Department of Civil & Environmental Engineering, University of Utah, Salt Lake City, USA.
Civil Engineering Department, Shanghai Science & Technology, China.
Water Res. 2014 Apr 15;53:153-67. doi: 10.1016/j.watres.2013.12.035. Epub 2014 Jan 11.
Solids reduction in activated sludge processes (ASP) at source using process manipulation has been researched widely over the last two-decades. However, the absence of nutrient removal component, lack of understanding on the organic carbon, and limited information on key microbial community in solids minimizing ASP preclude the widespread acceptance of sludge minimizing processes. In this manuscript, we report simultaneous solids reduction through anaerobiosis along with nitrogen and phosphorus removals. The manuscript also reports carbon mass balance using stable isotope of carbon, microbial ecology of nitrifiers and polyphosphate accumulating organisms (PAOs). Two laboratory scale reactors were operated in anaerobic-aerobic-anoxic (A(2)O) mode. One reactor was run in the standard mode (hereafter called the control-SBR) simulating conventional A(2)O type of activated sludge process and the second reactor was run in the sludge minimizing mode (called the modified-SBR). Unlike other research efforts where the sludge minimizing reactor was maintained at nearly infinite solids retention time (SRT). To sustain the efficient nutrient removal, the modified-SBR in this research was operated at a very small solids yield rather than at infinite SRT. Both reactors showed consistent NH3-N, phosphorus and COD removals over a period of 263 days. Both reactors also showed active denitrification during the anoxic phase even if there was no organic carbon source available during this phase, suggesting the presence of denitrifying PAOs (DNPAOs). The observed solids yield in the modified-SBR was 60% less than the observed solids yield in the control-SBR. Specific oxygen uptake rate (SOUR) for the modified-SBR was almost 44% more than the control-SBR under identical feeding conditions, but was nearly the same for both reactors under fasting conditions. The modified-SBR showed greater diversity of ammonia oxidizing bacteria and PAOs compared to the control-SBR. The diversity of PAOs in the modified-SBR was even more interesting in which case novel clades of Candidatus Accumulibacter phosphatis (CAP), an uncultured but widely found PAOs, were found.
在过去的二十年中，人们广泛研究了在活性污泥工艺（ASP）源头通过工艺控制实现固体减量化。然而，由于缺乏养分去除组件、对有机碳的理解不足以及关于固体最小化 ASP 中关键微生物群落的信息有限，限制了污泥最小化工艺的广泛应用。在本文中，我们报告了通过厌氧和好氧-缺氧（A(2)O）同时实现固体减量化以及氮磷去除。本文还报告了使用稳定同位素碳、硝化菌和聚磷菌（PAO）的微生物生态学进行碳质量平衡。两个实验室规模的反应器以厌氧-好氧-缺氧（A(2)O）模式运行。一个反应器以标准模式运行（以下称为对照 SBR），模拟传统的 A(2)O 型活性污泥工艺，第二个反应器以污泥最小化模式运行（称为改良 SBR）。与其他研究工作不同，污泥最小化反应器的固体停留时间（SRT）几乎是无限的。为了维持高效的养分去除，本研究中的改良 SBR 以非常小的固体产率运行，而不是无限的 SRT。两个反应器在 263 天的时间内都表现出一致的 NH3-N、磷和 COD 去除效果。两个反应器在缺氧阶段也表现出有效的反硝化作用，即使在该阶段没有有机碳源，这表明存在反硝化聚磷菌（DNPAOs）。改良 SBR 的观察到的固体产率比对照 SBR 低 60%。在相同的进料条件下，改良 SBR 的比需氧量（SOUR）比对照 SBR 高 44%，但在饥饿条件下，两个反应器的 SOUR 几乎相同。改良 SBR 显示出比对照 SBR 更高的氨氧化细菌和 PAO 的多样性。改良 SBR 中 PAO 的多样性更有趣，其中发现了新型未培养的聚磷菌（PAO）候选累积磷菌（Candidatus Accumulibacter phosphatis，CAP）的新分支。
Indian J Environ Health. 2001-4
Biotechnol Bioeng. 2003-7-20
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