Jar Testing Machines – Not Just for Making High End Martinis Anymore Robin Lee, P.E

Jar Testing Machines – Not Just for Making

High End Martinis Anymore

Robin Lee, P.E.

AWWA Spring Conference 2008

Agenda

Background Questions

HistoryModern DayMechanicsBenefits of jar testing

AWWA Spring Conference 2008AWWA 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.


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....


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!


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!!


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!


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


Mechanics

How to run a jar test

CalibrationHow to interpret results


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


How to Run a Jar Test – Interpreting Chemtrac Results

Dose

Charge

Optimum dose range is where charge decreases most

drastically

-

+


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


How to Run a Jar Test - Calibration

Stage 1 Stage 2 Stage 3

100 s-1 60 s-1 30 s-1

Flocculation Settling

Filtration

Rapid MixAdd coagulant aids

Add polymers/coagulants

Add filter aids


How to Run a Jar Test – Determining Mixing Scheme

10 20 30 40 50 60 70 80 90 100 200

Speed, rpm

500

400

300

200

100

80

60

50

40

30

20

10

G, s-1

Find energy from plant

Then determine mixing speed from graph

Graph Created by: Camp, 2930s


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


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


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

NO

Try new coagulant dose, coagulant aid, or pH adjustment

Filter and test sample for

turbidity and TOC

NO

YES

Did the coagulant

decrease TOC & turbidity?

Optimize dosing

scheme by a few mg/L.

Optimize until exact dose is determined


Why Jar Test

React to changing water conditions and standards

Optimize coagulation

Best water qualityUse less chemicalsSave money


The Benefits Shown Graphically

$

Dose

Turbidity

$Cost Savings


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.


Questions

Documents

Jar Testing Machines – Not Just for Making High End Martinis Anymore Robin Lee, P.E