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

Abstract

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.