经济有效地控制氨氮废水污染是当前面临的重大课题。

Economical and effective control of pollution by ammonia-nitrogen waste water is a vital problem currently.

youdao

经济有效地控制氨氮废水污染是当前面临的重大课题。

Economical and effective control of pollution by ammonia-nitrogen waste water is a vital problem currently.

youdao