How to use polyacrylamide？

Polyacrylamide is a flocculant widely used in water treatment, papermaking, mining and other sectors. Can the correct use of polyacrylamide improve water treatment efficiency and reduce costs? Today, we will provide a detailed guide on how to use polyacrylamide.


 

Polyacrylamide must be prepared as a 0.1–0.3% aqueous solution before use. Direct addition of PAM powder is strictly prohibited. Clean tap water must be used for dissolution, and the water temperature must be strictly maintained at room temperature. Add the powder evenly and stir continuously for 40–60 minutes until the solution is completely clear and transparent.
 

1. Dissolution

It is recommended to use water with a neutral pH and low hardness for dissolving polyacrylamide. Avoid using wastewater, strong acids, strong alkalis, water at high temperatures, or water with high salt content. Add the powder evenly and maintain a moderate stirring speed. Avoid prolonged vigorous stirring, as this may cause the solution to degrade.

The dissolution time is typically 30–60 minutes. For polyacrylamide powder, the solution will perform at its best if used one hour after dissolution. The dissolved solution must be used up on the same day. Do not allow the solution to stand for more than 24 hours, as the polyacrylamide solution will degrade rapidly, thereby affecting its performance. During the dissolution process, ensure that the flow rate of the automatic dosing system is not too high to prevent the formation of lumps in the polyacrylamide.

2. Concentration Ratios

The typical dissolution concentration for cationic PAM is 0.2%. For anionic and non-ionic types, the dissolution concentration is 0.1%. If the on-site chemical dissolution tank is small but the dosage is high, the prepared concentration may become excessively high. When the molecular weight of polyacrylamide is high, a slightly lower concentration should be used. The concentration of the prepared solution should not be too high. If the polymer concentration is too high, it will increase the agitation load. This may result in poor dispersion of the chemical and uneven mixing with the wastewater, thereby affecting the water treatment efficacy.

3. Dosage

Polyacrylamide can be dosed using a metering pump. The dosage should be adjusted according to the actual wastewater treatment process and water quality conditions. During dosing, care should be taken to avoid impact and shear, so as not to affect the stability and efficacy of the solution.

4. Mixing

Polyacrylamide must be thoroughly mixed with water prior to dosing. Ensure it is evenly dispersed. Furthermore, if used in conjunction with other chemicals, this should be done to achieve optimal water treatment results.

5. Monitoring

Following dosing, water quality parameters such as COD and BOD should be monitored regularly to enable timely adjustments to the dosage and water treatment process.