进水中碳水化合物分子大小对污泥沉降性能的影响

为弄清楚碳水化合物分子大小和污泥沉降性能之间的影响关系,在3个序批式系统中,分别以颗粒型淀粉、溶解型淀粉和葡萄糖为碳源,考察了长期运行中系统的污泥沉降性能和处理能力.结果证明:碳水化合物分子越小,活性污泥对环境的变化越敏感,当运行条件不利时越容易引发污泥膨胀问题;大分子碳源吸附于絮体内部能够提高污泥的沉降性能;糖类作碳源时,活性污泥的PHA贮存量约为0.6mmol C/L,但系统SVI仍然能够维持在150mL/g以下;胞外聚合物中多糖与蛋白质(C/P)的比值与污泥的SVI呈正相关性,SVI从100mL/g增长到600mL/g,C/P比从0.248增长到1.201;以颗粒型淀粉、溶解型淀粉和葡萄糖为碳源时,系统的优势丝状菌分别为Type 0041、M. parvicella和S. natans;进水以葡萄糖作单一碳源时,系统的除磷能力能达到80%以上.

Effect of influent carbohydrates with different molecule-size on sludge settleability

It’s still unclear whether the sludge settleability would be affected by the molecule-sizes of carbohydrates. In order to reveal this correlations, long term effects of influent carbohydrates with different molecule-size on sludge settleability were investigated in this study. Three lab-scale sequencing batch reactors were operated by using particulate starch, soluble starch and glucose as the solo carbon source, respectively. The smaller the carbohydrate molecule-size was, the more sensitive the activated sludge was with the environment changing. Therefore, the system would be more easily to suffer with bulking problems when feeding with micro-molecule carbohydrate. The adsorbed particulate carbohydrate would highly increase the sludge settleability in the polymeric carbohydrate-fed system. The SVI was kept lower than 150mL/g in the glucose-fed system although the PHA production was only about 0.6mmol C/L. The carbohydrate to protein (C/P) ratio of the extracellular polymeric substances showed positive correlation with SVI. The C/P value increased from 0.248to 1.201while the SVI increased from 100to 600mL/g. The dominant filamentous bacteria of the particulate starch-, soluble starch- and glucose-fed system were Type 0041、M. parvicella and S. natans, respectively. Finally, the phosphorous removal efficiency could reach to 80% with glucose as the sole carbon source.