Sewage Sludge

Control of bulking sludge and scum by ultrasonic treatment

Ultrasonic treatment is a proven method for the stabilisation of activated sludges. The process developed, which has been tested in the laboratory and in pilot installations, is mobile and can be applied in sewage treatment plants on a seasonal and short-term basis.

Summary


In many sewage treatment plants which use biological methods for the removal of nutrients, filamentary micro-organisms will form at regular intervals in activated sludge which will change the structure of the latter to the extent that substantial operating problems and the impairment of biogas production will ensue.  The dewatering and disposal of biologically unstable sludges generates annual costs of the order of 200 million Euros.

The object of this project was the development of a commercially viable process for the control of bulking sludge and scum by ultrasonic treatment.

To this end, a high capacity ultrasonic reactor housed in a container has been constructed as part of a mobile treatment installation.  Five 200-litre digestion tanks have been installed in the container in order to investigate the impact of the ultrasonic treatment of bulking sludges upon anaerobic stabilisation.

Results:

  • A flexible and mobile process has been developed which can be applied in sewage treatment plants on a seasonal and short-term basis.
  • The digestion process is stable, with a slight improvement in the degradation of organic substances.  The reintroduction of filamentary organisms into the sewage cycle through the recirculation of turbid water can be virtually eliminated.
  • A definitive cost assessment of this process will not be possible until it has been applied on an industrial scale.  Specific costs are of the order of two to three Euros per cubic metre of bulking sludge.

Project Participants

Implementing Institutions

Hamburg University of Technology

Cooperation Partner

Sonotronic Nagel GmbH

More Project Information

Project title: Control of bulking sludge and scum by ultrasonic treatment

Project number: 02WA0053

Project period: 2001 - 2003

Project region: Germany (Hamburg)

Project contact:

Herr Prof. Neis
This email address is being protected from spambots. You need JavaScript enabled to view it.
49 40 42878 3107

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Source: German National Library of Science and Technology Hannover (TIB)