Abstract. Soil degradation is a global challenge that is intrinsically linked to climate change and food security. Soil degradation has many causes, but all degraded soils suffer from poor soil structure. The UN’s Sustainable Development Goals 12, 13 and 15 strive towards responsible consumption and production, building a zero-waste circular economy, achieving net zero by 2030 and reversing land degradation to protect one of our most valuable assets, soil. Global efforts to stop and even reverse soil degradation require sources of both organic and inorganic materials to rebuild soil structure. The increasing global production of water treatment residual (WTR), an organo-mineral waste product from clean water treatment, means that the sustainable reuse of this waste provides a potential timely opportunity. Recycling or reuse of WTR to land is commonplace across the world but is subject to limitations based on the chemical properties of the material. Very little work has focused on the physical impacts of Fe-WTR application and its potential to rebuild soil structure particularly improving its ability to hold water and resist the effects of flooding. This paper presents novel research in which the use of Fe-WTR and Fe-WTR/compost [1:1] co-amendment has shown to be beneficial for a soil’s water retention, permeability, volume change, and strength properties. Application rates of WTR were 10 and 30 % by dry mass. Compared to the control soil, co-amended samples have 5.7 times the hydraulic conductivity (570 % improvement), 54 % higher shear strength and 25 % greater saturated water content. Single WTR amendment had 26 times the saturated hydraulic conductivity (2600 % improvement), 129 % higher shear strength and 13.7 % greater saturated water content. Data indicates that WTR can be added as a single amendment to significantly improve soil physical characteristics where shear strength and hydraulic conductivity are the most important factors in application. Although the co-application of Fe-WTR with compost provides a lesser improvement in shear strength and hydraulic conductivity compared to single WTR amendment, the co-amendment has the best water retention properties and provides supplementary organic content, which is beneficial for environmental applications where the soil health (i.e. ability to sustain ecosystem functions and support plants) is critical. We develop the term ‘flood holding capacity’ to holistically describe the physical ecosystem services that soil delivers, which incorporates not only the gravimetric water content but the extra water storage potential due to increases in volume that occur in organic rich soils, the transmissivity of the soil (hydraulic conductivity) and the shear strength of a soil, which determines how well a soil will resist the erosive forces of water movement.

中文翻译：

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再利用铁水处理残留物作为土壤改良剂，以改善物理功能和抗洪能力

摘要。土壤退化是一项全球性挑战，与气候变化和粮食安全有着内在的联系。土壤退化的原因有很多，但所有退化的土壤都受到土壤结构不良的影响。联合国可持续发展目标 12、13 和 15 努力实现负责任的消费和生产，建设零废物循环经济，到 2030 年实现净零排放并扭转土地退化，以保护我们最宝贵的资产之一——土壤。阻止甚至逆转土壤退化的全球努力需要有机和无机材料的来源来重建土壤结构。水处理残留物 (WTR) 是一种来自清洁水处理的有机矿物废物，其全球产量不断增加，这意味着这种废物的可持续再利用提供了潜在的及时机会。WTR 回收或再利用到土地上在世界各地都很常见，但会受到基于材料化学性质的限制。很少有工作关注 Fe-WTR 应用的物理影响及其重建土壤结构的潜力，特别是提高其保水和抵抗洪水影响的能力。本文提出了新的研究，其中使用 Fe-WTR 和 Fe-WTR/堆肥 [1:1] 共同修正剂已证明对土壤的保水、渗透性、体积变化和强度特性有益。WTR 的施用率为干重的 10% 和 30%。与对照土壤相比，共同修正的样品的水力传导率提高了 5.7 倍（提高了 570%），剪切强度提高了 54%，饱和含水量提高了 25%。单一 WTR 修正剂的饱和导水率提高了 26 倍（提高了 2600%），剪切强度提高了 129%，饱和含水量提高了 13.7%。数据表明，WTR 可以作为单一改良剂添加，以显着改善土壤物理特性，其中剪切强度和水力传导率是应用中最重要的因素。尽管与单一 WTR 改良剂相比，Fe-WTR 与堆肥的共同应用在剪切强度和水力传导率方面的改进较小，但共同改良剂具有最佳的保水性能并提供补充有机含量，这有利于环境应用土壤健康（即维持生态系统功能和支持植物的能力）至关重要。