在目前的研究中,提供了有关氧沉降厌氧(OSA)中剩余污泥最小化机制的见解。调查涉及两个并行操作的系统。特别是,考虑了常规的活性污泥(CAS)系统作为控制,并考虑了实施OSA工艺的系统,该系统均具有预反硝化方案。研究了五个周期(P1-P5),在此期间,测试了几种操作条件和配置。具体来说,OSA系统厌氧反应器中的水力停留时间(HRT)(P18h,P2-P312小时,P48小时,P512h)和从厌氧到缺氧(方案A)(P1-P2)或好氧(方案B)主流反应器(P3-P5)的回流污泥进行了研究。结果表明,OSA中的剩余污泥产量在所有配置中均较低(12-41%)。更详细地说,在OSA工艺中,观察到的产量(Yobs)从0.50-0.89gTSSgCOD-1(对照)降低到0.22-0.34gTSSgCOD-1。当OSA根据方案B操作并且在厌氧反应器(P3)中HRT为12小时时,实现了最高的剩余污泥减少(40%)。一般来说,方案A能够建立细胞裂解和胞外聚合物(EPS)破坏,当施加高厌氧HRT(>8小时)时,导致工艺性能恶化。相比之下,方案B除了解偶联代谢之外,还能够建立维持代谢,而细胞裂解和EPS破坏最小化。这允许在不损害流出物质量的情况下获得更高的污泥减少产率。
In the present research, insights about the mechanisms of excess sludge minimization occurring in an oxic-settling-anaerobic (OSA) were provided. The investigation involved two systems operating in parallel. In particular, a conventional activated sludge (CAS) system as control and a system implementing the OSA process both having a pre-denitrification scheme were considered. Five periods (P1-P5) were studied, during which several operating conditions and configurations were tested. Specifically, the hydraulic retention time (HRT) in the anaerobic reactor of the OSA system (P1 8 h, P2-P3 12 h, P4 8 h, P5 12 h) and the return sludge from the anaerobic to the anoxic (scheme A) (P1-P2) or aerobic (scheme B) mainstream reactors (P3-P5) were investigated. The results highlighted that the excess sludge production in the OSA was lower in all the configurations (12-41%). In more detail, the observed yield (Yobs) was reduced from 0.50-0.89 gTSS gCOD-1 (control) to 0.22 -0.34 gTSS gCOD-1 in the OSA process. The highest excess sludge reduction (40%) was achieved when the OSA was operated according to scheme B and HRT of 12 h in the anaerobic reactor (P3). Generally, scheme A enabled the establishment of cell lysis and extracellular polymeric substances (EPS) destructuration, leading to a worsening of process performances when high anaerobic HRT (>8 h) was imposed. In contrast, scheme B enabled the establishment of maintenance metabolism in addition to the uncoupling metabolism, while cell lysis and EPS destruction were minimized. This allowed obtaining higher sludge reduction yield without compromising the effluent quality.