Chloramination

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Chloramination

• On-Line Chloramination Monitoring and Control
• Scott Kahle, ASA/ChemScan

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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)

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Benefits of Chloramine (compared to chlorine)

• More Stable
• Less Reactive (reduced THM formation)
• Longer Lived Residuals
• Effective Secondary Disinfectant
• Minimizes Objectionable Taste and Odors

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Monochloramine is the Desired Form of Chloramine

• Most Stable
• Least Reactive (Reduced THM Formation)
• Least Taste and Odor

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Chloramination Breakpoint Curve
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Optimal Chloramination Control Range
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Chloramination Control Challenges

• Maintain Adequate Disinfectant Concentration to
  Ensure Safe Water
• Feed Enough Ammonia to Prevent Di and
  Trichloramine Formation and Prevent Drop in
  Chlorine Residual
• Prevent Over Feed of Ammonia to Minimize the
  Potential of Nitrification in the Reservoirs and
  Distribution System
• On-Line Analysis Provides the Information
  Required to Control the Chloramination Process

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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

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Break-point Curve as Read on ChemScan On-Line
Analyzer
At ratios below 51, Total Chlorine and
Monochloramine values are equivalent Between the
ratios of 51 and 81, Total Chlorine is greater
than Monochloramine as Dichloramine is formed At
ratio greater than 81, Free Chlorine is
present
At ratios below 51, Total Ammonia remains
constant as Free Ammonia decreases until reaching
51 At ratios greater than 51, Total Ammonia
decreases and free ammonia is near zero
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Breakpoint with Fixed Cl2
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Chloramination Control Strategies

• Ratiometric control
• Cl2 NH3-N ratio between 31 and 51
• Measures total chlorine from all forms and total
  ammonia from all forms (free and combined)
• Residual control
• Maintain small free ammonia residual
• Maintain target monochloramine

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ChemScan Chloramination Analyzer Advantages

• Multiple Parameter Analysis
• Multiple Sample Line
• Fast Analysis Time
• Benign Waste Stream
• Non-Clogging Sample System
• Auto Zeroing and Clean

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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)

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Summary

• Chloramines are Effective Disinfectants
• Monochloramine has Least Odor and Taste
• Chloramination 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

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Chloramination Installations
Toronto, Ontario Airport Road WTP
La Mesa, CA Alvarado WTP
Zefferhills, FL Pasco County S.E. WTP
Houston, TX Bilma WTP
Hayward, CA Skywest Pump Station
Blacksburg, VA Blacksburg WTP
Hillsborough, FL Hillsborough WTP
Oakland, CA East Bay MUD
Hudson, FL Pasco County Autumn Oaks WTP
LADWP, CA Stone Canyon WTP
Houston, TX HC Mud286
LADWP, CA Santa Ynez WTP
Blanton, FL Pasco County Blanton WTP
Houston, TX Malcomson Rd. WTP
San Francisco, CA Hecht-Hetchy Sunol WTP
LADWP, CA Green Verdego I WTP
Washington, DC Dale Carila WTP
Houston, TX Heatherlock WTP
Coalinga, CA Coalinga WTP
Hillsborough, FL WTP/Blend Stations
Fremont, CA Alameda County Water Dist.
Elsinore Valley, CA Inland Valley Pump Station
LADWP, CA Stone Mountain
Houston, TX HC Mud52
Holiday, FL Pasco County S.W. WTP
Colncord, CA Contracosta WTP
Ontario, Canada Union Water Treatment Plant
Washington, DC TP WTP
Pasco County, FL Pasco County WTP
Inglewood, CA Inglewood WTP
Lehigh Acres, FL Lehigh Acres WTP
Houston, TX Kleinwood WTP
Arcadia, FL Arcadia WTP
Miami, FL Miami Dade WTP
Wausau, WI Water Works
Houston, TX Bridgestone WTP
Charlotte Co. FL Burntstore WTP
Pomona, CA Well 7 8
Palm Beach Co. FL Palm Beach WTP
West Lake, CA West Lake WTP
Louisville, KY Louisville WTP
Milwaukee, WI Howard Avenue WTP
Newport Richey, FL Pasco County Little Road WTP
Signal Hill, CA Signal Hill WTP
St. Joe Beach, FL St. Joe Beach WTP
Oakland, CA East Bay MUD
Houston, TX HC Mud16
LADWP, CA Green Verdego III WTP
Houston, TX HC Mud191
Alameda County, CA Plant and Distribution
Houston, TX HC Mud286
Charleston, SC Hanahan WTP
Dallas, TX Harpool WTP
Manchester, IA Manchester WTP
Florida City, FL FKAA
LADWP, CA Green Verdego II WTP
Hillsborough, FL Fawn Ridge WTP
Hayward Hesperian, CA Hesperian Booster Pump Station WTP
Hillsborough, FL Lake Park WTP
San Francisco, CA Hecht-Hetchy Pulgas WTP
Hillsborough, FL Lithia WTP
Houston, TX HC Mud200
Hillsborough, FL Central WTP
LADWP, CA Eagle Rock WTP
Dade City, FL Pasco 1
LADWP, CA Santa Ynez WTP
Lehigh, FL Lehigh WTP
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ASA Analytics ChloraminationPresentation