When referring to water quality, what is an indicator of over-treatment in flocculation?

In the context of water treatment and flocculation, the formation of very tiny flocs is indeed an indicator of over-treatment. When flocculation occurs, the aim is to aggregate smaller particles into larger floc particles that can easily settle out of the water during sedimentation. If the treatment process is excessive, it can lead to the formation of very small, ineffective flocs instead of the larger, dense aggregates that are desirable. Tiny flocs may indicate that the coagulant was added in excess or that the conditions for optimal floc formation were not met, which can result in poor removal of contaminants.

In contrast, the presence of large flocs is generally viewed as a positive outcome of flocculation, indicating that the treatment has successfully clumped smaller particles together. Rapid sedimentation may also suggest effective flocculation, as larger flocs tend to settle more quickly. Retention time pertains to the duration of water treatment and is a critical factor for allowing flocculation to occur, but it doesn't directly indicate over-treatment in itself. Thus, the formation of very tiny flocs is the clear sign of over-treatment in the flocculation process.