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Characterization of Dissolved Organic Matter Extracted from Composted Municipal Solid Waste
Author(s) -
Chefetz Benny,
Chen Yona,
Hadar Yitzhak,
Hatcher Patrick G.
Publication year - 1998
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1998.03615995006200020005x
Subject(s) - chemistry , dissolved organic carbon , fractionation , fraction (chemistry) , magic angle spinning , nmr spectra database , compost , organic matter , humic acid , carbon 13 nmr , nuclear magnetic resonance spectroscopy , organic chemistry , environmental chemistry , spectral line , ecology , fertilizer , physics , astronomy , biology
The properties and transformation of dissolved organic matter (DOM) extracted from municipal solid waste compost at five stages of composting were studied using a chemical fractionation scheme. We fractionated the DOM into hydrophobic or hydrophilic neutrals, acids, and bases, and obtained solid‐state cross polarization magic angle spinning (CPMAS) 13 C‐nuclear magnetic resonance (NMR) spectra of the unfractionated DOM and of the different fractions. The hydrophobic acid (HoA) fraction was the dominant hydrophobic fraction, exhibiting a moderate increase during composting. The hydrophobic neutral (HoN) fraction increased sharply while the hydrophobic bases (HoB) fraction decreased during composting. The hydrophilic neutrals (HiN) represented the major fraction of the hydrophiles until 120 d of composting, decreasing thereafter by 38%. The 13 C‐NMR spectra of the unfractionated DOM revealed an increasing level of aromatic structures in the residual DOM with composting time. The 13 C‐NMR spectra of the HoA fraction suggested a polyphenol‐humic structure, whereas the HoN spectra exhibited strong aliphatic features. The spectra of the HiN fraction confirmed its polysaccharide nature and the hydrophilic bases (HiB) fraction contained mainly proteins and carbohydrate‐amino complexes. A comparison between the 13 C‐NMR spectra of HoA and fulvic acid (FA) indicated the former to be the most soluble FA fraction. The steady DOM concentration and the relative decrease of HiN as the HoA and HoN fractions increased indicates that DOM at the final stage of composting contained less bioavailable organic matter and more macromolecules related to humic substances. The constant level of DOM observed during the curing and maturation stages represents a steady‐state situation during which the chemical composition is continually changing.