Tennessee Wastewater Operator Practice Exam

Processes with what characteristic experience slower diffuser bio fouling?

1. Low food-to-microbe ratios

2. High SRTs

3. Rapid growth rates

4. Low oxygen levels

The correct answer is: High SRTs

Processes characterized by high solids retention times (SRTs) experience slower diffuser biofouling primarily because longer SRTs allow for a greater overall acclimatization of microbial communities in the system. When the microbial population has a longer retention time, it can become more stable and more effectively adapted to the specific conditions of the wastewater treatment process. This adaptation leads to a well-balanced microbial community capable of efficiently utilizing available substrates, which in turn can contribute to the prevention of excessive biomass accumulation on diffusers. When the microbial growth conditions are stable, the rate of biofilm formation on diffusers is often lower, helping to maintain system efficiency and performance. In contrast, processes with low food-to-microbe ratios can lead to excessive starvations that might actually promote chaotic growth patterns. Rapid growth rates can cause an imbalance, leading to sloughing or excessive biomass that can contribute to fouling. Low oxygen levels can negatively impact microbial respiration efficiency and diversity, potentially leading to unhealthy biofilms. Thus, high SRTs play a crucial role in fostering a controlled environment that mitigates fouling issues.