REHS Exam Questions with Complete Solutions | 2024

REHS Exam Questions with Complete Solutions | 2024 Which of the following organisms are most resistant to unfavorable environmental conditions and indicate past of possibly intermittent pollution? a. fecal streptococci b. eschericha coli c. aerobacter aerogenes d. clostridium sporulates - Answer️️ -clostridium sporulates 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 - Answer️️ -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 - Answer️️ -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 - Answer️️ -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 - Answer️️ -aluminum Which of the following is not used to disinfect water? a. chlorine b. bromine c. fluorine d. iodine - Answer️️ -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 - Answer️️ -clostridium perfringens Often over 90% of sodium arsenate can be removed by a. filtration b. coagulation c. ion exchange d. all of the above - Answer️️ -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 - Answer️️ -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 - Answer️️ -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 - Answer️️ -presence of detergents containing phosphates Which organism is not known as an iron bacterium? a. crenothrix b. giardia lamblia c. ferric chloride d. leptothrix - Answer️️ -giardia lamblia The final product in biochemical oxidation of ammonia yields; a. nitride b. nitrite c. nitrate d. nitrogen - Answer️️ -nitrate Which contaminant in water is associated with methemoglobinemia? a. zinc b. lead c. copper d. nitrate - Answer️️ -nitrate The substance constantly used as a coagulant in water treatment is: a. aluminum sulfate b. calcium sulfate c. potassium chloride d. sodium phosphate - Answer️️ -aluminum sulfate The disinfecting ability of chlorine is affected most by: a. BOD b. temperature c. hydrogen ion concentration d. dissolved oxygen - Answer️️ -hydrogen ion concentration Alkalinity exists in three forms, which is not one of these forms? a. bicarbonate b. hydroxide c. carbonate d. hypochlorite - Answer️️ -hypochlorite Which of the following would not contribute to water hardness? a. calcium sulfate b. magnesium sulfate c. calcium chloride d. sodium chloride - Answer️️ -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 - Answer️️ -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 d. typhoid - Answer️️ -typhoid The liquid form of chlorine used for emergency disinfection of small volumes of a. calcium hypochlorite b. sodium hypochlorite c. bromide hypochlorite d. potassium hypochlorite - Answer️️ -sodium hypochlorite The presumptive evidence of the presence of coliform in the MPN test is: a. the color change in the culture media b. turbidity of the culture broth c. the presence of gas from the fermentation of the media d. metallic sheen of colonies - Answer️️ -the presence of gas from the fermentation of the media If hard water is softened by the ion exchange method, which one of the following will increase? a. dissolved oxygen b. iron c. p1-1 d. sodium - Answer️️ -sodium The langelier index is used to determine the point of stability of a. aluminum sulfate b. calcium carbonate c. water pH d. HOCL - Answer️️ -calcium carbonate The manner in which water moves from place to place, changing from one form to another is called the: a. evaporation cycle b. hydrologic cycle c. precipitation cycle d. evapotranspiration cycle - Answer️️ -hydrologic cycle Which of the following is not a characteristic of groundwater? a. most bacteria are absent b. evaporation is virtually non-existent c. it is less expensive to treat than surface water d. it is more expensive to access than surface water - Answer️️ -it is more expensive to access than surface water The amendments of the Safe Drinking Water Act do not cover: a. municipal wells b. county reservoirs c. private wells d. public water systems - Answer️️ -private wells Degradation of groundwater supplied by human-generated pollutants is generally the result of: a. failure to cover the water supply b. failure to adequately chlorinate the water c. faulty waste disposal practices d. allowing industry exceptions to safe water practices - Answer️️ -faulty waste disposal practices The primary reason for the decline in th