单项选择题
A.no oxygen is needed B.oxygen is necessary C.oxygen is given off D.no gas is produced
Bacteria which live are said to be aerobic（）A.in the pr...
单项选择题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
It is that reduce the BOD by converting the organic con...
单项选择题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
The basic process of biological sewage treatment consis...
单项选择题The basic process of biological sewage treatment consists of the liquor either by bubbling air through it or by agitating the surface（）
A.oxygenating B.oxidizing C.deoxygenating D.proportioning
