 |
| |||
| mechanical process (sewage treatment); primary treatment (sewage treatment); settling (sewage treatment) | |||
| mechanisches Verfahren: 2 phrases in 2 subjects |
| Earth sciences | 1 |
| Foreign trade | 1 |
|
| |||
| mechanical process (sewage treatment); primary treatment (sewage treatment); settling (sewage treatment) | |||
| mechanisches Verfahren: 2 phrases in 2 subjects |
| Earth sciences | 1 |
| Foreign trade | 1 |