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CONDUCT OF JAR TESTS AND THE IMPORTANT INFORMATION OBTAINED

Jar testing traditionally has been done on a routine basis in most water treatment plants to control the coagulant dose. Much more information, however, can be obtained with only a small modification in the conventional method of jar testing. It is the quickest and most economical way to obtain good reliable data on the many variables which affect the treatment process. These include:

  1. Determination of most effective coagulant.
  2. Determination of optimum coagulation pH for the various coagulants.
  3. Evaluation of most effective polymers.
  4. Optimum point of application of polymers in treatment train.
  5. Optimum sequence of application of coagulants, polymers and pH adjustment chemicals.
  6. Best flocculation time.
  7. Optimum energy input.
  8. Acceptable energy input taper.
  9. Obtaining data for preparation of settling velocity distributing curves.
  10. Amount of turbidity going to the filters and effect on filter performance.
  11. Evaluating results of sludge recycle.
  12. Determining safe and reliable loading for conventional settling basins.
  13. Determining design criteria for basin loading both conventional and high rate with tubes or plates.
  14. Evaluating the possibility of direct filtration.
  15. Tolerable velocities between flocculation and settling units.

The engineers of Water and Air Research, Inc. have applied jar test data in the design of new plants, the upgrading and expansion of existing plants and improvement of performance of a wide variety of plants throughout the world. The data has been found to be very economical to obtain and reliable to use.