Thermal Degradation of Malaysian Domestic Wastewater Sludge (DWS) Using Thermogravimetric Analysis Method

Abstract

Domestic Wastewater Sludge (DWS) is the waste generated from the wastewater treatment plant. Recently, the potential energy from wastewater effluents has become an interest among researchers due to high potential to be converted into energy and reduce harmful emission compared to fossil fuel. This study was aimed to study the effect of heating rates and particle size on Domestic Wastewater Sludge (DWS) by using thermogravimetric analysis (TGA) method. In this study, the sample of DWS was thermally dried using thermal dryer to reduce the moisture content until below than 20% for conversion into fuel. After that, the sample of DWS was analyzed using a non-isothermal TGA with a continuous flow of oxygen at a rate of 30 mL/min with temperature from room temperature which is 30°C to 800°C. There are three sample particle sizes ranging between 0.5 mm to 1.5 mm, and heating rate between 5 K/min to 20 K/min were used in this study. Based on the results from TGA analysis, the particle size does not have any significant effect at first, however it started to separate explicitly when the temperature getting increases. In addition, the sample size of DWS may affect the reactivity and the combustion performance caused by the heat transfer and temperature gradient. Besides that, it can be concluded that the TG and the peak of derivative thermogravimetry (DTG) curves have a tendency to change at high temperature when heating rate is increased because of the limitation of mass transfer and the delay of decomposition process.