Manufacturing of a Granular Fertilizer Based on Organic Slurry and Hardening Agent

Abstract

The manufacturing of a granular fertilizer based on organic slurry (OS) and sorptive materials aims to enhance the circular economy. This article describes a technology that was conceived after appraising the chemistry of the anaerobic digestate and wood ash and the synergies of combining both materials. The information available in the literature about similar materials such as cattle slurry and lime was also considered to build a better understanding of the underlying science. The processes and machinery designed were optimized from the points of view of energy and material consumption, cost of storage, transportation and land application. The system was sized to process 1 tonne of OS (97% moisture) in a 10 h batch-shift, consuming 140 kg of wood pellets and 0.55 kW of electricity for the fan blowing preheated air. The results of the market research allowed us to reach the most economically viable routes for the commercialization of granular fertilizers. Based on the financial study, an initial investment of GBP 20,000 is needed to successfully implement the value proposition and business plan. The wide adoption of the composite fertilizer improves the management of the OS and reduces the contamination of air, soil, and water derived from intensive agricultural practices.