Key points for Selection and Use of Polymer Flocculants in Sludge Treatment
In the process of sludge treatment we do not only need the equipment such as decanter centrifuge
but also need flocculanats. It's very important to select and make good use the right polymer flocculant, otherwise the result of sludge treatment will not be ideal. Here are some key points from GN Separation about the selection and use of polymer flocculants:
① Selection of species: The action mechanism of flocculants is charge neutralization polymer bridge, so anionic and cationic flocculants should be selected according to the charge characteristics of the separated materials.
② Selection of dosage: The best dosage of flocculant is that the flocculant is completely adsorbed on the surface of the solid phase particles and the flocculation sedimentation speed reaches the maximum. When the flocculant exceeds the optimal amount, the flocculation effect will decrease.
③ Selection of molecular weight: The larger the molecular weight of the flocculant, the stronger the capture power of solid particles, and the better the flocculation effect. If the molecular weight of the flocculant is too small. No flocculation effect will be achieved. For sludge dewatering, the selected molecular weight must be ≥ 3 million.
④ Shear strength of flocculant: Flocculants used in belt filter presses and decanter centrifuges
have different shear strength requirements. High for general decanter centrifuges. And in the small sample test, you need to use a stirrer to verify the intensity of different stirring.
⑤ Selection of the feeding position; after flocculant is added, the flocculation settling speed is faster. If it is transported through a long-distance pipeline, it will easily cause pipeline blockage. According to tests, it is best to dissolve the flocculant solution with good solubility. Add at the decanter centrifuge inlet
⑥ Dissolving method of flocculant: High-speed mechanical stirrer cannot be used to dissolve the polymer flocculant, because the strong mechanical stirring will destroy the molecular chain of the flocculant, and the effect of the flocculant will be significantly reduced. Generally, the stirring speed of the dissolving flocculant is less than 50 rpm, and it is appropriate to divide it. The blade of the mixer should be as wide as possible. Studies have shown that the flocculant is 0.4 to 0 after being added to water. 6MPa compressed air bubbling is the best method to dissolve the flocculant-the dissolution is very uniform and the dissolution rate is extremely fast.
We hope the key points above can be helpful to the clients in treatment of sludge. GN can not only provide users with Decanter Centrifuges, but also provide users with turnkey solutions for dewatering process, including solutions for material transportation, classification and dewatering. Rely on GN’s rich production line of separation and conveying equipment, more and more reliable and advanced equipment will be manufactured for users all over the world.