| Steel slag concentration (%) | Bacterial biomass (×108 cells/g) | pH | ||
| Week 0 | Week 4 | Week 0 | Week 4 | |
| 0 | 9.0 | 10.2 | 5.9 | 7.1 |
| 0.2 | 10.0 | 9.8 | 6.4 | 7.6 |
| 0.4 | 10.5 | 9.9 | 6.7 | 7.7 |
| 0.6 | 10.5 | 10.3 | 6.6 | 8.1 |
| 0.8 | 10.0 | 10.2 | 7.1 | 8.2 |
| 1.0 | 10.4 | 9.6 | 7.2 | 8.3 |
| 1.2 | 7.9 | 7.3 | 7.4 | 8.5 |
| 1.4 | 7.6 | 7.4 | 7.0 | 8.3 |