What process is used to move sludge cake through a multiple-health furnace?

The correct answer involves the process known as rabbling, which is specifically designed to move sludge cake through a multiple-hearth furnace. Rabbling refers to a mechanical process where a series of arms or rakes push and stir the material, allowing it to be evenly distributed and exposed to the heating elements within the furnace. This action ensures uniform treatment of the sludge as it progresses through the different hearths of the furnace.

The efficiency of rabbling is crucial in a multiple-hearth furnace operation, as it helps facilitate the drying, oxidation, and eventual conversion of sludge into a more manageable, reduced volume. By keeping the sludge in motion, rabbling also prevents clumping and allows for consistent exposure to the high temperatures required for effective treatment.

Understanding this process emphasizes the importance of mechanical movement in waste treatment systems, highlighting how it plays a significant role in enhancing the overall effectiveness of sludge processing.