Approach to anaerobic bio-degradation of natural and synthetic fabrics: Physico-chemical study of the alteration processes

In this paper, the mesophilic Biochemical Methane Potential of several fabrics was assessed at different Total Solid concentrations (1-4%TS). Physico-chemical techniques were applied to explore the arising structural changes on fibers during the anaerobic digestion process. Additionally, the modified Gompertz model was used to assess and compare the AD performance of the fabrics. In cellulose-based fibers the production of biogas was enhanced thanks to the easy solubilization of acetate, which is generated upon partial breakage of cellulose bonds. The crystallinity of vegetal fibers decreased significantly from day 19. The highest methane yields were attained for silk and wool fabrics at the lowest TS concentrations. Conformational changes in fibroin and keratin were detected. The highest degrees of degradation were observed in solid samples with lower solid concentrations. Accordingly, the maximum methane yields were reported in the reactors operating with lower TS.