If you are replacing the bottom element, remove the accumulatedsediment on the bottom of the tank.
如果是拆卸下部加热元件，需要清除累积在内胆底部的沉淀物。
2
In the eutrophication process of Wuli lake, large amount of nitrogen, phosphorous and organic matter accumulated in the sediment of the lake bottom.
在五里湖富营养化过程中，氮、磷及有机物质在湖底沉积物中大量积累。
3
It is found that the relationships between the accumulated volumes of sediment deposition in the reservoir and the average pool levels follow the earlier trend curves very well.