CWEA Collection Systems Maintenance
Questions and Answers with Complete
Solutions
Why are gasoline and volatile solvents objectionable when present in a sewer? ✔✔They produce
an explosion hazard
You should never attempt to install, maintain, repair or replace electrical equipment panels,
controls, wiring or circuits unless ✔✔You know what you are doing, are qualified and are
authorized
What are the different areas of traffic zones? ✔✔Advance Warning Area, Transition Area,
Activity Area (buffer space and work space), Termination Area. Could be 4 or 5, justify your
answer on the test!
why should hydrogen sulfide be controlled? ✔✔to protect from corrosion and odors
Personnel entering a Permit Required Confined Space must have the following training ✔✔entry
and rescue
To find protective gear before application of a product, you should: ✔✔look at the MSDS
The gas most commonly associated with septic wastewater is ✔✔Hydrogen Sulfide
The lack of an unpleasant odor in a manhole, lift station or other structures does not always mean
that dangerous gases are not present because: ✔✔some dangerous gasses are odorless (for
example, carbon monoxide)
What are the four conditions necessary to create an explosion? ✔✔combustible gas, adequate
oxygen, heat and proper mixing of gas and oxygen
what does the “transition area” mean in traffic control? ✔✔It moves traffic out of its normal path
what elements should be considered to improve worker safety in High speed Temporary Traffic
control Zones? ✔✔Rerouting traffic around the work site, positioning of law enforcement
officers in the temporary traffic control zone, and work zone training
What key features would you need to address when developing an S.O.P. for a Lift Station
failure? ✔✔Traffic Control Plan, By-Pass connections, and Spill containment
What tools are used with a power rodder? ✔✔Spring Blades
Tools used for sewer rodding include: ✔✔porcupine, root saw, square bar cork screw
What tool would you use to cut VCP pipe? ✔✔Chain Pipe Cutter
Which conditions should a gas detection device test for? ✔✔Hydrogen sulfide,
explosive/flammable gases, oxygen
What does “LEL” mean on a gas detection meter? ✔✔Lower Explosive Limit
The oxygen level alarm normally goes off if oxygen levels are below: ✔✔19.5 percent
When developing an S.O.P. for scheduled maintenance of electrical equipment, what program
should be addressed as a primary safety guideline? ✔✔The L.O.T.O Program
What does L.O.T.O. Stand for? ✔✔Lock out tag out
Cwea collections Grade 1 Already
Passed
Sewer maintenance vehicles are ✔✔difficult to maneuver
At low concentrations, hydrogen sulfide smells like ✔✔Rotten Eggs
which safety hazard in a collection system operations can be detected by an insturment?
✔✔Toxic Gases
What must be checked first before entering a manhole? ✔✔Proper barricades or warning devices
around manhole.
When should field crews use signs and cones? ✔✔When over half the street is blocked.
The different zones of traffic control include ✔✔buffer
Elements of defensive driving include ✔✔having your vehicle under control
CWEA Grade I Laboratory Analyst
Questions and Answers Graded A
Chloride ✔✔- Major anion found in many natural waters
- Can impart salty taste in H2O
What increases concentration of chloride in wastewater ✔✔Chloride in human diet and softeners
flushed into sanitary sewer system
2 most prevalent methods of measuring chloride ✔✔argentometric and mercuric nitrate
Argentometric ✔✔Titration of sample with standard solution of silver nitrate (AgNO3) - Indicator: Chromate ions (CrO4)
- End point: reddish silver chromate
Mercuric Nitrate ✔✔Titration with standard mercuric nitrate solution
-pH must be adjusted between 2.3 and 2.8 - Indicator: Diphenyl carbazone
- End point: Change from blue to purple in presence of mercury
Interference of Mercuric Nitrate Method ✔✔Sulfide, bromide, orthophosphate (over 30 ppm),
and iodide
Why does color change in water ✔✔Presence of decaying vegetable matter, metal ions (ie. iron)
or industrial and domestic pollution
How is color measured ✔✔Measured using visual comparison method
Visual comparison method ✔✔Sample compared to standards using matched nessler tubes
- Standards prepared with solution containing cholorplatinate and cobaltous chloride
Standard units for color ✔✔One unit= color resulting from 1 mg of platinum/L
2 color reporting ✔✔True and Apparent
True color ✔✔Color from dissolved substances, determine using sample treated to remove
turbidity
Apparent Color ✔✔Includes dissolved and suspended solids
Conductivity ✔✔H2Os capability to pass electrical flow
Conductivity of pure water ✔✔0
Units of conductivity ✔✔micromhos/cm
Temperature conductivity should be read at ✔✔25 degrees Celcius
How is conductivity affected ✔✔Mobility of ions, conductivity is dependent on viscosity
Viscosity ✔✔A liquids ability to resist flow, higher the viscosity the lower the flow
Relationship of temperature and viscosity ✔✔Inverse
CWEA E1 Study Set Questions and
Answers 100% Pass
Confined Space ✔✔A space that:
-is large enough to enter and work.
-has limited or restricted means for entry.
-is not designed for continuous occupancy.
Hot Work Permit ✔✔An employer’s written authorization to perform work capable of providing
a source of ignition.
Inerting ✔✔A form of purging or ventilating a confined space where an inert gas (such as
nitrogen, carbon dioxide or argon) is used to displace the atmosphere in a confined space to
remove fire or explosion hazards. Causes oxygen levels to become unstable for re-entry.
Oxygen Safe Zone ✔✔19.5% to 23.5%
Below 19.5=unsafe for breathing
Above 23.5=explosive
Leader Line ✔✔The part or area of a drawing to which a number, note or other reference
applies. They are solid lines and usually terminate in a single arrowhead.
Hydraulic Term:
“Resistance” ✔✔A construction in the bore of the pipe which requires more pressure to pass the
same amount of water.
Hydraulic Term:
“Voltage”
(Assume water is flowing horizontally so gravity isn’t a factor) ✔✔Electric potential is
equivalent to pressure and the voltage (or voltage drop/potential difference) is the difference in
pressure between two points.
Hydraulic Term:
“Current” ✔✔Equivalent to a hydraulic volume flow rate; that is the volumetric quantity of
flowing water over time.
Ohm’s Law ✔✔Current through a conductor between two points is directly proportional to the
voltage across the two points.
S.O.P. ✔✔Standard operating procedure.
N.E.C. ✔✔National Electrical Code.
N.F.P.A. ✔✔National Fire Protection Association
NPT ✔✔National pipe thread. Tapered pipe.
Compound Gauge ✔✔Displays negative AND positive pressure measurements
Cat1 Meter ✔✔Measures electronics
Cat2 Meter ✔✔Measures single-phase receptacles.
Cat3 Meter ✔✔Measures 3 phase distribution and single phase lighting equipment.
CWEA Collections Grade 2 Practice Test
Rated A
Why are gasoline and volatile solvents objectionable when present in a sewer?✔✔ They produce
an explosion hazard
You should never attempt to install, troubleshoot, maintain, repair, or replace electrical
equipment unless:✔✔ You know what you are doing, are qualified, and are authorized.
How many different areas of traffic zones are there when working in roadways?✔✔ Five
Why should hydrogen sulfide be controlled?✔✔ To protect sewers and structures from corrosion
Personnel entering a Permit Required Confined Space must have the following training:✔✔
Entry and rescue procedures
To find proper protective gear before application of a product, you would:✔✔ Look at the
MSDS (Material Safety Data Sheet)
The gas most commonly associated with septic wastewater is:✔✔ Hydrogen Sulfide (H2S)
The lack of an unpleasant odor in a structure does not always mean that dangerous gases are not
present because:✔✔ Some dangerous gases have no odor
What four conditions are necessary to create an explosion?✔✔ Combustible gas, adequate
oxygen, sufficient heat, and proper mixing of gas and oxygen.
What does “transition area” mean in traffic control?✔✔ Moves traffic out of its normal path
The term “transition area” is one component of a:✔✔ Traffic Control Zone
What elements should be considered to improve worker safety in High Speed Temporary Traffic
Control Zones?✔✔ Rerouting traffic around the work site, positioning of law enforcement
officers in the temporary traffic control zone, and work zone training.
What key factors would you need to address when developing an S.O.P. for Lift Station
failure?✔✔ Traffic control plan, by-pass connections, and spill containment.
CWEA Grade 4 Test with Complete
Solutions
AA ✔✔atomic absorption
AC ✔✔power alternating current
ac ✔✔acre
AF ✔✔acre-foot (feet)
AFY ✔✔acre-foot per year
AMSA ✔✔Association of Metropolitan Sewerage
Agencies
ANSI ✔✔American National Standards Institute
APHA ✔✔American Public Health Association
AS ✔✔activated sludge
ASCE ✔✔American Society of Civil Engineers
ASME ✔✔American Society of Mechanical
Engineers
ASTM ✔✔American Society for Testing and
Materials
AWT ✔✔advanced wastewater treatment
AWWA ✔✔American Water Works Association
BECP ✔✔Business Emergency and
Contingency Plan
BNR ✔✔biological nutrient removal
BOD5 ✔✔biochemical oxygen demand after
5 days
BTU ✔✔British thermal unit
C ✔✔Celsius
Cal-OSHA ✔✔California Occupational Safety and
Health Act
Cal-EPA ✔✔California Environmental Protection
Administration
CBOD ✔✔carbonaceous biochemical oxygen
CWEA E/I Level 3 Questions and
Answers 100% Pass
If the potential difference across the coil is low, the coil will:
A-draw too much current
B-become too hot
C-Produce too much magnetic force
D-not heat up ✔✔D-not heat up
The NEC identifies environments that contain flammable vapors and gases as which class of
hazardous location?
A-Class I
B-Class II
C-Class III
D-Class IV ✔✔A-Class I
Which of the following reduces high voltages and currents to save values for measurements?
A-auto transformer
B-megohmmeter
C-instrument transformer
D-variable transformer ✔✔C-instrument transformer
In a three wire control circuit, when a power failure occurs:
A-The interlock contact will close the circuit
B-The operator can restart the meter automatically
C-The motor can restart unexpectedly
D-The operator must restart the meter manually ✔✔D-The operator must restart the meter
manually
Push buttons are classified as standard duty or heavy duty according to the:
A-Kind of enclosure
B-Service conditions
C-frequency operation
D-Current carrying ability ✔✔D-Current carrying ability
He push to test pilot light is used in applications where the pilot light is:
A-rarely needed
B-A neon bulb
C-used in DC applications
D-in constant use ✔✔A-rarely needed
The advantage of LCDs over LEDs is:
A-accuracy
B-better visibility
C-lower power consumption
D-sensitivity ✔✔C-lower power consumption
Shielding protects an analog meter from:
a. damage due to careless handling.
b. harmful UV rays.
c. over-current and surges.
d. stray magnetic fields. ✔✔d. stray magnetic fields.
An ammeter should be connected:
a. across the line.
CWEA Collections System Maintenance
Grade 3 Already Passed
Flagger should Stand?
A. On the shoulder adjacent to traffic being controlled
B. In the closed lane before stopping vehicle traffic
C. In the traffic lane.
D. As stated in “A” or “B” above. ✔✔D. As stated in “A” or “B” above.
Legally responsible officials are required to report category 1 sanitary sewer overflows?
A. Within 30 days
B. Before end of the day
C. As soon as possible
D. Within 2 hours ✔✔D. Within 2 hours
When working in confined spaces or sewers, what form of lighting would you use?
A. Mirrors to direct the sunlight or explosion proof lighting.
B. Ordinary electric lights
C. Propane, Gas, or kerosene lanterns
D. Special matches ✔✔A. Mirrors to direct the sunlight or explosion proof lighting.
What can happen if water-based substances are used to extinguish electrical fires?
a. Nothing but extinguish the fire
b. The fumes are not harmful
c. Receive an electrical shock
d. They will corrode the electrical contacts ✔✔c. Receive an electrical shock
When testing a manhole for explosive gases when should the first tests be made?
a. After removing the manhole cover
b. Before removing the manhole cover
c. At any time
d. After ventilation ✔✔b. Before removing the manhole cover
Atmospheric hazards encountered in manholes can include:
a. non-explosive atmospheres.
b. non-toxic atmosphere.
c. lack of oxygen.
d. non-flammable atmospheres. ✔✔c. lack of oxygen.
When setting up to ventilate a manhole, the air inlet should be how many feet above street level?
a. 4.0
b. 3.0
c. 2.0
d. 1.0 ✔✔c. 2.0
Which chemical may be used for odor control in a sewer system?
a. Calcium chloride
b. Hydrogen peroxide
c. Oxidized aluminum
d. Sodium chloride ✔✔b. Hydrogen peroxide
What information must be on a warning tag attached to a switch that has been locked out?
a. Directions for removing tag.
b. Name of nearest physician to call in case of emergency.
CWEA Collections System Maintenance
Grade 3 Already Passed
Flagger should Stand?
A. On the shoulder adjacent to traffic being controlled
B. In the closed lane before stopping vehicle traffic
C. In the traffic lane.
D. As stated in “A” or “B” above. ✔✔D. As stated in “A” or “B” above.
Legally responsible officials are required to report category 1 sanitary sewer overflows?
A. Within 30 days
B. Before end of the day
C. As soon as possible
D. Within 2 hours ✔✔D. Within 2 hours
When working in confined spaces or sewers, what form of lighting would you use?
A. Mirrors to direct the sunlight or explosion proof lighting.
B. Ordinary electric lights
C. Propane, Gas, or kerosene lanterns
D. Special matches ✔✔A. Mirrors to direct the sunlight or explosion proof lighting.
What can happen if water-based substances are used to extinguish electrical fires?
a. Nothing but extinguish the fire
b. The fumes are not harmful
c. Receive an electrical shock
d. They will corrode the electrical contacts ✔✔c. Receive an electrical shock
When testing a manhole for explosive gases when should the first tests be made?
a. After removing the manhole cover
b. Before removing the manhole cover
c. At any time
d. After ventilation ✔✔b. Before removing the manhole cover
Atmospheric hazards encountered in manholes can include:
a. non-explosive atmospheres.
b. non-toxic atmosphere.
c. lack of oxygen.
d. non-flammable atmospheres. ✔✔c. lack of oxygen.
When setting up to ventilate a manhole, the air inlet should be how many feet above street level?
a. 4.0
b. 3.0
c. 2.0
d. 1.0 ✔✔c. 2.0
Which chemical may be used for odor control in a sewer system?
a. Calcium chloride
b. Hydrogen peroxide
c. Oxidized aluminum
d. Sodium chloride ✔✔b. Hydrogen peroxide
What information must be on a warning tag attached to a switch that has been locked out?
a. Directions for removing tag.
b. Name of nearest physician to call in case of emergency.