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Environmental (61-80)

Updated: Apr 9, 2020

61. The process in which the chlorination is done beyond the break point is known as super chlorination


62. The percentage of chlorine in fresh bleaching powder is about

30 to 35


63. The treatment of water with bleaching powder is known as



64. The suitable method for disinfection of swimming pool water is ultra violet rays treatment


65. Which of the following chemical com pounds can be used; for dechlorination of water ? sulphur dioxide


66. In chlorination, with the rise in temperature of water, death rate of bacteria



67. As compared to higher pH values, the contact period required for efficient

chlorination at lower pH values is smaller


68. Disinfection efficiency is reduced at higher pH value of water


69. In lime-soda process lime reduces the carbonate hardness and soda-ash removes the non-carbonate hardness


70. The major disadvantage of lime soda process of water softening is that huge amount of precipitate is formed which creates a disposal problem


71. Which of the following compounds is widely used for algae control ?

copper sulphate


72. Activated carbon is used for removing odours


73. As compared to cast iron pipes, steel pipes are stronger


74. The suitable layout of a distribution system for irregularly growing town is

dead end system


75. The layout of distribution system in which water flows towards the outer periphery is radial system


76. The suitable layout of distribution system fox a city with roads of rectangular pattern is grid iron system


77. The commonly used material for watersupply pipes, which has the properties of being strong, not easily corroded and long life but is heavy and brittle is

cast iron


78. Hardy cross method of analysis of distribution system

involves successive trials,is time consuming


79. The method of analysis of distribution system in which the domestic supply is

neglected and fire demand is considered is circle method


80. Which of the following methods of analysis of water distribution system is

most suitable for long and narrow pipe system ? equivalent pipe method

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