The Case for Variable Density: A New Perspective on Activated Sludge Settling
- 1 October 2007
- journal article
- research article
- Published by Wiley in Water Environment Research
- Vol. 79 (11), 2298-2303
- https://doi.org/10.2175/106143007x194347
Abstract
A new, simple method for directly measuring activated sludge density was developed and applied, and the effects of biomass density on activated sludge settling in full‐scale systems were evaluated. The driving force of sedimentation is the physical weight of the biological solids, but the role of biomass density in sedimentation has been largely ignored. Biomass density varied amongst treatment systems and this variability was correlated with settleability. Floc densities were approximately normally distributed within individual samples. Nonsoluble phosphorus content was a major contributor to density, and plants with enhanced biological phosphorus removal (EBPR) configurations generally had higher densities and better settleability than non‐EBPR plants with similar filament contents. These results suggest that future work may benefit from consideration of density as a factor affecting activated sludge settling.Keywords
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