B Ceccanti

Evaluation of the organic matter composition of raw and composted municipal wastes

Abstract The organic matter contained in ten municipal wastes (7 raw residues and 3 composts) was evaluated by studying chemical parameters. The structural-chemical composition of organic matter was also studied by pyrolysis-gas chromatography (Py-GC) and the qualitative properties of organic matter were investigated by isoelectric focusing (IEF). The chemical indices employed (biodegradability index and water soluble C/total N ratio) were found to be useful for distinguishing raw organic matter from composted one, although they did not enable to differentiate between organic matter derived from municipal solid wastes (MSW) and that from aerobic sewage sludges (SS), The structural chemical composition of the organic matter extracted from the wastes differed depending on the groups studied (raw MSW, raw SS, and composts) when the most aliphatic pyrolytic compounds (acetic acid and furfural) were considered; these were less abundant in the composts, as acetic acid predominated in sewage sludges and furfural...

Fractionation and Characterization of Humic Substance Fractions with Different Molecular Weights, Obtained from Animal Wastes

Abstract The humic substances contained in an animal organic waste were extracted and the total extract separated into three humic fractions with different molecular weights (low, F1 104). The C content was highest in F2, the same fraction also showing the lowest N content. The molecular weight of the humic fractions influenced the electrical conductivity, the highest molecular weight resulting in the lowest degree of electrical conductivity. Membrane-controlled ultrafiltra-tion (the method used to separate the various fractions from the whole extract) was also suitable for purifying such enzymes as phosphatase and β-glucosidase: the total activity obtained from the three fractions was considerably greater than that determined in the whole extract, Pyrolysis-gas chromatography (Py-GC) applied to the whole extract and humic fractions showed that in the F3 fraction (highest molecular weight) benzene was the major fragment while ...