Extra CSI Review

Module 7: Pumps And Motors

• Hydraulics studies liquids under pressure or in motion
• Water pressure represents force exerted on a unit area of water
• A cubic foot of water exerts a pressure of 62.4 psi
• Water pressure is measured in cubic feet per minute or gallons per minute
• A closed valve on a 6-inch waterline under 60 psi has a force of almost 1,700 pounds against it
• Water hammer can move a pipe bend or blow a fitting off
• Hydrostatic head is not lost over distance
• Water velocity decreases over distance
• Higher water velocity leads to lower pressure against the pipe wall
• Velocity head, measured in psi, is the pressure pushing water
• Friction losses in a waterline depend on flow velocity, pipe diameter, pipe length, C-factor, type, and number of fittings
• Higher C-factor correlates to a shorter pipe
• PVC pipe has a higher C-factor than any other non-plastic pipe
• Hydraulic grade line indicates the levels water would rise to in vented stand pipes
• Hydraulic grade line slopes upward in the direction of flow
• Two basic types of pumps are the centrifuge pump and the positive placement pump
• The positive displacement pump is not the most widely used pump in the distribution system
• Pump capacity is quantity of water delivered in a given time under specific conditions
• The water pressure against which pumps operate, measured in psi, is "head”
• "Suction head” exists when the water supply is below the pump centerline, representing the vertical distance (in feet) between the centerline and top of the water supply
• "Suction lift” exists when the water supply is above the pump centerline, representing the same vertical distance in feet
• “Total static head” is the vertical distance (in feet) from the top of water supply to the top of the water level on the pump's discharge side or point of free discharge
• “Total dynamic head” is the total static head plus friction head
• Under suction head conditions, total static head = discharge head + suction head
• A centrifugal pump casing may or may not be a volute, depending on the design
• The center of an impeller is called the impeller eye
• Most impellers moving clean water are open
• The shaft transmits torque from the driver to the impeller
• A shaft sleeve protects the shaft from packing and mechanical seal wear
• Bearings must withstand horizontal (radial) and vertical (longitudinal) forces
• The stuffing box holds the packing or mechanical seal
• A centrifugal pump volute increases liquid velocity, converting pressure head to velocity head
• Water in a single suction pump enters the impeller from one side
• A multistage acts in series, which increases the discharge pressure
• The volume of water pumped by a multi-stage pump is limited to the capacity of the last impeller
• Pump diffusers do not use rotating guide vanes surrounding the impeller
• One diffuser pump type is a vertical turbine “can” pump used as a distribution booster pump
• Check pump and motor shaft alignment periodically to prevent premature bearing and coupling wear
• The primary cause of bearing failure is due to a lack of lubrication
• Packing controls leakage around the pump shaft, not the wear ring
• Overtightening packing causes harm
• Contact between mechanical seal surfaces is maintained by an O-ring
• Replace a mechanical seal when leakage exceeds the manufacturer's criteria
• A high service pump station is an example of a parallel pump installation
• GPM of pumps in series does not equal the GPM of any single pump in the series
• Cavitation involves the collapse of water vapor bubbles on the impeller or inside the pump case
• Cavitation results in pitting, pump vibration, heat, efficiency loss, and noise
• Positive displacement pumps use reciprocating or rotary actions to draw water into the pump
• A positive displacement pump may dewater a trench, but it's rarely used for distribution systems
• Pump selection considerations include pumping capacity, head conditions, and the usage pattern
• Centrifugal pumps have higher GPM, uniform pressure, and increased GPM with a decrease in head compared to positive displacement pumps

Motors

• Electrical motor efficiency typically ranges from 75% to 90%
• Hertz indicates the power generator frequency in cycles per second
• A volt represents the current flow of 1 ampere through 1 ohm
• An ampere is the electron flow of 1 volt/ohm
• The model/code number condenses nameplate data for reference
• The serial number tracks the exact unit
• The standard maximum ambient temperature for a motor is 40°C
• Motor bearings are indicated by LS (Load Side) and OS (Opposite Side)
• Three-phase motor with 4 poles has 12 poles per phase
• Slip is the term for the difference in speed between rotor and stator magnetic fields
• Inspect open/closed motors designs more often than other designs types
• Regularly monitor the operating temperature of motors, and record insulation resistance when the motor it hot
• The rotor of a synchronous motor turns at 60 Hz in the US, matching the power plant generator
• When rotor and stator field reach about 95% synchronous speed with a DC current, they magnetically lock
• Despite the stator field and rotor turning at the same speed, they are not exactly aligned/torque
• Gradual stator/misalignment on a separate foundation needs checking
• Synchronous motor maintenance includes frequent pole/windings cleaning and slip ring inspection
• Internal combustion engines can power pump drivers, backup generators, and portable pumps, starting automatically upon power loss
• A base resting on concrete at a few points can sag, warp, or vibrate since all listed can occur
• Grout/steelwork/concrete act as base anchors and sole plates

Module 8: Water Meters

• The magnetic drive allows the register to be sealed, protecting it from moisture, sand, or minerals
• A piston or disk positive displacement meter wears rapidly at high flow rates
• Water enters a multi-jet meter's measuring chamber through and exits through several openings
• The multi-jet meter cannot pass sand or foreign matter better than the positive displacement meter since it contains a different design
• Proportional meters are for fire service due to their very high head loss
• The venturi meter does not look like an hourglass lying horizontally
• Water velocity increases as it passes through the venturi throat, the water velocity decreases and the water pressure increases
• A pitot tube is a tube with a short 45° bend used to measure water velocity
• To measure flow in a pipe, a pitot tube can be inserted through a curb stop
• Air bubbles in hoses can cause false pitot tube readings, therfore false readings may occur if there no air bubbles
• Magnetic meters produce magnetic field perpendicular to the flow and through a straight pipe, and not a pipe bend
• Acoustic meters use sound waves to measure open water channel or pipe flow
• Transmissive acoustic meters use sound wave pressure, while doppler acoustic meters use sound wave frequency
• Acoustic meters use less power than magnetic meters, but they are less accurate when use with plastic pipe
• Magnetic/synchronism separation occurs when the magnet loses contact with the register
• Turbine/multi-jet meters are best for sustained, high flow with proper design
• Meter life is influenced by usage and water quality
• Meters are field tested with portable test kits, meter shop equipment or a volumetric container
• Test oldest/most meters first, budget to repair/replace
• Depending on the AMR system, water providers can review usage records, profile daily usage, monitor watering days, verify flushing to the wastewater system, and notify a customer when normal usage changes

Module 9: Water Distribution

• It is important for water utility operators to understand the water line construction process, because water systems can fail if improperly installed
• Water line construction encompasses construction plans, excavation, backfilling, pressure testing, as well as turbidity sampling
• Construction plans must be prepared by a licensed operator if requested by the TCEQ
• Preliminary surveys determine service area, route, and financing
• Manholes are not required on each side of the crossing, instead pipe encasements can be utilized
• An easement is a legal right to use a property for utility purposes, while a right-of-way is owned, easements do not transfer ownership
• An easement grants a legal right to build and maintain on property, it includes access rights
• Rights-of-way and easements should be recorded in county deed records
• Material and construction procedures must follow AWWA or ASTM standards as required by the TCEQ
• The TCEQ requires that new water mains must maintain a minimum diameter of 6 inches
• All dead-end mains must have fire hydrants
• There are approved alternatives to the water/wastewater separation rule if necessary
• Water and wastewater lines laid parallel must be in separate trenches
• Warn the public before construction
• Inspect delivered material before acceptance
• Avoid damaging lined and coated pipe protection
• Follow manufacturer's recommendations when stacking pipe
• Photograph private property near the work site
• The trench spoil toe should be at least 2 feet from the trench edge
• Have a trained person inspect shoring weekly
• Do not remove shoring driven into the pipe zone
• Sloping stabilizes trench walls, and benching cuts trenches into stair steps
• "Angle of repose” is the current term for maximum allowable slope
• Type “B” soil is the most common, with a 2:1 maximum slope
• Previously disturbed soil is type “B”
• The water line top must be below the frost line and at least 12 inches underground
• Proper bedding and backfill elevates the bearing strength of a pipe by 50%
• Hydrostatic leakage testing on new mains must meet AWWA standards

Module 10: Operation of the Distribution System

• An operating company must provide its plan to the PWS it services
• Four monitoring locations within public water systems are the raw supply water location, inside the treatment plant, the distribution system entry point, and the distribution system itself
• The TCEQ must be notified of sample site changes because sample sites must be updated
• The TCEQ might reduce sampling frequency at low DBP levels
• The TCEQ ships sample bottles for lead and copper monitoring when due
• Addresses where PWS collects lead and copper samples require TCEQ approval
• A new PWS must contact the TCEQ to initiate lead and copper monitoring
• Like corrosive water, A/C pipe can leach asbestos
• Systems detecting asbestos fibers are monitored yearly if MCL is exceeded, otherwise once every three years
• Sampling may continue even if monitoring shows system water is constantly below the MCL
• Bacteria vital for life are not called pathogens, as those make you sick
• Waterborne diseases include giardiasis, cryptosporidiosis, hepatitis A, and polio
• Coliform bacteria signals fecal contamination
• Fecal coliform is typically found in animal and human waste
• Coliform bacteria generally does not cause health effects, certain E. coli strains can cause mild effects
• Fecal coliform or E. coli indicates intestinal waste and possibly a waterborne disease
• Each coliform sample site needs a letter/number on the system map, the street address or the site location, the site's water main length, and the pressure plane or pump station serving the site
• After flushing the faucet and recording the chlorine residual, sanitize the faucet by swabbing it with a 50/50 alcohol/water mixture
• A TCEQ-approved laboratory must receive the sample within 30 hours
• Samples must remain cool, or on ice, in route to the the designated laboratory for testing
• Positive routine samples prompt PWS to take repeat samples within 12 hours and be collected the same day
• Systems with one sample per month shall take at least four repeat samples for the positive sample, single service systems collect daily repeat samples until its reached
• Repeat sample are taken at that contaminated point
• An MCL violation prompts the PWS to identify the contamination source, fix the issue, and collect "Special" labeled samples ensuring compliance
• The MCL violation is non-acute if a repeat sample is positive for fecal coliform or E. coli or a total coliform repeat sample follows fecal or E. coli routine, some violations include the acute MCL outbreak and initial total coliform
• Public notices must be legible, comprehensible, and effective
• Public notices must detail potential harm
• Public notices must tell which populations are at most risk given contaminants
• Public notice must state which sources of water should be used as alternatives, and what actions to take
• Public notices must be multicolored for prominence
• Backflow from backpressure/siphonage causes cross-connections
• Backpressure/downstream results from increased pressure source
• Siphonage/vacuum stems from a formed vacuum
• PWS must have a backflow prevention device at a residence/business with actual/potential contamination risks
• Backflow prevention on the service line is not required if an adequate internal cross-connection control program is in place at the a PWS residence/business with hazard
• TCEQ does not require service connection backflow prevention if no hazard exists
• PWSs can enforce additional protection through codes/ordinances for cross-connection
• Backflow prevention devices at connections does not nullifies internal hazards protection for buildings
• TCEQ does not approve backflow prevention devices but recognizes all devices, therefore atmospheric vacuum breakers, double check valve devices, pressure vacuum breakers, and reduced-pressure principle devices are used
• Atmospheric vacuum breakers can protect against nuisance substances that pose no health hazards
• Pressure vacuum breakers are vacuum breakers that sustain pressure.
• Health hazards must be tested frequently, therefore assemblies protecting health hazards must be tested and certified annually
• Trained and licensed assembly testers should test and record documentation for at least three years
• Stability denotes corrosive or scaling water traits
• Unstable water causes decreased output, red water, mottled teeth, and pipe deterioration
• Scaling and corrosive water is judged using: calcium carbonate saturation tests, bayliss curve, and langelier saturation index
• Alkalinity refers to the water's bicarbonate, carbonate, and hydroxide content
• Bayliss Curve requires pH measurement and alkalinity determination
• The Langelier Saturation Index uses water temperature, total dissolved solids, calcium, and alkalinity measurements
• The calcium carbonate saturation test measures corrosiveness via water temperature, pH, and amount of calcium carbonate dissolved
• Chemical treatment involves adding alkalinity, scale, and corrosion inhibitors to water
• Tuberculation or mineral scale accumulation results in main flow rates, water pressure decreases, pumping costs and chlorine demand increase
• The cleaning needed for water mains is dependent on pipe diameter, material, water detention and the waters characteristics
• Poly-pigging, high-pressure jetting, chemical cleaning, and electrolysis techniques can be employed for pipe cleaning.
• Unidirectional Flushing (UDF) is the most effective method for cleaning pipes
• Conventional flushing increases coliform samples, the flow of water is lower, there are short benefits, there is greater water loss and the water bills increase with the lack of effectiveness
• Ideally, flushing late-night/early-morning hours uses high pressure with low traffic with residents in mind minimize the effect on people
• Avoid flushing mains larger than 24 inches
• A recommended minimum water velocity is 5/20 feet per second
• Unexplained water loss should not be more that 20/10 %
• Unmetered water usage occurs when the water or wastewater is treated, when there are police and fire departments, or when it is a Public park or golf course, basically, all listed
• Thermography studies help provide more insight to water leaks
• Dechlorinate water to eliminate damage that highly chlorinated discharges may cause
• Disinfectant residual/bacteriological aspects should always be checked after flushing to see if it's safe
• Use shoring 5 feet deep when repairing leaks
• A plan and profile map displays pipe depth, reference points, and utilities
• Chemical analysis, customer service inspection reports should be kept for typically 10 years
• Dead-end main flushing and storage tank cleaning dates should be recorded for at least two years
• Water storage and pressure maintenance facility inspection data should be stored five years
• Studies, pilot projects, and special monitoring data need to be kept permanently
• Chlorine taste and odor results when readings are below 0.2/4.0 mg/L
• Protecting physical areas, increasing security, and strengthening the warning system are the top three vulnerability recommendations