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What are Chloramines?Chemicals that are formed when chlorine and ammonia are combined
in water.Monochloramine (NH2Cl)
Dichloramine (NHCl2)
Trichloramine (NCl3)
Benefits of Chloramine (compared to chlorine)
More StableLess Reactive (reduced THM formation)Longer Lived ResidualsEffective Secondary DisinfectantMinimizes Objectionable Taste and Odors
Monochloramine is the Desired Form of Chloramine
Most StableLeast Reactive (Reduced THM Formation)Least Taste and Odor
Chloramination Control ChallengesMaintain Adequate Disinfectant Concentration to Ensure
Safe WaterFeed Enough Ammonia to Prevent Di and Trichloramine
Formation and Prevent Drop in Chlorine ResidualPrevent Over Feed of Ammonia to Minimize the Potential
of Nitrification in the Reservoirs and Distribution SystemOn-Line Analysis Provides the Information Required to
Control the Chloramination Process
Breakpoint as Measured by Free and Total Chlorine Analyzers
A Total Chlorine result has 3 possible locations on the breakpoint curve Free Chlorine reacts with Monochloramine giving a false reading until beyond the Breakpoint First Indication of Free Chlorine is AFTER Dichloramine Formation
Break-point Curve as Read on ChemScan On-Line Analyzer
At ratios below 5:1, Total Chlorine and Monochloramine values are equivalent
Between the ratios of 5:1 and 8:1, Total Chlorine is greater than Monochloramine as Dichloramine is formed
At ratio greater than 8:1, Free Chlorine is present
At ratios below 5:1, Total Ammonia remains constant as Free Ammonia decreases until reaching 5:1
At ratios greater than 5:1, Total Ammonia decreases and free ammonia is near zero
Fixed NH3-N 0.6 mg/l With Increasing Cl2
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
0 1.67 3.33 4.17 5 5.83 6.67 8.33 10
Actual Cl2:N Ratio
mg
/l
Mono + Free Cl2 Total Cl2 Free NH3Total NH3 Calc. Dichloramine
0
0.2
0.4
0.6
0.8
1
1.2
0
0.5
1
1.5
2
2.5
3
3.5
0 1.9 3.9 4.8 5.8 6.7 7.7 8.8
NH
3 m
g/l
Cl2
mg
/l
Actual Cl2:N Ratio
Fixed Cl2 3.0 mg/l Varying NH3
Mono Cl2 Total Cl2DI Cl2 Free NH3Total N
Breakpoint with Fixed Cl2
Chloramination Control StrategiesRatiometric control
Cl2 : NH3-N ratio between 3:1 and 5:1Measures total chlorine from all forms and total ammonia
from all forms (free and combined)Residual control
Maintain small free ammonia residualMaintain target monochloramine
ChemScan Chloramination Analyzer Advantages
Multiple Parameter AnalysisMultiple Sample LineFast Analysis Time Benign Waste StreamNon-Clogging Sample SystemAuto Zeroing and Clean
Benign Reagents
Sodium Hydroxide (NSF Std 60 Certified)
Sodium Hypochlorite (NSF Std 60 Certified)
Sulfuric Acid (NSF Std 60 Certified)
Potassium Iodide (NSF Approved)
Hydrochloric Acid (NSF Std 60 Certified)
Chloramines are Effective DisinfectantsMonochloramine has Least Odor and TasteChloramination can be Difficult to Control
Too little ammonia cause di and trichloramine formation and loss of chlorine residual
Too much ammonia can cause nitrification in reservoirs and distribution system
Effective On-Line Analysis Equipment will Aid in the Control of the Chloramination Process
Summary
Chloramination Installations Toronto, Ontario Airport Road WTP
La Mesa, CA Alvarado WTP Zefferhills, FL Pasco County S.E. WTPHouston, TX Bilma WTPHayward, CA Skywest Pump StationBlacksburg, VA Blacksburg WTPHillsborough, FL Hillsborough WTPOakland, CA East Bay MUDHudson, FL Pasco County Autumn Oaks WTPLADWP, CA Stone Canyon WTPHouston, TX HC Mud286LADWP, CA Santa Ynez WTPBlanton, FL Pasco County Blanton WTPHouston, TX Malcomson Rd. WTPSan Francisco, CA Hecht-Hetchy Sunol WTPLADWP, CA Green Verdego I WTPWashington, DC Dale Carila WTPHouston, TX Heatherlock WTPCoalinga, CA Coalinga WTPHillsborough, FL WTP/Blend StationsFremont, CA Alameda County Water Dist.Elsinore Valley, CA Inland Valley Pump StationLADWP, CA Stone MountainHouston, TX HC Mud52Holiday, FL Pasco County S.W. WTPColncord, CA Contracosta WTPOntario, Canada Union Water Treatment PlantWashington, DC TP WTPPasco County, FL Pasco County WTPInglewood, CA Inglewood WTPLehigh Acres, FL Lehigh Acres WTPHouston, TX Kleinwood WTPArcadia, FL Arcadia WTPMiami, FL Miami Dade WTPWausau, WI Water Works Houston, TX Bridgestone WTPCharlotte Co. FL Burntstore WTPPomona, CA Well 7 & 8Palm Beach Co. FL Palm Beach WTPWest Lake, CA West Lake WTPLouisville, KY Louisville WTPMilwaukee, WI Howard Avenue WTPNewport Richey, FL Pasco County Little Road WTPSignal Hill, CA Signal Hill WTPSt. Joe Beach, FL St. Joe Beach WTPOakland, CA East Bay MUDHouston, TX HC Mud16LADWP, CA Green Verdego III WTPHouston, TX HC Mud191Alameda County, CA Plant and DistributionHouston, TX HC Mud286Charleston, SC Hanahan WTPDallas, TX Harpool WTPManchester, IA Manchester WTPFlorida City, FL FKAALADWP, CA Green Verdego II WTPHillsborough, FL Fawn Ridge WTPHayward Hesperian, CA Hesperian Booster Pump Station WTPHillsborough, FL Lake Park WTPSan Francisco, CA Hecht-Hetchy Pulgas WTPHillsborough, FL Lithia WTPHouston, TX HC Mud200Hillsborough, FL Central WTPLADWP, CA Eagle Rock WTP Dade City, FL Pasco 1LADWP, CA Santa Ynez WTPLehigh, FL Lehigh WTP
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