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Sustainable food production with aquaponics

thesis
posted on 01.08.2022, 13:28 authored by Peng ChenPeng Chen

Sustainable food production is about producing more and better with less.As an emerging CEA system, aquaponics integrates recirculating aquaculture systems and hydroponics and can achieve the three SDGs mentioned above. However, challenges in sustainable aquaponics commercialization remains and my thesis addresses the following three layers of sustainable aquaponics  development:  sustainability  assessment,  sustainable  system  design  and management, understanding biological mechanisms for scalability.

I conducted acradle-to-gate life cycle assessment (LCA)and compared the environmental performance, on an economic basis, of aquaponics andhydroponics withidentical system design in Indiana, US. Aquaponics produced 45% lower endpoint environmental impact than hydroponics.Electricity use for greenhouse heating and lighting, and water pumping and heating contributed to themajority of the environmental impacts of both systems, which was followed by the production of fishfeed and fertilizers. However, changing the energy source from coal to wind power could make thehydroponic system more environment-friendly than the aquaponic system. This LCA study can provideCEA farmers with the groundwork to reduce the environmental cost of their production.

Aquaponics uses bacterial processes and plant nutrient uptake to recover nutrient from aquaculture wastewater. However, little is known which wastewater management strategy, autotrophic or heterotrophic, is best suited for the four objectives: nutrient recovery, system reliability, and growth and physiological welfare of fish and plants. In this study, I found that pH6 had the highest nitrogen (N) use efficiency (NUE) (assimilated by fish and plants, 65.5%) and the lowest N loss as gas (34.5%), followed by pH6M (55.5% and 44.5%,respectively), suggesting that lower pH and less organic carbon in aquaponics could enhance NUE and reduce N loss. pH6M had the highest phosphorus (P) use efficiency (PUE) (assimilated by fish and plants, 65.0%) suggesting that lower pH and organic carbonaddition could facilitate P recovery from wastewater. 

Reverse osmosis (RO) water enables aquaculture to expand in places where natural water is not desirable and reduces uncertainty in the operation. However, high K+environment of RO in  aquaponics  couldinduce  physiological  stress,  but  adaptation  mechanism  is  unknown. Proteomic analysis revealed up-regulation of stress response proteins and down-regulation of V-type H+-ATPase and other ion transporters, suggesting cellular adaptation of fish to RO water stress. In conclusion, fish was able to accommodate to the RO environment and the benefits of efficient ammonia excretion and increased feed consumption outweighed the stress caused by RO. RO water could be a standardized water source for better animal welfare, reduce uncertainty in production and assist scaling up aquaponics industry.

Funding

Purdue University Department of Forestry and Natural Resources

History

Degree Type

Doctor of Philosophy

Department

Forestry and Natural Resources

Campus location

West Lafayette

Advisor/Supervisor/Committee Chair

Paul Brown

Additional Committee Member 2

Hye-Ji Kim

Additional Committee Member 3

Zhi Zhou

Additional Committee Member 4

Jen-Yi Huang

Additional Committee Member 5

Kwamena Quagrainie