77.

78.

79.

80.

81.

82.

83.

84.

85.

110/23

A sewer of 4m diameter, laid at a gradient of 1 in 400 runs full. Using Manning’s
formula, the velocity of flow is (Take Manning’s coefficient as 0.01)

A) 1.25 m/s B) 2.5 m/s
C) 5.0 m/s D) 10.0 m/s

The Permissible limit of Iron (in mg/L) (in the absence of alternate source) as per
IS : 10500;2012 including the latest amendments is

A) 0.1 B) 0.3 C) 0.5 D) 1.0
The first watering before sowing the crop in a field is called

A) Capacity factor B) Cumec day

C) Kor watering D) Paleo

5 mL of sewage was diluted and a standard BOD test was performed. The initial
Dissolved Oxygen (DO) and the final DO of the tested sample were 8.2 mg/L and
6.2 mg/L respectively. Then the Biochemical Oxygen Demand of the tested sample is

A) 2mg/L B) 20 mg/L C) 12 mg/L D) 120 mg/L

50 million litres of sewage per day is flowing into the aeration tank of an activated
sludge processing unit having volume of 10,000 m. Then the aeration period to be
maintained in the aeration tank in hours is

A) 4 B) 5 ೦06 D) 7

The maximum discharge in a circular sewer is obtained when
A) the sewer is running full

B) the depth of flow is 0.81 times full depth

C) the depth of flow is 0.90 times full depth

D) the depth of flow is 0.95 times full depth

What is the theoretical oxygen demand of 300 mg/L glucose solution ?

A) 300 mg/L B) 320 mg/L C) 340 mg/L D) 360 mg/L
Symon’s rain gauge is a

A) Tipping bucket gauge B) Weighing type gauge

C) Float recording type gauge D) Non recording gauge

The ratio of the mean supply (discharge) to the full supply (discharge) of a canal is
A) Time factor B) Capacity factor

C) Kennedy factor D) Lacey’s factor

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