SBR 中污泥中聚-β-羟基丁酸积累量对生物量浓度的依赖性。
Dependence of poly-β-hydroxybutyrate accumulation in sludge on biomass concentration in SBRs.
机构信息
Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom.
Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom.
出版信息
Sci Total Environ. 2021 Nov 25;797:149138. doi: 10.1016/j.scitotenv.2021.149138. Epub 2021 Jul 19.
The combination of wastewater treatment with polyhydroxyalkanoate production has attracted increasing interest in the context of the circular economy. Recent studies have thus attempted to optimize the conditions for polyhydroxyalkanoate accumulation in sludge when treating wastewater. The effects of biomass concentration and sludge morphologies in reactors on PHB storage, however, were neglected in the literature. Therefore, in this study settling time and organic loading rate were manipulated to adjust sludge morphology and biomass concentration in sequential batch reactors (SBRs) to investigate their influence on PHB storage in the feast phase. Our study shows that reducing settling times in SBRs from 10 to 0 min under organic loading rate of 3 g L d resulted in the decrease in biomass concentration at steady states from 4.2 to 1.0 g L and the change of sludge morphology from well-settled granules to poorly settled pinpoint flocs, but PHB content in sludge at the end of feast phase increased from 7.7 to 26.7%. The well-fitted regression lines between PHB content, SRT, feast/famine and food/microorganisms ratios and biomass concentration under different settling times suggest that PHB was highly dependent on biomass concentration but independent on sludge morphology. Under settling time of 0 min, the increase in OLR from 3 to 7.5 g L d resulted in an increased biomass concentration from 1.0 to 2.1 g L and an increase in PHB content from 26.7 to 33.8%. The batch and fed-batch experiments with different biomass concentrations also showed the influence of biomass concentration on PHB accumulation in sludge. The conclusion of the dependence of PHB content on biomass concentration under a fixed OLR and varied OLRs drawn from this study enables sludge PHB content as high as possible by adjusting biomass concentration in SBRs apart from the selective enriching strategies for PHB accumulating organisms when treating VFA-rich wastewater.
在循环经济背景下，将废水处理与聚羟基烷酸酯（PHA）生产相结合引起了越来越多的关注。最近的研究因此试图优化在处理废水时在污泥中积累 PHA 的条件。然而，文献中忽略了反应器中生物质浓度和污泥形态对 PHB 储存的影响。因此，在这项研究中，通过改变沉淀时间和有机负荷率来调整序批式反应器（SBR）中的污泥形态和生物质浓度，以研究它们在 feast 阶段对 PHB 储存的影响。我们的研究表明，在有机负荷率为 3 g L d 的情况下，将 SBR 中的沉淀时间从 10 分钟缩短至 0 分钟，导致稳态时生物质浓度从 4.2 g L 降低至 1.0 g L，污泥形态从沉降良好的颗粒变为沉降不良的针状絮体，但 feast 阶段结束时污泥中的 PHB 含量从 7.7%增加至 26.7%。在不同沉淀时间下，PHB 含量、SRT、饱食/饥饿和食物/微生物比与生物质浓度之间拟合良好的回归线表明，PHB 高度依赖于生物质浓度，而与污泥形态无关。在沉淀时间为 0 分钟的情况下，将 OLR 从 3 g L d 增加至 7.5 g L d，导致生物质浓度从 1.0 g L 增加至 2.1 g L，PHB 含量从 26.7%增加至 33.8%。不同生物质浓度的批式和补料分批实验也表明了生物质浓度对污泥中 PHB 积累的影响。从这项研究中得出的在固定 OLR 和变化的 OLR 下 PHB 含量取决于生物质浓度的结论，可以通过调整 SBR 中的生物质浓度，在处理富含 VFA 的废水时，除了选择富集 PHB 积累生物的策略外，还可以使污泥中的 PHB 含量尽可能高。
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