Effects of ultrasonic disintegration of excess sludge obtained in disintegrators of different constructions

  • Ewa Zielewicz, Malwina Tytła
  • Environmental Technology, March 2015, Taylor & Francis
  • DOI: 10.1080/09593330.2015.1024759

Effects of UD of excess sludge obtained in disintegrators of different constructions

What is it about?

The effects obtained directly after ultrasonic disintegration depend on many factors and can be grouped in two main categories: factors affecting the quality of sludge and those associated with the construction of disintegrators and its parameters. The ultrasonic disintegration research was carried out using three types of structural solutions of disintegrators. Two of them, that is, WK-2000 ultrasonic generator (P = 400 W) working with a thin sonotrode and WK-2010 ultrasonic generator (P = 100–1000 W) working with a new type construction emitter lens sonotrode, were compared with the influence of a washer with a flat emitter.

Why is it important?

The ultrasonic disintegration of excess sludge is placed after the mechanical thickening but before the digestion tanks in order to intensify the process of sludge stabilization. The effects obtained directly after ultrasonic disintegration depend on many factors and can be grouped in two main categories: factors affecting the quality of sludge and those associated with the construction of disintegrators and its parameters.

Perspectives

Malwina Tytła
INSTITUTE OF ENVIRONMENTAL ENGINEERING POLISH ACADEMY OF SCIENCES in Zabrze

The idea of ‘green energy’, very popular at present, is one of the reasons why the intensification of the fermentation process (to increase biogas production among others) has become so interesting. Therefore, wastewater treatment plants (WWTPs) start to introduce technologies (based on mechanical, thermal, chemical or enzymatic disintegration) to initially condition excess sludge (produced during biological sewage treatment) before it enters fermentation tanks. The mechanical technologies are the most common and technically advanced, including the ultrasonic techniques using low frequencies and high power. The active influence of ultrasonic field on excess sludge has been proposed as a strategy to accelerate the fermentation in many WWTPs in Europe. Despite this fact, there is still a great need to carry on research, because the criteria for selecting the size and operational characteristics of ultrasonic equipment in terms of expected effects of disintegration have not been specified so far. The investigations have shown that in the same sludge, using the same value of volumetric energy, the resulting effect depends on the construction of the ultrasonic disintegrator, that is, design of the head and the ratio between the field of the emitter and the field of the chamber in sonicated medium.

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http://dx.doi.org/10.1080/09593330.2015.1024759

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