单项选择题
A.100% B.1/2 C.1/5 D.1/3
One of the reasons that cause oil flowed from sludge ou...
单项选择题One of the reasons that cause oil flowed from sludge outlet of a self-cleaning separator is（）
A.seal water supply be cut off B.make up water supply be cut off C.oil outlet valve closed or not open sufficiently D.the flow rate of oily water is too much
When two oil separators are working in series, they sho...
单项选择题When two oil separators are working in series, they should work with （）
A.both as clarifiers B.first one as clarifiers, second one as purifier C.both as purifiers D.first one as purifier, second one as clarifier
Concerning the management of sewage treatment plant usi...
单项选择题Concerning the management of sewage treatment plant using activated sludge, which of the following is correct?（）
A.the plant should be prohibited to supplying air B.the plant should work at intervals C.the plant should be added disinfector in time D.we should check strength of activated sludge, ivory-white color is best
