Table 2.
Comparison of sludges in A/O, OD, and full-scale SBRs.
| Process | Anaerobic/oxic | Oxidation ditch | Full-scale SBR |
|---|---|---|---|
| Volumetric flow rate (m3 d−1) | 10,000 | 50,000 | 50,000 |
| Operating mode | Plug flow (A/O) | Continuous flow | Sequencing batch |
| Substrate change | Feast-famine | Completely mixed | Feast-famine |
| COD loading (kg m3 d−1) | 0.54 | 0.68 | 0.56 |
| Ammonium loading (kg m3 d−1) | 0.025 | 0.031 | 0.022 |
| Settling time (min) | 150 | 150 | 70–80* |
| MLSS (mg L−1) | 5471 | 5818 | 3946 |
| SVI30 (mL g−1) | 61.1 | 60.7 | 47.1 |
| MLVSS/MLSS | 56.3% | 57.2% | 62.4% |
| Settling velocity (m h−1) | 10.4 | 9.2 | 42.0 |
| EPS (PS, mg/g VSS) (PN, mg/g VSS) |
13.0 263.9 |
15.2 288.2 |
20.8 253.8 |
| COD removal efficacy (%) | 82.2 | 81.3 | 85.0 |
| NH4 +-N removal efficacy (%) | 94.3 | 94.8 | 95.8 |
| TN removal efficacy (%) | 25.3% | 22.7% | 59.6% |
*Settling time in full-scale SBR includes 30 min of effluent withdraw.
*Samples from anaerobic/oxic reactor, oxidation ditch, and full scale sequencing batch reactor were taken at the same time on September 8, 2011.