Applications of gravity aeration system in aquaculture—a systematic review

The exponentially growing population, rapid mechanization, urbanization, and modern agricultural operations diminish water resources, resulting in water scarcity. In a non-technologically feasible manner, worldwide aquaculture development is also becoming a matter of concern, responsible for water pollution. Aeration is one of the alternative methods, which help to improve dissolved oxygen (DO) in water body. Dissolved oxygen (DO) can be enhanced by both natural and artificial means, whereas artificial aeration practice is more efficient and effective. While considering the various artificial aeration systems, gravity aeration is one of the most effective and low energy cost aeration practices. Gravity aerators expand the air–water mass exchange by creating air bubbles, expanding the surface area, and fulfilling the water body’s DO. Assessment of various operating parameters (geometric and dynamic) related to gravity aeration is necessary to improve the oxygen transfer performance. However, gravity aerators have started becoming popular among the researchers and the fish aquaculturists. The main objective of this study is to present a comprehensive review of gravity aeration systems. This paper is to present a brief overview of the aeration principle and various gravity aerators that are of importance to aquaculture. In addition, the economic feasibility of gravity aeration systems over other existing aeration practices is compared.