Period of cleaning of slow sand filters is about________________?
A. 24 – 48 hours
B. 10-12 days
C. 2-3 months
D. 1-2 year
Environmental Engineering
Disinfection of water results in______________?
Disinfection of water results in______________?
A. removal of turbidity
B. removal of hardness
C. killing of disease bacteria
D. complete sterilisation
Double filtration is used_______________?
Double filtration is used_______________?
A. to increase the filtration slow sand filters capacity of
B. to increase the filtration rapid sand filters capacity of
C. for isolated buildings like pools, hotels etc swimming
D. all of the above
The disinfection efficiency of chlorine increases by_______________?
The disinfection efficiency of chlorine increases by_______________?
1) decreasing the time of contact
2) decreasing the temperature of water
3) increasing the temperature of water
The correct answer is ?
A. only (1)
B. both (1) and (2)
C. both (1) and (3)
D. only (3)
The process in which the chlorination is done beyond the break point is known as_________________?
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________________?
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 ?
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___________________?
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________________?
B. only non-carbonate hardness is re-moved
C. lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness(Correct)
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 ?
Which of the following compounds is widely used for algae control ?
A. sodium sulphate
B. copper sulphate
C. sodium chloride
D. calcium chloride