Designing Aquaponic Production Systems towards Integration into Greenhouse Farming

Abstract

Aquaponics is a sustainable method of food production, whereby aquaculture and hydroponics are combined in one circular system. A few aquaponics startup companies are emerging in Europe with a limited production area of a few hundred or a few thousand square meters, whereas hydroponics is a common practice in a commercially viable manner most often with production units of several hectares. In Iceland, greenhouse farmers operate on relatively small production units, often between 2000 and 5000 m2. The aim of the present study was, therefore, to develop and design aquaponic production systems towards integration into small greenhouse farming strengthening economic viability and sustainability. Since the local market in Iceland is small and import is relatively expensive due to the distance from other markets, the suitability of commercially available fish feed and the selection of plant species were assessed in relation to production efficiency and available market and resources. The effects of water flow on plant growth and on nutrient utilization in culture water were measured and evaluated. Four aquaponics test systems were designed, built and operated, and results were used to develop a pilot commercial aquaponics system implemented for greenhouse farming in Iceland. One of the test systems was a media filled flood and drain system and the other three were deep water culture systems. Tilapia (Oreochromis niloticus), one of the most popular fish in aquaculture, was reared in all systems, while different leafy greens and fruiting vegetables were grown in the hydroponics. The fish was fed with commercial aquaculture feed made for cod and charr. The feed conversion ratio (FCR) was used to assess the effectiveness of feed on fish growth. The FCR observed in this research was between 0.9 and 1.2, within the typical values for tilapia growth in aquaculture. The production of the leafy green plants (e.g., pak-choi) was approximately four times, by weight, that of the production of fish, a similar yield as shown in other researches in the field. The continuous rise of nitrate and phosphate concentrations in the aquaponic system indicated the potential to support even higher crop yield. Long daylength in the summer in Iceland is clearly beneficial for crop production in aquaponics. Based on the results, it is concluded that aquaponics can be a feasible opportunity for greenhouse farming at least to diversify the current business model. Not only can the fish provide an extra income but also the effluent from the aquaculture is easily used as fertilizer for the plants, thus the circular production system offers new innovative ideas for diversifying and value-adding the business further, for example into crayfish production and/or into educational and experience tourism.

Produtividade de híbridos de tomate cultivados em aquaponia associada em sistema tipo floating

“…O oxigênio dissolvido acompanhou a variação da condutividade elétrica, porém, com comportamento inverso, isso pelo fato da condutividade elétrica refletir maior quantidade de nutrientes na água, implicando em maior consumo de oxigênio (Danner et al, 2019).…”

“…As menores temperaturas registradas estiveram sempre no limite superior da faixa ótima. Na maior parte do período observado a temperatura da água esteve entre 25 e 30 ºC, o que, por outro lado, é uma faixa boa para as tilápias (Jordan et al, 2011;Danner et al, 2019).…”

“…Por se tratar de um ambiente simbiótico, deve haver um bom equilíbrio entre a quantidade de peixes e plantas no sistema, além de parâmetros como pH, temperatura e oxigenação, de forma que o ambiente seja favorável tanto para os peixes, quanto para as plantas (Rakocy et al, 2006;Danner et al, 2019). Nesse tipo de sistema, é difícil criar condições totalmente favoráveis para as plantas ou para os peixes.…”

Biocontrol of Phytopathogens under Aquaponics Systems

“…Aquaponics has been compared with aquaculture [2,7,8] and hydroponic [9][10][11][12] technologies in terms of production and profitability. Up to now, the research on aquaponics has been focused on sustainability [13][14][15], economic optimization [16][17][18], functional setup [19,20], stocking density [21,22], cultivation media [23,24], water recirculation [25,26], food safety [9,27], fish-plant pathogens [6,28] and beneficial microorganisms [29,30].…”

The Duckweed, <em>Lemna minor</em> Modulates Heavy Metal-induced Oxidative Stress in Nile Tilapia

“…Introduction of aquatic phytoremediation plant species and adsorbents should be performed in land management plans in order to reduce risks due to their contamination [22]. Therefore, plants represent an alternative remediation approach has escalated in the last few decades, [23][24][25][26][27][28][29].…”