<p>A method for retreating dewatered sludge in a semi-solid state having a water content of 70% - 85%, comprising the following steps: (1) adding a drying agent into the dewatered sludge, and mixing by stirring, to obtain a mixed sludge having a water content of 50% - 60%; and (2) drying the mixed sludge to obtain a dried granular sludge having a water content equal to or less than 45%.</p>
