Decoupled Aquaponics

  • Decoupled Aquaponics

    Whether decoupled Aquaponics (DAPS: Decoupled Aquaponics System) has a general advantage over conventional recirculating aquaponics systems is much debated on the internet and in academia. Finding this out has been our goal over the last few years and led to the publication "Navigating Decoupled Aquaponics Systems: A system dynamics design approach ". Following the KISS principle (Keep it simple, stupid!), I will briefly outline the main points of the publication and discuss them a bit in non-scientific jargon (without the abstract of the paper).
     
     
    DAPS Decoupled Aquaponics System ( Entkoppeltes Aquaponiksystem )
    HP Hydroponik
    RAS Rezirkulierendes Aquakultur System

     

     

     

    Abstract

    The classic working principle of aquaponics is to supply a hydroponic plant culture unit with nutrient-rich aquaculture water, which in turn purifies the water that is returned to the aquaculture tanks. A known drawback is that a compromise away from optimal growing conditions for plants and fish must be achieved to produce both crops and fish under the same environmental conditions. The aim of this study was to develop a theoretical concept of a decoupled aquaponics system (DAPS) and predict water, nutrient (N and P), fish, sludge and plant values.

    flow ras daps smallThis was addressed by developing a dynamic aquaponic system model using inputs from data in the literature covering aquaculture, hydroponics and sludge treatment. The results of the model showed the dependence of aquaculture water quality on hydroponic evapotranspiration rate. This result can be explained by the fact that DAPS is based on one-way flows. These one-way flows lead to accumulations of remineralised nutrients in the hydroponic component, which ensure optimal conditions for the plants. The study also suggests sizing the cropping area based on P availability in the hydroponic component, as P is a depletable resource and has been identified as one of the most important limiting factors for plant growth.

     

    Decoupled aquaponics

    Although many aquaponics systems are designed and operated as recirculating systems, commercial growers and researchers are expanding this initial aquaponics system design to include independent control over each system unit (i.e. RAS, hydroponics and nutrient recovery through sludge remineralisation: recirculated aquaculture systems).
    Decoupled aquaponics systems (DAPS) are systems in which fish, plants and, where appropriate, remineralisation are integrated as separate functional units consisting of individual water circuits that can be controlled independently. The difference between the concepts of one-loop and multi-loop (i.e. decoupled) aquaponics systems can be seen in Figures 1 and 2. In the context of recycling all nutrients entering the system, decoupled aquaponics can be seen as a preferred option as they avoid additional discharge.

     small recirc

    Abb. 1 - The one-loop aquaponics system is the traditional aquaponics approach. Instead of supplementing the hydroponic part with fertiliser, both components are exposed to quite similar conditions

     

    small decoupled

    Abb. 2 - In contrast to a single-loop aquaponics system, a multi-loop aquaponics system aims to create optimal conditions for both fish and plants. In this case, the fish sludge coming from the RAS is remineralised and fed to the hydroponics.

     

    Figure 3 shows a process flow drawing of a basic DAPS layout. Please note - this is only an example and can be adapted in a modular way. The blue tags in the figure include the RAS component, the green tags include the hydroponic component and the red tags include the remineralisation components. The sequence of the components is represented numerically in the tags and refers to the vertical direction in which the flow must move.
    This means that high numbers refer to high positioning and low numbers to low positioning.
     

    entkoppelte aquaponik

    Während RAS (Rezirkulierten AquakulturSysteme) und Hydroponik seit Jahrzehnten Gegenstand der Forschung sind, steckt die Remineralisierung von Fischschlamm noch in den Kinderschuhen. In der Abhandlung haben wir die Vor- und Nachteile der aeroben Vor- und Nachbehandlung der anaeroben Vergärung diskutiert, derzeit untersuchen wir jedoch die Leistung der reinen anaeroben Vergärung. Wir werden Sie auf dieser Website über unsere Ergebnisse auf dem Laufenden halten.

    Leider müssen wir alle enttäuschen, die sich dafür begeistert haben, ein entkoppeltes Aquaponik-System in ihrem Garten zu bauen. Entkoppelte Aquaponiksysteme erfordern viel Steuerungstechnik und sind nur sinnvoll, wenn man bereit ist, hohe Nährlösungen in der Hydrokultureinheit zu erzielen. Außerdem ist die Dimensionierung des Systems im Vergleich zur Dimensionierung herkömmlicher Systeme mit einer Schleife viel komplexer. Die Ermittlung der erforderlichen Evapotranspirationsrate der hydroponischen Pflanzen, die erforderlich ist, um eine Akkumulation von Stickstoffformen im RAS zu vermeiden, erhöht die Komplexität zusätzlich. Folglich sind diese Art von Systemen am besten für kommerzielle Systeme im großen Maßstab geeignet, insbesondere wegen ihrer Fähigkeit, mit kommerziellen Hydrokultursystemen zu konkurrieren.

     

    Growth benefits

    The sweet spot of aquaponics for most people is the sustainable approach as well as the symbiotic effect of the RAS water on the plants and vice versa. From a commercial point of view, you cannot convince farmers with these arguments, even though they might be valid. In recent experiments, we observed growth benefits from decoupled aquaponics systems. We observed a 39 % increase in plant growth compared to a pure hydroponic control nutrient solution when supplementing the hydroponic component with additional fertiliser. Furthermore, we were able to show that anaerobic digestate also increased plant growth. At the moment, it seems that both the RAS water and the digestate contain plant growth-promoting rhizobacteria (PGPR), which could promote plant growth. We are currently planning further experiments on this topic and will also try to identify and isolate some of these PGPR.
     

    Sensitive fish species

    In the article we explained why decoupled aquaponics is suitable for sensitive fish species. We found that the use of artificial greenhouse light leads to lower fluctuations in RAS nutrient concentrations because plant evapotranspiration is more constant. The extent to which artificial lighting pays off needs to be investigated in a harvest- and fish-dependent economic evaluation.

     

     

    Hybrid backyard approach

    The hybrid decoupled system is a combination of the one-loop and decoupled approaches (Fig. 4). Home and garden growers who still want to get into decoupled aquaponics may want to try this approach. Resizing an existing system would be obsolete, as the remineralised sludge would serve as a source of nutrients for the additional culture beds. 

    hybrid system

    Abb. 4 - Hybrides entkoppeltes Aquaponic-System. Ein Ansatz für Heimgärtner?

     

    Conclusion

    We believe that decoupled aquaponics systems have the potential to achieve similar or even higher performance than hydroponic production. We know this is a bold statement, but recent observations support these assumptions. However, whether these growth advantages of DAPS over hydroponics can still be observed under perfect growing conditions (i.e. optimal climate control, light intensity and CO2 addition) remains to be clarified. The decisive advantage, however, is the sustainable approach, which aims to recycle everything that enters the system. This aspect alone is a full justification for decoupled aquaponics.
    Regarding the remineralisation component, there is a need for further research on its remineralisation performance depending on different hydraulic retention times (HRT) and sludge retention times (SRT). In summary, while technical research in this area is important, additional geographically dependent follow-up studies are needed that address the economically feasible size of DAPS as well as comparison with equivalent hydroponic systems.

     

    Sources:
     
    This article is based on excerpts, additions, summaries and translations of various scientific publications. Among others, the following were used:
     

    MDPI and ACS Style
    Goddek, S.; Espinal, C.A.; Delaide, B.; Jijakli, M.H.; Schmautz, Z.; Wuertz, S.; Keesman, K.J. Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach. Water 2016, 8, 303. https://doi.org/10.3390/w8070303

    AMA Style
    Goddek S, Espinal CA, Delaide B, Jijakli MH, Schmautz Z, Wuertz S, Keesman KJ. Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach. Water. 2016; 8(7):303. https://doi.org/10.3390/w8070303

    Chicago/Turabian Style
    Goddek, Simon, Carlos Alberto Espinal, Boris Delaide, Mohamed Haissam Jijakli, Zala Schmautz, Sven Wuertz, and Karel J. Keesman. 2016. "Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach" Water 8, no. 7: 303. https://doi.org/10.3390/w8070303

    Decoupled Aquaponics – The Future of Food Growing?

    http://www.developonics.com/2016/07/decoupled-aquaponics/

    Navigating towards Decoupled Aquaponic Systems: A System Dynamics Design Approach
    https://www.mdpi.com/2073-4441/8/7/303/htm
    Kontext: 
     ID: 398

  • Ecoponics Introduction

    water insects biodiversity heritage cc
    First, some very positive aspects of ecoponics. It offers numerous advantages that make it an attractive option for sustainable agriculture.
    • Environmental friendliness: By avoiding synthetic fertilizers and pesticides, ecoponics reduces environmental pollution and conserves natural resources.
    • Resource efficiency: Ecoponic systems use water and nutrients efficiently, resulting in significant reductions in water consumption and better use of resources.
    • Healthy food production: The use of organic nutrients leads to healthier plants and therefore higher quality and more nutritious food.
    • Promoting biodiversity: By integrating different plant species and promoting ecologically beneficial organisms, ecoponics contributes to the preservation and promotion of biodiversity.
    • Sustainability: Ecoponics supports sustainable agricultural practices that contribute to the long-term conservation of natural ecosystems.
    • Reducing waste: Using organic waste as a source of nutrients and reusing water minimizes waste.
    • Independence from soil: Ecoponic systems can operate independently of soil quality, allowing cultivation in urban areas and on infertile soils.
     
    These advantages make ecoponics a promising method for sustainable and environmentally friendly food production.
    However, when implementing ecoponics, various challenges can arise, which can be both technical and ecological in nature.
    Here are some of the common problems.
     
     

    Problems in implementing ecoponics

    Nutrient management
    • Imbalance: It can be difficult to provide the correct amounts and ratios of organic nutrients because they are more variable than synthetic fertilizers.
    • Deficiency symptoms: Organic nutrients must be in forms that are available to plants, which is supported by microbiological processes that do not always occur consistently.
     
    Water quality and management
    • Contaminants: Organic nutrients can increase the risk of contaminants in the water system, which can lead to algae growth and blockages.
    • Microbial contamination: Improper handling of organic material can lead to the proliferation of undesirable microorganisms that can cause plant diseases.
     
    Pest and disease control
    • Biological pest control: The use of natural enemies and biological preparations can be less predictable and more effective than chemical agents.
    • Diseases: Organic systems may be more susceptible to certain plant diseases that are difficult to control.
     
    Technical challenges
    • System complexity: Ecoponic systems are often more complex than traditional hydroponic systems and require a higher level of knowledge and technical expertise.
    • Maintenance: The systems require regular maintenance and monitoring to ensure optimal functioning.
     
    Cost efficiency
    • Initial costs: The initial investment to set up an ecoponic system can be high, especially when sustainable and energy-efficient technologies are integrated.
    • Running costs: Running costs for maintaining biological systems and obtaining organic nutrients can also be high.
     
    Education and Training
    • Expertise: There is a need for specialized knowledge and training to operate the system effectively and solve problems.
    • Experience: The lack of widespread experience and best practices can make implementation difficult.
     
    Environmental factors
    • Locally adapted solutions: Each region has different climatic and ecological conditions that require tailor-made solutions.
    • Availability of resources: The availability of high-quality organic materials may vary regionally and influence implementation.
     
    These challenges require careful planning, continuous monitoring and adjustment of systems as well as good training of operators to ensure successful implementation of ecoponics.
     
     

    Here are some keywords about ecoponics and its implementation

    1. Organic nutrients
    - Compost tea
    - Worm compost extract
    - Plant extracts
    - Fermented organic matter
     
    2. Sustainable resource management
    - water recycling
    - circular economy
    - resource efficiency
    - rainwater use
     
    3. Biodiversity and plant health
    - Mixed cultures
    - Biodiversity promotion
    - Companion planting (plant communities)
    - Ecological beneficial organisms
     
    4. Energy efficiency
    - Renewable energies (solar, wind)
    - Energy-saving lighting (LED)
    - Energy management
    - Heat recovery systems
     
    5. Biological pest control
    - Promotion of beneficial organisms
    - Biological preparations
    - Integrated plant protection (IPM)
    - Plant extracts against pests
     
    6. System design and construction
    - Vertical farming
    - Modularity
    - Automation and sensors
    - Substrate selection (e.g. coconut fibres, peat moss)
     
    7. Sustainable practices
    - Permaculture principles
    - Zero waste principles
    - Circular systems
    - Environmental impact assessment
     
    8. Community and Education
    - Community Gardens
    - Educational Programs
    - Research and Development
    - Public Relations
     
    Image: CC, Public Domain, Biodiversity Heritage Library, https://www.flickr.com/photos/biodivlibrary/
    Context: 
    ID: 598

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