CNP Process: PONDUS™ (THP)

What is PONDUS Thermal Hydrolysis Process (THP)?

PONDUS, an alkaline process, utilizes low grade heat (140 °F to 160 °F) and sodium hydroxide for sludge hydrolysis. A typical PONDUS system consists of a hydrolysis reactor, hot water heat exchanger, chemical dosing station, pumps, instrumentation and controls. PONDUS reduces sludge viscosity, enhances biogas production and improves sludge dewaterability.

Awards Won:

2019 Frost & Sullivan Product Leadership Award for the North American Sludge Treatment
2018 Utility of the Future Today Recognition Program for the Kenosha WWTP Optimization Project
2017 W&WD Top Project for the Kenosha WWTP Optimization Project
2017 ACEC Grand Award Winner for the Kenosha WWTP Optimization Project

PONDUS Step-By-Step

[1] Thickened WAS is mixed with a small dose of [2] caustic soda (1.75 l/m3).

[3] Sludge is heated in a loop through a high-efficiency heat exchanger.

[4] Sludge is fed into PONDUS and goes through hydrolysis. The sludge is heated with 140 °F to 160 °F water from a Combined Heat and Power (CHP) unit or boiler. Retention time may differ in reactor zones due to varying sludge properties. The reactor operates under atmospheric pressure and is connected to the atmosphere or bio-filter. After the hydrolysis process, sludge leaves the reactor close to a neutral pH level and the remaining thermal energy can be used in the anaerobic digester [7].

[5] Thickened primary sludge and hydrolyzed sludge is mixed to achieve an ideal mesophilic temperature of the combined sludge and then pumped into the digester [7]. If needed, additional heat can be brought into the digester through a [6] heat exchanger.

The PONDUS Difference

No heat exchangers needed to cool sludge after hydrolysis to maintain an optimum digester temperature
No pressure vessel required
- Safer operation
- Specialized steam operator is not necessary
- Reduces operating and energy costs
Combination of caustic soda (NaOH) and heated water, 140 °F to 160 °F, break down the cell walls
Minimal equipment needed: high-efficiency heat exchanger, progressive cavity pumps and a reactor operating under at atmospheric pressure

PONDUS is Simple to Operate

PONDUS is designed to utilize low grade heat (from hot water), rather than steam, as a heat source for sludge hydrolysis. A certified steam boiler license is not required to operate the system. PONDUS’ design allows it operate the atmospheric pressure without involving a pressurized vessel. Maintaining PONDUS is easy. Typical maintenance includes: pump maintenance, heat exchanger cleaning, and sodium hydrolyzed refilling.