Ohio Rural Water practice questions for Water Supply Class 1
What is a possible cause of a back siphonage condition in a water line?
A leak in the water line
The Chlorine dosage minus the Chlorine demand equals what?
Total chlorine residual
What are four characteristics of a pump curve?
Capacity (gpm), total dynamic head, brake horsepower, pump efficiency
What is the log removal or inactivation required for viruses?
Most colloidal material from the raw water should be removed by what- method in a properly designed and operated treatment plant?
Which is the most likely to occur if the finished water pH is too high?
Scaling in mains
At what temperature does water achieve the greatest density?
4 degrees C
"The process wherein electrostatic forces cause a chemical bridging of enmeshment of colloidal particles into discrete, visible, suspended particle that will readily settle under the influence of gravity", best describes:
After rehabilitation, a pipeline segment should be disinfected, flushed, and:
Tested for bacteria
The main sources of hardness in water are:
Calcium and magnesium
Noncarbonate hardness equals:
Total hardness minus total alkalinity
What can interfere with the chlorine residual in the distribution system?
Turbidity, temperature of water, organics, ammonia
Which of the following violations for the National Interim Primary Drinking Water Regulations require public notification?
Failure to monitor
Failure to comply with an approved test procedure
Which chemical is commonly used to remove noncarbonate hardness?
What should be done if greater than 3% of total water production is used for filter backwashing?
Improve filter influent water quality
Which is the approved method for chlorine testing?
What type of meter measures turbidity?
Which gas increases during aeration?
When placing a new main in service, what is the last test performed?
What chemical is used for recarbonation?
In an ion exchange system, what is the purpose of the rinse cycle?
Remove unused salt
At what temperature will the fusible plugs in a chlorine cylinder melt?
71 to 74 degrees C
How many samples must be collected after a positive coliform test?
One use of polyphosphate in water treatment is:
Keeps iron and manganese in solution
As the temperature of the water is decreased, what will occur?
Viscosity will increase, CaOH solubility will increase
What problem would likely occur if a well screen were not properly gravel packed?
A 5 ml water sample showed 43 colonies. What is the reported value?
860 colonies/100 ml
What is the recommended free chlorine residual for the farthest point in the distribution system?
Which of the following conditions can improper backwashing cause?
Mudball formation and/or gravel displacement
The primary function of a clarifier is:
Permit floc to settle
Which bacteria are used as an indicator in water testing?
Which valve should be used to slowly refill a dry rapid sand filter?
As a pump moves water from the clearwell to elevated storage, the level in the clearwell drops 8 feet. What happens to the pump head?
Increases by 8 feet
What would the operator expect to see if the lime dosage is twice what is required for softening?
Incrustation will increase
Which of the following chlorine chemicals is not used for disinfection?
The primary function of a flocculator is:
What is the most common type of valve used in water distribution systems?
Which one of the following causes black staining?
What is the MCL for Nitrate-Nitrogen in drinking water?
Double the required alum dosage will result in what?
Lowering the pH
What is the effect of slow flocculator tip speed?
If a system has a regular bacteria sample show total coliform positive, what must be done within 24 hours?
Collect repeat samples
"The addition of a chemical to a colloidal dispersion resulting in particle destabilization by a reduction of the forces tending to deep the particles apart" best describes:
The main function of a rapid sand filter is:
Which of the following is the most effective disinfectant?
Free available chlorine
The term for the pressure against which a pump must operate is:
What is the optimum fluoride level for finished water in Ohio?
Which is not used for softening?
Where should potassium permanganate, KMnO4, be applied?
Where is the best location to store a self contained breathin apparatus?