Jar Testing Best Practices for Coagulants

Required Equipment

1. 2-Liter Square Jars

• A common misconception is that if you have round flocculation and settling units, you should use round jars. This is not the case. The operator should use jars that provide the best opportunity to predict the performance of the plant.

2. Paddle Gang Stirrer

• Can run at least two jars simultaneously at the same mix speeds.

3. Micropipette for Dosing

• Utilize the appropriate size micropipette to dose Coagulants, dose neat, as-is. 
• Note: Do not dose Coagulants from a solution, solutions can consume a portion of the reaction and provide skewed results.
• Calculation example to determine correct micropipette size: 
• Example for 10 ppm dose 
• 10 (ppm) * 2 (liter jar) / (Specific Gravity) 1.32 = 15.2 uL

Procedure

We recommend using a representative jar test procedure.

Representative jar testing means that the jar test procedure will imitate the coagulation, flocculation, and settling conducted in the water plant. There is no single jar test procedure that will replicate all these processes for all plants, however, experience shows that jar test procedures can be individually tailored to accurately predict performance for almost every plant. One way to confirm the procedure being used is accurate is to compare the current treatment programs dose is achieving the same settled turbidity in the jars as at the end of the settling stage, prior to filtration.

The resource to generate a representative procedure put together by the Texas Optimization Program can be found here.

For assistance, please reach out to USALCO anytime.