Rapid increase in world population and economic growth, improvements in living standards after the industrialization of the world brought about high demand of energy.In the last two decades, extensive work has been done for alternative and sustainable sources and technologies to meet up current and future energy demand such as solar energy, wind energy, hydro and biofuels energy.One of the viable biomass sources available in Malaysia is Domestic wastewater sludge.Further study on this biomass is required to promote as the biomass fuel.This study focused on the production of volatile and char yield during pyrolysis and combustion with particle size range between 0.4 mm and 2.0 mm and heating rate (5, 10, 15, 20, 30, 50 and 100 K/min) by using thermogravimetric analysis.Based on the finding, the total volatile shows a tendency to decrease when the heating rate increase with the highest value was 84.51.However, the highest char was produced at the highest heating rate was 23.80.The lowest heating rate is favourable since produce high volatile matter content and low char content. © 2023, Institute of Technology PETRONAS Sdn Bhd.