Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611AX Delft, the Netherlands; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, the Netherlands.
Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611AX Delft, the Netherlands.
Sci Total Environ. 2021 Jun 1;771:144847. doi: 10.1016/j.scitotenv.2020.144847. Epub 2021 Jan 19.
Conventional diffused aeration systems (such as fine-bubble diffusers) exhibit a poor oxygen transfer in wastewater treatment plants (WWTPs), particularly when operating at sludge concentrations higher than 15 g L. The supersaturated dissolved oxygen (SDOX) system has been proposed as an alternative for supplying dissolved oxygen (DO) at high mixed liquor suspended solids (MLSS) concentrations. The advantages introduced by such technology include the possibility of operating WWTPs at much higher than usual MLSS concentrations, increasing the treatment capacity of WWTPs. Recent studies have demonstrated that the SDOX system has higher oxygen transfer rates (OTRs) and oxygen transfer efficiencies (OTEs) relative to fine-bubble diffusers. However, it is unknown if the high-pressure conditions introduced by SDOX may possibly impact the biological performance of WWTPs. In this study, the effects of SDOX technology on the biological performance of a membrane bioreactor (MBR) were evaluated. The MBR was operated at an MLSS concentration of approximately 15 g L in four phases as follows: (P1) with bubble diffusers, (P2) with an SDOX unit, (P3) with the bubble diffusers, and (P4) with the SDOX unit. The performance of the MBR was assessed by monitoring the sludge concentration, as well as changes in the particle size distribution (PSD), sludge activity, organic matter removal and nitrification performance, and changes in the microbial community within the MBR. The operational conditions exerted by the SDOX technology did not affect the concentration of active biomass during the study period. The biological performance of the MBR was not affected by the introduction of the SDOX technology. Finally, the microbial community was relatively stable although some variations at the family and genus level were evident during each of the study phases. Therefore, the SDOX system can be proposed as an alternative technology for DO supply in WWTPs increasing the overall treatment capacity.
传统的扩散曝气系统（如微孔曝气器）在污水处理厂（WWTP）中的氧气转移效率较差，特别是在污泥浓度高于 15 g/L 时。过饱和溶解氧（SDOX）系统已被提议作为在高混合液悬浮固体（MLSS）浓度下供应溶解氧（DO）的替代方法。该技术的优点包括 WWTP 可以在远高于通常 MLSS 浓度的条件下运行，从而提高 WWTP 的处理能力。最近的研究表明，与微孔曝气器相比，SDOX 系统具有更高的氧气转移速率（OTR）和氧气转移效率（OTE）。然而，目前尚不清楚 SDOX 引入的高压条件是否可能影响 WWTP 的生物性能。在这项研究中，评估了 SDOX 技术对膜生物反应器（MBR）生物性能的影响。MBR 在四个阶段以约 15 g/L 的 MLSS 浓度运行，具体如下：（P1）使用气泡曝气器，（P2）使用 SDOX 单元，（P3）使用气泡曝气器，和（P4）使用 SDOX 单元。通过监测污泥浓度、颗粒尺寸分布（PSD）变化、污泥活性、有机物去除和硝化性能以及 MBR 内微生物群落的变化来评估 MBR 的性能。在研究期间，SDOX 技术的操作条件并未影响活性生物量的浓度。MBR 的生物性能不受 SDOX 技术引入的影响。最后，尽管在每个研究阶段都存在一些变化，但微生物群落相对稳定。因此，SDOX 系统可以作为 WWTP 中 DO 供应的替代技术，提高整体处理能力。
