However, it is not possible to achieve this aim by means of the “classical” fermentation process, in spite of mature technologies. Additional expenditures, such as the acceptance and fermentation of high energy value co-substrates in terms, are one of the options which are increasingly used. A further method, which is highly efficient and linked to low costs is the disintegration of sewage sludge by means of ultrasound. It is precisely the ultrasonic treatment of the difficult to ferment surplus sludge which breaks up the flocculated structure and opens up the cells, resulting in a significant increase in efficiency and in process optimisation of the treatment plant.
You will find a detailed description of the cavitation effect under: