Aquaponics

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Aquaponics system
Aquaponics system from the US organization Growing Power

Aquaponics refers to a process that combines techniques of rearing fish in aquaculture and the cultivation of useful plants using hydroponics . An aquaponics system is always a combination of a closed circuit system for fish production and a hydroponics system for growing plants, for example for vegetables and herbs.

The system works by using the excrement from fish farming as nutrients for plants . This is usually done automatically using pump systems. The nutrient input required for plant rearing is thus carried out through the fish feed.

Basics

Fish farming in aquaculture

Oreochromis niloticus

One component is fish breeding or keeping in tanks or (less often) in open ponds. Different fish species can be kept here depending on requirements and local climatic conditions. Cichlids from the genera Tilapia or Oreochromis are often used as particularly fast-growing and less demanding food fish, e.g. B. Oreochromis niloticus or Tilapia mariae .

These can also be fed with algae or plant-based food, but in temperate climates there is additional energy requirement for temperature control of the water. Fish and plants should be adjusted to the climate in the circulatory system.

Plant cultivation in hydroponics

The second component of an aquaponic system is plant cultivation in an inorganic substrate, similar to hydroponics, but without the pre-produced nutrient solution used there.

The useful plants usually grow in containers or growbeds that are filled with a substrate (e.g. non-floating expanded clay (density> 1) or gravel ) and are periodically flooded with the nutrient-rich water from the fish container. Cultivation with nutrient film technology or deep water culture is also possible.

The overflowing water is returned to the fish tank. In practice, water is not pumped out of the fish tank (otherwise the water level there will drop too much), but water is pumped from a water reservoir into the fish tank. The overflow then runs into the hydroponic system and the residual water or seepage water back into the water reservoir.

Bacteria as part of the system

The gravel bed at the bottom of the fish tank and the substrate of the plant container are covered with a biofilm of nitrifying bacteria , which convert the ammonium and ammonia of the fish excrement via the intermediate product nitrite into nitrate , which is ultimately available as a nutrient for the crops. So it is a technical application of the natural nitrogen cycle . Since nitrification is an aerobic process with high oxygen requirements, trickling through gravel filters is also used.

Separation of solids

Additional solids from fish excrement or biofilms can be separated and composted separately in an interposed sedimentation tank , but this is only rarely necessary in systems with a medium, as the medium itself provides good filtration.

Alternatively, worm composting is practiced in the plant substrate, in which the solids are broken down and kept in a cycle.

Differences from aquaculture

In aquaponics, the water does not have to be exchanged or additionally filtered, as it is available again in the quality required for fish farming in the biological cleaning processes described. This eliminates the ecological problem of over-fertilization of natural waters in the case of unregulated disposal of waste water from aquaculture . An imbalance between plants and fish can lead to overfertilization or nutrient deficiencies. In the event of over-fertilization (excessive nitrate content, which is harmful to fish), part of the water is exchanged as an immediate measure, which can be used to water other plants. Fresh water only needs to be supplied to compensate for the losses due to evaporation ( evapotranspiration ) and when biomass is extracted from the system.

history

The name aquaponics is a catchphrase from aquaculture and hydroponics. In 1985, McMurtry and Sanders developed a commercial aquaponic system under the name "Integrated Aqua-Vegeculture System", which processes the fish excrement from tilapia cichlids through algae and bacteria on sand filters for the cultivation of tomato plants. The basic research started by McMurtry and Sanders was further developed by the University of Virgin Island in a special research program for aquaponics-aquaculture.

In the meantime, aquaponic systems exist in small systems up to large, commercially used systems. They can be found all over the world and are used in both developed and developing countries.

Fish species

In addition to the tilapia cichlids that are kept around the world, fish such as

produced in systems adapted to their housing requirements.

Also, some species of Australian fish such as barramundi are bred in aquaponic cultures.

As a self-expanding chucks are up to 30% depending on the species Lemna used in the circulatory system.

Plant species

A large number of different plant species are cultivated in aquaponics facilities around the world. In Europe, plant species such as

grown under the parameters adapted for the respective plants . Available climatic conditions, which exist naturally or are artificially produced, open up or limit the species that can be successfully cultivated.

Networks, events & projects

Germany

In Germany there are several networks that promote developments in aquaponics. Across the country, aquaponists network through events such as the "Network Meeting Aquaponics North Rhine-Westphalia", which is organized by the associations "Aufbruch am Arrenberg e. V. "," die Urbanisten e. V. ”and the South Westphalia University of Applied Sciences as part of the“ Erasmus + ”project“ Urban Green Train ”. With the “Aufbruch am Arrenberg” project, an entire district is to become CO 2 -neutral by the year 2030 as the “ Arrenberg Climate Quarter ” . An urban farm with an "aquaponic farm " should "guarantee year-round continuous food production according to biological standards". To demonstrate an aquaponic system, the so-called farm box of the “Aufbruch am Arrenberg” association was installed on a parking lot. The "Bundesverband Aquaponik e. V. "is present at numerous events as a participant, exhibitor or otherwise. In addition, the federal association tries with an extensive system of contacts to mediate both scientific and economic partnerships and educational activities, which create new aquaponics projects of all kinds, especially projects for educational purposes. In the commercial production of food through aquaponics, there are the first start-ups (mainly in Berlin) that are doing this on a significant production scale.

Europe

The EU Aquaponics HUB is a program supported by COST (European Cooperation in Science and Technology) that promotes cooperation between European scientists and entrepreneurs in the field of aquaponics. Some German research institutes, universities and non-profit institutions such as the Federal Aquaponics Association are active in this network . The Europe-wide organization Association of Commercial Aquaponic Companies (ACAC) emerged from the “EU Aquaponics HUB” network, which is primarily geared towards scientific collaboration . The aim of ACAC is to support small businesses in the field of aquaponics across Europe, to promote the emergence of aquaponics in commercial agriculture and to establish an international quality standard through coordinated exchange.

International

The Aquaponics Association is an international, predominantly North American association with the aim of promoting the benefits of aquaponics through education and public relations. The organization's priorities are to spread aquaponics, to make consumers and authorities aware of the good health of aquaponics, and to dispel myths and rumors about aquaponics. The organization has developed a system for quality management, the so-called "Aquaponic GAP Standards". The organization also hosts the annual Putting Down Roots conference in Portland, Oregon.

See also

literature

Web links

Commons : Aquaponics  - collection of images, videos and audio files
  • ChemgaPedia: Aquaponics The structure and functionality of a modern aquaponics facility is described with many animations and photos. (German)
  • German aquaponics wiki at Wikia
  • Aquaponics - an exemplary system Video 14 minutes Arte
  • Bundesverband Aquaponik a network that is dedicated to the promotion and training in aquaponics with all its aspects, and activities primarily in German-speaking countries.
  • Frederike Gröner, Christin Höhne, Mathias Kunow, Werner Kloas: Aquaponic Model System - Technical instructions and potential research questions , IGB Leibniz Institute of Freshwater Ecology and Inland Fisheries, PDF file

Individual evidence

  1. ^ Aquaponics. ( Memento from January 29, 2010 in the Internet Archive ) In: Morning Star Fishermen. (English)
  2. ^ Canadian Farmed Tilapia. ( Memento of March 8, 2010 in the Internet Archive ) In: Canadian Aquaculture Industry Alliance. (English)
  3. ↑ MR McMurtry et al: Efficiency of Water Use of an Integrated Fish / Vegetable Co-Culture System. In: Journal of the World Aquaculture Society. 28, No. 4, 1997, p. 420, doi: 10.1111 / j.1749-7345.1997.tb00290.x .
  4. ↑ Aqua-vegeculture Systems.
  5. ^ Morris Villarroel, Ranka Junge, Tamas Komives, Bettina König, Ignacio Plaza, András Bittsánszky, Agnès Joly: Survey of Aquaponics in Europe . Ed .: Water; MDPI. Basel, Switzerland October 20, 2016, p. 4 .
  6. ↑ aquaponics.org.uk In: Aquaponics UK. (English)
  7. ↑ Felix Van Zyl: The Aquaponics Garden: Cultivating fish and plants in a closed cycle - step by step to your own system . tredition, 2017, ISBN 978-3-7439-8077-8 , pp. 40 ( google.de [accessed February 7, 2019]).
  8. ^ Morris Villarroel, Ranka Junge, Tamas Komives, Bettina König, Ignacio Plaza, András Bittsánszky, Agnès Joly: Survey of Aquaponics in Europe . Ed .: MDPI Journal "water". Basel, Switzerland October 20, 2016, p. 7 .
  9. ↑ 1st City Farm in Europe - Support the "Arrenberg Farm"! Retrieved November 17, 2017 .
  10. ↑ Eduard Urssu: Fish farming in the parking lot: "Aufbruch am Arrenberg" presents a closed nutrient-water cycle. In: Wuppertaler Rundschau. September 13, 2016, accessed November 17, 2017 .
  11. ↑ euaquaponicshub.com
  12. ^ The EU Aquaponics Hub - Realizing Sustainable Integrated Fish and Vegetable Production for the EU. COST, November 16, 2013, accessed on November 17, 2017 .
  13. ^ Sarah Milliken: Association of Commercial Aquaponics Companies (ACAC). January 13, 2017, accessed November 17, 2017 .
  14. ↑ Brian Filipowich: Putting down roots. the aquaponics association, November 14, 2017, accessed November 17, 2017 .