Quiz: Civil Engineering 3 Oct 2020

Quiz: Civil Engineering
Exam: SSC-JE
Topic: Environmental Engineering

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes

Q1. Water is considered ‘hard’, if its hardness is of the order of
(a) 50 ppm
(b) 100 ppm
(c) 150 ppm
(d) 300 ppm

Q2. Phenolphthalein indicator is used to determine the alkalinity above pH
(a) 8.3
(b) 7.0
(c) 6.5
(d) 4.5

Q3. Total Kjeldahl nitrogen is a measure of
(a) total organic nitrogen
(b) total organic and ammonia nitrogen
(c) total ammonia nitrogen
(d) total inorganic and ammonia nitrogen

Q4. Which one of the following sequences is the most suitable for treating raw surface water to make it suitable for drinking purpose?
(a) Screeing→ filtration→ sedimentation→ disinfection
(b) Screening → disinfection → sedimentation → filtration
(c) Screening → sedimentation→ disinfection→ filtration
(d) Screening → sedimentation → filtration → disinfection

Q5. ‘Air binding’ may occur in
(a) Sewers
(b) Artesian well
(c) Aerator
(d) Filters

Q6. A heterotroph is an organism that obtains
(a) its cell carbon from an inorganic source
(b) its energy from the oxidation of simple inorganic compounds
(c) its cell carbon as well as its energy from organic matter
(d) its energy from a natural ecosystem

Q7. Shallow ponds in which dissolved oxygen is present at all depths are called
(a) aerobic lagoons
(b) aerobic ponds
(c) facultative lagoons
(d) facultative ponds

Q8. In the facultative pond systems, the aerobic zone may get extended downwards due to
(a) calm waters along with weak sunlight
(b) mixing by wind action along with weak sunlight
(c) mixing by wind action along with penetration by sunlight
(d) calm waters along with penetration by sunlight

Q9. Presence of Nitrogen in the waste water sample is due to the decomposition of :
(a) Carbohydrates
(b) Proteins
(c) fats
(d) Vitamins

Q10. The ultimate BOD value of a waste :
(a) Increase with temperature
(b) Decrease with temperature
(c) Remains the same at all temperatures
(d) Double with every 10°C rise

SOLUTIONS

S1. Ans.(c)

Sol.

Classification Hardness (mg/l)
Soft water 0 – 60
Moderate hard water 61- 120
Hard water 121 – 180
Very hard water ≥ 181

S2. Ans.(a)
Sol. phenolphthalein indicator turns water into pink colour, if the pH is more than 8.3 then phenolphthalein is a basic indicator.

S3. Ans.(b)
Sol. ▭(free Ammonia+organic Ammonia =Kheldahl Ammonia)

S4. Ans.(a)
Sol. the most suitable sequence for treating raw surface water to make it suitable for drinking purpose is
Screening → filtration → sedimentation → dis-infection

S5. Ans.(d)
Sol. Operational problem in rapid sand filter are –
– Air binding
– Mud ball formation
– Cracking of filter

S6. Ans.(c)
Sol. Autotrophs → Derive both material (cell carbon) and energy from inorganic substances.
Heterotrophs → Derive both material (cell carbon) and energy from organic substances.

S7. Ans.(b)
Sol. Shallow ponds in which dissolved oxygen is present at all depth are called Aerobic ponds. The bulk of the oxygen in ponds is provided by photosynthesis and some oxygen is provided by diffusion from the air.

S8. Ans.(c)
Sol. Aerobic conditions are maintained in the upper portions of the facultative pond by oxygen generated by algae and to lesser extent by penetration of atmospheric oxygen. Mixing by wind action and penetration by sunlight may extend the aerobic area downward.

S9. Ans.(b)
Sol. Presence of nitrogen in the waste water sample is due to the decomposition of proteins. Nitrogen is produced from metabolism in form of urea, uric acid and ammonia.

S10. Ans.(c)
Sol. Ultimate BOD represent the bio-degradable organic matter, so it will remain unchanged.

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