Applications: Sludge treatment

Conventional fermentation of sewage sludge is limited by the hydrolysis stage (technical digestion limit).

Treating excess sludge with ultrasound enables this limit to be overcome.

The digestion process is intensified, resulting in more extensive degradation.

This reduces the volume of digested residual sludge whilst increasing biogas production.

The digestion of the organic sludge fraction in conventional anaerobic sludge stabilisation is limited by the rate-limiting hydrolysis step.
Digestion rates of 50% are rarely achieved.
The reason for this lies in the hard-to-access bacterial biomass of the excess sludge.
This is broken down (disintegrated) by sonication using our ultrasonic technology with hard cavitation

and is thus more readily available for the subsequent biological-enzymatic digestion process.

Even at low energy inputs, ultrasound causes the floc structure to break down and exoenzymes to be released. This increases the interface between the solid and liquid phases, thereby facilitating enzymatic attack by the active microorganisms.
A higher energy input leads to the lysis of bacterial cells, releasing cellular contents and endoenzymes.
These enzymes further accelerate the degradation process.

The limiting hydrolysis step is overcome, the entire digestion process is intensified, and the organic fraction is reduced further.
A key benefit of this is a significant increase in biogas production and a reduction in the volume of residual sludge requiring disposal.
As a result of the lower residual organic content, the dewaterability of the digested sludge is also facilitated (lower flocculant addition)

and improved (higher degree of dewatering).
This disintegration of the sludge reduces its viscosity.
This is important in operational practice, as it facilitates the mixing of the digester contents, leading to significant energy savings.

Digesters operating at full capacity can continue to operate without any problems in the long term with the aid of ultrasonic technology.
In new facilities, digesters could be designed to operate with a shorter retention time.