| English | eng-000 |
| secondary treatment | |
| العربية | arb-000 | معالجة ثانوية |
| čeština | ces-000 | sekundární čištění |
| 普通话 | cmn-000 | 二次处理 |
| 普通话 | cmn-000 | 二级处理 |
| Deutsch | deu-000 | Nachbehandlung von Abwässern |
| English | eng-000 | aftertreatment |
| English | eng-000 | double treating |
| English | eng-000 | secondary biological treatment |
| français | fra-000 | traitement biologique secondaire |
| français | fra-000 | traitement secondaire |
| íslenska | isl-000 | tveggja þrepa hreinsun |
| русский | rus-000 | вторичная биологическая очистка |
| русский | rus-000 | вторичная обработка |
| español | spa-000 | tratamiento biológico secundario |
| español | spa-000 | tratamiento secundario |