【英语时差8,16】细菌让污水不臭

Certain forms of bacteria feasting on sewage give off hydrogen sulfide, a really malodorous chemical, and one of several that give sewage its “pleasing” smell. In general this problem has been treated with powerful chemicals like bleach¹–not at all good for the environment. That's what Marc Deshusses, of University of California Riverside, argues and his technique is catching² on. There’s already a sewage treatment plant in California that’s using bacteria that degrade hydrogen sulfide, using the oxygen in air, to get rid of the stink³. Nor is the payoff only environmental. Using “biofilters,” as this kind of system is called, means plant operators can decrease the amount of dangerous chemicals onsite. Biofiltering is also cheaper than chemically treating the problem with bleach or lye. Some bacteria break down sewage. They give off hydrogen sulfide. Other bacteria break down hydrogen sulfide.Hydrogen sulfate–better known as sulfuric acid– almost odorless at the fairly low concentrations produced.

1 bleach   

vt.使漂白；vi.变白；n.漂白剂

参考例句：

• These products don't bleach the hair.这些产品不会使头发变白。
• Did you bleach this tablecloth?你把这块桌布漂白了吗？

2 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。

3 stink   

vi.发出恶臭；糟透，招人厌恶；n.恶臭

参考例句：

• The stink of the rotten fish turned my stomach.腐烂的鱼臭味使我恶心。
• The room has awful stink.那个房间散发着难闻的臭气。