Recovering resources from wastewater systems is increasingly being emphasised. Many technologies exist or are under development for recycling nutrients such as nitrogen and phosphorus from wastewater to agriculture. Planning and design methodologies are needed to identify and deploy the most sustainable solutions in given contexts. For the environmental sustainability dimension, life cycle assessment (LCA) can be used to assess environmental impact potentials of wastewater-based nutrient recycling alternatives, especially nitrogen and phosphorus recycling. This review aims to evaluate how well the LCA methodology has been adapted and applied for assessing opportunities of wastewater-based nutrient recycling in the form of monomineral, multimineral, nutrient solution and organic solid. We reviewed 65 LCA studies that considered nutrient recycling from wastewater for agricultural land application. We synthesised some of their insights and methodological practices, and discussed the future outlook of using LCA for wastewater-based nutrient recycling. In general, more studies suggested positive environmental outcomes from wastewater-based nutrient recycling, especially when chemical inputs are minimised, and source separation of human excreta is achieved. The review shows the need to improve methodological consistency (e.g., multifunctionality, fertiliser offset accounting, contaminant accounting), ensure transparency of inventory and methods, consider uncertainty in comparative LCA context, integrate up-to-date cross-disciplinary knowledge (e.g., agriculture science, soil science) into LCA models, and consider the localised impacts of recycled nutrient products. Many opportunities exist for applying LCA at various scales to support decisions on wastewater-based nutrient recycling - for instance, performing "product perspective" LCA on recycled nutrient products, integrating "process perspective" LCA with other systems approaches for selecting and optimising individual recovery processes, assessing emerging nutrient recovery technologies and integrated resource recovery systems, and conducting systems analysis at city, national and global level.

中文翻译：

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从废水中回收营养物的生命周期评估：一项重要的审查。

从废水系统中回收资源越来越受到重视。已经存在或正在开发许多技术，用于将营养物（例如氮和磷）从废水中回收利用到农业中。需要规划和设计方法论，以在给定环境下识别和部署最可持续的解决方案。对于环境可持续性方面，可以使用生命周期评估（LCA）来评估基于废水的养分循环利用替代品，尤其是氮和磷的循环利用对环境的潜在影响。这篇综述旨在评估LCA方法的适应性和适用性如何，以单矿物，多矿物，营养液和有机固体的形式评估基于废水的营养物再循环的机会。我们回顾了65个LCA研究，这些研究考虑了从农业土地应用中的废水中回收养分。我们综合了他们的一些见解和方法论实践，并讨论了使用LCA进行废水养分循环利用的未来前景。总的来说，更多的研究表明，基于废水的养分循环利用会对环境产生积极的影响，尤其是当化学物质的投入减少到最低程度并实现人类排泄物的来源分离时。审查表明，需要提高方法的一致性（例如，多功能性，肥料补偿核算，污染物核算），确保清单和方法的透明度，在比较的LCA环境中考虑不确定性，整合最新的跨学科知识（例如农业）科学，土壤科学）纳入LCA模型，并考虑回收营养产品的局部影响。存在各种机会来应用各种规模的LCA来支持基于废水的养分循环利用的决策-例如，对回收的养分产品执行“产品透视图” LCA，将“过程透视图” LCA与其他系统方法集成在一起以选择和优化单个回收过程，评估新兴的营养物回收技术和综合资源回收系统，并在城市，国家和全球范围内进行系统分析。