Polyacrylamide can be divided into anionic, cationic, nonionic and amphoteric according to ionic properties. According to molecular weight, there are many models derived from different specifications of molecular weight and ionicity. Facing the confusing specification system in the market, how to solve the common problems of sewage or sludge polyacrylamide selection? 1. Understand the source of sludge. First of all, we should understand the source, nature, composition and solid content of sludge. Sludge can be divided into organic sludge and inorganic sludge. Generally speaking, cationic polyacrylamide Flocculant is used to treat organic sludge, and anionic polyacrylamide Flocculant is used to treat inorganic sludge. When the sludge solid content is high, the dosage of polyacrylamide is usually larger.
2. Polyacrylamide ionicity selection (1) For the sludge to be dewatered, different ionicity Flocculants can be screened through small experiments, and the selection of suitable polyacrylamide can achieve good flocculation effect, reduce the dosage and save the cost. (2) Floc strength improve the molecular weight of polyacrylamide helps to improve floc stability.
(3)The viscosity of polyacrylamide solution is related to its molecular weight and preparation concentration. The polyacrylamide must react fully with the sludge at a certain position in the dewatering equipment and flocculation occurs. Therefore, the viscosity of the polyacrylamide solution must be suitable to be able to mix with the sludge sufficiently under the existing equipment conditions, and whether it is evenly mixed is a key factor for success.
(4) Increase the concentration of polyacrylamide solution, fully dissolved to play a good flocculation.
3.Selection of molecular weight of polyacrylamide The molecular weight of polyacrylamide is the length of the molecular chain in the molecule. Between 500-18 million. The higher the molecular weight, the higher the viscosity of the polyacrylamide product. The viscosity of the polyacrylamide solution increases with the molecular weight of the Polymers, which is due to the fact that the viscosity of the Polymer solution is caused by the interactions between the molecules during molecular movement. In use, the appropriate molecular weight of polyacrylamide should be determined according to the actual application industry, water quality, treatment equipment and other conditions.
The molecular weight should not be too high for sludge dewatering using belt filter press. If the molecular weight is high, the filter cloth may be clogged, affecting the dewatering effect; if the centrifugal filter press is used, the requirement of molecular weight will be higher, because the centrifugal filter press requires the floc to be as shear-resistant as possible, so it is necessary to choose the product with relatively high molecular weight.
