"When sampling water for bacteriological analysis, the operator taking the sample should always?","rinse the bottle with the water being sampled.","sterilize the bottle with strong chlorine solution.","filter the sample through a clean filter cloth.","mail sample on Thursday so it will be delivered on Monday.","none of the above.","5"
"When operating a surface water treatment plant, which of the following laboratory tests is of most significance for establishing chemical dosages for coagulating water?","pH and alkalinity.","sulfates.","chlorides.","calcium and magnesium.","total hardness.","1"
"The purpose of the jar test is to determine?","correct amount of coagulant to use for proper coagulation.","amount of CL2 to add for breakpoint chlorination.","proper amount of mixing & settling time to remove turbidity.","length of the flash mix.","","1"
"In a conventional treatment plant using pH adjustment, the minimum number or runs in a jar test is?","1.","2.","3.","4.","","1"
"When making a residual chlorine test (DPD method), the chemical is added to the water to produce what color?","blue.","white.","red.","green.","","3"
"The standard sample for the multiple-tube fermentation method of testing for coliform bacteria consists of?","five 10-mL portions.","two 10-mL portions.","ten 5-mL portions.","ten 10-mL portions.","","1"
"The indicator methyl orange is used in the test for?","total hardness.","alkalinity.","chlorine residual.","pH.","","2"
"The first test used in the multiple-tube fermentation method in the determination of coliform bacteria in water is?","the Completed Test.","the Presumptive Test.","the BOD Test.","the Confirmed Test.","","2"
"Which laboratory test in a water plant is concerned with indicator changes at pH 8.3 and about pH 4.5?","total hardness.","pH.","total chlorine residual.","alkalinity.","","4"
"A step in determining the threshold odor number is?","diluting the sample with distilled water.","matching the odor against the standards.","diluting the sample with odor-free water.","counting the odor-producting organisms present.","","3"
"The amperometric titration method is used to measure?","chlorine residual.","pH.","total hardness.","alkalinity.","","1"
"A sample bottle should hold at least 100 mL and have room for air space above the sample?","true.","false.","","","","1"
"Bottles to be used to collect samples of chlorinated water should contain sodium thiosulfate?","true.","false.","","","","1"
"Copper, aluminum, and stainless steel are approved materials for pipette containers?","true.","false.","","","","2"
"Sterile distilled water should be used for dilution water?","true.","false.","","","","2"
"Sterilization of glassware for 2 hours at 170°C is satisfactory?","true.","false.","","","","1"
"It is necessary to obtain a pure culture of a coliform organism in order to perform a Completed Test?","true.","false.","","","","1"
"A positive presumptive tube identified at the end of 12 hours should preferable be submitted to the Confirmed Test at once?","true.","false.","","","","1"
"Sterile liquid culture media may be stored at room temperature for periods up to 1 week?","true.","false.","","","","1"
"Fecal coliforms can be expected to survive longer that nonfecal coliforms when both are present in a water sample?","true.","false.","","","","2"
"The coliform group includes all of the anaerobic and facultative aerobic gram-positive, nonspore-forming, rod-shaped bacteria that ferment lactose with gas formation within 48 hours at 35°C.","true.","false.","","","","2"
"Incubation of fermentation tubes in the Presumptive Test for the presence of coliform bacteria must be at a temperature of 35± 1.0°C?","true.","false.","","","","2"
"Lauryl tryptose tubes are first examined for the presence of gas at the end of 24± 2 hours?","true.","false.","","","","1"
