A.Oil temperature too high
B.Diameter of gravity disc too large
C.Oil temperature too low
D.High level tank out of water

A.Oil inlet valve opening too quickly
B.Oil temperature too high
C.Diameter of gravity disc too small
D.Viscosity of oil too low

A.cut off the power
B.cut off the oil inlet
C.open guide water valve
D.close oil outlet value

A.acid
B.sludge
C.mechanical impurity
D.salinity

A.too little seal water
B.improper gravity disc
C.oil discharging pump not working very well
D.low water level of the working water

A.100%
B.80%
C.1/2
D.1/3

A.100%
B.1/2
C.1/5
D.1/3

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

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

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

A.chlorine water
B.ozone
C.hypo-calcium chloride
D.calcium oxide