Yu Siwei, Hao Tianqi, Peng Xiaoshuai, Xu Yifeng, Fang Linchuan, Peng Lai
Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen, 518000, Guangdong, China.
Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, 430070, China.
J Environ Manage. 2025 Sep;392:126741. doi: 10.1016/j.jenvman.2025.126741. Epub 2025 Jul 29.
Purple phototrophic bacteria (PPB) are promising candidates for sustainable wastewater treatment and resource recovery due to their versatile metabolism and valuable biomass. However, their suspended growth and poor settleability hinder effective biomass retention and recovery. In this study, a photo-sequencing batch reactor (PSBR) was operated long-term to cultivate PPB granules through multiple strategies, including upflow velocity regulation and sodium, calcium, and magnesium ion addition. Under optimized conditions, PPB granules with excellent settling performance (77.98 m/h) and a median particle size of 255.48 μm were successfully formed, while flocculent sludge was nearly eliminated. Increasing upflow velocity from 3.15 to 4.5 m/h improved particle size distribution (D90 increased from 533.19 to 896.88 μm). Sodium addition (5 g/L) enhanced granule adhesion by increasing extracellular polysaccharides (PS) content by 71.95 %, while calcium and magnesium (100 mg/L each) improved structural integrity by increasing extracellular protein (PN) content by 38.80 % and promoting uniformity. Microbial analysis revealed dynamic community succession, with Rhodobacter and Psychrobacter dominanting in the later stage, and extracellular polymeric substances (EPS)-associated genera such as Brevundimonas and Flavobacterium contributing to granule stability. The system achieved a COD removal efficiency of 84.41 %, with a removal rate of 0.75 kg COD/m/d under 2 d hydraulic retention time (HRT) and 0.9 kg COD/m/d organic loading rate (OLR), showing comparable performance to previously reported PPB-based systems. In addition, PPB granules accumulated high-value products including proteins (39.91 %) and pigments (5.34 %), supporting their potential for wastewater resource recovery. This study provides insights into optimizing PPB granule formation and highlights the feasibility of PPB-based granular systems for practical applications.
紫色光合细菌（PPB）由于其多样的代谢方式和有价值的生物质，是可持续废水处理和资源回收的理想候选者。然而，它们的悬浮生长和沉降性能差阻碍了有效的生物质保留和回收。在本研究中，通过光序批式反应器（PSBR）长期运行，采用多种策略培养PPB颗粒，包括调节上流速度以及添加钠、钙和镁离子。在优化条件下，成功形成了沉降性能优异（77.98 m/h）、中位粒径为255.48μm的PPB颗粒，同时絮凝污泥几乎被消除。将上流速度从3.15提高到4.5 m/h改善了粒径分布（D90从533.19增加到896.88μm）。添加钠（5 g/L）使细胞外多糖（PS）含量增加71.95%，从而增强了颗粒附着力，而钙和镁（各100 mg/L）使细胞外蛋白质（PN）含量增加38.80%并促进均匀性，从而改善了结构完整性。微生物分析揭示了动态群落演替，后期红杆菌属和嗜冷杆菌属占主导，而与细胞外聚合物（EPS）相关的属如短波单胞菌属和黄杆菌属有助于颗粒稳定性。该系统在2天的水力停留时间（HRT）和0.9 kg COD/m/d的有机负荷率（OLR）下，COD去除效率达到84.41%，去除速率为0.75 kg COD/m/d，表现出与先前报道的基于PPB的系统相当的性能。此外，PPB颗粒积累了包括蛋白质（39.91%）和色素（5.34%）在内的高价值产品，证明了其在废水资源回收方面的潜力。本研究为优化PPB颗粒形成提供了见解，并突出了基于PPB的颗粒系统在实际应用中的可行性。
