The correct way to choose polyacrylamide (PAM) model

How to correctly choose the polyacrylamide (PAM) model? This is an old problem, it is also a common problem, and it is also a problem that is easy to choose wrong. Wrong choice? What's the harm? There is basically no major harm, that is, the cost is increased or the due flocculation effect is not achieved, and the treatment is not up to the standard. Of course, regardless of the size of the hazard, the hazard must be avoided, the correct selection of the appropriate polyacrylamide (PAM) model is also important.

The first step in the correct choice of polyacrylamide is to understand the broad categories of PAM and the application directions of each category. Polyacrylamide can be divided into four categories: anionic, cationic, non-ionic, and amphoteric. According to different specifications of molecular weight and ion degree, many models are derived. (Note: It is not that the higher the price, the better, but the most important thing is to choose the one that suits you according to the water quality).

1. Preliminarily select the major type of PAM from the role requirements:

Anionic: wastewater flocculation, precipitation, coagulation aid, coagulation and inorganic sludge dehydration, etc.;

Cationic: flocculation, sedimentation, decolorization of complex water bodies, dewatering of organic sludge, dewatering of urban sludge, etc.;

Non-ionic: soil water retention, weakly acidic wastewater flocculation, sedimentation, dehydration, etc.

In addition, in the dewatering of pressed sludge, cationic PAM should not be used for strong alkaline sludge, and anionic PAM should not be used for strong acid sludge. When the solid content of the sludge is high, the amount of PAM used will be relatively large.

2. How to choose the model of cationic polyacrylamide:

According to the properties of the sludge, the most suitable ionization model can be selected for a small experiment with the ionization degree PAM. A simple beaker test can be done on-site, and observation and selection can be made through the following aspects:

The size of the floc group: too small a floc will affect the speed of drainage, too large a floc will restrict more water and reduce the degree of mud biscuit. After selecting the molecular weight of polyacrylamide, the size of the flocs can be adjusted.

Moisture content of flocs: The flocs should remain stable and not broken under shearing. The appropriate molecular weight helps to improve the stability of the flocs.

The polyacrylamide and the sludge are fully mixed, and the two are evenly mixed. The viscosity of the polyacrylamide solution is related to its molecular weight and preparation concentration.

Solubility: The flocculation function can be fully exerted only when it is dissolved well. Sometimes it is necessary to speed up the dissolution rate, then consider increasing the concentration of the polyacrylamide solution.

3. How to choose the model of anionic polyacrylamide:

Generally speaking, the higher the molecular weight of polyacrylamide, the higher the viscosity. However, when used, it is not the product with the higher the molecular weight. The better the effect will be. In the specific use, it needs to be based on the actual application industry, Water quality, treatment equipment and other conditions to select the appropriate molecular weight of polyacrylamide.

The specific method is:

1. Take at least 100 ml of raw sewage water in a beaker, and take 3-5 pieces respectively.

2. After diluting and dissolving the products with different molecular weights of polyacrylamide, add them to the beakers with corresponding labels.

3. Under normal circumstances, dissolve and stir first, and the dosage and dosage are the same.

4. Observe the reaction conditions after adding the medicine in several beakers, the precipitation speed, the size of the floccules, etc. Choose the two samples with the best treatment effect.

5. Compare the two and add the medicine separately. When the same treatment effect is achieved, measure the dosage of the two types of polyacrylamide molecular weight. The less the dosage, the better the effect.


Because each wastewater treatment plant has different water quality and sludge properties, there are certain differences in the selection of polyacrylamide models. It is best to conduct a small experiment before choosing polyacrylamide, and then operate the machine to determine which one needs to be used. Polyacrylamide models with ionicity or molecular weight are more suitable, on the one hand, it can reduce the cost of use, and on the other hand, it can enhance the use effect.

Post time: Mar-04-2021
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