title: Clay-sewage sludge co-pyrolysis. A TG-MS and Py-GC study on potential advantages afforded by the presence of clay in the pyrolysis of wastewater sewage sludge.
abstract: Wastewater sewage sludge was co-pyrolyzed with a well characterized clay sample, in order to evaluate possible advantages in the thermal disposal process of solid waste. Characterization of the co-pyrolysis process was carried out both by thermogravimetric-mass spectrometric (TG-MS) analysis, and by reactor tests, using a lab-scale batch reactor equipped with a gas chromatograph for analysis of the evolved gas phase (Py-GC). Due to the presence of clay, two main effects were observed in the instrumental characterization of the process. Firstly, the clay surface catalyzed the pyrolysis reaction of the sludge, and secondly, the release of water from the clay, at temperatures of approx. 450-500 °C, enhanced gasification of part of carbon residue of the organic component of sludge following pyrolysis. Moreover, the solid residue remaining after pyrolysis process, composed of the inorganic component of sludge blended with clay, is characterized by good features for possible disposal by vitrification, yielding a vitreous matrix that immobilizes the hazardous heavy metals present in the sludge.
authors.affiliation: Department of Materials Engineering and Industrial Technologies, University of Trento, via Mesiano 77, 38100 Trento, Italy. marco.ischia@ing.unitn.it
authors.forename: Marco
authors.initials: M
authors.lastname: Ischia
authors.forename: Roberto
authors.initials: R
authors.lastname: Dal Maschio
authors.forename: Maurizio
authors.initials: M
authors.lastname: Grigiante
authors.forename: Marco
authors.initials: M
authors.lastname: Baratieri
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D002849:Chromatography, Gas; D000077215:Clay; D017745:Incineration; D013058:Mass Spectrometry; D012722:Sewage / Q000737:chemistry*; D013818:Thermogravimetry; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000538:Aluminum Silicates; D012722:Sewage; D000077215:Clay