In a recirculating aquaculture system (RAS) with high stocking densities, CO2 tends to accumulate in the water to concentrations that can negatively affect both productivity and economics. Currently, it is a challenge to monitor and control the CO2 concentration in an RAS in real-time, due to inefficient monitoring methods.
Based on the original design published by Pfeiffer et al., 2011, a system will be developed capable of recording, storing, graphing, and delivering real-time relevant information for comprehensive monitoring of CO2 present in a recirculating aquaculture system using microcontrollers, sensors, cloud computing, and actuators, connected via the internet. The equipment will be mounted on an experimental structure simulating a desorption tower, using freshwater and gaseous CO2 injected through a diffuser stone to condition the water in a controlled manner. The devices will also provide information on salinity, temperature, dissolved oxygen, and pH in the water, as well as temperature and humidity levels in the gas effluent.
This data will form the basis for quantifying CO2 emissions into the atmosphere and its concentration in the water. This will enable the future implementation of actuators (pumps, blowers, solenoid valves) to automate control of an RAS, maintaining a CO2 concentration between 8 to 10 mg/l (suggested by the salmon industry) and using equipment that increases the demand for electrical energy only when necessary. In addition, it will provide the necessary knowledge to establish a potentially productive use of CO2 that is currently discarded, promoting a circular economy.