NTPlus - developing the circular economy in agriculture

该项目展示了从水中回收营养物质，减少了农业对Haber过程中氮肥和Mannheim过程中硫酸盐肥的依赖，帮助农业实现净零排放。这有可能彻底改变硝酸盐的去除，这是在硝酸盐水平高于安全水平的地方进行的。地下水的硝酸盐污染发生在集约化农业地区，处理时使用大量的盐，产生盐水硝酸盐废物流，通常必须将其运往大型废水处理厂。盐可以再生用于去除硝酸盐的离子交换树脂，但该过程的效率通常为~10%。这是一个昂贵的过程：在英国，水行业的结构使工厂的资本和运营成本能够分散在一个庞大的客户群上，但是，在世界其他地区，水行业是分散的，禁止更广泛地使用硝酸盐去除。例如，在加利福尼亚的中央山谷，超过200个小型社区供水系统在十多年来一直超过硝酸盐的最高水平，而没有安装一个处理系统。大多数硝酸盐处理场都有邻近的农田，而且农民在非季节施用钾肥氯化钾，这样在种植作物之前，氯化物就被冲走了。该项目将以接近100%的效率展示离子交换树脂的再生，生产含有钾、硫酸盐、硝酸盐、钙和镁的低氯化物肥料产品，以及天然黄腐酸（被离子交换系统清除），这些产品改善了土壤条件，并参与了土壤中微量矿物质的运输。这些可以被附近的农场用于智能（可变速率施肥）灌溉，并且可以成为现有肥料制造商的新产品，使他们能够运输固体补充添加剂并弥补农场的液体产品。在英国，通过鼓励采用智能灌溉，农作物产量将定期提高10%，同时更有效地利用肥料和水。在英国，灌溉的使用正在增加，以确保提高对气候变化的适应能力，特别是在使用灌溉储水的地方，促进冬季抽水，并有可能利用这些设施减轻洪水。在Vadose层中已经存在的硝酸盐数量很大（英国地质调查局估计600 - 1800米深），被视为水源的“定时炸弹”。这个项目把这个问题变成了一个可持续的解决方案。生产的产品比原材料投入的价值更大，这使得指数增长的潜力成为可能。全球每年有9000万吨钾肥用于农业。如果将其中的10%用于从水中回收营养物质，这将使土壤和淡水系统的氯化物输入减少20多立方米，二氧化碳排放量减少30多立方米，其中近1000立方米的二氧化碳被额外的作物生产捕获。

This project demonstrates the recovery of nutrients from water, decreasing agriculture's dependence on the Haber process for nitrogen fertilisers and the Mannheim process for sulphate fertilisers, helping agriculture move towards net zero. This has the potential to revolutionise nitrate removal, which is carried out where nitrate levels are above safe levels. Nitrate pollution of ground water occurs in regions of intensive agriculture and treatment uses large quantities of salt, producing a brine nitrate waste stream which often has to be tankered to a large waste water treatment works. The salt regenerates the ion exchange resin used to remove nitrate, but the process is typically ~10% efficient. This is an expensive process: in the UK, the structure of the water industry enables the capital and operational costs of plants to be spread over a large customer base, but, in other parts of the world, the water industry is fragmented, prohibiting the wider use of nitrate removal. For example, in the Central Valley in California, over 200 small community water systems have consistently exceeded the maximum nitrate level for over a decade, without a single treatment system being installed.Most nitrate treatment sites have adjacent farmland - and the farmer applies potash fertiliser, potassium chloride, out of season so the chloride is washed away before the crops are planted. This project will demonstrate regeneration of the ion exchange resin at close to 100% efficiency, producing low-chloride fertigation products containing potassium, sulphate, nitrate, calcium and magnesium, as well as natural fulvic acids (scavenged by the ion exchange system) which improve soil condition and are involved in the transportation of trace minerals in soils. These could be used by a nearby farm in smart (variable rate fertilisation) irrigation, and could become a new product for existing fertiliser manufacturers, enabling them to ship solid complementary additions and make up the liquid products on the farm.By encouraging the uptake of smart irrigation in the UK, crop yield gains of 10% would be regularly achieved, along with more efficient use of both fertilisers and water. Irrigation use is increasing in the UK to ensure increased resilience to climate change, particularly where irrigation water storage is used, facilitating winter abstraction and the potential to use such facilities for flood mitigation. The amount of nitrate already present in the Vadose layer is substantial (BGS estimate 600 - 1,800M te) and is seen as a 'timebomb' for water sources.This project turns this problem into a sustainable solution. The products produced have a greater value than the raw material inputs, which enables the potential for exponential growth. Globally, 90 M te of potash is used annually in agriculture. If 10% of this were used to recover nutrients from water, this would reduce chloride inputs to soil and fresh water systems by over 20 M te and reduce CO2 emissions by over 30 M te, with nearly 1,000 M te of CO2 captured in additional crop production.