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The potential of aquaponics for the wellbeing of elderly citizens
Aquaponics may provide an optimal environment to reach several therapeutic goals in a variety of clients with cognitive and/or physical disabilities, and special population groups like the elderly, children, or developmentally challenged people. The therapeutic goals of health care professionals such as occupational therapists and physiotherapists are the promotion of and/or treatment for wellbeing. The primary goal of occupational therapy is to enable people to participate in the activities of everyday life.
· Aqu@teachThe most common pests and diseases
Identification of pests and diseases Proper identification of pests and diseases is important. Whether the pest is an insect, rodent, phytopathogenic fungus, or other organism, correct identification makes controlling it easier and more effective. A mistake in identification can lead to improper control tactics that cost time and money. It may also lead to unnecessary risks to people, to the fish, or to the environment. To identify a potential disease, one should follow the steps described in Figure 5 and 6.
· Aqu@teachThe grow beds
Water flow and positioning of the grow beds Water flow is the most important part of proper system design, and the exact positioning of the grow beds has a major impact on this. Therefore it should be considered carefully and, if possible, an expert should be consulted. The grow beds should be positioned after the biofilter and before the water is recirculated to the fish tank. Consider how the water will flow from the grow bed into the fish tank.
· Aqu@teachThe fish tank
The basic components to consider are fish tanks, the sludge removal unit, the biofilter, the sump, plant beds, pumps, and piping. The function, required materials, and location of each of these, and their interaction with other components, all need to be considered. The interaction among the components, for example, will determine the number of pumps that will be required. The fish tank will be the home of the fish for a relatively long period of time, so it should be chosen with care.
· Aqu@teachThe concept of integrated pest management (IPM)
Many national and intergovernmental bodies have firmly decided that the officially endorsed paradigm for crop protection is ‘integrated pest management’ (IPM). For example, a European Union (EU) Directive (The European Parliament and the Council of Europe 2009) has obliged all professional plant growers within the Union to apply the general principles of IPM since 2014. IPM is an ecosystem-based strategy that focuses on the long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and the use of resistant varieties (Tang et al.
· Aqu@teachThe biogeochemical cycles of major nutrients in aquaponics
The nitrogen cycle Nitrogen is an essential element for all living organisms and is the main nutrient of concern in aquaponics. It occurs in amino acids (parts of proteins), nucleic acids (DNA and RNA), and in the energy transfer molecule adenosine triphosphate (Pratt & Cornely 2014). As nitrogen occurs in many chemical forms, the nitrogen cycle is very complex (Figure 3). Figure 3: The general form of nitrogen cycle (Encyclopaedia Britannica)
· Aqu@teachThe biofilter
The biofilter is the heart of every recirculating aquaculture system. Fish health, and therefore economic success, depend on correct operation of the biofilter. High ammonia and nitrite levels in fish tanks can be caused by several factors. One of these can be poorly designed or sub-optimal operation of the biofilter (too small, not mixed evenly, nitrate levels too high, pH too low, intoxication of the biofilter by salt or medical treatment, aeration too low or too high, etc.
· Aqu@teachStarting to design an aquaponic system
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.
· Aqu@teachStacked horizontal beds
In this type of system, horizontal grow beds are stacked vertically in tiers. This arrangement means that in a greenhouse, only the upper bed will be facing direct natural light, and supplementary lighting needs to be provided for the lower beds, usually from lights attached to the base of the bed above. While in principle this means that the grow beds could be stacked as high as the greenhouse or production unit allows, in practice growing at height means that the system is more difficult to manage, requiring the use of scissor lifts for planting, maintenance and harvesting, and additional energy to pump the water to all levels.
· Aqu@teachSolids separation
The following decisions need to be made during the design stage: Is a separate solid removal step necessary? In systems with a low fish stocking rate, a media growing bed can remove solids and act as a biofilter. However, over time, clogging and anaerobic areas will occur as the amount of solids increases. What is the appropriate device for solids removal? Waste particles in the water can be of different sizes, which affects the technologies used to remove them.
· Aqu@teach