Thermal Gasification: A Feasible Solution for Sewage Sludge Valorisation?

• Published in: Chemical engineering & technology Vol. 26; no. 9; pp. 941 - 945
• Main Authors: Ferrasse, J.-H., Seyssiecq, I., Roche, N.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 10.09.2003; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Exact sciences and technology; Gasification; Other industrial wastes. Sewage sludge; Pollution; Sewage sludge; Wastes; Thermochemical treatment; Gasification; Waste treatment; Upgrading; Sewage sludge
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.200301813

The proliferation of wastewater treatment plants has become essential to ensure the protection of the natural environment. As a consequence, the production of waste by‐products, namely sewage sludge, has increased together with both the unit efficiency levels and with the number of wastewater treatment plants. Since dumping is no longer allowed in the EU, the processes mainly used to treat sewage sludge are agricultural spreading and incineration. However, due to the constant increase in production, it has became essential to find alternative methods of treatment. Considering the chemical composition of sludge, some new thermal processes of treatment have recently been considered by researchers. Thermal gasification is one method that could be of significant interest. Dried sludge composition is sufficiently close to the that of classical biomass (such as wood, rice, etc.) to make sludge treatment in a gasifier feasible. In this paper we discuss how gasification technologies could be transposed to the treatment and valorisation of sludge. Although this process seems attractive, it will also be demonstarted that much experimentation remains to be conducted on a laboratory and pilot scale. The disposal of excess sludge from wastewater treatment plants (WWTP) represents a rising challenge for the environment. An attempt has been made to demonstrate how gasification technologies could be transposed to the treatment and valorisation of wastewater sewage sludge. Due to the simultaneous production of heat and electricity WWSS gasification could be one of the cheapest ways to treat this waste.