REHS EXAM Question and Answer 2026 |
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• The presence of which of the following is most easily identified by laboratory
analysis in water contaminated by feces?
a. shigella dysenteriae
b. coliform
c. entamoeba histolytica
d. salmonella typhosa -✓✓coliform
• Which of the following disinfecting compounds can be used in full strength for
disinfecting?
a. perchloron
b. calcium hypochlorite
c. chlorinated lime
d. sodium hypochlorite -✓✓sodium hypochlorite
• This substance is the first product of the decomposition of organic matter. its
presence in water usually indicates "fresh pollution" of sanitary significance. what
is it?
a. ammonia
b. sugar
c. carbon dioxide
d. hydrogen sulfide -✓✓ammonia
• The presence of which of the following elements in water treatment plant
effluent is used as a measure of filtration efficiency?
a. copper
b. aluminum
c. zinc
,d. lead -✓✓aluminum
• Which of the following is not used to disinfect water?
a. chlorine
b. bromine
c. fluorine
d. iodine -✓✓fluorine
• The presence of which of the following in water would indicate past of possibly
intermittent pollution?
a. streptococcus fecalis
b. escherichia coli
c. clostridium perfringens
d. enterococci -✓✓clostridium perfringens
• Often over 90% of sodium arsenate can be removed by
a. filtration
b. coagulation
c. ion exchange
d. all of the above -✓✓coagulation
• Reduction of the level of fluorides in drinking water can be accomplished by
a. coagulation
b. lime softening
c. ion exchange
d. all of the above -✓✓all of the above
• When collecting bacteriological samples that have been chlorinated, what
chemical is used to chlorinate the water?
a. sodium sulfate
b. sodium thiosulfate
c. sodium bisulfate
,d. sodium bisulfite -✓✓sodium thiosulfate
• Methylene blue active substance (MBAS) is a test to identify
a. hardness of water
b. iron in water
c. presence of detergents containing phosphates
d. presence of coliform in bacteria -✓✓presence of detergents containing
phosphates
• Which organism is not known as an iron bacterium?
a. crenothrix
b. giardia lamblia
c. ferric chloride
d. leptothrix -✓✓giardia lamblia
• The final product in biochemical oxidation of ammonia yields;
a. nitride
b. nitrite
c. nitrate
d. nitrogen -✓✓nitrate
• Which contaminant in water is associated with methemoglobinemia?
a. zinc
b. lead
c. copper
d. nitrate -✓✓nitrate
• The substance constantly used as a coagulant in water treatment is:
a. aluminum sulfate
b. calcium sulfate
c. potassium chloride
d. sodium phosphate -✓✓aluminum sulfate
, • The disinfecting ability of chlorine is affected most by:
a. BOD
b. temperature
c. hydrogen ion concentration
d. dissolved oxygen -✓✓hydrogen ion concentration
• Alkalinity exists in three forms, which is not one of these forms?
a. bicarbonate
b. hydroxide
c. carbonate
d. hypochlorite -✓✓hypochlorite
• Which of the following would not contribute to water hardness?
a. calcium sulfate
b. magnesium sulfate
c. calcium chloride
d. sodium chloride -✓✓sodium chloride
• Improperly located wells, allowing fecal pollution of the water supply may lead
to outbreaks of:
a. botulism, leptospirosis, typhus fever, maria
b. brucellosis, strep infections, chlorea, yellow fever
c. salmonellosis, shigellosis, chlorea, hepatitis
d. relapsing fever, histoplasmosis, psittacosis -✓✓salmonellosis, shigellosis,
chlorea, hepatitis
• Historically in the US, most of the impetus for adequate water treatment came
from the need to control:
a. infectious hepatitis
b. tuberculosis
c. malaria
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• The presence of which of the following is most easily identified by laboratory
analysis in water contaminated by feces?
a. shigella dysenteriae
b. coliform
c. entamoeba histolytica
d. salmonella typhosa -✓✓coliform
• Which of the following disinfecting compounds can be used in full strength for
disinfecting?
a. perchloron
b. calcium hypochlorite
c. chlorinated lime
d. sodium hypochlorite -✓✓sodium hypochlorite
• This substance is the first product of the decomposition of organic matter. its
presence in water usually indicates "fresh pollution" of sanitary significance. what
is it?
a. ammonia
b. sugar
c. carbon dioxide
d. hydrogen sulfide -✓✓ammonia
• The presence of which of the following elements in water treatment plant
effluent is used as a measure of filtration efficiency?
a. copper
b. aluminum
c. zinc
,d. lead -✓✓aluminum
• Which of the following is not used to disinfect water?
a. chlorine
b. bromine
c. fluorine
d. iodine -✓✓fluorine
• The presence of which of the following in water would indicate past of possibly
intermittent pollution?
a. streptococcus fecalis
b. escherichia coli
c. clostridium perfringens
d. enterococci -✓✓clostridium perfringens
• Often over 90% of sodium arsenate can be removed by
a. filtration
b. coagulation
c. ion exchange
d. all of the above -✓✓coagulation
• Reduction of the level of fluorides in drinking water can be accomplished by
a. coagulation
b. lime softening
c. ion exchange
d. all of the above -✓✓all of the above
• When collecting bacteriological samples that have been chlorinated, what
chemical is used to chlorinate the water?
a. sodium sulfate
b. sodium thiosulfate
c. sodium bisulfate
,d. sodium bisulfite -✓✓sodium thiosulfate
• Methylene blue active substance (MBAS) is a test to identify
a. hardness of water
b. iron in water
c. presence of detergents containing phosphates
d. presence of coliform in bacteria -✓✓presence of detergents containing
phosphates
• Which organism is not known as an iron bacterium?
a. crenothrix
b. giardia lamblia
c. ferric chloride
d. leptothrix -✓✓giardia lamblia
• The final product in biochemical oxidation of ammonia yields;
a. nitride
b. nitrite
c. nitrate
d. nitrogen -✓✓nitrate
• Which contaminant in water is associated with methemoglobinemia?
a. zinc
b. lead
c. copper
d. nitrate -✓✓nitrate
• The substance constantly used as a coagulant in water treatment is:
a. aluminum sulfate
b. calcium sulfate
c. potassium chloride
d. sodium phosphate -✓✓aluminum sulfate
, • The disinfecting ability of chlorine is affected most by:
a. BOD
b. temperature
c. hydrogen ion concentration
d. dissolved oxygen -✓✓hydrogen ion concentration
• Alkalinity exists in three forms, which is not one of these forms?
a. bicarbonate
b. hydroxide
c. carbonate
d. hypochlorite -✓✓hypochlorite
• Which of the following would not contribute to water hardness?
a. calcium sulfate
b. magnesium sulfate
c. calcium chloride
d. sodium chloride -✓✓sodium chloride
• Improperly located wells, allowing fecal pollution of the water supply may lead
to outbreaks of:
a. botulism, leptospirosis, typhus fever, maria
b. brucellosis, strep infections, chlorea, yellow fever
c. salmonellosis, shigellosis, chlorea, hepatitis
d. relapsing fever, histoplasmosis, psittacosis -✓✓salmonellosis, shigellosis,
chlorea, hepatitis
• Historically in the US, most of the impetus for adequate water treatment came
from the need to control:
a. infectious hepatitis
b. tuberculosis
c. malaria
