Part 8: **Addressing Excessive Energy Use in Wastewater Treatment: Innovations in Aeration Systems and Control Techniques to Reach Sustainabilit...
Published on by Hossein Ataei Far, Deputy Manager of the Research, Technology Development, and Industry Relations Center at NWWEC
Power consumption is crucial for the efficiency and sustainability of full-scale wastewater treatment plants (WWTPs). Here are some key insights from recent studies:
### Overview of Aeration in Wastewater Treatment
- **Energy Consumption Range:** The energy required for treating wastewater in WWTPs generally falls between **0.26 to 1.69 kWh per cubic meter**. This range varies based on technology, plant size, and operational practices. ⚡
- **Electrical Energy:** A major portion of energy use is tied to electrical needs, especially for pumping and aeration. Electrical energy alone can account for up to **52%** of total energy consumption, with aeration processes often consuming up to **79%** of this electrical energy. 💡
- **Manual Energy:** Manual tasks, such as chemical preparation and sludge management, contribute about **32%** of the total energy consumption. This percentage can vary based on the plant's design and automation level. 🛠️
Aeration is vital for supplying oxygen to microorganisms that break down organic matter in wastewater. However, it is one of the most energy-intensive processes, consuming between **50% and 90%** of a plant’s electricity and contributing **15% to 49%** of its operational costs. 🌬️
### Aeration Systems and Optimization
1. **Aeration Systems:**
- **Surface Aeration:** Once common, but now less favored due to high energy costs. 🌊
- **Diffused Aeration:** More widely used, employing blowers and fine-bubble diffusers to improve oxygen transfer efficiency. 💨
2. **Oxygen Transfer Efficiency (OTE):**
- **Factors Influencing OTE:** Includes wastewater composition, Standard Oxygen Transfer Efficiency (SOTE), diffuser depth, and temperature. 🌡️
- **Importance of Accurate Evaluation:** Crucial for optimizing aeration systems. 📈
3. **Optimization and Control:*
- **"Smart Control" Systems:* Implement SCADA systems to optimize aeration based on real-time data. 📊
- **Maintenance:* Regular maintenance of diffusers and advanced control strategies are key to maintaining efficiency. 🔧
**Note:* While aeration is essential, it is also costly. Advanced technologies and smart control systems can significantly cut costs. Proper design, maintenance, and operation are vital for effective and efficient wastewater treatment.
# References
1. Drewnowski, et al. (2019). *Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant*.
2. Sid, et al. (2017). *Cost Minimization in a Full-Scale Conventional Wastewater Treatment Plant: Associated Costs of Biological Energy Consumption Versus Sludge Production*.
3. Singh, et al. (2012). *Energy Pattern Analysis of a Wastewater Treatment Plant*.
Fig. 1: Power consumption for nitrifying activated sludge in Polish WWTPs.