Energy Demand of Nitrogen and Phosphorus Based Fertilizers and Approaches to Circularity

The climate-related concerns associated with the manufacturing of synthetic fertilizers are largely traced back to energy and carbon emissions during the chemical manufacturing of ammonia. However, synthetic fertilizers are made up of several macronutrients (nitrogen, phosphorus and potassium), each with different energy intensities and environmental impacts. With the movement toward resource circularity, there is a need to create a more holistic view regarding the process energy associated with synthetic inorganic fertilizers, including nitrogen and phosphorus. Here, we first describe the growing production and consumption of inorganic (synthetic) and organic (animal waste) nutrients in agriculture as well as the process energy associated with the production of granular phosphorus and nitrogen-based fertilizers. Next, we present projected global demand of nitrogen and phosphorus nutrients based on various sustainability and societal equity scenarios to make an argument for nutrient recovery as a viable approach to meet this demand. Finally, we discuss the characteristics and challenges of emerging technologies for nutrient recovery along with baseline performance and costs of current operational recovery facilities.

与合成肥料生产相关的气候问题在很大程度上可追溯到氨化学制造过程中的能源消耗和碳排放。然而，合成肥料由几种大量营养素（氮、磷和钾）组成，每种营养素在能源强度和环境影响方面都有所不同。随着资源循环利用的发展，有必要对与合成无机肥料（包括氮和磷）相关的生产过程能源有一个更全面的认识。在此，我们首先描述了农业中无机（合成）和有机（动物粪便）养分的生产和消费增长情况，以及与颗粒状磷和氮基肥料生产相关的生产过程能源。接下来，我们根据各种可持续性和社会公平情景，对氮和磷养分的全球需求进行了预测，以论证养分回收是满足这一需求的可行方法。最后，我们讨论了新兴养分回收技术的特点和挑战，以及当前运营回收设施的基本性能和成本。