Extra CO2 sequestration following reutilization of biomass ash

• Published in: The Science of the total environment Vol. 625; pp. 1013 - 1020
• Main Authors: López, Rafael, Díaz, M. Jesús, González-Pérez, José A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2018
• Subjects: biomass; Black carbon; calcareous soils; carbon; carbon dioxide; carbon sequestration; combustion; Fertilizer; gasification; Olive cake; Potassium; potassium fertilizers; power plants; Soil carbonates; BBA; BECCS; Olive cake; FBA; TSC; DTG; Soil carbonates; Potassium; Black carbon; BA; TGA; Fertilizer
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.12.263

Although combustion ashes are usually used in soils, little attention is paid to the CO2 sequestration potential of this practice. The present study aims to quantify carbon sequestration as carbonate compounds in a tailored synthetic calcareous soil treated with biomass ash from a gasification power plant that uses olive cake. It is estimated that after ash amendment, 14.5g CO2 remained fixed per kg of fly biomass ash, 16.5g CO2 per kg of bottom biomass ash with plant cultivation and 19.7g CO2 per kg of bottom biomass ash without plant cultivation. This inorganic C fixation plus the organic (black) C contained in the ashes made the reutilization of ashes as K fertilizer a relevant practice due to its C resilience and rate, with a yearly C sequestering potential of ca. 8% of ‘Soil carbon 4 per mille’ goal, an initiative launched at the COP21. •Olive cake ashes capture CO2 after biomass combustion.•Biomass combustion ashes can be reused as fertilizer.•CO2 remains fixed after biomass ashes are added to a calcareous soil.•Additional C is fixed as black C is already in ashes.•The C sequestering potential of biomass ashes is significant. [Display omitted]