Quantifying inhomogeneous mixing
An oxidation ditch installed with surface aerators was modeled using CFD combined with activated sludge model (CFD-biokinetic model).
Plant's performance under different operational conditions was evaluated in terms of oxygen transfer and ammonium removal.
- Surface aerators due to their design limitations have a significant impact on oxygen transfer
- Ammonium concentrations tend to accumulate at the bottom due to lower dissolved oxygen levels
- Using more aerators do not lead to significant improvement in ammonium removal
- Performance of the oxidation ditch could be improved by installing better aerators or devising a better aeration control strategy