Which of the following is not one of the commonly used methods of applying disinfectant?

The stream method is not recognized as a commonly used method of applying disinfectant in water treatment processes. Typically, techniques like chlorination, which involves adding chlorine to disinfect water, and the injection method, where disinfectants are pumped directly into the water system, are widely utilized. The tablet method also finds application in the water treatment process, where solid disinfectant tablets are used to gradually release chlorine as they dissolve in water.

In contrast, the term "stream method" is less specific and does not represent an established practice in the context of water disinfection compared to the other methods mentioned. This distinction is crucial in understanding the various approaches used in ensuring water quality and safety.