The ratio of oxygen available to the oxygen required for stabilization of sewage is called
A.biochemical oxygen demand
B.relative stability
C.bacterial-stability factor
D.oxygen-ion concentration
Category: Chemical Environmental Engineering Mcqs
Chloramines are used in water treatment
A.for disinfection
B.for taste and colour control
C.as algicides
D.for weed control in reservoirs
In an aerosol
A.some of the particles may be positively charged
B.some of the particles may be negatively charged
C.some of the particles may be uncharged
D.all of the above
The gas from sludge digestion tanks is mainly composed of
A.nitrogen
B.hydrogen sulphide
C.methane
D.carbon monoxide
Septic tanks are primarily used for
A.the aerobic decomposition of deposited sweage solids
B.separation of deposited solids
C.anaerobic decomposition of deposited solids
D.separation of oil and grease scums.
For a given particle size the collection efficiency of a cyclone separator
A.will be increased at higher pressure drops
B.will be decreased at higher pressure drops
C.will not be affected by changing pressure drop
D.none of the above
Which of the following devices of particulate collection is the least efficient?
A.Cyclone separator
B.Electrostatic precipitator
C.Fabric filter
D.Wet scrubber
The process of lagooning is primarily a means of
A.increasing the capacity of storage reservoirs
B.increasing flow of sewage through Imhoff tanks
C.reducting the excessive flow in sewers
D.disposing sludge
The operation of electrostatic precipitator relies on
A.producing an electric charge on the particle to be collected and then directing it by electrostatic forces to the collecting electrodes
B.centrifugal force acting on the particle
C.diffusion of dust particles
D.the creation of intimate contact between a stream of gas and a flow of scrubbing liquor.
The resistance offered by filter used in a fabric filter
A.varies inversely as the particle size and directly as the dust concentration
B.varies inversely as the dust concentration and directly as the particle size
C.varies directly as the particle size as well as the dust concentration
D.varies inversely as the particle size as well as the dust concentration
