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Problems
Noted by
Water
Systems Using
NH2Cl
•Low NH2Cl
Residuals
•Nitrification
•Growth of
Slime
Bacteria
Chloramination and
Nitrification
Study
Lake City Florida
Chloramination/Nitirification Study
Some Questions to be
Answered with this Study
Chloramination
&
Nitrification
Study
Characteristic
Pink Color of
the Presence
of Chlorine
Residual
1. What concentrations of NH2Cl are necessary
in the distribution system to maintain
acceptable residual?
2. What are the water quality process control
indicators and optimal ranges to ensure
adequacy of NH2Cl residual?
3. How significant are affects of mixing of water
from storage tanks on distribution system
NH2Cl residual?
4. What simple, readily available and low cost
sampling methods can be used to predict
NH2Cl decay and pre-nitrification conditions?
Identifying Low NH2Cl Residual
in the Distribution System
Issue:
Poor
Turnover in
Tanks can
Result in
Disinfectant
Degradation
and to
Nitrification
inside
Storage
Tanks
• Areas with High
Water Age
• Storage Tanks that
not Fully Cycle
do
Elevated Tank #2
• Areas with Very Low Customer Use or at
Periphery of the Water Distribution System
• Areas with Restricted Flow
• Dead End Pipelines
• Known Tuberculated or Biogrowth Pipeline
Areas
Skeletonized Lake City
Water System
Objective:
Establish
Reasonable
Flow
Distribution
Using a
Skeletonized
Approach to
Estimate
Flow and
Water Age
in System
61 PSI
84 PSI
120
PSI
76 PSI
Monthly Water Demand 2007
Mo
.
Putnam WTP
Peak GPM
Putnam WTP
Ave GPM
Price Crk.
Peak GPM
Price Crk.
Ave GPM
Objective:
1
3075000
2891000
Determine
Representative
Flow
Distribution
During Time
Period that
Sampling will
take place
2
3677000
3109000
3
4318000
3480000
4
4870000
3983000
5
4518000
4047000
6
4379000
3831000
7
4304000
3758000
8
9
4369000
3845000
Peak Flow
4290000
2813000
10
2459000
1742000
1473000
1430000
11
1570000
1327000
1764000
1430000
12
1570000
1327000
1981000
1430000
Use 6.5 MGD
Base Flow
Use of a
Simplified
Hydraulic
Model
The
Equivalent
Pipe Method
Can be Used
to Develop a
Simplified
Hydraulic
Model for
Identifying
Water Age
Simplified Hydraulic
Profile for 6.5 MGD Flow
#
Pipe Description
Equivalent
Length
1.
20” pipeline from WTP to US 90
West of I-75
111,082 feet
2.
12” pipeline from WTP to CR
245 @ US 90
15,495 feet
3.
10” pipeline from CR245 @ US
90 to 12” @ Putnam St and
Montrose Street POE
45,623 feet
4.
10” Pipeline from CR245 North
then easterly to 8” crossing
under US90 at NE Center Ave
31,320 feet
Allocate Flows and
Identify Low NH2Cl Areas
Allocation
of
Demand
Flows can
be
allocated
based on
reasonable
hydraulic
conditions,
i.e. friction
and
velocity
Restricted Flow &
High Demand Area
Low NH2Cl
Area
1200 GPM
800 GPM
2500 GPM
Sampling Results for NH2CL
Degradation Identification
July 09, 2008
NH2Cl Results
FH 1
FH 2
FH 3
FH 4
FH 6
FH 8
Equiv 12”
2.4 mg/l
2.4 mg/l
2.0 mg/l
0.5 mg/l
0.8 mg/l
2.1 mg/l
10”
FH 2
Storage Tank #1
FH 1
FH 3
16”
FH
51
Low
Price
Creek
WTP
FH 6
FH 4
Storage Tank #2
FH 8
Putnam WTP
8”
Preliminary Temperature Findings
July 28, 2008
Temp Results
FH 2
FH 3
FH 51
FH 52
FH 53
77.5 Fo
80.1 Fo
82.5 Fo
85.5 Fo
85.7 Fo
Use of
Temperature
Water Temp
shows
Excellent
Correlation
with NH2Cl
Residual
• Simplified Hydraulic Model Provides Fairly Good
Indicator of Flows
• Hydraulic Constrictions Adversely Affect Central
City NH2Cl Residuals
• Water Storage Tanks are Likely Contributors to
NH2Cl Degradation

Check Temperature along Route from
Price Creek WTP to Storage Tank #1
Storage
Tank #1
FH 53
Price Creek
WTP
FH 52
FH 51
FH 3
FH 2
Tank Discharge Effect on
NH2Cl Residual July 9 - 22
Storage Tank
Information
Tanks Full
146.0
Tanks Empty
128.0
Tank Full
145
Tank 1
140
Tank 2
135
NH2Cl= 0.5 m g/l
Dow ntow n
Area
130
125
120
9
10
11
14
Tank
Low
High
Tank
Low
High
1
128.1
143.5
2
129.9
143.5
NH2Cl = 0.5 mg/l
Elevated Tanks 1 &2
Findings:
• Tanks
Operate in
Tandem
• Tanks
adversely
affect NH2Cl
Residual
NH2Cl = 0.1 mg/l
150
Tank 1
145
Tank 2
140
135
Tank
Low
High
Tank
Low
High
NH2Cl = 0.1 m g/l
1000' S. Tank 1
130
125
17 18
21
22
Elevated Tanks 1 &2
1
134.2
141.7
2
138.5
145.7
Comparing NH2Cl Sampling
and Analysis Methods
Desired
Components
Simple
Accurate
Reproducible
Precise
•
•
•
•
•
•
Use of the Titrimetric FES Method
Use of a Hach DR 5000 *
Use of a Hach DR 890 *
Use of Test Strips
Use of an ORP Meter
Use of OTO
* Test for Total and Monochloramine
Comparing Chloramine
Test Methods
Bias
Precision
Accuracy
• Accuracy – the closeness of
the measured value to the
true value
• Bias – Consistent deviation
from the true value
• Precision – Measure of the
Degree of agreement among
samples
Brief Review of
Chloramine Production
Measuring
Chloramine
Under typical
WTP conditions
only Combined
Chlorine is
produced
Total Chlorine =
Free Chlorine +
Combined Chlorine
0
TC = CC + FC
Monochloromine
Dichloromine
Cl2 Dose
>10:1
NH3
Addition
DPD Ferrous Titration
Standard Methods 4500 Cl F
SM 4500 Cl F
DPD Ferrous
Titrimetric
Method
• 5 mg/l ea.
DPD reagents
• 2 drops of KI
• Mix
• Allow 2 min.
• Titrate with
FAS
• Read as mg/l
Total Chlorine
• This method is used in
most WTP Laboratories
• Advantage is that testing
is quick and results are
accurate
• Titrations are very simple
to perform and give a result
in total chlorine (monochloramine +
dichloramine)
• Differentiation of chloramine species is
also relatively easy to perform
DR 5000
Benefits
Use of Hach DR-5000
Spectrophotometer
• Versatile Laboratory
Instrument that is a
complete water quality
•Provides full
laboratory
spectrum of
• Uses premixed packets or “pillows”
Ammonia
Series
• Tests are very simple to perform and give a
•Allows
results in total chlorine (monochloramine +
analysis of TOC
dichloramine)
, UV 254 and
SUVA
• Differentiation of chloramine species
•Allows for
(monochloramine) is also easy to perform
TTHM
analysis
• Provides Ammonia presence in same test
procedure
•Allows for
speciation of
Chloramine
Use of Hach DR-890 Series
Hand Held Colorimeter
DR 890
Testing
•Prepare
Blank (zero
mg/l)
•Add
Powdered
Reagent
•Allow
Reaction
Time
•Read
Results in
mg/l
• Colorimeter is Used by
Most Operators
• Uses Prepared packets
or “pillows”
• Very Portable and capable of performing
a wide variety of chemical tests
• These include Free Chlorine, Total
Chlorine, Monochloramine, and
Ammonia, Nitrite and Nitrate
Use of Test Strips
Test Strip
Procedure
•Dip Strip in
Sample
•Allow
Reaction Time
•Compare
Strip to Color
Comparator
Provided
•Read as mg/l
• This method is widely used in
Tropical Fish Industry
• Chloramines and Ammonia
Compounds are Very
Toxic to Ornamental Fish
• Methods have been perfected to allow for accurate
Analysis Using Inexpensive Test Strips in waters
containing other compounds
• Objective: Compare Testing Accuracy of Various
Low Cost Test Strips to more Precise Analysis
Provided by more Typical Water Analysis Methods
Use of Test Strips for
NH2Cl Identification
Use of
Test Strips
Provide Good
Correlation to
NH2Cl
concentrations
for gross
indication and
precision
monitoring.
Usefulness
Gross
Accurate
Gross
NH2Cl
Lifeguard
Aquacheck
Water ID
2.0 mg/l
> 1.0 mg/l
2.0 mg/l
> 1 mg/l
1.5 mg/l
> 1.0 mg/l
1.2 – 1.75
> 1 mg/l
1.0 mg/l
0.5 – 1.0
1.0 mg/l
<1 mg/l
0.5 mg/l
0.25 – 0.5
0.5 – 0.75
> 0 mg/l
0.2 mg/l
0.1 – 0.25
0.1 – 0.4
> 0 mg/l
Use of Oxidation Reduction Potential
ORP Testing
• Testing Must
be Performed
in-place since
Oxygen and
Temp change
ORP reading
• No Reagents
are Required
•Instrument is
Inexpensive
~ $100 and easy
to Use
• mv reading
must be
converted to
mg/l NH2Cl
Oxidation Potential of NH2Cl
Courtesy Hach Company
Generalized ORP with NH2Cl
over Wide Range of Conditions
• Oxidation Reduction Potential (ORP) is Used for
Controlling Free Chlorine (Oxidant) Addition in the Water
Industry
• Chloramine is a Weaker Oxidant than Free Chlorine that
also can be measured with ORP (millivolt potential)
• ORP can Provide a “Signature” of NH2Cl Decay
• The ORP Signature can also Provide Status of Nitrification
Reactions are occurring in the Water System
Pinpoint
ORP (mv)
Comparing ORP Samples for Estimating
Surrogate NH2Cl Concentrations
Std Read
240 240
470 453
No Correlation for
Samples Transported to
Lab
Use of ORP
Appears to
Provide Good
Correlation to
NH2Cl for
Samples
Tested
inplace
ORP vs NH2Cl
for Testing In-Place
1
387 mv
6
4
2
0
NH2Cl
(mg/l)
1
2
389 mv
3
399 mv
4
415 mv
5
426 mv
2
3
4
5
ORP
(mv)
Sam ple Num ber
Good Correlation
Sampling In-Place
OTO
Procedure
Use of Orthotolidine OTO
•Fill to 5 ml
•Add 5 drops
of Reagent
• Shake
Sample
andWait 10
Seconds
• Compare
Color to
Comparator
Provided
•Read as mg/l
• pH change is
additional
indicator of
Water
Conditions
• This method is widely used in
Swimming Pool Industry
• Combined Chlorine Residual
and pH is easily identified by
Color Comparator Test
• Reagents are Commercially Available and Test
is very Economical compared to any other
Testing Method
• Accuracy is Very Good over a Wide Range of
Total Chlorine Values
Comparison of OTO & Test
Strips for NH2Cl Identification
Use of
OTO
Provide Gross
Correlation to
NH2Cl poor
for precision
monitoring.
Field Sampling Comparisons to DR 890
Test Strip
OTO
2.2 mg/l
> 2.0 mg/l
1.0 – 1.5
2.0 mg/l
2.0 mg/l
1.0 – 1.5
1.2 mg/l
1.0 mg/l
1.0 – 1.5
0.7 mg/l
0.6 mg/l
0.4 mg/l
0.1 mg/l
0
0
NH2Cl
Comparing Nitrification* Indicators
Sampling and Analysis Methods
Desired
Components
Accurate
Reproducible
Simple
Meaningful
•
•
•
•
Use of a Hach DR 5000
Use of a Hach DR 890
Use of Hach Titrimetric Test Kit
Use of Test Strips
* Sampling for NH3, NO2 and NO3
Determination of NO3 & NO2 in
Source Water & Distribution Sys.
Field Sampling DR 890, Nitrivar 5 (0 – 5.0 mg/l)
Location
NO3
NO2
Price Crk
0.8 mg/l
0
FH #3
0.7 mg/l
0
FH #50
0.9 mg/l
0
FH #51
0 mg/l
0
FH #52
trace
0
Status Report for August
Chloramination/Nitrification Study
Tasks Completed
• Hydraulic Network
Established
• Low NH2Cl Areas
Identified
• Tank/NH2Cl Affects
Identified
• Effective NH2Cl
Monitoring Methods
Identified
Future Tasks
• Continue Nitrogen
Series Identification
• Compare Nitrogen
Methods
• Perform Biological
(HPC) Monitoring
• Recommend
Solutions
• Complete Final
Report