Environment 2 Flashcards
Which of the following chemicals is used for coagulation?
Aluminium sulphate
Alum is
Cougulant
In water supply scheme for what purpose the aeration is carried out? (2005,2015,2017) A.
To remove taste and odour
To disinfect the swimming pool water, which 9 one is used?
Chlorine
. In the case of surface water if pH ranges from 6 to 8, then which is the most suitable coagulant
Alum
Air binding in rapid sand filter is encountered
There is execcive negative head
Which one of the following forms of chlorine has no disinfecting property?
Trichloromin
Ph<4.4
Trichloromin
4.4-5.4
Dichloromine
Ph 5.4-8.4
Both mono dichloromine
Ph>8.4
Monichloromine
Oil and grease can be removed by (2010
Floatation tanks
Plain chlorination is done after
Filtration
The first stage in water treatment is (2010)
Sedimentation
The bacterial efficiency of a rapid sand filter
90%
Which of the following test reveals the amount of residual chlorine in treated water? (2010
• Orthotolidine test
• D.P.D test
Chlorotex test
Starch iodide test
Cleaning of slow sand filters is done by
Scraping of top layer of 15-30 mm thickness
Which of the following will result in appear- ance of residual chlorine in water? (2012
Break point chlorination
The method of deaning the rapid sand filters
Agitation and back washing
The strength of chlorine in fresh bleaching powder is
30-35%
Sedimentation with coagulation is done to
To remove fine colloidal particles
Which law is applicable for sedimentation of discrete particles in plain sedimentation
Stokes law
The application of chlorine beyond the stages of break point is known as
Super chlorination
Which one of the following filters should be recommended for protected rural water sup- ply project
Slow sand filter
What is defined as the difference between the amount of chlorine added to water and the amount of chlorine remaining at the end of a specified contact period
Chlorine demand
The settling of particles in sedimentation tank depends upon
Both length and breadth
The suitable method of distribution for a city with haphazard growth pattern (2016
Tree system
The amount of residual chlorine left in the public water supply for safety against patho- genic bacteria is
0.05-0.5 ppm
Which treatment process is carried out after filtration of water?
Disinfectantion
Maximum detention period of a clarifier used
2-3 hr
Detention period of Grit chamber is kept as
1 minutes
In water treatment, rapid gravity filters are adopted to remove
Bacteria and colloidal solids
