Thermal Hydrolysis

The HCHS Thermal Hydrolysis is a continuous operating thermal hydrolysis process installed to treat primary and/or secondary sludge prior it enters the anaerobic digestion section; iis not only a process for reducing sludge volume and disposal cost, but also a process to transform the sludge from waste to resource. With thermal hydrolysis, the complete elimination of pathogens is achieved, resulting in optimal sludge hygienization, while its dewaterability is increased.

Dewatered sludge is pre-heated with recycled saturated steam and then pressurized before beign transferred into the Reactor; the Reactor is the core of the system in which the sludge is kept at approx 165 °C and 6 bar for about 30 minutes by direct fresh steam injection. After the reactor, sludge discharge by means of flash nozzle causes a rapid pressure decrease with consequent damage and breacking of the cell walls. The hydrolysed sludge, decompressed to approximately ambient pressure is than introduced with or without dilution into the digester.

The main advantages of this technology are:-

• Reduction of sludge amount to be disposed
• Significant improved dewaterability
• Reduced volume of the downstream digesting section
• Increased biogas yield and quality
• Reduced viscosity of the sludge
• Reduced amount of water to be evaporated in the eventually downstream drying section
• Pathogen-free sludge according to Class A