Design and Environmental Analysis of an Aquaponics System Coupled with Photovoltaic Unit for Food Production and Reuse of Nutrients from Wastewater: A Life Cycle Assessment Study

Aquaponics consists of the combination of hydroponics and aquaculture within a closed loop, being a promising technology for food production and wastewater treatment in the context of the circular economy. This technology is less energy-intensive, environmentally friendly, and consumes less water. In addition, the wastewater produced by fish, rich in nutrients, can be used to grow a wide variety of plants, which avoids further treatments for nutrient removal. Although aquaponics presents advantages from an environmental point of view with regard to other technologies, its sustainability must be analyzed using systematic tools, such as the Life Cycle Assessment (LCA). In this work, a small-scale aquaponics system (tilapia–lettuce) coupled with a photovoltaic unit was designed and assessed from an environmental perspective using the LCA to quantify its environmental burdens. The photovoltaic unit was sized to supply renewable energy to the system, achieving a reduction of 52% in grid electricity consumption. The environmental impacts of the system were quantified by the LCA, showing that electricity and fish feed were the most important contributors to all the impacts (by 90%), obtaining significant reductions (by 40% on average for all of them) when coupling a photovoltaic unit to the system.