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首页> 外文会议>International Conference on Groundwater Research, Jun 6-8, 2000, Copenhagen, Denmark >Kinetic model for oxygen transport in the presence of an oxygen bubble wall
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Kinetic model for oxygen transport in the presence of an oxygen bubble wall

机译：氧气气泡壁存在下氧气传输的动力学模型

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摘要

Oxygen phase transfer plays an essential role for successful application of enhanced aerobic biodegradation (e.g. biosparging, oxygen bubble walls) for dissolved organic contaminants in groundwater. The key parameter for the efficiency of this in situ technologies is the microscopic transfer coefficient α. Assuming that diffusion in the water phase is the rate limiting process, the stagnant film model yields α≈ 3.3*10~(-8) m/s (Schwarzenbach et al., 1993). Recent experimental and theoretical investigations (Donaldson et al., 1997) indicate that for column experiments with a water velocity u ≈ 4m/day the transfer coefficient is by 2 orders of magnitude larger (α≈ 10~(-6) m/s); hence the stagnant film model breaks down in this velocity range. In order to prove this important conclusion, we have calculated the breakthrough curve once again both in constant volume- and in constant pressure approach. Based on our calculations we reinterpret the experimental results of Donaldson et al. and obtain α≈ 10~(-8) m/s. The reason for this discrepancy is that Donaldson et al. used the wrong differential equation for the residual gas phase. Therefore our main conclusion is that the stagnant film model is still valid for higher velocities (up to 4m/day) and gives the right order of magnitude for α.
机译：氧气相转移对于成功应用增强的好氧生物降解作用（例如生物喷射，氧气气泡壁）起着至关重要的作用，以解决地下水中溶解的有机污染物的问题。这种原位技术效率的关键参数是微观传递系数α。假设在水相中的扩散是限速过程，那么停滞的膜模型将产生α≈3.3* 10〜（-8）m / s（Schwarzenbach等，1993）。最近的实验和理论研究（Donaldson等，1997）表明，对于水速u≈4m / day的柱实验，传递系数要大2个数量级（α≈10〜（-6）m / s）。 ;因此，停滞的胶卷模型在该速度范围内崩溃。为了证明这一重要结论，我们再次以恒定体积和恒定压力方法计算了穿透曲线。根据我们的计算，我们重新解释了唐纳森等人的实验结果。得到α≈10〜（-8）m / s这种差异的原因是唐纳森（Donaldson）等人。对残留气相使用了错误的微分方程。因此，我们的主要结论是，停滞的膜模型对于较高的速度（高达4m / day）仍然有效，并且给出了α的正确数量级。

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