithinthenext40years(Cleland,2013).In2100,the populationestimatesrangewithlowprojectionsof6.2billiontohighprojectionsof15.6+


15 billion;however,iffertilitylevelsremainthesameworldwideastheywerein2005-2010, thenthepopulationwouldexceed25billion(UnitedNations,2015).Despitetheselarge rangesofestimates,manyexpertshavepredictedthatpopulationincreasewillleveloffat about10billionwhichhasbeenpredictedastheearthscarryingcapacity(Cleland,2013; Barret&Odum,2000).Carryingcapacityisdefinedasthepopulationsizetheworldcan supportwithoutdamagingnatural,cultural,andsocialenvironmentandleavingfuture carryingcapacitiesintact(Aberneth,2001;Barrett&Odum2000).ThomasMalthusin1798 discussedtheseprinciplesinAnEssayonthePrinciplesofPopulationwhichdescribes howhumanpopulationgrowthisexponential,whereasnaturalresourcesgrowarithmetically. Fromthiswecandeducethatthepopulationwillatsomepointbeunabletoproduceenough foodtosupportsurvival(Barrett&Odum,2000).Thelong-termsustainabilityoftheearths humanpopulationdependsonhowcountrieshandlehumanreproductionstrategies,andthe everpressingissueofhowtoproducelargerquantitiesoffoodusingfewerresources. Eventhepopulationgrowthwithinthenext40yearswillhavemajoreffectsontheglobal foodsupplychainastherewillbeapproximately2billionmoremouthstofeed.Thedemand forfoodduringthisperiodispredictedtoincreaseby50%,comparedtothe30%population growth(Barrett&Odum2000).Misuseofsoils,over-grazing,aquiferdepletion,andlossof biodiversityandecosystemswillbesomeoftheinevitableconsequencesifwedonotact quickly.Aquaponicsmaybeaneffectivesolutiontooffsetsomeoftheseconcernsby providinghighvegetableandfishyieldusingnosoil,minimalspaceandwater,andincreased growthratescomparedtosoilcrops(Al-Hafedhetal.,2008).


16 1.3RelevantBackground 1.3.1FlourishFarms ThislifecycleassessmentwasconductedatColoradoAquaponicsFlourishFarms,in Denver,Colorado.ThisaquaponicfarmislocatedwithintheGrowHaus,onYorkSt.and170,intheElyria-Swanseaneighborhood.TheGrowHausisinarepurposed1,858square metergreenhousefromthe1970s,whichfunctionsasanon-profitindoorfarm,marketplace andeducationalcenter.Theyaimtocreateacommunity-driven,neighborhood-basedfood systembyservingasahubforfooddistribution,production,educationandjobcreation ( Foodisproducedyear-roundattheGrowHauswiththreeseparatesustainableand innovativeindoorgrowingfarms:hydroponics,permacultureandaquaponics.Thescopeof thisstudywillconcentrateontheaquaponicfarmFlourishFarmswhichoccupies297 squaremeterswithintheGrowHaus(Fig.6).


17 Figure6 .SchematicofColoradoAquaponicsFlourishFarms.Theimagedepictsthe integrationofdeep-waterculture(DWC),nutrient-filmtechnology(NFT),andmediabeds forgrowingproduce(ImagesusedwithpermissionfromJDSawyer). FlourishFarmscontainsallthreetypesofaquaponicsystems(DWC,NFTandmedia beds)astheownersshowcasethevariousconstructiondesignsforaquaponicssystems.The farmusedatilapiaandkoicarpcombinationformanyyears,duetothesefishsresilience andfastgrowthratesevenunderhighstockingdensities(Fig.7).


18 A. B. Figure7. FlourishFarmsdeepwatercultureandmainfishtank.(A)DWCraftsystem.The imageshowsthefourraftbedsthatcarrytheleafygreensvegetableoutput.(B)Fish production.Thistankpicturedemonstratesthetilapiaandkoifishthatsupplythenutrientsfor thesystem( However,throughout2014and2015theyswitchedtostripedbass,recognizingagreater valueandpreferenceforthisfishintheircustomercore(TawynaSawyerpersonal communication,2015).Theyhavealsosuccessfullyraisedcatfishandbluegill.Since FlourishFarmsmovedintotheGrowHausin2012theyhavegrownhundredsofdifferent


19 varietiesofvegetablesandhavesoldover13,608kilogramsoffoodwithinaneightkilometer radius.Theyalsocontinuetodonate10%oftheircropstotheGrowHaus,contributingtothe localcommunity(TawynaSawyer,Personalcommunication2015). FlourishFarmswasfoundedin2009byownersandCEOsTawnyaandJDSawyer.The farmservesnotonlyasacommercialproductioncenter,butalsoasamodelsystemthathas beenmimickedinschools,communitybuildings,correctionalfacilities,andhomes.Aspart ofColoradoAquaponicsmission,theyprovideaquaponictraining,curriculum,consultation andsupportprogramsthatcanbedeliveredtoindividuals,schools,institutionsand communitieslookingtotakechargeoftheirownsustainablefarmingandfoodsecurity ( 1.3.2ElyriaSwanseaneighborhood OneoftheGrowHaussmainprioritiesistoprovidefreshproduceandproteintothe ElyriaSwanseaneighborhoodandzipcode80216inwhichtheyarelocated(Fig.8).


20 Figure8. BoundariesofDenver,Coloradozipcode80216.ThisareaincludestheElyria SwanseaneighborhoodaswellassectionsofNorthfield,andtheRiverNorthArtDistrict. ThewhitestarindicatestheapproximatelocationoftheGrowHauswithinthisneighborhood (GoogleMapData). TheElyeriaSwanseaneighborhoodwasestablishedin1880asaworkingclass communityandhaslongbeensurroundedwithindustrialbuildingsandtransportation infrastructure.Thisneighborhoodiswellknownforbeingthemostpollutedzipcodeinthe state(Fig.9).


21 Figure9. MajorToxicReleasingInventory(TRI)facilitiesandsuperfundsitesinornextto zipcode80216.SeeAppendixAforfulllistingofSitesandContaminants.Thereare8 Superfundsitesinthisarea,withthemosttoxicreleaseinthiszipcodehasanEPAHazard rankingof70.71(max100),andthetoptenTRIfacilitiesrelease132,342kilogramsoftoxic chemicalperyear(lastrecordedin2013).Intheabovemapthesearelabeled110,andthe otherbluesquaresindicatedotherreportingfacilitiesinthisarea(NIHTOXMAP,2013). Inthisneighborhoodthereareapproximately10,700residents,outofwhich36%livein povertywiththelowestaveragehouseholdincomeinthestateand34%areundertheageof 18(CranCommunicationsInc.,2015).Theresidentsherehavelonglackedaccessto healthy,affordablefood,andtheareaisclassifiedasafooddesertinaccordancewiththe USDAdefinition(Fig.10).


22 Figure10. DenverCountyfooddeserts.Theaboveshadedareasarethe19censustractareas thatareclassifiedasafooddesertbasedontheUSDAsdefinition(USDAData,Google EarthImage). Fooddesertisatermthathasbeenusedinpublichealthandacademiainorderto describethefoodinsecurityassociatedwithresidentsinageographicalareahavinglittle accesstohealthyfood.TheUSDAquantifiesthisasalow-incomecensustractareawherea substantialnumberorpercentileofresidentshavelowaccesstoasupermarketoragrocery store.LowincomeisdescribedasfittingtheeligibilityrequirementsoftheTreasury DepartmentsNewMarketTaxCreditprogram.Anareadescribedaslowaccessisfurther thanonemilefromasupermarketorgrocerystoreinanurbanarea,ortenmilesinarural area(Dutkoetal.,2012). Inordertocombatthisfoodinjustice,theGrowHausofferstheirweekly,year-roundfood boxatadiscountedpricefortheseresidents.Thefoodboxesincludelocalfreshfarmeggs, andfruitandvegetablesfromlocalandoftenorganicfarmers.Theyalsoincludeorganic leafygreensfromtheirownaquaponicsandhydroponicsystems.Eachweaklyboxalso


23 includesacomplexcarbohydrateofeitherfreshlybakedbreadortortillas ( Inadditiontosellingproduceandfreshfishtotheresidentsinthenearbyneighborhood, FlourishFarmssellsthemajorityofitsproducetotoprestaurantsinDowntownDenver,all withinfivemilesofthefarm(AppendixA).TheserestaurantsincludeThePopulist,The Plimoth,VestaDippingGrill,JaxFishHouse,ThumpCaf,SAMECaf,MondoMarketat theSourceandMarzycksFineFoods( 1.4LifeCycleAssessmentPractices Thisresearchinvestigatedtheenvironmentalsustainabilityandcosteffectivenessofan alternativeforproducinglocalfood.Althoughtherearemanyaquaponicsystemsin production,especiallyinthelastfewyears,littleresearchhasbeenconductedonthecost effectivenessorecologicalefficiencyofaquaponics.Inorderforaquaponicstobeconsidered asanalternativefoodsystemthisanalysisiscriticalandnecessaryinordertojustifylarge investmentandproduction. Oneofthemostwidelyusedtechniquestodeterminetheenvironmentalimpactsofa systemisaLifeCycleAssessment(LCA).LCAassessmentbeganinthe1960swhen scientistsconcernedwithfossilfueldepletionandnaturalresourcelosswereseekinga methodtoevaluateresourceconsumption(Svoboda,1995).AnLCAisdefinedasa systematicevaluationoftheenvironmentalaspectsofaproductslifecyclestages.These stagescanincludeacradletograveapproach,whichimpliesconsideringaproductslife fromrawmaterialacquisition,tomanufacturing,productassembly,maintenance,product disassemblyanddisposal(Akundi,2013).RebeccaBainbridgecompletedthefirstLCAofa temperateaquaponicsystemin2012,lookingatenvironmentalimplicationssuchasthe globalwarmingpotential,non-renewableenergyuse,eutrophicationpotential,acidification


24 potential,andwaterdependency.Thisreportisanimportantfirststep,butmanyquestions andvariablesremaintobetestedwhichthisstudyhopestoachieve. AnLCAfirstcompilesaninventoryofrelevantenergyandmaterialinput,aswellas releases.Thesecomponentsarethenevaluatedandforthepotentialimpactsoftheinputsand releases(InternationalOrganizationforStandardization,1997) Oncethisiscompleted,an improvementanalysiscanbeconductedinordertodetermineopportunitiestoreduceenergy, materialinputs,orenvironmentalimpactsateachstageofthelifecycle.LCAshaverecently takenonimportanceinenvironmentalpolicymaking,asglobalstakeholdersarebeginningto feelpressuretoreducetheirenvironmentalimpact(Goedkoopetal., 2013).Fromthe internationalconcern,theInternationalOrganizationforStandardization(ISO)created principlesandframeworkforvoluntary,consensus-based,LCAstandardizationsfor countriestofollowsothatstudiesacrossthatworldcanbecomparedtocombatglobal problems.LCAsprovidethequantitativedatafordiscussionandinitiativetotakeplacein ordertoreduceenvironmentalimpact. ThemethodsforconductinganISO14040LCAconsistoffourphases(ISO,2006;Fig. 11): 1.Thegoalandscopewilldefinethepurposeandsystem 2.Theinventoryanalysiswilllistthematerialsandenergeticinputs 3.Theimpactassessmentwillevaluatetheenvironmentaleffects 4.Theinterpretationstagewillconcludewithrecommendationsforimprovements.


25 Figure11 .PhasesofaLifeCycleAssessment.(ISO14040,1997). 1.4.1Goalandscopedescription ThefirststepofanLCAistodefinethegoalandscopeofthesystem.Thisstepincludes manyvariablesandquestionsthatmustbedeterminedbeforethestartoftheproject.There mustbeaclearreasonforexecutingtheLCA,aprecisedefinitionoftheproductandits functionalunit,thesystemboundaries,datarequirements,dataassumptions,intended audience,howtheresultswillbecommunicated,andhowapeerreviewwillbemade (Goedkoopetal., 2013).TherearemanydifferentapproachestocompletinganLCA dependingongoal,resources,anddataavailable.TherearethreedifferentordersofLCA analysis(Goedkoop etal 2013): I. Onlytheproductionofmaterialsandtransportandincluded II. Allprocessesduringthelifecycleareincludedbutthecapitalisexcluded


26 III. Allprocessesincludingthecapitalgoodsareincluded.Usuallythecapitalgoods aremodeledinafirstordermode,soonlytheproductionofmaterialsneededto producethecapitalgoodsareincluded. ManyLCAsdonotincludecapitalgoods,whichcanreducethedatarequirementsforthe analysis.Insomesystemscapitalcontributesupto30%oftheenvironmentalimpact,soit canbebeneficialtoincludethedataintheboundaries(Goedkoopetal., 2013).LCAscan alsodifferentiateonwhetheritincludestheentirescopeofenvironmentalimpactorfocusin onsingleissues,suchascarbonfootprintingorwaterfootprinting.Ingeneraltheimpact categoriesinclude(Goedkoopetal., 2013): Non-renewableresources(withandwithoutenergycontent) Renewableresources(withandwithoutenergycontent) Globalwarming(CO 2 equivalents) Acidification(kmolH+equivalents) Ozonelayerdepletion(kgCFC11equivalents) Photochemicaloxidantformation(kgethane-equivalents) Eutrophication(kmolN+equivalents) TheboundariesofanLCAalsoincludeestablishingthescopeoftheenvironmental issuesthatwillbereported,suchasgreenhousegases.GHGsareclassifiedintothree differentscopesbasedontheGHGProtocolCorporateStandard.Scope1emissionsare directlyfromsourcesthatareownedorcontrolledbythesystem,suchasvehicleemissions oremissionsfromchemicalproduction.Scope2emissionsareindirectemissionsfrom sourcesthatarepurchasedbythesystem,suchastheemissionsgeneratedfrompurchasing energy,wheretheemissionsoccuratthefacilitywheretheenergyisgenerated.Scope3 emissionsareadditionallyindirectemissionsthatarenotreportedinScope2,thatareinthe


27 valuechainofthereportingcompany,bothupstreamanddownstream.Scope3emissions includeextractionandproductionofpurchasedmaterials.LCAsoftwarehasScope3 emissionsdatabasesforallprocessesthatarereported. 1.4.2Inventoryanalysisdescription Theinventoryanalysisencompassesthetaskofcollectingthenecessarydatainorderto performtheLCA.Therearetwotypesofdata,foregrounddatawhichreferstodatathat describeaparticularproduct,andbackgrounddatawhicharedatafortheproductionof genericmaterials,energy,transport,andwastemanagement.Foregrounddatamustbe collectedfromthesystemitself,whereasLCAsoftware,suchas GaBiV5.0, containsthe necessarybackgrounddata,suchasthescope2and3emissionsofcertainprocesses.LCA softwarehelpstomanagedataandmodeltheLCAwithintheISOstandards. GaBiV5.0 has severaloptionsforcreatingprocessmapsandflowsandhasseveralanalyzingand interpretingselections( foregrounddatacollectioninordertogatherallrequiredinformation.Inordertogainthe backgrounddata,the GaBiV5.0 softwarehasadatabasecovering10,000processesinthe EcoInventandU.S.LCIdatabases(Goedkoopetal., 2013). 1.4.3Impactassessmentdescription ImpactassessmentofanLCAisananalysistodetermineenvironmentalimpacts throughoutaproductslifetime.Thisphaseisaimedatunderstandingandevaluatingthe significanceofimpactsoftheproductionsystem(Goedkoopetal., 2013).Inordertodothis incompliancewiththeISO,aclassificationandcharacterizationneedtotakeplace. GaBi V5.0 softwarehasmanyavailableimpactassessmentmethodologiesbuiltintoitsprogram thatcanbeuseddependingonthegoalandscopeofthesystem.Theresultswilltypically displaywhichinventoryitemsarecontributingtotheenvironmentalfactors,andtowhat


28 degree.Theimpactassessmentanalysiscanhavemanystages,including;allocation,total resourceusecalculations,librarydetermination,andconversions.Ifnecessary,allocations willbedeterminedbytheenduser.Librarydeterminationdependsonwhatsoftware databasesareavailable,andwhichelementstheenduseristryingtoanalyze.Conversions intothesamefunctionoutputunitaretypicallydonewithinthesoftware. 1.4.4Interpretationstagedescription TheinterpretationstageisdescribedbyISO14044asthenumberofcheckstotest whetherconclusionsareadequatelysupportedbythedata(2006).In GaBi V5.0 softwarethis existsasachecklistthatwillreviewrelevantissuesmentionedintheISOstandard.These existmainlyasuncertaintyintheanalysis,suchasvariationinthedata,correctnessofthe model,andincompletenessofthemodel.Oncetheseaspectsareevaluated,themodelcanbe lookedattoseeifanyhotspotsexist,orareasofconsumptionthatarecausinglarge environmentalimpact.Thesehotspotscanberecommendedforsystemimprovementdesign changesinordertoreduceenvironmentalimpact.Thisstagewillalsobeusedtocomparethe resultsofanLCAtoanotherapplicablesystemorproductinordertodiscernwhichsystem canhavemoreviabilityandlessenvironmentalimpactslong-term.


29 CHAPTERII AQUAPONICSLIFECYCLEASSESSMENT 2.1 Introduction ThisresearchassessedtheoperationalproductionandsustainabilitypotentialofColorado AquaponicscommercialsystemFlourishFarmslocatedinDenver,ColoradointheUnited States.Aquaponicfarmingisapromisingtechnologyforlocal,sustainablefoodproduction. Aquaponicscombinesaquacultureandhydroponicsinarecirculatingengineeredecosystem thatutilizestheeffluentfromaquaticanimalsrichinammoniumbycirculatingittonitrifying rhizobacteriatofertilizehydroponicvegetables. Nitrosomona speciesoxidizethetoxic ammonia(NH 3 )intonitrite,andthen Nitrospira bacteriaoxidizenitrite(NO 2 )intonitrate (NO 3 ),whichislessharmfultothefish,andanutrientfortheplants.Thewater,now strippedofmostammoniaandnitratesafterflowingthroughthebacteriamatrixandroot system,circulatesbacktotheaquaculturesubsystem(McMurtyetal.,1997)Thissystem designcanannuallyproduceupto41.5kg/m 3 oftilapiaand59.6kg/m 2 oftomatoesina1.2m wide,0.33mdeepand0.86mlongtankwith4plantplots(McMurtryetal.,1997). Theglobalfoodproductionsystemisprojectedtodeclineincropoutputduetoclimate change(Nelson,2009),andpopulationgrowthwillcontinuetoexceedthecarryingcapacity oftheplanet(Barrett&Odum,2000),whichwillleadtoagreaterpercentageoftheworlds populationreceivinginadequatenutritiononadailybasis.Currentagriculturalmethodsare someoftheprimarycontributorstoclimatechangeandenvironmentaldegradation,andif theyarefurtherexpandedtomeettheincreasingdemand,environmentalcollapseisexpected (Edenhogeretal.,2014). Inplaceofaglobalfoodproductionsystems,hydroponics,aquaculture,urbangardening, andlocalfoodproductionofferanalternatives,andaimforahealthierandmoresustainable


30 cropoutputwhilerevitalizingtheenvironment.Aquaponictechnologyisasystemdesigned toproduceproteinandvegetablesusingminimalresourcesandwasteproduction. Aquaponicsalsooffersasolutiontothedifficultiesofacquiringproteinlocallyand affordably.Onefourounceservingoftilapiaincorporates50%ofthedailyprotein requirementsformen,and60%forwomen(USDASR-21,2014).Thistechnologyisstill usedasanichefarmingmethodwithonly257systemsoutofthe809UnitedStatessystems surveyedin2014operatingonthecommercialscale,withallothersclassifiedasbackyardor hobbysystems(Loveetal.,2014).However,aquaponicsisarapidlygrowingfieldasover 600systemshavebeenbuiltintheUnitedStatesfrom2010to2013(Loveetal.,2014). CompletingaLifeCycleAssessmentononeofthewell-foundedcommercialsystemsin DenverwillelucidatetheWD,EUandGWPofthisaquaponicssystem. 2.1.1ResearchObjective Inordertofurtherexamineandassessaquaponicsasamethodtogrowhighqualityfood, weperformedanLCAonthecommercialaquaponicssysteminDenver,Colorado,which comparedtheGWP,WDandEUtoliteraturerecordingsofresourceuseinconventional agriculture,aquaculture,andhydroponics.Thisanalysiswillenabletheenduserstotakeinto accountwhereinefficienciesintheaquaponicprocessmayexist,andhowtoimprove operationsforamoresustainablesystem.Theliteraturecomparisonswillhelpthose interestedintheaquaponicfieldtounderstandthebenefitsandresourcerequirementsforthe system,incontrasttootheravailableoptions. 2.1.2StudySite TheLCAtookplaceatFlourishFarms,runbyColoradoAquaponics,withinthe GrowHaus.TheGrowHausisinahistoric1,858squaremeter greenhousewhichfunctionsas anon-profitindoorfarm,marketplaceandeducationalcenter.Theyaimtocreatea


31 community-driven,neighborhood-basedfoodsystembyservingasahubforfood distribution,production,education,andjobcreation( producedyear-roundattheGrowHauswiththreeseparatesustainableandinnovative growingfarms:hydroponics,permacultureandaquaponics.Thescopeofthisstudywill concentrateontheaquaponicfarmFlourishFarmswhichoccupies297square-meters withintheGrowHaus. FlourishFarmswasfoundedin2009byownersandCEOsTawnyaandJDSawyer.The farmservesasacommercialproductioncenterandasamodelsystemthathasbeen mimickedinschools,communitybuildings,correctionalfacilities,andhomes.Aspartof ColoradoAquaponicsmission,theyprovideaquaponictraining,curriculum,consultation andsupportprogramsthatcanbedeliveredtoindividuals,schools,institutionsand communitieslookingtotakechargeoftheirownsustainablefarmingandfoodsecurity ( Thefarmcontainsthreetypesofaquaponicsystems,deepwaterculture(DWC),nutrient filmtechnique(NFT)andmediabeds,astheownersshowcasethevariousconstruction designsforaquaponicssystems.FlourishFarmsusedatilapiaandkoicarpcombinationfor manyyears,duetotheirresilienceandrapidgrowthunderhighstockingdensities.However, theygraduallyswitchedtohybridstripedbass(HSB)in2014and2015,recognizingagreater valueandpreferenceforthisfishbytheircustomers(TawnyaSawyer,personal communication2015).Theyhavealsosuccessfullyraisedcatfishandbluegill.SinceFlourish FarmsmovedintotheGrowHausin2012,theyhavegrownhundredsofdifferentvarietiesof vegetablesandhavesoldover13,607kgoffoodwithinaneightkilometerradius.


32 2.2 Methodology TheLCAfollowstheISO14040/14044guidelines(ISO,2006)andisseparatedintofour sections:(1)goalandscopedefinitions;(2)inventoryanalysis;(3)impactassessmentand(4) interpretation(aspresentedintheResultsandDiscussionsectionofthispaper). 2.2.1Goalandscope ThisLCAisconsideredastreamlinedLCA,asseveralprocessesinacradle-to-grave analysiswereomittedforthisstudy.However,streamliningtheLCAprocessisanessential elementinthegoalandscopedefinition,asfewLCAsarefull-scaleduetotimeandcost constraints,accordingtoTodd&Curran(1999).Streamliningallowsthestudydesignersto selectanapproachandlevelofrigorthatisappropriatefortheintendedendusersand applicationofthestudy. Inthisresearch,thegoalofthestudywastodeterminethelifecycleGWP,WDandEU fromacommercialaquaponicsysteminDenver,CO.Asecondgoalwastocomparethe resultsfromthisstudytootherliteratureLCAvaluesfromhydroponics,aquacultureand conventionalagriculturetoevaluateifanyofthesesystemsofferenvironmentalefficiencies foragriculturalproduction.Thesegoalswereachievedbyformingafunctionalunit, constructingsystemboundaries,andgatheringtherequireddata. Inordertoaccommodatefortheproductionoftwoproductsinthisagriculturalsystem, twoseparateLCAanalyseswerecompletedwithallocationsforresourceuse.Thefunctional unitforthelettuceproductionis1kgWMlettuce.Drymass(DM),althoughamoreaccurate measureasitexcludesfluctuationsinwaterconcentrations,wasnotusedforthisstudyas FlourishFarmmeasureseveryfulllettuceheadweightrightafterharvestandbefore deliveringtothecostumer.FlourishFarmsproduced60differenttypesofleafygreensduring the2014year(AppendixB),whichforthisstudywillallbereferredtoaslettuce.Each


33 speciesoflettucewasweighedatharvestandrecordedandtheaveragesellweightwas calculated.ThesecondLCAanalysisfocusesonthefishproductionoftheaquaponicfarm, withafunctionalunitof1kgoffish.FlourishFarmproducedtwodifferentspeciesoffish during2014,tilapiaandHSBwhichbothtogetherwillbereferredtoasfish.Forthis analysis,afishmassestimationhadtobeused,asthefarmcurrentlysellstheirfishwhole andonlyoccasionallyweighsthem.Fishmasswasestimatedfrompersonalcommunication withownerTawnyaSawyer,aswellasnotesinthesalessectionofthedatareportindicating approximatefishsizeandoccasionalweights.Theweightswerecategorizedintosmall (~28gm),medium(~170gm)orlarge(~396gm)foreachfishsold. ThesystemboundaryisasingleissueLCAapproach,withanOrderIanalysisfocusing ontheproductioncycleandtransportationofthefarminordertoascertaintheglobal warmingpotential,energyandwaterusewithinthefarmfortheentire2014year.Thescope includestheenergycarriers,naturalgasconsumption,wateruse,integratedpest management,deliverytransportation,andtheinputoffishfeedintothesystem(Goedkoopet al.,2013;Fig.12).


34 Figure12. SystemBoundaryColoradoAquaponicsFlourishFarmsLCA.Theabovefigure demonstratesaflowdiagramoftheboundariesoftheLCAforthisstudy.Thisstudyincluded thefishfeedproduction,wateracquisition,wateruse,pumpuse,lightinguse,integratedpest management,heatingandcoolingmechanismsandthetransporttothecustomers.Excluded fromthestudywerethenutrientadditionsandthebackgroundanalysisofthecapitalunits usedinproductionandtransportation. Inordertoclarifythesystemboundaries,thecomponentsweredividedintopre-farm, on-farmandpost-farm,whichwillhelpelucidatetheareasoutsideofthesystemboundary (Table2).


35 Table2. Pre-farm,on-farmandpost-farminclusionsandexclusionsinthisstudy. Pre-Farm On-Farm Post-Farm Inside Study Boundary Fishfeedproduction Pestmanagement production Heating Cooling Lighting Pumps Water additions Transportto customer Outside Study Boundary Infrastructure production Capitalproduction Nutrientproduction Materialstransportto farm Nutrient additions Packaging Storage Consumption stage Waste generation Avoided products TheWDandGWPwerebothcalculatedusing GaBiProductSustainabilitySoftware version5.0 GaBiV5.0 whichgeneratestheLCAofaproductaccordingtotheISO 14040/14044regulations,andusesthePAS2050andGHGProtocolProductandScope3 Standardtospecificallygeneratethecarbonfootprint.Forthisstudy,the GaBiV5.0 InternationalReferenceLifeCycleDataSystem(ILCD)wasused,usingtheU.S.LifeCycle InventoryandEcoInventdatabases. Outsideofthescopeofthestudywerethecapitalresourcesofthefarm,whichincluded thecradleproductioncostsofgreenhousestructure,tanks,piping,motors,heaters,fans, lightsandadditionalbuildingmaterials.Additionally,thefunctionalityofthisstudyfor ColoradoAquaponicsdidnotneedtheextensiverigortoincludethecapital,butrather focusingontheproductionhotspotsaccomplishedthegoal.Infuturestudiesofthefarm,


36 theseelementscouldbeinventoriedandincluded.Also,manyofthenutrientadditionstothe farmin2014werenotcategorizedforwhichchemicalswereincluded.Forinstance,a homebrewnutrientmixturecompromised90%ofthetotalnutrientadditionsfor2014,but thismixturewasconstantlychangedandnonoteswereprovidedastowhatwasincludedin eachsupplement.Becauseoftheseinconsistencies,thenutrientadditionswereexcluded. However,themainnutrientsupplytothesystemisthefisheffluent,whichhaszero environmentalimpact,andallowscomparisonofthisstudytoothersthatdoincludenutrient additions.Otherlimitationswerethespecificintegratedpestmanagementchemicalsthat wereusedwerenotavailableineitherdatabase.However,ageneralpesticideapplicationwas foundwhichwasusedforthisstudy.ThewateruseinthisstudywaspulledfromtheDenver Watermeterbills,andincludedalloftheuseonthefarmnotjusttheusageforproduction. Infuturestudies,calculationscouldbemadetodeterminethewaterusejustforproduction andexcludeallotheroperations. 2.2.2LifeCycleInventory Thelifecycleinventoryconsidersallofthenecessaryinputsandoutputsthatoccur duringthelifecycleoftheproduct.TheprocessdatawerecollecteddirectlyfromFlourish Farmsownersandwithinthedetailedrecordsofproduceandfishspeciesoutput,fishfood inputintothesystem,pestmanagementuse,electricaluse,waterbills,naturalgas consumption,andnecessaryequipmentforoperationalactivity.Thelifecycleinventory showsalloftheinputsintothesysteminordertoproduce1kgoflettuceand1kgoffish (Table3).


37 Table3. LifeCycleInventoryofFlourishFarms. Inputs Value Units LCIof1kgfish Fishfeed 0.69 Kg Pesticideproduction 0.0332 Kg Marketfortapwater 272 Kg Marketforelectricity 0.00843 mWh Marketfornaturalgas 4.83 kg LCIof1kglettuce Fishfeed 0.054 Kg Pesticideproduction 0.00259 Kg Marketfortapwater 130 Kg Marketforelectricity 0.00365 mWh Marketfornaturalgas 4.83 Kg Transporttocostumer 4,970 kgkm Thesevaluescorrespondtotheprocessflowscreatedwithinthe GaBiV5.0 software(Fig. 13&14). Figure13 .LifeCycleAssessmentProcessFlowforFish.Thisimage,takenfrom GaBiV5.0 software,exhibitstheinputsintothedatabasefortheproductionof1kgoffishfromthe farm.


38 Figure14 .LifeCycleAssessmentProcessFlowforLettuce.Thisimage,takenfrom GaBi V5.0 software,exhibitstheinputsintothedatabasefortheproductionof1kgoflettucefrom thefarm. Thesevalueswerecalculatedfrommonthlyutilitymeterreadingsofthenaturalgasand wateruse.Additionally,electricalconsumptionwascalculatedfromthekWhoperational datalistedoneachpieceofequipmentfortheforegroundanalysis.Theoperational equipmentbackgrounddatawasexcludedfromthisstudy.Thebuildingusesequipmentto controltemperature,humidity,lighting,andwaterflow.Theseincludefivehorizontalairflow fans,twoventfans,awetwallpump,circulationpump,fourHIDmetalhalidelights, intermediatebulkcontainerpowerpumps,amainMDMInc.ValuFlo6100waterpump (ColoradoSprings,CO),twomediabedwaterpumps,anNFTpump,threenurserypumps, onetowerpump,andanS31regenerativeairblower.Thesystemalsousesfishtankboilers, knownasfishsweatersandtwoModineheaters(Racine,WI)toheatthewaterand greenhouserespectively.Eachpieceofelectricalequipmentwasevaluatedfortheaverage hoursperdayitwouldrun,andseasonalvariationwascalculatedaswell(Table4).


39 Table4. ElectricalOperationalEquipmentatFlourishFarms.Thefollowingequipmentwas allresearchedforkilowatthourcapacity,seasonaluse,dailyuse,andnumberofunits.This combinedinformationwasusedtocalculatethetotalkilowattrequirementsforthefarm,and wasthenconvertedintomegaJoulesfortheEUfactorforthisstudy. Component Units kWhWattsOperational Hours Operational Days HAFFans 5 0.575 115 23 120 ModineHeaters 2 0.250 125 4 365 VentFanA 1 0.560 560 4 365 VentFanB 1 0.560 560 2 365 WetWallPump 1 0.060 60 0 120 CirculationPump 1 0.006 16 0 120 HIDMetalHalideLights 4 1.600 400 6 120 IBCtowerpump 1 0.145 145 0 365 ValuFlo6100WaterPump 1 0.207 207 24 365 MediaBedWaterPump 1 0.058 58 24 365 MediaBedWaterPump 1 0.033 33 24 365 NFTPump,Model18B 1 0.145 145 0.5 365 NurseryPump1 1 0.138 138 0.5 365 NurseryPump2 1 0.104 104 0.5 365 NurserySumpPump,Model18B 1 0.180 180 0.5 365 S31Blower 1 0.471 471 24 365 TowerPump 1 0.070 70 24 365 ThesevaluesweresummedtoproducethetotalkWhthefarmusesinoneyear.This valuewasconvertedintomegaJoulesforthisstudy,andreportedastheEU.Additionally, havingthisinventoryanalysisoftheoperationalequipmentallowstheendusertohighlight whichmachinerycontributesthemosttotheenvironmentalimpact. InordertocalculatetheGWP,thecubicfeetofcompressednaturalgasusedinthe ModineheatersandaquaponichotwaterheaterswhereconvertedintokilogramsofCO 2 productionusingequationsintheChemistryoftheElements(Greenwood&Earnshaw, 1997).TheCO 2 emissions(calculatedfromkg/km)forthetransportationtoFlourishFarms


40 customerbasewerealsoaddedintothe GaBiV5.0 software.Thesevalueswerethendivided bythetotalkilogramsoflettuceandfishtoproducethekgCO 2 e/kgvalue.ThekgCO 2 e/kg emissionsfromtheelectricalcomponentsofthesystem,lights,fans,heaters,andpumps, wereincludedintothetotalGWPcalculationaswell. TheWDdatawerecollectedusingmeterpullsfromDenverWaterforthefarmwithinthe GrowHausthrough2014.Thesedataincludeallwaterusedbythefarm,notjustwhatwould beinsertedintothesystemtoreplacedailyevaporationandtranspiration.However,the majorityofwateruseatthefarmisusedforreplenishingwaterlostfromtranspiration,plant massgrowthandevaporation. FlourishFarmobtainsitsPondLow-EnergyfishfeedfromSkrettingUSA,aNutreco company.LCAdatawereobtainedfromtheSkrettingAustraliaAnnualSustainabilityReport (2014),acradletogateLCAanalysis,whichwasincorporatedintothestudytoaccountfor GWP,EUandWDforthefarmsfishfeedinput.Eutrophicationdatawerenotincludedin thesustainabilityreport.Todate,,sothe datafromtheAustraliafacilitywereusedasaclosecomparison.Theproductscomponents arelistedinFigure15. Figure15. SkrettingsPondLEfishfeedcomponents.Flourishfarmsusesthe5.5mm floatingsize(


41 Thetransportationgreenhousegasemissionswerecalculatedusingalistofthedelivery locationsandfrequencyreportingfromthefarm.FlourishFarmsdeliverstheirownproduce andallfisharesoldattheGrowHausfacility.Inordertocalculatetheaveragedelivery weight,ninedeliverieswerecategorizedintoproducttypeandweighed,andthenthat averagewasusedforothercalculations.TheoptimalroutewascomputedusingGoogles OptiRoutebyinsertingthe21deliverylocations(Fig.16;AppendixA).Thisroutewasnot usedbyFlourishFarmseveryweek,aserrandsanddeliveriesvaried,butisanaverage approximationfortheyear.ThemileageforeachtripfromOptiRoutewasmultipliedacross thenumberofdeliveriesperyeartoobtainthetotalmileagefor2014.


42 Figure16. FlourishFarmsdeliveryroute.FlourishFarmsdeliversto20businessesinthe surroundingDenverarea.Eachtripis24.3milesroundtrip,andthedeliveriesaretakentwice aweek.SeeAppendixAfordeliverylocations. Althoughtheaquaponicfarmusedeightvariousintegratedpestmanagementtechniques (AppendixC),noneofthesewereavailableinthe GaBiV5.0 database.Conversely,ageneric pesticideproductiondatabasewasavailable,whichwasusedforthisstudy.Flourish Farmspestmanagementfocusesonlowenvironmentalimpactproducts,andthe GaBiV5.0 databaseoptiondoesnotincludethis.Asaresult,theenvironmentalimpactfromthepest managementmayreflectslightlyhigheroutcomesthantheactualpesticidesusedwould represent.However,thepestmanagementisaminorinputcategory,sotheeffectsfromthis discrepancyarenotconsideredtobesignificant.


43 Theaquaponicfarmcontainsmanycapitalcomponentsinordertorunatacommercial scale.AlthoughthebackgrounddatafromthesecomponentswerenotincludedinthisLCA, theinfrastructureislistedinTable5inordertogainanunderstandingofthescaleandspace requiredforthisfacilitytooperate. Table5. NecessaryinfrastructureinFlourishFarmsaquaponicsystem.Thefollowing materialsaretheentiremaininfrastructureinColoradoAquaponicsfarm. Component Volume(m 3 ) Dimensions(m) RaftBed1(MediaandDWC) 7.86 1.22Wx23.16L RaftBed2DWC 7.86 1.22Wx23.16L RaftBed3DWC 5.76 1.22Wx7.92L RaftBed4DWC 11.52 2.44Wx23.16L NFTPumps 30.48L WoodFishTank 2.03 0.92Wx3.35Lx0.61Deep MainFishTank 3.18 2.29Diameterx1.02Deep BlueTank(ConeBottom) 1.76 1.57Wx1.57Lx0.71Deep BrushFiltrationTank 0.68 0.66Hx1.35Lx0.94W ClarifierFilter(ConeBottom) 0.45 0.71Diameterx1.47H Themaininfrastructuresarefourraftbeds(threeDWC,andonewithbothDWCand media),30mofNFT,a2m 3 woodenfishtankforyoungerfish,a3m 3 maintankformature fish,anda1.76m 3 conebottomtank.Therearealsotwofiltrationsystemstoremovesolids fromtheeffluentinordertopreventwasteaccumulationandrootdamage.Theentiresystem ishousedinarepurposedgreenhousethatwasconstructedinthe1970s.Thegreenhousewas renovatedtobeagrowingenvironmentin2012(JDSawyerpersonalcommunication,2016). 2.2.3LifeCycleImpactAssessment TheimpactassessmentcalculatestheGWP,WDandEUusebasedoffofthevaluesfrom theinventoryanalysis.Alifecycleimpactassessmentthentransferstheemissionsand resourcedataintoindicatorsthatreflectenvironmentandhealthpressuresaswellasresource


44 scarcity(ILCD,2011).Thisrequiredafourstepprocess(1)allocatingtheresourcestothe twoco-productswithinthesystem,(2)calculatingthetotalgasuse,wateruseandelectricity useproducedbyeachprocess,and(3)convertingthegasuseintoCO 2 equivalency(CO 2 e) fortheGWPcalculation,convertingtheelectricityuseintomJ,andconvertingthewateruse intom 3 ,asallofthesearethestandardunitforcomparisoninLCAstudies. Allocation. Allocationisapartitioningpracticeusedtodividetheinputoroutputflows ofaprocessbetweentwoormoreproductsystems(ISO,14044).Sincethefarmhasthecoproductsoffishandvariousproducefromthesameresources,theinputdatawereallocated totwocategoriesofproductionusingeconomicprofits,aspracticedbyotheraquaculture LCAstudies(Ayeretal.,2008).Thisresultedin16.3%oftheresourcescontributingtothe aquacultureproduction,and83.7%oftheresourcestothelettuceproduction.Fromthese allocations,twoseparateLCAswerecompleted.Oneusing16.3%ofallresourceuse allocatedtoaquacultureproduction,andthesecondusing83.7%ofresourceuseallocatedto lettuceproduction.ThisallocationalsoallowedtheLCAresultsofthefishproductionin aquaponicstobeapproximatecomparedtoliteraturevaluesofLCAsforaquaculture,andthe LCAresultsofthelettuceproductionintheaquaponicsystemtobecomparedtotraditional agricultureandhydroponiclettuceproduction. TotalResourceUse. Theinventoryanalysiswasinsertedinto GaBiV5.0 inorderto calculatetheGWP,WDandEUfortheaquaponicsystemfor1kgoflettuceand1kgoffish production.TheinputandoutputdatawerelinkedtoEcoInventandU.S.LifeCycle Inventorydatabasesin GaBiV5.0. Thesedatabasescontaindataonmaterials,emissionsand energyconsumptionforthemanufactureofoneunitofproduction. Conversion. Oncetheinputsarelinkedtothecorrectdatabases, GaBiV5.0 software convertstheinputunitintotheoutputunit,basedonthebackgrounddatabaseinformation.


45 FortheGWPconversion,alloftheemissionscalculationsarecompletedfortheelectricity use,naturalgasuse,transportation,andwateracquisition.TheGWPalsoincludedthe emissionsusedtoengineerthefishfeedandintegratedpestmanagement.Thesoftware automaticallycompletesanynecessaryconversionrequiredtoaccountforgreenhousegases thathavevaryingglobalwarmingpotenciesintoastandardof1kgofCO 2 .Forinstance, accordingtotheIPCCCH 4 hasaglobalwarmingpotentialthatis21timeshigherthanCO 2 over100years(IPCC,1996).Thewaterdependencywasconvertedfromkgofwaterintom 3 andincorporatedthewaterusedonthefarm,aswellasthewaterdependencyusedforfish feedandthepesticide.TheEUforthisstudywashandcalculated,usingtheconversion factorof1kWhto3.6megaJoule(mJ),asthe GaBiV5.0 softwaredidnotreportthismetric. TheInternationalReferenceLifeCycleDataSystem(ILCD)analysiswasusedastheimpact assessmentmethodforthisstudy.TheILCDpublishedtheRecommendationsforLifeCycle ImpactassessmentintheEuropeanContextwhichchoosesthemethodologyforeachimpact categorythathasbeenevaluatedasthebest(ILCD,2011).AlthoughtheToolforthe ReductionandAssessmentofChemicalandotherenvironmentalImpacts(TRACI2.1), developedbyU.S.EnvironmentalProtectionAgency(EPA),canhavemorecontextual significanceforastudydoneintheU.S.,TRACIdidnotincludeanymetricsonwater dependency,whereastheILCDLCIAdoesincludethisasanimpactcategory,whichwas importantforthisstudy.TheprocessflowsforthelettuceandfishLCIAareshownin Figures13and14. 2.3 Results FlourishFarmsusedatotalof14,157kgofCO 2 equivalencyinordertoproduce2,700kg oflettuceand252kgoffishin2014.Thetotal2014EUforthesystemwas33,670mJ,and theWDwas420m 3 foralloperations.FlourishFarmshadzeromaterialwaste,asallsolids


46 removedfromtheclarifierfilterweremixedintoafertilizersolutionforuseinsoilbased gardens,lawns,compostandfoliarsprayswithintheGrowHaus.Allrootsfromthe vegetableswereeithersoldwiththeproduct,ortrimmedandusedincompostingbins. The farmusedatotalof0.74kgoffishfeedperkgofcombinedfishandlettuceproductionand thefarmused0.04kgofintegratedpestmanagementperkgofproduction.FlourishFarm delivered307kgofproducetotheircustomers,with4084kilometersdriventhroughoutthe year,fromatwiceweeklydeliveryschedule.Thisaccountsforthe13.3kilometersper kilogramoflettucedelivered.Thefarmcurrentlysellsordonatestheremaining89%oftheir produceand100%oftheirfishwithintheGrowHaus. ThisaquaponicsystemhadaGWPof12.95kgCO 2 e/kg,whichcombinestheLCA analysisofthefishandlettuce(Fig.17&18,respectively).TheEUforthefarmtotaled 32.38mJ/kg,andtheWDwas0.1945m 3 /kg(Table6).TheGWPis63%fromtheelectric requirements,26%fromthenaturalgasuse,6%fromtransporttocustomers,andthe remaining5%wasattributedtothepestmanagement,tapwateracquisitionandfishfeed (Fig.19).


47 Figure17. GlobalwarmingpotentialoffishproductionatFlourishFarm. 8.5 0.00345 2.26 5.675 0.187 0.376 0 1 2 3 4 5 6 7 8 9 Total FishFeed NaturalGas Electric TapWaterIntegratedPest Management G W P ( k g C O 2 e / k g o f f i s h ) InputstotheFarm


48 Figure18. GlobalwarmingpotentialoflettuceproductionatFlourishFarms. Table6. Thetotalglobalwarmingpotential(kgCO 2 e),energyuse(mJ)andwater dependency(m 3 )forFlourishFarmlettuceandfishperkilogramin2014. Mass Produced (kg) Units Produced Economic Allocation (%) GWP (kgCO 2 e/kg) EU (mJ/kg) WD (m 3 /kg) Fish 252 1,685 16.3 8.50 21.77 0.1350 Lettuce 2,700 30,553 83.7 4.45 10.44 0.0595 Total 2,952 32,238 100 12.95 32.38 0.1945 4.45 0.000162 1.08 2.454 0.0895 0.0294 0.786 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Total FishFeedNaturalGasElectric TapwaterIntegrated Pest Management Transport G W P ( k g C O 2 e / k g o f l e t t u c e ) InputstotheFarm


49 Figure19. DistributionofglobalwarmingpotentialkgofCO 2 e/kgofproductionwithin FlourishFarms. Theresultsfromthisstudywerethencomparedwithresultsfromtheliteratureinorderto evaluatetheenvironmentalcostsofaquaponicscontrastedtohydroponicsystems, aquaculturesystemsandtraditionalagriculture. Inordertocomparethelettuceproductionfromaquaponicstohydroponicsand traditionalagriculture,theresourceallocationof83.7%wasused.Theallocationpercentage wasappliedtoeachresourceinputintothefarmforthelettuceLCA.Thelettuceproduction intheaquaponicsystemhadahigheryieldthanirrigatedtraditionalagricultureby18.12 kg/m 2 andaloweryieldthanhydroponicsby18.98kg/m 2 .TheGWPofaquaponicswas 4.45kgofCO 2 e/kg,higherthanbothhydroponicsandirrigatedtraditionalagriculture,which FishFeed ~0% NaturalGas 26% Electric 63% TapWater 2% Pest Management 3% Transport 6%


50 were0.90 and0.86kgofCO 2 e/kgrespectively.Thedataindicatedthataquaponicshada lowerWDthanirrigatedtraditionalagricultureby0.19m 3 /kg,butahigherWDthan hydroponicsby0.04m 3 /kg.EUwasthehighestinhydroponicsystems,withaquaponics lowerby79.42mJ/kg.AquaponicshadahigherEUthantraditionalagricultureby9.48 mJ/kg.Therainfedagriculturehada21.89kg/m 2 loweryieldthanaquaponics.However, rainfedagriculturealsohadthelowestGWPwhencomparedtoallotherfarmingsystems. TheWDofrainredagriculturewas0.02lowerthanaquaponics,and0.02higherthan hydroponics.EUcalculationswerenotavailableintheHalletal2014study(Table7). Table7. Comparativeofannuallanduse,waterdependencyandenergyuseinaquaponics, hydroponicsandtraditionalagriculturefor1kilogramoflettuceproduction.Theaquaponic dataforthiscomparisonusedthe83.7%allocationofresourcesusetorepresentonlythe lettuceproductioncomponentofthesystem. ThefishproductionofaquaponicswasthencomparedtovariousaquacultureLCA studies,usingthe16.3%allocationofresources.Theallocationpercentagewasappliedto eachresourceinputintothestudyforthefishLCA.Thisstudyindicatedthataquaponicshad aslightlyhigherGWPcomparedtootheraquaculturesystems,exceptforthearcticchar AgriculturalType Yield (kg/m 2 ) GWP (kgofCO 2 e/kg) WD (m 3 /kg) EU (mJ/kg) Reference Aquaponics 22.02 4.45 0.06 10.58 Currentstudy Hydroponics 41.006.10 0.90 0.020.01 90.0011.00 Barbosaetal2015 Rothwelletal2016 Traditional AgricultureIrrigated3.900.21 0.86 0.250.03 1.100.08 Barbosaetal2015 Plaweckietal2015 Traditional AgricultureRainfed0.130.08


51 recirculationsystem(Ayer&Tyedmers,2009).WhiletheBainbridge(2012)andBoxman (2016)aquaponicstudyshowedamid-rangeEU,thisstudysaquaponicsystemhadthe lowestEUofallsystems.AllaquaponicsystemshadthelowestWDcomparedtoallother aquaculturetypes(Table8). Table8. ComparisonofGlobalWarmingPotential,EnergyUse,andWaterDependencyof variousaquaculturesystemswithvaluesintermsofonekilogramoffishproduction.The aquaponicdataforthiscomparisonusedthe16.3%allocationofresourceusetorepresent onlytheaquacultureproductioncomponentofthesystem. FishType SystemType GWP (kgCO 2 e/kg) EU (mJ/kg) WD (m 3 /kg) Reference Tilapia&HSBTemperateAquaponics8.50 21.79 0.135 CurrentStudy Tilapia TemperateAquaponics7.18 121.25 0.01 Bainbridge2012 Tilapia TropicalAquaponics 9.52 123.46 -1.50 Boxmanetal2016 Turbot Recirculation 6.02 290.99 4.81 Aubinetal2006 Rainbowtrout Flowthrough 2.02 34.87 98.80 Roqued'Orbcasteletal2009 Rainbowtrout Flowthrough 2.75 78.23 52.60 Aubinetal2009 Rainbowtrout Recirculation 2.04 63.20 6.63 Roqued'Orbcasteletal2009 Seabass Netpen 3.60 54.66 48,720.00Aubinetal2009 ArcticChar Recirculation 28.20 353.00 AyerandTyedmers,2009 AtlanticSalmonNetPen 2.07 26.90 Ayerand Tyedmers,2009 2.4 Discussion 2.4.1ImpactAssessment Thefieldofaquaponicfarminghasbeenrapidlygrowingoverthepastdecades,butthere havebeenveryfewrigorous,peer-reviewedsystemsresearchpublishedonthetopic. Becauseofthis,assessmentofthesesystemsisneededinordertoprovidestakeholders informationonthebenefitsandcostsofaquaponicsandthepotentialthesesystemshavefor,(2014)LCAhas


52 beenshowntobecapableofproducingsomenontrivialresultsthatcanbesignificantly helpfulwhenitcomestodecisionmaking.ThisLCAdemonstratedthataquaponicshas beneficialreductionsforsomeenvironmentalimpactsassociatedwithfoodproduction,butit hasahigherimpactinothercategories.Aquaponicsshowedagreatpotentialforincreasing yieldperlandarea,whiledecreasingwaterusecomparedtoconventionalagriculture.The lettuceproductioninaquaponicswasalsooutperformedbyhydroponicsinregardstoyields andwateruse.However,thisaquaponicsystemusedlessenergythanthecomparative hydroponicstudiesfromtheBarbosaetal.,study(2015).Thisstudyuseddatafocusingon agriculturalpracticesinArizona,USas29%oflettuceproductionnationwideoccursinthis state(Barbosaetal.,2015).Theconventionalagriculturerangesweredeterminedfroman orderofmagnitudestudyfromAckeretal.(2008)thatfocusedontherequiredenergyand waterforalllettucecultivationinArizona(aswellasothercrops).Thehydroponicdata fromtheBarbosaetal.(2015)studywasfromanenterprisemodelfromtheOhioState University,usedtoestimatetherevenue,expenses,andprofitabilityassociatedwith greenhouselettuceproduction.Datawasalsotakenfromtwomorehydroponicstudiesto estimatewaterandenergyuse.Thesecomparativestudiesforhydroponicsandtraditional agricultureinArizonahaveawarmerclimatethanDenver,Colorado.Inordertocompare howsustainableaquaponicsisasalocalfoodproductionsystemforthiscity,itwouldbe helpfultocomparetoagriculturalsystemswithinthisstate,whichsofar,havenotbeen completed.Rainfedagriculture,incomparison,hadmuchloweryieldsthananyother productiontype.However,theyhadacorrespondinglowGWPvalueaswell.Although primarilyrainfed,thefarmersintheHalletal.,studydidsupplementwithirrigationwhen needed,whichresultedintheslightlyhigherWDthanhydroponics.Therainfedagriculture WDwasstilllowerthanirrigatedtraditionalagricultureandaquaponics.Inregardstofish


53 production,aquaponicscontributedmoretoGWPthanallothertypesofaquacultureexcept foranarcticcharrecirculationsystem(Ayer&Tyedmers,2009).However,theEUandWD forthisaquaponicstudywasthelowestofallaquaculturesystems,whichhasthepotential fornaturalresourceconservation.Thecomparisonbetweentemperateandtropical aquaponicsshowsthatregardlessoftheclimate,theGWPisstillhighfortheproduction. ThisispotentiallyfromtheUniversityofVirginIslandssystemfocusingprimarilyonfish production,whileFlourishFarmsprimaryproductislettuce.TheBoxmanetal.,(2016)study alsousedthebasilproductionasacredittotheirsystem,insteadofusinganadditional functionalunit.Thisresultedinseveralavoidedproducts,whichiswhythereisanegative WDforthissystem.However,thewateradditionsfortheBoxmansystemwere0.16m 3 /kg, whichwas0.03m 3 /kghigherthanFlourishFarms.Thesecomparisonssuggestthatalthough itwouldbelogicaltoassumegainedproductionefficienciesfromatropicalclimatesystem thatdoesnotneedagreenhouse,thisisnotnecessarilythecase. Thisstudyidentifiedareaswhereefficienciescouldbebuiltintoaquaponicsinorderto haveamoresustainablesystem.TheGWPforaquaponicswashigherthanotheragricultural systems,andcouldbereducedbythefarmconsideringalternativeenergysolutions,suchas purchasingwindenergyfromtheirsource.Thefarmcurrentlyhasplanstoinstallsolarpanels whichwillreduceboththeGWPandtheEUforthesystem.Presently63%ofFlourish FarmsGWPisfromtheelectricalusageofthefarm,and26%fromthenaturalgas consumption,sothisimprovementcouldhelpreducetheseelectricalusagecomponentsfrom thefarm.Oneofthehot-spotsforelectricalconsumptionwastheuseofthehalidelightsfor sixhoursadayduringthewinter.Inthefuture,convertingtoLEDlightscouldreduceenergy useforthiscomponentby60%,althoughthegreatercapitalcostforthelightswouldneedto beconsidered.Partofthishighnaturalgasconsumptioncomesfromthetemperate


54 continentalclimate,whichgenerateshotsummersandverycoldwinters,requiringhigh temperaturemediation.Theaquaponicwatercultureiskeptconsistentlybetween21Cand 22.7C,andthegreenhouseairtemperaturesrangefrom12.7to23.8C.Thisamountof temperaturecontrolinadrasticallychangingclimateinColoradoisenergyintensiveto maintain.AnotheraspecttoconsideristhebuildingwhereFlourishFarmsislocatedisina repurposedhistoricgreenhousefromthe1970s,whichlacksmoderninfrastructuretomore efficientlyretainheat.Solarthermalheatingandwaterheatingcouldbeappliedtothe buildingtoreducetheGWP,aswellasaclimatebattery,whichcouldstorehotair undergroundtouseduringthecoldweather.Oneadvantageaquaponicshasincomparisonto traditionalagricultureisthelocalcustomerbase.Flourishfarmssellsanddeliversallofits productswithinan8kilometerradius.OneofthepotentialreasonsthattheGWPfor aquaponicsexceededthatoftraditionalagricultureistherelianceonelectricityandheatfor thesystemtooperate.Whileconventionalfarmsdoirrigateandhavemachineryfortilling, weedingandharvesting,rarelyareallofthesecomponentsoperatingtwenty-fourseven.In anaquaponicsystemthewaterpumps,circulators,aerators,andheatingorcooling mechanismneedtobeononehundredpercentofthetime.Ifoneoftheseelementswereto fail,therewouldlikelybealargefishdie-off,astherewasinthisfarmwhenthegenerators failed.However,thebenefitfromtheconstantcirculationistheincreasedyieldandyear roundproduction,whichmanyMidwesternagriculturalsystemscannotoffer. Duringthecourseofthisstudy,FlourishFarmsharvestedbothtilapiaandHSB.HSBwas thoughttobebeneficialbecauseitcanberaisedinlowerwatertemperaturesthantilapia,and thereforesavingonwaterheatingcosts.However,tilapiaandHSBbothgrowoptimallyfrom 23Cto27C.FlourishFarmstypicallykeptwatertemperatures1to2Clowerthan optimallygrowingrecords.Onerecommendationwastoreducethewatertemperaturefurther


55 whiletheHSBweretheprimaryspecies,sincetheyaremoreresilientundercoldconditions thantilapia.FlourishFarmsactuallydidattemptthisgrowingtechniquetoreduceGHGand heatingcosts.Theyloweredwatertemperaturesto10CandfoundthattheHSBwerestill sustained.However,becausethereducedtemperaturesslowedtheHSBgrowth,the nitrificationprocessslowedaswell,doublingtheamountoftimeforthelettuceproductionto reachharvestsize.Thereductioninprofitharvestablevegetableswasactuallyfargreater thanthecostssavedinheatingoverthewinter. WhiletheWDforaquaponicswaslowerthantraditionalagricultureandaquaculture,it wasstillhigherthantheprojected10%ofwaterusageoftraditionalagriculturethatmany studiessupport(Somervilleetal., 2014;Lennard&Leonard,2006;Bainbridge,2012).This LCAindicatedthataquaponicsuses24%lesswaterthantraditionalirrigatedagricultureand inadesertclimate.FlourishFarmsgoingforwardshouldcarefullytrackwherewaterisbeing appliedinthesystem,andlookforanypossiblereductions.Anotherpossiblereductionis Denverapprovedrainwatercollectionin2015,whichcouldbeanotherwatersourcethefarm couldutilizeinsteadoftapwater(Gauldin,2015).TheBainbridgeaquaponicLCApredicted thata0m 3 WDcouldbeachievedintheirsystembyrelyingonrainwatercollectionalone (2012).Thefarmalsoexperiencedseveraloperationalemergenciesduring2014,whichcould havecausedaneedforthesystemtobeflushedandheavywateruseduringthistime. Additionalyearsofdataandnotesoffuturenotesofhighwaterusagemayprovethat2014 wasanoutlierinWDforFlourishFarms. Thelettuceyieldforaquaponicsshowspromiseastheproductionwas560%higherthan traditionalirrigatedagricultureand16,838%higherthanrainfedagriculture.Higheryields canresultinmoreeffectivelanduseplanningandmanagement,whichwillbecome


56 importantaswecontinuallytrytofeedmorepeoplewithlessspace.Landthatissavedfrom intensiveagriculturecouldbeuseforconservation,whichcouldimprovetheenvironment. Somepointsofconsiderationforthisstudythatmaycontributetouncertaintyinthe results,isFlourishFarms,upuntilrecently,didnotweightheirfish.Themethodforsales includedestimatingfishlengthatapproximately12.7cmlongorplatesizeandsellingthe fishforanevenfiveUSD.Typicalaquaculturestudiesmeticulouslyweightheprotein producedandsellthefishbyweightwhichgivesveryaccurateproductionnumbers,instead oftheestimatesusedinthisstudy.Thefarmalsoexperiencedadramaticdie-offduringthe 2014yearinwhich491fishdiedduetolossofelectricity.Inordertoaccountforthisdieoff, thisstudyaddedthesefishweightsintotheproteinproduced,eventhoughthisproteinwas notsold. Additionally,manystudiesusetheDMvalueofplantmassasabetterindicationofthe actualproduction.DMdoesnotincludethewateraccumulatedwhilegrowing,andtherefore hasagreaterconsistencythanWM.Aswaterhasnonutritionalcomponents,itisnotidealto usethewaterweightwithintheproductaspartoftheproduction.However,sincethedatafor thisstudyweretakenfrom2014FlourishFarmshadalreadyweighedtheirproductsbefore theviewingofthedataandanyalterationscouldoccur.Onerecommendationforfuturedata collectionswouldbetohaveDMvaluesforeachproductthatthefarmisselling,inorderto havemoreaccuratemeasureofthefoodproduced.Anotherdatacollectionrecommendation wouldbetohaveconsistencyinthemetricsthatarebeingcollected.Notalldatapointsinall yearshadconsistentutilityreadingsorfishcounts.Otherhelpfulmetricswouldbedaily watertemperaturereadings,airtemperaturereadings,andmorepreciserecordingsof equipmentoperationthroughouttheyear.


57 OneissuewithcomparingLCAresultstootherLCAliteraturestudiesisthatrarelywill thestudyboundariesreflectthesameexactinclusionsandexclusions.EachLCAis completedwithindividualgoals,andthereforethestudiescanbedifficulttocompareequally assomestudieswillincludemoreoftheprocessthanothers.Thisisaconcernforthisstudy assomeoftheliteraturevalues,( e.g. Barbosaetal.,2014)usedfewerproduction componentsthanthisstudy,whileothers( e.g., cradletograveaquaculturestudies)usedmore productionandlifecycleeventsthanthisstudy.Unfortunately,withoutcompletingarange ofLCAstudiescompromisingofvariousstudyboundariesthisissuecannotbeavoided. LCAswillusuallyonlycompareifthetwosystemsanalyseswerecompletedbythesame researcher,sothevariableforthestudyboundarywillbeconsistent.Inordertoaccountfor thisdiscrepancy,thevaluesforthisstudyareprimarilyusedforthefarmsbenefit,andnotas concretecomparativevalue.Aconfidencevariationanalysiscouldhelptomakethe comparisonsmoreeffective. Additionally,theallocationmethodsforthisstudycouldbeimprovedsincetheeconomic productionrequiredsomeestimationinregardstofishweightsandsales.Amethodinvolving resourcerequirementsormassforeachsubcategoryofproductionmaygeneratebetter allocationpercentagesandwillbeconsideredforfutureresearch.Ultimately,bettersystems informationwillquantitativelyaddresshypothesesabouttherelativeefficienciesof aquaponicvs.otheralternativefarmingtechniques. Localyear-roundfoodproductionisbecomingincreasinglyimportanttocommunities lookingtohavehigherfoodsecurityandfoodsovereignty,andaquaponicsisamechanism thatcommunitiescanexplore.LCAscanhelpindividualsandcommunitiesevaluateifthis foodproductionsystemistherightfitforthegoalstheyhopetoachieve.


58 2.5Conclusions Thisstudyhasshownthataquaponicspossessescertainenvironmentalbenefitsas comparedtootheragriculturesystems.Ifappliedonalargerscale,aquaponicscouldhave significantpositiveenvironmentalimpactsonthefoodsystem.Thisproductionsystemalso showspromiseininternationaldevelopmenttoincreaseaccesstoaffordableproteinwhen therearelimitedoptionsavailable.Thisresearchdemonstratedthattheremaybewaysto producehighqualityproteinandproduce,thathaspotentialtobelessenvironmentally wastefulandcostlythantraditionalagriculture,hydroponicsandaquaculture.Further investigationandimplementationofalternativefoodsystemscouldbeastepinincreasing localfoodproduction,andshiftingawayfromtheindustrialglobalfoodmarket.


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66 APPENDIXA FlourishFarmsDeliveryLocations 1. TheGrowhaus4751YorkStreet,DenverCO80216 2. BlueMoonBrewingCompany3750ChestnutPlace,DenverCO80216 3. ComidaattheSource3350BrightonBoulevard#105,DenverCO80216 4. MondoMarket3350BrightonBoulevard#115,DenverCO80216 5. ThePopulist3163LarimerStreet,DenverCO80205 6. ThePreservery3040BlakeStreet#101,DenverCO80205 7. Nocturne133027 th Street,DenverCO80205 8. AloyThai2134LarimerSt.,DenverCO80205 9. VestaDippingGrill1822BlackStreet,DenverCO80202 10. CholonModernAsianBistro-1555BlakeStreet#101,DenverCO80202 11. SqueakyBean-1500WynkoopStreet#101,DevnerCO80202 12. CentralBistro1691CentralStreet,DenverCO80211 13. WesternDaughtersButcherShoppe3326TejonStreet,DenverCO80211 14. Linger2030West30 th Avenue,DenverCO80211 15. St.KiliansCheeseShop3211LowellBlvd,DenverCO80211 16. CharcoalRestaurant43West9 th Avenue,DenverCO80204 17. MarczyksFineFoods(17 th )770East17 th Avenue,DenverCO80203 18. ThumpCoffee1201East13 th Avenue,DenverCO80218 19. SAMECaf2023EastColfaxAvenue,DenverCO80218 20. DenverZoo300SteeleSt.,DenverCO80205 21. MarczyksFineFoods(Colfax)5100EastColfaxAvenue,DenverCO80220 22. ThePlimoth2335East28 th Avenue,DenverCO80205 23. GrowHaus-4751YorkStreet,DenverCO80216


67 APPENDIXB FlourishFarmsProduceProduction2014 Values RowLabels Sumof Units harvested Sumof Harvested weight(oz) Averageof Average weight/unit(oz) BabyGreensmix 166 367 2.58 BasilGenovese 48 104 2.17 Bokchoytatsoi 1148 2433.12 2.631034483 BrightLights RainbowSwiss Chard 93 365.25 1.67 CeleryUtah 55 80 1.45 Chinesecabbage Michihili 52 189 3.77 CilantroCalypso 327 633.2 2.145833333 CollardGreens 23 84 3.65 CollardsVates 250 447.25 2.02125 Commonmint 103 260 3.14 Dwarfbluecurled kale 142 370.25 3.266 EndiveSaladKing 51 122.45 2.4 Flat-leafparsley 22 143 GrandRapidslettuce GreenStar 2549 9393.69 3.373069307 GreenBibbLettuce 3 12 4 Greenbibblettuce Buttercrunch 522 1057.75 2.484615385 GreenBibbLettuce Flandria 679 2549.19 3.789 Greenbibblettuce Rex 5129 16612.90167 3.439322034 Greenbutterhead lettuce 133 561 3.428 Greenromaine Claremont 364 1395.9 3.574285714 GreenromaineGreen Forest 26 179 6.88 Greenromaine Ridgeline 16 86 5.38 Helviusromaine 24 126 5.25 Hybridkale 105 298.75 2.9425 KaleStarbor 1514 3455.5 2.812826087 Machecornsalad 27 92 3.41 MustardGreens 194.5 336 2.97


68 NewRedFire ParrisIslandromaine 8089 27568.71 3.433843416 Purplemizuna 473 1490.8 3.541764706 PurslaneRedGruner 42 86.6 2.19 RedBibbLettuce Cherokee 40 209.5 RedbibblettuceRed Cross 46 171 3.925 Redbibblettuce Skyphos 76 312 4.156666667 Redbutterhead lettuce 16 64 4 RedGiantmustard 252 1121.875 4.0375 RedleaflettuceLollo Rossa RedLettuce Cherokee 23 132.75 Redoakleaflettuce Malawi 97 309 3.245 Redoakleaflettuce Oscarde 669 1567.885 2.212 RedromaineGarnet Rose 28 96 3.43 Redromaine Outredgeous 73 251 3.5825 RedromaineRouge d'Hiver 26 105.5 4.06 RedRussiankale 2564 6838.665 2.891392405 RedSummerCrisp lettuceCherokee 849 2519.24 2.985151515 Redvelvetlettuce 42 144 3.145 Redborkale 7 14.5 2.07 Red-veinedsorrel 203 402.5 2.504285714 RidgelineRomaine 48 207.75 4.63 RomaineCoastalStar 80 352 4.383333333 Romainelettuce Freckles 24 94 3.92 RomaineRedRosie 20 24 1.2 RomaineRidgeline 130 758.1 3.345 RomaineSparx 175 769.24 2.39 SwisschardBright Lightsrainbow 1756 5139.6 3.355769231 Orange Swisschardwhite 56 286 5.105 Tuscankale 828 2289.25 3.033214286 Watercress 56 144 2.57 GrandTotal 30553.5 95223.66667 3.240651751


69 APPENDIXC FlourishFarmsIntegratedPestManagementUse2014 RowLabels SumofPreparation (mL/L) Aqua-C 4750 Azamax 32 Azatrol 214 biominCa 6 Botanigaurd 91.5 Bti 2392 M-pede 294 Serenade 756 GrandTotal 8535.5