The Need for Systems Design for Robust Aquaponic Systems in the Urban Environment

Abstract

Aquaponics -the co-production of fish and plant products -is gaining interest both by entrepreneurs and researchers. This article evaluates both the technical setup as well as the economic potential of aquaponic systems and is aimed at identifying relevant knowledge questions for further improvements. Using system requirements for hydroponic systems and aquaculture, the aquaponic system was compared to a typical Dutch rockwool system. Aquaponics was found to be an improvement on current practices when using Deep Flow Technique (cultivation in a flowing thick water layer), resulting in better nutrient availability for the plants and re-use of nitrate. However, the technical challenges of the direct linkage between the two production systems in terms of needed technology and disease management was found to make the total system suboptimal when compared to conventional practices. The technological advantages of efficiency in use of land and energy and re-use of nutrients were found to be a marginal cost reduction of 1.2%. The article concludes that the added value of aquaponics can be found in the total business concept of producing in an urban environment with direct relationship with consumers. Further improvement of aquaponics can be found in improved disease management of the system -through management or improved design. INTRODUCTIONUrban farming creates value through the production of small scale, sustainable and local produce, often in direct interaction with the consumer. Sustainability is achieved through the re-use of waste streams of water, nutrients and energy by combining different (agricultural) activities. A sustainable, applicable and small scale system for such re-use is the combination of fish production in Recirculating Aquaculture Systems (RAS) and horticulture -so called Aquaponics. For professional aquaponics to take off in Europe the production systems need to have added value, be robust and easy to use. Research has focused on plant aspects (nutrients and quality; Pantanella et al., 2012) and fish production (densities, diseases) and technology. But less on the business rationale and design structure. However, designing for such complex systems requires a systematic approach, where an analysis of functions and quantified requirements is used to select and improve on the technical lay-out. Functions and requirements are based on insights and needs from both researchers and experts as well as users and stakeholders -in the case of urban farming city planners and the general public. However, such analysis has only recently been developed for both hydroponic systems and aquaculture, but not for the combination of the two nor the application in an urban setting. This paper describes the system requirements for both aquaculture as well as horticulture that would apply for aquaponics in an urban environment.

Challenges of Sustainable and Commercial Aquaponics

“…Vermeulen and Kamstra [22] report only a marginal cost reduction for environmental benefits of nutrient reuse and energy efficiency when aquaponics is compared to RAS and hydroponics run separately. However, this study did not take socio-ecological factors into account, such as operating in a resource (e.g., phosphorous, water) limited world.…”

“…The challenges of pest and disease management is another aspect that needs further improvement [22]. Aquaponic systems are characterized by a broader range of microflora than conventional hydroponic systems, especially because the breeding of fish and biofiltration occurs in the same water loop.…”

“…Although Vermeulen and Kamstra [22] state that the actual perceived environmental benefits of nutrient reuse, energy efficiency and land use seem only marginally cost-effective, the aspects of possible differences in product quality and societal value are not necessarily reflected in business costs. Also, the use and cost of fertilizers in hydroponic production systems has an increasing importance, as fertilizer costs lie between 5% and 10% of the overall costs, and scarce fossil fuels are required in their manufacture [121].…”

“…Although preliminary research has shown that developed aquaponic system components are not yet fully realized in view of either cost effectiveness or technical capabilities [21,22], the aquaponics concept is promising to contribute to both global and urban sustainable food production and should at the same time diminish pollution and need for resources. In order to meet the goal of establishing large-scale eco-efficient and economically viable aquaponic farming projects, this paper reviews the technical and socio-ecological developments that have been undertaken to date and demonstrates which aspects still need to be addressed.…”

Opportunities and Challenges of Multi-Loop Aquaponic Systems

“…In this study, and in line with Nichols and Savidov (2012) as well as Seawright (1998) aquaponics can be defined as a multi-trophic food production system comprising of a recirculating aquaculture system (RAS) and hydroponic (HP) elements (Figure 1.1). In these one-loop aquaponic systems, RAS-derived nutrient-rich water from the HP element is directly constantly directed to the hydroponic unit providing the plants with essential nutrients for plant growth instead of being discharged (Liang and Chien, 2013;Vermeulen and Kamstra, 2013). In one-loop aquaponic systems, the partly demineralized water is led back to the RAS (Graber and Junge, 2009;Licamele, 2009;Rakocy et al, 2006).…”