| Abstract |
The knowledge of rheological parameters in sludge management is essential due to the unit operations they are subjected to. The rheological properties of sewage sludge are best described by mathematical models on the basis of which flow curves and viscosity curves are drawn. If they are omitted when designing, they may contribute to problems related to the operation of sludge management systems. Rheological parameters are also an important control indicator for the dewatering and stabilization processes. This article presents the results of rheological tests of excess and digested sludge, which were subjected to thickening after chemical conditioning with polyelectrolytes. The rheological analysis consisted in determining the stresses, viscosity, flow limits and rheological models for the sludge with different amounts of excess water removed. The conducted research showed that with the reduction of sludge hydration, the viscosity and shear stresses (flow limits) increased. The highest values were recorded for the sludge for which the greatest amount of excess water was removed. |
