I. Challenges of Municipal Wastewater Disinfection and the Need for Technological Innovation
1.1 Industry Pain Points in Large-Volume Wastewater Treatment
The core difficulty in upgrading municipal wastewater treatment plants lies in balancing the efficiency and cost of disinfection. Traditional chlorine disinfection faces three major bottlenecks:
· Chemical residue risk: Residual chlorine and its derivatives (such as trihalomethanes) threaten aquatic ecosystems and recycled water safety;
· Ineffectiveness of resistant microorganisms: Chlorine-resistant pathogens such as fecal coliform bacteria require extremely high doses (≥15 mg/L), resulting in significant costs;
· Poor adaptability to water volume fluctuations: For projects with a daily treatment capacity of over 200,000 tons, the peak-to-valley flow rate can vary by as much as five times (e.g., the Wang Xiaoying project, with a flow rate of 2,500–290,000 m³/d). Fixed dosing results in wasted energy.
1.2 Opportunities for Technological Upgrades in Ultraviolet Disinfection
Ultraviolet (UV) disinfection, with its advantages of zero chemical addition, broad-spectrum bactericidal activity, and instantaneous response, has become the preferred method for upgrading municipal wastewater. However, traditional horizontal module technology has limitations in high-volume water applications:
· Uneven light field coverage: Arranging lamps parallel to the water flow direction can easily create disinfection blind spots;
· Scaling leads to reduced efficiency: The scale deposition rate increases by 40% when the quartz sleeve is installed horizontally;
· High maintenance costs: A single module failure requires the entire unit to be hoisted, resulting in production downtime losses of up to 10,000 yuan per hour.
The Hefei Wangxiaoying Wastewater Treatment Plant (290,000 tons/day), one of the first benchmark projects in China to implement the Class A standard, has pioneered the introduction of the ONYX Vertical Modular UV Disinfection System (WTV Series), providing an innovative solution for the industry.
II. Core Breakthroughs of ONKY Vertical Module Technology (WTV Series)
2.1 Technical Principle: Three-Dimensional Light Field Optimization and Intelligent Control
Unlike traditional horizontal modules, WTV technology enhances disinfection efficiency through three key innovations:
1. Vertical Plum Blossom-Shaped Lamp Arrangement:
The lamps are perpendicular to the water flow, forming a full-section radiation network and eliminating short-circuit blind spots.
The plum blossom-shaped layout improves UV intensity distribution uniformity to 95% (compared to only 70% for traditional horizontal modules).
2. Gravity-Driven Self-Cleaning and Anti-Scaling:
Gravity accelerates the shedding of dirt from the vertical quartz tube, reducing the frequency of mechanical cleaning by 50%.
Measured tube transmittance degradation is ≤5% per year (compared to 15% for horizontal modules).
3. Modular Row-by-Row Control:
Automatically shuts down redundant lamp rows based on flow sensor data (e.g., only 50% of the modules are active during low flow);
Reduces lamp start and stop cycles by 80%, extending lamp life to 14,000 hours (16.7% exceeding the contract requirement).
2.2 System Integration Innovation
Water level control | Electric bottom-opening weir gate (AISI304 stainless steel) with ±2 mm accuracy, adapting to water level fluctuations of 0.5–1.2 m |
Mechanical cleaning | Pneumatically driven scraper (air compressor system), combined with offline chemical cleaning vehicle, dirt removal rate ≥ 90% |
Intelligent central control | Siemens S7-300 PLC + 10-inch touch screen, real-time monitoring of UV intensity, dosage, energy consumption, support Ethernet remote interaction |
III. Wang Xiaoying Project Full-Process Implementation Plan
3.1 Project Overview and Design Challenges
· Treatment Capacity: 290,000 tons/day (peak flow rate 12,083 m³/h);
· Disinfection Target: Fecal coliform count ≤ 1,000 cells/liter (10⁷ cells/liter influent);
· Space Constraints: The width of the disinfection channel is limited (strictly specified in the bidding drawings), requiring compact and efficient equipment.
3.2 Customized Engineering Solution
(1) Module Configuration Optimization
· Lamp Selection: 540 low-pressure high-intensity lamps (GPHA1554T6L/4), single-tube UV-C output ≥110 W;
· Dosage Guarantee: Dual redundant design of scaling coefficient (0.8) and aging coefficient (0.5) to ensure end-of-life dose ≥25 mJ/cm²;
· Channel Layout: 2 open channels (L×W×H=25 m×1.8 m×1.5 m), guide plate + rectifier grid to optimize flow pattern.
(2) CFD fluid simulation verification
Computational fluid dynamics (CFD) was used to simulate the flow field and light field in the disinfection channel:
· Flow velocity uniformity: Adjusting the guide plate angle to 30°, the flow velocity standard deviation decreased from 0.35 m/s to 0.12 m/s;
· Dose compliance verification: The RED value at the most unfavorable point (channel bottom corner) reached 28 mJ/cm², exceeding the design standard by 12%.
(3) Anti-fluctuation operation strategy
· Intelligent frequency conversion: The ballast (Onyx-DIM-AHO-1320UV) output is 50–100% stepless adjustment to respond to flow changes;
· Water level linkage: The liquid level meter is linked to the start and stop of the UV module, and the power is automatically cut off at low water level to avoid idle light loss.
IV. Operational Efficiency and Economic Analysis
4.1 Disinfection Efficiency Data
Index | Design value
| Measured value
| Advantages |
Effluent fecal coliform bacteria | ≤1,000 pieces/L | 200–800pieces/L | Stable compliance with standards, no resistant bacteria escape |
Effective dose (end of life) | ≥25 mJ/cm² | 28–32 mJ/cm² | Redundant design ensures long-term reliability |
Energy consumption per ton of water | ≤0.012 kWh/m³ | 0.008 kWh/m³ | Intelligent control saves 33% energy |
4.2 Comparison of Life Cycle Costs
Cost Items | Traditional chlorine disinfection | WTV UV disinfection | Savings
|
Cost of chemicals/energy consumption per ton of water | ￥0.18 | ￥0.11 | 39% |
Equipment maintenance fee (year) | ￥1.2 million | ￥650,000 | 46% |
Secondary pollution control costs | ￥500,000 (excluding residual chlorine) | ￥0 | 100% |
4.3 Environmental and Social Benefits
· Ecological Safety: No toxic byproducts, recycled water can be used for urban greening and industrial cooling;
· Carbon Emission Reduction: Annual electricity savings of 4.2 million kWh, equivalent to a reduction of 3,348 tons of CO₂;
· Industry Demonstration: Providing technical templates for over 50 large-scale wastewater treatment plants in China (such as Zhuyuan in Shanghai and southern Shenyang).
V. Industry Promotion Value of Vertical Module Technology
5.1 Adaptability for Large-Scale Wastewater Treatment Plant Upgrading
· Efficient Space Utilization: The modules are highly integrated, occupying 30% less space than traditional systems;
· Flexible Scalability: Supports phased channel upgrades, avoiding plant-wide shutdowns (Wang Xiaoying's project involved two phases of construction);
· Intelligent IoT: Data is connected to the smart water platform, enabling unmanned disinfection workshops.
5.2 Technology Evolution
1. AI Dose Prediction: Combining water quality sensing with machine learning to dynamically optimize lamp output;
2. Low-Carbon Material Application: The quartz sleeve has a 95% recycling rate, reducing the carbon footprint over the entire lifecycle.
VI. Conclusion: Reshaping a New Paradigm for Municipal Wastewater Disinfection
The success of the Wang Xiaoying project demonstrates the irreplaceable role of vertical modular UV disinfection technology in large-volume municipal wastewater treatment applications:
· Technical: The plum blossom-shaped vertical arrangement combined with intelligent row-by-row control resolves the contradiction between efficiency and energy consumption;
· Economic: Cost savings exceeding 26 million RMB over a 10-year operating cycle, with a payback period of less than 5 years;
· Strategic: Providing green technology support for upgrading wastewater treatment plants in line with my country's "dual carbon" goals.
ONYX's technology system, centered on "light field reconstruction, intelligent response, and low-carbon operation," is driving municipal wastewater disinfection from chemical reliance to a new era of physical precision.
Municipal Wastewater
Municipal water supply
Recycled Water Reuse
Township water supply and drainage
Industrial Park
New pollutant control
Water ecological restoration project
