In the design of Secondary Settling Tanks (SST) the detailed inner hydrodynamic behaviour and the operation parameters are still often poorly addressed. Coupled fine scale flow and concentration measurement in operating tanks can give more insight into the interconnected flow and concentration pattern, furthermore, provide validation data for advanced numerical models. The latter can serve then as design tool to optimize the performance by finding proper tank geometry, sludge recycling ratio etc. This paper presents the first results of such an investigation of one of the SSTs at the Waste Water Treatment Plant of Graz. Acoustic Doppler velocity and optical turbidity measurements gave both overall information and novel details on the wavy character of the sludge-water interface. FLUENT-based axisymmetric flow and coupled activated sludge transport modelling could then reasonably reproduce measured distributions and patterns, promising for future modelling in order to reach enhanced performance.
|Translated title of the contribution||Measuring and modelling physical processes in secondary settling tanks|
|Number of pages||8|
|Journal||Osterreichische Wasser- und Abfallwirtschaft|
|Publication status||Published - Jan 1 2005|
ASJC Scopus subject areas
- Water Science and Technology
- Fluid Flow and Transfer Processes