Self-Sustaining Double Stage Circularity Through Utilization of Sunflower Agriculture’s Waste into Bio-Fertilizers: Commissioning of Full-Scale Facility

The conception of circular economy is one of the crucial approaches that could accelerate the processes of achieving the sustainable development goals that challenged all industries and societies. This study aims to develop a full-scale technology for self-sustaining double stage circularity through utilization of sunflower agriculture’s waste into bio-fertilizers. The investigation is performed in Bulgaria as available sunflower hush ashes (SHA) are subjected to analyses regarding their applicability for bio-fertilizer production. The design of technology and full-scale equipment commissioning process are described. The conditions and results from adjustment tests are presented and based on them the optimal operating parameters are defined. The successful granulation of different samples of SHA at these conditions is performed as the final granular bio-fertilizers are characterized with content of 30 wt. % K2O and 5 % wt. P2O. The moisture of prepared granules is approx.. 5 wt. % and they pass the crushing tests at 2.5 kgf. The bio-toxicity of bio-fertilizer is also analyzed and the results show their applicability in agriculture. The proposed approach allows the initial sources of K2O and P2O from soil feeding the sunflowers to circulate in different industrial technologies and to enter again in the soil through bio-fertilizers.