Certification Action Line — Questions — April 2014

April 14, 2014

Questions about filters.

1.      Cationic (positively-charged) polymers are good coagulant aids for negatively charged suspended solids upstream of media filtration and polyamide-membrane reverse osmosis systems. (True or False)

2.      Polyamide RO membranes can be protected from carryover of cationic polymeric coagulant by pretreatment with a:

a.       media filter

b.      cartridge filter

c.       manganese greensand filter

d.      water softener

e.       activated carbon filter

3.      Birm is a manganese oxide coated media that can be used as an alternative to manganese greensand in some cases. (True or False)

4.      Birm should not be used on water:

a.       devoid of dissolved oxygen

b.      with hydrogen sulfide

c.       with oil

d.      with an acidic pH

e.       all of the above

5.      Activated carbon filtration is used in the removal of:

a.       dissolved organics

b.      suspended organics

c.       chlorine

d.      chloramines

e.       all of the above

6.      Activated carbon has greatest capacity for removal of:

a.       chlorine

b.      higher-molecular weight organics, such as pesticides and herbicides

c.       highly polar organic molecules, such as trihalomethanes

7.      After backwashing of a filter bed (e.g., an activated carbon filter), the filter should be forward rinsed to drain. (True or False)

8.      Cartridge filter elements that are most effective at removing particles the size of the manufacturer’s pore rating are:

a.       string-wound filters

b.      thermally-bonded spun-wound filters

c.       pleated membrane filters

d.      all of the above

9.      The most absolute sealing method between a cartridge filter element and its housing is a:

a.       knife-edge seal

b.      double O-ring seal

c.       single O-ring seal

10.  Cartridge filters should be replaced:

a.       when pressure differential across the filter exceeds 15 pounds per square inch

b.      every two months

c.       a and b

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