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單項(xiàng)選擇題

When anaerobic bacteria convert the sewage to an inert sludge,（）

A.no oxygen is needed
B.oxygen is necessary
C.oxygen is given off
D.no gas is produced

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單項(xiàng)選擇題

Bacteria which live are said to be aerobic（）

A.in the presence of oxygen
B.without oxygen
C.in the presence of nutrition
D.without nutrition

單項(xiàng)選擇題

It is that reduce the BOD by converting the organic content of the sewage to a chemically and organically inert sludge（）

A.the bacteria
B.oxygen
C.oxidizing function
D.agitation function