**Part 3: Troubleshooting Biological Processes in Wastewater Treatment Systems** 🔧### 1. Evaluate System Design and Operation 🏗️- **Veri...
Published on by Hossein Ataei Far, Deputy Manager of the Research, Technology Development, and Industry Relations Center at NWWEC
### 1. Evaluate System Design and Operation 🏗️
- **Verify Design Specifications**:
- **Action**: Review design documents and operational data to ensure the system operates within its design parameters and capacities.
- **Inspect Equipment**:
- **Action**: Ensure pumps, blowers, and other critical components are maintained regularly.
### 2. Monitor and Adjust 📈
- **Conduct Regular Monitoring**:
- **Action**: Measure key parameters (DO, pH, temperature) and analyze influent/effluent quality. Implement a routine monitoring schedule to track trends and identify potential issues.
- **Adjust Operations**:
- **Action**: Make necessary adjustments based on monitoring results to address identified issues and optimize system performance.
### 3. Key Components of Control ⚙️
- **Aeration Rate Adjustment** 🌬️
- **Objective**: Maintain proper dissolved oxygen (DO) levels in the aeration basin.
- **Methods**:
- Adjust airflow rates in diffused air systems based on the DO profile.
- Balance the number and placement of aerators in mechanically aerated systems.
- Consider BOD levels when adjusting aeration.
- **Reference**: Tchobanoglous et al. (2023), *Wastewater Engineering: Treatment and Reuse*.
- **Sludge Wasting Control** 🗑️
- **Objective**: Regulate sludge levels and quality.
- **Factors Affected**:
- Bacterial growth rate, oxygen consumption, settleability, and nutrient requirements.
- **Methods**:
- Adjust wasting rates to manage sludge age and food-to-microorganism ratio.
- Monitor indicators like sludge age, foam, and mixed-liquor concentration.
- **Reference**: Metcalf & Eddy (2020), *Wastewater Engineering: Treatment and Resource Recovery*.
- **Return Sludge Flow Control** 🔄
- **Objective**: Maintain appropriate microorganism concentration in the aeration basin.
- **Methods**:
- Regularly adjust return-sludge flow rate to avoid overloading or underloading.
- Monitor effects on settled sludge depth and mixed liquor concentration.
- **Reference**: Grady et al. (2022), *Biological Wastewater Treatment*.
**Control sludge wasting**:
It is also important to control sludge waste in the activated sludge process. Wasted sludge affects the following:
-Bacteria growth rate
-Oxygen consumption
-Mixed liquor settle-ability
-Occurrence of foaming/frothing
-The possibility of nitrifying
-Nutrient quantities needed
-Final effluent quality
- **Mass Balances** ⚖️
**Objective**: Ensure a balanced solids ratio entering and leaving the treatment unit.
- **Methods**:
- Evaluate mass balance by examining solids levels in the secondary clarifier and the amount leaving the system.
- **Reference**: Tchobanoglous et al. (2023), *Wastewater Engineering: Treatment and Reuse*.
Fig. 1-A biological floc composed of bacteria and protozoa (Processing Website).