Polyelectrolyte dosing guide
How much Sunfloc to dose, how strong to make the solution and how to turn mg/L into kilograms a day.
Typical starting doses
These are starting points from water and effluent treatment practice. Your own jar test sets the final dose.
| Water or effluent | Anionic grades | Cationic grades |
|---|---|---|
| Clean, low turbidity (below 20 NTU) | 0.1 – 0.3 mg/L | 0.2 – 0.5 mg/L |
| Moderate turbidity (20 – 100 NTU) | 0.2 – 0.8 mg/L | 0.5 – 1.5 mg/L |
| High turbidity (above 100 NTU) | 0.5 – 1.5 mg/L | 1 – 3 mg/L |
| Industrial effluent (ETP, CETP, STP) | 0.5 – 3 mg/L | 1 – 5 mg/L |
Working out kilograms per day
Kilograms of polymer per day = flow in m³/day × dose in mg/L ÷ 1000. For example, a 500 m³/day plant dosing 1 mg/L uses 0.5 kg of polymer a day, or about 15 kg a month. The dosing calculator does this for you, including pump rate.
Solution strength
Dose polymer as a dilute solution, never as dry powder. A make-up strength of 0.1 to 0.5% (1 to 5 g/L) suits most plants. Do not exceed the grade's maximum use concentration: 5 g/L for most grades and 10 g/L for Cationic HQ. Each HQ grade also lists a recommended working concentration on its page.
Making it up
- Fill the tank with about 80% of the water and start the stirrer.
- Sprinkle the granules slowly into the vortex so they do not form lumps.
- Keep mixing gently for 45–60 minutes until fully dissolved, then top up.
- Use the solution within a day. Made-up polymer loses strength if kept longer.
Where to dose
Add the polymer after the coagulant, where mixing is gentle but thorough. Added into a rapid mixer, the flocs are sheared apart; added too late, the polymer does not mix in.
Sludge dewatering
For presses and centrifuges, dose is usually expressed as kilograms of polymer per tonne of dry solids. Screen grades on fresh sludge with a beaker and sieve test, then trial the best two on the machine. See sludge dewatering.
Related
Polyelectrolyte dosing guide
Starting doses, solution strength and how to work out kilograms per day.
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