Economic Model Predictive Control of a Recirculating Aquaculture System

Abstract

The recirculating aquaculture systems (RAS) has been proposed to reduce the water consumption of commercial aquaculture. RAS removes organic and particulate waste from fish tank water while also aerating; as such the treated water can be recycled back into the tanks. In this work, we treat the RAS as a batch process such that economic model predictive control (EMPC) can be applied using a mechanistic process model. The EMPC, which considers fish production profits as well as material utility and electricity costs for RAS, is deployed for various water temperatures such that its effect on the fish growth and economics are quantified. Moreover, batch length is also determined through tracking of the process profit trajectory. The results show that the EMPC-operated RAS can substantially increase the fish sales price with time-varying control decisions. Moreover, the EMPC is shown to adjust its operating policy mid-batch to accommodate for temperature disturbances.