Gasification as a new thermal processes of sewage sludge utilization

Disposal of wastewater treatment sludge is a pressing environmental problem in nowadays, which is aggravated by its accumulation around the world. The imposition of more stringent legislation governing the disposal and utilization of sewage sludge, coupled with the growth in its generation and the loss of traditionally accepted disposal routes, has prompted a drive for alternative uses for sewage sludge. Considering the chemical composition of sludge, some new thermal processes of treatment have recently been considered by researchers. Thermal gasification is one innovative method that could be of significant interest. This paper seeks to review the published research in this field: it covers the characteristics of sewage sludge, the principle of gasification; the applications of sewage sludge in gasification process; the tar elimination and fate of heavy metals in biomass gasification processes.