Rheological characterization of sludge in divided granular-like and pasty states using a granular rheometer

Structural changes during sludge treatments impact flowability and raise severe technical issues. In this study, the consistency is analysed using thread rolling test. Transition from pasty to granular-like material occurs at a total solid (TS) content of 43 wt%. A granular rheometer used characterize sludge's over wide range TS content. The typical powder-like behaviour recorded whatever contents. All shear stresses/consolidations curves exhibit linear increase, highlighting contribution frictional interactions. Fitting Mohr-Coulomb failure criterion these emphasizes substantial rise interactions Flow functions are determined Mohr's circle stress analysis. According classification powder flowability, analogous that very cohesive powders for 25.5 < wt% while lower higher contents, behaves like powders.