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

What are Chloramines? Chemicals that are formed when chlorine and ammonia are combined in water. Monochloramine (NH 2 Cl) Dichloramine (NHCl 2 ) Trichloramine (NCl 3 )

Benefits of Chloramine (compared to chlorine) More Stable Less Reactive (reduced THM formation) Longer Lived Residuals Effective Secondary Disinfectant Minimizes Objectionable Taste and Odors

Monochloramine is the Desired Form of Chloramine Most Stable Least Reactive (Reduced THM Formation) Least Taste and Odor

Chloramination Breakpoint Curve

Optimal Chloramination Control Range

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

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

Breakpoint with Fixed Cl 2

Chloramination Control Strategies Ratiometric control Cl2 : NH3-N ratio between 3:1 and 5:1 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

ChemScan Chloramination Analyzer Advantages Multiple Parameter Analysis Multiple Sample Line Fast Analysis Time Benign Waste Stream Non-Clogging Sample System Auto 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 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 Summary

Chloramination Installations Toronto, OntarioAirport Road WTP La Mesa, CAAlvarado WTP Zefferhills, FLPasco County S.E. WTP Houston, TXBilma WTP Hayward, CASkywest Pump Station Blacksburg, VABlacksburg WTP Hillsborough, FLHillsborough WTP Oakland, CAEast Bay MUD Hudson, FLPasco County Autumn Oaks WTP LADWP, CAStone Canyon WTP Houston, TXHC Mud286 LADWP, CASanta Ynez WTP Blanton, FLPasco County Blanton WTP Houston, TXMalcomson Rd. WTP San Francisco, CAHecht-Hetchy Sunol WTP LADWP, CAGreen Verdego I WTP Washington, DCDale Carila WTP Houston, TXHeatherlock WTP Coalinga, CACoalinga WTP Hillsborough, FLWTP/Blend Stations Fremont, CAAlameda County Water Dist. Elsinore Valley, CAInland Valley Pump Station LADWP, CAStone Mountain Houston, TXHC Mud52 Holiday, FLPasco County S.W. WTP Colncord, CAContracosta WTP Ontario, CanadaUnion Water Treatment Plant Washington, DCTP WTP Pasco County, FLPasco County WTP Inglewood, CAInglewood WTP Lehigh Acres, FLLehigh Acres WTP Houston, TXKleinwood WTP Arcadia, FLArcadia WTP Miami, FLMiami Dade WTP Wausau, WIWater Works Houston, TXBridgestone WTP Charlotte Co. FLBurntstore WTP Pomona, CAWell 7 & 8 Palm Beach Co. FLPalm Beach WTP West Lake, CAWest Lake WTP Louisville, KYLouisville WTP Milwaukee, WIHoward Avenue WTP Newport Richey, FLPasco County Little Road WTP Signal Hill, CASignal Hill WTP St. Joe Beach, FLSt. Joe Beach WTP Oakland, CAEast Bay MUD Houston, TXHC Mud16 LADWP, CAGreen Verdego III WTP Houston, TXHC Mud191 Alameda County, CAPlant and Distribution Houston, TXHC Mud286 Charleston, SCHanahan WTP Dallas, TXHarpool WTP Manchester, IAManchester WTP Florida City, FLFKAA LADWP, CAGreen Verdego II WTP Hillsborough, FLFawn Ridge WTP Hayward Hesperian, CAHesperian Booster Pump Station WTP Hillsborough, FLLake Park WTP San Francisco, CAHecht-Hetchy Pulgas WTP Hillsborough, FLLithia WTP Houston, TXHC Mud200 Hillsborough, FLCentral WTP LADWP, CAEagle Rock WTP Dade City, FLPasco 1 LADWP, CASanta Ynez WTP Lehigh, FLLehigh WTP

ASA Analytics Chloramination Presentation