Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Winter 7th Sem 2171306 Wastewater Engineering Previous Question Paper
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER?VII (NEW) EXAMINATION ? WINTER 2020
Subject Code:2171306 Date:30/01/2021
Subject Name: Wastewater Engineering
Time:10:30 AM TO 12:30 PM Total Marks: 47
Instructions:
1. Attempt any THREE questions from Q.1 to Q.6.
2. Q7 is compulsory.
3. Make suitable assumptions wherever necessary.
4. Figures to the right indicate full marks.
MARKS
Q.1 (a) Differentiate between domestic wastewater and industrial wastewater.
03
(b) Design an aerated grit chamber for the treatment of Municipal waste water. The average
04
flow rate is 0.60 m3/s and the peaking factor is 2.25.
(c) Design a bar rack (mechanically cleaned) for an average flow 40 MLD flow condition
07
in incoming sewer is given by:
a. Diameter of sewer = 1.53 m
b. Depth of flow at peak flow =1 m
c. Velocity at peak design flow = 0.8m/s
d. Drop to screen chamber flow with respect to sewer invert is 0.08
e. Peaking Factor = 2
Q.2 (a) Explain the concept of flocculation and the different types of flocculators.
03
(b) Design an oil and grease trap to remove 180 mg/L of oil and grease from a flow of 43000
04
m3/day of wastewater.
(c) For the flow rate data given in the table below, find out the volume of equalization tank.
07
Time
1
2
3
4
5
6
7
8
9
10
11
12
Q, m3/h
90 116 225 231 249 310 640 750 830 825 720 700
Time
13
14
15
16
17
18
19
20
21
22
23
24
Q, m3/h 650 570 450 320 230 225 210 194 165 135 105 60
Q.3 (a) Enlist various methane precursors in anaerobic decomposition.
03
(b) Explain volumetric organic loading, upflow velocity and gas collection system.
04
(c) Explain the UASB process with its design criteria.
07
Q.4 (a) What is Bio tower? Explain its working.
03
(b) Explain the purpose of following unit operations/processes in a wastewater treatment
04
plant: (i) Grit Chamber, (ii) Attached growth biological process (iii) Secondary
Sedimentation and (iv) Nitrification
(c) Design a rotating biological contactor to treat a flow of 50 MLD flow of primary treated
07
wastewater having BOD5 of 200 mg/L. Desired effluent BOD5 is 30 mg/L.
Q.5 (a) Explain the factors responsible for foaming in ASP.
03
(b) Enlist and Explain the operational problems of chemical unit operations.
04
(c) Explain the phases of SBR operational cycle with neat sketch.
07
Q.6 (a) Write a short note on rotating biological contactors.
03
(b) Differentiate between standard rate and high rate anaerobic digesters.
04
1
(c) If 1 MLD flow of domestic wastewater with settled BOD5 of 250 mg/L is treated in the
07
conventional activated sludge plant at 0.3 F/M ratio to obtain 85% BOD removal
efficiency, estimate the net surplus sludge produced per day. Assume suitable reaction
constants.
Q.7 (a) Differentiate between extended aeration and tapered aeration.
05
OR
Q.7 (a) Explain various methods of thickening of sludge.
05
**************
2
This post was last modified on 04 March 2021