Alkalinity in water is expressed as milli-grams per litre in terms of equivalent_______________?
(A) calcium carbonate
(B) magnesium carbonate
(C) sodium carbonate
(D) calcium hydroxide
The most common cause of acidity in water is_______________?
(A) carbon dioxide
(B) oxygen
(C) hydrogen
(D) nitrogen
The percentage of chlorine in fresh bleaching powder is about________________?
(A) 10 to 15
(B) 20 to 25
(C) 30 to 35
(D) 40 to 50
Chlorine demand of water is equal to________________?
(A) applied chlorine
(B) residual chlorine
(C) sum of applied and residual chlorine
(D) difference of applied and residual chlorine
The rate of Alteration of pressure filters is_________________?
(A) less than that of slow sand filters
(B) in between the filtration rate of slow sand filters and rapid sand filters
(C) greater than that of rapid sand filters
(D) equal to that of slow sand filters
The percentage of filtered water, which is used for backwashing in rapid sand filters, is about______________?
(A) 0.2 to 0.4
(B) 0.4 to 1.0
(C) 2 to 4
(D) 5 to 7
Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters. Reason R : The sand used in slow sand filters is finer than that in rapid sand filters. Select your answer based on the coding system given below?
(A) Both A and R are true and R is the correct explanation of A
(B) Both A and R are true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
The effective size of sand particles used in slow sand filters is_______________?
(A) 0.25 to 0.35 mm
(B) 0.35 to 0.60 mm
(C) 0.60 to 1.00 mm
(D) 1.00 to 1.80 mm
In water treatment, rapid gravity filters are adopted to remove_______________?
(A) dissolved organic substances
(B) dissolved solids and dissolved gases
(C) floating solids and dissolved inorganic solids
(D) bacteria and colloidal solids
The alum, when added as a coagulant in water_______________?
(A) does not require alkalinity in water for flocculation
(B) does not affect pH value of water
(C) increases pH value of water
(D) decreases pH value of water