Chapter 12 Aquaponics: Alternative Types and Approaches
12.8 Vermiponics and Aquaponics
It would be remiss in this chapter not to mention earthworms and their introduction into aquaponics, and thus this chapter concludes with a brief résumé of these detritivore invertebrates and their abilities to convert organic waste into fertilizer. It is said that worms and the way that they digest matter were of interest to Aristotle and Charles Darwin as well as the philosophers Pascal and Thoreau (Adhikary 2012) and they were protected by law under Cleopatra.
· Aquaponics Food Production Systems12.7 Digeponics
Anaerobic processing of purposely cultivated biomass, as well as residual plant material from agricultural activity, for biogas production is a well-established method. The bacterially indigestible digestate is returned to the fields as a fertilizer and for building humus. Whilst this process is widespread in agriculture, the application of this technology in horticulture is relatively new. Stoknes et al. (2016) claim that within the ‘Food to waste to food’ (F2W2F) project, an efficient method for the utilization of digestate as substrate and fertilizer has been developed for the first time.
· Aquaponics Food Production Systems12.6 Biofloc Technology (BFT) Applied for Aquaponics
12.6.1 Introduction Biofloc technology (BFT) is considered the new ‘blue revolution’ in aquaculture (Stokstad 2010) since nutrients can be continuously recycled and reused in the culture medium, benefited by the in situ microorganism production and by the minimum or zero water exchange (Avnimelech 2015). These approaches might face some serious challenges in the sector such as competition for land and water and the effluents discharged to the environment which contain excess of organic matter, nitrogenous compounds and other toxic metabolites.
· Aquaponics Food Production Systems12.5 Vertical Aquaponics
12.5.1 Introduction Whilst aquaponics can be seen as part of a global solution to increase food production in more sustainable and productive ways and where growing more food in urban areas is now recognized as part of the solution to food security and a global food crisis (Konig et al. 2016), aquaponic systems can themselves become more productive and sustainable by adopting alternative growing technologies and learning from emerging technologies such as vertical farming and living walls (Khandaker and Kotzen 2018).
· Aquaponics Food Production Systems12.4 Maraponics and Haloponics
Although freshwater aquaponics is the most widely described and practiced aquaponic technique, resources of freshwater for food production (agriculture and aquaculture) are becoming increasingly limited and soil salinity is progressively increasing in many parts of the world (Turcios and Papenbrock 2014). This has led to an increased interest and/or move towards alternative water sources (e.g. brackish to highly saline water as well as seawater) and the use of euryhaline or saltwater fish, halophytic plants, seaweed and low salt-tolerant glycophytes (Joesting et al.
· Aquaponics Food Production Systems12.3 Algaeponics
12.3.1 Background Microalgae are unicellular photoautotrophs (ranging from 0.2 μm up to 100 μm) and are classified in various taxonomic groups. Microalgae can be found in most environments but are mostly found in aquatic environments. Phytoplankton are responsible for over 45% of world’s primary production as well as generating over 50% of atmospheric Osub2/sub. In general, there is no major difference in photosynthesis of microalgae and higher plants (Deppeler et al.
· Aquaponics Food Production Systems12.2 Aeroponics
12.2.1 Background The US National Aeronautics and Space Administration (NASA) describes aeroponics as the process of growing plants suspended in air without soil or media providing clean, efficient, and rapid food production. NASA furthermore notes that crops can be planted and harvested year-round without interruption, and without contamination from soil, pesticides, and residue and that aeroponic systems also reduce water usage by 98%, fertilizer usage by 60% percent, and eliminate pesticide usage altogether.
· Aquaponics Food Production Systems12.1 Introduction
This chapter discusses a number of key allied and alternative technologies that either expand or have the potential to expand the functionality/productivity of aquaponic systems or are associated/stand-alone technologies that can be linked to aquaponics. The creation and development of these systems have at their core the ability, amongst other things, to increase production, reduce waste and energy and in most cases reduce water usage. Unlike aquaponics, which may be seen to be in a mid/teenage stage of development, the novel approaches discussed below are in their infancy.
· Aquaponics Food Production Systems