The dewaterability of sewagesludge is improved by hydrothermaltreatment; however the solid hydrochar produced has to be improved in order to be used for energy production [1]. A effective technique that also increases dewaterability is hydrothermal co-carbonization of fuel additives and sewage sludge [2]. So, hydrothermal carbonization of sewage sludge including 10% charcoal, 10% oak sawdust, and 10% and 20% fir sawdust was accomplished [3]. The samples' physical and chemical characteristics were examined and contrasted before and after the treatment. Dewaterability tests using capillary suction time and filtering were carried out [4]. Hydrochars' fuel qualities, including thermal analysis, higher heating values, and ultimate and proximal analyses, were identified [5]. The operational risk indices were discovered based on the composition of the ash. Additionally, the complete combustibility index and the combustion kineticindex were computed [6].