1
GATE CE 2022 Set 1
MCQ (Single Correct Answer)
+1
-0.33

In a water sample, the concentrations of Ca2+, Mg2+ and HCO$$_3^ - $$ are 100 mg/L, 36 mg/L and 122 mg/L, respectively. The atomic masses of various elements are : Ca = 40, Mg = 24, H = 1, C = 12, O = 16. The total hardness and the temporary hardness in the water sample (in mg/L as CaCO3) will be

A
400 and 100, respectively.
B
400 and 300, respectively.
C
500 and 100, respectively.
D
800 and 200, respectively.
2
GATE CE 2022 Set 1
Numerical
+2
-0

A wastewater sample contains two nitrogen species, namely ammonia and nitrate. Consider the atomic weight of N, H, and O as 14 g/mol, 1 g/mol, and 16 g/mol, respectively. In this wastewater, the concentration of ammonia is 34 mg NH3/liter and that of nitrate is 6.2 mg NO$$_3^ - $$/liter. The total nitrogen concentration in this wastewater is _________ milligram nitrogen per liter.

(round off to one decimal place)

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3
GATE CE 2022 Set 1
Numerical
+2
-0

A 2% sewage sample (in distilled water) was incubated for 3 days at 27$$^\circ$$C temperature. After incubation, a dissolved oxygen depletion of 10 mg/L was recorded. The biochemical oxygen demand (BOD) rate constant at 27$$^\circ$$C was found to be 0.23 day$$-$$1 (at base e). The ultimate BOD (in mg/L) of the sewage will be ________. (round off to the nearest integer)

Your input ____
4
GATE CE 2022 Set 1
Numerical
+1
-0

A water treatment plant has a sedimentation basin of depth 3 m, width 5 m, and length 40 m. The water inflow rate is 500 m3/h. The removal fraction of particles having a settling velocity of 1.0 m/h is ________. (round off to one decimal place) (Consider the particle density as 2650 kg/m3 and liquid density as 991 kg/m3)

Your input ____
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