Related Questions

Aerobic biological oxidation ponds used for the purification of polluted water
A Destroys/removes pathogen from the sewage
B Is not very effective for nonbiodegradable substances (e.g. ABS) containing effluents
C Destroys/removes pathogen much more effectively if the sewage is chlorinated
D All of the above
Biological oxidation ponds remove organic matters present in the polluted water by
A Using the activities of bacteria and other micro organisms
B Aerobic oxidation
C Both A & B
D Neither A nor B
A. some towns in Bangladesh are polluted B. All polluted towns should be destroyed C. Town Dhaka should be destroyed D. Town Dhaka is polluted E. Some towns in Bangladesh should be destroyed
A BDE
B BAE
C ADE
D CDB
Each question consists of five statements following by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements. A.Some towns in Bangladesh are polluted .B.All polluted towns should be destroyed.C.Town Dhaka should be destroyed.D.Town Dhaka is polluted.E.Some towns in Bangladesh should be destroyed
A BDE
B BAE
C ADE
D CDB
The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known
A Bio-Chemical Oxygen Demand (B.O.D.)
B Dissolved Oxygen (D.O.)
C Chemical Oxygen Demand (C.O.D.)
D None of these
The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated.
A Decreases
B Increases
C Remains constant
D May increase or decrease ; depends on the chemical characteristics of polluted water
Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes
A Foaming
B Odour nuisances
C Undesirable plant growth
D Turbidity
Coal mines drainage waste water (acidic in nature) results from the earth's water percolating through the voids created in coal bed during mining. This polluted water which either drains out naturally to water courses or are removed before starting the mining is
A Neutralised by alkali treatment
B Left as such without any treatment
C Diluted with fresh water to reduce its acidity
D None of these
The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria.
A Anaerobic
B Saphrophytic
C Aerobic
D Parasitic
Presence of non-biodegradable substances, like alkyl benzene sulphonate (ABS) from the detergents in polluted water stream causes
A Fire hazards
B Explosion hazards
C Persistent foam
D Depletion of dissolved oxygen

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