The present invention relates to a method for efficiently incinerating waste material, particularly dewatered sludge, in a multiple hearth furnace by controlling the temperature of the individual hearths of the furnace within certain prescribed limits by modulating the amount of combustion air, and controlling...http://www.google.com.au/patents/US4453474?utm_source=gb-gplus-sharePatent US4453474 - Method for controlling temperatures in the afterburner and combustion hearths of a multiple hearth furnace
