The disinfection efficiency of chlorine increases by_______________?

A. 1) decreasing the time of contact
B. 2) decreasing the temperature of water
C. 3) increasing the temperature of water
D. The correct answer is ?

The process in which the chlorination is done beyond the break point is known as_________________?

A. Prechlorination
B. Post chlorination
C. Super chlorination
D. Break point chlorination

The treatment of water with bleaching powder is known as________________?

A. Prechlorination
B. Super chlorination
C. Dechlorination
D. Hypochlorination

Which of the following chemical compounds can be used for dechlorination of water ?

A. Carbon dioxide
B. Bleaching powder
C. Sulphur dioxide
D. Chloramines

As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is___________________?

A. Smaller
B. Larger
C. Same
D. None of the above

In lime-soda process________________?

A. Only carbonate hardness is removed
B. Only non-carbonate hardness is re-moved
C. Lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness
D. Lime reduces the non-carbonate hard-ness and soda-ash removes the carbo¬nate hardness

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

A. Sodium sulphate
B. Copper sulphate
C. Sodium chloride
D. Calcium chloride

As compared to cast iron pipes, steel pipes are______________?

A. Heavier
B. Stronger
C. Costlier
D. Less susceptible to corrosion

The layout of distribution system in which water flows towards the outer periphery is_________________?

A. Ring system
B. Dead end system
C. Radial system
D. Grid iron system

Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system ?

A. Circle method
B. Equivalent pipe method
C. Hardy cross method
D. Electrical analysis method