Simulating ultrasonic activated sludge disintegration for excess sludge reduction in SBR systems

This paper presents an integrated mathematical model that is capable of predicting and assessing the impact of ultrasonic (US) treatment on the excess activated sludge production in a sequencing batch reactor (SBR) system. Such a model can be exploited to maximize the excess sludge reduction while minimizing the US operational costs in biological wastewater treatment systems. Biological processes in the reactor are simulated in Matlab®/Simulink by the ASM1 model into which two algebraic equations, which capture the US treatment, are integrated. Validation data series come from a pilot plant installed at two locations, i.e., at a communal wastewater treatment plant and at an industrial production site of a food flavor producing factory in Haasrode both in the Flanders region in Belgium. The results show that the excess sludge reduction from the SBR can be correctly predicted. A reduction of nearly 42% for the communal case study can be reported, while preliminary results for the industrial case study, characterized by a very high organic loading, are even more promising.