Simulation of Ca2+ and K+ concentrations in the nutrient solution of an aquaponic system

The application of aquaponic systems is closely related to the question if nutrient demand of crops can be covered by fish effluents. In this study, the flow of potassium and calcium macronutrients into a pilot-scale aquaponic system was studied. For this purpose, a simulation model was developed to assess the concentration of macronutrients in the main parts of the system. The main parts of the system are the fish tanks and the main aquaculture system buffer tank, the hydroponic head and the crop fertigation solution tank, the crop substrate, and the crop drainage tank. To validate the simulation model, measurements were performed in the pilot aquaponic system of the University of Thessaly in Volos, Greece. Basil plants were irrigated with fish effluent from tilapia after pH adjustment. The drainage solution from the crop was returned to the aquaculture system so that the system was completely closed. The measured nutrient concentrations were compared with the corresponding simulated data. The model predicted with fair accuracy the potassium and calcium concentrations for the total experimental period. The model is extended to the rest of the macronutrients sot that is could be finally used for the design and management of aquaponic systems. © 2022, VDI Verlag GMBH. All rights reserved.