Valorization of anaerobic digestate: innovative approaches for sustainable resource management and energy production - case studies from Turkey and Poland

While renewable energy sources are getting high interest, amounts of biogas plants have visible increases. In addition to energy, these facilities also produce a nutrient-rich organic material called digestate, which can be utilized as a crop fertilizer. Scientific research on digestate usage has increased with the new environmental protection laws for direct discharges, particularly after the 2000s. The nutrient composition of digestate provides a variable range of applications, rendering it a valuable commodity. In this study, the energy production capacity of Turkey and Poland from biogas power plants are compared, and the case study was used to estimate the amount of digestate produced for both countries. Two recovery technologies, such as organomineral fertilizer production and an innovative technology of super-heated steam torrefaction to produce valuable products and energy from digestate, were presented with their energy potentials. The outcomes of the case study indicate that harnessing digestate as an energy source holds the capability to make a 3.64% to 4.26% contribution to the overall energy consumption of Turkey and Poland through torrefied biochar energy. As per the results derived from the fertilizer case study, the application of digested biomass as a source of organomineral fertilizer holds the capacity to yield approximately 16,142,806 tons and 9,648,142 tons of fertilizer for Turkey and Poland, correspondingly.