Table 1.
Study design and operational data of the MBBR
| Period I | Period II | Period III | Period IV | Period V | Period VI | |
|---|---|---|---|---|---|---|
| Operational set‐up | ||||||
| Time (d) | 1–55 | 62–99 | 106–133 | 136–189 | 195–258 | 262–302 |
| NH4‐N infl (mg l−1) | 496 ± 32 | 249 ± 14 | 170 ± 19 | 129 ± 11 | 86 ± 8 | 43 ± 2 |
| COD infl (mg l−1) | 313 ± 36 | 174 ± 7 | 155 ± 26 | 84 ± 9 | 56 ± 4 | 48 ± 8 |
| HRT (d) | 3.3 ± 0.2 | 3.2 ± 0.0 | 3.2 ± 0.0 | 2.3 ± 0.1 | 1.6 ± 0.0 | 0.8 ± 0.0 |
| NLR (g‐N m‐2 d−1) | 0.75 ± 0.03 | 0.39 ± 0.02 | 0.26 ± 0.03 | 0.29 ± 0.02 | 0.28 ± 0.03 | 0.26 ± 0.02 |
| pH | 7.9 ± 0.12 | 7.7 ± 0.09 | 7.8 ± 0.08 | 7.5 ± 0.19 | 7.1 ± 0.07 | 7.2 ± 0.12 |
| DO (mg l−1) | 0.93 ± 0.08 | 0.67 ± 0.04 | 0.64 ± 0.07 | 0.82 ± 0.25 | 0.49 ± 0.06 | 0.48 ± 0.10 |
| Reactor performance | ||||||
| NH4‐N effl (mg l−1) | 311 ± 70 | 136 ± 21 | 119 ± 12 | 63 ± 22 | 31 ± 10 | 27 ± 5 |
| NO2‐N effl (mg l−1) | 12.5 ± 5.6 | 6.0 ± 5.7 | 2.2 ± 1.0 | 2.8 ± 1.4 | 1.6 ± 0.7 | 1.8 ± 0.3 |
| NO3‐N effl (mg l−1) | 98 ± 41 | 33 ± 23 | 8 ± 4 | 17 ± 13 | 21 ± 7 | 9 ± 6 |
| COD effl (mg l−1) | 281 ± 15 | 153 ± 19 | 118 ± 8 | 67 ± 14 | 53 ± 8 | 40 ± 6 |
| ARR (g‐N m−2 d−1) | 0.28 ± 0.10 | 0.18 ± 0.04 | 0.11 ± 0.07 | 0.14 ± 0.05 | 0.18 ± 0.04 | 0.10 ± 0.04 |
| NRR (g‐N m−2 d−1) | 0.11 ± 0.06 | 0.12 ± 0.03 | 0.09 ± 0.07 | 0.10 ± 0.03 | 0.10 ± 0.03 | 0.03 ± 0.03 |
| NO3 production (%) | 51 ± 19 | 28 ± 16 | 15 ± 8 | 23 ± 11 | 35 ± 12 | 58 ± 26 |
HRT = hydraulic retention time, NLR = nitrogen loading rate, DO = dissolved oxygen, ARR = ammonia removal rate, NRR = nitrogen removal rate. COD and nitrogen species are dissolved (filtered, 0.45 μm).