Abstract: A system is described for producing small uniform pellets of predetermined size which are substantially free of fines from mechanically dewatered sewage sludge and a means for controlling odor from the production of said pellets. The system includes a process and apparatus for mixing the dewatered sludge with previously dried recycled particles of said sludge. Drying the mixture in a thermal drier, separating a substantial portion of the dried solids from the drier off-gas. Clarifying said separated solids to separate the pellets of predetermined size, oversized pellets, and undersized pellets and particles, mechanically crushing the oversized pellets and admixing the crushed oversized pellets with the undersized pellets and particles and recycling said mixture for mixture with incoming dewatered sludge to the drier. The off-gas from the mechanical separation process is then passed through a condenser to remove some of the water therein, and is routed to an afterburner wherein it is burned.

Abstract: A process is described for combining the disposal of sewage sludge and lime sludge economically by recalcining the lime sludge to product lime for municipal water treatment, and utilizing the excess heat from the recalcining process to dry and pelletize sewage sludge or to supplement the heat required to dry and pelletize said sewage sludge. The sewage sludge pellets then are produced in uniform sizes and have excellent value as a soil conditioner.