Hygienisation of surplus activated sludge by hydrodynamic cavitation

Abstract

The success of an effective process of disintegration is the application of physical or chemical methods of the destruction of the cell wall which consequently becomes fragmented and the intracellular matters are released into the surrounding liquid. The purpose of the conducted experiments was to demonstrate possibilities of application of the hydrodynamic in the bacteriological hygienisation of surplus activated sludge. The confirmation of the effectiveness of the bactericidal activity of hydrodynamic cavitation was the number of bacteria grown on agars before and after hygienisation process. Selective and basic beddings have been used in the research. The bacterial culture has lasted approximately 24 to 48 hours. After the period of incubation the colonies produced have been counted and initially identified. Based on the microbiological analyses a significant reduction in an overall number of bacteria and pathogenic bacteria belonging to the family Enterobacteriaceae and to the pathogenic species Staphylococcus has been noticed. The overall number of bacteria decrease about 80% after 45 minutes of disintegration of surplus activated sludge. Pathogenic bacteria belonging to the family Enterobacteriaceae: lactose-positive and lactose-negative decrease about 93% and 92%, respectively. Reducing the number of Salmonella bacteria was 100% after 45 minutes of disintegration processes. Reduction bacteria of species Staphylococcus were about 93% for mannitolo-positive and 92% for mannitolo-negative.