Advancing the Food-Energy–Water Nexus: Closing Nutrient Loops in Arid River Corridors

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• 作者：Jacob G. Mortensen ; Ricardo González-Pinzón ; Clifford N. Dahm ; Jingjing Wang ; Lydia H. Zeglin ; David J. Van Horn
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：August 16, 2016
• 年：2016
• 卷：50
• 期：16
• 页码：8485-8496
• 全文大小：741K
• 年卷期：0
• ISSN：1520-5851

文摘

Closing nutrient loops in terrestrial and aquatic ecosystems is integral to achieve resource security in the food-energy-water (FEW) nexus. We performed multiyear (2005–2008), monthly sampling of instream dissolved inorganic nutrient concentrations (NH₄–N, NO₃–N, soluble reactive phosphorus-SRP) along a ∼ 300-km arid-land river (Rio Grande, NM) and generated nutrient budgets to investigate how the net source/sink behavior of wastewater and irrigated agriculture can be holistically managed to improve water quality and close nutrient loops. Treated wastewater on average contributed over 90% of the instream dissolved inorganic nutrients (101 kg/day NH₄–N, 1097 kg/day NO₃–N, 656 kg/day SRP). During growing seasons, the irrigation network downstream of wastewater outfalls retained on average 37% of NO₃–N and 45% of SRP inputs, with maximum retention exceeding 60% and 80% of NO₃–N and SRP inputs, respectively. Accurate quantification of NH₄–N retention was hindered by low loading and high variability. Nutrient retention in the irrigation network and instream processes together limited downstream export during growing seasons, with total retention of 33–99% of NO₃–N inputs and 45–99% of SRP inputs. From our synoptic analysis, we identify trade-offs associated with wastewater reuse for agriculture within the scope of the FEW nexus and propose strategies for closing nutrient loops in arid-land rivers.