1
GATE CE 2025 Set 1
MCQ (Single Correct Answer)
+1
-0.33

Fecal Coliform (FC) concentration in river water was measured as 10780 cfu/100 ml. The FC concentration after the conventional water treatment, but before chlorination, was measured as $23 \mathrm{cfu} / 100 \mathrm{ml}$. The 'Log Kill' (inactivation) of FC due to the conventional water treatment is closest to

A
4.00
B
2.50
C
2.67
D
3.00
2
GATE CE 2025 Set 1
MCQ (More than One Correct Answer)
+1
-0
The Surface Overflow Rate (SOR) in a rectangular sedimentation tank is $45 \mathrm{~m}^3 / \mathrm{m}^2 / \mathrm{d}$. Minimum diameters of spherical inorganic and organic particles expected to be completely removed in this tank are calculated. Assume that Stoke's law is applicable. Which of the following options is/are correct: Specific gravity of inorganic particles $=2.65$ Specific gravity of organic particles $=1.20$ Acceleration due to gravity $(\mathrm{g})=9.81 \mathrm{~m} / \mathrm{s}^2$ Kinematic viscosity $(v)=1 \times 10^{-6} \mathrm{~m}^2 / \mathrm{s}$
A
Minimum diameter of inorganic particles is $24 \mu \mathrm{~m}$
B
Minimum diameter of organic particles is $69 \mu \mathrm{~m}$
C
Minimum diameter of inorganic particles is $15 \mu \mathrm{~m}$
D
Minimum diameter of organic particles is $55 \mu \mathrm{~m}$
3
GATE CE 2025 Set 1
MCQ (More than One Correct Answer)
+1
-0
Aeration is employed as a treatment option for the removal of several pollutants from contaminated water. Identify the pollutant(s), where aeration is employed as a part of their removal:
A
Iron
B
Cadmium
C
Manganese
D
Zinc
4
GATE CE 2023 Set 2
MCQ (More than One Correct Answer)
+1
-0
Which of the following is/are NOT active disinfectant(s) in water treatment?
A
OH (hydroxyl radical)
B
O3 (ozone)
C
OCl (hypochlorite ion)
D
Cl (chloride ion)
GATE CE Subjects
EXAM MAP