MCQOPTIONS
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MCQOPTIONS
This section includes 80 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Science knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The maximum removal of suspended and dissolved impurities from the sewage is |
| A. | 65 |
| B. | 70 |
| C. | 92 |
| D. | 99 |
| Answer» D. 99 | |
| 52. |
The design Hydraulic loading rate of the gravity thickener is _______ m3/m2/day. |
| A. | 20 |
| B. | 39 |
| C. | 40 |
| D. | 85 |
| Answer» B. 39 | |
| 53. |
Which of the following is the final stage in the sludge treatment process? |
| A. | Digestion |
| B. | Dewatering |
| C. | Drying |
| D. | Thickening |
| Answer» D. Thickening | |
| 54. |
State whether the following statement is true or false.Recirculation increases the efficiency of high rate trickling filters. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 55. |
Dorroco aerator is a type of |
| A. | Combined aerator |
| B. | Mechanical aerator |
| C. | Ridge and furrow type aerator |
| D. | Spiral flow type aerator |
| Answer» B. Mechanical aerator | |
| 56. |
The detention period of the Sheffield mechanical aeration tank is |
| A. | 15 hours |
| B. | 1minute |
| C. | 1 hour |
| D. | 4 hours |
| Answer» B. 1minute | |
| 57. |
The maximum temperature at which thermophilic microorganisms remain active in sludge digester is |
| A. | 60oC |
| B. | 40oC |
| C. | 30oC |
| D. | 20oC |
| Answer» B. 40oC | |
| 58. |
The dewatered sludge cannot be disposed by |
| A. | Composting |
| B. | Heat drying |
| C. | Acid fermentation |
| D. | Incineration |
| Answer» D. Incineration | |
| 59. |
Which of the following is obtained in the secondary tank in two stage sludge digester? |
| A. | Partially digested sludge |
| B. | Partially digested sludge and supernatant liquor |
| C. | Digested sludge and supernatant liquor |
| D. | supernatant liquor |
| Answer» D. supernatant liquor | |
| 60. |
The recirculation ratio for the low rate trickling filter is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 0 |
| Answer» E. | |
| 61. |
The process of removal of water from the sludge is called ______ |
| A. | Dewatering |
| B. | Thickening |
| C. | Digestion |
| D. | Drying |
| Answer» B. Thickening | |
| 62. |
The organic loading in a trickling filter is measured in |
| A. | m3/day |
| B. | gm/m2/day |
| C. | Kg/hectare-meter/day |
| D. | Kg/hectare/day |
| Answer» D. Kg/hectare/day | |
| 63. |
State whether the following statement is true or false.BOD of sewage is dependent on food to microorganism ratio. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 64. |
The recirculation factor in a low rate trickling filter is |
| A. | 0 |
| B. | 1 |
| C. | 10 |
| D. | 100 |
| Answer» C. 10 | |
| 65. |
Hopper bottom vertical flow type tank is _____ in shape. |
| A. | Circular |
| B. | Triangular |
| C. | Rectangular |
| D. | Elliptical |
| Answer» B. Triangular | |
| 66. |
State whether the following statement is true of false.The flow of sewage in the sewers is independent of the its slope and geometry. |
| A. | True |
| B. | False |
| Answer» C. | |
| 67. |
A circular sewer having 0.4m diameter is flowing with velocity 2m/Sec. If the gradient of sewer is 1 in 90. Find the value of Chezy's coefficient? |
| A. | 10 |
| B. | 30 |
| C. | 60 |
| D. | 40 |
| Answer» E. | |
| 68. |
The diameter of a circular sewer is 0.8m. The desired depth of flow is |
| A. | 2/3 of the circular section of sewer |
| B. | 1/3 of the circular section of sewer |
| C. | 1/2 of the circular section of sewer |
| D. | 1/4 of the circular section of sewer |
| Answer» B. 1/3 of the circular section of sewer | |
| 69. |
The value of manning's coefficient for cement concrete is |
| A. | 0.017 |
| B. | 0.13 |
| C. | 0.013 |
| D. | 0.17 |
| Answer» D. 0.17 | |
| 70. |
The non scouring velocity is 260cm/Sec. The type of material of the sewer is |
| A. | Earth channels |
| B. | Stone ware sewers |
| C. | Brick lined sewer |
| D. | Cement concrete sewer |
| Answer» E. | |
| 71. |
One side walkway is a type of |
| A. | Circular cross section |
| B. | Channel cross section |
| C. | Ovoid cross section |
| D. | Arch cross section |
| Answer» C. Ovoid cross section | |
| 72. |
The arch cross section is divided into how many types? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» C. 4 | |
| 73. |
State whether the following statement is true or false.The septic tank and pump chamber should be kept as deep as possible. |
| A. | True |
| B. | False |
| Answer» C. | |
| 74. |
_______ is used to remove the waste directly from the building. |
| A. | Branch sewer pipe |
| B. | Outfall sewer pipe |
| C. | Soil vent pipe |
| D. | Main sewer pipe |
| Answer» D. Main sewer pipe | |
| 75. |
_______ condition exist when the sewer is laid at a depth between 9m to 12m. |
| A. | Trench ditch |
| B. | Trench |
| C. | Tunnel |
| D. | Embankment |
| Answer» D. Embankment | |
| 76. |
The manhole in which vertical pipe is used for the transfer of sewage from branch to main sewer is |
| A. | Deep manhole |
| B. | Ramp |
| C. | Drop manhole |
| D. | Normal manhole |
| Answer» D. Normal manhole | |
| 77. |
State whether the following statement is true or false.The removal of BOD is independent of the loading conditions in infiltration process. |
| A. | True |
| B. | False |
| Answer» C. | |
| 78. |
How many stages are there in sludge digestion process? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» C. 4 | |
| 79. |
The detention period of a secondary clarifier is |
| A. | 30 minutes |
| B. | 1 hour |
| C. | 2 hours |
| D. | 4 hours |
| Answer» D. 4 hours | |
| 80. |
Which of the following process is not involved in the treatment of sludge? |
| A. | Dewatering |
| B. | Drying |
| C. | Flocculation |
| D. | Conditioning |
| Answer» D. Conditioning | |