Abstract
The concept of aquaponics gained a lot of attention in the last couple of years. This concept of urban farming is a combination of aquaculture, rising fish, and hydroponics, the soil-less growing of plants. This technique can be used to provide a more sustainable food system in countries with rapid urbanization. This manuscript contains a brief explanation on the systems and looks into the advantages and disadvantages of the system. This is done by looking at the three pillars of sustainability, environment, economic and social. Some impacts and challenges were found and described within these three pillars. Eventually this manuscript tries to investigate if there exist an opportunity to implement aquaponics on a commercial scale. Therefore a review on earlier research is conducted.
Introduction
The world is changing and the problem of rapid urbanization is rising. At the moment more than 70% of people in Europe are living in an urban area. Expected is that this number will raise to 80% by 2050 (Connolly, Campion, & Rudden, 2018). The reason that more and more people are moving to the urban areas is because of the high work and job opportunities. However, urban living brings a range of environmental challenges. Therefore we need new models of urbanization, namely sustainable urbanization. Sustainable urbanization is the challenge that urbanization is in line with the principles of sustainable development (D’Auria, Tregua, & Vallejo-Martos, 2018). The principles of sustainable development involves three pillars. Sustainable urbanization therefore tries to contribute to these three sustainable pillars focused on social, environmental and economic issues (D’Auria et al., 2018).
At the moment most of the cities are not sustainable (Lang, 2018) and the world is still facing serious problems such as population rise, climate change, soil degradation, water scarcity and food security (dos Santos, 2016). Cities are trying to work towards such approaches to provide local renewable energy sources, local food production, extension of urban sprawl and sustainable transportation. This manuscript focus on the concept of local food production within urban areas. This is done by highlighting a technique called “aquaponics”.
Aquaponics is an approach of combining aquaculture, rising fish, and hydroponics, the soil-less growing of plants (König, Janker, Reinhardt, Villarroel, & Junge, 2018). This technique can be used to provide a more sustainable food system in countries with rapid urbanization. This technique can also be used in areas with a low local food production of fish and vegetables (Kyaw & Ng, 2017). This way of producing fish and vegetables is a natural environmentally friendly and sustainable way of food production, without the water being changed or chemical fertilizers to be applied. The remainder of this manuscript contains a brief explanation how the system works, the advantages and disadvantages of the system and an investigation of the economic future of aquaponics.
Concept
The idea behind aquaponics, combining fish and soilless plant production systems (Palm et al., 2018), exist already for more than 40 years. The first ideas about the technique were already mentioned in the book “Fish farming and hydroponics” in 1975 (Sneed, Allen, & Ellis, 1975). Since then a lot of different aquaponic systems were designed. Aquaponics has gained a lot more attention in recent years because of the growing attention for sustainability and rapid urbanization. The system is seen as one of the most efficient and sustainable animal protein production systems (Palm et al., 2018) and at the same time it is more efficient in terms of water use than other systems of conventional recirculation aquaculture systems (RAS) and hydroponics (Palm et al., 2018).
The general idea behind the system is quite easy. It basically combines two systems, aquaculture and hydroponics (König et al., 2018). Aquaculture is the farming of aquatic organisms (Palm et al., 2018). While hydroponics is a method of growing food using mineral nutrient solutions in water without soil (Al-Kodmany, Al-Kodmany, & Kheir, 2018). The water used in aquaculture is recirculated though the hydroponics system (“Aquaponics: How Does it Work? – Greengro Technologies,” n.d.). The water that is recirculated contains the waste from the fish which in return act as a nutrient source for the crop production in the hydroponic system (Mchunu, Lagerwall, & Senzanje, 2018). The plants clean the water by taking all useful nutrients (ammonium-N, Nitrate-N and phosphate-P). When the water is cleaned it will be circulated back to the fish, which than promotes the fish growth (Mchunu et al., 2018). The basics of an aquaponic system can be seen in figure 1.
Figure 1
Since the popularity for aquaponics has grown in recent years there also exist a broad variety of the different types and users of the system. Aquaponics can be categorized from hobby installations to commercial systems. The aim of this manuscript is to investigate the possibilities of aquaponics as a future commercial system. Therefore this manuscript looks further at the advantages, disadvantages and impacts of the system.
Impacts and challenges
Aquaponics has the potential to become a system to contribute to the rapid urbanization and help with the consequence of food security. Food security has become an increasingly important issue over the last few years in combination with the problem of rapid urbanization (Al-Kodmany et al., 2018). The population will increase while at the same time the shortage in food will continue to grow. For this reason the advantages and disadvantages of the possible urban faming solution of aquaponics will be highlighted in this section.
To highlight the impacts of aquaponics on sustainability this manuscript takes the three pillars of sustainability into account, the environmental, social and economic pillar. The environmental pillar is defined as the quality of not damaging the environment or reducing natural resources (Mchunu, Lagerwall, & Senzanje, 2017). With the economic pillar research refers to the use of various strategies for employing existing resources optimally (Mchunu et al., 2017). For the social pillar research looks at the needs of the present without compromising the ability of future generations to meet their own needs (Mchunu et al., 2017). To reach sustainability it is important to look at and balance the impacts of aquaponics on all three pillars as can be seen in figure 2.
Figure 2
Environmental
A lot of benefits are considered when talking about the aquaponic systems. Research shows several potential benefits for the environment (Shiun Lim et al., 2018). First of all the fuel emissions can be decreased. This is either achieved by the reduction of time food has to travel or by the reduction of fuel needed for the machines traditional farmers have to use in order to cultivate food. When aquaponics is used in urban areas the food does not have to travel so far anymore. On average food needs to travel for 1500 miles but with the use of urban farming the distance between food production and consumption is minimized (Al-Kodmany et al., 2018). Traditional farmers in America are using 20% of fossil fuel for machines for harvesting, seeding and plowing (Al-Kodmany et al., 2018). With aquaponics the amount needed for fossil fuel required for tractors can also be reduced.
Another environmental benefit on the use of aquaponics is the reuse and recycling of water resources (Shiun Lim et al., 2018). Research shows a growing global scarcity of water (Melgarejo-Moreno, López-Ortiz, & Fernández-Aracil, 2019). Aquaponics can help with this problem because the system tries to make an optimal use of the water resources. This is done by reusing the water and use the fish to clean the water.
Further the system provides an all year-round food supply without any interruption due to climate change, seasons or natural events. The system is also immune for weather changes and changing temperature (Al-Kodmany et al., 2018). Which makes it possible to produce food all year-round. Another benefit is the reduction of the need for packing the food which is normally needed for the long-distance transportation. Due to the short distance between the food production and food demand this is not necessary anymore. Research shows that it has also a potential to provide more food per space needed because the food can be produced in a vertical way instead of a horizontal way only (Al-Kodmany et al., 2018).
As can be seen there are some potential benefits for the environment. However since aquaponics is still not operating on a large scale further research is still needed to investigate the real benefits and potentials of aquaponics. As some researchers suggest that small scale aquaponics has potential to be sustainable, larger scale aquaponics can again lead to high use of fossil fuels and degraded water quality (Shiun Lim et al., 2018).
Economic
In terms of economic impacts aquaponics can bring public benefits and commodity outputs to urban areas. Building a aquaponic system in urban areas offers a lot of employment opportunities. A lot of different kind of professions are needed to make aquaponics in urban areas a success. Architects, engineering, scientist, farmers and economist are all needed to build a successful sustainable aquaponic system. For example, new careers within the fields biochemistry, biotechnology, construction and marketing can exists with the use of this technology (Al-Kodmany et al., 2018).
One of the economic challenges an aquaponic system faces is the cost of the labour and energy needed for the system. Aquaponics is a labour-intensive technology (Rizal et al., 2018). It is a necessary to continuous monitoring the aquaponics system for healthy growth of the fish and plant which lead to high labour and maintenance costs. This form of operations may not be economic beneficial for the system. To solve this challenge a lot of research has been done on optimizing the technology. For example monitoring the system could be done by applying a smart aquaponics system by continuously gathering data from aquaponic sensors (Kyaw & Ng, 2017). The system can then be controlled and if abnormalities occur the system can automatically solve the problem. This smart aquaponic system deals with the operational challenges however new challenges as high investing costs arise again (Kyaw & Ng, 2017).
Another economic challenge is the viability of the aquaponic system. The economic viability of the aquaponic system depends on achieving efficient and high yields on the products produced. This can be achieved by producing at a lowest cost possible and by improving the acceptance of the products by the consumers. After the system is implemented one of the biggest cost factors is the fish feed (Rizal et al., 2018). To keep the costs as low as possible to achieve higher yields research shows that this could be improved by using alternative fish feed or reducing the meals of the fish (Rizal et al., 2018). A main requirement for this aquaponic system to be an economically viable system is the acceptance of the products by consumers. Up until now only research has been done on the system and the growth of the products, but the acceptance of the products by consumers still needs to be studies in more detail to make a conclusion on the economically viability of the system (Rizal et al., 2018).
One of the greatest economic benefit of an aquaponic system is the creation of new job opportunities. On the other hand there are a few economical challenges addressed with the implementation system. First of all the investment costs may be too high at the moment (Shiun Lim et al., 2018). After the initial system is build there are also some doubts about the operating costs of the system, since aquaponics is a very labour-intensive technology. To see if the system is economic viable more research needs to be done on the acceptance of the products of the system. In the next chapter on the commercial implementation of the system this manuscript looks a little bit deeper into the current viability of the system on commercial scale.
Social
Aquaponics can also provide some social benefits. One research highlights the potential of aquaponics as a learning and educational facility for kids and adults (Shiun Lim et al., 2018). Aquaponics could for example be used as an educational tool in schools to learn children about the plants and the producing of food, but also for educating how to make public buildings and homes greener (Rizal et al., 2018).
Another social benefit could be that the aquaponic system helps bridge the gap between consumers and producers (Al-Kodmany et al., 2018). This integrated system creates a new social network between people form communities. Producers, farmers and consumers are all directly working together, farmers are selling their goods directly to the consumer which helps develop a social friendly community (Shiun Lim et al., 2018).
Also the health of citizens could be positively affected. The aquaponic system produces fresh local organic food. The products are not soil-based which means that the products are likely not affected by polluted soil or irrigation water. These benefits are positive for the health of the citizens. Another positive affect is bringing more nature to the city. According to research being close to the nature helps to reduce stress and has also a positive influence on the mental health (Al-Kodmany et al., 2018).
Overall the aquaponics system could positively affect the social aspects of citizens by producing fresh local food, better education and providing a new social community.
One of the social challenges that could be is the resistance of the system. Research shows that not everybody accepts the not traditional way of growing food (Al-Kodmany et al., 2018). When trying to make urban farming viability and implementing it on a commercial level people need to completely accept the system and the way of how food is growth. Only then the social impacts could be beneficial.
There is a promising future with a lot of potential benefits of the system on environmental, economical and social perspective. However also some challenges still remain. In the next chapter the manuscript looks at the commercial implementation of the systems and which factors still lack behind in implementing the system on a broader scale.
Commercial implementation
A lot of research has been done on aquaponics, but there is a limited focus on the commercial implementation of aquaponics (dos Santos, 2016). At the moment there is a research gap for the quantitative research to support the economically feasibility of aquaponic systems. This chapter tries to investigate the economical sustainability of an aquaponic system. This is done by looking at different aquaponic system categories and trying to make a conclusion about the commercial implementation of an aquaponic system.
Aquaponics can be categorized from mini-, hobby- and backyard installations to small-, semi- and large commercial systems. All types of systems have different variations and adaptions and all lead to a different outcome of economical sustainable. Research conducted by Palm et al. distinguish four categories of an aquaponic system: ‘open pond aquaponics’, ‘domestic aquaponics’, ‘demonstration aquaponics’ and ‘commercial aquaponics (intermediate or large-scale)’ (Palm et al., 2018). The four categories differ in size and production. Research shows that open pond aquaponics strongly contrast to the other systems. Open pond aquaponics are most of the time simple and small systems, the other aquaponic systems need more components and use more complex techniques (Palm et al., 2018).
As the aquaponic system increase in size and production the economical sustainability of the system also becomes more difficult to maintain and therefore influence the economic failure or success of the system (Palm et al., 2018). This because when the size and production increases towards commercial applications there is also a need for a wide range of skills and research. Therefore this research suggests that it is not viable yet to perform a aquaponic system on commercial scale (Palm et al., 2018).
Another research conducted by Shiun Lim et al. divide aquaponics systems in three different categories: ‘Home-based aquaponics (HA)’, Factory-based aquaponics (FA) and ‘Building-based aquaponics (BA) (Shiun Lim et al., 2018). Home-based aquaponics represents the small scale and self-sufficiency devices while factory-based and building-based aquaponics represents the more industrial medium and large scale food production. The research conducted a qualitative comparisons between the three kinds of aquaponic systems looking at the costs, production and sustainable benefits. The results of this research are summarized in figure 3 (Shiun Lim et al., 2018).
Figure 3
As can be seen in figure 3 the small scale aquaponic systems (HA) has low initial and annual costs whereas the medium (BA) and larger scale system (FA) has higher costs. The smaller system also has a smaller production and smaller sustainable benefits but according to this research the smaller scale aquaponic system is, as previous research also showed, the only system that is economically sustainable at the moment (Shiun Lim et al., 2018).
Another research looked at the economics of small-scale aquaponics in Hawai (Tokunaga, Tamaru, Ako, & Leung, 2015). This study showed that the small scale aquaponic companies are yielding a small profit and therefore gave insight in the economic feasibility of small-scale aquaponics systems. This gives potential for small scale commercial aquaponics to supply fish and vegetables for the local market and perhaps in the future this will lead to a more commercial application of aquaponics (Tokunaga et al., 2015).
The three different studies looked at the economical sustainability of an aquaponic system. All three studies made a difference in large scale and small scale systems. The first study looked at the economical sustainability of four different aquaponic system categories. Concluded was that when the size of the system increases it becomes more difficult to maintain economical sustainability. The other two studies confirmed this finding. They also found that the small scale aquaponic systems are currently yielding a small profit whereas large scale aquaponics currently are not.
However, there is still need for more developments to upscale the aquaponics projects so that it will be economical feasible and that the rates on the return on investment becoming higher. Therefore there is more quantitative research needed to reach parity with a traditional farm. This requires well-defined business models for determining the position of aquaponic systems in the specific markets. There is still a research gap to be considered before aquaponics can be implemented on commercial scale.
Conclusion
The aim of this manuscript was to highlight a concept of urban farming named, aquaponics. This concept combines two systems, aquaculture and hydroponics (König et al., 2018). The system has some great potential to become a commercial system which can help with the consequences of rapid urbanization. Impacts and challenges of this technology were described contributing to the three pillars of sustainability.
There exist some great potential benefits for the environment like reducing fuel emissions and recycling of water resources. Also according to the economical pillar the system could have great benefits and create new job opportunities. However there are still some challenges according to the investment costs, the economic viability of the system and the usage of the high labour-intensive technology. On the social scope the system could help improving the gap between producer and consumer and develop new social friendly communities. Also the aquaponic system produces fresh local organic food which could help with the health of the citizens. However a challenge the system is still facing is the acceptance of the technology, since it is not the traditional way of growing food.
Besides the potential and benefits aquaponics is showing there are still some challenges the system is facing. There is a limited focus on the commercial implementation of aquaponics. Research shows that if we want to implement aquaponics on a large scale there is more quantitative research needed to prove the economical sustainability of the system (Palm et al., 2018). For now aquaponics is only profitable on a small scale but there is a certain potential to implement aquaponics on a commercial level and eventually reach parity with a traditional farm.
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