温度对生物强化除磷工艺反硝化除磷效果的影响

Effects of temperature on denitrifying phosphorus removal in enhanced biological phosphorus removal(EBPR) process

以处理城市污水的中试规模生物强化除磷A2/O活性污泥工艺系统为研究对象,考察了温度对系统COD去除和脱氮除磷效果的影响,特别是温度对活性污泥反硝化除磷性能的影响.结果表明,当温度从(30.9±0.8)℃降低到(9.1±0.6)℃时,A2/O系统的脱氮除磷效果显著下降,系统对TN和TP的污泥去除负荷明显下降.通过污泥反硝化除磷活性实验发现,随着温度的降低,系统中活性污泥的最大厌氧释磷速率、最大好氧吸磷速率和最大缺氧吸磷速率都降低.活性污泥中反硝化除磷菌(DPB)占聚磷菌(PAOs)总量的比例随温度降低稍有下降,但平均值仍维持在47.5%左右.用阿伦尼乌斯公式对实验结果进行拟合,得到系统中活性污泥聚磷菌厌氧释磷反应活化能Ea1为148.0kJ·mol-1,聚磷菌好氧吸磷反应活化能Ea2为228.8kJ·mol-1,发生在缺氧条件下反硝化除磷菌的吸磷反应活化能Ea3为315.8kJ·mol-1.对不同温度下污泥絮体粒径分析结果表明,随温度降低,粒径分布更加集中,系统中活性污泥絮体颗粒平均粒径减小,不利于污泥絮体内部反硝化除磷缺氧微环境的形成.

The effect of temperature on COD and nutrient removal,especially the denitrifying phosphorus removal was investigated in a pilot-scale anaerobic-anoxic-aerobic（A2/O） process for municipal wastewater treatment.The results indicated that temperature had a significant impact on the denitrifying phosphorus removal in the system.When temperature dropped gradually from（30.9±0.8） ℃ to（9.1±0.6） ℃,both the removal efficiencies and the sludge specific removal rates of TN and TP decreased.Meanwhile,the decrease of temperature lessened the maximum rates of phosphorus release,anoxic phosphorus uptake and aerobic phosphorus uptake of the activated sludge.As temperature declined,the ratio of denitrifying phosphorus removal activity to total phosphorus removal activity decreased slightly,but the average value remained at 47.5%.By applying Arrhenius equation,the activation energy values for anaerobic P release,anoxic P uptake and aerobic P uptake were calculated as 148.0 kJ · mol^-1,228.8 kJ · mol^-1 and 315.8 kJ · mol^-1,respectively.In addition,based on statistical analysis of particle diameter distribution in activated sludge under different temperatures,it was found that particle diameter distribution of activated sludge became more concentrated and the mean particle diameter of activated sludge flocs decreased with the drop of temperature.Lower temperature is unfavorable to denitrifying phosphorus removal due to less anoxic microenvironments in the activated sludge flocs.