Transcript Beta Template Light 1 - PNWS-AWWA

Jar Testing Machines –
Not Just for Making High
End Martinis Anymore
Robin Lee, P.E.
Agenda
Background Questions
History
Modern Day
Mechanics
Benefits of jar testing
AWWA Spring Conference 2008
Background Questions
 How many people have done a
jar test?
 How many people do routine jar
tests?
 Why or why not?
–Not trained.
–Time consuming.
–Don’t understand how to
interpret results.
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AWWA Spring Conference 2008
Goal of Today’s Presentation
 Debunk the numerous
reasons/excuses for not performing jar
test.
 Show jar test value (other than just
stirring martinis).
 Prove that jar tests are not that hard.
 Illustrate the many reasons why jar
tests should be done.
 And of course, have a little fun....
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Why Martinis?!?
 The methods to make martinis has
been around since 1887 and remain
relatively the same, however—
 The ingredients have changed!
 AND WE STILL DRINK MARTINIS!
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How Martinis are Similar to Jar Tests
 The methods to conduct a jar test date
back to 1920s and have stayed relatively
the same...
 BUT the ingredients and concepts have
changed!
Old Concepts
New Concepts
Metal Salts
ACH/PACL
Polymers
Manufactured polymers
Turbidity
Total organic carbon
Standard pH
pH Adjustment
Multiple tests
ChemTrac
 Not grandpa’s recipe anymore!!
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History
 First jar test run on the Sacramento in
the 1920s
 Similar design and methods used today
 Used to be conducted on regular basis....
As much as once per week!
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Modern Day
 Many plants rely on the same
chemicals and focus more on
changing dosages and not
chemicals
 New employees do not have
“hands on experience” with water
chemistry
 Many jar test machines collect
dust
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AWWA Spring Conference 2008
Mechanics
How to run a jar test
Calibration
How to interpret
results
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How to Run a Jar Test – Select Chemicals
and Doses
 What has been used in the past
 Try new coagulants, coagulant
aids, and/or filter aids
 Research new manufactured
polymers
 Test a variety of
coagulants using
Chemtrac to determine
how they work on
raw water
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How to Run a Jar Test – Interpreting
Chemtrac Results
-
Charge
Optimum dose range
is where charge
decreases most
drastically
+
Dose
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How to Run a Jar Test – Run Test
 Fill 6 jars with raw water
 Prepare chemical dosages
 Determine Mixing Times/Energy by
mimicking plant
 Example Mixing Scheme
–1 min 295 rpm (rapid)
–5 minute 100 rpm
–5 min 60 rpm
–5 minute 30 rpm
–Settle for 30 minutes
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How to Run a Jar Test - Calibration
Settling
Flocculation
Stage 1
100 s-1
Stage 2
60 s-1
Stage 3
30 s-1
Add filter aids
Filtration
Add
polymers/coagulants
Add coagulant
aids
Rapid Mix
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AWWA Spring Conference 2008
How to Run a Jar Test – Determining
Mixing Scheme
Graph Created by: Camp, 2930s
500
400
300
G, s-1
200
100
Find energy from plant
80
60
Then determine mixing
speed from graph
50
40
30
20
10
10 20
30
40
50
60 70
80
Speed, rpm
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90
100
200
How to Run a Jar Test – Interpretation
 Create record keeping sheet
 Record chemicals and dosages
 Watch for floc formation time and
type
–Haze
–Pin
–Heavy
 “Best physical floc”
 Record filtered water TOC and
turbidity
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How to Run a Jar Test – Filterability Test
 Sample all or best floc sample
 Filter sample (0.45 µ)
 Test for turbidity and TOC in
settled water and filtered water
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Flow Chart of Procedures
Start with
routine dosing
scheme
(between
10-30mg/L
Run
Test
Inspect each
jar for best
physical
appearance
of floc
Is there a
good floc
formation?
YES
Filter and test
sample for
turbidity and
TOC
NO
Try new
coagulant dose,
coagulant aid, or
pH adjustment
NO
Optimize until exact dose is determined
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Did the
coagulant
decrease TOC
& turbidity?
YES
Optimize
dosing
scheme by a
few mg/L.
Why Jar Test
 React to changing water
conditions and standards
 Optimize coagulation
 Best water quality
 Use less chemicals
 Save money
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AWWA Spring Conference 2008
The Benefits Shown Graphically
$
Turbidity
Cost
Savings
$
Dose
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Let’s Review Today’s Message
 You are now trained to run a jar
test.
 Jar tests may be time
consuming, but considering the
benefits or money and water
quality, it is small price to pay.
 You should now understand
how to interpret results, it can
even be qualitative.
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Questions
AWWA Spring Conference 2008