൫2.

83.

84.

3

57.

58.

A reservoir which retains excess supplies during periods of peak flows and release them
gradually during low flows :

(^) Retarding reservoir (B) Flood control reservoir

(C) Distribution reservoir (D) Conservation reservoir

A plot of cumulative rain versus time is called :
(ക) Mass curve ര) Hydrograph
(¢) Hyetograph (D) DAD curve

Example of subsurface source of water 5
(A) दिश्या (B) Ponds
(C) Spring (D) Streams

The standard unit of turbidity of water is that which is produced by 1 mg of
dissolved in one litre of distilled water.

(4) Finely divided silica - (B) Platinum cobalt

(C) Potassium permanganate (D) Formazin

A compound that imparts temporary hardness to water :
(ಗ) Calcium sulphate (©) Magnesium chloride

(C) Calcium nitrate (D) Magnesium carbonate

Which of the following is incorrect regarding a slow sand filter :
(ಹ) Tncoming water should not be treated by coagulants
(B) Depth of water should be double the depth of filter sand
(C) Loss of head is limited to a maximum of 1.2 m

(D) Cleaning should not be done by back washing

A method of disinfection of drinking water :
(5) Treatment with excess lime (B) Treatment with ozone
(C) Electra-Katadyn process (D) All the above

BOD of effluent from secondary biological treatment of sewage is :
(^) 010 5% of the original (B) 5 to 10% of the original
(C) 25 to 40% of the original (D) 50 to 60% of the original

9 143/2015
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