Analysis of the combustion and pyrolysis of dried sewage sludge by TGA and MS

In this study, the combustion and pyrolysis processes of three sewage sludge were investigated. The sewage sludge came from three wastewater treatment plants. Proximate and ultimate analyses were performed. The thermal behaviour of studied sewage sludge was investigated by thermogravimetric analysis with mass spectrometry (TGA-MS). The samples were heated from ambient temperature to 800 degrees C at a constant rate 10 degrees C/min in air (combustion process) and argon flows (pyrolysis process). The thermal profiles presented in form of TG/DTG curves were comparable for studied sludges. All TG/DTG curves were divided into three stages. The main decomposition of sewage sludge during the combustion process took place in the range 180-580 degrees C with ca. 70% mass loss. The pyrolysis process occurred in lower temperature but with less mass loss. The evolved gaseous products (H-2, CH4, CO2, H2O) from the decomposition of sewage sludge were identified on-line. (C) 2013 Elsevier Ltd. All rights reserved.