Carbon- and nitrogen-containing compounds in composted urban refuses

✍ Scribed by S.J. González-Prieto; M. Carballas; M.C. Villar; M.C. Beloso; A. Cabaneiro; T. Carballas

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 718 KB
• Volume: 45
• Category: Article
• ISSN: 0960-8524
• DOI: 10.1016/0960-8524(93)90099-w

✦ Synopsis

The composition of the organic matter off our cornposted urban refuses (one of them amended with CaCO 3 in the composting process) from Spanish industrial composting plants was studied. Fundamental components and C-bearing compounds (humic substances) were assessed by classical fractionation methods; N-bearing compounds were determined by acid step-wise hydrolyses. Cellulose and hemicelluloses largely predominated over lignin, which was the second important component, .followed by water-soluble compounds, the content of lipids being very low. Water-soluble compounds represented 3-14% of the organic C. Alkali-soluble compounds were quite low since humic compounds (humic and fulvic acids) only represented about 17% of the organic C (24% in the amended compost); humic acids predominated over fulvic acids, the most polymerized compounds being higher than the less polymerized ones. The predominant fraction (about 70% of the organic C) was the insoluble one which comprised unhumified compounds, insolubilizable humin, microbial humin (1.4-9.0% of the organic C) and residual humin (20-40% of the organic C). The extraction percentage was very low whereas the degree of humification was close to 50%. About 85% of the organic N was hydrolysable. Hydrolysable unidentified-N was the predominant organic N fi~rm, followed by a-aminoacid-N. NHa+-N from organic compounds and hexosamine-N were very small and amide-N was not detectable. According to the percentage of humification the four composted refuses were stabilized materials.