Biodegradation stability of organic solid waste characterized by physico-chemical parameters

Abstract

A generalized methodology to characterize the bio-chemical properties of waste results is of great interest in waste management. The chemical and physical methods traditionally used to determine the organic content of solids, such as volatile solids content (VS), total organic carbon content (TOC), cellulose (CEL), hemicellulose (HEM), lignin (LIG), and leaching tests with later analyses of the eluate are easy to perform and to reproduce, but they do not give enough information about the rate of waste stabilization. On account of this, more specific assays like Biochemical Methane Potential (BMP) or respirometry assays are nowadays being performed. These biodegradation assays are more complex because they require extensive time and specific equipments and a number of influencing parameters have to be considered. These difficulties promoted the interest in looking for correlations between “conventional”, simpler analyses and biodegradation assays. Based on characterization results obtained by different authors in old waste, ratios between BMP and several parameters are studied in this paper, showing significant correlations in most cases. As a theoretical analysis indicates, only for CEL and CEL+HEM laws that can be generalized to other cases were obtained. VS and (CEL+HEM)/LIG are indicators of the degradation state too, but only with regard to samples of the same type of waste. Since VS content does not inform about organic matter biodegradability and (CEL+HEM)/LIG is independent of the inorganic fraction of waste, the laws BMP/VS and BMP/[(CEL+HEM)/LIG] obtained are different for each studied data series.