Dominance of flagellates in your mixed liquor indicate ____________?

The presence of a dominance of flagellates in the mixed liquor generally indicates conditions where organic loading is relatively high, along with a low food-to-microorganism (F:M) ratio. Flagellates are typically adapted to environments with abundant organic matter, which leads to their proliferation.

When the F:M ratio is high, there is more food available relative to the microorganisms present, which could favor bacteria that are more robust and better suited to processing this organic material, such as filamentous organisms. However, in conditions where the F:M ratio is low, flagellates thrive because they are efficient at consuming the available organic matter in lower concentrations, leading to their dominance in the mixed liquor.

Additionally, a low solids retention time (SRT) implies that there is a quick turnover of biomass in the system. This scenario can also favor the growth of flagellates, as they can reproduce rapidly under such conditions. If the SRT were high, more stable populations of other microorganisms would likely dominate the system instead.

In summary, the dominance of flagellates indicates a scenario with a high F:M ratio and a low SRT, making them well-suited to utilize the available food resources effectively.