Tang Liaofan, Gao Mingming, Liang Shuang, Wang Shuguang, Wang Xinhua
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China; Weihai Research Institute of Industrial Technology of Shandong University, Weihai, 264209, China.
Water Res. 2024 Apr 1;253:121315. doi: 10.1016/j.watres.2024.121315. Epub 2024 Feb 14.
The microalgal-bacterial granular sludge (MBGS) based enhanced biological phosphorus removal (EBPR) (MBGS-EBPR) was recently proposed as a sustainable wastewater treatment process. Previous work showed the possibility of obtaining an MBGS-EBPR process starting from mature MBGS and phosphate-accumulating organisms (PAOs) enriched aerobic granular sludge (AGS) and validated the effectiveness of removing carbon/nitrogen/phosphorus with mechanical aeration. The present work evaluated whether the same could be achieved starting from conventional activated sludge and operating under aeration-free conditions in an alternating dark/light photo-sequencing batch reactor (PSBR). We successfully cultivated filamentous MBGS with a high settling rate (34.5 m/h) and fast solid-liquid separation performance, which could be attributed to the proliferation of filamentous cyanobacteria and stimulation of extracellular polymeric substances (EPS) production. The process achieved near-complete steady-state removal of carbon (97.2 ± 1.9 %), nitrogen (93.9 ± 0.7 %), and phosphorus (97.7 ± 1.7 %). Moreover, improved phosphorus release/uptake driven by photosynthetic oxygenation under dark/light cycles suggests the enrichment of PAOs and the establishment of MBGS-EBPR. Batch tests showed similar phosphorus release rates in the dark but significantly lower phosphorus uptake rates in the presence of light when the filamentous granules were disrupted. This indicates that the filamentous structure of MBGS has minor limitations on substrate mass transfer while exerting protective effects on PAOs, thus playing an important role in sustaining the function of aeration-free EBPR. Microbial assays further indicated that the enrichment of filamentous cyanobacteria (Synechocystis, Leptoolybya, and Nodosilinea), putative PAOs and EPS producers (Hydrogenophaga, Thauera, Flavobacterium, and Bdellovibrio) promoted the development of filamentous MBGS and enabled the high-efficient pollutant removal. This work provides a feasible and cost-effective strategy for the startup and operation of this innovative process.
基于微藻-细菌颗粒污泥（MBGS）的强化生物除磷（EBPR）（MBGS-EBPR）工艺最近被提出作为一种可持续的废水处理工艺。先前的研究表明，从成熟的MBGS和富集了聚磷菌（PAO）的好氧颗粒污泥（AGS）出发，有可能获得MBGS-EBPR工艺，并验证了机械曝气去除碳/氮/磷的有效性。本研究评估了从传统活性污泥出发，在交替黑暗/光照的光序批式反应器（PSBR）中无曝气条件下运行是否能达到同样的效果。我们成功培养出了沉降速率高（34.5 m/h）且固液分离性能快速的丝状MBGS，这可归因于丝状蓝细菌的增殖和细胞外聚合物（EPS）产生的刺激。该工艺实现了碳（97.2±1.9%）、氮（93.9±0.7%）和磷（97.7±1.7%）的近乎完全稳态去除。此外，黑暗/光照循环下光合氧化驱动的磷释放/吸收改善表明PAO的富集和MBGS-EBPR的建立。批次试验表明，丝状颗粒被破坏时，黑暗中的磷释放速率相似，但光照下的磷吸收速率显著降低。这表明MBGS的丝状结构对底物传质的限制较小，同时对PAO发挥保护作用，从而在维持无曝气EBPR功能方面发挥重要作用。微生物分析进一步表明，丝状蓝细菌（集胞藻属、细鞘丝藻属和结节丝藻属）、假定的PAO和EPS产生菌（嗜氢菌属、陶厄氏菌属、黄杆菌属和蛭弧菌属）的富集促进了丝状MBGS的形成，并实现了高效污染物去除。这项工作为这种创新工艺的启动和运行提供了一种可行且具有成本效益的策略。
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