GATE CE area:environmental-engineering PYQs & Answers — Page 4

Questions 31–40 of 110. Imported answers require independent review unless marked reviewed.

A water treatment plant treats 25 MLD water with a natural alkalinity of 4.0 mg/L (as CaCO₃). It is estimated that, during coagulation of this water, 450 kg/day of calcium bicarbonate (Ca(HCO₃)₂) is required based on the alum dosage.

Consider the atomic weights as: Ca-40, H-1, C-12, O-16.

The quantity of pure quick lime, CaO (in kg) required for this process per day is__________ (rounded off to 2 decimal places).

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An organic waste is represented as C

(Atomic weights: S-32, H-1, C-12, O-16, N-14).

Assume complete conversion of S to SO

while burning.

generated (in grams) per kg of this waste is __________ (rounded off to 1 decimal place).

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Which one of the following statements is TRUE for Greenhouse Gas (GHG) in the atmosphere?

Your answerChoose one option.

GHG absorbs the incoming short wavelength solar radiation to the earth surface, and allows the long wavelength radiation coming from the earth surface to pass through

GHG allows the incoming long wavelength solar radiation to pass through to the earth surface, and absorbs the short wavelength radiation coming from the earth surface

GHG allows the incoming long wavelength solar radiation to pass through to the earth surface, and allows the short wavelength radiation coming from the earth surface to pass through

GHG allows the incoming short wavelength solar radiation to pass through to the earth surface, and absorbs the long wavelength radiation coming from the earth surface

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Identify the waterborne diseases caused by viral pathogens:

Your answerSelect all correct options. You can choose more than one.

Acute anterior poliomelitis

Cholera

Infectious hepatitis

Typhoid fever

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Which of the following is/are NOT active disinfectant(s) in water treatment?

Your answerSelect all correct options. You can choose more than one.

•OH (hydroxyl radical)

O₃ (ozone)

OCl⁻ (hypochlorite ion)

Cl⁻ (chloride ion)

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In the following table, identify the correct set of associations between the entries in Column-1 and Column-2.

Column-1	Column-2
P: Reverse Osmosis	I: Ponding
Q: Trickling Filter	II: Freundlich Isotherm
R: Coagulation	III: Concentration Polarization
S: Adsorption	IV: Charge Neutralization

Your answerChoose one option.

P-II, Q-I, S-III

Q-III, R-II, S-IV

P-IV, R-I, S-II

P-III, Q-I, R-IV

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Match the following air pollutants with the most appropriate adverse health effects:

Air pollutant	Health effect to human and/or test animal
(P) Aromatic hydrocarbons	(I) Reduce the capability of the blood to carry oxygen
(Q) Carbon monoxide	(II) Bronchitis and pulmonary emphysema
(R) Sulfur oxides	(III) Damage of chromosomes
(S) Ozone	(IV) Carcinogenic effect

Your answerChoose one option.

(P) – (II), (Q) – (I), (R) – (IV), (S) – (III)

(P) – (IV), (Q) – (I), (R) – (III), (S) – (II)

(P) – (II), (Q) – (I), (R) – (II), (S) – (IV)

(P) – (IV), (Q) – (I), (R) – (II), (S) – (III)

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In the context of water and wastewater treatments, the correct statements are:

Your answerSelect all correct options. You can choose more than one.

particulate matter may shield microorganisms during disinfection

ammonia decreases chlorine demand

phosphorus stimulates algal and aquatic growth

calcium and magnesium increase hardness and total dissolved solids

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Which of the following statements is/are TRUE in relation to the Maximum Mixing Depth (or Height) '

' in the atmosphere?

Your answerSelect all correct options. You can choose more than one.

is always equal to the height of the layer of unstable air

Ventilation coefficient depends on

A smaller

will have a smaller air pollution potential if other meteorological conditions remain same

Vertical dispersion of pollutants occurs up to

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A flocculator tank has a volume of 280 m³. The temperature of water in the tank is 15°C, and the average velocity gradient maintained in the tank is 100/s. The temperature of water is reduced to 5°C, but all other operating conditions including the power input are maintained as the same. The decrease in the average velocity gradient (in %) due to the reduction in water temperature is ______________ (round off to nearest integer).

[Consider dynamic viscosity of water at 15°C and 5°C as 1.139×10⁻³ N-s/m² and 1.518×10⁻³ N-s/m², respectively]

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GATE CE area:environmental-engineering PYQs

Question 61

Question 61

Question 20

Question 27

Question 29

Question 45

Question 45

Question 48

Question 50

Question 63