A thin layer of similar colloidal residues and some large flocs are left on the inner wall and bottom of the dissolving tank in many sewage treatment plants. No matter how long the residues are stirred or stirred, it is difficult to dissolve them again. If they are not properly treated, it will often cause some unnecessary small troubles, and these residues also want to be a big trouble when cleaning, some large flocs The coagulant can also be taken out with hooks and the like. The biggest fear is that some small flocs flow into the drug feeding pipe and block the dosing pump.
Polyacrylamide is an organic polymer flocculant with large molecular weight, generally in millions or tens of millions. When it is dissolved, it will swell first, and then slowly dissolve. If the manual dosing method is adopted, the polyacrylamide added to water at one time has a large amount, and it can not be added evenly and slowly, the part of polyacrylamide that contacts water first will start to swell, and then it will be dissolved After that, the surface area becomes larger, and then the part not in contact with water is covered (you can peel the flocs out, and the middle is dry and not stained with water), so some insoluble polyacrylamide groups are formed. At present, most sewage treatment plants generally use manual dosing (if the automatic feeder is used, it can not only save manpower, but also avoid this situation as much as possible). It is suggested that the water should be stirred before dosing, and then slowly and evenly added above the water column flushed out of the water inlet, so that the reagent can be flushed into the water along the water flow, so as to reduce the probability of agglomeration. In addition, the contact between the reagent and the inner wall of the dissolving tank should be avoided as far as possible during dosing.
Suggestion: if conditions permit, the automatic continuous feeding system should be adopted as far as possible to improve the work efficiency and avoid agglomeration during dosing. In addition, the quality of polyacrylamide on the market is uneven. Some products have quality defects, such as poor hydrophilicity, more insoluble substances, poor solubility, etc., which are easy to agglomerate when adding drugs.