HSK 3
Zhège chéngshì xīnjiàn le yī zuò wūshuǐ chǔlǐchǎng.
This city built a new sewage treatment plant.
HSK 3
Gōngyè wūshuǐ xūyào jīngguò chǔlǐ.
Industrial wastewater needs to be treated.
HSK 7-9
Wūshuǐ bùnéng zhíjiē pái rù héliú.
Sewage cannot be discharged directly into rivers.