Abstract: A method and apparatus for injecting sludge into a kiln includes a pump for pumping sludge, an attrition segment for attriting the sludge into smaller particles, and a conduit enclosing the attrition segment for entraining the particles in a stream of compressed air to carry the particles into a kiln. In the preferred embodiment, the attrition segment includes a perforated member, preferably comprising a plurality of perforated tubes which project jets of compressed air radially inwardly to slice the sludge mass within the segment into smaller particles. As the particles exit the attrition segment, they become entrained in a stream of compressed air flowing through the air conduit enclosing the attrition segment and are carried into the kiln.