Treatment & Distribution Chloramine Optimization
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Treatment & Distribution Chloramine Optimization The York Water Company, Douglas Crawshaw Kershner Environmental Technologies, LLC, Christopher A. Evans, P.E.
Transcript of Treatment & Distribution Chloramine Optimization
Treatment & Distribution Chloramine OptimizationThe York Water Company, Douglas Crawshaw
Kershner Environmental Technologies, LLC, Christopher A. Evans, P.E.
Treatment & Distribution Chloramine Optimization
What Are Chloramines?
Chloramine Optimization Technology
The York Water Company
Project Goals
Upgrade Case History
o Water Treatment Plant Optimization
o Distribution System Optimization
What are Chloramines?
Chemicals that are formed when chlorine and
ammonia are combined in water.
o Monochloramine (NH2Cl)
o Dichloramine (NHCl2)
o Trichloramine (NCl3)
Chloramine Species with pH
Monochloramine
o pH range of 8 to 8.5
Chloramine Optimization Technology
Mini ChemScan• Colorimetric Analyzer• Single Parameter
UV Series ChemScan • Spectrometer Analyzer• 4 to 8 Parameters• 1 to 2 Sample Locations
Potable Water Applications ChemScan Model Raw Surface Water Monitoring mini UV254, Fe, Mn, LowAmPermanganate Dosing/Pink Water mini‐Mn or UV 2150Settled Water Analysis mini Poly, UV254 or ColorDeep Bed Carbon Breakthrough UV‐3150 ( UV‐toc or Color)Groundwater Systems mini Mn, FE, oP UV254Aeration Oxidation towers mini Fe, Mn or UV2150/FMRO or Ion Exchange skids UV 3150/6101 ‐ 2150/FMMembrane Breakthrough & Cleaning UV 3150 or mini UV254Nitrate Monitoring & Well Blending UV 3150 w 4‐8 linesPressure Filters w Carbon for Organics UV 3150 w UV‐tocFe /Mn Pre‐Oxidation UV2150/FM or mini MNColor, UV%T & Organics Measurement mini UV254 or UV 3150WTP Peak Point Chloramination UV 2150/S or UV6101Distribution System Chlorine Boost UV 2150/S or miniFree/MonoNitrification Monitoring in Tanks UV 2150 –NO2 wetchemAlgae /MIB/ Geosmin at Intakes UV 3150 or mini UV 254Filter Backwash DeChlor mini Sulf or LowChlorCorrosion Control (ortho/poly blends) mini‐oP or mini Copper
ChemScan Control Parameters
Free Ammonia as N
Total Ammonia as N
Monochloramine as Cl2
Dichloramine as Cl2
Total Chlorine as Cl2
Nitrate as N
Nitrite as N
% Transmittance
Organic Correlation (TOC, NOM, DOC)
ChemScan Analysis Methods
Primary Multi-Wavelength UV Absorbance
o Monochloramine, Nitrate, Nitrite, %T and Organics
Secondary Multi-Wavelength Absorbance
o Free Ammonia (Bleach, NaOH and EDTA)
o Total Ammonia (Bleach and Acid)
o Monochloramine (Potassium Iodide)
o Total Chlorine (Potassium Iodide and Acid)
ChemScan Benign Reagents
Sodium Hydroxide (NSF Std 60 Certified)
Sodium Hypochlorite (NSF Std 60 Certified)
Sulfuric Acid (NSF Std 60 Certified)
Potassium Iodide
Hydrochloric Acid (NSF Std 60 Certified)
Multiple reagent bid proposals
Typical ChemScan Chloramination Analyzer Configurations
Ratiometric Control (CL2:N)o Free NH3-N, Monochloramine, Total NH3-N and Total Cl2
Residual Control o Free NH3-N and UV-254 nm %T
o Free NH3-N, Monochloramine, Total Cl2 and NOM
Distribution Monitoring
o Free NH3-N, Total NH3-N, Monochloramine, Total Cl2
o Free NH3-N, Monochloramine, Total Cl2 and NO2-N
o Free NH3-N, Total NH3-N, Monochloramine, Total Cl2, and NO2-N (UV-6101)
o Free NH3-N, Total NH3-N, Monochloramine, Total Cl2, NO2-N and Spectral Deviation (UV-6101)
ChemScan Schematic Photodiode Detector
o 3 minutes ammonia samples
o 1 minute flush
o 4 minutes chlorine samples
The York Water Company
31.6 MGD Surface Water Plant
Population of 192,000
65,000 Service Connections
48 municipalities
YORK
Why Use Chloramines?
Less DBP formation
Secondary Disinfectant
Residual Lasts Longer
When Dosed Properly, Tastes
and Smells Better
Two Projects
WTP Optimization of Chloramine Formation
Rechloramination Station
Project Goals for Both were the Same:
Chloramine Optimization
Maximize Monochloramines
Prevent Nitrification (minimize free ammonia)
Improve Water Quality
Water Treatment Plant
Optimization
o Chloramine Control
o Control Strategies
o Breakpoint Curve
o How we Control Chemical
Dosing
Chloramination Control Strategies
Ratiometric control
o Cl2 : NH3-N ratio between 3:1 and 5:1
o Measures total chlorine from all forms and total
ammonia from all forms (free and combined)
Residual control
o Maintain small free ammonia residual
o Maintain target monochloramine
Water Treatment Plant OptimizationChemScan UV Series Spectrometer• Optimize Chloramine Dosing & Control• East & West Plant Effluent (2 Locations)
o Free Ammoniao Total Ammoniao Monochloramineo Total Chlorine
From Multimedia Filters
East & WestEffluent Sample
Chloramination Breakpoint Curve (Fixed Ammonia)
Optimal Chloramine Control Range
Two Residual and Dosing Scenarios
First Example: Optimal Total Chlorine = 2.0 mg/L
Monochloramine = 1.9 mg/L
Total Ammonia = 0.44 mg/L
Free Ammonia =0.03 mg/L
Operational Checklist: 4.5 : 1 ratio (TCl2 : TNH3)? = check
Mono ~95% of Total Cl2 = check
Free Ammonia < 0.1 mg/L = check
Two Residual and Dosing Scenarios
Second Example: High Free NH3 Total Chlorine = 2.0 mg/L
Monochloramine = 1.3 mg/L
Total Ammonia = 0.62 mg/L
Free Ammonia =0.22 mg/L
Operational Checklist 4.5 : 1 ratio (TCl2 : TNH3)? = NO
Mono ~95% of Total Cl2 = NO
Free Ammonia < 0.1 mg/L = NO
Two Residual and Dosing Scenarios Second Example: High Free NH3
Total Chlorine = 2.0 mg/L
Monochloramine = 1.3 mg/L
Total Ammonia = 0.62 mg/L
Free Ammonia =0.20 mg/L
What Now??
Increase Cl2 dose by 0.8-mg/L = Yes – 4.5 : ratio restored and
Free NH3 < 0.1
-OR-
Decrease NH3 dose by 0.17 mg/L = Yes – 4.5 : 1 ratio & Free
NH3 < 0.1
The Distribution System
Distribution Nitrification
Control
Higher Chloramine residual
Higher Cl2 : NH3-N ratio
Periodic chlorine shocks
Higher turnover in reservoirs
System flushing
Monitoring at strategic locations
Distribution System Optimization
2.0 MG Standpipe• Passive Mixing System
12’ x 20’ Pre-Engineered Structure• Chloramine Booster Station
Distribution System Optimization
ChemScan UV Series Spectrometer• Re-Chloramination Station• Tank Outlet Pipe• Pre & Post Chemical Feed Sample
(2 Locations)o Free Ammoniao Total Ammoniao Monochloramineo Total Chlorine
Distribution System Optimization
SodiumHypochlorite
Chemical Storage VentilationAmmonium Sulfate
Distribution System Optimization
Chase WaterPumps
SCADA-Pack PLC
Eyewash Station
Remote SCADA View-Only
Items to Consider With Chemical Booster Station Construction Why is there never time to do it
right the first time, but there is always time to do it over?
Thank you to: Pete Lusardi, GHD
Marty Strine, The YWC Superintendent M&G and his team!!
Scott Kirby Joe Shaeffer
Evan Sterner
Kevin Krueger
Items to Consider With Chemical Booster Station Construction Plan Ahead!
Communicate: learn from others and learn from past Involve all groups early:
Instrumentation
Electrical & Mechanical
Water Quality
Operations
Engineering
Project Manager or “Champion”
Lists of what is needed: Ask questions
Group discussions
If this – then that
What can we do better? Flow switches and meters
Conduits
Chaser
Ease of Maint.
Items to Consider With Chemical Booster Station Construction Permits: PADEP + local
Site: Own, lease, right-of-way, electrical service, drainage, accessibility, chemical deliveries
Chemicals: clean, organized, ventilation, safety, double wall tanks, mixing, chase-water, injectors, pace-to-flow
SCADA: dosing control & analysis feedback, chase-flow, alarms and set-points
Conduits: to and from vaults and sampling points – comms, sample, injection, power
Everything must fit (through the doors!) and in the available space
Thank You
Questions?
Source: Optimizing Chloramine Treatment, AWWA Research Foundation, 1993
Douglas Crawshaw
Water Quality Manager
York Water Company
130 E. Market St., Box 15089
York, PA 17405
(717) 718-2974
Christopher A. Evans, P.E.
Regional Sales Engineer
Kershner Environmental Technologies
724 S. 11th Street
Philadelphia, PA 19147
215-668-1746
