Enhancing Biogas Yield from Tanned Shavings: A Preliminary Study on Pretreatment Strategies

The possibility of anaerobic digestion of leather shavings regardless of tanning agent (chrome, vegetable, synthetic) were was investigated. The fermentation batch test (38 °C) was conducted in 2 L reactors according to modified German norm DIN 38314 S8 and standardized biogas guidance issued by the Association of German Engineers in Dresden, VDI 4630. Chemical pretreatment, using organic compounds for solubilization and organic salts for chrome leaching, was applied. Evaluation encompassed the dynamics of the process, final biogas/methane efficiency, as well as the influence of tanning agent type and pretreatment on fermentation. Results showed varying effects of pretreatment methods on methane production and biogas yields. Depending on the tanning of the agent, biogas yield increased by 37–3002%, 590–3198%, and 403–694%, for chrome, synthetic, and olive-tanned shavings, respectively, compared to the control sample (raw substrate). Findings underscore the need for further mechanistic understanding and optimization of pretreatment methods to maximize biogas production from leather wastes.