Which of the following will not cause short circuiting in a clarifier?

A flow line of the launder being low does not inherently cause short circuiting in a clarifier. Short circuiting typically occurs when the flow path through the clarifier is disrupted, leading to inefficient settling and treatment of the water. A low flow line may affect the hydraulic conditions and could potentially result in higher water levels in the clarifier; however, it does not directly create the same turbulent flow conditions that would lead to short circuiting.

On the other hand, a high flow rate can overwhelm the clarifier's ability to adequately treat the influent, leading to bypassing effects and short circuiting. Similarly, having an uneven sludge blanket can create areas where some flow paths are significantly shorter than others, leading to the flow not adequately interacting with the sludge as it should. Improper placement of the influent feed can also direct flow in a way that promotes turbulence and maximizes the likelihood of short circuiting. Thus, the flow line of the launder being low is the least likely to cause these issues.