Water Treatment Terminology Operation & Maintenance GPM= gallons per minute MGD= million gallons per day TTHM= total trihalomethane Exam Review PSI= pounds per square inch NTU= Nephelometric Turbidity Unit mg/L= milligrams per litre or ppm= parts per million Feet of Head
Purpose of Treatment Process Pathogenic Screens Remove debris Disease causing organisms Pre-chlorination Kills pathogens, controls Includes Viruses, Protozoa, or taste and odors. Possible Bacteria problems with DBP’s Causes diseases such as Use UV or Ozone instead typhoid, cholera and dysentery Chemicals Organisms that don’t cause Assist with the process disease are non-pathogenic Flash mixer Mixes chemicals with water Coagulation/flocculation Slowly mixes the chemical and particles together.
Intakes & Screens Thermocline Multiple inlet intake structures allows operators to pull from Epilimnion- upper layer that depth of better quality circulates warm water where dissolved oxygen Should prevent large debris & fish from entering treatment plant concentrations are moderate to high Should be designed to handle Thermocline - separates flows upper an lower layers Manually cleaning screens for Hypolimnion , a cold, deep- small amounts of debris water, non-circulating layer Turnover cause mainly by change in which oxygen is low or in water temperature & density absent
1 Pre-sedimentation Aeration
Removal of debris Removes dissolved Helps control impact of changing raw water gases Removes dissolved Impoundments are types of pre-sedimentation metals such as iron systems Releases volatile chemicals
Coagulation/Flocculation Primary Coagulants Zeta Potential The repelling force that keeps particles separated Aluminum sulfate Coagulation Ferrous sulfate Is the adding & rapid mixing of chemical coagulants in water to reduce turbidity prior to filtration Ferric sulfate Is a chemical reaction between coagulant, turbidity, & alkalinity. Cationic polymer Neutralizes negative (-) charges Calcium hydroxide Flocculation is a process that form floc to settle out impurities in the water & reduce turbidity prior to filtration Calcium oxide Floc grows with the collision of the particles Sodium aluminates Troubleshooting Paddle speed- slow speed floc will settle prematurely Velocity through basin Short circuiting
Coagulant Aids Sedimentation Allows solids to settle out before filtration Sedimentation - With Settling Tubes Calcium hydroxide As required by drinking water rules Calcium oxide Sedimentation - Without Settling Tubes 2 hours detention time Sodium aluminates WLR (weir loading rate) <20,000 g/d/ft Bentonite weir length Head on rectangular weir is measured Calcium carbonate from crest to top of water on weir plate Sodium silicate 0.5 fpm velocity 8 to 12 ft depth Anionic polymer Nonionic polymer
2 Sedimentation Tube Settler Sedimentation Troubleshooting Short circuiting Temperature Working properly determined by the measurement of turbidity in compared to turbidity out. Wind currents Velocity Increase in flow Floating materials Sludge removal Sludge accumulation Noisy drive chain
Filtration Systems Filtration Systems
Conventional – Pressure Filters Conventional Treatment Non-conventional Screens Screens Direct filtration Pre-chlorination Pre-chlorination *No sedimentation Chemicals Chemicals Flash mixer Flash mixer Slow sand filter Coagulation/ *Coagulation, Flocculation, *No: Chemicals flocculation Sedimentation, & Filtration Flash mixing Sedimentation Post chlorination Coagulation Filtration Flocculation Chemicals Post chlorination Sedimentation Clear well Chemicals Clear well
Filtration Filtration Rates
Removes small contaminants Terminal Head Loss water can no longer be
Bacteria- Salmonella, E. Coli filtered Protozoan- Giardia, Cryptosporidium Recommended flow rates are 15 to 20 GPM per Virus- Hepatitus A, Rotavirus square foot Types Closing inlet valve & measure drop in the water Mechanical filter level over time you can determine flow thru filter Absorption filter Too large of floc can cause the filter to clog at a Slow sand rapid rate Rapid sand Mixed media Filter Loading rates are defined as gallons of Highest rate of flow water applied to each square foot of filter surface Water flows through the filter by percolation area Head loss gauge measures pressure drop as water passes thru the filter
3 Multimedia Filter - Sand Filter Media Types - Garnet - Coal Sand Anthracite Garnet Granular Activated Carbon Green Sand Measured by sieve analysis to determine size
Filtration FILTRATION
Removes small contaminants Trouble shooting Bacteria Method of determining flow through a filter Protozoan without a meter. Virus Measure the rise or fall of the water in the filter Types over time Mechanical filter Used for removal of Giardia & Cryptosporidium Absorption filter Aeration Slow sand Dissolves gases Rapid sand Dissolves metals Mixed media Removes volatile chemicals Highest rate of flow Water flows through the filter by percolation
FILTRATION Disinfection
Process to kill or inactivate most pathogens in water. Trouble shooting There are several ways to Mud balls disinfect Improper surface washing or backwashing Chlorine is most popular Air binding method because of cost and it leaves a residual throughout Cold water the system Negative pressure head in lower filter UV Cracking Ozone- doesn’t leave a Septic smell measurable residual in system
4 Breakpoint Chlorination Graph Disinfection By-products
Chlorine smell would indicate you need to add more TTHM- Total Trihalomethanes to reach breakpoint Adsorption where molecules collect & adhere to a surface of an adsorbent solid (GAC) would help reduce TTHM’s Combination of chlorine and organics Warmer temperatures and pH form THM’s faster THM precursors would indicate THM forming throughout the system Aeration & Clarification can remove THM precursors
Organic Matter Under Drains TTHM Total trihalomethanes Used for backwashing MCL = 80 ppb (0.080 mg/l) Collects the filtered HAA5 water Haloacetic acids Keeps the media bed in MCL = 60 ppb (0.060 mg/l) the filter. Reduction and removal through: Absorption Aeration Oxidation Clarification
Backwash Filter Head Loss Gauge
Open backwash valve slowly Used to measure drop Backwash is based on: in pressure thru filter Increase in Effluent Turbidity Terminal head loss = Head Loss No water flowing Filter Run Times determined by plant (many use 36 hrs) Backwash duration depends on amounts of sludge & debris in filter Typical Backwash Rate: 15 to 20 gpm/sq.ft .
5 Surface Washer Sludge Collectors
Mudballs and surface mats are reduced Fix noisy drive chains by tightening and aligning the chain & casing
3 Most Important Monitoring Parameters For Safe Drinking Water Jar Testing
Bacteria Duplicates the treatment plant Turbidity- operator has processes such as detention most control over time, mixing conditions & settling conditions Chlorine residual Helps provide optimal dosages Helps optimize coagulation process Floc remaining longer than 15 to 20 minutes probably won’t settle out
Water Hardness Water Hardness & Corrosion Caused by salts of calcium & magnesium (bicarbonate, Objectionable tastes carbonate, sulfate, chloride & Magnesium leaves black stains nitrate) Galvanic Corrosion cause by Causes formation of soap dissimilar metals in a drinking water curds system Increased use of soap Hardness test uses EDTA titrant Deposits in boilers & fixtures Expressed as mg/L CaCO3 Soft water considered as 0 to 50 Damages industrial processes mg/L of CaCO3 High dissolved CO2 would increase corrosion
6 Corrosion C-Factor
Electrochemical phenomenon observed as red water Indicates the smoothness pipe Calcium carbonate saturation used for corrosion control material Measurements: The higher the C value, the Langelier index smoother the pipe. Positive number: Deposit To calculate measure flow, pipe Negative number: Corrosive diameter, distance between two Metal coupons used to measure corrosiveness of pressure gauges, and the water – determined by weight loss of coupon friction losses between the gauges. Adjustments can be accomplished by: Chemicals which increase or decrease the depositing, Tuberculation reduces C value or Sequester the problem with the use of polyphosphates PVC has higher C- factor than concrete
Head Loss FRICTIONAL HEADLOSS
Friction head loss: caused by valves, bends, pipe Energy used up by water movement roughness, etc. Two Conditions that affect head loss: Water hardness caused by calcium & magnesium 1. Roughness Coefficient tests can indicate 2. Velocity whether or not friction losses are increasing . Two Conditions that affect Roughness: Galvanic corrosion can 1. Age – Condition happen when connecting brass to steel 2. Type of pipe Materials
Iron Consumer complaints Turbidity- NTU’s Can cause stains on laundry & fixtures The following is the most Formation of iron bacteria that form slick frequent method used to slimes on pipe walls water quality & the Taste and odor problems cloudiness of the water Reacts with chlorine increasing use Uses light to measure Removed thru aeration and filtration The higher the NTU, the Iron & manganese react with dissolved dirtier the water, the more oxygen forming insoluble compounds possibility of micro- biological contamination Polyphosphates & flushing reduce iron deposits NTU= Nephelometric Turbidity Unit
7 Turbidity Particle Counter
Physical characteristic of water making it appear cloudy. The method used to Caused by suspended matter. measure the cloudiness of the water – the amount of The most monitored treatment of water for quality. particles and the size of particles. The greatest control factor in treatment of water. The dirtier the water, the Increased influent turbidity means an increase greater the possibility of in chemicals microbiological Masks pathogens from disinfections . contamination.
pH Alkalinity pH: expression that refers to the basic or acidic conditions of the water A measurement of the water’s capacity to pH is measured on a scale from 0 to 14. neutralize an acid Less than 7 is more acidic, greater than 7 is more basic or higher alkalinity. 7 is Alkalinity is determined by titrating to an end neutral. point with a pH meter or the use of the methyl PVC pipe is least affected by acidic water Reinforced concrete pipe would most likely orange test corrode in acidic water Corrosiveness on pipes can be detected by Use sulfuric acid to perform test plotting Baylis Curve or Langlier Index Affects the coagulation process Weight of metal coupons used to determine corrosiveness The higher the alkalinity, the better the floc A negative number on Langlier Index would formation be corrosive
pH Temperature Characteristics of Temperature The colder the water, the more dense. Any substance that releases HYDROGEN IONS (H+) when The colder the water, the less activity. mixed with water is acidic (0-6) Higher disinfection concentration is required Any substance that releases HYDROXYL IONS (OH-) is a base (8-14) in cold water. Low temps decrease the rate of floc settling Alkalinity changes will affect the coagulation process F (Fahrenheit) C (Celsius) pH is measured by use of a PROBE OR A COLORIMETRIC METHOD. SIGNIFICANCE: Main impacts Affects chlorination, coagulation, softening, and Affect to speed of biological and chemical corrosion reactions Affect to rate of biological decomposition CO 2 – Carbon dioxide reduces the pH Changes to chlorine demand
8 Chemicals Temperature
Low temperatures the bacteria kill rate is lower Chemical Storage Chlorine residual will remain Cool, dry place longer in cold water Away from general traffic Warm water will cause bacteria Non-treatment chemicals to bloom Spillage control – clean plan Calcium Carbonate will form more rapidly in hot water Empty drum disposal Temperature drops would According to manufacturer’s recommendation cause carryover in sed. basins
Aluminum Sulfate (Alum) Chemical Compounds Part of coagulation/flocculation process & creates the floc Aluminum sulfate An anhydrous acid Ferrous sulfate Affects skin and mucous tissues Need goggles, face shields, dust mask, gloves, Ferric sulfate boots, rubber apron, clothing to protect skin & proper ventilation Cationic polymer MCL for atmosphere Calcium hydroxide 15 mg/cm for 8 hours When added to water: Calcium oxide Dissolved Sulfate increases Sodium aluminates Alkalinity decreases Calcium Carbonate pH decreases MCL in finished water is 450 mg/l
Alum Ferric Chloride
Alum is a mild Is a very corrosive material corrosive Should prevent splashing Never use the same conveyor system for Use eye protection, rubber alum and quicklime gloves, and protective clothing Potential for explosion When spilled on skin, flush pH below 5 floc won’t with large amounts of water form properly
9 Chemicals Chlorine Corrosion Control Fluoridation Gas is heavier than air Calcium hydroxide Sodium fluorosilicate Have eyewash/shower available Most leaks occur around control valve Hydrated lime- Sodium fluoride increases pH Cylinder liquid form expands 460 times Fluorosilicic acid Sodium hydroxide When changing cylinders, shut gas off at Hydrofluoric acid Caustic soda cylinder first, evacuate lines SPADNS test for fluoride Softening Produces hydrochloric acid mixed with moisture Calcium oxide Use rubber gloves & ventilate Quicklime Should practice response once per year Sodium carbonate Inspect daily for leaks in system Soda ash Higher alkaline = more chlorine
Chlorine Leaks Three Forms of Chlorine
POWDER 65%- HTH (High Test Put on SCBA Hypochlorite) Calcium Hypochlorite Turn on ventilation fan LIQUID-Sodium Hypochlorite Have help standing by *Bleach 5% *T-Chlor 15% GAS 99.9% *extremely corrosive with water/humidity *compressible *changes to liquid at 82 psi *68 deg. F *2.5 times heavier than air *greenish-yellow color * Must meet NSF approval
Calcium Hypochlorite & Quicklime Chloramines
Calcium Hypochlorite Quicklime Can create heat & oxygen Extremely caustic material Formation of chloramines is a chemical to start a fire Reacts violently with water reaction HTH- High Test Reaction can cause fire or Hypochlorite explosion The reaction is between hypochlorous Store totally dry area acid (or aqueous chlorine) with Do not allow to mix with ammonia . alum Formation of chloramines weakens the disinfecting strength of chlorine
10 Chloramination DPD
Method of measuring chlorine residual in Cloramines are a reaction the water between applied chlorine Testing agent turns and ammonia chlorinated water a When done intentionally it pink color. More can reduce tastes and intense color, higher odors residual. Chloramines are a weaker DPD= N,N-diethyl-p- disinfection than chlorine phenylene-diamine
Fluoride Over Feeding Fluoride
Victims exposed to large Can Mottle Teeth amounts should me removed from area Operators should know the hazards contained in MSDS Can cause dental stains & mottling of teeth SPADNS test to analyze fluoride levels
Caustic Soda Safety Chemical Safety for Acids
Chemicals cause visible Strong caustic alkali and very hazardous destruction or irreversible damage to skin tissue at the Very reactive point of contact Dissolves human skin Swallowing can damage Generates heat with when esophagus & stomach . mixed with water Wear personal protective Reacts with amphoteric equipment metals generating Flush affected area with clean hydrogen gas which is water flammable or explosive Use sodium bicarbonate to Use special precautions neutralize acids when handling Add acid to the water
11 Polymers Polymers
Used as coagulant and Filtration aid filter aids Not enough: Keep polymer dust off Rapid turbidity break through floors Too much: Will create very slippery Rapid increase in head loss surfaces when on floors Use inert, absorbent material such as sand to clean up spills
Potassium Permanganate Explosions Strong oxidizing agent , use caution Turns water pink Will react easily with organic Don’t use sawdust to materials absorb liquids Will ignite when in contact with antifreeze, sawdust compounds and Powder activated many other materials carbon is the most All lubricants & fuels are potential fire hazards volatile powder Store separately from other Methane is the most chemicals in a cool dry location common combustible Use dust masks and rubber gloves when handling & for cleaning up gas Used for taste & odor, TTHM control, reduces Iron, Hydrogen Sulfide (rotten egg smell) & Manganese
Activated Carbon Taste & Odor Used for taste & odor problems Is considered the most volatile powder Activated Carbon & KMNO4 are chemicals Keep away from Cl2 compounds and KMnO4, possible spontaneous combustions used The main problems are dust and fire control Will burn with intense heat , and without Threshold Odor Number (TON) is a unit of smoke or visible flame measure for odors in water & should be Keep electrical equipment clean Carbon dust can cause short-circuit fires conducted at 60 deg. Celsius Use explosion-proof electrical equipment Water devoid of oxygen produces odor and Used prior to chlorination because they react with each other anaerobic bacteria growth Sludge accumulations could cause problems
12 Algae Control Chemical Nitrite – Cause & Effect
Cause Large concentration of fertilizers. Copper Sulfate Effect Indicators that affect Blue-baby syndrome copper sulfate: High Nitrate Levels Alkalinity MCL 10 mg/1 Type of algae Temperature 5 mg/1 – quarterly monitoring Nitrate turns in nitrite and replaces oxygen in blood. Thus babies and immuno-deficient individuals are affected.
Sampling Fusible Plug
Grab samples taken in 150 lb. Cylinder Valve Composite Sample Safety Device instantaneous Made out of lead conditions at certain Melts between 160 to times & locations 165 degrees
Bacteriological Sampling Bacteriological Sampling Procedures Procedures
If sample is OK, this only Should allow sample tap water to run several minutes or as long as necessary indicates that water was safe at Not smooth nosed point of sample to clear service line Coliform is an indicator of Sampling bottle/bag should be filled to bacteria presence just above fill line or 1 inch from top Sample should be transported Results are meaningless if sample is as soon as possible in a cool contaminated container with ice pack Sample identification cards need to filled Routine bacti’s should be taken out completely at the customers tap at various Should be sterilized by lab points that represent the entire Sodium Thiosulfate system Dechlorination agent in bacteriological sample container
13 Coliform GWR
Coliform= a group of bacteria December 1, 2009 found in the intestines of warm blooded animals & also plants, TC+ bacterial Samples soil, air and water Requires Triggered Source Water sample (TSW) Total Coliform = a measurement Of all sources that were in operation at time of that shows if coliform bacteria is present in a water system & are +TC sample an indicator organism Email on sources not sampled – not running Fecal Coliform = a specific class Test for fecal coliform of bacteria coming from animal intestines. If sample is coliform positive, a fecal coliform test is performed.
Sanitary Surveys Performed GWR continued By
Executive Secretary shall ensure a sanitary 5 addition samples if first TSW is Fecal+ survey is conducted at least every 3 years 2 or more sources requires you to submit Division of Drinking Water new sample site plan DEQ District Engineers Correct significant deficiencies within 120 Local Health Departments days Forest Service Engineers Utah Rural Water Association staff Consulting Engineers Others authorized by Executive Secretary
Aesthetics Electrical Motor
Clean dust from a motor with compressed air. Means attractive or appealing. Measure speed with With respect to water it means tachometer taste, odor, or coloration of the Auxiliary motors can be water. used in emergencies Things that affect this are extreme Brake HP is amount of hardness or high total dissolved HP supplied by the solids motor to the pump Effects range from bad smell and poor taste to causing stains on laundry and/or fixtures
14 Circuit Breaker Electric Motors Opens or closes the electrical circuit to motors
Function as overload device Upon start up an electric motor will develop a load to turn the Opens automatically when an overload occurs to pump shaft and impeller protect circuit Torque causes motor to draw a high amperage To change rotation on 3 phase, switch any 2 leads Voltage imbalances cause 3 phase motors to overheat & burn out the insulation Tachometer used to determine speed of motor/pump
Volt – Ohm Meter Transformer
Volts Measure of the force of electrons The purpose of the Set the volt meter at a transformer is to higher setting than the voltage being measured. increase (step up) or decrease (step Ohms down) voltage. Measurement of resistance Amps Measurement of the flow of electrons
Confined Spaces Security
Carbon dioxide will Deter settle near floor Detect Blowers are the most effective means to Delay reduce atmospheric Respond hazards Ventilate until proper oxygen levels are reached (minimum19.5%)
15 Safety Security Distribution Systems
Looped systems have continuous Reservoir sites flow & less water quality problems Water quality problems could indicate a closed valve or partially Sources open Main Offices Leak surveys done at night Water mains 10 Feet horizontal distance from Vehicles sewer main Water main and sewer mains must Vaults cross at least 18” of separation Water line is on top Water & sewer not installed in the same trench. Leaks will get worse not better
Maintenance Records Ground Water - Wells
Water bearing Why keep maintenance records? formation called an Develop preventative maintenance program aquifer Prolong life of equipment Maps Maintain backup equipment Reduce liabilities Improve customer service
New & Repaired Water Mains Water Distribution Systems
Operation and Maintenance Pressure test Water main design Disinfected in accordance with Distribution system pressures AWWA standard C651 20 psi at all times Must be disinfected with some Peak instantaneous flows type of chlorine Minimum Water main size Tablet or a solution are typically 8 inch with fire hydrants used Unless you have an engineer signature to buy off on Chlorine must be flushed with it potable water 4 inch without fire hydrants Take chlorine residuals Must take bacteria samples
16 New Minimum PSI Standards Thrust Blocking
Thrust Block - a concrete mass cast in place between a fitting and Maintain minimum of 20 psi at all times the undisturbed soil at the side or For Construction after 3/1/06 bottom of the pipe trench. Purpose is to keep fittings from *20 psi during fire flow moving & either coming loose or apart from the force of the water *30 psi during peak instantaneous demand pressure in the pipe. *40 psi during peak day demand Needs to be centered on the thrust force
Water Storage Reservoir Storage Reservoirs
Provides a volume of water to the water system during 2 categories of paint- long life and short life average and peak demands Frequent pumping & changing depth can Provides adequate pressures reduce freezing throughout the water systems Sandblasting is recommended to prepare Covered to prevent bacti & inside for painting, inspect every 3 to 5 years algae growth Stagnant water causes quality problems Reserve storage Fire protection They’re most susceptible to water quality degradation from external sources
Parts of a Well Parts of a Well
Pumps from a geologic formation called an aquifer Well Screen – unrestricted water flow and When water passes through porous layers of soil it’s small enough to stop sand from entering called percolation Gravel pack – aids screen in filtering sand. 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)
17 Wire to Water Efficiency Cavitation
Energy required to overcome pump inefficiencies Main cause of losing pump suction Sounds like pumping rocks or pinging The combined efficiency of the pump and Vibration & popping noises caused by low the motor together. Also called the over all pressure in volute efficiency. Generally caused by vapor bubbles Water HP HPx100 = % Wire to Water Efficiency Vapor bubbles implode causing damage to pump Motor HP Volute case needs to be full of water (Flow, gpm) (Total Dynamic Head, ft) (0.746 kw/hp) (100) = % WWE Prevented by having adequate suction (3,960) (Electrical Demand, kilowatts) pressure and proper bowl depths
Cross Connections Air Gap- Safest Method Cross connection: a connection between a potable & an unapproved source. A physical break between the Caused most disease outbreaks end of a pipe and an open Two Types of Backflow vessel flood rim *Backsiphonage : backflow caused by a negative or • Minimum of 1” or two times the below atmospheric pressure in a water system where diameter of the pipe. a vacuum exists such as draining as system (fire Backflow protection fighting can cause) • Backsiphonage *Backpressure : when users pressure is higher than Hazard the system pressure • High degree or health risk Approved assemblies are used to keep contaminants Required on all sewer, out the drinking water system wastewater or sludge Protection established by degree of hazard connections
Meter Sizing Considerations AWWA C651 – Water Mains
Pressure at the service connection Methods Highest fixture in the building being served Any back flow prevention device Tablet or granular – 25 mg/l – 24 hours A 5/8 inch meter should be tested every 5 to 10 Continuous Feed – 10 mg/l after 24 hours years. Fill main with water Meter should not have more than 20 psi of head Flush out debris loss. Fill with chlorinated water In absence of a flow meter on a filter you can close the inlet valve and measure the drop over time.
18 AWWA C651 Water Mains AWWA C651-05 Continued
Final flushing Slug method Clearing main of heavily chlorinated water 3 hour exposure of not less than 50 mg/l Disposing chlorinated water Start with 100 mg/L and test at intervals on pipe Discharge can cause damage to the environment If residual drops below 100 mg/L move equipment Neutralizing agents Sulfur dioxide, sodium biosulfates, sodium sulfide, sodium thiosulfates, ascobic acid Flushing at 2.5 fps Scour the insides of the pipe.
Procedure existing water mains Bacteriological Testing
Positive pressure during repairs Standard Conditions Swabbing AWWA C651-05 2 samples - 24 hours apart Flushing One set collected every 1200 feet Slug chlorination Plus one set from ends of main 300 mg/l – 15 minutes At least one on each branch Sampling – to prove procedure effectiveness
Bacteriological Testing Pressure Testing New Water Main
Special Conditions Pipe should sit idle for at least 24 hours Trench water entered Should be done at 150 psi Excessive quantities of dirt Water stand for 16 hours before 1 st test Or 1.5 times the normal pressures Sampling procedures Duration 4 Hours No hose No fire hydrant What does your ordinance say about testing Orem’s Ordinance
19 Valves Gate Valves - Isolation
Gate Valve: Isolation, should be either all the way open or all the way closed (least amount of head loss) Air and vacuum relief: allows air in and air to escape. Altitude valve: opens when system psi drops below a certain pressure and closes when the reservoir reaches a predetermined level. Glove valves used for flow & pressure regulating
Altitude Valve – good for regulating tanks Pump Control Valves
Minimizes water hammer Starts & stops on a closed valve
Valves Butterfly Valves -
Pressure Sustaining/Reducing: Higher resistance to maintain either upstream flow or downstream Operates easily & pressures depending on quickly the position of the pilot screw. They cost less than gate valves Need periodic service & maintenance Used for flow control
20 Ball & Plug Valves Sluice Gate & Sleeve Valves
Check Valves Water Hammer
Occurs when a valve is closed quickly or Permit flow in one pump shuts down and causes the water direction pressures to rise and fall rapidly. Swing Checks Sounds like some hammering on pipe. Spring loaded silent checks Can damage pipes, causing them burst.
Meter Sizing Considerations Meter Accuracy
Worn meters under register & Pressure at the service connection give the customer free water Highest fixture in the building being served Over time a worn meter will Any back flow prevention device cost the water system revenue. A 5/8 inch meter should be tested every 5 to 10 Formula: Meter Accuracy= years. (Meter,GPM)(100%)/Volume,GPM Meters should not have more than 20 psi of head Compound meters are used loss. for low to intermediate flows Meters one inch and smaller shouldn’t have more & occasionally for high flows than 15 psi of head loss Venturi meter is not a prime mover
21 Positive Displacement Meter Piston Meter
Nutating disk : nutating means nodding. When the water flows the disk rotates. Displacement type Water flows into a chamber and displaces piston Oscillating circular motion moves meter Higher head loss than nutating disk
Air Release Valves Velocity Meter (Air Vac) – air in & out
Should be placed at high points in the water system.
Propeller, Venturi, insertion Outlet should be screened about 12” min. above type, and most electronic ground types Rotors or propellers are turned be velocity of meter
Air Vacuum Air Release Combination
HYDROPNEUMATIC TANKS Line Collapse
Frequent on/off cycling indicates water logged tank Caused by not opening a downstream valve Operate by applying air pressure to tank before they began Tank levels controlled by pressure switches to pumps sucking water from the Air leaks can cause pumps to run continuously other end 1/3 to 2/3 air to water ratio limiting storage capacity A vacuum developed
before they realized PUMP CONTROL
what happened and the AIR RELIEF pipe pancaked PSI AIR BLADDER OR The pipe is the main DIAPHRAGM
transmission line to COMPRESSOR OPERATING LEVEL
supply water for the City PUMP PSI WATER LEVEL WATER AT MINIMUM of Folsom OPERATING PSI
22 Acronyms Acronyms
Forms of expressing a flow of water over a PSI = pounds per square inch period of time: The pounds of force on a given area. The area is expressed in a square inch. GPM 1 inch Gallons per minute MGD Million gallons per day 60 pounds 1 inch CFS Cubic feet per second 60 pounds per square inch, or 60 PSI
Acronyms Acronyms
Methods for measuring chemicals or other PVC, PE, ABS- refer to chemical composition of pipe constituents in drinking water Methods for measuring chemicals or other constituents in drinking water ppb ppm Parts per billion The measure of 1 gallon or lb. of a chemical in 1 billion gallons or Parts per million lbs. of water Refers to 1 gallon or lb. of a chemical in 1 million ug/l gallons or lbs. of water Microgram per liter The same measurement as ppb expressed in metric mg/l measurements Milligrams per liter 1000 ppb or ug/l = 1 ppm or mg/l Example: 80 ppb is the same as 0.080 mg/l The same measurement as ppm expressed in metric measurements
Definitions Fire Hydrants Toxic A substance that is poisonous to a living organism.
Potable Dry barrel hydrant used in areas Water that does not contain objectionable pollution, susceptible to freezing. contamination, minerals, or infective agents and is satisfactory to Drain hole allows water to drain from barrel drink. so water won’t freeze and crack the Culinary hydrant. Fit for human consumption. Hydrant bury is the distance below the Action Level : ground to the main connection. Required actions if lead and copper standards are exceeded: Because of increased population growth MCL and scaling of pipes, hydrant flow tests Lead – 15 ppb, or 0.015 ppm should be performed periodically. Copper – 1300 ppb, or 1.3 ppm
23 If the cut stake for a fire hydrant is marked AC- 4.25 @ and the hydrant is 7 ft. 6 in. tall, how high Thrust Blocking will the top be above the finished grade? Thrust Block - a concrete mass between a elbows, crosses & tees in undisturbed soil at the side or bottom of the pipe trench . Keeps fittings from moving & either coming loose or apart 7’ 6” convert to decimal from the force of the water C - 4.25 pressure in the pipe. 7.5 – 4.25 = 3.25 Thrust anchors – used when ? ft. 3.25 is the answer thrust blocks cannot be used Restrained fitting – use of clamps or anchor screws on fittings 7’6” Tie rods – used on mechanical 4.25’ joint fittings that a located close together Should be calculated & designed properly
Thrust Blocks 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%
Lightning Arrestor Screen Sizes
Becomes a low resistance #14 mesh for air vents conductor to ground when and air vacuum release the line voltage exceeds a valve #14 predetermined amount Air vac vent pipe above the flood line Used to protect equipment #4 mesh for overflow and from lightning strikes. drain lines No device made to protect #14 mesh = 14 squares against a direct hit. per inch #4 #4 mesh = 4 squares per inch
24 Electrolysis Tanks – Cathodic Protection
Decomposition of material by an outside electric current Electric current caused by movement of water in the line Cathodic protection installed to prevent
25