AMM2FERT- Biochemical Enhancement of Ammonia Fertiliser Production with Sustainable and Low Carbon Principles

项目总体调查结果汇总如下。·农业泥浆和工业肥料中氨、尿素、有机氮和游离氮的浓度根据材料的来源、应用和化学成分的性质而有所不同。猪泥浆与牛泥浆具有不同的成分和特性。猪泥浆主要含有铵态氮，通常为70%和30%的有机氮。而牛泥浆通常含有60%的有机氮和40%的铵态氮。牛泥浆的年龄也对泥浆中可用的氮类型有影响，老化导致有机氮转化为氨态氮。在哈珀亚当斯农场的实验室和示范试验期间分析的样品中的总氮含量范围为650 mg/l至7000 mg/l。然而，一旦在样品试验期间加入固体沉降期，总氮水平稳定在2000至3000 mg/l之间。氨态氮含量随泥浆样品总氮含量的比例变化，范围为氮含量的8%至75%。·对农业氨污染的限制因地区而异，但都变得越来越严格。在英国，氮肥法规通常根据氮的可用性进行区分，具有高水平可用氮的材料，例如家禽粪便、猪泥浆、牛泥浆和肉鸡粪便，在某些情况下受到施用时间限制，并且另外受到规定施用方法的规则的限制。近年来，英国IPPC和硝酸盐脆弱区（NVZ）等法规的实施提高了有机肥料的利用效率;这导致无机氮源（即矿物肥料）的使用减少。在丹麦，也有类似的规定，自1990年以来，氮肥的使用量下降了50%。已执行联合国/欧洲经委会哥德堡议定书和欧盟国家排放上限指令，以在国家一级控制氨排放（以及其他污染物）。《议定书》和《指令》都规定了2010年的国家排放上限，目前两者都在进行修订，以包括修订后的2020年更严格的上限。·实验室和示范试验成功地证明了利用酶处理来提高有机氮转化为氨态氮作为受控挥发和吸收的前体的可行性。浆料基质中的氨态氮含量提高了50%。因此，在工艺的后续阶段提供更高的潜在产量，空气辅助挥发，吸收和中和氨成为液态铵形式。·在早期试验中，DGC物理汽提和氨吸收方法已被证明可将浆料基质中高达85%的氨转化为液态铵溶液。·进一步提高效率和增加产量是可能的。浆料中的高固体和发泡是实验室和演示器试验期间的一个真实的问题，其极大地影响了工艺性能。更好地控制固体含量以及重新设计容器和管道设计以控制泡沫，将改善流体流动并提高对汽提/挥发工艺性能至关重要的通气速率。·在土壤氮指数（SNS）为1的中等土壤上种植的冬小麦作物上，使用（i）添加矿物肥料的乳制品浆料，（ii）单独的矿物肥料，和（iii）从乳制品浆料中回收的硝酸铵作为肥料的相关CO2（eq）排放量见第2节。从AMM 2FERT工艺中回收的硝酸铵的最终排放量为3.26吨CO2（当量）/公顷，低于使用泥浆并添加矿物硝酸铵的标准农业实践产生的排放量，但高于单独使用矿物硝酸铵肥料的排放量。然而，如前所述，与从AMM 2FERT回收的硝酸铵相关的98%的具体排放是由于系统中的电力使用。因此，在这一过程中所使用的能源的少量减少可以大大减少总排放量。进一步的工艺优化工作和可再生能源供应的结合可能会显著减少AMM 2FERT工艺的碳足迹。·AMM 2FERT工艺已经确定了几种新的应用，包括i）将猪和牛的泥浆中的氨直接转化为浓缩的液体铵-N肥料; ii）将容易获得的铵-N厌氧消化后转化为液体铵-N肥料; iii）增强产生尿素酶的微生物的生长，用于营养物的生长和稳定。这些应用为AMM 2 FERT工艺的未来开发提供了真实的市场潜力。

The summary of overall project findings is as follows.• The concentrations of ammonia, urea, organic nitrogen and free available nitrogen in farm slurries and industrial fertilisers vary depending on the nature of the material in terms of its source, application and chemical composition. Pig slurry has different composition and characteristics to Cattle slurry. Pig slurries contain predominantly Ammonium Nitrogen, typically 70% and 30% Organic Nitrogen. Whereas Cattle slurry typically contains 60% Organic Nitrogen and 40% Ammonium Nitrogen. The age of the cattle slurry also has an impact on the nitrogen type available in the slurry with ageing resulting in a conversion of organic nitrogen to ammoniacal nitrogen. Total nitrogen contents in samples analysed during the laboratory and demonstrator trials on Harper Adams farm ranged from 650mg/l and up to 7000mg/l. However, once a solids settlement period was incorporated during sample trials the total nitrogen levels stabilised to within 2000 and 3000mg/l. Ammoniacal nitrogen levels varied as a proportion of the total nitrogen content of the slurry samples ranging from 8% and up to 75% of the nitrogen content.• The restrictions on ammonia pollution in agriculture vary from region to region, but all are becoming more stringent. In the UK nitrogen fertiliser regulations typically discriminates according to nitrogen availability, materials with high levels of available nitrogen such as poultry manure, pig slurry, cattle slurry and broiler manure are in some cases subject to application timing restrictions and additionally to rules which dictate application methods. The imposition of regulations such as IPPC and Nitrate Vulnerable Zones (NVZ) in the UK have in recent years improved the utilisation efficiency of organic fertilisers; this has resulted in the reduced use of inorganic nitrogen sources, i.e. mineral fertilisers. In Denmark where similar regulation was imposed nitrogen fertiliser use has declined by 50% since 1990. The UN/ECE Gothenburg Protocol and the EU National Emissions Ceiling Directive have been implemented to control ammonia emissions (amongst other pollutants) at the national level. Both the Protocol and the Directive have national emission ceilings for 2010, and both are currently undergoing revision to include revised more stringent ceilings for 2020.• Laboratory and demonstrator trials successfully proved the feasibility of utilising enzymatic treatment to enhance the conversion of organic nitrogen to ammoniacal nitrogen as a precursor to controlled volatilisation and absorption. Ammoniacal nitrogen contents within the slurry matrix were improved by up to 50%. Thus offering higher potential yields in subsequent stages of the process the air assisted volatilisation, absorption and neutralisation of ammonia into a liquid ammonium form.• The DGC physical stripping and ammonia absorption method was proven to convert upto 85% of the ammonia in the slurry matrix into a liquid ammonium solution during early trials.• Further efficiency improvements and increased yields may be possible. High solids in the slurry and foaming was a real issue during laboratory and demonstrator trials which impacted greatly on the process performance. Better control of solids content and redesigning vessels and piping design for foaming control would improve fluid flows and increase aeration rates essential to the stripping/volatilisation process performance.• The CO¬2(eq) emissions associated with using (i) dairy slurry topped up with mineral fertiliser, (ii) mineral fertiliser alone, and (iii) ammonium nitrate recovered from dairy slurry as fertiliser on a crop of Winter Wheat grown on a medium soil with a soil nitrogen index (SNS) of 1 are presented in Section 2. The final emissions of the recovered Ammonium Nitrate from the AMM2FERT process are 3.26 tonnes CO2(eq)/ hectare which are lower than the emissions produced by using the standard farming practise of using slurry and topped up with mineral ammonium nitrate, but higher than those of mineral ammonium nitrate fertilisers alone. However, as described previously 98 % of the embodied emissions associated with recovered ammonium nitrate from AMM2FERT are due to the use of electricity in the system. Thus, a small reduction of the energy used in the process could reduce the total emissions dramatically. Further process optimisation work and incorporation of renewable energy supplies can potentially reduce the AMM2FERT process carbon footprint significantly.• Several new applications have been identified for the AMM2FERT process including i) direct conversion of ammonia from pig and cattle slurry to concentrated liquid ammonium-N fertiliser; ii) post-anaerobic digestion conversion of readily available ammonium-N to liquid ammonium-N fertiliser and iii) the enhanced growth of Urease enzyme producing microorganisms for nutrient growth and stabilisation. These applications present real market potential for future exploitation of the AMM2FERT process.