Three Gorges Water Yichang City Xingshan County Shenduhe Sewage Treatment Plant
The Shenduhe Sewage Treatment Plant construction project is a sub-item of the Yangtze River Protection Project in Xingshan County, undertaken by the Three Gorges Base Development Company. The project commenced in May 2019, covering an area of 25 acres with a total investment of 210 million yuan. It includes the construction of 9.5 kilometers of main sewage collection pipelines and has a designed treatment capacity of 20,000 tons per day. The process adopts "improved AAO + advanced treatment," and the effluent quality meets the Class A discharge standard. In July 2020, the project procured three Krupp oil-free screw blowers, which passed commissioning and began operation in December of the same year, with satisfactory performance. The project has enabled "full collection, full treatment, and full compliance" of domestic sewage from Xingshan county seat and three surrounding administrative villages, effectively improving the water environment quality of the Xiangxi River Basin and ensuring clean water flows into the Yangtze River.
Process Core: Key Bottlenecks of the Aeration System
The plant adopts an "improved AAO + advanced treatment" process, the core of which lies in the efficient degradation of pollutants by microorganisms in the biological reaction tank. Among them, the nitrification process in the aerobic zone requires extremely high precision and stability in controlling dissolved oxygen (DO). Nitrifying bacteria are extremely sensitive to DO. When the concentration falls below 1.5-2.0 mg/L, their activity drops significantly, leading to a sharp decline in ammonia nitrogen removal efficiency. Conversely, excessively high DO wastes energy and may破坏絮体结构 (disrupt floc structure). In mountainous areas, influent water quality and flow fluctuate significantly (e.g., during rainy seasons), requiring blowers to respond quickly and smoothly to load changes, maintain constant DO, and avoid impacts that could affect the nitrification/denitrification balance and the compliance of final effluent total nitrogen (TN) and total phosphorus (TP). Traditional aeration blowers often face bottlenecks in energy efficiency, control precision, and long-term stability when addressing these refined requirements, becoming potential risk points for stable compliance with the Class A standard.
Krupp Oil-Free Screw Blower's Breakthrough Approach
In July 2020, the Shenduhe Plant proactively introduced three Krupp oil-free screw blowers as the core power source for biochemical aeration, and they were successfully commissioned in December of the same year.
1. Precise aeration, efficient compliance
Krupp oil-free screw blowers are equipped with advanced variable frequency control systems. Based on the DO setpoint of the biological tank and real-time water quality parameters, they respond within milliseconds and provide stepless regulation of air volume and pressure. This ensures that under any influent load, the DO in the aerobic zone is precisely and stably maintained within the optimal range, creating the best living environment for nitrifying bacteria, significantly improving ammonia nitrogen removal efficiency and stability, and laying the foundation for TN control.
2. Excellent volumetric efficiency
The screw design itself has a wide high-efficiency operating range. Even under low-load conditions (such as at night), it maintains high efficiency, avoiding energy waste while ensuring stable dissolved oxygen supply.
3. Oil-free assurance, ecological safety
100% oil-free compressed air completely eliminates the risk of lubricating oil contaminating the mixed liquor. This not only protects the ecological health of activated sludge microorganisms, especially sensitive nitrifying bacteria, avoiding issues such as sludge toxicity, foam, or efficiency decline caused by oil contamination, but also eliminates the risk of secondary pollution of the final effluent quality (especially TP and COD) from oil mist entering the water body, making it an important safety foundation for stable compliance with the Class A standard.
4. Stable and reliable, safeguarding operation
Screw blowers have a robust structure, with core components that are wear-resistant, durable, and designed for a long service life. Their excellent reliability and low maintenance requirements provide solid assurance for the sewage plant to achieve uninterrupted stable operation 365 days a year and continuous compliance, overcoming the challenges that may exist in mountainous areas regarding operation and maintenance conditions.
Operational Results: A Clear Testament to Yangtze River Protection
Since commissioning at the end of 2020, the three Krupp oil-free screw blowers have been operating continuously with high efficiency and stability. With the strong support of precise aeration, the biochemical system at Shenduhe Plant operates efficiently and stably, with all effluent indicators consistently and stably exceeding the national Class A discharge standard, effectively reducing the total amount of pollutants discharged into the Yangtze River. Key indicators such as ammonia nitrogen and total nitrogen have performed particularly well in measured data. Over the three-year operating cycle, the equipment has demonstrated excellent reliability and low failure rates, ensuring continuous and stable operation of the plant.
Faced with high standards for effluent quality and complex water quality characteristics, the key to success lies in forward-looking mastery of core process links and precise selection of key equipment. With its precise DO control capability, 100% oil-free safety assurance, and excellent operational reliability, the Krupp oil-free screw blower provides core power support for the efficient and stable operation of the improved AAO process and continuous compliance with the Class A discharge standard, serving as a solid "air shield" protecting the water environment of the upper Yangtze River.
