混合是指水供应商在处理厂上游、处理期间或处理后混合多个供水。本研究的重点是混合含有不同二级消毒剂的水。导致水供应商实践或考虑混合不同质量的水的情况包括:一个水供应商从另一个水供应商购买水，其中一个供应商修改消毒实践以响应不断变化的法规；紧急情况下使用与相邻系统的连接；而且，相邻系统连接在一起以管理增长。令人担忧的是，在分配有时含有游离余氯、有时含有组合余氯（氯胺）或有时含有氯化水和氯胺水的组合或混合物的水时，分配系统中的水质管理能力。 如果无法避免混合，可以实施操作策略和工程控制，以将混合对水质的影响降至最低。案例研究旨在证明这些影响的性质，并提出适当的控制措施。包括22个参考文献、图表。

Blending refers to water suppliers mixing multiple supplies either upstream of treatment works, during treatment, or after treatment. The focus of this study is blending waters containing different secondary disinfectants. Situations that give rise to water suppliers practising or considering blending water of different quality include: one water supplier purchases water from another, where one supplier modifies disinfection practices to respond to changing regulations; connections to adjacent systems are used in emergency situations; and, adjacent systems are joined together to manage growth. Of concern is the ability to manage water quality in the distribution system when distributing water that sometimes contains a free chlorine residual, sometimes a combined chlorine (chloramine) residual, or sometimes a combination or blend of chlorinated and chloraminated water. If blending cannot be avoided, operating strategies and engineering controls can be implemented to minimize the water quality impacts of blending. Case studies are presented to demonstrate the nature of these impacts and to suggest appropriate control measures. Includes 22 references, figures.