Sewage sludge is a byproduct of wastewater treatment that must be managed sustainably. One long-standing solution is the industrial incinerator known as the multiple hearth furnace (MHF). This proven technology is especially prominent in biosolid incineration, where the goal is volume reduction, pathogen destruction, and ash stabilization.
What is a Multiple Hearth Furnace?
A multiple hearth furnace is a vertical, refractory?lined steel cylinder containing stacked, rotating hearths. Dewatered sludge enters the top and slowly descends through zones dedicated to drying, combustion, and ash cooling. Temperatures commonly exceed 900?degrees Fahrenheit, driven by chemical heat from sludge and supplemental burners when needed.
Remaining ash is then removed via rabble arms and dropped into collection systems, significantly reducing sludge volume.
Advantages of Multiple Hearth Furnaces for Biosolid Incineration
The use of multiple hearth furnaces for sewage sludge incineration has many advantages; some of these include:
- Efficient Waste Volume Reduction
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Self-Sustaining Combustion
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Proven Longevity and Upgradeability
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Usable for PFAS Destruction
PFAS, also known as forever chemicals, continue to be a big environmental concern. News continues to come out about contaminated farmland and water sources throughout the United States. The EPA recently announced that major EPA actions would be taken to combat PFAS contamination.
Multiple hearth furnaces can flex temps up to 1832°F, providing more flexibility and wear to ensure the high temperature needed to remove PFAS. In addition, if parts need to be replaced due to high intensity use for PFAS removal, the cost of spare parts for a multiple hearth furnace is significantly lower than other potential methods.
Multiple hearth furnaces remain a time-tested solution for industrial incinerators, biosolid incineration, and sewage incinerator applications. Thanks to their robust design, long lifespan, and adaptability, they continue to play a critical role in modern sludge management. With proper emissions control, energy recovery, and periodic upgrades from experts like IFCO, these systems offer a resilient and sustainable path forward for wastewater treatment facilities.