51. Nitrogen oxides (NOx) is not produced in the __________ industry.
52. World's worst radioactive pollution was caused by nuclear reactor disaster which occured in
53. Dissolved oxygen content in river water is around __________ ppm.
54. Oil and grease present in an emulsified state in waste water discharged from industries can be removed by
55. The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated.
56. Particles having diameter greater than 75 μm (micrometer = 10-6 mm) are called
57. Which of the following is the most severe air pollutant ?
58. Presence of bacteria in potable (drinking) water causes
59. What are the methods of treatment & disposal of radioactive wastes ?
60. Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in
61. Main pollutant present in automobile exhaust is
62. Maximum allowable noise exposure limits for a man working for 8 hours a day in a noisy chemical plant is about __________ decibels.
63. Industrial workers working in leather tanning & manufacturing units are prone to suffer from
64. Peroxyacyl nitrate (PAN), a pollutant is found in the
65. Foaming and priming in boiler operation can be reduced by reduction in __________ in feed water.
66. Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools).
67. Which of the following radioactive wastes emits all α, β & γ rays and hence is the most hazardous of all radioactive emitters?
68. COD of raw municipal sewage may be in the range of about __________ mg/litre.
69. Maximum permissible turbidity in potable water is __________ ppm.
70. Presence of __________ hardness is responsible for the temporary hardness in water.
71. Dose of chlorine for disinfection of water is about __________ mg/litre of water.
72. A shallow pond in which the sewage is retained and biologically treated is called
73. Which is the most practical and economical method for removal of suspended solid matter from polluted water ?
74. Atmospheric pollution caused by the exhaust gas of supresonic transport air-crafts is mostly in the atmospheric region called
75. Iron & manganese present in the polluted water is removed by