Abstract
As the building sector faces global challenges that affect urban supplies of food, water and energy, multifaceted sustainability solutions need to be re-examined through the lens of built environments. Aquaponics, a strategy that combines recirculating aquaculture with hydroponics to optimize fish and plant production, has been recognized as one of "ten technologies which could change our lives" by merit of its potential to revolutionize how we feed urban populations. To holistically assess the environmental performance of urban aquaponic farms, impacts generated by aquaponic systems must be combined with impacts generated by host envelopes. This paper outlines the opportunities and challenges of using life cycle assessment (LCA) to evaluate and design urban aquaponic farms. The methodology described here is part of a larger study of urban integration of aquaponics conducted by the interdisciplinary research consortium CITYFOOD. First, the challenges of applying LCA in architecture and agriculture are outlined. Next, the urban aquaponic farm is described as a series of unit process flows. Using the ISO 14040:2006 framework for developing an LCA, subsequent LCA phases are described, focusing on scenario-specific challenges and tools. Particular attention is given to points of interaction between growing systems and host buildings that can be optimized to serve both. Using a hybrid LCA framework that incorporates methods from the building sector as well as the agricultural sector, built environment professionals can become key players in interdisciplinary solutions for the food-water-energy nexus and the design of sustainable urban food systems.
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Life cycle assessment of aquaculture systems: Does burden shifting occur with an increase in production intensity?
Life cycle assessment (LCA), a tool used to assess the environmental impacts of products and processes, has been used to evaluate a range of aquaculture systems. Eighteen LCA studies were reviewed which included assess- ments of recirculating aquaculture systems (RAS), flow-through systems, net cages, and pond systems. This re- view considered the potential to mitigate environmental burdens with a movement from extensive to intensive aquaculture systems. Due to the diversity in study results, specific processes (feed, energy, and infrastructure) and specific impact categories (land use, water use, and eutrophication potential) were analyzed in-depth. The comparative analysis indicated there was a possible shift from local to global impacts with a progression from extensive to intensive systems, if mitigation strategies were not performed. The shift was partially due to increased electricity requirements but also varied with electricity source. The impacts from infrastructure were less than 13 % of the environmental impact and considered negligible. For feed, the environmental impacts were typically more dependent on feed conversion ratio (FCR) than the type of system. Feed also contributed to over 50 % of the impacts on land use, second only to energy carriers. The analysis of water use indicated intensive recirculating systems efficiently reduce water use as compared to extensive systems; however, at present, studies have only considered direct water use and future work is required that incorporates indirect and consumptive water use. Alternative aquaculture systems that can improve the total nutrient uptake and production yield per material and energy based input, thereby reducing the overall emissions per unit of feed, should be further investigated to optimize the overall of aquaculture systems, considering both global and local environmental impacts. While LCA can be a valuable tool to evaluate trade-offs in system designs, the results are often location and species specific. Therefore, it is critical to consider both of these criteria in conjunction with LCA results when developing aquaculture systems.
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- Award ID(s):
- 1942110
- NSF-PAR ID:
- 10206989
- Date Published:
- Journal Name:
- Aquacultural engineering
- Volume:
- 92
- ISSN:
- 1873-5614
- Page Range / eLocation ID:
- 102130
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.aquaeng.2020.102130
