Wu Yang, Zhou Dakai, Lu Yongze, Li Shuping, Zhu Guangcan, Wang Hongyang
School of Energy and Environment, Southeast University, Nanjing 210096, China.
School of Energy and Environment, Southeast University, Nanjing 210096, China; Key Laboratory of Water Pollution Control and Ecological Restoration of Xizang, National Ethnic Affairs Commission, Xizang Minzu University, Xianyang 712082, China; Key Laboratory of Water Safety and Aquatic Ecosystem Health of Xizang, Xizang Minzu University, Xianyang 712082, China.
Water Res. 2025 Jan 1;268(Pt B):122695. doi: 10.1016/j.watres.2024.122695. Epub 2024 Oct 23.
At high altitudes, the low air pressure, low atmospheric oxygen content, and cryogenic environment during the cold season greatly limit the treatment efficiency of wastewater treatment plants (WWTPs). A novel pilot-plant configuration of the multi-stage baffled AO wastewater treatment process was proposed and tested in Xizang. Different operational conditions involving at different influent loads and at low temperatures (10.0-11.0 °C) were tested. When the influent flowrate increased to 4 m∙d, the hydraulic retention time (HRT), internal and external reflux ratio, dissolved oxygen (DO), and aeration demands (gas to water ratio) all decreased to 34.2 h, 3.5/7, a stable 2.0-2.5 mg∙L, and 17.5, respectively. The effluent chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH-N), and total phosphorus (TP) all met the requirements of Class 1 Grade A of the China National Municipal Wastewater Discharge Standards (GB 18918-2002). The contribution of denitrifying phosphorus removal (DPR) to the removal of both nitrogen and phosphorus was over 50%. The alpha diversity and abundance of the top genera in the microbial community structure were both higher than the plateau WWTP. The reaction activity of the DPR process was significantly enhanced via the increased abundance of key functional genes within the metabolism pathway of ammonia-oxidizing bacteria (AOB) and nitrogen-oxidizing bacteria (NOB). The special multi-stage baffled structure featured a strategy of high sludge storage that improved the system tolerance for low temperatures and ensured favorable and stable performance for nitrogen and phosphorus removal at low temperatures. A short, periodic, and cyclically intermittent operation mode, with each cycle lasting only 20 min, effectively inhibited filamentous bacteria sludge bulking, resulting in a sludge volume index (SVI) that decreased to within 120 mL∙g during the first 15 days of system start-up. A long sludge retention time (SRT) with no sludge discharging over 169 days and reduced aeration demands contributed to lower operation costs. The investigation revealed that the system had a high capacity for storing sludge phosphorus, possessing a TP content within a range of 23.45-28.99 mg∙g. This study provides a feasible solution for efficiently and economically treating wastewater in high-altitude areas.
在高海拔地区，寒冷季节的低气压、低大气含氧量和低温环境极大地限制了污水处理厂（WWTPs）的处理效率。提出了一种新型的多级折流板AO污水处理工艺中试装置配置，并在西藏进行了测试。测试了不同进水负荷和低温（10.0 - 11.0°C）下的不同运行条件。当进水流量增加到4 m∙d时，水力停留时间（HRT）、内外回流比、溶解氧（DO）和曝气需求（气水比）分别降至34.2 h、3.5/7、稳定在2.0 - 2.5 mg∙L和17.5。出水化学需氧量（COD）、总氮（TN）、氨氮（NH - N）和总磷（TP）均满足《城镇污水处理厂污染物排放标准》（GB 18918 - 2002）一级A标准的要求。反硝化除磷（DPR）对氮和磷去除的贡献率均超过50%。微生物群落结构中优势属的α多样性和丰度均高于高原污水处理厂。通过氨氧化细菌（AOB）和亚硝酸盐氧化细菌（NOB）代谢途径中关键功能基因丰度的增加，显著提高了DPR过程的反应活性。特殊的多级折流板结构具有高污泥储存策略，提高了系统对低温的耐受性，并确保了低温下氮磷去除的良好稳定性能。一种短周期、周期性和循环间歇运行模式，每个周期仅持续20分钟，有效抑制了丝状菌污泥膨胀，在系统启动的前15天内污泥体积指数（SVI）降至120 mL∙g以内。169天不排泥的长污泥停留时间（SRT）和降低的曝气需求有助于降低运营成本。研究表明，该系统具有较高的污泥磷储存能力，TP含量在23.45 - 28.99 mg∙g范围内。本研究为高海拔地区高效经济地处理废水提供了一种可行的解决方案。
