Aquaponic: The process
Aquaponics is a process that combines raising fish in an aquaculture with growing plants in hydroponics. There are different approaches to getting the nutrients to the plants.
We offer control systems for the automatic management of your aquaponics and hydroponics system. Our offer ranges from systems that only serve documentation purposes to fully autonomous system control.
Aquaponics as well as hydroponics systems are always part of a closed cycle. Aquaponics, for fish production, always includes a hydroponic system for plant cultivation. The system works by using the excreta from the fish farming as nutrients for the plants. This is done automatically in our systems via dosing systems. Through an appropriate control of the nutrient supply - which is optimised for the respective selected plant species and the development phase. The closed cycle results in well over 90% of the necessary nutrients, i.e. the investments, actually being contained in the two end products (vegetables & fish).
In contrast to soil-based planting, the following advantages result
- High yield: 500m2 yield up to 8 tons of fish and 16 tons of tomatoes per year.
- Minimal space requirement: profitability from 500 m2
- Independence from weather: year-round operation and yield
- Independence from precipitation: closed cycle
- Very low water consumption
- No use of pesticides
- No use of herbicides
- No use of medicines
- No damage to groundwater: closed cycle
Next article: What is aquaponics?
Situation, market demand and development
Biochemical flow boundaries that limit food supply are more stringent than climate change (Steffen et al. 2015, see figure below). In addition to nutrient recycling, dietary changes and waste reduction are essential to change current production (Conijn et al. 2018; Kahiluoto et al. 2014). Therefore, a major challenge is to shift the growth-oriented economic model to a balanced ecological economic paradigm - replacing infinite growth with sustainable development (Manelli 2016).
To achieve a balanced, more feasible and sustainable situation, innovative and ecological farming systems are needed so that trade-offs between immediate human needs can be balanced while at the same time ensuring the capacity of the biosphere to provide the necessary goods and services (Ehrlich and Harte 2015).
In this context, aquaponics (aquaculture + hydroponics) has been identified as an agricultural approach that can help achieve both planetary boundaries (see figure below) and sustainable development goals through nutrient and waste recycling, especially in arid regions or areas with non-arable soils (Goddek and Körner 2019; Appelbaum and Kotzen 2016; Kotzen and Appelbaum 2010).
Aquaponics is also seen as a solution to the use of marginal land in urban areas for near-market food production. At a time of "technology for backyards" (Bernstein 2011), aquaponics is now rapidly moving into industrial production as technical improvements in design and practice have significantly increased production capacity and production efficiency. One such area of development is coupled and decoupled aquaponics.
Traditional designs for single-loop aquaponics systems include both aquaculture and hydroponics units with water circulating between them. In such traditional systems, it is necessary to compromise on the conditions of the two subsystems in terms of pH, temperature and nutrient concentration (Goddek et al. 2015; Kloas et al. 2015, chapter 7).
A decoupled aquaponics system can reduce the need for compromise by separating the components, allowing conditions in each subsystem to be optimised.
It is precisely the problem of the costly transport
(from the region for the region) is increasingly becoming an environmental and cost problem in cities.
Initial experiments such as the cultivation of herbs in hydroponic systems, which can be seen in the first supermarkets and retail markets, illustrate the potential with the effect of cost reduction, through savings on transport and storage, and at the same time the gain of customer acceptance and their interest in the problem of future supply, since the herbs in these systems can be picked on site by the customers themselves.
The picture shows a plant in a supermarket of the Edeka chain of the company Infarm / Berlin.
According to the World Wild Fund for Nature (WWF), agriculture and processing account for about 70 percent of global freshwater consumption. In contrast, aquaponics enables food production with a 50 to 90 percent reduction in water consumption: 50 percent is saved with the old single-loop systems - simply because of the double use of water.
A dual-circuit system with water recovery even achieves a saving of about 90 percent. In this production system, fresh water only has to compensate for losses due to evaporation and the removal of biomass from the system.
Available resources for nutrition
Due to the resource situation, a rethink of food supply is inevitable. The current status of control variables for seven of the planetary boundaries as described by Steffen et al.(2015) can be seen in the graph above.
The green zone is the safe operating zone, the yellow zone represents the zone of uncertainty (increasing risk), the red zone is a high risk zone, and the grey zone boundaries are those that have not yet been quantified. The variables outlined in blue (i.e. land system change, freshwater use and biochemical fluxes) show the planetary boundaries on which aquaponics can have a positive impact.
This graph clearly shows that the "limits to growth" (Club of Rome, 1972) have already been reached. For traditional agriculture, not least due to the leaching of soils by various chemicals (such as glyphosate, see study by BUND, 2013), a considerable loss of yield can already be observed - at least where the use of this chemical is still permitted.
Further information and figures
Fertiliser use in German agriculture has already exceeded the limit of 200 tonnes per hectare per year.
Yields in organic farming:
Income costing in crop production:
Yields in aquaponics:
Literature and references
Bernstein S (2011) Aquaponic gardening: a step-by-step guide to raising vegetables and fish together. New Society Publishers, Gabriola Island
Conijn JG, Bindraban PS, Schröder JJ, Jongschaap REE (2018) Can our global food system meet food demand within planetary boundaries? Agric Ecosyst Environ 251:244-256. https://doi.org/ 10.1016/J.AGEE.2017.06.001
Ehrlich PR, Harte J (2015) Opinion: to feed the world in 2050 will require a global revolution. Proc Natl Acad Sci U S A 112:14743-14744. https://doi.org/10.1073/pnas.1519841112
Emerenciano M, Carneiro P, Lapa M, Lapa K, Delaide B, Goddek S (2017) Mineralizacão de sólidos. Aquac Bras:21-26
Goddek S (2017) Opportunities and challenges of multi-loop aquaponic systems. Wageningen University, Wageningen. https://doi.org/10.18174/412236
Goddek S, Keesman KJ (2018) The necessity of desalination technology for designing and sizing multi-loop aquaponics systems. Desalination 428:76-85. https://doi.org/10.1016/j.desal.2017. 11.024
Goddek S, Körner O (2019) A fully integrated simulation model of multi-loop aquaponics: a case study for system sizing in different environments. Agric Syst 171:143-154. https://doi.org/10. 1016/j.agsy.2019.01.010
Kotzen B, Appelbaum S (2010) An investigation of aquaponics using brackish water resources in the Negev desert. J Appl Aquac 22:297-320. https://doi.org/10.1080/10454438.2010.527571
Manelli A (2016) New paradigms for a sustainable well-being. Agric Sci Procedia 8:617-627. https://doi.org/10.1016/J.AASPRO.2016.02.084
Monsees H, Keitel J, Kloas W, Wuertz S (2015) Potential reuse of aquacultural waste for nutrient solutions in aquaponics. In: Proc of Aquaculture Europe. Rotterdam, The Netherlands
Steffen W, Richardson K, Rockström J, Cornell SE, Fetzer I, Bennett EM, Biggs R, Carpenter SR, de Vries W, de Wit CA, Folke C, Gerten D, Heinke J, Mace GM, Persson LM, Ramanathan V, Reyers B, Sörlin S (2015) Planetary boundaries: guiding human development on a changing planet. Science 347(80):736
Federal glyphosate study
Data Bridge Market Research
Aquaponics Market Share Trends 2022 Global Growth Challenges, Opportunities and Regional Segmentation Forecast to 2024:
Dr. Olaf Zinke, agrarheute from 24.06.2021