Life Cycle Assessment of a Commercial-Scale Freshwater Aquaponic System

摘要

Life cycle assessment was used to evaluate environmental impacts of simultaneous fish and plant production through the aquaculture practice of aquaponics. In aquaponics, hydroponic plant production replaces the conventional water treatment processes of microbial nitrification and water exchanges required in recirculating aquaculture systems (RAS) to maintain water quality. The system expansion method was used to assess potential avoided burdens from coproduction of recovered solids, plant production, and water treatment. Results indicated that electricity and feed were the main contributing factors to environmental impact. Impact assessment results were highly sensitive to changes in electricity inputs, suggesting that a small reduction in electricity could contribute to a correspondingly large change in the environmental impact. Avoided burdens associated with coproducts contributed to a moderate reduction in environmental impact compared to reducing total electricity inputs or sourcing electricity from renewable sources. Of the coproducts considered, avoided water treatment contributed greatest to reductions in environmental impact due to reductions in energy use, water use, and eutrophication potential. The large reduction in water use suggests that plant production can contribute to increased recirculation rates and further reduce water inputs associated with aquaculture. Aquaponics, similar to other RASs, essentially eliminates local ecological impacts at the cost of high energy use and the addition of industrial fish feeds. Development of sustainable land-based aquaculture will encompass many production systems, including aquaponics; however, all systems will benefit from improved energy efficiency, increased accessibility to renewable energy sources, and development of sustainable fish feeds.