Technological innovations for the use of biofloc systems in decoupled aquaponics

Abstract

Biofloc technology (BFT) is characterized as an aquaculture system with minimal or no water exchange, with high storage densities, sustained by the formation of a microbial community which, beyond maintaining suitable water quality to produce cultivated aquatic organisms, serves as food supplement for them. However, this system can occasionally generate larger concentrations of nutrients in the cultivation water. In order to maximize the system and solve this matter, the integration of BFT with the production of vegetables in aquaponic system has been investigated. Nevertheless, previous reports of the integration of both systems in a connected design showed problems with the handling of the microbial flakes. This way, looking for technological innovations such as, for example, the adoption of decoupled systems (DAPS) with the addition of mineralizers, can be an alternative. Added to that, the possibility of reducing the crude protein (CP) levels in the diet, due to the nutritional supplementation supplied by the BFT to the fish, could result in reduced costs and improved nutrient balance for plants. Based on these premises, the objective of this project is to evaluate the efficiency of the use of biofloc technology to produce Nile tilapia and lettuce in a decoupled aquaponic system. Thus, the present proposal will have three stages: the 1st and 2nd stages (experimental) will evaluate, respectively, the effect of diets containing different levels of CP in the production of tilapia and lettuce in DAPS using BFT and the mineralization of effluents of the BFT to produce lettuce in DAPS; and the 3rd stage (theoretical) will indicate a theoretical layout of the system proposed through the use of mathematical modeling. In summary, this project envisions technological innovation for fish and vegetable production in more productive and less polluting systems.