Several factors play a role in chlorine consumption in drinking water networks such as microbial contamination and dissolved organic matter (DOM). This study investigated the simultaneous impacts of seasonal variations on chlorine consumption and DOM composition for a year-long period in three different full-scale water distribution networks in a southern city of China. Efforts were made to determine the association between different fluorescence moieties in DOM of finished water and chlorine consumption through excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC). The chlorine consumption was also found to be directly related to N-Nitrosodimethylamine (NDMA) and NDMA-formation potential (NDMA-FP), presenting consequence of excess residual chlorine. The wet season with high rainfall showed elevated consumption of chlorine on the opposite of dry season. During wet season, humic-like component in finished water was dominant than protein-like features and its abundance decreased in dry season. Results proved that chlorine consumption was season dependent and highly influenced by DOM composition in the finished water. Unlike the bulk quality parameters and protein-like component, fluorescence moieties related to humic substances acted as a surrogate for the chlorine consumption. Based on humic-like component, a single excitation based fluorescence peak, I_245/410 or I_335/410, was also extracted from EEMs of finished water samples and validated on different water distribution networks. These two single peaks well-explained the trends of residual chlorine and have the potential for on-line monitoring and portable purposes. This field-based study demonstrated application of fluorescence spectroscopy in designing chlorine dose to obtain optimal residual chlorine at consumer’s tap.

饮用水网络中的氯消耗量中有几个因素，例如微生物污染和溶解性有机物（DOM）。这项研究调查了南方城市三个不同的全尺寸配水网络中一年中季节性变化对氯消耗和DOM组成的同时影响。通过激发-发射矩阵结合并行因子分析（EEM-PARAFAC），努力确定成品水的DOM中的不同荧光部分与氯消耗之间的关联。还发现氯的消耗量与氮直接相关-亚硝基二甲胺（NDMA）和NDMA形成势（NDMA-FP），带来过量残留氯的后果。与雨季相反，雨水多的雨季表明氯的消耗量增加。在雨季，成品水中的腐殖质样成分比蛋白质样特征占主导地位，而在旱季，其丰度下降。结果证明，氯的消耗量与季节有关，并且受成品水中DOM组成的影响很大。与总体质量参数和类蛋白成分不同，与腐殖质相关的荧光部分充当了氯消耗量的替代物。基于类腐殖质成分，基于单个激发的荧光峰I _245/410或I _335/410还从成品水样品的EEM中提取，并在不同的配水网络上进行了验证。这两个单峰很好地解释了残留氯的趋势，并具有在线监测和便携式用途的潜力。这项基于现场的研究证明了荧光光谱在设计氯剂量中的应用，以在消费者的水龙头上获得最佳的残留氯。