Process Sustainability Analysis of Biorefineries to Produce Biofertilizers and Bioenergy from Biodegradable Residues

The use of chemical fertilizers is essential for agricultural development when soils do not have the nutritional balance required for plants. The continuous use of chemical fertilizers has changed the soil physicochemical and biological properties. Biofertilizer production has been considered as an alternative to reduce chemical fertilizers dependence and the environmental impact. The aim of this study is the evaluation of three technologies for the production of biofertilizers and bioenergy at technical, economic, environmental, and social levels. Ammonium sulfate and digestate-based biofertilizers were obtained via anaerobic digestion; biochar was produced via gasification; and amino acids as plants biostimulants were obtained via protein hydrolysis. Different indicators were calculated for elucidating the sustainability of the processes. Technical, economic, environmental, and social analysis is performed for each of the biorefineries processing stage (complex and stand-alone) without considering the agronomic stage or other value chain links. Scenario 1 presented a positive impact on the economic, environmental, and social aspects since this process has a payback period of 10 years, a carbon footprint of 0.67 kg CO2-eq/kg product, and a potential to generate nine jobs in the Colombian context due to the products portfolio, in contrast with scenario 2 and 3. As conclusion, the integration of biofertilizers and bioenergy in biorefineries have the potential to expand the range of bioproducts and to increase the process sustainability.