The aim of the research was to analyze the composting process with respect to changes in some physical and physicochemical properties of the organic part of municipal solid waste and willow and hay biomass mixture. The dynamics of changes in cation exchange capacity CEC values in relation to the base value of the initial materials of both tested composts were higher for municipal solid wastes compost (MSWC) compost than for willow biomass compost (WBC). The dynamics of pH changes were similar in the tested types of compost and were rather small during the process of composting, regardless of the type of organic residues and initial reaction. During composting process, the transformation of organic matter and mineral components slows down after reaching a stabilization phase.
The aim of the study was to assess the transformation of humic substances during composting of biomass of energetic plants and municipal solid waste. The type of the organic material to be composted and the type of technology used affect the course of the humic substances transformation and formation of compost maturity parameters. Compost produced from the mixture of energetic willow and hay biomass contained humic substances with higher share of low-molecular fractions and lower share of humic acids in total organic carbon than those produced from municipal solid wastes. Obtained results also showed that insoluble alkali fraction plays an important role in humification process by its convertion to a new humic substances. Share of humic and fulvic fractions in relation to the total organic carbon appears to be reliable indicator of composting as a process of enhancing organic matter humification.