Chemical Differentiation of Domestic Sewage Sludge and Cattle Manure Stabilized by Microbioreators: Study by Pyrolysis Coupled to Gas Chromatography Coupled to Mass Spectroscopy

The aim of the present study was to evaluate the chemical alterations in substrates of vermicomposts from domestic sewage sludge and from cattle manure, besides its quality as an organic fertilizer. Elemental and infrared analysis and UV-Vis spectroscopy were used for their characterizations. Chemical characteristics determined in the vermicomposts indicate that they can be used as organic fertilizers, mainly with regard to organic matter content, pH, C/N ratio, and nitrogen and phosphorus levels. The main constituents of the humic substances extracted from the vermicomposts were obtained by pyrolysis coupled to gas chromatography-mass spectrometry (GC/MS), showing that these compounds are quite similar, despite being produced by domestic sewage sludges or by cattle manure.