不同泥龄对活性污泥絮凝特性的影响

Effects of SRT on activated sludge bioflocculation

为了揭示不同污泥龄活性污泥的絮凝特性及作用机制,采用序批式反应器,考察污泥龄(solid retention time,SRT)对絮体EPS(extra-micro colony polymeric substances,EMPS)和菌胶团EPS(extra-cellular polymeric substances,ECPS)2种EPS组分的影响,通过扩展的DLVO理论和EPS组分解析不同污泥龄的絮凝性能。研究结果表明,随着SRT的增大,活性污泥的相互作用能曲线存在明显的势垒和势垒值逐渐减少,EMPS和ECPS含量逐渐减少,且相对于ECPS的变化,EMPS含量随泥龄的变化更加明显,其中蛋白质与腐殖质含量逐渐降低,污泥絮凝性能变好。这表明,较高的污泥相互作用能势垒和EMPS组分含量是污泥絮凝性能低的内在机制,且EMPS中蛋白质和腐殖质含量的变化是不同污泥龄污泥絮凝性能差异的主要原因。

This study investigated the bioflocculation characteristics and the mechanism of active sludge at differ- ent solid retention times （SRT）. Sequencing batch reactors with different solid retention times were employed to examine the influence of the bioflocculation characteristics and active sludge mechanism on the two components of EPS which contained flocs EPS （extra-microcolony polymeric substances, EMPS） and microcolony EPS （extra- cellular polymeric substances, ECPS）. By testing the extended DLVO theory and the EPS components, we ana- lyzed the biofloeculation characteristics and active sludge mechanisms at different SRT. The results showed that with the increase of SRT, bioflocculation characteristics of the active sludge improved. During this process, the interaction energy curve of the sludge had an obvious barrier that became lower in time. Meanwhile, the levels of EMPS and ECPS gradually decreased, showing that the changes in the EMPS content were more obvious than the changes in the ECPS content. The protein and humic substance content of EMPS gradually decreased as well, in- dicating that higher sludge interaction energy barrier and the EMPS content were the internal mechanisms of lower sludge flocculation. The change in the EMPS components, especially in protein and humic substance content of EMPS, was the main reason of diverse sludge bioflocculation at different SRT.