Alkaline dehydration can treat human urine to produce a dry and nutrient-rich fertilizer. To evaluate the technology at pilot-scale, we built a prototype with capacity to treat 30 L urine d–1 and field tested it for the first time at a military training camp in Finland. We operated the system for 3 months and monitored the recovery of nutrients, end-product composition, physicochemical properties and energy consumption. Results revealed that the system received less urine than anticipated, but achieved high dehydration rates (30–40 L d–1m–2), recovered 30 ± 6% N, and yielded end-products with 1.4% N, 0.9% P, and 8.3% K. However, we demonstrated that the system had potential to recover nearly 70% N and produce fertilizers containing 13.2% N, 2.3% P, and 6.0% K, if it was operated at the design capacity. The energy demand for dehydrating urine was not optimized, but we suggested several ways of reducing it. We also discussed concerns surrounding non-essential heavy metals, salts, and micropollutants, and how they can be overcome to safely recycle urine. Lastly, we pointed out the research gaps that need to be addressed before the technology can be implemented at larger scale.

中文翻译：

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对源分离人类尿液进行碱性脱水的中试规模系统的现场测试：芬兰的案例研究

碱性脱水可以处理人尿，产生干燥且营养丰富的肥料。为了在中试规模上评估该技术，我们构建了一个能够处理 30 L 尿液 d-1 的原型，并在芬兰的军事训练营进行了首次现场测试。我们将该系统运行了 3 个月，并监测了营养物质的回收率、最终产品成分、理化性质和能源消耗。结果表明，该系统接收的尿液少于预期，但实现了高脱水率（30-40 L d-1m-2），回收了 30 ± 6% N，并产生了含有 1.4% N、0.9% P 和8.3% K。但是，我们证明该系统有潜力回收近 70% 的 N，并生产含有 13.2% N、2.3% P 和 6.0% K 的肥料，如果它以设计容量运行。尿液脱水的能量需求没有得到优化，但我们提出了几种减少它的方法。我们还讨论了围绕非必需重金属、盐和微污染物的问题，以及如何克服它们以安全回收尿液。最后，我们指出了在大规模实施该技术之前需要解决的研究空白。