Process for disinfection of sewage sludge

A process for treating sewage sludge with percent solids less than 20 percent comprises (1) contacting sewage sludge that contains undesirable microorganisms with at least one compound that produces methyl isothiocyanate in water to form a reaction mixture, (2) mixing the reaction mixture, and (3) maintaining the reaction mixture in a closed vessel for at least about two hours. After the reaction mixture is maintained in a closed vessel for the desired time, the closed vessel can be vented to the atmosphere for a time sufficient to dissipate residual methyl isothiocyanate from the reaction mixture.