Correct
三废
/ sānfèi /
Strokes
Definition
three types of waste product, namely: waste water 废水[fèi shuǐ], exhaust gas 废气[fèi qì], industrial slag 废渣[fèi zhā]
Example
As a Noun
three wastes ［i.e. waste gas, water, and industrial residue］ in industrial production
1
Biàn
变
sānfèi
三废
wéi
为
sānbǎo
三宝
make the three wastes into three treasures
2
Zhìlǐ
治理
sānfèi
三废
bring under control the three wastes
3
Huíshōu
回收
sān
三
fèi
废
recycle the three wastes