净化污水的英文：
purify sewage water

purify是什么意思：
v. 使纯净，净化；使纯洁；精炼；使纯正

To cleanse or purify or become cleansed or purified.
（使）清洁，（使）净化

purify or refine,esp by repeated distillation
净化或精炼;（尤指）分馏,精馏

To increase the concentration of, separate, or purify by or as if by distillation.
精炼用蒸馏法或好象用蒸馏法增加浓度、分离或净化

sewage是什么意思：
n. 脏水，污水，污物；下水道

The sewage channel chokes.
这条污水道塞住了。

defile a river with sewage.
用污水弄脏河流

The air is thick with the stench of sewage.
这里的空气里弥漫着脏水的恶臭味。

water是什么意思：
n. 水；雨水；海水；海域
v. 给…浇水；供以水；加水；流泪；流口水

In smooth water
进入顺境

Is the water on or off?
自来水龙头开着还是关着？

Water Skiing is a surface water sport.
滑水是一项水面运动。