To get an idea of what types of nutrient sources or wastes are being used most in patents from the CAS Content Collection that were published over the last two decades the sums of patents for several broad categories were examined (Figure ). Patents were focused on the use of agricultural and food wastes and manure, followed by sludges, wastewater, and ashes, then biomass, algae, and urine sources. These waste sources have useful organic matter, biomass and nutrients that can be recovered or repurposed for agricultural or other uses with proper processing techniques. Examining patenting trends on products derived from said broad categories of wastes demonstrates a strong focus on phosphate recovery involving manure or wastewaters, while plant-based agricultural wastes and food processing wastes were more often but not entirely associated with composts, soil amendments, as feedstock for biochar and biofuels, or used multicomponent fertilizers. Returning to the idea of a circular economic approach, chemical fertilizer nutrients can be derived from wastes, which are represented broadly by phosphates, nitrates, nutrients, trace elements, and superphosphates in this chart (Fig. ). However, patent literature on deriving agricultural uses from wastes over the last two decades has been dominated by production of soil amendments. This is followed by biogas which can be used to generate energy for the process or for other purposes. Biochar, often derived from biomass feedstocks such as algae, is also discussed in patents. Biomass, whether grown for the purpose or as a process waste byproduct can contribute to the circular bioeconomy through its use in biochar, soil amendments, compost, biofuels, and as absorbents of nutrients. As the data illustrates, phosphates, nitrates and trace elements were associated with waste and wastewater recycling and sustainable fertilizers. As an accounting of the forms of nitrogen, phosphorus, and potassium that we found associated with the sustainable fertilizer publications in our dataset we provide Table , wherein elemental nutrients are most likely to have been measured in soils, plant or fertilizer products and salt and mineral forms are either manufactured fertilizer chemical forms or derived from wastes or wastewaters. Ammonium, nitrate, potassium, and phosphorus salts, phosphoric acid, and minerals are found. Struvite, a nutrient often generated from precipitation from wastes and wastewaters, is discussed in more detail later in this report.