Advancing Circular Agriculture through Nutrient Upcycling: Digestate as the Basis for Enhanced Efficiency Fertilizers

Alternative disposal pathways for anaerobic digestion (AD) waste byproducts (digestate) are needed to utilize this resource reduce greenhouse gas emissions and avoid nutrient loss caused by inefficient land application providing an opportunity to use the digestate as the basis of an enhanced efficiency fertilizer (EEF). However raw digestate does not meet most agricultural requirements and falls short of being an EEF. With this SBIR project GreenTechnologies LLC (GT) will adapt patented technologies to produce organic enhanced efficiency fertilizers using the digestate as a feedstock. The application responds to research topic 8.4 Conservation of Natural Resources with emphasis on soil health and nutrient management. The SBIR effort will culminate in the commercialization of a new category of enhanced- efficiency recycled-nutrient fertilizers based on digestate. Phase I efforts will evaluate the technical feasibility of adapting GT's technologies to digestate to produce commercial fertilizers. Phase I objectives are: 1) evaluate the nutrient content and physical characteristics of different digestate sources; 2) determine target nutrient levels and adapt GT's patented enhancement processes to produce dried digestate-based fertilizers; and 3) characterize the new products and quantify nutrient release profiles. Anticipated results are a new source of domestically produced EEFs and a generalized process that will be portable to other facilities or producers tailorable to meet regional nutrient needs. Initial strategies for commercialization take advantage of GT's position in the organic fertilizer marketplace. Longer term commercialization will use the technology as the basis for strategic partnerships to broaden its practice.