Related Questions

The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is
A 1
B 100
C Infinite
D Zero
The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by
A TOD > BOD > COD
B TOD > COD > BOD
C BOD > COD > TOD
D COD > BOD > TOD
The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is
A 1 ppm
B 4 ppm
C 10 ppm
D 40 ppm
The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of
A 1 mg/liter
B 10 mg/liter
C 100 mg/liter
D 1000 mg/liter
Dissolved oxygen content in river water is around __________ ppm.
A 5
B 100
C 250
D 500
For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed
A 3 ppm
B 4 ppm
C 5 ppm
D 10 ppm
In order to protect the aquatic creatures, the dissolved oxygen content in fresh water stream should never be less than __________ PPm.
A 0.5
B 1
C 5
D 20
Use of water having dissolved oxygen in boilers promotes
A Corrosion
B Sequestration
C Scale formation
D None of these
Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by
A Natural aeration of water stream
B Photosynthetic action of algae
C Both A & B
D Neither A nor B
For existence of aquatic life in water, the dissolved oxygen content in it, should not be less than __________ ppm.
A 10000
B 5
C 500
D 1000

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