Gradient reduced aeration in an enhanced aerobic granular sludge process optimizes the dominant microbial community and its function
Gradient reduced aeration in an enhanced aerobic granular sludge process optimizes the dominant microbial community and its function
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DOI：
10.1039/c7ew00562h
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
Z. Zhiming;Zhuodong Yu;Liang Zhu;Hai-tian Yu;X. Dai;Xiang-yang Xu;P. Alvarez
中科院分区：
文献类型：
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作者：
Z. Zhiming;Zhuodong Yu;Liang Zhu;Hai-tian Yu;X. Dai;Xiang-yang Xu;P. Alvarez
采用一种新型节能曝气策略，采用实验室规模的好氧污泥法处理城市污水。为了比较，两种调节策略（直接减少曝气和逐渐减少曝气）并行操作。结果表明，在饥饿期采用减少通气的操作策略导致能量消耗显著降低（p < 0.01）。当直接还原曝气时，大部分好氧污泥被冲洗出来，颗粒污泥不可逆地解体; MLSS从6.33 g L−1逐渐下降到1.94 g L−1，SVI达到325 mL g−1。同时，zeta电位和污泥产量分别从-17.3 mV和1.13 kg MLSS/kg COD上升到-20.7 mV和1.96 kg MLSS/kg COD。NH 4 +-N、TN和COD的去除率分别下降到61%、48%和82%。Leadbetterella spp.，属于鞘氨醇细菌门的细菌成为生物反应器中的优势微生物。而采用梯度减量曝气策略时，Shannon多样性指数显著提高（p < 0.01），好氧颗粒结构保持稳定，保持了好氧污泥的丰富性和多样性。FISH结果表明，功能微生物如动胶菌属的富集。EPS分泌物富集在颗粒污泥的内部。双向电泳结果表明，在梯度减压通气条件下，稳定颗粒中富集了4种分泌EPS的胞外蛋白质PPIase、焦磷酸磷酸水解酶、OprF和OMP。因此，本研究为调控好氧颗粒污泥的结构稳定性提供了一种科学的方法。
The laboratory-scale aerobic sludge process was used to treat municipal sewage using a novel energy-saving aeration strategy. For comparison, two strategies of regulation (reducing the aeration directly and reducing the aeration gradually) were operated in parallel. Results showed that using an operation strategy with reduced aeration during the famine period led to a significant reduction of energy consumption (p < 0.01). Much of the aerobic sludge was washed out and granular sludge disintegrated irreversibly when the direct reduction of aeration was applied; the MLSS dropped gradually from 6.33 g L−1 to 1.94 g L−1 and the SVI reached 325 mL g−1. At the same time, the zeta potential and sludge yield rose from −17.3 mV and 1.13 kg MLSS per kg COD to −20.7 mV and 1.96 kg MLSS per kg COD, respectively. The removal efficiency of NH4+-N, TN and COD decreased to 61%, 48% and 82%, respectively. Leadbetterella spp., which belongs to the phylum Sphingobacteria, became the dominant microorganism in the bioreactor. By contrast, when the gradient reduced aeration strategy was applied, Shannon diversity indices increased significantly (p < 0.01) and the aerobic granular structure remained stable, revealing that the richness and diversity of the aerobic sludge were retained. FISH results revealed that the enrichment of functional microorganisms such as Zoogloea spp. for EPS secretion enriched in the inner part of the granular sludge. Results of 2-DE demonstrated that four extracellular proteins PPIase, pyrophosphate phosphohydrolase, OprF and OMP, which can secrete EPS, were enriched in the stable granules under the condition of gradient reduced aeration. Therefore, a scientific method to regulate the structural stability of the aerobic granular sludge was achieved in this study.