321. Phosphorus can be removed from waste water by ferric chloride addition
322. Which of the following compounds does not provide free chloride ? NHCI₂
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 isfalse
d) A isfalse but R is true.
323. Assertion A : Alum or aluminum sulphate is widely used for the purpose of
flocculation in water treatment.
Reason R : It is effective even in the absence of alkalinity in the raw water
324. Assertion A : Microbiological examinations of water samples are usually based
on tests for the detection and enumeration of indicator organisms rather than of
Reason R : The identification of pathogens in water is both extremely time
consuming and difficult
325. Assertion A : Tapered flocculation is more efficient when compared to the
conventional process of flocculation.
Reason R : In tapered flocculation,velocity gradient at the inlet is less than
that at the outlet of the flocculation unit
326. Assertion A : In wastewater treatment, waste stabilization ponds are more
successful in sunny tropical regions.
Reason R : The bacterial action of purification is achieved through photo
327. Assertion A : Presence of E-coli bacteria in water indicates that the water is
polluted with facal discharge.
Reason R : E-coli is a pathogenic bacteria.
328. Assertion A : Ozone is not widely used in community water supplies.
Reason R : It is not possible to maintain residual concentration of ozone in water
after the disinfection process.
329. Assertion A : In the case of dual media filter, the rate of fiIteration is more than that of rapid sand filter.
Reason R : The direction of flow is from fine medium to coarse medium
330. Assertion A ,: Horizontal velocity of flow through grit chambers is maintained
between 24 to 30 cm/sec.
Reason R : Removal of organic and inorganic particles larger than O.l mm
direction is very essential
331. Assertion A : At the ferrule point of a water supply distribution pipe network for Indian towns having a majority of two storey buildings, the ideal minimum
pressure head of water is 12 m.
Reason R : This magnitude of pressure head at ferrule is necessary to reach the
highest floor of the two-storey buildings
332. Assertion A : Sanitary landfills can no longer be used for the disposal of solid
wastes in India.
Reason R : The leachates from sanitary landfills may pollute the ground water