The sustainable production of fertilizers, especially those based on phosphorus, will be one of the challenges of this century. Organic wastes produced by the agriculture, urban and industrial sectors are rich in nutrients which can be conveniently recovered and used as fertilizers. In this study five full scale systems for the recovery of nutrients from anaerobic digestate produced in farm-scale plants were studied. Monitored technologies were: drying with acidic recovery, stripping with acidic recovery and membrane separation. Results showed good performances in terms of nutrients recovery with average yields always over 50% for both nitrogen and phosphorus. The techno-economic assessment showed how the specificity of the monitored systems played a major role: in particular, membranes were able to produce a stream of virtually pure water (up to 50% of the treated digestate) reducing the digestate volume, while drying, because of the limitation on recoverable heat, could treat only a limited portion (lower than 50%) of produced digestate while stripping suffered some problems because of the presence of suspended solids in the liquid fraction treated. Specific capital and operational costs for the three systems were comparable ranging between 5.40 and 6.97 € per m³ of digestate treated and followed the order stripping > drying > membranes. Costs determined in this study were similar to those observed in other European experiences reported in literature.

肥料的可持续生产，特别是基于磷的肥料，将是本世纪的挑战之一。农业，城市和工业部门产生的有机废物富含营养，可以方便地回收并用作肥料。在这项研究中，研究了五种用于从农场规模植物中产生的厌氧消化物中回收营养的全规模系统。监测的技术为：酸性回收干燥，酸性回收汽提和膜分离。结果表明，在养分回收方面表现良好，氮和磷的平均产量始终超过50％。技术经济评估表明，受监控系统的特异性如何发挥主要作用：特别是，膜能够产生几乎纯净的水流（至多为处理过的消化液的50％），减少了消化液的体积，而干燥时，由于可回收热量的限制，只能处理一部分（低于50％）的水。汽提过程中产生的消化物遇到了一些问题，因为处理的液体馏分中存在悬浮固体。这三个系统的特定资本和运营成本相当，在每平方米5.40欧元和6.97欧元之间处理³消化物，然后依次进行汽提>干燥>膜。这项研究确定的成本与文献报道的其他欧洲经验中观察到的成本相似。