এনভায়রনমেন্টাল ইঞ্জিনিয়ারিং MCQ
সিভিল ইঞ্জিনিয়ারিং এ চাকরি প্রস্তুতির জন্য "এনভায়রনমেন্টাল ইঞ্জিনিয়ারিং" সাবজেক্টের সকল MCQ এই ফোল্ডারে পাবেন। Civil Engineering এর চাকরি নিয়োগ, রেজাল্ট, সাজেশন, অনলাইন ক্লাসের জন্য আমাদের App: Engineering Classroom গুগল প্লে-স্টোর থেকে ডাউনলোড করে নিন। Environmental MCQ
21. Biochemical Oxygen Demand (BOD) of safe drinking water must be-
0
50
10
100
22. The amount of chlorine used for plain b chlorination of water is about-
0.2 ppm
0.3 ppm
0.4 ppm
0.5 ppm
23. The effective size of sand particles for slow sand filters varies from- 0.3 to 0.35mm 0.35 to 0.5mm 0.5 to 0.65mm 0.65 to 0.75mm
0.3 to 0.35mm
0.35 to 0.5mm
0.5 to 0.65mm
0.65 to 0.75mm
24. The human excreta is a ---waste.
dry
liquid
semi-liquid
solid
25. The percentage of chlorine in fresh bleaching powder is-
20 to 25%
25 to 30%
30 to 35%
35 to 40%
26. The time of contact for chlorination should be at least-
5 minutes
20 minutes
1 hour
2 hours
27. Rapid sand filter can remove bacteria upto an extent of-
60 to 70%
70 to 80%
80 to 90%
90 to 99%
28. The velocity of flow in any sedimentation tank should not exceed-
0.05mm/s
5mm/s
0.5mm/s
50mm/s
29. The detention time for an ordinary plain sedimentation tank is-
1 to 2 hours
6 to 8 hours
2 to 4 hours
20 to 24 hours
30. The water from kitchens, bathrooms, wash basins is called-
sewage
raw sewage
sullage
none of this
31. Slow sand filter is more efficient for the removal of-
bacteria
turbidity
odour
all of these
32. The internal diameter of the sewer should not be less than-
15cm
25cm
50cm
75cm
33. The cross-section recommended for separate system of sewerage is--
circular
rectangular
egg-shaped
none of these
34. Cleaning period for a rapid sand filter is taken as-
2 to 3 hours
2 to 3 days
2 to 3 weeks
2 to 3 months
35. The coefficient of uniformity for slow sand filters is-
1.35
1.75
1.55
2.05
36. By lime soda process, hardness can be reduced to less than
50 ppm
75 ppm
150 ppm
100 ppm
37. Rapid sand filter can remove turbidity from water upto an extent of-
15 to 25 ppm
25 to 35 ppm
35 to 40 ppm
40 to 50 ppm
38. The process of killing pathogenic bacterias from water is called-
sedimentation
coagulation
filteration
disinfection
39. The minimum size of a fire hydrant is--
5cm
10cm
15cm
20cm
40. The aeration of water is done to remove--
colour
taste
odour
all of these