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

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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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