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GATE CE 2023 Set 2
MCQ (More than One Correct Answer)
+2
-0
In the context of water and wastewater treatments, the correct statements are:
A
particulate matter may shield microorganisms during disinfection
B
ammonia decreases chlorine demand
C
phosphorous stimulates algal and aquatic growth
D
calcium and magnesium increase hardness and total dissolved solids
2
GATE CE 2023 Set 2
MCQ (More than One Correct Answer)
+2
-0
Which of the following statements is/are TRUE for the aerobic composting of sewage sludge?
A
Bulking agent is added during the composting process to reduce the porosity of the solid mixture
B
Leachate can be generated during composting
C
Actinomycetes are involved in the process
D
In-vessel composting systems cannot be operated in the plug-flow mode
3
GATE CE 2023 Set 2
Numerical
+2
-0

The theoretical aerobic oxidation of biomass (C5H7O2N) is given below:

C5H7O2N + 5O2 โ†’ 5CO2 + NH3 + 2H2O

The biochemical oxidation of biomass is assumed as a first-order reaction with a rate constant of 0.23/d at 20ยบC (logarithm to base e). Neglecting the second-stage oxygen demand from its biochemical oxidation, the ratio of BOD5 at 20ยบC to total organic carbon (TOC) of biomass is _______ (round off to two decimal places).

[Consider the atomic weights of C, H, O and N as 12 g/mol, 1 g/mol, 16 g/mol and 14 g/mol, respectively

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4
GATE CE 2023 Set 2
Numerical
+2
-0

A system of seven river segments is shown in the schematic diagram. The Riโ€™s, Qiโ€™s, and Ciโ€™s (i = 1 to 7) are the river segments, their corresponding flow rates, and concentrations of a conservative pollutant, respectively. Assume complete mixing at the intersections, no additional water loss or gain in the system, and steady state condition. Given: Q1 = 5 m3/s ; Q2 = 15 m3/s ; Q4 = 3 m3/s ; Q6 = 8 m3/s ; C1 = 8 kg/m3; C2 = 12 kg/m3; C6 = 10 kg/m3. What is the steady state concentration (in kg/m3, rounded off to two decimal place) of the pollutant in the river segment 7 ? ______

GATE CE 2023 Set 2 Environmental Engineering - Disposal of Sewage Effluent Question 1 English
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