英语听力文摘 English Digest 70、细菌可除臭?

　　Sewage stinks¹. But bacteria can make it smell better.
Oh, yeah?
That's true. 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 bleach³–not at all good for the environment.
And you are saying we could use other bacteria instead?
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 stink².
Using bacteria to break down the by-products of bacteria. Now that's clever.
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. But what do they give off?
Good question. And the answer is hydrogen sulfate–better known as sulfuric acid– almost odorless at the fairly low concentrations produced.
sewage:(下水道里的)污物
hydrogen sulfide:氢化硫
malodorous:难闻的
stink:臭味
by-product:副产品
payoff:结果,报偿
biofilter:细菌过滤器,生物过滤器
bleach:漂白剂
lye:碱液
sulfuric acid:硫磺酸
odorless:无味的

1 stinks   

v.散发出恶臭( stink的第三人称单数 )；发臭味；名声臭；糟透

参考例句：

• The whole scheme stinks to high heaven—don't get involved in it. 整件事十分卑鄙龌龊——可别陷了进去。 来自《简明英汉词典》
• The soup stinks of garlic. 这汤有大蒜气味。 来自《现代英汉综合大词典》

2 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。

3 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？