Environmental Engineering 7

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Civil Engineering MCQ. PWD, CPWD, RRB, SSC, Mock Test Paper

Subject: Environmental Engineering 7

Part 1: List for questions and answers of Environmental Engineering II

Q1.The minimum recommended diameter of sewers, is
a) 5 cm
b) 10 cm
c) 15 cm
d) 20 cm

Q2.Aerobic bacteria’s
a) Flourish in the presence of free oxygen
b) Consume organic matter as their food
c) Oxidise organic matter in sewage
d) All the above

Q3.The rate of accumulation of sludge in septic tanks is recommended as
a) 30 litres/person/year
b) 25 litres/person/year
c) 30 litres/person/month
d) 25 litres/person/month

Q4.If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is
a) 200 ppm
b) 225 ppm
c) 250 ppm
d) None of these

Q5.If the diameter of sewer is 225 mm, the gradient required for generating self cleansing velocity, is
a) 1 in 60
b) 1 in 100
c) 1 in 120
d) None of these

Q6.The non-clog pump which permits solid matter to pass out with the liquid sewage, is
a) Centrifugal pump
b) Reciprocating pump
c) Pneumatic ejector
d) None of these

Q7.In olden days the type of section adopted in trunk and out fall sewers was
a) Parabolic shaped
b) Horse shoe shaped
c) Egg shaped
d) Circular shaped

Q8.For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed
a) 3 ppm
b) 4 ppm
c) 5 ppm
d) 10 ppm

Q9.In a fully mechanised composting plant, involves
a) Mechanized receipt
b) Mechanized segregation
c) Mechanized pulverising of refuse
d) All of these

Q10.When drainage to sewage ratio is 20, the peak dry weather flow is
a) 20% of the design discharge
b) Slightly less than 5% of the design discharge
c) Slightly more than 5% of the design discharge
d) None of these

Q11.The screens are fixed
a) Perpendicular to the direction of flow
b) Parallel to the direction of flow
c) At an angle 30° to 60° to the direction of flow
d) None of these

Q12.Pick up the in-correct statement from the following:
a) Manholes are provided in sewer pipes at suitable intervals
b) Catch basins are generally provided in sewers for carrying drainage discharge
c) Inlets are generally provided in all sewers
d) None of these

Q13.Clogging of sewers, is caused due to
a) Low discharge
b) Greasy and oily matters
c) Domestic wastes thrown in manholes
d) All the above

Q14.The coagulant widely used for sewage treatment, is
a) Alum
b) Ferric chloride
c) Ferric sulphate
d) Chlorinated copperas

Q15.The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is
a) 1.5
b) 2.0
c) 3.0
d) 4.0

Q16.Dilution method of disposing of sewage, is not preferred to
a) When diluting water has high dissolved oxygen content
b) When diluting water is used for water supply near the point of sewage disposed
c) When the diluting water is having flow currents
d) None of these.

Q17.If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is
a) 1045 mm
b) 1065 mm
c) 1075 mm
d) 1095 mm

Q18.The ratio of minimum hourly flow to the average flow of sewage is
a) 1/4
b) 1/3
c) 1/2
d) 3/4

Q19.Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to
a) Initial demand
b) First stage demand
c) Carbonaceous demand
d) All of these

Q20.Flocculated particles do not change their
a) Size
b) Shape
c) Weight
d) None of these

Part 1: List for questions and answers of Environmental Engineering II

Q1. Answer: c

Q2. Answer: d

Q3. Answer: a

Q4. Answer: c

Q5. Answer: c

Q6. Answer: a

Q7. Answer: b

Q8. Answer: b

Q9. Answer: d

Q10. Answer: b

Q11. Answer: c

Q12. Answer: c

Q13. Answer: d

Q14. Answer: b

Q15. Answer: b

Q16. Answer: b

Q17. Answer: d

Q18. Answer: b

Q19. Answer: d

Q20. Answer: d