Production of bio-fuels by high temperature pyrolysis of sewage sludge using conventional and microwave heating

9 pages, 4 figures, 6 tables.-- PMID: 16473008 [PubMed].-- Printed version published Jul 2006.The pyrolysis of sewage sludge was investigated using microwave and electrical ovens as the sources of heat, and graphite and char as microwave absorbers. The main objective of this work was to maximize the gas yield and to assess its quality as a fuel and as a source of hydrogen or syngas (H2 + CO). Both gases were produced in a higher proportion by microwave pyrolysis than by conventional pyrolysis, with a maximum value of 38% for H2 and 66% for H2 + CO. The oils obtained were also characterized using FTIR and GC–MS. The use of conventional electrical heating in the pyrolysis of sewage sludge produced an oil that could have a significant environmental and toxicological impact. Conversely, microwave pyrolysis still preserved some of the functional groups of the initial sludge such as aliphatic and oxygenated compounds, whereas no heavy PACs were detected.The authors thank the Spanish Ministry of Science and Technology (Research Project PPQ2001-2083-C02-01) and FEDER for financial support. A. Domínguez is also grateful to FICYT (Asturias-Spain) for financial assistance.Peer reviewe