College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang 310058, China.
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang 310058, China.
Water Res. 2022 Jul 15;220:118595. doi: 10.1016/j.watres.2022.118595. Epub 2022 May 18.
The traditional methods of increasing the chlorine disinfectant dosage in the drinking water distribution system (DWDS) to control microorganisms and improve the safety of drinking water quality are subjected to several challenges. One noticeable problem is the unpleasant odor generated by chlorine and chloramines. However, the generally proposed chlorine dosage optimization model ignores the chloric odor distribution in the DWDS. This study proposes a comprehensive multi-parameter water quality model and aims to balance the trade-offs between: (i) minimize the flavor profile analysis (FPA) degree of the chloric odor produced by chlorine and chloramines in the DWDS, and (ii) minimize the economic investment (chlorine dosage and operation cost). EPANET and back propagation (BP) network integrated with the Borg algorithm were employed as innovative approaches to simulate the chlorine, chloramines, and chloric odor intensity in the DWDS. Moreover, the application of the multi-parameter model was demonstrated in a real-world DWDS case study. 0.5 mg-Cl/L (mg/L) chlorine at 8 secondary chlorination points was added to the DWDS as an optimized chlorine dosing scheme considering the olfactory and financial objective functions simultaneously. When switching to a superior water source, the FPA of the chloric odor in DWDS increased by a maximum of 1.4 at most if the initial chlorine dosage remained as before. To avoid the occurrence of chloric odor and also control the residual free chlorine (residual chlorine) at a suitable value, the initial and secondary chlorine dosages were optimized to 0.4 mg/L and 0.3 mg/L, respectively. Under this condition, the initial chlorine dosage was reduced by 50% compared to the original operation scheme in City J, China, the qualification rate of the residual chlorine reached 97.2%, basically consistent with that before water source switching, and the chloric odor intensity of the DWDS was controlled below FPA 3.4.
传统的增加饮用水分配系统（DWDS）中氯消毒剂剂量以控制微生物并提高饮用水水质安全性的方法面临着几个挑战。一个值得注意的问题是氯和氯胺产生的不愉快气味。然而，一般提出的氯剂量优化模型忽略了 DWDS 中的氯气味分布。本研究提出了一个全面的多参数水质模型，旨在平衡以下方面的权衡：（i）最小化 DWDS 中氯和氯胺产生的氯气味的风味剖面分析（FPA）程度，和（ii）最小化经济投资（氯剂量和运营成本）。EPANET 和与 Borg 算法集成的反向传播（BP）网络被用作模拟 DWDS 中氯、氯胺和氯气味强度的创新方法。此外，多参数模型的应用在实际 DWDS 案例研究中得到了验证。考虑到嗅觉和财务目标函数，在 8 个二级氯化点向 DWDS 中添加 0.5 mg-Cl/L（mg/L）的氯作为优化的氯投加方案。当切换到优质水源时，如果初始氯剂量保持不变，则 DWDS 中氯气味的 FPA 最多增加 1.4。为了避免氯气味的发生并将余氯控制在适当的值，优化了初始和二级氯剂量分别为 0.4 mg/L 和 0.3 mg/L。在这种情况下，与中国 J 市的原始运行方案相比，初始氯剂量减少了 50%，余氯合格率达到 97.2%，基本与水源切换前一致，DWDS 的氯气味强度控制在 FPA 3.4 以下。
