nightsoil sludge

例句：

1. 1. The sewage treatment plant has been struggling with the nightsoil sludge problem.
   污水处理厂一直在努力解决污泥问题。
2. 2.The farmers used to collect nightsoil for fertilizer, but now they prefer to use chemical fertilizers.
   过去农民们会收集污泥作为肥料，但现在他们更喜欢使用化学肥料。
3. 3.The sludge from the wastewater treatment plant is a major concern for environmentalists.
   污水处理厂产生的污泥是环保人士的主要关切。