Influence of Torrefaction on Sewage Sludge

Abstract

Sewage sludge (SS) from sewage treatment plants has been seen as a waste for decades and little attention to investigate the potential and its beneficial product. SS contain a large amount of recoverable energy; however, it has high moisture, ash, heavy metals, and organic contents. Thus, the goal of this research is to use torrefaction to produce upgraded or torrefied SS. The proximate and ultimate analysis was used to determine the physical and chemical characteristic of raw SS. Torrefaction was performed through inert atmosphere in fixed bed reactor. According to the findings, at torrefaction temperature of 300 °C, torrefaction had improved the quality of raw SS, increasing its fixed carbon content by 47.8%, and its moisture content by 61.3%. The optimum temperature for torrefaction was at 300 °C with holding time of 60 minutes. This study improved the quality of sewage sludge to be utilised in subsequent thermochemical conversion.