Biodegradation of nonlignocellulosic substances II: physical and chemical properties of sawdust before and after use as artificial soil

The physical properties of sawdust including porosity, water retention, and water drainage were analyzed to prove its suitability for use as an artifi cial soil in the automatic decomposer-extinguisher (GADE) machine. The phys ical and chemical properties of residual sawdust from the GADE machine were also analyzed, the mechanical abrasion of sawdust in the GADE machine was tested, and the morphology of this residue was observed through a scanning electron microscope to investigate changes of these properties in the mediu m of decomposing garbage. Sawdust, which showed a lower specific gravity an d larger porosity than soil, is considered capable of supplying air to bact eria. Tt was found that sawdust became worn from the operation of the machi ne. The spaces of residual sawdust were still observed, but water drainage decreased. The portion of hollocellulose in residual sawdust decreased, alt hough the extractives in it increased, Results indicated that the capacity of sawdust to function as an artificial soil in the GADE machine was decrea sed owing not only to the destruction of sawdust grain but also to the adhe rence of products from decomposition, such that sawdust needed to be replac ed every few months.