Experimental Study of Flows in Fish Tanks for Aquaponic Systems.

Aquaponics is the combination of hydroponics – growing of plants in water, and aquaculture – growing of fish. The plants benefit from the nutrients available in the fish waste water and help with filtering the water, which is recirculated back to the fish tank. Small-scale aquaponic systems are of particular interest for rural and developing locations as they can provide food security for local communities in a cost-effective way. The fish tank and pump have the most significant impact on the initial and operational costs of these systems. To address this, we have investigated the flow in a 2-meter X 2-meter square fish tank with rounded corners and two different inlet configurations. A Vectrino Acoustic Doppler Velocimeter was used to map the flow at three different depths. Detailed repeatability and uncertainty analysis were performed to ensure the validity of the data. Initial results suggest that the configuration with fewer inlets and lower flow rate resulted in similar velocity profiles compared to those obtained with the configuration with more inlets and higher flow rate. The next step in the research is investigating more inlet configurations with the goal of minimizing the power consumption of the pump, and hence decreasing the operational cost of the system.