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)
Related Mcqs:
- Disinfection efficiency is________________?
A. reduced at higher pH value of water
B. unaffected by pH value of water
C. increased at higher pH value of water
D. highest at pH value equal to 7 - The suitable method for disinfection of swimming pool water is________________?
A. ultra violet rays treatment
B. lime treatment
C. by using potassium permanganate
D. chlorination - Disinfection of water results in______________?
A. removal of turbidity
B. removal of hardness
C. killing of disease bacteria
D. complete sterilisation - Residual chlorine in water is determined by________________?
A. starch iodide method
B. orthotolidine method
C. both (A) and (B)
D. none of the above - 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 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 - The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about______________?
A. 0.01 to 0.05 ppm
B. 0.05 to 0.5 ppm
C. 0.5 to 1.0 ppm
D. 1.0 to 5.0 ppm - The pathogens can be killed by_______________?
A. nitrification
B. chlorination
C. oxidation
D. none of the above - The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by_______________?
A. TOD>BOD>COD
B. TOD>COD>BOD
C. BOD>COD>TOD
D. COD>BOD>TOD - For a given discharge, the efficiency of sedimentation tank can be increased by______________?
A. increasing the depth of tank
B. decreasing the depth of tank
C. increasing the surface area of tank
D. decreasing the surface area of tank
