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| Abstract: |
| An accurate chlorine bulk decay model is needed to ensure that potable water meets the microbial and the chemical safeties at the treatment plant and throughout the distribution. Among the mathematical models available, the general second-order chlorine bulk decay model (GBDM) is the most fundamentally sound. Application of the GBDM, however, has been hindered by its numerous fictive parameters and lack of an analytical solution. This theoretical work removes the two obstacles. The GBDM is solved through transformation and integration. The analytical solution provides deep insights into the GBDM and facilitates the parameterization and sensitivity analysis. The background natural organic matter (NOM) is characterized with the probabilistic distribution of functional groups. It reveals that the mean of the function group distribution is correlated with the initial chlorine decay rate coefficient (κ0). A simple formula is developed to determine κ0 directly from the initial chlorine decay. The theoretical treatment reduces the fictive parameters to a minimum. For the common lognormal distribution, the GBDM needs only three parameters, well defined as initial chlorine demand X0, median rate coefficient km, and heterogeneity index σ. For more complicated scenarios, composite distributions are constructed through superposition of individual distributions. A highlighted example is to predict chlorine decay in blends of different waters. With the theoretical and mathematical advancement here, the GBDM can be applied effectively to any reactive background matter in any reaction systems. |
| Key words: chlorine residual potable water natural organic matter decay model |
| DOI：10.11916/j.issn.1005-9113.16116 |
| Clc Number:TU991 |
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| Descriptions in Chinese: |
| 饮用水余氯衰减的理论模型与分析 齐少英1，鲁金凤2,3 (1.美国伊利诺伊大学香槟分校 土木与环境工程系； 2.南开大学 环境科学与工程学院，天津 300071; 3.环境污染过程与基准教育部重点实验室(南开大学)，天津 300071） 创新点说明：本文的理论工作消除了两个当前研究领域的障碍：通过数学变换和积分求解了GBDM；通过解析解深入洞察GBDM，促进了参数化和灵敏度分析。 研究目的： 一个准确的氯衰减模型是必要的，以确保饮用水在水处理厂和整个管网供水过程中都符合微生物和化学安全性。在现有的数学模型中，综合二阶氯衰减模型（GBDM）从基础角度来看是不错的. 然而， GBDM的应用却由于其众多的虚拟参数和缺乏解析解而被阻碍。 研究方法： 通过数学变换和积分求解GBDM 结果： 通过解析解可以深入洞察GBDM，同时促进了参数化和灵敏度分析。天然有机物（NOM）本底的官能团分布可以用概率分布表征，它揭示了官能团的平均分布是与初始氯衰减速率常数（k0）成正相关的。开发了一个简单的直接计算该初始氯衰减速率常数的公式。理论处理将虚构参数减少到了最少状态。对常规对数正态分布而言，GBDM只需要三个参数，即初始需氯量x0，中值速率系数和不均匀指数σ。对于更复杂的情况，复合分配通过个体分布的叠加构造。一个突出的例子是在不同的水混合后预测氯衰减。 结论： 理论和数学模型的发展，使GBDM可以有效地应用于任何反应体系中的任何反应背景物质。 关键词：余氯；饮用水；天然有机物；衰减模型 |
