- Dry polymers are typically made down to 0.25% solutions by adding 0.5 grams of polymer to 200 mLs of water.
- Use the same water for laboratory solution preparation that will be used to prepare samples in actual plant situation.
- The recommended mixers for dry polymer are magnetic stirrer (with large 2 inch magnet), overhead mixer, twister mixer, or jar tester (gang stirrer). The jar tester allows 4 or 6 samples to be prepared at the same time but extreme care must be taken to thoroughly clean the unit after solution preparation to avoid contamination of your water samples in subsequent testing.
- Sprinkle the dry polymer into the vortex of the water slowly to avoid “fish-eyes” (10-15 seconds addition time).
- Continue mixing for 1 hour.
- Further dilution can now be done, if necessary, using the solution preparation procedure above.
- At room temperature cationic solutions are good for 6 hours while anionic solutions are good for 8 hours.
Dry polymers are water soluble, but certain precautions should be followed to obtain total dissolution with minimum loss of activity. Complete wetting of the individual polymer particles is the single most important factor in the preparation of dry polymer solutions. One recommended method of solution preparation is to fill the make down tank until the mixer blades are covered utilizing water in the range of 40-90º F. Begin agitation while continuing to add water. Disperse the polymer into the tank through either an aspirator type dispenser (eductor) or a vibrating chemical feeder. Fill the tank with water and continue agitation for approximately 60 minutes. Suggested make-down concentration is 0.1-0.5%. Subsequent dilution to 0.05 – 0.1% may improve product performance.
- Do not store samples in extreme temperatures.
- Adequate mixing is critical to ensure representative results, be sure sample container is well shaken and that mixing energy used to put product into solution is sufficient for the job.
- Always use a fresh syringe for each product. Do not clean and reuse syringes.
It is important to use the best water available to make your polymer solutions. Any solids in the make up water will react with the polymer rendering the solution less effective. Other water characteristics to consider are:
- pH – as the pH of the water becomes more alkaline the cationic products begin to lose effectiveness due to hydrolysis.
- Temperature – the recommended water temperature should be between 40-90º F. Temperatures below this range will typically result in slow or incomplete dissolution of the polymer. Temperatures appreciably above this range can cause hydrolysis of the polymers. In general, warm water allows for improved speed of dissolution and uncoiling but results in slightly shorter shelf life of the solution.
- Conductivity – waters that are very high in conductivity can inhibit the development of molecular weight in the polymer solution.