The conventional defoulation of the sewage sludge is limited by the hydrolysis step (technical digestion limit). Treatment of the excess sludge with ultrasound leads to overcoming this limit. The digestion process is intensified and further dismantling is achieved. This reduces the amount of rotten residual sludge while increasing biogas production.
The degradation of the organic sludge fraction in conventional anaerobic sludge stabilization is limited by the speed-determining hydrolysis step. Rarely are grades of 50% achieved. This is due to the hard-to-reach bacterial biomass of the excess sludge. This is opened up (disintegrated) by sonication with Ultrawaves ultrasonic technology and is thus more readily available for the subsequent bio-enzymatic degradation process. Even with low energy inputs, ultrasound causes the flake structure to be decomposed and exoenzymes released. This increases the interface between the solid and liquid phase and thus facilitates the enzymatic attack of the active microorganisms.
A higher energy input leads to the digestion of bacterial cells, which releases cell ingredients 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 further degraded. As a major advantage, this results in a significantly increased production of biogas and a reduction in the amount of residual sludge to be disposed of. As a result of the lower residual organics, the dewatering of the sludge is additionally facilitated (lower flocculan eacement supplement) and increased (higher degree of dewatering).
This disintegration of the sludge reduces its viscosity. This is important for operational practice, as it facilitates the mixing of the fermenter content, which leads to noticeable energy savings.
Digestive containers that are at the limit of their load can be operated without any problems in the long term with the help of ultrasonic technology. In the case of new buildings, the rotting containers could be measured with a shorter residence time.