The influence of mechanical and thermal disintegration on gravitational separation of surplus sludge

Abstract

The primary effect of sewage sludge disintegration process is the physical, chemical or biological change of their structure, which causes destruction of flocs, fragmentation of microbial cells and thus release of cell contents into the surrounding liquid. Pre-treatment of the sludge can be used for the process of thickening and dewatering of sludge. In this paper, the influence of hydrodynamic, microwave and freezing/thawing disintegration on selected properties of gravitational surplus activated sludge, were assessed. The scope of the research included the parameters characteristic of the sedimentation process, ie sludge density index (SDI), sludge volume index (SVI), sludge thickening speed (v), sludge concentration (Ci) and changes in the liquid phase of sludge chemical oxygen demand (SCOD) and turbidity. The obtained results as well as performed calculations have confirmed the impact of used disintegration in terms of improving the properties of surplus activated sludge.