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
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! Melon Ball Orange Drop Martini Cherry Bomb Chocolate Martini Sea Breeze Remy Side Car Saketini Blue Marlin Appletini Sweet and Spicy Dirty Executive Martini • 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 • Calibration • How 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 - Optimum dose range is where charge decreases most drastically Charge + Dose
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 Settling Flocculation Stage 1 Stage 2 Stage 3 100 s-1 60 s-1 30 s-1 Add filter aids Filtration Add polymers/coagulants Add coagulant aids Rapid Mix
How to Run a Jar Test – Determining Mixing Scheme Graph Created by: Camp, 2930s 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 • 20 30 40 50 60 70 80 90 100 200 • Speed, rpm
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 Inspect each jar for best physical appearance of floc Filter and test sample for turbidity and TOC Start with routine dosing scheme (between 10-30mg/L Is there a good floc formation? Run Test YES NO Did the coagulant decrease TOC & turbidity? NO Try new coagulant dose, coagulant aid, or pH adjustment YES 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 quality • Use less chemicals • Save money
The Benefits Shown Graphically Optimization Saves $$ $ Turbidity Cost Savings $ Dose
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.