Tennessee Wastewater Operator Practice Exam

What condition occurs when MLSS fails to flocculate effectively, leading to a turbid supernatant?

1. Dispersed growth

2. Settled growth

3. Flocculated growth

4. Active growth

The correct answer is: Dispersed growth

When Mixed Liquor Suspended Solids (MLSS) fails to flocculate effectively, it results in a condition known as dispersed growth. This condition arises when the microorganisms in the wastewater treatment process remain in a suspended or dispersed state rather than clumping together to form larger aggregates or flocs. In dispersed growth, the microorganisms do not settle well, which causes a turbid supernatant. Turbidity indicates that solids are still present in the liquid phase instead of forming a clear effluent. This can be problematic for wastewater treatment systems because it often results in poor clarification and can affect the overall efficiency of the treatment process. The inability of the biomass to flocculate is often a sign of imbalanced environmental conditions, such as nutrient deficiencies or improper pH levels. The other conditions mentioned, such as settled growth or active growth, refer to different scenarios within wastewater treatment processes. Settled growth indicates a situation where flocs have formed and settled successfully, leading to clear supernatant. Active growth typically describes a state where microorganisms are proliferating well, but it does not specifically address the issue of effective flocculation. Flocculated growth would imply that the MLSS is behaving correctly by forming flocs, which directly contrasts with