The standard jar test is a critical procedure for selecting the appropriate polymer for a aparticular clarification application. This procedure allows individual polymers to be compared on such criteria as floc formation, settling characteristics, and clarity. Generally, the best performing products provide fast floc formation, rapid settling rate, and clear supernatant. This test should be performed on-site, since large amounts of water may be required for testing.
To save time, prepare the polymer test solutions , between 12 and 24 hours in advance.
|Desired ppm ------>||0.25||0.5||1.0||2.0||3.0||5.0||10||20|
Check the total alkalinity and pH of the water to be tested. Water containing an alkalinity of at least 25 mg/L and pH of 7.0 will coagulate without adding alkaline salts. Color, as opposed to turbidity can often be removed by lowering the pH as far as 6.0, by using alum or an acid. Values higher than pH 7 may be helpful in removing manganese, while still forming a floc.
* Attempt to mimic actual system conditions.
The floc formed in the Jar Test can be further evaluated using this procedure. This method is also used for primary and secondary clarifiers and sludge thickeners. Performance in this test is evaluated on floc settling rate, sludge volume, and clarity of supernatant.
|Desired ppm ---------->||0.25||0.5||1.0||2.0||3.0||5.0||10||20|