How to correctly choose polyacrylamide (PAM) model is an old problem, a common problem, and a problem that is easy to choose wrong. Picked the wrong one? What's the harm? There is basically no big harm, that is, the cost is increased or the flocculation effect is not as it should be, and the treatment is not up to standard. Of course, regardless of the size of the hazard, whether it is a hazard or to be avoided, it is also important to correctly select the right polyacrylamide (PAM) model.

The first step in correctly selecting polyacrylamide is to understand the major categories of PAM and the application direction of the major categories. Polyacrylamide can be divided into four types: anionic, cationic, non-ionic, and amphoteric. According to different specifications, molecular weight and ionization have derived many models. (Note: 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. Initially select the large type number of PAM from the function requirements:
　　
Anion: wastewater flocculation, precipitation, coagulation, coagulation and inorganic sludge dewatering, etc.; Cation: flocculation, sedimentation, decolorization of complex water bodies, dehydration of organic sludge, dehydration of urban sludge, etc.; Non-ionic: soil water retention, weak acid wastewater flocculation, settlement, dehydration, etc. In addition, in the dewatering of pressed sludge, cationic PAM should not be used for strong alkaline sludge, anionic PAM should not be used for strong acid sludge, and the amount of PAM used when the sludge solid content is very high.
　　
2. How to choose the model of cationic polyacrylamide:
　　
According to the properties of sludge, the most suitable ionization model can be selected for experimental tests using ionicity PAM. A simple beaker test site can be done, and the following aspects are observed and selected:
　　
Fc group size: too small floc will affect the speed of drainage, too large floc will make floc constrain more water and reduce the degree of mud biscuits. By selecting the molecular weight of polyacrylamide, the size of the floc can be adjusted. Flocculation moisture content: The floc should remain stable and not broken under the action of shear. The right molecular weight helps to improve the stability of the floc. Polyacrylamide and sludge are fully mixed, the two are mixed evenly, and the viscosity of polyacrylamide solution is related to its molecular weight and preparation concentration. Solubility: Good dissolution can give full play to flocculation. Sometimes it is necessary to speed up the dissolution, and 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 greater the viscosity, however, when used, it is not the higher the molecular weight of the product, the better the use effect, specifically in use, it is necessary to choose the appropriate molecular weight of polyacrylamide according to the actual application industry, water quality, treatment equipment and other conditions.
　　
The specific methods are:
　　
1. Take at least 100 ml of raw sewage water from the beaker and take 3-5 pieces respectively.
　　
2. After diluting and dissolving polyacrylamide products with different molecular weights, add them to the beaker respectively and correspond to the labels.
　　
3. Under normal circumstances, dissolve and stir first, and the dosage and dosage are the same.
　　
4. Observe the reaction after several beakers are added, the precipitation rate, the size of the floc, etc. Select the two samples that best handle them.
　　
5. Compare between the two, add drugs separately, when the same treatment effect is achieved, measure the dosage of the molecular weight of the two types of polyacrylamide, the less the dosage, the better the effect.
　　
Summary
　　
Because the water quality and sludge properties of each sewage plant are different, so there are certain differences in the choice of polyacrylamide models, it is best to carry out experimental tests before choosing polyacrylamide, and then operate the test to determine which ionization or molecular weight polyacrylamide model is more suitable for use, on the one hand, it can reduce the cost of use, on the other hand, it can strengthen the use effect.