DDW-2024-012354

Operation and Maintenance
Exam Review
Acronyms
GPM= gallons per minute
MGD= million gallons per day
TTHM= total trihalomethane
PSI= pounds per square inch
NTU= Nephelometric Turbidity Unit
mg/L= milligrams per litre or ppm= parts per
million are the same
TON= Threshold Odor Number for odor in the water. Should be conducted at 60 degrees C
System Monitoring
To Ensure
Drinking Water is
safe monitor for:
Bacteria
Turbidity
Chlorine residual
Sample Bottles
Sampling bottle/bag should
be filled just above the fill
line or about one inch from
top.
Bottles need to be sterilized
by the lab & ready for use
Bottles have Sodium
Thiosulfate in them to
neutralize the chlorine
Bacteriological Sampling
Procedures
Should allow sample tap water to
run several minutes or as long as
necessary to clear service line
Results are meaningless if sample
is contaminated
Sample identification cards need
to filled out completely
Red water could indicate bacteria
or an electro-chemical
phenomenon
Bacteriological Sampling Procedures
If sample is OK, this only indicates that water was safe at point of sample.
Coliform is an indicator of bacteria presence, absence of coliform indicates water is safe
Sample should be transported as soon as possible in a cool container with ice pack.
Routine bactis should be taken at the customer’s tap at various points that represent the entire system
Chain of custody forms need to be filled out
completely
Not smooth nosed
Composite Sample
A series of grab samples
taken from the same
sampling point at different
times and mixed together
Grab samples represent
instantaneous conditions at
the time and location the
sample was taken
Nitrates
Fertilizing lawns and
farms can cause elevated
levels of nitrates
Nitrates cause
Methemoglobinemia
known as “blue baby”
syndrome
Nephelometric Turbidity
Unit (NTU)
The method used to measure
the cloudiness of the water.
The higher the NTU, the dirtier
the water, the greater the
possibility of microbiological
contamination.
Turbidity can mask bacteria
The use of light through water
to measure
Particle Counter
The method used to measure
the cloudiness of the water –
the amount of particles and
the size of particles.
The dirtier the water, the
greater the possibility of
microbiological contamination.
Weirs
Measured from the
crest of the weir to
the horizontal water
surface in the weir
stilling basin
Membrane Filter Test
Analyzes coliform
bacteria colonies
Any positive sample
requires repeats
More than one positive
is a quality violation
GWR
TC+ bacterial Samples
Requires Triggered Source Water sample (TSW)
All sources that were in operation at time of +TC sample
You can email DDW on sources not sampled – not running
Test for fecal coliform
GWR continued
5 additional samples if
first Triggered Source
Water sample is Fecal+
2 or more sources
requires you to submit
new sample site plan
Correct significant
deficiencies within 120
days
New Minimum PSI Standards
Water pressure is
measured in psi
Maintain minimum of 20
psi at all times
20 psi during fire flow
30 psi during peak
instantaneous demand
40 psi during peak day
demand
Sanitary Surveys Performed
By
Executive Secretary shall ensure a sanitary survey is conducted at least every 3 years
Division of Drinking Water
DEQ District Engineers
Local Health Departments
Forest Service Engineers
Utah Rural Water Association staff
Consulting Engineers
Others authorized by Executive
Secretary
Aesthetics
Means attractive or appealing.
With respect to water it means taste,
odor, or coloration of the water.
Things that affect this are extreme
hardness or high total dissolved solids
Effects range from bad smell and poor
taste to causing stains on laundry
and/or fixtures
Hydrogen sulfide causes rotten egg
odors
Water Storage Reservoirs
Provides adequate water to the water system during average and peak demands
Provides adequate pressures throughout the water systems
Must be covered to prevent algae and bacterial growth
Reserve storage
Fire protection
Most susceptible to degradation from external sources
Measured as volume
Screen Sizes
#14 mesh for air vents and air vacuum release valve
Air vac vent pipe above the flood line
#4 mesh for overflow and drain lines
#14 mesh = 14 squares per inch
#4 mesh = 4 squares
per inch
#14
#4
Pressure Tanks
Blow off valves should
be able to discharge at
pumping rate
Frequent on & off cycling
of the booster pump
shows lack of air in tank
& is water logged
Blow off
Reservoir Maintenance
Comprehensive inspections and
cleaning inside of tank should be
done every 3 to 5 years or more
frequently
Repair
Disinfect
Take bacti’s
Inspect Vents- for ice, screen
holes, etc.
Long & short life coatings for
tank interiors
Surface Reservoirs
Most significant reason for
turn over is a change in
surface water temperature
and density
Act as pre-sedimentation
basins
Water is most dense at
39.2 deg F, 4 deg C.
Colder water has more
oxygen
SCBA
Self Contained
Breathing Apparatus
Always use when
around gas leaks &
oxygen deficient
areas
Confined Spaces
Reservoir site entry
Sources- where
chemicals are stored
Vehicles- Keep away from manhole
Vaults- Carbon Monoxide (CO) will settle to the floor.
Minimum oxygen level of
19.5%
Chemical Handling
All chemicals should
be stored according
to the manufacturer’s
specs
Chemical compound
has multiple
chemicals such as
calcium carbonate
Tank Maintenance
Cycling of water (movement) to prevent freezing
Cathodic protection to protect from corrosion
Age of the water in the tank attributed to quality problems cause by low demand or short circuiting
Sandblasting is recommended for preparing interior of tank
Should be sampled for possible water quality changes
Disinfection of Reservoirs
Facility disinfected before it is put on line
Disinfected after cleaning, repair, painting
AWWA C652
Full reservoir – 10 mg/l/ 24 hours
6 hour/24 hour
Spraying interior – 200 mg/l – 30 minute detention time
Fill 5 %/ 50 ppm – 6 hours, then fill rest of tank <2 ppm – 24 hours
At least one bacteriological sample (TC-)
Water Distribution Systems
Leaks get worse
Do a water audit to identify water & revenue losses
Leak surveys should be done during low flows
Cracked mains should be replaced
Pressures can be measured at a fire hydrant or pressure regulating station
Distribution system pressures
20 psi at all times for peak instantaneous flows
Minimum Water main size
8 inch with fire hydrants
Unless you have an engineer signature to buy off on it
4 inch without fire hydrants
Distribution Systems
Water mains
10 Feet horizontal distance from sewer main
Water main and sewer mains must cross at least
18” of separation
Water line is on top
Water & sewer not installed in the same trench.
Anaerobic growth develops in water devoid of
oxygen causing odor problems
Hydraulic adequacy determined by pressure measurements throughout system at various times
Looped to prevent dead ends, quality problems, and better flow
Customer Service Connection
Corporation valve (corp stop) for customer service line shut off
¾” most common customer service connection
Thaw service line with hot
water or warm air
Consider flow rate &
pressure for sizing
New Main Installation
Jacking and Boring is the
most common technique
for the construction of a
pipeline under a heavily
traveled highway or
railway without
disrupting the traffic
New Water Mains
Steps taken to put into service
Pressure and leak test
Flush out debris
Keep pipe clean
Disinfect the pipe – AWWA C651
Take a chlorine residual
Flush highly chlorinated water
Bacteriological Samples –
2 samples taken 24 hours apart. Why?
Special conditions
Keep ends of pipe plugged when unmanned
Pressure Testing New Water Main
Should be done at 50%
higher than normal
operating pressure or 150
psi whichever is larger
Duration 4 Hours
New connections installed
under pressure are called
hot taps
Water Mains
Never shut main valve completely
(may cause a back siphon)
Disinfect with tablets or granular @
25 mg/L for 24 hours
Continuous Feed – 10 mg/L after 24
hours
Fill main with water
Flush out debris
Fill with chlorinated water
Backfilling Mains
Notify other utilities or blue stakes before digging
Soil placed equally on both sides half way up of the pipe in layers hand tamped
Pipe should covered by about 12” of soil
“Well Point” used to dewater trenches
Shallow mains more
susceptible to freezing
Thrust Blocking
Thrust Block - a concrete mass cast in place between a fitting and the undisturbed soil at the side or bottom of the pipe trench.
Purpose is to keep fittings from moving & either coming loose or apart from the force of the water pressure in the pipe.
Thrust anchors – used when thrust blocks cannot be used
Restrained fitting – use of clamps or anchor screws on fittings
Tie rods – used on mechanical joint fittings that a located close together
Block should be centered on thrust force
Thrust Blocks
Should be place behind
the foot of the hydrant
at the flow line
Fire Hydrants
Hydrant bury is the distance below the
ground to the main connection.
Because of increased population growth
and scaling of pipes, hydrant flow tests
should be performed periodically & after
major changes to distribution system
Dropping a weighted string down the
barrel of hydrant to check for water is
called “Stringing”
Nozzles are usually 2.5 and 4.5 inches
Painted different colors to show flow
Hydrant Cap Color Codes
Class Color Water Flow (GPM)
AA Light blue 1500 or more
A Green 1000–1499
B Orange 500–999
C Red Less than 500
Fire Hydrants
Flushing hydrants can stir up silt creating water quality problems
Should be tested for flow with a pitot gauge
Flow tests show quantity of
available water
Should be metered by
contractors to account for water use
Dry Barrel Hydrants
Drain hole drains barrel to
protect from freezing
Partially open drain valve would
cause excessive leakage from
drain hole
Must be tested for leakage with
main valve open & caps on
Use a listening device to check
for leaking valve seat
Operating valve located in the
base of the hydrant
Flush Hydrants
Means hydrant is
flush with a wall or
ground
For areas where
post hydrants are
not suitable
Flushing the System
Dead End Systems
Water Quality Issues
Customer Complaints
Be mindful of
environmental concerns
During periods of low
demand
Flushing Procedure
Notify customers thru billing,
newspaper, or electronic
media of times and places
affected or anything affecting
the condition of their water
Explain Intent Of Flushing
Notify Hospitals, Dialysis
Patients, Restaurants,
Laundromats, & Others That
May Be Affected
Flushing The System
When The System
Has Become
Contaminated
Newly Installed Or
Repaired Mainlines
Flushing Hydrants
Helps remove taste &
odor causing deposits
Helps remove
encrustations that may
restrict flow
Helps remove sand,
rust, & biological
materials that cause
water quality problems
FLUSHING PROCEDURE
Try To Avoid Flooding Traffic
Areas
Open Hydrant Fully For 5 To
10 Minutes To Stir Up Deposits
Don’t let nearby areas drop
below 20 psi to avoid negative
pressures
Record Pertinent Data: Odor,
Water Appearance, Times, &
Places, Etc.
Fire Fighters
Fire fighters can create
negative pressures
Dead end systems
would likely have
inadequate flows for
firemen
Valves
All system valves
should be exercised
annually
Purpose is to isolate
sections of the
system
Gate Valves
Most commonly used valve in distribution system
Gate Valve: Isolation only, should be either all the way open or all the way closed
Cavitation (formation & collapse of bubbles) can occur
Fully open has least amount of head loss from other valves
Can be repacked without taking out of service
Globe Valves
Best for flow control
throttling, & pressure
regulating
Butterfly Valves -
Higher resistance to
flow
Operates easily &
quickly
They cost less than
gate valves
Used for flow control
& isolation
Ball & Plug Valves
Sluice Gate & Sleeve Valves
PRV Valves
Pressure
Sustaining/Reducing:
maintain either upstream or
downstream pressures
depending on the position
of the pilot screw.
Need to be maintained
periodically
Help reduce water hammer
Pressure Reducing Valves
Installed in parallel
to handle high & low
flows
Altitude Valve
A good valve to
regulate tank levels
Altitude valve:
opens when system
psi drops below a
certain pressure and
closes when the
reservoir reaches a
predetermined level.
Pump Control Valves
Allow pumps to be
started & stopped
against a closed valve
Best method to control
water hammer
Check Valves
Keep flows going
one direction
Flow must be
directional with
pump discharge
lines, customer
service lines, and
water treatment
plants
Air Release Valves (air-vacs)
Allow air in & out
Should be placed at high points in the system
Need to be screened & protected from flooding
Relief valve outlet 12”
above ground
Water Hammer
Occurs when a valve is
closed quickly or pump
shuts down and causes
the water pressures to
rise and fall rapidly.
Sounds like some
hammering on pipe.
Can damage pipes,
causing them burst.
System Mapping
Accurate mapping
ensures the operators
can locate the valves
and main lines in case
of a main break or leak
pH
pH: expression that
refers to the basic or
acidic conditions of the
water
pH is measured on a
scale from 0 to 14.
Less than 7 is more
acidic, greater than 7 is
more basic or higher
alkalinity 7 is neutral.
pH
pH and alkalinity tests can be performed to assess the corrosiveness of the water
Alkalinity expressed as Calcium Carbonate
Chlorine lowers the pH & chlorine rate may need to be increased
Water Hardness
Caused mainly by salts of calcium and magnesium, such as bicarbonate, carbonate, sulfate, chloride and nitrate.
Causes formation of soap curds
Deposits show chemical instability
Deposits of scale in boilers & fixtures
Damages in some industrial
processes
Objectionable tastes in water
Langlier Saturation Index (LSI)
Measures corrosiveness of water
LSI (Carrier)Indication
-2.0 to less than -0.5: Serious corrosion or aggressive
-0.5 to less than 0: Slightly corrosion but non-scale forming
LSI = 0.0 Balanced but pitting corrosion possible
0.0 to less than 0.5: Slightly scale forming and corrosive
0.5 to less than 2: Scale forming but non corrosive
Corrosive
Electrochemical phenomenon
Measurements:
Langelier index
Positive number: Deposit
Negative number: Corrosive
Metal coupons used to measure corrosiveness of
water – determined by weight loss of coupon
Adjustments can be accomplished by:
Chemicals which increase or decrease the
depositing, or
Sequester the problem with the use of
polyphosphates
pH/Alkalinity adjustment w/Lime, Sequestering &
Chelation
Alkalinity
A measurement of the water’s capacity to neutralize an acid
Alkalinity is determined by titrating to an end point with a pH meter or the use of the methyl orange test
Use sulfuric acid to perform test
Affects the coagulation process
Insoluble calcium carbonate compounds cause build up of scale
Hardness expressed as mg/L in CaCO3, to be considered soft should be 0 to 50 mg/L
Head Loss
Valves, elbows, pipe
characteristics, etc.
contribute to loss of flows
Pipe roughness coefficient
tests to see if friction losses
are increasing
Bursting strength of pipe
refers to pipe’s ability to
withstand internal forces
Head Loss
Friction head loss: caused by valves, bends, pipe roughness, etc.
Friction headloss is in direct proportion to the increase in the velocity of the water flow
Various factors can slow down the velocity of water.
Alkalinity expressed as Calcium Carbonate
FRICTIONAL HEADLOSS
Energy used up by water movement
Two Conditions that affect head loss:
1. Roughness of the pipe
2. Velocity of the water
. Two Conditions that affect Roughness:
1. Age – Condition
2. Type of pipe Materials
C-Factor
Indicates the smoothness pipe material
The higher the C value, the smoother the pipe.
To calculate measure flow, pipe diameter, distance between two pressure gauges, and the friction losses between the gauges.
3 most common types of plastic pipe are PVC, PE, & ABS
PVC least susceptible to corrosion
C value reduced by tuberculation
PVC has higher C- factor
than concrete
Water Loss
Affected by: leaks,
pressures, efficiency of the
meter maintenance,
attention given to leak
reduction & unauthorized use
of water
Some systems 10% of the
water produced
Other systems not until 20%
Consumer Calls
Persons name, address, & phone
What’s the problem: taste, odor, discolor,etc.
When was problem first noticed?
Duration of problem?
Are neighbors having same problems?
Has it resulted in any illness?
Has Local Health Dept. or DDW been notified?
Can they get a sample in a clean glass?
Cross Connections
Determined by the degree of hazard
Cross connection: a connection between a potable and an unapproved source.
Two Types of Backflow:
Backsiphonage: backflow caused by a negative or below atmospheric pressure in a water system.
Backpressure: when users pressure is higher than the system pressure
Water user is responsible to keep contaminants out of the water system
Flush out debris and trapped air in newly installed assemblies
An effective program helps minimize degradation of the water system
Responsible for most waterborne disease outbreaks
Devices and Assemblies
Keep contaminants out
Air Gap: a physical break between to connections. Minimum of 1” or two times the diameter of the pipe & safest method of backflow prevention
Double Check Assembly: Has two independent internally loaded check valves, 2 shut off valves, & 4 test cocks.
Cross Connections
Reduced Pressure Principle Assembly: For High Hazards, has 2 spring loaded check valves, a relief valve, 4 test cocks, and 2 shut off valves. Relief port can’t be submerged & installed 12” above floor
Pressure Vacuum Breaker: internal check valve, an internal loaded air poppet, 2 shut off valves and 2 test cocks. Not designed for back pressure
Cross Connection
Atmospheric Vacuum
Breakers not designed to protect against back pressure
Prior to the installation of any backflow
prevention assembly or device owner should be advised thermal expansion hazards
Wire to Water Efficiency
The combined efficiency of
the pump and the motor
together. Also called the
over all efficiency.
Water HP/Electrical
HPx100%=over all
efficiency
The amount of energy
required to overcome the
inefficiencies of the pump
and motor
Electric Motors
Upon start up an electric motor will develop a torque to turn the pump shaft and impeller
Torque causes motor to draw a high amperage
Amperage drops once the pump is up to speed.
To change rotation on 3 phase, switch any 2 leads
Transformers step down voltage
Circuit breakers protect from circuit overloads
Digital Multimeters
Ohm meters measure
resistance
Volt meters measure voltage
Amp meters measure current
Tachometer would show
pump speed
Setting should be set to next
highest level of what you
measuring
Lightning Arrestor
Becomes a low resistance
conductor to ground when
the line voltage exceeds a
predetermined amount
Used to protect equipment
from lightning strikes.
No device made to protect
against a direct hit.
Power Sources
Primary Sources- Power
Company
Auxiliary Sources-
Diesel, Natural Gas, &
Gasoline Powered
Generators may be
necessary in an
emergency
Meter Sizing Considerations
Pressure at the service connection
Highest fixture in the building being
served
Any back flow prevention device
A 5/8 inch meter should be tested
every 5 to 10 years.
Meter should not have more than
20 psi of head loss.
One inch and smaller meters
shouldn’t exceed 15 psi of head loss
Small Meter Installation
Meter pit located on public property
Meter pit relatively safe from vehicle & snow removal equipment
Riser pipes should be 1 to 2 inches away from meter box walls
Use of meter yoke
Use jumper cable to protect from electrical shock from piping in the home
Meter Accuracy
Measure water flow
Worn meters will cause the meter to under register, allowing the customer to receive more water than they pay for.
Unaccountable water loss is the term used in determining meter accuracy & leakage
Over time a worn meter will cost the water system revenue.
Formula: Meter Accuracy= (Meter,GPM)(100%)/Volume,GPM
Magnetic Meters
Maintenance calibration
should include flow at
zero flow rate
Compound Meters
For low to intermediate
flows
Occasionally high flows
Positive Displacement Meter
Nutating disk:
nutating means
nodding. When the
water flows the disk
rotates.
Oscillating Piston Meter
Displacement type
Water flows into a
chamber and displaces
piston
Oscillating circular
motion moves meter
Higher head loss than
nutating disk
Velocity Meter & Venturi
Mechanical rotors or
propellers are turned by
velocity of water to measure
flow
Venturi meters measure
differential pressure & have
no moving parts.
Venturi meters are best for
providing uninterrupted flow
Velocity Meter
Iron
Consumer complaints
Can cause stains on laundry & fixtures
Formation of iron bacteria that form slick slimes on pipe walls
Taste and odor problems
Reacts with chlorine increasing use
Can be removed thru aeration, flushing & polyphosphates
Mixed with manganese react with dissolved oxygen forming insoluble compounds
Manganese
Iron mixed with
manganese reacts
with dissolved
oxygen forming
insoluble
compounds
Causes black stains
Electrolysis
Decomposition of material by an outside electric current
Electric current caused by movement of water in the line
Cathodic protection installed to prevent corrosion
Magnesium anodes help prevent galvanic corrosion
Galvanic corrosion caused by connecting dissimilar metals
Metal coupons evaluated for weigh loss
Tanks – Cathodic Protection
Anodes
Ground Water
Water passing thru
porous soil is called
percolation
Water bearing
geological formation
is called an aquifer
Wells
Sanitary seal – prevents contamination from entering
Well casing – pipe placed inside well to keep it open
Grout – mixture of cement, water and sand pumped between the casing & the drilling hole (annulus)
Specific capacity is the well yield in GPM per foot of drawdown
Well Maintenance
Water needs to be
pumped to waste
until it clears up
ACCURATE RECORD KEEPING
Shows decreases in flow and pressures
Insures each piece of equipment receives proper attention to prolong its life
Shows when preventive maintenance or repairs were last performed
Reduces liability to operator & improves customer service
Work orders best way to track system maintenance