State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
Water Res. 2021 Aug 1;201:117302. doi: 10.1016/j.watres.2021.117302. Epub 2021 May 28.
The first-order model is the most widely utilized model for chlorine decay due to its having only one parameter and an analytical solution. While variable reaction coefficient type models have higher accuracy and wider application range, their widespread uses are hindered by their complexity and the non-existence of an analytical solution. The objective of this study was to develop a variable parabolic reaction coefficient model to simulate and predict chlorine decay in bulk water. The decreasing reactivity of the reacting agents is included in a variable coefficient, which decreases with increasing consumption of the chlorine-reactive species concentration. The model includes minimal parameters that must be calculated, and an analytical solution was derived. Experimental data, including chlorination with different initial chlorine concentrations or temperatures, rechlorination, and water mixing, were utilized to evaluate the accuracy of the variable parabolic reaction coefficient model under different conditions. The relationship between the parameters and temperature was established utilizing the Arrhenius equation. On the basis of assumptions that the chlorine consumed by reactions with the pipe wall does not decrease the variable rate coefficient, this study subtracted the instantaneous aggregate chlorine wall consumption from the total chlorine consumption, so that the parameter values in the VPRC model (derived from laboratory decay tests) can be used in the system model. For output water at the entrance of the WDN with unknown initial chlorine concentration and unknown decay duration from disinfection to entry into the water distribution network, an effective method to determine the model parameter is proposed.
一阶模型是最广泛应用于氯衰减的模型，因为它只有一个参数和一个解析解。虽然变反应系数模型具有更高的准确性和更广泛的应用范围，但由于其复杂性和不存在解析解，它们的广泛应用受到阻碍。本研究的目的是开发一种变抛物线反应系数模型来模拟和预测大体积水中的氯衰减。反应试剂的反应性降低包含在一个随氯反应性物质浓度消耗而降低的变系数中。该模型包含了必须计算的最少参数，并推导出了一个解析解。利用不同初始氯浓度或温度下的氯化、再氯化和水混合的实验数据，评估了变抛物线反应系数模型在不同条件下的准确性。利用阿累尼乌斯方程建立了参数与温度之间的关系。基于假设与管壁反应消耗的氯不会降低变率系数，本研究从总氯消耗中减去瞬时总氯管壁消耗，以便在系统模型中使用从实验室衰减测试中得出的 VPRC 模型中的参数值。对于从进入供水管网到进入供水管网的未知初始氯浓度和未知衰减时间的入口处的出水，提出了一种确定模型参数的有效方法。
