ISSN 1000-3665 CN 11-2202/P

    Al(III)和细菌引起的含水层化学-生物复合堵塞机理研究

    Mechanism of chemical-biological composite clogging of aquifer caused by Al(III) and bacteria

    • 摘要: 在采用人工回灌方法建设地下水库储存地下水的过程中,回灌水中三价铝(Al(Ⅲ))和细菌共同作用下引发的化学-生物复合堵塞问题突出且复杂,然而目前对其研究较少。本研究通过渗流试验模拟人工回灌过程,探究了细菌与0.05,0.20,0.60 mg/L Al(Ⅲ)共存条件下含水层的复合堵塞机制。研究结果表明,回灌水中Al(Ⅲ)可以改变石英砂的表面形态,促使含铝化合物生成化学沉淀。Si-O-Al键的生成证明Al(Ⅲ)的加入可以引起含水层化学堵塞。回灌水中不同浓度Al(Ⅲ)对堵塞的影响机制不同。0.05,0.20 mg/L较低浓度Al(Ⅲ)对细菌活性有抑制作用,减少细菌团聚,整体上降低了对生物堵塞贡献大的菌属占比,缓解了生物堵塞。0.60 mg/L高浓度Al(Ⅲ)会刺激细菌产生胞外聚合物,将大部分分散的细菌桥联,加剧生物堵塞。石英砂表面含铝化合物片状沉积物与细菌形态明显,可见含水层发生了化学-生物复合堵塞。本研究通过深入探讨Al(Ⅲ)和细菌与堵塞效应之间的关系,可以为优化回灌过程的设计和管理提供理论基础,进而保障地下水可持续利用。

       

      Abstract: This study investigated the chemical-biological clogging problem caused by the combined effect of aluminum trivalent (Al(Ⅲ)) and bacteria during artificial recharge processes. Laboratory-scale percolation experiments were conducted to explore the composite clogging mechanism of aquifers under the coexistence of bacteria and Al(Ⅲ) at the concentration of 0.05, 0.20, 0.60 mg/L. The results indicate that Al(III) in the recharge water could modify the surface morphology of quartz sand and promote the chemical precipitation of aluminum-containing compounds. The formation of Si-O-Al bonds proves that the addition of Al(III) can cause chemical clogging of the aquifer. Different concentrations of Al(III) in the recharge water have different effects on clogging. Low Al(III) concentrations of 0.05 and 0.20 mg/L alleviate bioclogging by inhibiting effect on bacterial activity, reducing bacterial aggregation, and overall decreasing the proportion of bacterial genera that contribute significantly to bioclogging. In contrast, high Al(III) concentrations of 0.60 mg/L can stimulate bacteria to produce extracellular polymers (EPS), which bridge most dispersed bacteria and aggravate bioclogging. Flake deposits of aluminum-containing compounds and bacterial morphology were observed on the quartz sand surface, further proving the role of Al(III) on chemical-biological complex clogging during the recharge processes. This study provides a theoretical basis for optimizing the design and management of the recharge process by improving our understanding of the relationship between Al(III) , bacteria, and clogging effects, thus ensuring the sustainable utilization of groundwater.

       

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