Part 1: Troubleshooting Biological Processes in Wastewater Treatment Systems** 🔧Troubleshooting biological processes in wastewater treatment ...
Published on by Hossein Ataei Far, Deputy Manager of the Research, Technology Development, and Industry Relations Center at NWWEC
Troubleshooting biological processes in wastewater treatment systems requires a systematic approach to identify and resolve issues that can impact treatment efficiency and effectiveness. Here’s a guide to the major steps and common issues:
### 1. **Identify Symptoms of Problems** 🔍
- **Increased Effluent BOD/COD** 📉: Indicates reduced biological activity or inefficient treatment.
- *Symptoms*: High levels of biochemical oxygen demand (BOD) or chemical oxygen demand (COD) in the treated effluent suggest that the system is not effectively breaking down organic matter.
- **Poor Settling Sludge** 🚱: Can lead to increased turbidity and poor effluent quality.
- *Symptoms*: Excessive sludge in the secondary clarifier or a high sludge volume index (SVI) can result in poor settling and elevated turbidity.
- **Foaming** 🧼: Often caused by excessive biological growth or the presence of surfactants.
- *Symptoms*: Persistent foam on the surface of aeration tanks or secondary clarifiers may indicate high surfactant levels or biological overgrowth.
- **Odors** 👃: Suggests anaerobic conditions or the buildup of certain compounds.
- *Symptoms*: Unpleasant smells, such as hydrogen sulfide or ammonia, indicate poor aeration or incomplete treatment.
### 2. **Check Process Parameters** 📊
- **Temperature** 🌡️: Ensure it is within the optimal range for microbial activity (typically 10-35°C).
- *Action*: Regularly verify temperature readings and maintain the system within the ideal range for microorganisms.
- **pH** 🌡️: Check pH levels; most processes work best between pH 6.5 and 8.5.
- *Action*: Regularly monitor and adjust pH to keep it within the optimal range for microbial activity and process stability.
- **Dissolved Oxygen (DO)** 💧: For aerobic processes, DO should be above 2 mg/L; lower levels may compromise microbial activity.
- *Action*: Adjust aeration rates to maintain adequate DO levels, ensuring that aerobic microorganisms have sufficient oxygen.
- **Sludge Age (SRT)** ⏳: Ensure it is within the recommended range for the specific process.
- *Action*: Monitor and adjust sludge age to maintain process stability and effectiveness, especially in activated sludge systems.
- **Hydraulic Retention Time (HRT)** 🕰️: Verify that it meets design specifications.
- *Action*: Ensure hydraulic retention time aligns with design specifications to allow sufficient contact time for treatment.
### References 📚
1. **Metcalf & Eddy, Inc. (2020)**. *Wastewater Engineering: Treatment and Resource Recovery*.
2. **Tchobanoglous, G., Stensel, H.D., Tsuchihashi, R., & Leverenz, H.L. (2023)**. *Wastewater Engineering: Treatment and Reuse*.
3. **Grady, C.P.L., Daigger, G.T., & Love, N.G. (2022)**. *Biological Wastewater Treatment*.