How can we ensure comprehensive sterilization when using ultraviolet disinfection in the disinfection process of sewage treatment equipment?
Release Time : 2026-03-23
In the disinfection process of sewage treatment equipment, ultraviolet (UV) disinfection technology, with its advantages of high efficiency, environmental friendliness, and no secondary pollution, has become a key means of ensuring effluent safety. To ensure the comprehensive sterilization effect of UV disinfection, a comprehensive approach is needed, encompassing sewage treatment equipment design, water pretreatment, UV dosage control, system maintenance, and intelligent monitoring, to achieve a holistic and sustainable disinfection effect.
The core principle of UV disinfection is to use specific wavelengths of ultraviolet light (mainly the UVC band) to destroy the DNA or RNA structure of microorganisms, rendering them unable to reproduce and thus achieving inactivation. However, UV penetration is relatively weak and easily affected by water quality conditions. If suspended solids, turbidity, or color in the water is too high, UV light will be partially absorbed or scattered, resulting in insufficient radiation dose reaching the microorganisms and affecting the sterilization effect. Therefore, water pretreatment is the primary step in ensuring the comprehensiveness of UV disinfection. Reducing the concentration of suspended solids in wastewater through processes such as sedimentation and filtration (typically requiring SS below 30 mg/L) and controlling turbidity (generally below 5 NTU) can significantly improve the penetration rate of UV light and ensure the disinfection effect.
Precise control of ultraviolet (UV) dosage is crucial for comprehensive sterilization. The UV dosage is determined by the product of radiation intensity and irradiation time, and must be comprehensively determined based on the target microorganisms, water quality characteristics, and discharge standards. For example, for wastewater after conventional secondary biological treatment, the UV dosage typically needs to meet certain standards; while for reclaimed water or scenarios with higher hygiene requirements, the dosage needs to be further increased. In practical design, computational fluid dynamics (CFD) simulations are needed to optimize the reactor structure, ensuring uniform water flow distribution, avoiding short-circuiting or dead zones, and ensuring all microorganisms are fully exposed to UV radiation. Furthermore, using medium-pressure UV lamps or multi-lamp combinations can expand the UV coverage area and improve dosage uniformity.
Equipment maintenance and cleaning are important aspects of ensuring the long-term effectiveness of UV disinfection. During operation, impurities in the wastewater gradually adhere to the surface of the UV lamp tubes or quartz sleeves, forming a dirt layer that hinders UV transmission. Therefore, the lamp tubes need to be cleaned regularly, either manually or automatically (e.g., mechanical brushing, chemical cleaning, or ultrasonic cleaning), to remove surface deposits and restore light transmittance. Simultaneously, UV intensity needs to be monitored regularly. When the lamp radiation intensity decays to a certain percentage of its initial value, the lamp should be replaced promptly to ensure stable disinfection effects. Furthermore, when sewage treatment equipment is shut down, residual wastewater in the pipes must be drained to prevent microbial growth or biofilm formation in low-temperature environments, which could affect subsequent disinfection efficiency.
The application of an intelligent monitoring system can significantly improve the accuracy and reliability of UV disinfection. By installing UV intensity sensors, flow meters, and water quality monitoring instruments within the reactor, UV dosage, water flow velocity, and water quality parameters (such as turbidity and UV transmittance) can be monitored in real time. Based on feedback data, the system automatically adjusts lamp power or operating time to ensure that disinfection effects consistently meet standard requirements. For example, when the influent turbidity suddenly increases, the system can automatically increase the UV dosage or extend the irradiation time; when lamp aging causes a decrease in radiation intensity, the system will trigger an alarm and prompt lamp replacement. In addition, the intelligent monitoring system can record operational data, providing a basis for optimizing sewage treatment equipment and troubleshooting.
The comprehensive sterilization effect of UV disinfection technology also requires synergy with other treatment processes. For example, installing ozone oxidation or activated carbon adsorption units before UV disinfection can remove recalcitrant organic matter and some microorganisms from wastewater, reducing the load on subsequent UV disinfection. Adding chlorine or chlorine dioxide disinfection after UV disinfection provides continuous sterilization and prevents the regrowth of microorganisms within the pipes. Furthermore, for special scenarios (such as hospital wastewater or high-risk industrial wastewater), UV disinfection can be combined with photocatalysis. UV light activates photocatalysts (such as titanium dioxide) to generate hydroxyl radicals, enhancing the degradation of microorganisms and organic pollutants and further improving the comprehensiveness of disinfection.
The application of UV disinfection in wastewater treatment equipment requires comprehensive measures, including water pretreatment, precise dosage control, equipment maintenance and cleaning, intelligent monitoring, and multi-process synergy, to achieve comprehensive sterilization and long-term stability. With continuous technological advancements, UV disinfection technology will play an even greater role in ensuring effluent safety and promoting the green development of the wastewater treatment industry.