CHEMICAL AND BIOLOGICAL CHARACTERIZATION OF ORGANIC-MATTER DURING COMPOSTING OF MUNICIPAL SOLID-WASTE

Composting of municipal solid waste (MSW) was studied in an attempt to elaborate transformations of organic matter (OM) during the process a nd define parameters for the degree of maturity of the product. Compos ting was performed in I-m(3) plastic boxes and the following parameter s were measured in 13 samples during 132 d of composting: temperature, C/N ratio, ash content, humic substance contents, and fractions (humi c acid, fulvic acid, and nonhumic fraction-RA, FA, and NHF, respective ly). Spectroscopic methods (CPMAS C-13-NMR, DRIFT) were used to study the chemical composition of the OM. A bioassay based on growth of cucu mber (Cucumis sativus L. cv. Dlila) plants was correlated to other par ameters. The C/N ratio and ash content showed a typical high rate of c hange during the first 60 d and reached a plateau thereafter. The HA c ontent increased to a maximum at 112 d, corresponding to the highest p lant dry weight and highest 1650/1560 (cm(-1)/cm(-1)) peak ratios calc ulated from DRIFT spectra. C-13-NMR and DRIFT spectra of samples taken from the composting MSW during the proc ess showed that the residual OR;I contained an increasing level of aromatic structures. Plant-growt h bioassay, HA content, and the DRIFT spectra indicated that MSW compo st described in this study, stabilized and achieved maturity after abo ut 110 d.