In China, many urban drainage systems constructed in the 1980s and 1990s still rely heavily on combined sewer networks. During heavy rainfall, large volumes of stormwater enter the sewage pipes, subjecting wastewater treatment plants (WWTPs) to hydraulic shocks several times their design flow. For medium-sized plants with daily capacities of 20,000–60,000 m³, operational risks increase sharply:

• Influent flow:Peaks can reach 3–5 times the design flow, significantly shortening hydraulic retention time (HRT).
• Influent quality:SS peaks often exceed 500 mg/L, with COD and TP fluctuating dramatically.
• Biological system:Stormwater dilution reduces activated sludge concentration abruptly, increasing the risk of sludge bulking.
• Effluent risk:Delayed response may result in effluent violations, exposing the plant to environmental regulation and penalties.

To address these challenges, Hongtai Huarui has, through years of engineering practice, developed a mature, efficient, and intelligent “Rapid Combined Sewer Overflow (CSO) Treatment Solution”, successfully validated in multiple southern Chinese cities and Yangtze River basin projects.

I. Process Route: Focused on Rapid Peak Load Reduction

The solution follows the design principles of “front-end interception, high-efficiency sedimentation, high-speed filtration, and intelligent coordination”, adding an emergency treatment unit after the influent pump station to maximize protection of the downstream biological system.

1.1 High-Efficiency Sedimentation Unit — Magnetic Coagulation / Inclined Plate Sedimentation

Technical principle:
Magnetic seeds (Fe₃O₄ micropowder), PAC, and PAM are added to form high-density magnetic flocs, which settle rapidly under magnetic assistance. Combined with plate/pipe media, the unit achieves significantly higher volumetric sedimentation efficiency.

CSO Scenario Adaptation:
Equipped with an AI-based precise dosing system, magnetic seed and chemical dosing ratios are dynamically adjusted according to real-time data from flow meters, turbidity sensors, and SS sensors. While manual adjustment typically takes 20–40 minutes, AI response is completed in ≤90 seconds, ensuring stable flocculation even under rapidly fluctuating influent conditions.

1.2 High-Speed Filtration Unit — Denitrifying Deep-Bed Filters / Fiber Rotary Disk Filters

Effluent Quality Targets:

• SS ≤ 10 mg/L (meets Class A standards, can achieve quasi-Class IV for surface water).
• TP ≤ 0.3 mg/L (with pre-treatment chemical phosphorus removal).
• TN: Deep-bed filters can reduce TN by an additional 3–5 mg/L.

Operational Features:

• Fiber rotary disk filters are compact, ideal for upgrading old WWTPs without constructing large new structures.
• Backwash is automatically triggered by differential pressure sensors, requiring no manual intervention during CSO peaks.
• Deep-bed filters contain bioactive media; using available carbon sources, they perform simultaneous filtration and deep denitrification.

II. Hongtai Huarui FyhoneOS: From “Emergency Response” to “Proactive Prevention”

Fyhone AI is specifically designed for CSO scenarios, enabling full-process intelligent coordination. Key functional modules are as follows:

Traditional Mode vs. AI Mode:
Traditional operations rely on manual inspection and experience-based adjustments, leading to slow and delayed responses. Fyhone AI provides millisecond-level sensing, second-level decision-making, and minute-level execution, minimizing risk during CSO events.

III. Expected Benefits

• • Effluent Safety:Significant reduction in effluent exceedance during CSO events.
  • Chemical Costs:AI precision dosing reduces chemical consumption compared to manual control.
  • Energy Optimization:Intelligent aeration control lowers overall energy consumption.
  • Labor Requirements:No additional personnel required during CSO events, reducing operational staffing.
  • ROI:Energy and chemical savings typically allow AI system investment to be recovered within 18–24 months.

  IV. Typical Applications

  • Upgrading existing WWTPs in old urban districts with combined sewer networks.
  • Designing new WWTP pretreatment units to withstand 3–5× rainfall peak flows.
  • CSO emergency protection for WWTPs in southern rainy cities, the Yangtze River basin, and the Pearl River Delta.
  • Projects requiring high-standard effluent quality (quasi-Class IV for surface water).

   

  V. Why Choose Hongtai Huarui?

  

• • Mature Technology:Magnetic coagulation + high-speed filtration + AI control.
  • Flexible Retrofit:No large-scale construction required; can utilize space behind existing influent pump stations.
  • Intelligent Closed-Loop:Fully automatic coordination from warning, dosing, biological protection, to effluent guarding.
  • Rapid Payback:Significantly reduces chemical, energy, and labor costs, providing quantifiable economic benefits.

  Make every heavy rainfall no longer a “major test” for your WWTP.
  Hongtai Huarui — Delivering smarter, more reliable solutions for combined sewer overflow management.