Water Treatment Class E Cheat
Sheet Exam Questions and
Answers
The minimum distance that a potable water line has to be from a sewer line.
- -10 Feet
-The minimum distance that a potable water line has to be above a sewer
line - -1 Foot
-Minimum size coupling for a fire hydrant - -6 inches
-How small must a system be in order to be able to collect all TC samples on
one day? - -4900 or fewer served
-How soon must a + TC sample be resampled - -Within 24 hours of the
positive result
-Where must repeat TC tests be sampled - -at the same tap, up and down
at most 5 service connections of the positive result
-What must a positive TC sample be checked for? - -The presence of FC or
EC
-Volume of a TC sample - -100 mL
-What must be done before pulling a distribution sample? - -Disinfect the
sample point by torching or chemicals
-What is the Population Equivalent? - -A 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? - -May 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 - -HxWxL
,-Volume of a cylinder - -pi x radius squared x height
-how do you fill a line with water? - -From the lowest point to the highest
point
-what concentration of Cl2 must be used to disinfect a distribution line or
tank? - -50 ppm
-what is the maximum length of a dead end with a 2 inch line? - -1500 feet
-what is a rotameter and what does it measure? - -a rotameter is a glass
enclosure with a ball inside used to measure the flow of gas from a cylinder
in PPD (pounds per day)
-what must you do when starting a centrifugal pump? - -make sure the
suction side valve is open and that the pump is primed
-What is Chlorine dose? - -The amount of chlorine added to a water supply
-what is chlorine demand? - -the amount of chlorine required to "make the
kill"
-What is chlorine residual? - -The amount of chlorine left over after the kill
-name the processes of a conventional surface water treatment plant - -
Coagulation, flocculation, sedimentation and filtration
-What is the purpose of The Safe Drinking Water Act? - -to protect the public
from waterborne diseases
-Name some waterborne diseases - -Hepatitis, Anthrax, Dysentery, Cholera,
typhoid fever, giardiasis, gastroenteritis, meningitis, polio
-What is the purpose of a transformer? - -Reduce voltage
-Define ampere - -A measure of current strength
-Define voltage - -the electrical pressure available to cause a flow of current
when an electric circuit is closed
-What is a Watt - -a unit of power
-What is an ohm - -a unit of electrical resistance
, -What are the characteristics of potable water? - -Does not contain
objectionable pollution, contamination, minerals or infective agents. Is
considered satisfactory for drinking
-What is the first thing to check when starting a gasoline engine? - -the oil
level / gasoline level
-what is the function of a check valve? - -To allow water to only move in one
direction
-what should the drip rate of the packing gland on a centrifugal pump, which
has rope packing be? - -a drop/second or 60 drops/minute
-name the symbols for these elements:
Iron, Calcium, Lead, Carbon, Hydrogen, arsenic, barium, cadmium,
chromium, mercury, selenium, silver, Fluorine, Nitrogen, chlorine - -Fe, Ca,
Pb, C, H, As, Ba, Cd, Cr, Hg, Se, Ag, F, N, Cl
-What is the function of a gate valve? - -To isolate a section of line.
-What are the two positions of a gate valve? - -All the way open or all the
way closed.
-What is the function of wear rings in pumps? - -To protect the impeller and
wear out before an expensive part has to be replaced.
-Define an aquifer - -A natural, underground layer of porous, water bearing
material, usually capable of yielding a large amount or supply of water.
-What is the top of the zone of saturation called? - -water table
-What determines the number of TC samples that must be collected in a
system? - -The population size.
-Understand TC rule - -This rule was intends to promote routine surveillance
in order to protect customers from Fecal mater and disease causing bacteria.
The TCR also serves to ID potential pathways of contamination. PWS's must
develop a monitoring plan with monthly sampling at each point.
sites must represent the system. TC samples collected regularly throughout
the month (except in ground water systems serving 4,900 or fewer. They
may collect all samples in one day from different sites).
TC+ samples must be tested for EC. EC+ samples must be reported by the
end of day.
-How could a PWS be out of compliance with the Total Coliform Rule (TCR)? -
-(1) when a repeat sample is TC+ or is missed