What is a principal problem associated with preliminary treatment screening in water treatment?

The principal problem associated with preliminary treatment screening in water treatment is clogging. When water enters the treatment facility, it often carries debris, such as leaves, sticks, and other large solids. The primary purpose of screening is to remove these larger particles to prevent damage to downstream processes and equipment. However, if the screening equipment becomes overwhelmed, or if there are not adequate methods in place for cleaning and maintaining the screens, clogging can occur. This buildup of debris can hinder flow rates, create operational challenges, and lead to potentially costly equipment failures if not properly managed.

Each of the other options relates to different aspects of water treatment processes but does not specifically capture the core issue of preliminary screening. Odor control is more about managing the chemical processes rather than directly tied to screening itself. Color removal typically involves more advanced treatment processes focused on removing dissolved organic compounds or pigments rather than the initial screening stage. Temperature fluctuations may impact treatment efficiency but are usually not a direct concern of the preliminary screening phase. Thus, clogging stands out as the most relevant problem associated with preliminary treatment.