Statistical Analysis to Correlate Bio-physical and Chemical Characteristics of Organic Wastes and Digestates to Their Anaerobic Biodegradability

Solid waste biodegradability is a key parameter to control and optimize high solid anaerobic digestion (HSAD) of biowaste (BW) and residual municipal solid waste (RMSW). It enables to assess the biomethane potential and the biostability achieved by the process. The objective of this study was to correlate the biochemical methane potential (BMP) with selected analytical parameters commonly used to predict bioreactivity of solid organic samples, such as global analyses (VS, TOC, CODTot N-TKN), biochemical analyses (humic substance index, Van Soest fractionation method, total lipid content, and total protein content), leaching behaviour (VFA, CODSol, N-TKN and N-NH3), and respirometric activity (i.e. BOD on solid samples suspended in liquid medium, for this study). The data set was obtained by analysing the parameters listed above for two RMSW and two BW, collected from three full-scale HSAD plants, and their respective digestates produced by the selected plants (i.e. altogether 4 wastes and 4 digestates). The principal component analysis showed that VS, COD, and TOC were partly redundant and that the set of parameters could be significantly reduced. Predicting anaerobic bioreactivity from single biochemical parameters such as the Van Soest fractions was not found relevant. On the opposite, the residual fraction RES and HSI were the most correlated to BMP and BOD. These two variables constitute good indicators for the description of the bioreactivity (and biostability) of the samples, and could be used to predict it.