Jianshi County Hongtuping Water Treatment Plant Expansion and Renovation Project
In Jianshi County, surrounded by the mountains of western Hubei, the Hongtuping Water Treatment Plant sits at an altitude of 1,100 meters, like a "natural water tower" suspended above the city. In 2023, after the completion of this 50-million-yuan renovation and expansion project, the county's water supply capacity jumped from 50,000 tons per day to 75,000 tons. With a disruptive technological innovation — three Krupp permanent magnet variable frequency oil-free screw blowers + a COD online linkage system — the plant achieved a milestone breakthrough in the history of gravity-flow water supply in mountainous areas. Operating entirely under a "zero-pumping" mode that relies on terrain drop for natural flow, the plant has stabilized effluent turbidity below 0.1 NTU, achieved a 100% pass rate for microbial indicators, and reduced filter backwash energy consumption by 45% year-on-year.
The "Energy Efficiency Paradox" of Mountain Water Plants: When Gravity Flow Meets the Battle for Water Quality
Hongtuping Water Plant has a unique topographical advantage. Water sourced from the Yesan River flows 22 kilometers entirely by gravity with a 380-meter drop to reach the plant. After purification, it relies on the remaining 120-meter drop to directly supply the urban area. This "zero-power water intake and supply" model should have made it an energy efficiency benchmark, but it faced severe challenges due to water quality upgrade requirements.
Due to the old process's lagging response to COD fluctuations in the raw water (reaching 15-25 mg/L during the rainy season), filter backwash relied on manual experience. To ensure backwash intensity, the Roots blowers operated at full load year-round, consuming over 800,000 kWh of electricity annually. At the same time, the backwash air volume regulation precision was only ±15%, resulting in 20% water waste from excessive backwashing, while insufficient backwashing led to filter media compaction.
Krupp System's Three Breakthroughs: Enabling Gravity Flow to Truly "Travel Light"
1. "Predictive breathing" under COD linkage
The three permanent magnet variable frequency blowers form a data closed loop with the inlet COD online monitor. When a COD fluctuation exceeding 2 mg/L is detected, the system automatically predicts changes in organic load. With ±1% air volume regulation precision (compared to ±10% for traditional equipment), the V-type filter backwash achieves "on-demand air supply," with the backwash cycle optimized from a fixed 12 hours to a dynamic 8-16 hours.
2. "Purification defense battle" with oil-free design
TüV Class 0 oil-free certification completely eliminates the risk of lubricating oil contamination. Compared to traditional oil-lubricated blowers, the oil content of the filter media is undetectable, the oil content in backwash water is 0 mg/L, and the filter media replacement cycle is extended to 6-8 years.
3. "Energy conservation" with permanent magnet variable frequency
The IE5 permanent magnet motor maintains efficiency above 94% across the 30%-100% load range. During morning and evening peak water usage periods, the blower automatically increases to 85% load. During nighttime low water usage periods, the blower intelligently reduces to 35% load. The comprehensive daily energy efficiency reaches 92.7%.
Data-Witnessed "Water Quality Leap"
After the renovation, the plant effluent turbidity dropped from 0.25-0.40 NTU to 0.05-0.10 NTU, dissolved oxygen control precision improved to ±0.3 mg/L, the microbial indicator pass rate reached 100%, and the fluctuation rate of key water quality parameters was reduced by 80%, achieving dual breakthroughs in energy conservation and water supply safety.
The practice at Hongtuping Water Plant reveals a deeper logic: the most extreme energy savings often lie within the most precise control. When the thousand-year-old wisdom of gravity flow meets Krupp's three technologies — ±1% precision air control, Class 0 oil-free assurance, and permanent magnet variable frequency efficiency enhancement — mountain water supply projects finally break through the limitation of "depending on nature" and enter a new era of "achieving high-quality water through technology."
