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thermal hydrolysis
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A detailed diagram shows the process of sludge treatment and disposal in wastewater treatment, with labeled tanks, pipes, and equipment illustrating steps like flotation, pulping, hydrolysis, digestion, dewatering, and biogas production.
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thermal hydrolysis

chemistry
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A detailed diagram shows the process of sludge treatment and disposal in wastewater treatment, with labeled tanks, pipes, and equipment illustrating steps like flotation, pulping, hydrolysis, digestion, dewatering, and biogas production.
sewage sludge treatment Mixed sludge received from secondary wastewater treatment is passed through a dissolved-air flotation tank, where solids rise to the surface and are skimmed off. The thickened sludge is pulped with steam, then passed to thermal hydrolysis, where large molecules such as proteins and lipids are broken down under heat and pressure. The hydrolyzed sludge is passed through a flash tank, where a sudden drop in pressure causes cells to burst, and then to anaerobic digestion, where bacteria convert dissolved organic matter to biogas (which can be used to fuel the treatment process). Digested sludge is passed through a dewatering step; the dried solids are disposed of, and the water is sent back to secondary treatment.

Thermal hydrolysis is a process that breaks down large molecules using heat, often as a preliminary step before digestion in wastewater treatment. In this process, sludge is mixed with steam and heated under pressure, causing hydrolytic reactions. A sudden drop in pressure then bursts cell walls, breaking down solid matter. This hydrolyzed sludge is then sent for anaerobic digestion, where bacteria further decompose organic materials into stable substances, reducing sludge volume and destroying pathogens. This method can convert a higher percentage of solid matter into liquids and gases compared to traditional digestion, potentially leading to increased biogas production for energy.1

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7 Britannica Sources
  1. heat of reaction
  2. wastewater treatment - Digestion
  3. chemical reaction - Energy considerations
  4. pyrolysis
  5. clay mineral - High-temperature reactions
  6. chemical reaction
  7. hydrolysis

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