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2024 WATER TREATMENT CLASS E CHEAT SHEET EXAM WITH CORRECT ANSWERS
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2024 WATER TREATMENT CLASS E CHEAT SHEET EXAM WITH CORRECT ANSWERS
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2024 WATER TREATMENT CLASS ECHEAT SHEET EXAM WITH
CORRECT ANSWERS
The minimum distance that a potable water line has to be from a sewer line.
- CORRECT-ANSWERS10 Feet
What is conditions are important for coagulation? - CORRECT-
ANSWERSAlkalinity, mixing speed, pH, temp, turbidity
How is alkalinity increased? - CORRECT-ANSWERSThrough the addition of
caustic soda, soda ash, or lime.
Optimal pH range for alum - CORRECT-ANSWERS5.8 - 8.5
Optimal pH range of ferric salts - CORRECT-ANSWERS4 - 11
Coagulants consume ____ as they form salts, causing ____ to drop -
CORRECT-ANSWERSAlkalinity , pH
Water high in color requires lower ____ for optimal coagulation - CORRECT-
ANSWERSpH
Wastes produced during the coagulation process - CORRECT-
ANSWERSResiduals
Describe polymers - CORRECT-ANSWERSVery large particles that carry highly
charged ionic sites
Filter aids - CORRECT-ANSWERSPolymers of different ionic states that are
applied in low doses directly before filtration in order to aid filtration
peristaltic pump - CORRECT-ANSWERSUses a roller to squeeze a tube that
forces liquid through. Used in small volume applications.
A filter must be backwashed when _____________________.
A. Influent NTU decreases
B. Influent pH changes
C. Temperature increases
,D. Head loss across the filter increases and reaches a pre-determined limit -
CORRECT-ANSWERSD. As clogging in the filter increases, the head loss also
increases. Head loss is the resistance to the flow caused by the solids build-
up in the filter. Therefore, you want to clean or backwash the filter when the
head loss reaches a certain point. You don't want the filter to clog
excessively.
Which of the following is a disinfection by-product precursor?
A. Inorganics
B. Arsenic
C. Natural organic matter
D. Nitrate - CORRECT-ANSWERSC.
What is used to regulate iron and manganese?
A. MCL
B. SMCL
C. Revised Total Coliform Rule
D. Lead and Copper Rule - CORRECT-ANSWERSB. They don't pose a health
threat, but they're undesirable because they stain plumbing fixtures.
Specifically, iron causes water to appear red, while manganese leads to
black stains. Therefore, iron and manganese are regulated by non-
mandatory water quality standards called Secondary Maximum Contaminant
Levels (SMCL). An SMCL is not enforceable, and testing for iron and
manganese is voluntary.
Which layer has the most significant temperature change in a stratified lake?
A. Epilimnion
B. Hypolimnion
C. Thermocline
D. Upper layer - CORRECT-ANSWERSC. A lake that is thermally stratified has
3 layers. Most noteworthy, the middle layer has the biggest temperature
decrease with depth. It is called "thermocline" or "metalimnion."
Furthermore, "epilimnion" is the upper warm layer, while "hypolimnion" is
the lower cold layer. The lake remains stratified until early winter, when the
surface water cools, and Lake turnover begins. Consequently, the water
temperature during winter is fairly similar throughout the entire depth.
____________ is the maximum advisable rate of chlorine removal from a 150-
lb gas cylinder.
A. 20 pounds per day
B. 30 pounds per day
C. 40 pounds per day
D. 50 pounds per day - CORRECT-ANSWERSC. If the withdrawal rate is higher
than 40 pounds per day, the cylinder will frost.
, On math questions, always remember to convert to the proper unit. -
CORRECT-ANSWERSif you need the volume in gallons, and you are given
demensions in ft, remember to find the volume using the provided
demensions, which will give you the volume in cubic feet, then convert cubic
feet to gallons (7.48 gal/ft^3). If you are solving for detention time in hours,
use the flow in MGD to find the time in days, then multiply by 24 to get the
time in hours.
The minimum distance that a potable water line has to be above a sewer line
- CORRECT-ANSWERS1 Foot
Minimum size coupling for a fire hydrant - CORRECT-ANSWERS6 inches
How small must a system be in order to be able to collect all TC samples on
one day? - CORRECT-ANSWERS4900 or fewer served
How soon must a + TC sample be resampled - CORRECT-ANSWERSWithin 24
hours of the positive result
Where must repeat TC tests be sampled - CORRECT-ANSWERSat the same
tap, up and down at most 5 service connections of the positive result
What must a positive TC sample be checked for? - CORRECT-ANSWERSThe
presence of FC or EC
Volume of a TC sample - CORRECT-ANSWERS100 mL
What must be done before pulling a distribution sample? - CORRECT-
ANSWERSDisinfect the sample point by torching or chemicals
What is the Population Equivalent? - CORRECT-ANSWERSA means of
expressing the amount of organic material in wastewater. In a domestic
wastewater system, microorganisms use up about 0.2 pound (90 grams) of
oxygen per day for each person using the system (as measured by the
standard BOD test). May also be expressed as flow (100 gallons/person/day
or 378 liters/person/day) or suspended solids (0.2 lb SS/person/day or 90
grams SS/person/day).
How do you calculate the population equivalent? - CORRECT-ANSWERSMay
be expressed as flow (100 gallons/person/day or 378 liters/person/day) or
suspended solids (0.2 lb SS/person/day or 90 grams SS/person/day). Use 2
variables to find the missing variable.
Volume of a rectangle - CORRECT-ANSWERSHxWxL
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