Jar Test Presentation

By

Douglas Rittmann, Ph.D., P.E.Water/Wastewater Consultant

To

UTEP Lab Class

On

March 21, 2006

Purpose of Jar Test

1. Evaluate and control Coagulation, Flocculation and Sedimentation

A. Used in New Plant Design of Flash mixing, Flocculators, Sedimentation units

B. Used in Existing Plant operations to evaluate coagulants, & polymers.

C. Evaluate changes in raw water quality from turbidity levels, pH, temperature.

D. Evaluate changes from coagulant dosages, pH ranges, mixing energy,settling times, type of coagulant, and mixing times.

Jar Text Apparatus

1 or 2 liter jars

RPM indicator

Stirring Paddles

RPM control

Materials & Reagents

1. Variable Speed (0 -100 rpm) stirring machine with 6 paddles

2. Six 1 liter or 2 liter beakers

3. Large container to collect samples

4. Several 1,5, and 10 ml pipettes graduated in 0.1 ml.

5. Stock solution of chemicals (coagulant, polymer, acid or caustic)

Procedure

1. Number Beakers; shake sample thoroughly; Add 1 or 2 l per beaker

2. Place beakers under mixers and set stirring rpms at 100 rpm

3. Add progressive amounts of stock solution chemicals to each beakerto cover the range of chemical dosage expected for proper treatment.

4. Mix the chemicals at 100 rpm for 3 minutes or less according to plant’sflash mixer design specifications

5. After flash mixing period, reduce mixing to 40 rpm or plant flocculator’s design specifications

6. After 20 minutes or flocculator detention period, turn off mixing

7. After settling for 30 minutes or according to calibrated plant condition.

8. Observe floc size, settling rate and record test results.

Coagulation Test Record

Questions