| Value | Category | Cases | |
|---|---|---|---|
| . | 69205 |
90%
|
|
| 1 | Boiling | 2654 |
3.5%
|
| 2 | Adding chemical | 2415 |
3.1%
|
| 3 | Filtering | 1686 |
2.2%
|
| 4 | Sedimentation | 916 |
1.2%
|
| 5 | Other | 35 |
0%
|
| ? | 151 |