Precautions for the use of polyacrylamide flocculant:
1, the size of the floc: the floc is too small will affect the speed of drainage, the floc is too large to bind more water and reduce the mud biscuit degree. The size of the floc can be adjusted by selecting the molecular weight of the polyacrylamide.
2. Sludge characteristics. First understand the source, characteristics and composition of sludge, the proportion. According to the different properties, sludge can be divided into organic and inorganic sludge two kinds. Cationic polyacrylamide is used for the disposal of organic sludge, the relative anionic polyacrylamide flocculant is used for inorganic sludge, cationic polyacrylamide is used when the alkali is very strong, and anionic polyacrylamide is not suitable when the acid is very strong, and the amount of polyacrylamide is usually large when the solid content of the sludge.
3, floc strength: floc under shearing should adhere to stability and not broken. Improving the molecular weight of polyacrylamide or selecting suitable molecular structure is helpful to improve the stability of flocs.
4, the ionic degree of polyacrylamide: for dehydrated sludge, flocculants with different ionic degrees can be selected after a small test to stop, select the appropriate polyacrylamide, so that you can obtain a good flocculant effect, but also make the dosage of less, save money.
5, the dissolution of polyacrylamide: good dissolution can give full play to the flocculation. Sometimes it is necessary to speed up the dissolution rate, at which time the concentration of the polyacrylamide solution can be adjusted.
(1) Can polyacrylamide and polyaluminum chloride be used simultaneously
In fact, in the usual sewage treatment, some sewage, the use of a single flocculant is not effective, must be used in combination with the two, the use of inorganic flocculant PAC and polyacrylamide composite flocculant treatment of sewage will achieve better results, but when adding agents to pay attention to the order, the order is not correct, but also can not achieve the effect.
Polyacrylamide and other flocculants are mixed to add sequential methods:
In the use of composite flocculants must pay attention to the order of addition and dosing time interval! The combined use of PAC and PAM is to make PAC complete the neutralization of charge/colloid instability to form a small floc, and further increase the floc volume is conducive to full precipitation. Because the reaction time of polyaluminum chloride PAC is very short, it needs strong mixing after joining, the PAM action time is long, and the mixing attention is strong after weak – the first strong is to mix evenly after weak is to avoid damaging the floc! Polyacrylamide is a flocculant, polyaluminum chloride is a coagulant, under normal circumstances is to add coagulant and then add polyacrylamide, but for the sake of insurance, it is recommended that we determine the order of addition through the experimental effect! Dosing point, dosing amount, dosing time and mixing strength need to be determined experimentally, remember that they must not be used together, otherwise it will affect the effect and increase the cost of use.
