Part 13: **Bioindicators: The Best Method for Early Detection of Operational Issues in WWTPs**Using protozoan analysis and the Sludge Biotic Ind...
Published on by Hossein Ataei Far, Deputy Manager of the Research, Technology Development, and Industry Relations Center at NWWEC
Using protozoan analysis and the Sludge Biotic Index (SBI) to monitor aeration and overloading in activated sludge systems provides valuable insights into the health and performance of wastewater treatment plants (WWTPs).
#### β **1. Presence of *Vorticella* in Balanced Quantities**
- **Function**: Indicates a well-functioning system. *Vorticella*, a genus of sessile protozoa, thrives in well-aerated environments, reflecting sufficient oxygen and effective organic load handling. π
- **Benefits**: Contributes to clearer effluent and stable system operation. π§ͺ
- **Impact**: A balanced population aids in sludge formation and improves sedimentation and separation processes. π
- **Research**: Balanced *Vorticella* populations lead to better sludge settling and effluent quality (Xiao et al., 2021).
#### β οΈ **2. Excess of *Vorticella* or Certain Species**
- **Indicators**: Overabundance, especially of *Vorticella microstoma*, suggests system imbalance. βοΈ
- **Symptoms**: Often indicates insufficient oxygen levels or unstable conditions. π
- **Consequences**: Can lead to inefficiencies in sludge settling and decreased water quality. πͺοΈ
- **Monitoring**: Helps detect early signs of poor aeration or overloading, allowing for timely adjustments (Zhang et al., 2023). β³
### π **Study and Findings**
**π Liliana AraΓΊjo dos Santos et al. (2014) analyzed 35 WWTP samples from textile and domestic sewage, identifying 30 protozoan and small metazoan taxa. Key findings include:
- **Microfauna Correlations**: Significant correlations with total suspended solids (TSS) and dissolved oxygen (DO).
- **Sludge Biotic Index (SBI)**: Reflected community health but did not align with effluent quality metrics like COD or BOD5.
- **Protozoan Indicators**:
- *Epistylis rotans*: Indicates good water quality π
- *Arcella sp.*: Associated with good oxygenation and nitrification π¬οΈ
- *Vorticella microstoma*: Indicates insufficient oxygenation and high organic load π«
- *Aspidisca cicada*: Reflects adequate performance but occasionally toxic inputs β οΈ
**π Key Results**:
- No direct correlation between biological parameters and treatment efficiency. However, microfauna provided operational insights, with unexpected correlations with effluent TSS indicating a need for further research. ππ
**π‘ Conclusions**:
- SBI and protozoan taxa offer valuable insights into WWTP operation but are limited in predicting treatment efficiency directly. Future studies should explore soluble COD and BOD measurements and further investigate the role of microfauna in wastewater treatment systems. ππ¬
### **Updated References:**
- π Ren, Z., et. al. (2022).
- π VidakoviΔ, J., et. al. (2021).
- π Xiao, Y., et. al. (2021).
- π Zhang, Q., et. al. (2023).
- π Burian, A., et. al. (2022).
- π dos Santos, L. A.,et. al. (2014).
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https://www.biorxiv.org/content/10.1101/2021.06.01.446513v1.full