TEST ON ENVIRONMENTAL ENGINEERING
1. In a water treatment plant PH value of
6. The carbonate and non-carbonate hardness
incoming and outgoing water are 7.2 and 8.4.
of water having a total alkalinity of 200 m g/lit as
Assuming a linear variation of PH with time,
, 120 mg/lit of and 60 mg/lit of
determine the average PH of water.
A. 7.8
B. 8.0
C. 7.47 D. 8.17
2. The Threshold odour number for a water
ions.
What
is
the
Non-carbonate
hardness as ? A. 550 B. 200 C. 350 D. 300
sample of 40 ml is diluted to standard 200 ml
7. The concentration of ions in water
mixture in which odour is barely detectable to
sample is measured as 17 mg/lt at . What
the sense of smell is
is PH of water sample.
A. 5
B. 4
C. 6
D. 8
3. The product of and ions in a
stronger acid is
. Determine the resultant
PH value of one with PH=6 and PH =8. A. 6.3
B. 6.5
C. 7.0
D. 7.3
A. 3
B. 11
C. 12
D. 6
8. In water sample of PH = 9.25, the concentration of hydroxyl ions in mM/l is A. B. C. D. 4.75 9. Total suspended particulate matter TSP
4. The carbonate and non-carbonate hardness
concentration in an ambient air is to be
of water having a total alkalinity of 200 mg/lit as
measured using high volume sampler. The filter
, 120 mg/lit of and 60 mg/lit of ions. What is the total hardness
used for this purpose had an initial dry weight
as ?
and the initial air flow rate through filter was
A. 550 B. 200 C. 350 D. 300
of 9.787 gm. The filter was mounted in sampler set at 1.5 . Sampling continued for 24 hours. The air flow after 24 hours was
5. The carbonate and non-carbonate hardness
measured to be 1.4 . The dry weight of
of water having a total alkalinity of 200 mg/lit as
filter paper after 24 hours sampling was 10. 283
, 120 mg/lit of and 60 mg/lit of ions. What is the carbonate hardness
gm. Assume a linear decline in air flow rate
as ?
concentration in ambient air.
A. 550 B. 200 C. 350 D. 300
A. 592
during sampling, what is the average TSP
B. 118.6
C. 237.5 D. 574.4
10. Ion concentration for ground water sample
15. A settling tank in a water treatment plant is
( PH = 8.1) are given below
designed for a surface overflow rate of 30
Ion
Conc. 100
6
15
250
45
39
per day. G=2.65, = 1000 ,
. Find the diameter of the particles in cm.
Find the total hardness and carbonate hardness
A. 0.002 B. 0.001 C. 0.003 D. 0.004
present in water sample (mg/l as )
16. For given discharge ,
A. 275, 275 B. 205, 205
detention period of 6 hours and velocity of flow
C. 250, 250 D. 308,
of 20 cm/min, what is the volume (cum) and
289
length ( L )of the tank required. 11. Waste water sample contains Mole/l of
milli
ion. What is the value of PH of
A. 3000, 72 B. 1500, 36 C. 1000, 12 D. 500, 6
the sample.
17. For given discharge ,
A. 8.6 B. 8.4 C. 5.6 D. 5.4
breadth 6 m, length 15 m, depth 3m find the detention time ( hours) and velocity (cm/min)
12. [
]
= 56 mg/l, [
]
= 30 mg/l,
[
]
= 190 mg/l, [ = 40 mg/l, [ ] = 3 mg/l and [ ] = 165 mg/l and PH of water is 7. Find the total hardness, carbonate hardness and
A. 3.0, 6.0 B. 3.24, 7.72 C. 4.5, 8.0 D. 5.0, 9.0 18. If 60 ppm suspended solids are present in water and 70 % of particles are removed in
non-carbonate hardness.
basin, G=2 and discharge
A. 225, 225, 0
then what is the mass of the dry sludge
B. 484, 225, 259
produced (Kg) C. 450, 150, 300 D. 242, 86, 156 A. 148 B. 158 C. 168 D. 178 13. What is the settling velocity in cm/sec of particle of diameter 0.005 cm, specific gravity 2.65
and
kinematic
viscosity
19. For given discharge , breadth 6 m, length 15 m, depth 3m find the
overflow rate lit/hr/sqm
A. 0.22 B. 2.2 C. 22 D. 0.022
A. 926 B. 864 C. 420 D. 320
14. A horizontal flow primary clarifier treats
20. A town has an existing horizontal flow with
waste water in which 10 %, 60 % and 30 % of
an overflow rate of 17 and it is
particles have settling velocities of 0.1 mm/sec,
describe to remove particles that have settling
0.2 mm/sec and 1 mm/sec respectively. What
velocity of 0.1 mm/sec. Assuming the tank is an
would be the total % of particles removed if
ideal sedimentation tank, the % of particles
clarifier operates at a surface over flow rate of
removal is approximately equal to
43.2 per day. A. 46 B. 56 C. 86 D. 100
A. 30 B. 50 C. 70 D. 90 21. For a flow of 5.7 MLD and detention time of 2 hours. The surface area (sqm) of a rectangular
sedimentation tank to remove all particles
27. A water treatment plant is required to
having settling velocity of 0.33 mm/sec is
process 28800 of raw water. ( density = 1000 and kinematic viscosity =
A. 20 B. 100 C. 200 D. 400 22. For a discharge of , alum
) The rapid mixing tank imparts a velocity gradient of 900 /sec to blend 35 mg/lit
dose of 12 ppm what is the release in Kg.
of alum with the flow for detention time of 2
A. 62 B. 42 C. 50 D. 80
mixing is
23. For a discharge of , alum
A. 32400 B. 64800 C. 16200 D. 8100
minutes. The power in watts required for rapid
dose of 12 ppm what is the alum requirement in Kg.
28. A circular primary clarifier processes an
A. 156 B. 186 C. 250 D. 180
water. The over flow rate is 35 The
average flow of 5005 of municipal waste
24. A coagulation tank clarifies 40 M lit of water every day. The quantity of filter Alum required
diameter of the clarifier shall be A. 13.5 B. 18.5 C. 23.5 D. 28.5
at the plant is 18 gm/lit. If the raw water is having an alkalinity requirement equivalent to 5
29. The following data are given for channel
mg/lit of , determine the quantity of
type grit chamber of length 7.2m. Flow through
filter alum and quick lime ( Containing 85 % of
velocity is 0.3 m/sec. Depth of waste water at
CaO) required per year by the plant in Kg/day
peak flow in channel is 0.9 m. Specific gravity of inorganic
A. 720, 82 B. 620, 42 C. 420, 32, D. 320, 92 25. A coagulation treatment plant with a flow of 0.5
is dosing alum at 23 mg/lit. No
other chemical are being added. The raw water suspended solids concentration is 37 mg/lit. The
particles
is
2.5,
viscosity
=
and density of water is 1000 . Assume the stokes law is valid. The largest diameter of particle (mm) that would be removed with 100 % efficiency is A. 5.77 B. 6.77 C. 7.77 D. 8.77
effluent suspended solids concentration is measured as 12 mg/lit. The sludge content is 1
30. A town is required to treat 4.2 /min of
% and specific gravity of solids is 3.01. What
raw
volume ( ) of sludge must be disposed
Flocculating particles are to be produced by
off each day.
chemical
water
for
daily
coagulation.
domestic A
column
supply. analysis
indicated that an overflow rate of 0.2 mm/s will A. 130.92
B. 120.12
C. 140.72
D. 150.62
26. 8 mg of copperas is consumed with lime at coagulation basin per litre of water. Determine the quantity of lime and copperas required in kg
produce satisfactory particle removal in a settling basin at a depth of 3.5 m. The required surface area (in ) for settling is (A) 210 (B) 350 (C) 1728 (D) 21000
to treat 10 MLD of water. 31. A settling tank in a water treatment plant is A. 80, 16.23 B. 40, 14 C. 20, 8 D. 10, 6
designed for a surface overflow rate of 30 .
Assume
specific
gravity
of
sediment particles = 2.65, density of water (ρ) = 1000 ,
dynamic
viscosity
of
Bicarbonate ( )
water
(µ)=0.001 N.s/ , and Stokes’ law is valid. The
Calcium (
approximate minimum size of particles in mm
Magnesium ())
that would be completely removed is: (A) 0.01 (B) 0.02 (C) 0.03 (D) 0.04 32. A water treatment plant is designed to treat 1 /s of raw water. It has 14 sand filters.
30
)
12 18
PH 8.5 a. Total hardness in mg/L as is (A) 1500 (B) 2000 (C) 3000 (D) 5000
Surface area of each filter is 50 . What is the loading rate (in ) with two filters out
of
service
for
routine
backwashing?
b. Alkalinity present in the water in mg/L as CaCO3 is
__________
(A) 250 (B) 1500 (C) 1750 (D) 5000
33. Some of the water quality parameters are
35. The presence of hardness in excess of
measured by titrating a water sample with a
permissible limit causes
titrant. Group-I gives a list of parameters and Group-IIgives the list of titrants.
(A)
Cardio
discoloration Group-I
Group-II
P.Alkalinity
1. N/35.5 AgNO3
Q. Hardness
2. N/40 Na2S2O3
R. Chloride
3. N/50 H2SO4
S. Dissolved oxygen
4. N/50 EDTA
Vascular (C)
problems
Calcium
(B)
deficiency
Skin (D)
Increased laundry expenses
36. The alkalinity and the hardness of a water sample are 250mg/L and 350 mg/L as , respectively. The water has (A) 350 mg/L carbonate hardness and zero noncarbonate hardness.
The correct match of water quality parameters in Group-I with titrants in Group-II is:
(B) 250mg/L carbonate hardness and zero noncarbonate hardness.
(A) P-1, Q-2, R-3, S-4 (B)P-3, Q-4, R-1, S-2 (C) 250mg/L carbonate hardness and 350 mg/L (C)P-2, Q-1, R-4, S-3 (D) P-4, Q-3, R-2, S-1
non-carbonate hardness.
34. Following chemical species were reported
(D) 250mg/L carbonate hardness and 100 mg/L
for water sample from a well:
non-carbonate hardness.
Species Concentration (milli equivalent/L)
37.
Chloride ( )
15
determination of 5-day, 20°C BOD on Monday.
Sulphate ()
15
Carbonate ()
05
A
student
began
experiment
for
th
Since the 5 day fell on Saturday, the final DO readings were taken on next Monday. On calculation, BOD (i.e. 7 day, 20°C) was found to be 150 mg/L. What would be the5-day, 20°C
BOD (in mg/L)? Assume value of BOD rate
41. An air parcel having 40ºC temperature
constant (k) at standard temperature of 20°C as
moves from ground level to 500m elevation in
0.23/day (base e). __________
dry air following the “adiabatic lapse rate”. The
38. An activated sludge system is operating at equilibrium with the following information. Wastewater related data: flow rate = 500
resulting temperature of air parcel at 500m elevation will be (A) 35ºC (B) 38ºC (C) 41ºC (D) 44ºC
m3/hour, influent BOD = 150 mg/L, effluent BOD = 10 mg/L. Aeration tank related data:
42. If the of a wastewater sample is
hydraulic retention time = 8 hours, mean-cell-
75mg/L and reaction rate constant k (base e) is
residence time = 240 hours, volume = 4000 m3,
0.345 per day, the amount of BOD remaining in
mixed liquor suspended solids = 2000 mg/L.
the given sample after 10 days is (mg/L
Q.a The food-to-biomass (F/M) ratio (in kg BOD
(A) 3.21 (B) 3.45 (C) 3.69 (D) 3.92
per kg biomass per day) for the aeration tank is
43. The reference pressure used in the
(A) 0.015 (B) 0.210 (C) 0.225 (D) 0 .240
determination of sound pressure level is
Q.b The mass (in kg/day) of solids wasted from
(A) 20µPa (B) 20db (C) 10µPa (D) 10db
the system is
44. Particulate matter (fly ash) carried in
(A) 24000 (B) 1000 (C) 800 (D) 33
effluent gases from the furnaces burning fossil fuels are better removed by
39. A coastal city produces municipal solid
(A) Cotton bag house filter (B) Electrostatic
waste (MSW) with high moisture content, high
precipitator (ESP) (C) Cyclone (D) Wet scrubber
organic materials, low calorific value and low inorganic materials. The most effective and sustainable option for MSW management in that city is
45. An aerobic reactor receives wastewater at a flow rate of 500 /d having a COD of 2000mg/L. The effluent COD is 400mg/L. Assuming
that
wastewater
contains
80%
(A) Composting (B) Dumping in sea (C)
biodegradable waste, the daily volume of
Incineration (D) Landfill
methane ( produced by the reactor is (A) 0.224 (B) 0.280 (C) 224 (D) 280
40. According to the Noise Pollution (Regulation and control) Rules, 2000, of the Ministry of Environment and Forests, India, the day time and night time noise level limits in ambient air
46. Column I P. Grit chamber
Column II 1. Zone settling
for residential areas expressed in dB(A) Leg are Q. Secondary settling tank 2. Stoke’s law (A) 50 and 40
(B) 55 and 45 R. Activated sludge process 3. Aerobic
(C) 65 and 55
(D) 75 and 70 S. Trickling filter
4. Contact stabilisation
The correct match of Column I with Column II is
50. The 5-day BOD of a wastewater sample is obtained as 190mg/I (with k = 0.01 ). The
(A) P-1,Q-2,R-3,S-4 (B) P-2,Q-1,R-3,S-4
ultimate oxygen demand (mg/I) of the sample will be
(C) P-1,Q-2,R-4,S-3 (D) P-2,Q-1,R-4,S-3
(A) 3800 (B) 475 (C) 271 (D) 190 47. Two primary air pollutants are
51. Match Group I (Terminology) with Group II
(A) sulphur oxide and ozone (B) nitrogen oxide
(Definition / Brief Description) for wastewater
and peroxyacetylnitrate (C) sulphur oxide and
treatment systems
hydrocarbon (D) ozone and peroxyacetynitrate
48.
Two
biodegradable
components
of
municipal solid waste are (A) plastics and wood (B) cardboard and glass (C) leather and tin cans (D) food wastes and garden trimmings
Group I
Group II
P. Primary treatment 1. Contaminant removal by physical forces Q. Secondary treatment 2. Involving biological and / or chemical reaction R. Unit operation
49. Group I lists estimation methods of some of
3. Conversion of soluble
organic matter to business
the water and wastewater quality parameters.
S. Unit process
Group II lists the indicators used in the
from incoming wastewater
4. Removal of solid materials
estimation methods. Match the estimation method (Group I) with the corresponding indicator (Group II). Group I
(C) P-3, Q-4, R-2, S-1 (D) P-1, Q-2, R-3, S-4 Group II
P. Azide modified Winklermethod for dissolved oxygen
1. Eriochrome Black T
Q. Dichromate method for chemical oxygen demand
(A) P-4, Q-3, R-1, S-2 (B) P-4, Q-3, R-2, S-1
2. Ferrion
R. EDTA titrimetric method for hardness 3. Potassium chromate
52. The dispersion of pollutants in atmosphere is maximum when (A) environmental lapse rate is greater than adiabatic lapse rate. (B) environmental lapse rate is less than adiabatic lapse rate. (C) environmental lapse rate is equal to adiabatic lapse rate.
S. Mohr or Argentometric method for chlorides
(D) maximum mixing depth is equal to zero.
4. Starch (A) P-3, Q-2, R-1, S-4 (B) P-4, Q-2, R-1, S-3 (C) P-4, Q-1, R-2, S-3 (D) P-4, Q-2, R-3, S-1
53. Two electrostatic precipitators (ESPs) are in series.
The
fractional
efficiencies
of
the
upstream and downstream ESPs for size are
80% and 65%. Respectively. What is the overall efficiency of the system for the same ?
D. both B and C 57. Which of the following sewage treatment methods has inherent problems of odour, ponding and fly nuisance?
(A) 100% (B) 93% (C) 80% (D) 65% A. UASB system 54. 50g of CO2 and 25g of CH4 are produced from the decomposition of municipal solid waste (MSW) with a formula weight of 120g. What is the average per capita green house gas production (g/day) in a city of 1 million people
B. Activated sludge process C. Trickling filters D. Stabilization ponds
with a MSW production rate of 500 ton / day? 58. From amongst the following sewage (A) 104 (B) 120 (C) 208 (D) 313
treatment options, largest land requirement for
55. The mean indoor air borne chloroform ()
concentration
in
a
room
was
a given discharge will be needed for A. Trickling filter
determined to be 0.4 . Use the following data: T= 293 K, P = 1 atmosphere, R =
.
This
concentration expressed in parts per billion
B. anaerobic pond C. Oxidation ditch
(volume basis, ppbv) is equal to
D. Oxidation pond
A. 1.0
59. Zero hardness of water is achieved by
B. 0.1 C. 0.2
D. 0.08
56. The results of analysis of a raw water
A. lime soda process
sample are given below. From this data it can be inferred that water needs removal of
B excess lime treatment
Turbidity
: 5 mg/l
C. ion exchange treatment
PH
: 7.4
D. excess alum and lime treatment
Fluorides
: 2.5 mg/l
60. A settling test on a sample drawn from aeration tank liquor of ASP (MLSS = 2800 mg/l)
Total hardness : 300 mg/l Iron
: 3 mg/l
MPN
: 50 per 100 ml
A. Turbidity, followed by disinfection B. Fluorides and hardness C. Iron, followed by disinfection
was carried out with 1 litre sample. Test yielded a settled volume of 200 ml. The value of sludge volume index shall be A. 14
B. 34.2
C. 71.4
D.271
61. Results of water sample analysis are as follows
Cation
Concentration (mg/l)
P
Q
R
S
A.
2
5
4
2
B.
4
1
6
4
C.
3
1
4
2
D.
2
1
6
3
Equivalent weight
40
23
10
12.2
55
20
2
39
(milli equivalent weight of =50 mg/meq) Hardness of the water sample in mg/l as is A. 44.8 B.89.5 C. 179 D. 358
64. Match the following Type
of
water
Method
of
impurity
treatment
P. Hardness
1. Reverse osmosis
Q. Brackish water 2. Chlorination
62. An ideal horizontal flow settling basin is 3 m deep having surface area 900 . Water flows at the rate of 8000 , at water
temperature 20 ( =
and
). Assuming stokes law to be valid, the proportion (percentage) of spherical
from sea
3. Zeolite treatment
R. Residual MPN from filters
4. Coagulation and flocculation
S. Turbidity
5.
Coagulation,
sand particles (0.01 mm in diameter with
flocculation
specific gravity 2.65), that will be removal is
filtration P
Q
R
S
A.
1
2
4
5
B.
3
2
2
4
C.
2
1
3
25
D.
3
1
2
5
A. 32.5 B. 67 C.87. D. 95.5 63. Match the following
Characteristics
of Allowable limit mg/l
sewage discharged in inland waters P.
1. 250
Q. COD
2. 30
65. A conventional activated sludge plant treating 1000 of municipal waste water disposes of its anaerobically digested sludge on relatively
R. Oil and grease
3. 20
S. Total suspended
4. 10
solids
5. 5
and
impervious
farmland.
Use
the
following data. 1. Raw sewage: SS=225 m g/l, (70 % volatile) BOD = 190 mg/l(Excess activated sludge returned to primary) 2. Primary settling : SS – 50 % removal, BOD – 30 % removal 3. Excess activated sludge : 0.4 g of VSS produced
6. 3
per gram BOD applied (80 % volatile of total) 4. Anaeroc digester: VSS reduced 50 %, digested sludge concentration – 60 % and sludge specific gravity-1 5. Application of farm land : 2
D. phenolphthalein indicator 68. The organism, which exhibits very nearly the characteristics of an ideal pathogenic indicator is
a. Total volatile suspended solids to be anaerobically digested (Kg/d VSS) shall be
A. Entamoeba histolytica B. Escherichia coli C. Salmonella typhi
D. Vibrio comma
A. 133 B. 168 C. 233 D. 245 b. Area requirement (ha) for disposal of the sludge on farmland shall be
69. An analysis for determination of solids in
the return sludge of activated sludge process was done as follows : (1) A crucible was dried to
A. 2.95 B. 1.95 C. 0.95 D. 0.55
a constant mass of 62.485 g. (2) 75 ml of a well66. A water treatment plant treating 10 mld of
mixed sample was taken in the crucible. (3) The
water
alum,
crucible with the sample was dried to a
( . The water has 6 mg/l of
constant mass of 65.020 g in a drying oven at
alkalinity as .
104 C. The crucible with the dried sample was
requires
20
mg/l
of
filter
a. Total alkalinity requirement ( as
) matching filter alum shall be A. 180 B. 120
C. 90 D. 60
placed in a muffle furnace at 600 C for an hour. After cooling, the mass of the crucible with residues was 63:145 g. The concentration of organic fraction of solids present in the return sludge sample is
b. Quantity of quick lime required (
as CaO) shall be
(a)
8800 mg/1
(b)
25000 mg/1
(c)
33800 mg/1 (d)
42600 mg/1
A. 2132 B. 3000 C. 4132 D. 6132 67. Most of the turbidity meters work on the
70. Water samples (X and Y) from two different
scattering principle. The turbidity value so
sources were brought to the laboratory for the
obtained is expressed in
measurement of dissolved oxygen (DO) using
A. CFU
B FTU C. JTU D. NTU
modified
Winkler
method.
Samples
were
transferred to 300 ml BOD bottles. 2 ml of
68. Hardness of water is directly measured by
MnSO4 solution and 2 ml of alkaliodide-azide
titration with ethylene-di amine tetra acetic
reagent were added to the bottles and mixed.
acid (EDTA) using
Sample X developed a brown precipitate, whereas
A. erichrome black –T indicator B. ferroin indictor C. methyl orange indicator
sample
Y
developed
a
white
precipitate. In reference to these observations, the correct statement is (a) Both the samples were devoid of DO
(b) Sample X was devoid of DO while sample Y contained DO
4-3-1
33
15
77
Using the above MPN Index table, the most
(c) Sample X contained DO while sample Y was devoid of DO (d) Both the samples contained DO 71. A portion of wastewater sample was subjected to standard BOD test (5 days, 20C), yielding a value of 180 mg/1. The reaction rate
probable number (MPN) of the sample is (a)
26
(b)
33
(c)
260
(d)
330
76.
The design parameter for flocculation is
given by a dimensionless number G t, where G is the velocity gradient and t is the detention
constant (to the base 'e') at 20C was taken as
time. Values of G t ranging from 10 to 10 are
0.18 per day. The reaction rate constant at
commonly used, with t ranging from 10 to 30
other temperature may be estimated by kr =
mm. The most preferred combination of G and t
k20 (1.047)
T20
. The temperature at which the
4
5
to produce smaller and denser floccus is
other portion of the sample should be tested, to exert the same BOD in 2.5 days, is
(a) large G values with short t
(a)
4.9 C
(b)
(b) large G values with long t
(c)
31.7 C
(d)
24.9 C
(c) small G values with short t
35.0 C
(d) small G values with short t 72. A standard multiple-tube fermentation test was conducted on a sample of water from a
77. Chlorine gas used for disinfection combines
surface stream. The results of the analysis for
with water to form hypochlorous acid (HOCl).
the confirmed test are given below.
The HOCl ionizes to form hypochlorite (OCl ) in a reversible reaction :
Sample Size (ml)
No. of positive
No. of negative
results
results out of 5
out of 5 tubes
tubes
-
HOCI H+ + OCl (k= 2.7 × 10 8 at 20C), the equilibrium of which is governed by pH. The -
1.0 0.1 0.01
4 3 1
sum of HOCI and OCl is known as free chlorine
1 2 4
residual and HOCI is the more effective disinfectant. The 90% fraction of HOCl in the
MPN Index and 95% confidence limits for combination of positive results when five tubes
free chlorine residual is available at a pH value (a)
4.8
(b)
6.6
(c)
7.5
(d)
9.4
used per dilutions (10 ml, 1.0 ml, 0.1 ml) Combination of MPN Index 95% confidence positives
78. In
per 100 ml limit
aerobic
environment,
nitrosomonas
convert Lower
Upper (a)
4-2-1
26
12
65
NH3 to NO2
(b)
-
-
NO2 to NO3
(c)
NH3 to N2O
-
(d)
NO2 to HNO3
R. Bacterial concentration
79. Total Kjedahl nitrogen is a measure of
S. Coagulant dose
(a) total organic nitrogen
Group 2 :
(b) total organic and ammonia nitrogen
1. BOD 2. MPN 3. Jar test 4. Turbidity
(c) total ammonia nitrogen
(a). P-2, Q-1, R-4, S-3
(b)
P-4, Q-1, R-2,S-3
(d) total inorganic and ammonia nitrogen
(c) P-2, Q-4, R-1, S-3
(d)
P-4, Q-2, R-1, S-3
80. 1 TCU is equivalent to the colour produced by
84. Match the following
(a) 1 mg/L of chlorplatinate ion
Group I
(b) 1 mg/L of platinum ion
P. Thickening of sludge
(c) 1 mg/L Platinum in form of chlorplatinate
Q. Stabilization of
ion
R. Conditioning of sludge S. Reduction of sludge
(d) 1 mg/L of organo-chlorplatinate ion
Group 2
81. Bulking sludge refers to having (a) (b)
1. Decrease in volume of sludge by chemical oxidation sludge
F / M < 0.3 / d
2. Separation of water by heat or chemical
0.3 / d < F / M < 0.6 / d
treatment (c) (d)
F / M = zero
3. Digestion of sludge
F / M > 0.6 / d
4. Separation of water by flotation or gravity
82. If tomato juice is having a pH of 4.1, the
(a) P-4, Q-3, R-1, S-2
(b) P-3, Q-2, R-4, S-1
hydrogen ion concentration will be
(c) P-4, Q-3, R-2, S-1
(d) P-2, Q-1, R-3, S-4
-5
(a) 10.94 X 10 mol/L -5
(c) 8.94 X 10 mol/L
-5
(b) 9.94 X 10 mol/L
85. Match the following
-5
(d) 7.94 X 10 mol/L
Group 1
Group 2
83. Group 1 contains some properties of water/
P. Release valve
wastewater and group 2 contains list of some
inlet pressure t lower outlet pressure
tests
on
water/waste
water.
Match
property with corresponding test.
1. Reduce high
the Q. Check valve
2. Limit the flow
of water to single direction Group 1 : R. Gate valve P. Suspended solids concentration Q. Metabolism of biodegradable organics
the pipeline
3. Remove air from
S. Pilot valve
4. Stopping the flow of
water in the pipeline
wastewater were diluted to 300 ml and incubated at 20C in BOD bottles for 5 days.
(a) P-3, Q-2, R-4, S-1 (b) P-4, Q-2, R-1, S-3
Sl. No.
Wastewater
Initial
DO After 5
Volume,
DO,
days, mg/L
(c) P-3, Q-4, R-2, S-1 (d) P-1, Q-2, R-4, S-3 86.
In
a
certain
situation,
mg/L
wastewater
1. 2. 3.
discharged into a river, mixes with the river water
instantaneously
and
completely.
Following is the data available :
5 10 50
9.2 9.1 8.4
6.9 4.4 0.0
Based on the data, the average BOD5 of the
Wastewater :
wastewater is equal to
DO = 2.00 mg/L Discharge rate = 1.10 m /s
(a) 139.5 mg/L (c) 109.8 mg/L
River water
89. A synthetic sample of water is prepared by
3
(b) 126.5 mg/L (d)72.2 mg/L
adding 100 mg Kaolinite (a clay minerla), 200 DO = 8.3 mg/L
mg glucose, 168 mg NacI, 120 mg MgSO4, and
3
Flow rate = 8.70 m /s
111 mg CaCI2 to 1 liter of pure water. The
Temperature = 20° C
concentrations of total solids (TS) and fixed
Initial amount of DO in the mixture of waste
solution in mg/L are equal to
and river shall be (a)
5.3 mg/L
(c)
7.6 mg/L
(b)
6.5 mg/L
(d)
8.4 mg/L
87. A city is going to install the rapid sand filter after
the
sedimentation
tanks.
Use
the
following data. Design loading rate to the 3
dissolved solids (FDS) respectively in the
2
3
(a)
699 and 599
(b)
599 and 399
(c)
699 and 199
(d)
699 and 399
90. The composition of a certain MSW sample and specific weights of its various components are given below.
filter 200 m /m d Design flow rate 0.5 m /s 2
Surface area per filter box 50m
Component
Percent by
Specific Weight
Weight
(kg/m )
a. The surface area required for the rapid sand filter will be 2
2
2
(a) 210 m (b) 215 m (c) 216 m
(d) 218 m
2
b. The number of filters required shall be (a) 3
(b)
4
(c)
6
(d)
8
88. To determine the BOD5 of a wastewater sample, 5, 10 and 50 ml aliquots of the
3
Food waste 50 300 Dirt and Ash 30 500 Plastics 10 65 Wood and Yard 10 125 waste 3 Specific weight (kg/m ) of the MSW sample is
(a) 319
(b) 217
(c) 209
(d) 199
91. In a rapid sand filter, the time for reaching particle breakthrough (TB) is defined as the time
elapsed from start of filter run to the time at
b. What is the minimum diameter of the
which the turbidity of the effluent from the
particle which can be removed with 100%
filter is greater than 2.5 NTU. The time for
efficiency in the above sedimentation tank?
reaching terminal head loss (TH) is defined as the time elapsed from the start of the filter run to the time when head loss across the filter is
(a) 11.8 × 10-3 mm (b) 16.0 × 10-3 mm (c) 50 × 10-3
(d) 160 × 10-3 mm
greater than 3m. 93. Particulate matter (fly ash) carried in a. The effect of increasing the filter depth (while
effluent gases from the furnaces burning fossil
keeping all other conditions same) on T B and
fuels are better removed by
TH is (A) Cotton bag house filter (B) Electrostatic (a) TB increases and TH decreases
precipitator (ESP) (C) Cyclone (D) Wet scrubber
(b) both T B and TH increase
94. A sludge from the aeration tank of the
(c) TB decreases and TH increases (d) both T B and TH decreases b. The effect of increasing the filter loading rate (while keeping all other conditions same) on TB and TH is
activated sludge process (ASP) has solids contents (by weight) of 2%. This sludge is put in a sludge thickner, where sludge volume is reduced to half. Assume that the amount of solids in the supernatant from the thickner is negligible, the specific gravity of sludge solids is 2.2 and the density of the wate r is 1000
(a) TB increases and TH decreases
a. What is the density ( )of the sludge
(b) both TB and TH increases
removed from the aeration tank
(c) TB decreases and TH increases
A. 900
(d) both TB and TH decreases
b. What is the solids content (by weight) of the
B. 1000 C. 1011 D. 1022
thickened sludge 92. A plain sedimentation tank with a length of 20m, width of 10 m, and a depth of 3 m is used in a water treatment plant to treat 4 million litres of water per day (4 MLD). The average temperature of water is 20°C. The dynamic viscosity of water is 1.002 x 10-3 N.s/ at 20°C. Density of water is 998.2 kg/ . Average specific gravity of particles is 2.65. a. What is the surface overflow rate (
in the sedimentation tank ? (a) 20 (b) 40 (c) 67 (d) 133
A. 3.96 % B. 4.00 % C. 4.04 % D. 4.10 % 95. A sample of domestic sewage is digested with silver sulphate, sulphuric acid, potassium dichromate and mercuric sulphate in chemical oxygen demand (COD) test. The digested sample is then titrated with standard ferrous ammonium sulphate (FAS) to determine the unreacted amount of (A) mercuric sulphate (B) potassium dichromate (C) silver sulphate
(D) sulphuric acid
96. In a domestic wastewater sample, COD and BOD were measured. Generally which of the following statement is true for their relative magnitude?
(A) 150
(B) 192
(C) 30
(D) 50
103. Aeration of water is done to remove (A) Suspended impurities (B) Colour
(A) COD = BOD
(B) COD > BOD
(C) Dissolved Salts
(C) COD < BOD
(D) Nothing can be said
104. The following chemical is used for
97. In disinfection, which of the following forms of chlorine is most effective in killing the
(D) Dissolve Gases
coagulation (A) Ammonium Chloride (B) Aluminium Chloride
pathogenic bacteria? (C) Aluminium Sulphate (D) Copper Sulphate (A) Cl
(B) OCl
(C) N Cl
(D) HOCl 105. The unit in which both sedimentation and
98. A trickling filter is designed to remove (A) Settleable Solids
(B) Colloidal Solids
digestion processes of sludge take place simultaneously is (A) Skimming Tank
(C) Dissolved Organic Matter
(B) Imhoff Tank
(C) Detritus Tank
(D) None of the above 99. In natural water, hardness is mainly caused
(D) Digestion Tank
106. If the of waste is 150 mg/L and the reaction rate constant (to the base ‘e’) at C is
by
0.35/day, the ultimate BOD in mg/L is
(A) (C)
and
and
(B) and (D)
and
(A) 97.5 (B) 181.5 (C) 212.9 (D) 230.5
100. For a water treatment plant having a flow
107. The concentration and concentration of a
rate of 432 /hr, what is the required plan area
water sample are 160 mg/lit and 40 mg/lit as
( ) of a Type I setting tank to remove 90% of
their ions respectively. The total hardness of
the particles having a settling velocity of 0.12
this water sample in terms of in mg/lit is
cm/sec is
approximately equal to
(A) 120
(B) 111
(C) 90
(D) 100
(A) 120
(B) 200
(C) 267
(D) 567
101. The theoretical oxygen demand mg/L of a
108. A town has an existing horizontal flow
0.001 mol/L glucose solution is
sedimentation tank with an overflow rate of 17
(A) 180
/day/, and it is desirable to remove particles that have settling velocity of
(B) 192 (C) 90
(D) 190
102. A wastewater sample has an initial BOD of
0.1mm/sec. Assuming the tank is an ideal
222 mg/L. The first order BOD decay coefficient
sedimentation tank, the percentage of particles
is 0.4/day. The BOD consumed (in mg/L) in 5
removal is approximately equal to
days is
(A) 30%
(B) 50%
(C) 70% (D) 90%
113. The following characteristics pertain to the sand filters used in water industry.
109. The BOD removal efficiency, in percentage, during
primary
treatment,
under
I. Filtration rate is 1 to 4 /( day).
normal
conditions is about
II. Typical duration of operation in one run is 24 to 72 hours.
(A) 65% (B) 85% (C) 30% (D) Zero III. Operating cost is low. 110. Critical factors for the activated sludge treatment process are
Which of the above characteristics pertain to slow sand filters?
(A) Maximum hourly flow rate. (A) I, II and III
(B) I and II
(C) II and III
(D) I and II
(B) Maximum and minimum flow rate. (C) Maximum hourly flow rate and maximum daily organic load.
114. Temporary hardness in water is caused by the presence of
(D) Minimum hourly flow rate and minimum daily organic load. 111. Use of coagulants such as alum (A) Results in reduction of pH of the treated
(A) Bicarbonates of Ca and Mg (B) Sulphates of Ca and Mg (C) Chlorides of Ca and Mg
water.
(D) Nitrates of Ca and Mg
(B) Results in increase of pH of the treated
115. Blue baby disease (methaemoglobinemia)
water.
in children is caused by the presence of excess
(C) Results in ho change in pH of the treated
(A) Chlorides (B) Nitrates
water (C) Fluoride (D) Lead (D) May cause and increase or decr ease of pH of the treated water.
116. Standard 5-day BOD of a waster water sample is nearly x% of the ultimate B OD, where x is
112. The disinfection efficiency of chlorine in water treatment
(A) 48 (B) 58 (C) 68 (D) 78
(A) Is not dependent on pH value. 117. The minimum dissolved oxygen content (B) Is increase by increased pH v alue. (C) Remains constant at all pH value. (D) Is reduced by increased pH value.
(ppm) in a river necessary for the survival of aquatic life is (A) 0
(B) 2
(C) 4
(D) 8
118. Chlorine is sometimes used in sewage
(a) device for distributing septic tank effluent to a soil absorption system (b) device for preventing overflow from elevated water storage tank (c) device for preventing crown corrosion of sewer (d) section of sewer which is dropped below the hydraulic grade line in order to avoid an obstacle.
treatment (A) To avoid flocculation (B) To increase biological activity of bacteria (C) To avoid bulking of activated sludge (D) To help in grease separation 119. Two samples of water A and B have pH values of 4.4 and 6.4 respectively. How many times more acidic sample A is than sample B? (A) 0
(B) 15
(C) 100
(D) 200
120. In a BOD test, 5 ml of waste is added to 295 ml of aerated pure water. Initial dissolved oxygen (D.O.) content of the diluted sample is 7.8 mg/l. After 5 days of incubation at 20°C, the D.O. content of the sample is reduced to 4.4 mg/l. The BOD of the waste water (mg/l ) is
125. Water distribution systems are sized to meet the (a) maximum hourly demand (b) Average hourly demand (c) maximum daily demand and fire demand (d) average daily demand and fire demand. 126. In a BOD test using 5% dilution of the sample (15 ML of sample and 285 mL of dilution water), dissolved oxygen values for the sample and dilution water blank bottles after five days 0 incubation at 20 C were 3.80 and 8.80 mg/L, respectively. Dissolved oxygen originally present in the undiluted sample was 0.80 mg/L. 0 The 5-day 20 C BOD of the sample (mg/L ) is (a) 116 (b) 108 (c) 100 (d) 92
(A) 196 (B) 200 (C) 204 (D) 208 121. Excessive fluoride in drinking water causes (a) Alzheimer’s disease (b) Mottling of teeth and embrittlement of bones (c) Methemoglobinemia (d) Skin cancer
122 Coagulation-flocculation with performed (a) immediately before chlorination (b) immediately after chlorination (c) after rapid sand filtration (d) before rapid sand filtration
alum
is
123. Sewage treatment in an oxidation pond is accomplished primarily by (a) alga-bacterial symbols (b) algal photosynthesis only (c) bacterial oxidation only (d) chemical oxidation only 124. An inverted siphon is a
127. For a flow of 5.7 MLD (million litres per day) and a detention time of 2 hours, the surface area of a rectangular sedimentation tank to remove all particles have setting velocity of 0.33 mm/s is 2 2 2 2 (a) 20m (b) 100m (c) 200m (d) 400m
