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Drinking Water Operator Certification Review

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Vocabulary

►Aerobic A condition in which atmospheric or dissolved

molecular oxygen is present in the aquatic (water) environment

►Anaerobic A condition in which atmospheric or dissolved

molecular oxygen is NOT present in water

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Vocabulary

►Culinary Fit for human consumption

► Potable Water that does not contain objectionable pollution,

contamination, minerals, or infective agents and satisfactory to drink

► Palatable Water that is pleasing to the senses (desirable temp.,

free from objectionable tastes, odors, colors, & turbidity)

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Vocabulary

►Aesthetics Attractive or appealing

►Taste, odor, or color

Things that affect the aesthetics of water: ►Extreme hardness ►High total dissolved solids

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Terminology

► GPM Gallons per minute (gal/min)

► MGD Million gallons per day (M gal/day)

► TTHM Total trihoalomethne

► PSI Pounds per square inch (lbs/in2)

► mg/L Milligrams per liter (ppm = parts per million)

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Terminology

►MCL = ►NTU = The cloudy appearance of water caused by the

presence of suspended and colloidal matter A turbidity measurement is used to indicate the

clarity of water A nephelometer measures particle-reflected light at

a 90o angle

Maximum Contaminate Level

Nephelometric Turbidity Units

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Terminology

► Electrolysis Decomposition of material by an outside electric current

►Current is created by the movement of water in a pipe

Question: How do you protect your system from electrolysis? Answer: Install Cathodic Protection

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Terminology

►Water Hardness A characteristic of water caused mainly by salts of

calcium and magnesium, such as bicarbonate, carbonate, sulfate, chloride and nitrate

Causes formation of soap curds Increases use of soap Deposits of scale in boilers and fixtures Damages some industrial processes Causes objectionable tastes in water

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Terminology

►pH An expression of the intensity of the basic or

acidic condition of a liquid pH scale 0 to 14

►7 is neutral ►pH greater than 7 is considered basic ►pH less than 7 is considered acidic

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Rules and Regs Review

Name of Contaminant MCL Comments

Fluoride 4 mg/L Field test = SPADNS

TTHMs 80 ppb For SW systems serving a population of 10,000 or greater

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Rules and Regs Review

Name of Contaminant MCL Comments

Copper Action Limit 1.3 ppm or 1300 ppb

• Measured at the tap • Must be met in 90% of

samples • If exceeded must provide

corrosion control treatment and public education

Lead Action Limit 0.015 ppm or 15 ppb

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Rules and Regs Review

Question: A public water system has a least ___

service connections and/or serves at least ___ people for ___ days out of the year?

Answer: 15, 25, 60

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Rules and Regs Review

Question: What is the maximum turbidity levels

for surface water systems? Answer: Never exceed 1.0 NTU, and 95% of samples must be below 0.3 NTU

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Rules and Regs Review

►Microbiological Contaminants: Total Coliform Rule (Total Coliforms, Fecal Coliforms, and E. Coli) Less than 40 samples per month;

►no more than one positive for total coliforms If 40 samples or more per month;

► no more than 5% positive

Note: The total number and location of samples is based upon the population served and a system-specific sampling plan

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Pump Review

►Stuffing Box Contains: Packing or mechanical seal

►Controls leakage ►Mechanical seals are used for high discharge head

Lantern ring ►Allows water to flow evenly

through the packing

Packing glands

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Pump Review Question: Do bowls add volume

or pressure? Answer: Pressure Multi-stage – Stages

add pressure not volume

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Pump Review Question: What is considered to be the heart of the

pump? Answer: The impeller Remember: Water is thrown away from the impeller,

not cupped

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Pump Review

►Couplings Connect shafts of different diameters Transfer energy Allow for sight misalignment Absorb starting torque

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Pump Review

►Pump/Motor Maintenance Follow manufacturers recommendations Avoid over greasing

►Grease acts like an insulator, holding in heat

Most common motor speeds ►1800 rpm ►3600 rpm

Oil Drip rate ►5 drops/min.

Pump Review

► Piping Eccentric reducer

►Suction side

Concentric increaser ►Discharge side

►Cavitation Sounds like pumping rocks, caused by air entrapped

in volute case, air implodes causing damage to pump

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Safety Review

Question: What are the different types of soil and

which one is the most unsafe? Answer: A, B, and C A is the most stable (safest) and C is the

most unstable soil (most unsafe)

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Safety Review

Question: In a trench or excavation, means of egress

is required when? Answer: When a trench is 4 feet or more in depth Exits must be provided at least every 25 feet Ladders must extend 36 inches above the

trench

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Safety Review

Question: What is the minimum distance spoil and

other equipment must be placed from the edge of the trench or excavation?

Answer: Two feet

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Safety Review

► Flag Person Placed a minimum of 100 feet in front of work

site Trained and certification card

►Oxygen Deficient Atmosphere 19.5 percent

►MSDS Holds information regarding hazardous

substances

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Safety Review

►Chemical Safety For acid solutions pour acid into water To neutralize acid spills use Sodium Bicarbonate

(Baking Soda)

►Laboratory Safety Never pipet liquids with your mouth, use a

rubber suction bulb Use PPE

►Safety glasses, rubber gloves, apron, ect.

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Safety Review

►Chlorine Safety Repair Kits

►Kit A is for 150 lb. Cylinders ►Kit B is for Ton Containers

Leaks ►Most occur at the valve ►Can cause greenish or reddish color pipe ►Use ammonia solution to check for leaks

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Security Review

Question: Why are vulnerability assessments conducted? Answer: Identify threats to the water system Determine the likelihood that a threat may

materialize Calculate the consequences of losing part or all

of the water systems assets

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Security Review

Question: What are the three stages of threat

management? Answer: Possible Credible Confirmatory

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Security Review

►Some of the critical components of a water system include the systems water sources treatment plants distribution system communications power sources

NOTE: System inspections should be conducted frequently and randomly

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Security Review

To have an effective ERP, it must address

four important phases:

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O&M Review

►Water Hammer A condition that occurs when a valve is rapidly

closed or opened ►Causes the pressure to increase and decrease back

and forth very quickly

Sounds like someone hammering on a pipe Can damage pipes, causing them to burst or

come apart

O&M Review ►Thrust Blocking Concrete mass

between a fitting and the soil

Keep fittings from moving and coming loose or apart from the force of the water pressure in the pipe

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O&M Review

►Head Loss Friction from various factors can slow down the

velocity of water Can be caused by valves, bends, pipe

roughness (C-Factor), etc.

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O&M Review

►C-Factor A factor or value to indicate the smoothness of

a pipe The higher the C value, the smoother the pipe To calculate measure the flow, pipe diameter,

distance between two pressure gauges, and the friction losses between the gauges

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O&M Review

►Cross Connections Any (actual or potential) connection between a

potable and an unapproved source The problem with a cross connection is that

backflow can occur ►Backflow is the flow of any water, foreign liquids,

gases, or other substances back into a potable water system

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O&M Review

►Two conditions that can cause backflow are: Back Pressure

►A condition in which a pump, elevated tank, boiler, or other means result in a pressure greater than the supply pressure

Backsiphonage ►A condition in which the pressure in the distribution

system is less than atmospheric pressure

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O&M Review

Question: What is the best protection against cross

connection? Answer: Air Gap An open vertical drop, or vertical empty space, that

separates a drinking (potable) water supply to be protected from another water system

Minimum of one inch or twice the diameter of the incoming pipe whichever is greater

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O&M Review ►Types of backflow prevention devices: Air gap separation Double check valve Reduced-pressure principle (RPP) device Pressure vacuum breaker Atmospheric (non-pressure) vacuum breaker

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O&M Review Valves

► Gate Valve

Used for stopping or isolating ► Should be either all the way open or all the way

closed

► Butterfly Valve Used for non-critical throttling applications

► Check Valve Stops back-flow in the piping Operates automatically Should be located on the discharge side of a pump

Gate Valves

Butterfly Valves

Check Valves

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O&M Review Air Vacs & Drains

►Use a #14 mesh screen for air vents and air vacuum release valves #14 mesh = 14 squares/inch

►Use a #4 mesh screen for overflow and drain lines #4 mesh = 4 squares/inch

Remember: an air vac vent pipe needs to be above the flood line

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Chemical Feed Review

►Pathogens Disease causing organisms Types: Bacteria, Viruses, Protozoa

►Viruses and cysts are more resistant to disinfection than are most bacteria

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Chemical Feed Review

►Disinfection Killing pathogenic organisms

►Sterilization Killing all organisms

►Chlorine kills bacteria by: Penetrating the cell wall and attacking a critical

cell enzyme

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Chemical Feed Review

►Calcium hypochlorite or HTH White granular powder 65% available chlorine

►Sodium hypochlorite, NaOCl Clear yellowish liquid 5 to 15% available chlorine

►Chlorine Dosage Formula Cl Dose = Cl Demand + Cl Residual

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Chemical Feed Review

►Chlorine residual test results provide the following information: Whether a residual exists Type of residual Amount of residual

►DPD A method of measuring the chlorine residual in

water Turns water pink or red

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Chemical Feed Review

►Factors Affecting Chlorination Concentration Contact Time Temperature

►At lower temps bacterial kill tends to be slower

pH ►Addition of chlorine lowers pH

Substances in the water ►Masks or shields

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Chemical Feed Review

►Chlorine Maximum Withdrawal Rates Ton containers

►400 lbs/day

150 lb. cylinders ►40 lbs/day

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Chemical Feed Review

►Chlorine Container Fusible Plugs Melt at 157 to 165 degrees Fahrenheit 150 lb. Cylinders

►One mounted on valve

Ton containers ►Three on each end

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Chemical Feed Review Fluoridation

►The purpose is to maintain the optimal level of fluoride needed by children to develop resistance to tooth decay

►MCL = 4.0 mg/L ►The optimal concentration to achieve the

maximum benefits of fluoridation is 1.0 mg/L ► SPADNS is the field test used to check for daily

fluoride concentrations

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