What can excessive flocculation lead to in a treatment process?

• A. Increased sedimentation
• B. Increased turbidity
• C. Floc breakthrough
• D. Under-sedimentation

Answer: (C)

Excessive flocculation can lead to floc breakthrough, which occurs when the flocs formed during the process become too large or dense and fail to settle properly during sedimentation. This situation can cause the floc to remain suspended in the water as it moves through the treatment process, thereby allowing turbidity and other impurities to pass through without adequate removal. When floc breakthrough happens, it can result in a compromised treatment plant performance, as the clarity and quality of the treated water are adversely affected.

In contrast, increased sedimentation refers to the enhanced settling of solids, which is generally a desired outcome in the flocculation process. Excessive flocculation is likely to disrupt this positive performance. Increased turbidity would normally be a result of poor flocculation rather than excessive flocculation, leading to more impurities being present in the treated water. Under-sedimentation would imply that not enough solids are settling, which typically ties back to inadequate flocculation rather than excessive flocculation. Thus, floc breakthrough is the most direct consequence of excessive flocculation in a treatment process.