Nanobubble applications in aquaculture industry for improving harvest yield, wastewater treatment, and disease control

Authors: YAPARATNE, SUDHEERA - University Of Maine; MORON-LOPEZ, JESUS - Arizona State University; BOUCHARD, DEBORAH - University Of Maine; GARCIA-SEGURA, SERGI - Arizona State University; APUL, ONUR - University Of Maine

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2024
Publication Date: 4/23/2024
Citation: Yaparatne, S., Moron-Lopez, J., Bouchard, D., Garcia-Segura, S., Apul, O.G. 2024. Nanobubble applications in aquaculture industry for improving harvest yield, wastewater treatment, and disease control. Science of the Total Environment. 931. https://doi.org/10.1016/j.scitotenv.2024.172687.
DOI: https://doi.org/10.1016/j.scitotenv.2024.172687

Interpretive Summary: Aquaculture is controlled farming of aquatic organisms in freshwater or marine water for human consumption. It is gaining increasing attention because it presents a practical opportunity as a sustained source of food that minimizes overfishing impacts in natural sources. The aquaculture industry is one of the fastest-growing industries globally. In 2018, total fisheries and aquaculture production reached an all-time high record of 214 million metric tons, where 87.5 million tons were aquaculture-based. The primary motivation for the advancement of the aquaculture industry is its ability to address global food insecurity and poverty, contribute to livelihood diversification and coastal community resilience, creation of investment opportunities, and reduce pressure on wild capture fisheries to restore coastal and marine habitats. The top ten leading aquaculture animal-producing countries in 2020, shown in Fig. 1, are China (56.7 %), India (9.9 %), Indonesia (6.0 %), Vietnam (5.3 %), Bangladesh (3.0 %), Egypt (1.8 %), Norway (1.7 %), Chile (1.7 %), the United States, Canada (0.7 %), and Nigeria (0.3 %). This aquaculture production of animals mainly includes finfish, crustaceans, and mollusks and does not include algae. The increase in the production of fish, shellfish, and other animals by aquaculture in developing countries compared to the industrialized world can be attributed to the “blue revolution”, which refers to the modern emergence of aquaculture as a major agricultural activity. The commitment of these countries to aquaculture is high, and based on the aquaculture animal production per capita, these producers still have more room for growth in the industry. However, there are still several barriers that prevent its sustainable implementation and further global expansion. These obstacles are due to four main factors: (i) continuous and increasing demand for production; (ii) insufficient biosecurity measures to control waterborne animal diseases; (iii) the exacerbated use of water resources; and (iv) the high environmental impact of effluents.

Technical Abstract: The ever-growing demand for aquaculture has led the industry to seek novel approaches for more sustainable practices. These attempts aim to increase aquaculture yield by increasing energy efficiency and decreasing footprint and chemical demand without compromising animal health. For this, emerging nanobubbles (NBs) aeration technology gained attention. NBs are gas-filled pockets suspended as sphere-like cavities (bulk NBs) or attached to surfaces (surface NBs) with diameters of <1 µm. Compared to macro and microbubbles, NBs have demonstrated unique characteristics such as long residence times in water, higher gas mass transfer efficiency, and hydroxyl radical production. This paper focuses on reviewing NB technology in aquaculture systems by summarizing and discussing uses and implications. Three focus areas were targeted to review the applicability and effects of NBs in aquaculture: (i) NBs aeration to improve the aquaculture harvest yield and subsequent wastewater treatment; (ii) NB application for inactivation of harmful microorganisms; and (iii) NBs for reducing oxidative stress and improving animal health. Thus, this study reviews the research studies published in the last 10 years in which air, oxygen, ozone, and hydrogen NBs were tested to improve gas mass transfer, wastewater treatment, and control of pathogenic microorganisms. The experimental results indicated that air and oxygen NBs yield significantly higher productivity, growth rate, total harvest, survival rate, and less oxygen consumption in fish and shrimp farming. Secondly, the application of air and ozone NBs demonstrated the ability of efficient pollutant degradation. Third, NB application demonstrated effective control of infectious bacteria and viruses, and thus increased fish survival, as well as different gene expression patterns that induce immune responses to infections. Reviewed studies lack robust comparative analyses of the efficacy of macro- and microbubble treatments. Also, potential health and safety implications, as well as economic feasibility through factors such as changes in capital infrastructure, routine maintenance and energy consumption need to be considered and evaluated in parallel to applicability. Therefore, even with a promising future, further studies are needed to confirm the benefits of NB treatment versus conventional aquaculture practices.