Department of Civil and Environmental Engineering, Western University, 1151 Richmond Street, London N6A 5B9, ON, Canada.
Department of Civil and Environmental Engineering, Western University, 1151 Richmond Street, London N6A 5B9, ON, Canada; Bishop Water Inc., 203-16 Edward Street South, Arnprior K7S 3W4, ON, Canada.
Sci Total Environ. 2024 Dec 15;956:177337. doi: 10.1016/j.scitotenv.2024.177337. Epub 2024 Nov 9.
This research introduces a novel approach to achieve simultaneous nitrification-denitrification (SND) under dynamic load conditions using a cost-effective rope-type biofilm technology. The approach represents a significant advancement in wastewater treatment, particularly beneficial for remote and decentralized communities. The biofilm-based SND process was developed using a pilot-scale flow-through reactor by implementing upstream carbon management with constant-timer-based aeration control versus dynamic-sensor-based aeration control strategies. The findings indicate that adding an upstream anaerobic pretreatment process to handle excess carbon plays a substantial role in achieving a sustainable SND process under a dynamic load environment using simple aeration on-off control. The most optimal nitrification performance of 0.32 g NH-N/m/d (89 % removal) was achieved under a 1-hour ON/30-minute OFF aeration. The process sustained an average bulk liquid DO of 5.16 mg/L and 3.80 mg/L during the aeration ON and OFF periods, respectively, facilitating a 0.13 g N/m/d (41 %) total inorganic nitrogen (TIN) removal, notably, implementing advanced aeration strategies driven by DO, NH, and NO sensors enhanced TIN removal efficiency to 72 %. The nitrification performance remained comparable (89 % removal), resulting in 3 and 10 mg N/L effluent ammonia and TIN concentration, respectively. Additionally, utilizing two multivariate approaches accounting for 82 % and 64 % of the variance, this study discerned patterns in monitored variables and performance. Additionally, the analysis underscored the difference of bulk liquid DO levels in the biofilm versus suspended systems inhibiting the SND process. Distinct bacterial communities were established in biofilms under aerobic, anaerobic, and SND conditions, with the SND reactor showing a hierarchy of functional group and enzymes, enriched sequentially from heterotrophs to denitrifiers, nitrifiers, and anammox bacteria. These innovations underline the potential of tailored control strategies to enhance a passive biofilm-based SND process efficiency under dynamic conditions, providing scalable solutions for diverse target water quality demands in remote communities and decentralized systems.
本研究提出了一种在动态负荷条件下使用经济高效的绳状生物膜技术实现同步硝化-反硝化（SND）的新方法。该方法代表了废水处理领域的重大进展，特别是对偏远和分散社区具有重要意义。基于生物膜的 SND 工艺是通过在小试规模的流动反应器中采用上游碳管理，使用定时曝气控制与基于动态传感器的曝气控制策略相结合来开发的。研究结果表明，在动态负荷环境下，采用简单的曝气开关控制，在上游添加厌氧预处理过程来处理过量的碳，对于实现可持续的 SND 过程具有重要作用。在 1 小时 ON/30 分钟 OFF 曝气条件下，获得了最佳的硝化性能，NH-N/m/d 为 0.32（去除率为 89%）。该过程在曝气 ON 和 OFF 期间分别维持平均主体液体 DO 为 5.16 和 3.80mg/L，实现了 0.13g N/m/d（41%）的总无机氮（TIN）去除，值得注意的是，采用 DO、NH 和 NO 传感器驱动的高级曝气策略将 TIN 去除效率提高到 72%。硝化性能保持相当（去除率为 89%），导致出水氨氮和 TIN 浓度分别为 3 和 10mg/L。此外，利用两种多元分析方法，分别解释了 82%和 64%的变量方差，本研究识别了监测变量和性能的模式。此外，该分析强调了生物膜和悬浮系统中主体液体 DO 水平的差异，这抑制了 SND 过程。在有氧、厌氧和 SND 条件下，生物膜中建立了独特的细菌群落，SND 反应器依次显示了功能群和酶的层次结构，从异养菌到反硝化菌、硝化菌和厌氧氨氧化菌富集。这些创新突出了定制控制策略的潜力，可提高动态条件下被动生物膜 SND 工艺的效率，为偏远社区和分散系统中各种目标水质需求提供可扩展的解决方案。
