PRACTICE EXAM QUESTIONS WITH
CORRECT ANSWERS
in certain costal areas, intrusion of sea water in to groundwater basin is most
commonly caused by? - CORRECT-ANSWERSover pumping from the ground
basin
noncarbonate hardness can only be reduces by the following processes: -
CORRECT-ANSWERSna2co3, ion exchange, membrane separation, and naoh.
selective carbonate removal is: - CORRECT-ANSWERSremoval lf calcium
bicarbonate hardness at 9.6 Ph
noncarbonate hardness is present in water when: - CORRECT-ANSWERStotal
hardness is greater than total alkalinity
ion exchange softening will remove: - CORRECT-ANSWERSnoncarbonate
hardness
the following constituents cause non carbonate hardness: - CORRECT-
ANSWERScaso4, cacl2, mgcl2, mgo4, and srso4
selective carbonate removal is: - CORRECT-ANSWERSremoval of calcium
bicarbonate hardness at Ph 9.6
selective carbonate removal is: - CORRECT-ANSWERSremoval of calcium
bicarbonate hardness at Ph 9.6
the softening process samples indicate the following data: t alk:90, p alk: 40.
Treatment parameters call for a treatment range of +2 to +5 hydroxide
alkalinity. the achieve this the: - CORRECT-ANSWERSlime feed should be
increased.
na2co3 hardness is present in water when: - CORRECT-ANSWERSthe total
alkalinity is greater than the total hardness
ion exchange will NOT reduce: - CORRECT-ANSWERSthe tds of water
, with ion exchange, the exchange capacity is based on: - CORRECT-
ANSWERSvolume and type of media
the capacity of synthetic ion exchange is lessened when: - CORRECT-
ANSWERSmg hardness is in excess of one half of the ca hardness.
slaking lime produces: - CORRECT-ANSWERScalcium hydroxide
selective carbonate hardness removal requires the use of: - CORRECT-
ANSWERSlime
you are operating a lime softening plant where magnesium removal is
necessary. The process includes lime addition, recarbonation, and filtration.
To maintain the quality of treatment and reduce operation cost, you should: -
CORRECT-ANSWERSeliminate recarbonation and use split treatment to lower
the Ph and save on lime
you are operation a lime softening plant which produces a finished water
with a total hardness of 80 mg/l as caco3 and a langlier index of +0.6. The
problem here is: - CORRECT-ANSWERSthe finished water will be scale
forming. excessive calcium carbonate caused this problem
recarbonation is necessary after lime softening in order to : - CORRECT-
ANSWERSreduce the scale forming tendencies of supersaturated water
in split treatment, a portion of the water, about 90%, is treated with an
excess amount of lime to remove __________ at a ph of over ______ -
CORRECT-ANSWERSmagnesium / 11
if the finished water from an ion exchange unit has a salty taste to it, a
probable cause for the problem may be: - CORRECT-ANSWERSthe rinse stage
was unsuccessful.
the primary cause of resin breakdown in the exchange softening process is :
- CORRECT-ANSWERSthe presence of high chlorine residual
__________________ is used to remove noncarbonate hardness in chemical
precipitation. - CORRECT-ANSWERSsodium carbonate
in ion exchange softening, if iron in the form of ferric is found in the water,
the unit will: - CORRECT-ANSWERSact as a filter
in ion exchange a high chlorine residual will: - CORRECT-ANSWERSdamage
the resin