所以，Cohen解释道，轮船需要在一个港口把海水泵进巨大的压舱水柜，然后在下一个港口再泵出去。

So, Cohen explains, ships fill massive onboard ballast tanks by pumping seawater in at one port and pumping it out at the next.

youdao

海运船舶的活动也会对于环境造成有害的污染，包括船上废水处理、船底排水泵、油罐清洗、压舱、发电机和燃料等。

The activities of maritime vessels that can be environmentally harmful include ship waste disposal, bilge pumping, tank cleaning, ballasting, power generation, and fueling.

youdao