阴离子型聚丙烯酰胺相对分子质量和水解度对污泥脱水性能影响的研究

通过对污泥絮凝颗粒粒径分布、污泥比阻、泥饼含固率、上清液体积及其中核酸、蛋白质和总糖浓度的测定,研究了不同剂型和剂量阴离子型聚丙烯酰胺（PAM）对城市污泥沉降性能和脱水性能的影响及机制.结果表明,当PAM相对分子质量相同时,提高水解度能改善污泥的沉降和脱水性能;当PAM水解度相同时,提高相对分子质量亦可改善其沉降和脱水...

Effect of anionic polyacrylamide on settleability and dewaterability of sewage sludge

The effect of anionic polyacrylamide(PAM) with different molecular weight (MW) and hydrolysis degree(HD) on the settleability and dewaterability of sewage sludge was evaluated by determining the particle size distribution, specific filtration resistance and cake solid content of flocculated sludge as well as the supernatant volume, concentrations of DNA, protein and sugar in the supernatant of sewage sludge. Addition of anionic PAM increased the percentage of particles with diameter greater than 0.60mm, while decreased the percentage of particles with diameter less than 0.25mm. The increase in the HD of PAM with the same MW led to a rise of the supernatant volume, but a decline in the specific filtration resistance. For the PAM with the same HD, the supernatant volume increased with the MW increasing from 600 millions to 800 millions, but decreased with a further increase of MW to 1200 millions. The response of specific filtration resistance to the MW of anionic PAM was just opposite to that of supernatant volume. The effective application dosage of PAM on the settleability and dewaterability varied with the types of PAM. The optimal settleability and dewaterability was obtained at the dosage of 75 mgL-1 for the PAM with MW of 600 millions and HD of 30%, and for the PAM with MW of 800 millions and HD of 20%. It was also found that both the elevated HD of anionic PAM with the same MW and the elevated MW of anionic PAM with the same HD could induce an increasing concentration of protein and sugar in the supernatant of sewage sludge, implying that the release of extracellular polymeric substance (EPS) from the sludge surface was one of the main reasons for the improvement of settleability and dewaterability associated with PAM addition.