Disinfection Flashcards
Which of the following is not a common reason for disinfecting WWTP effluent?
a) Protect public water supplies
b) Protect receiving waters used for direct contact recreational purposes
c) Reduce turbidity, colour and odour for industrial users
d) Reduce coliform concentrations in shellfish growing areas
c) Reduce turbidity, colour and odour for industrial users
A treatment plant receives a constant pumped flow of 98 L/s from an equalization basin. If the chlorinator is set to dose at 18 mg/L how many kilograms of chlorine will be used in 24 hours?
a) 68 kg
b) 73.5 kg
c) 130.6 kg
d) 152.4 kg
d) 152.4 kg
The withdrawal rate of gaseous chlorine from a tonne cylinder should not exceed:
a) 68 Kg/day
b) 180 Kg/day
c) 400 Kg/day
d) 908 Kg/day
b) 180 Kg/day
Which of the following statements summarizes the reactions which take place during breakpoint chlorination?
a) Ammonia present in wastewater combines with ions of iron and manganese
b) Ammonia present in wastewater is destroyed by reacting with sulfur dioxide
c) Chloramines are ultimately destroyed by the addition of additional chlorine resulting in a free chlorine residual
d) Ammonia remains unchanged
c) Chloramines are ultimately destroyed by the addition of additional chlorine resulting in a free chlorine residual
Sodium Hypochlorite is available as a liquid solution or in dry powder form.
a) True
b) False
b) False
Which of the following is not a disinfection mechanism of the ozonation process:
a) Destruction of the cell wall and lysing of cell contents
b) Disruption of cellular enzymes at the 253 nm wavelength
c) Reactions with hydroxyl radicals
d) Damage to nucleic enzymes
b) Disruption of cellular enzymes at the 253 nm wavelength
In open channel UV disinfection systems the lamps may be aligned:
a) Parallel or vertical to the direction of flow
b) At a 45 ̊angle to the direction of flow
c) Above the flow to keep them dry
a) Parallel or vertical to the direction of flow
Which of the following factors does not affect the efficiency of the UV disinfection process:
a) Contact Time
b) UV Transmittance
c) Turbidity measured as NTUs
d) Dissolved oxygen concentration
d) Dissolved oxygen concentration
The germicidal portion of the UV bandwidth lies between 220 and 320 nm. This range is known as
a) UV-A
b) UV-B
c) UV-C
d) UV-D
c) UV-C
A good quality sunscreen with a sun block factor of at least SPF40 provides adequate skin protection when working around ultra violet light.
a) True
b) False
b) False
Chlorine dioxide (ClO2) like chlorine and sulfur dioxide can be obtained in 908 kg containers.
a) True
b) False
b) False
