Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 6th Semester (Sixth Semester) 2017-2018 NCE602 ECE602 Environmental Engineering II Question Paper
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B. TECH
(SEM VI) THEORY EXAMINATION 2017-18
ENVIRONMENTAL ENGINEERING - II
T ime: 3 Hours T 0tal Marks: 100
Note: Attempt all Sections. If require any missing data; then choose suitably.
SECTION A
1. Attempt all questions in brief. 2 x 10 = 20
a. What are the impacts of oxygen demanding waste on surface water bodies?
b. What is Theoretical Oxygen Demand (ThOD)?
c. What are the obj ectives of grit removal?
(1. What do you understand by back washing?
e. What is the significance of GLSS in UASB?
f. What is the role of acetogenic bacteria in anaerobic digestion?
g. Distinguish between unit operations and unit processes.
h. What is the significance of solids retention time in extended aeration process?
i. What is the role of algae in aerobic pond?
j. What are the major factors in?uencing settling of discrete particles?
SECTION B
2. Attempt any three of the following: 10 x 3 = 30
a. What is an indicator organism? Discuss the characteristics of the ideal pathogen
indicator and indicate which organisms most nearly exhibit these
characteristics.
b. Why are coagulants used in the sewage treatment? List various coagulants used
along with their effectiveness in sedimentation of sewage.
c. (i) Discuss advantage and disadvantage of soda lime process and ion exchange
methods of water softening.
(ii). What is adsorption? Explain term ?activated? associated with Activated
Carbon.
(1. Design a conventional grit chamber unit for a design sewage ?ow of 120ML/d.
Assume suitable-data wherever necessary. Draw a schematic diagram of the
unit.
e. Design a septic tank with neat sketch for a hostel having 175 students. Design
sewage ?ow is 70 chd. Desludging period is one year. What would be the size
of the dispersion trench, if the ef?uent from the septic tank is to be discharged
in it?
SECTION C
3. Attempt any one part of the following: 10 x 1 = 10
(a) (i.) What is carbonaceous BOD? How the probable interference of Nitrogenous
oxygen demand is inhibited during BOD measurement?
(ii). Change in concentration of organic matter L, with time t, is given by dL/dt
= ?KL. Calculate the organic matter remaining after 4 days if the initial
concentration was 300 mg/l and K = 0.3 per day.
(b) Enumerate and explain the physico-chemical characteristics of waste water.
4. Attempt any one part of the following: 10 x 1 = 10
(a)
(13)
Design a plain sedimentation tank for an average ?ow of water 250 m3/hr. The
minimum size of particle to be removed 0.02 mm and expected performance of
tank may be taken as ?good?. Kinematic Viscosity of water at 200 C = 1.01 X 10'
6 m2/s and specific gravity of particle = 2.65.
Design a clari?occulator for an average ?ow of water 250 m3/hr. Assume any
data suitably if required.
5. Attempt any one part of the following: 10 x 1 = 10
(a)
(13)
Design a rapid sand filter for producing a net filtered water ?ow of 300 m3/hr.
The other relevant data are as follows :
Quantity of backwash water used = 4% of filter output
Time lost during backwashing = 30 min
Design rate of filtration = 5 m3/m2/hr
Length to width ratio = (1.25 to 1.33): 1
Under drainage system = Central manifold
Size of perforations = 9 mm.
A rapid sand filter has a bed depth of 0.7 m. It is composed of sand grains that
have a specific gravity of 2.65 and shape factor of 0.82. The porosity of the bed
is 0.45 throughout' The sieve analysis of the sand is shown below :
Sieve N0. Mass retained (%) Average
particle
size(mm)
0.87 1.0
8.63 0.71
21.30 0.54
28.10 0.46
23.64 0.38
7.09 0.32
3.19 0.27
2.16 0.23
9 1.02 0,18
Determine the head loss through the bed if the ?ow rate is 5.0 m/s and water
temperature is 17?C.
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6. Attempt any one part of the following: 10 x 1 = 10
(a)
(b)
The thickened sludge of 100 m3/d is processed in a standard rate anaerobic
digester. The moisture content of thickened sludge is 95%. The digestion
period is 25 days and the sludge must be stored for 3 months between final
disposal events during monsoon period. Organic content of the sludge is 70
percent and 60 percent of the organics are converted into gaseous and liquid
end products The solid content of the digested sludge is 4.5%. Determine the
required reactor volume. Assuming 100 kg/mz/yr solids loading rate, design the
number of sludge drying beds required for dewatering operation.
Brie?y describe the classification of trickling filters. Explain the mechanism of
biofilm formation and mass transfer in a tricking filter process with a neat
sketch.
7. Attempt any one part of the following: 10 x 1 = 10
(a) Write short notes on duckweed pond, vermiculture and root zone technologies.
(b) What is sludge digestion? What are two basic types of sludge digestion units?
Also name and describe methods of sludge disposal.
This post was last modified on 29 January 2020