A method and apparatus are disclosed for mixing sewage sludge with spent water-softener
lime in a ratio of approximately 10:1 on a wet basis. The mixture is introduced
to a rotary pre-dryer kiln and a rotary combuster kiln to kill pathogens. An ash
by-product and gases are thereby produced. The ash by-product can be disposed of
at much less cost or can be incorporated in a variety of applications such as an
aggregate substitute.
