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Starting to design an aquaponic system

· Aqu@teach

Do not be confused by the great variety of designs for aquaponic systems which you may encounter in the literature or by browsing the web. When planning and building an aquaponic system, it is necessary to follow the basic principles in order for the system to function properly. There are big differences between systems in terms of investment costs, maintenance and operating costs, reliability, health and safety, potential for fish and crop growth, and total workload. It is therefore necessary to define all these aspects during the design phase.

The design of a new aquaponic system should be based on your goals and requirements:

  • What is the purpose of the system? (food self-sufficiency, business, decoration, social impact, teaching)

  • How much space is available? A commercial system needs more than 1000 m2, while backyard aquaponics for self-sufficiency can be smaller

  • Where is the system going to be placed? If it will be outside, construction costs may be lower but more energy will be spent on heating. If it will be inside, more energy will be spent on lighting

  • How much time can be invested in the operation? Automatic regulation is expensive, while multiple daily checks are time consuming (although the fish have to be checked daily anyway)

  • Should I buy a ready-made kit or build my own? Several kit designs are available but they might not suit your goals. On the other hand, building requires knowledge, even though recycled materials can be used to reduce costs

  • When designing, consider all the activities in order to anticipate the routine procedures, maintenance, and how to deal with emergencies.

The design and construction of an aquaponic system follows a series of sequential steps: feasibility study and site selection, basic design, detailed design, construction site preparation, and construction. Basic design criteria have already been discussed in Chapter 2, so here we bypass this step and use the example from Chapter 2 as a template for detailed design. Table 1 summarizes the main steps involved in progressing from an idea for an aquaponic system to a fully operational system.

Table 1: Steps in the design and build of an aquaponic system

Feasibility study and site selection

In the feasibility study you check whether the site you plan to put the aquaponic system in has the basic needs to enable construction and operation. These needs cover space requirements, surface load, power availability and reliability, vehicular access, water quality and availability, cooling and heating possibilities, climate, sunlight etc. The feasibility study also includes the production planning of the site, so you need to know how many tanks will be required and with what water volume, the size of the plant cultivation area, and so on. These are the first things you need to know before the basic design process can start.

Basic design

In basic design you plan the basic dimensions of your system by following a step-by- step planning process (see [Chapter 2](https://https://learn.farmhub.ag/articles/)). You either start with the production area of vegetables and then design the fish rearing system based on the nutrient needs of the plants, or vice versa. At the end of basic design, you will have defined a general process flow diagram with the main components: production rates for fish and plants; water flow rates; fish tank volume, shape, and water level; solids removal dimensions; biofilter type, size, and shape; piping length and diameters; water flow speeds in different pipes; water levels. Basic design will reveal whether your production goals can be reached on the site you have chosen.

Detailed design

Detailed design uses the same design considerations as basic design, but goes into more detail. While in the previous step you were focusing only on the hydraulics and dimensions, you now also need to focus on the materials you will use, and choose the individual technical components, their power demand, backup power requirements, measurements and control units, and do a detailed design of all the hydraulic components (pipes, outlet screens, biofilter etc. etc.). Depending on the size of the project and the country you work in, detailed design will end with construction plans which either you execute yourself, or can be given to a construction company to execute. Planning the plumbing, electrical wiring, ventilation channels and walkways in a 3D model will help you ensure that the installation process will go smoothly. During detailed design you also need to have a good understanding of the construction material and construction techniques needed, so that there is sufficient space to mount the system.

Construction

The main goal during construction is to build the farm as quickly as possible, since having a construction site for a long time is normally very costly.

Operation start up procedures

The system needs to be filled with water and the following basic operational requirements will need to be tested before the fish are transferred to the system:

  • recirculation rate

  • leaks

  • water levels

  • air flows

  • oxygenation capacity

  • degassing capacity

  • system monitoring and emergency protocols

The next step will be the biological startup of the system, which has to be done 4-6 weeks before the first fish are added to the system. By this time, the SOPs (standard operating procedures) for running the system will need to be ready. Calculate at least 8 weeks from the end of construction until the first fish enter the system.

Copyright © Partners of the Aqu@teach Project. Aqu@teach is an Erasmus+ Strategic Partnership in Higher Education (2017-2020) led by the University of Greenwich, in collaboration with the Zurich University of Applied Sciences (Switzerland), the Technical University of Madrid (Spain), the University of Ljubljana and the Biotechnical Centre Naklo (Slovenia).

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