What is the major cause of short-circuiting in a sedimentation basin?

• A. Poor inlet baffling
• B. Excessive floc size
• C. Improper flow rate
• D. High water temperature

Answer: (A)

Short-circuiting in a sedimentation basin primarily occurs due to poor inlet baffling. Baffling is used in sedimentation basins to control water flow and ensure that the influent is evenly distributed throughout the basin, allowing ample time for sedimentation. When inlet baffling is insufficient or poorly designed, water can enter the basin too quickly or in a manner that creates turbulent flows, leading to areas where water bypasses the intended settling zone. This can result in less effective sedimentation and can lead to higher levels of suspended solids being discharged, ultimately affecting the overall efficiency of the water treatment process.

In contrast, excessive floc size, improper flow rate, and high water temperature can indeed affect sedimentation but do not directly cause short-circuiting. For example, excessive floc size might cause settling issues but would typically lead to increased sedimentation rather than a failure in the hydraulic design of the basin. Similarly, while improper flow rate can affect treatment efficiency, it would not specifically lead to the bypassing of water through the basin. High water temperature can influence the viscosity and density of the water, potentially affecting settling rates but not the hydraulic flow patterns directly responsible for short-circuiting.