Humic-acid transformation during composting of municipal solid waste

Composting of solid municipal waste (MSW) was studied in an attempt to characterize concomitant transformations of humic acid (HA). Mass balance was calculated for each compost sample during composting, and cross polarization magic angle spinning (CPMAS), C-NMR, and Fourier transform infrared spectroscopy measurements were employed on the purified HAs and core-HAs. The mass balance data, together with the spectroscopic analyses indicate that one of the major HA transformation processes occurring events during the process is the degradation of the coating materials, yielding the core HA structure.