Misunderstandings in the selection of polyacrylamide for water treatment

There are mainly three types of polyacrylamide: anionic, cationic, and non-ionic. Anionic polyacrylamide is suitable for sewage flocculation, sedimentation, dewatering, clarification, etc., and can also be used for dehydration of inorganic sludge. Cationic polyacrylamide is suitable for flocculation, sedimentation, decolorization and clarification of complex water, as well as dewatering of municipal sludge and organic sludge. Nonionic polyacrylamide is suitable for soil water retention, weak acid sewage flocculation, sedimentation, dehydration, etc.

1. Misunderstanding 1: The larger the molecular weight of polyacrylamide, the higher the flocculation efficiency and the better the effect.

There are dozens of types of polyacrylamide. The sewage produced by different enterprises is different: acidic water, alkaline water, neutral water, oilycolored, and some contain a lot of organic matter or a lot of sedimentsetc. It is necessary to select models through experiments and then do on-site tests to determine the optimal dosage, so as to achieve the goal ofless dosage, best result and low cost”.

2. Misunderstanding 2: The higher the ionicity, the better.

Ionicity refers to the negative and positive nature of the ionic charge of this chemical reagent, as well as its charge density. The higher the ionicity, the smaller the molecular weight. At the same time, the higher the ionicity, the higher the price of the product. The ionicity has an effect on the compactness and water content of the flocculation of the product. Further tests are necessary in the selection process to determine the suitable polyacrylamide type.

3. Misunderstanding 3: The longer the stirring and dissolving time of polyacrylamide (PAM) , the better.

The appearance of polyacrylamide is white crystalline particles, generally between 20-80 mesh. It should be fully dissolved during use. Generally, the  stirring and dissolving time should not be less than 30 minutes. As the temperature is low in winter, the stirring and dissolution time should be extended.

4. Misunderstanding 4: The higher the concentration of polyacrylamide (PAM), the better its flocculation.

The concentration of polyacrylamide is generally 0.1%-0.3%, which is suitable for flocculation and sedimentation (depending on the molecular weight of PAM or the speed of sedimentation). When dewatering urban and industrial sludge, the concentration is between 0.2% and 0.5% (the concentration needs to be adjusted according to the sludge concentration).

The concentration of PAM  depends entirely on the concentration of sewage and sludge. When the sewage is of high impurity, the concentration of polyacrylamide should be increased. However, the concentration is not the higher the better. The reasonable dosage of PAM must be determined through experiments before used on site.

As one of top ten polyacrylamide manufacturers in China, Shandong Welldone can provide you with cationic, anionic and nonionic polyacrylamide, which could be used in various fields, including oil and gas, municipal and industrial water treatment, mining, paper and sugar industries. If you are interested, please feel free to contact us:jack.ma@welldonechina.com