এনভায়রনমেন্টাল ইঞ্জিনিয়ারিং Questions
41. The design period for a water supply project is taken as-
5 to 10 years
15 to 20 years
10 to 15 years
20 to 30 years
42. The presence of hydrogen sulphide in water causes-
softening
acidity
alkalinity
bad taste
43. The pH value of water for public supplies is limited from-
2.5 to 6.5
8 to 10.5
6.5 to 8.5
10.5 to 15
44. The open wells or dug wells are also known as-
shallow wells
percolation wells
draw wells
all of these
45. The most important source of water for public water supply is-
lake
pond
river
sea
46. The max" permissible total solid content in water for domestic purposes should not exceed-
300 ppm
400 ppm
500 ppm
1000 ppm
47. The maximum permissible colour for domestic supplies, on platinum cobalt scale is-
5 to 10 ppm
10 to 20 ppm
20 to 30 ppm
30 to 40 ppm
48. Sphere shaped bacteria are called-
spirilla
cocci
bacilli
trichobacteria
49. The maximum acidity in water will occur at a pH value of-
0
7
2
14
50. When the pH value of water is more than 7, it represents--- water.
neutral
alkaline
acidic
solt
51. The most common cause of acidity in water is-
hydrogen
carbon dioxide
oxygen
all of theese
52. The water bearing strata i.e. layers of sand, gravel etc. is called-
an aquifer
zone of saturation
an aquifuge
an aquiclude
53. The presence of bacteria in water causes-
hardness
diseases
alkalinity
bad taste
54. pH value is a symbol for ---concentration.
magnesium
hydrogen
calcium
sodium
55. The maximum permissible turbidity for domestic supplies, on silica scale is-
5 to 10 ppm
20 to 30 ppm
10 to 20 ppm
30 to 40 ppm
56. Suspended impurities consist of-
iron
bacteria
chlorine
all of these
57. The total count of bacteria per cubic centimeter for domestic purposes varies from-
0 to 100
150 to 200
100 to 150
200 to 250
58. The maximum permissible temperature for domestic supply is-
5 to 10°C
10 to 15°C
15 to 20°C
20 to 25°C
59. The groundwater is generally free from impurities.
suspended
dissolved
60. The quality of tube well water is ---as compaired to surface water
good
poor