Cationic flocculant has strong flocculation sedimentation effect on all kinds of suspended particles in an aqueous medium, especially for those colloidal solution particles with a negative charge which causes them to show with greater superiority.
Floccule size affects the rate of drainage: If the floccules are too small then the drainage is too slow; if the floccules are too large then the drainage is too fast making the floccules collect more water and reduce the size of the mud biscuit. You can adjust the size of the floccules by choosing the molecular weight of the cationic flocculant.
The first thing to understand the source, the characteristics ,composition of sludge and its proportion. According to the different properties, the sludge can be divided into two kinds : organic sludge and inorganic sludge. Cationic polyacrylamide is used for processing organic sludge, comparatively anionic polyacrylamide flocculant is used for inorganic sludge.You use anionic polyacrylamide when the sludge alkalinity is very strong and it is recommended to use anionic polyacrylamide flocculant when the acid-stage is very strong. Sludge with a high solid content usually has a large amount of polyacrylamide.
Floccules should be stable and chip-proof under shearing action. Increasing the molecular weight of cationic flocculanlant or choosing suitable molecular structure could enhance the stability of floccules.
For the dewatered sludge, you could use the flocculants with different ionic degree to make a small dose of experiment, selecting the most suitable polyacrylamide, therefore it can achieve the best effect of flocculant, in the meanwhile it also can make the least dosage and cost saving.
It could only give full play to flocculation by good dissolution. Sometimes you need to speed up the dissolution velocity, at this moment, trying to increase the concentration of the cationic flocculant solution.