There was some sludge at the bottom of the tank.

油箱底有油泥。

《牛津词典》

Next up is the primary sedimentation tank, where sludge settles to the bottom and lighter liquids like grease, oil and soap rise to the top.

下一步就是一级沉淀池，污泥沉淀到底部，轻质液体例如油脂、油和皂类浮到上面。

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Result: When sludge forms at the bottom of the carton, you toss it-and a whole lot of good-for-you calcium goes down the drain.

结果：盒子底部形成了大量的深沉物，你就把它扔了——一大堆对你有益的钙也进了下水道。

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Sludge settles to the bottom, leaving clean water on top.

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However, a group of six divers inspected the bottom of the lake on Saturday and discovered no fragments amid the sludge.

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Under the plate rack on the draining board and at the bottom of the plastic pot for the cutlery was a murky gray sludge.

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