Abstract Traditional wastewater management uses end-of-pipe approaches to remove pollutants in wastewater before discharge. Although effective in human health protection for decades, this approach of removal and disposal requires a high investment of energy and materials and overlooks the values of the key nutrients in wastewater such as phosphorus (P). Phosphorus in wastewater comes from the human metabolites of food, resulted from crop uptakes of fertilizer that ultimately derived from phosphate rock (PR). PR, however, could be depleted in this century, which would lead to a global food crisis. To address the question whether nutrient recovery is indeed a more efficient strategy from a system perspective and provides more benefits to society, this research compares fertilizer production from struvite to the traditional commercial fertilizers (e.g., diammonium phosphate, DAP). Emergy defined as the available energy required directly and indirectly through all transformations to make a product, process, or service is the tool used for system analysis in this study. Emergy accounting provides system analysis of total resource use and whole system efficiency. The results show that struvite production uses one order of magnitude less emergy than DAP production to produce one unit of fertilizer, indicating that struvite production is a more efficient process. This research sheds light on alternative nutrient management through nutrient recovery, which may achieve economic and environmental benefits and overall higher system efficiency.

中文翻译：

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从城市废水中回收养分以实现可持续粮食生产系统：传统肥料的替代品

摘要 传统的废水管理采用末端处理方法在排放前去除废水中的污染物。虽然几十年来对保护人类健康有效，但这种去除和处置方法需要大量的能源和材料投入，并且忽视了废水中磷（P）等关键营养物质的价值。废水中的磷来自人类对食物的代谢产物，是作物吸收最终来自磷矿 (PR) 的肥料的结果。然而，公关可能会在本世纪耗尽，从而导致全球粮食危机。为了解决从系统角度来看养分回收是否确实是一种更有效的策略并为社会带来更多利益的问题，本研究将鸟粪石的肥料生产与传统的商业肥料（例如磷酸二铵，DAP）进行了比较。能值定义为通过所有转换直接和间接制造产品、过程或服务所需的可用能量，是本研究中用于系统分析的工具。能值核算提供总资源利用和整个系统效率的系统分析。结果表明，鸟粪石生产生产一单位肥料所用的能值比 DAP 生产少一个数量级，这表明鸟粪石生产是一种更高效的工艺。这项研究揭示了通过养分回收进行替代养分管理，这可能会实现经济和环境效益以及整体更高的系统效率。