AWWA WSO Water Treatment Grade 2 Textbook - Chapter Study Questions with Correct Answers
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AWWA WSO Water Treatment Grade 2 Textbook - Chapter Study Questions with Correct Answers
Molarity is the number of
moles of solute per liter of solution
3 multiple choice options
CaCO3 is the _____ of calcium carbonate.
chemical formula
3 multiple choice options
The first step in...
AWWA WSO Water Treatment Grade 2
Textbook - Chapter Study Questions
with Correct Answers
Molarity is the number of - answer moles of solute per liter of solution
CaCO3 is the _____ of calcium carbonate. - answer chemical formula
The first step in calculating percent by weight of an element in a compound is to
determine the - answer molecular weight
What term refers to the number of equivalent weights of solute per liter of solution? -
answer normality
A solution consists of two parts: a solvent and a - answer solute
The chemical formula for calcium hydroxide (lime) is Ca(OH)2. Determine the number of
atoms of each element in a molecule of the compound. - answerCa; 1 atoms O; 2 atoms
H; 2 atoms
The equation of the reaction between calcium carbonate (CaCO3) and carbonic acid
(H2CO3) is shown. If 10 lb of H2CO3 is used in the reaction, how many pounds of
CaCO3 will react with the H2CO3? - answer16.1 lb of CaCO3
You need to prepare 25 gal of a solution with 2. percent strength. Assume the solution
will have the same density as water: 8.34 lb/gal. How many pounds of chemical will you
need to dissolve in the water? - answer5.21 lb of chemical
How much water should be added to 80 ml of a 2.5N solution of H2CO3 to obtain a
1.8N solution of H2CO3? - answer31.11 mL
How many atoms of oxygen are present in Ca(HCO3)2? - answer6
Find the detention time in hours for a clarifier that has an inner diameter of 112.2 ft and
a water depth of 10.33 ft if the flow rate is 7.26 mgd. - answer2.52 hr
A chemical metering pump is pumping 26.3 gal/day. How many mL/min is this? -
answer69.1 mL/min
A water treatment plant has an emergency shutdown. How many water supply hours
are left in a 119.8-ft diameter tank given the following data?
,Tank's water level = 27.6 ft
Water cannot go below 16.0 ft at any time to comply with fire control
Water usage averages 483 gmp - answer33.7 hr
How many lb/day of sodium fluorosilicate (Na2SiF6) is required given the following
parameters?
Flow rate is 1,750 gpm.
Fluoride desired is 1.20 mg/L
Fluoride in raw water is 0.15 mg/L
Sodium fluorosilicate is 98.1% pure.
Fluoride (F) ion percent is 60.6% - answer37 lb/day, F
A filter is 24 ft by 28 ft. Calculate the filtration rate in gpm, if it receives a flow of 3,250
gpm. - answer4.8 gpm/ft2
Pressure measured in terms of the height of water (in meters or feet) is referred to as -
answerhead
In the equation to convert milligrams-per-liter concentration to pounds per day, (dosage)
(flow rate)(conversion factor) = - answerfeed rate
In the volume formula, how is volume calculated? - answerarea of surface x third
dimension
What is the formula for calculating the area of a circle? - answer(.785)(D2)
If a spherical tank is 20 ft in diameter, what is its capacity? - answer4,187 ft3
Water being served to the public for a population greater than 3,300 must not have a
disinfectant residual entering the distribution system below ___ for more than 4 hours. -
answer0.2 mg/L
What is the action level for copper? - answer1.3 mg/L
Where are the sampling point(s) located for required sampling of turbidity in a
community water system? - answerAt the point(s) where water enters the distribution
system, including all filter effluents of a surface water treatment plant.
Under the Surface Water Treatment Rule, disinfection residuals must be collected at the
same location in the distribution system as - answercoliform samples
What is the MCL for haloacetic acids (HAA5)? - answer0.060 mg/L
An example of _____ is determining the lowest monthly average during 12-month
monitoring of Giardia and virus inactivation. - answerbenchmarking
, What is the MCLG for substances that are suspected carcinogens? - answerZero
Which regulation is designed to limit human exposure to harmful organisms, including
Cryptosporidium, by promoting achievement of particle and turbidity removal targets for
surface water treatment systems? - answerIESWTR (Interim Enhanced Surface Water
Treatment Rule)
Which regulation is designed to reduce the risk of exposure to fecal contamination that
may be present in public water systems that use ground-water sources? - answerGWR
(Ground Water Rule)
Which regulation is designed to promote routine surveillance of distribution system
water quality to search for contamination from fecal matter and/or disease causing
bacteria? - answerTCR (Total Coliform Rule)
What is the optimal pH range for the removal of particulate matter when using alum as a
coagulant? - answer6.5 to 7.2
Which forces will pull particles together once they have been destabilized in the
coagulation-flocculation process? - answervan der Walls forces
Which of the following is a common mistake that operators make in regards to
flocculation units? - answerAllowing excessive flocculation time
Ferric sulfate has which advantage over aluminum sulfate (alum)? - answerMore dense
floc
The lower the _____, the more difficult it is to form a proper floc. - answerturbidity
Jar test results are expressed in - answermilligrams per liter
List four characteristics of raw water that must be considered in selecting a treatment
chemical. - answerAny four of the following; type and concentration of contaminants,
temperature, alkalinity, pH, turbidity, color, total organic carbon.
Raw-water temperature that approaches the freezing point has what effect on
coagulation and flocculation processes? - answerAs the water temperature decreases,
the viscosity of the water increases (denser), which slows the rate of floc settling.
How much time is required to develop heavy floc particles during the flocculation
process? - answer30 minutes
If enteric disease-causing protozoans have been found in the effluent of a water plant
which is the most probable solution? - answerUse a multibarrier approach--coagulation,
flocculation, sedimentation, and filtration
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