污泥停留时间对单级好氧生物除磷的影响

Effect of sludge retention time on phosphorus removal in aerobic /extended-idle regime

以丙酸钠为单一碳源,设置4组不同污泥停留时间(SRT)的SBR(R1:SRT=9 d;R2:SRT=12 d;R3:SRT=18 d;R4:SRT=24 d),考察SRT对单级好氧生物除磷的影响。实验结果表明,当SRT分别为9、12、18和24 d时除磷效率分别为34.2%、85.0%、93.3%和76.7%,单位VSS除磷量分别为1.97、4.62、4.70和3.59 mg-P/g-VSS,SVI分别稳定在89、93、98和123 mL/g左右。随着SRT增大,系统除磷效率及单位VSS除磷量先升高后下降,并在SRT=18 d时达到最大值,而污泥沉降性能逐渐变差。分析各组反应器中内聚物的变化表明,R1中的微生物在外源基质消耗阶段利用糖原质的分解合成多β羟基烷酸盐(PHA),但PHA消耗阶段没有磷酸盐的大量吸收,表现出聚糖菌的代谢方式;R2、R3和R4中的微生物在外源基质消耗阶段通过TCA循环合成PHA,在PHA消耗阶段大量合成聚磷,表现出聚磷菌的代谢方式。

Sodium propionate was adopted as the sole carbon source,and four sequencing batch reactors(SBR) with four sludge retention times(SRT. R1: 9 d; R2: 12 d; R3: 18 d; R4: 24 d) were introduced to study the effect of SRT on biological phosphorus removal in aerobic /extended-idle regime. In the process of operation in four SBRs,the phosphorus removal efficiencies were 34. 2%,85. 0%,93. 3% and 76. 7%,the phosphorus removal rate per uint VSS were 1. 97,4. 62,4. 70,3. 59 mg-P /g-VSS,and the SVI were averagely 89,93,98,123 mL /g,respectively. Experimental results showed that with increasing SRT,the phosphorus removal efficiency and removal rate per uint VSS first rose and then descended,and reached a maximum at a critical SRT of 18 d,while the settling performance of sludge stepped down. According to the changes of intracellular polymers in SBRs,microorganism synthesised poly-β-hydroxyalkanoates(PHA) using glycogen at the stage of exogenous substrates consumption in R1,while there didn't exist substantial absorption of phosphate at the stage of PHA consumption,which indicated a metabolic way of GAOs; in R2,R3 and R4,microorganism synthesised PHA using TCA at the stage of exogenous substrates consumption,and synthesised large amount of Poly-P at the stage of PHA consumption,which implied a metabolic way of PAOs.