85.

86.

87.

88.

89.

90.

91.

92.

93.

Tron and manganese can be removed from water by :
(^) Boiling (B) Chlorination
(C) Activated carbon (D) Aeration followed by coagulation

Chlorine demand of water is :

(^) Applied chlorine (0) Residual chlorine
൭ ൧-൪) ட) இடு
Which of the following is not a coagulant?
(A) Potassium permanganate (B) Alum
(C)_ Ferric chloride (D)_ Ferric sulphate
The efficiency of sedimentation tank does not depend upon :
(A) Detention time (B) Depth of the tank
(C) Length of the tank (D) Horizontal velocity of water

The suitable layout for a water supply distribution system, for an irregularly grown town is:
(A) Dead end system (B) Grid iron system
(C) Ring system (D) Radial system

In population forecasting, compared to the geometrical increase method, the arithmetical
increase method gives :

(^) Higher value ൯) Lesser value
(C) Equal value (D) May vary

Pickup the incorrect statement :
(A) Sewer pipes carry sewage flow by gravity
(B) Sewer pipe material has to withstand wear and tear due to abrasion

(C) Sewer pipes should be designed for a self-cleansing velocity of atleast 0.45 m/sec
at minimum discharge or 0.8 m/sec at full discharge

(D) Sewer pipes can be carried up and down the hills and valleys

The specific gravity of sewage is:
(A) Zero (B) Slightly less than 1
(C) Slightly greater than 1 (D) Equal tol

If the depletion of oxygen is found to be 2 mg/l after incubating 3 ml of sewage diluted to
300 ml, at 20°C for 5 days, then the BODs of the sewage would be :

(A) 200 mg/l (B) 300 mg/l
(C) 600 mg/l (D) None of these

17 121/2022
[P.T.0.]