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Research and application status and development trend of PAM in wastewater treatment plant
It has been found that there are more than 17 kinds of wastewater treatment plants, which are more than kinds of bacteria, bacteria, actinomycetes and yeast. There are many produced from the same wastewater treatment plant with polyacrylamide (PAM), one of the most representative for the following three:. Nakamura polyacrylamide PAMAJ7002 Aspergillus Aspergillussouae) production; Takagi h. with Paecilomyces ((Paecilomycessp. I - 1) sewage factory production of polyacrylamide PAMPF101; researchers by Rhodococcus erythropolis (Rhodococcuserythropolis) developed sewage plant polyacrylamide PAMNOC-1.
Sewage treatment plant PAM by anionic polyacrylamide polymer composition. Therefore, in nature with organic anion polyacrylamide PAM similar, its flocculation properties, mechanisms, effects are with organic anion polyacrylamide PAM is similar, but it has own characteristics. Wastewater treatment plant (PAM) is a natural non-toxic organic high molecular compound, including the function of the protein and functional polysaccharide, so sewage plant polyacrylamide PAM has unique properties of biodegradable, and on the environment and human are nontoxic. Sewage plant polyacrylamide PAM has a high thermal stability, the C-62 strain produced by polyacrylamide PAM after boiling for 10 minutes and its activity is still 88%. The PAM of the wastewater treatment plant has a good coagulation ability for many kinds of flocculation particles as well as the synthesis of high molecular weight PAM.
(1) bridging flocculation mechanism the mechanism of that PAM with ionic bonds, hydrogen bonds, and in combination with the multiple particle molecules, play a "bridge" role between the particles, so that the formation of suspended matter reticular structure of flocs and settling down. Normally think of synthetic high polymer polyacrylamide (PAM) are generated by this mechanism of flocculation, mechanism of sewage plant polyacrylamide PAM flocculating mechanism and synthesis of polyacrylamide PAM is consistent. This mechanism is most recognized by people.
(2) the electrical and mechanism the mechanism that the surface of colloidal particles with negative charge, when with a positive charge of chainlike biological macromolecular polyacrylamide (PAM) or its hydrolysis products near the particles, and colloidal surface charge, electrostatic repulsion is reduced, so that the particles between magnetic collision and cohesion, to the solution of adding metal ions or adjusting the pH value can influence the flocculation effect.
(3) the mechanism of chemical reaction is that the reaction of some active groups in biological macromolecules with the corresponding groups of the reacting substances, and then the larger molecules and precipitation down. By modification of the biological macromolecule, it is added or lost some active groups, and the flocculation activity is changed. Some scholars have pointed out that the activity of PAM is mainly dependent on the active group, that is, the activity of the active group determines the activity of PAM.
(4) volume scanning mechanism this mechanisms that, when wastewater treatment plant (PAM) of a certain dosage and the formation of small flocs, in under the action of gravity, rapid capture, sweep water particle volume, to produce precipitation. This effect can be regarded as a mechanical action. Practice has proved that the required amount of PAM and impurity in water suspension concentration is proportional to the. The molecular weight, molecular structure, molecular structure and the molecular structure of the polyacrylamide PAM have an effect on the activity of PAM. Generally speaking, higher molecular weights, higher flocculating activity; high linear molecular flocculating activity, molecular branched or crosslinked more, the worse the flocculation of; polyacrylamide (PAM) producing bacteria in the late culture, enhance the cell surface hydrophobicity, produced by PAM activity is also more and more high. The surface structure and charge of the colloidal ion in the treatment of the water body are also influenced by the charge. Some reports pointed out that water cations, especially Ca2 + and Mg2 + can reduce the negative charge on the surface of colloid, promote the formation of the "bridge". In addition, the presence of high concentrations of Ca2+ can also protect the role of polyacrylamide PAM from degradation enzymes.
Sewage plant polyacrylamide PAM flocculation range is wide, the flocculating activity was high, and conditions of extensive, mostly from the influence of ionic strength, pH value and temperature, so you can widely applied in sewage and industrial wastewater treatment. Livestock wastewater livestock wastewater with high BOD, difficult processing, the synthesis of high molecular polyacrylamide (PAM) effect is not good, and use or handling of swine manure wastewater is the effect is very good, after 10 min treatment. The supernatant was nearly transparent, the TDC by 8200mg/L drop 2980mg/L. OD value decreased from 157 85. Decolorization of wastewater? In ink, paper making black liquor, molasses wastewater, pigment in colored water and wastewater join or, flocculation and sedimentation solid-liquid separation after, the decolorization of wastewater, the effect is obvious. Sludge bulking. Sludge bulking is difficult to settlement, so it is difficult to deal with, such as the processing of licorice wastewater will produce sludge bulking, or added, the SVI quickly from 290 down to 50, eliminating the sludge bulking, restoration of the activated sludge settling ability. Tanning industrial wastewater in leather wastewater join c-62 strains of polyacrylamide (PAM), the turbidity removal rate of up to 96%. Ceramics factory wastewater? The wastewater mainly two kinds of green body wastewater and glaze wastewater, join or, 5 min after the turbidity of wastewater removal rate 96.65% and 97.9% respectively, almost transparent in the supernatant.