UVA LED Water Sterilization Suppressing Photoreactivation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing UV-based water treatment methods are ineffective in preventing bacterial reactivation due to photoreactivation, where microbes rendered inactive by UV light can recover when exposed to sunlight, reducing the long-term effectiveness of disinfection.
Innovation Solution
An outdoor water treatment apparatus using UV LEDs that emit UVA ultraviolet light with a primary emission peak of 320nm to 400nm to kill bacteria and prevent reactivation, combined with optional UVC light sources, ensuring continuous disinfection even in sunlight exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional UV light treatment is used to disinfect water, then bacteria are killed initially, but bacteria recover and multiply due to photoreactivation when exposed to sunlight
Solution Approach 1:
The patent applies preliminary anti-action by using UVA light (320-400nm) before sunlight exposure to prevent photoreactivation. The UVA light damages the photolyase enzymes in bacteria, so when sunlight subsequently activates these enzymes to repair UV damage, the bacteria cannot recover. This preemptive damage to the repair mechanism ensures long-term disinfection effectiveness.
Solution Approach 2:
The patent changes the wavelength parameter of UV light from conventional UVC (200-280nm) to UVA (320-400nm). This parameter change is crucial because UVA light both kills bacteria and prevents photoreactivation by damaging photolyase enzymes, whereas conventional UVC light only kills bacteria initially but allows recovery when exposed to sunlight. The wavelength parameter change fundamentally alters the disinfection mechanism and duration.
2Productivity
If UVC light is used for disinfection, then bacteria are killed effectively, but the treatment is ineffective in outdoor conditions due to photoreactivation
Solution Approach 1:
The patent changes the UV wavelength parameter from UVC (200-280nm) to UVA (320-400nm) to enable outdoor water treatment. This parameter change allows the disinfection system to function effectively in outdoor conditions by preventing photoreactivation, while still maintaining bacteria killing efficiency. The UVA wavelength range is specifically chosen to achieve both objectives simultaneously.
Solution Approach 2:
The patent applies preliminary action by using UVA light treatment before potential sunlight exposure. The UVA light pre-damages the photolyase enzymes in bacteria, so when sunlight later arrives, the bacteria cannot perform photoreactivation. This preliminary enzymatic damage ensures the disinfection remains effective in outdoor environments.
3Reliability
If UV LEDs with emission peak of 320nm to 400nm are used, then photoreactivation is suppressed and bacteria cannot recover, but the light source must be precisely controlled to avoid eye damage
Solution Approach 1:
The patent changes the UV emission wavelength parameter to 320-400nm (UVA range) which suppresses photoreactivation while being safer for human eyes compared to shorter wavelength UV. The specific wavelength parameter range is carefully selected to achieve the dual benefit of preventing bacterial recovery and reducing harmful effects on human tissue.
Solution Approach 2:
The patent applies local quality by targeting specific wavelength ranges (320-400nm) that have different biological effects. This wavelength selection creates a localized quality in the light output that is effective against bacterial photoreactivation while being less harmful to human eyes, thus differentiating the light's effect on bacteria versus human tissue.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively maintains a disinfected state by suppressing photoreactivation, allowing for 24-hour continuous operation without eye damage and ensuring treated water does not harm the environment or human health, effectively reducing bacterial populations in outdoor water sources.
Implementation Method 1
The UV LEDs 1 include UV light emitting diodes (LEDs) that emit UVA ultraviolet light
Implementation Method 2
When irradiated with UV, nucleic acid absorbs the UV light and adjacent pyrimidine bases (primarily thymine) bond covalently to form a pyrimidine dimmer
Implementation Method 3
Photoreactivation is a result of activation, by light with a wavelength close to 400nm, of genetic repair enzymes (photolyases) that repair pyrimidine dimmer lesions
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
[Problem to be solved] To kill bacteria with ultraviolet light that can effectively kill bacteria with ultraviolet light and to suppress bacteria increase due to photoreactivation after disinfection. [Means to solve the problem] Bacteria in water 9 exposed outdoors are effectively killed with ultraviolet (UV) light by suppressing post-treatment increase in the bacteria population due to photoreactivation. The apparatus shines UV light on the water 9 to kill bacteria and has UV light emitting diodes (LEDs) 1 that emit UVA light with a primary emission peak of 320nm-400nm. The antibacterial action of the UVA light emitted by the UV LEDs 1 prevents proliferation of bacteria in the disinfected water 9 due to photoreactivation.