wastewater liquid residual

例句：

1. 1. The city's wastewater treatment plant is responsiblefor removing pollutants from the city's waterways.
   该市的污水处理厂负责从城市水道中去除污染物。
2. 2.The sewage system in this area isoutdated and needs to be upgraded toprevent contamination.
   该地区的污水处理系统过时了，需要升级以防止污染。
3. 3. Industrial wastewater contains harmful chemicalsthat need to be treated before it canbe released into the environment.
   工业废水含有有害化学物质，需要在排放到环境中之前进行处理。