Larval Settlement Suppression via 409-412 nm Light Irradiation
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Solution Overview
Problem
Larvae of sessile invertebrates, such as mussels and oysters, often settle in power plant intake and outfall structures, causing clogging issues due to their swimming and crawling behavior, which existing methods like chlorine-based substances, photocatalysts, and laser beams fail to effectively prevent.
Innovation Solution
Irradiating larvae with light in the spectrum of 409 to 412 nm, along with a part of 400 to 440 nm, using an LED beam with a peak intensity of 59.4 μWcm−2nm−1 or higher, to induce a shell-closure response and prevent swimming or crawling, effectively stopping them from settling on substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorine-based substances are injected into coolant to suppress settlement of marine invertebrates, then settlement suppression is achieved, but harmful effects on marine environment and potential clogging still occur
Solution Approach 1:
The patent replaces chemical methods (chlorine-based substances) with a physical method (light irradiation at 409-412 nm) to stop larvae from swimming or crawling. This substitution eliminates the harmful chemical effects on marine environments while maintaining the effectiveness of preventing settlement and clogging in power plant cooling systems.
2Reliability
If photocatalysts or laser beams are used to stop larvae, then settlement prevention is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs LED lights emitting at 409-412 nm, which are inexpensive, commercially available components with long operational life. This approach replaces complex photocatalyst systems or high-power laser beam apparatus, significantly reducing device complexity and cost while achieving the same larvae settlement prevention effect.
3Reliability
If existing methods are used to prevent larva settlement, then some protection is achieved, but larvae continue to swim and crawl causing clogging
Solution Approach 1:
The patent changes the wavelength parameter of light irradiation to specifically 409-412 nm, which has been determined to be the most effective range for stopping larvae from swimming or crawling. This precise parameter adjustment ensures complete immobilization of larvae, preventing both settlement and clogging issues that persist with other methods.
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 method effectively prevents larvae from swimming or crawling by causing them to retract their velum and foot into the shell, reducing settlement and potential clogging in power plant systems, with higher irradiance leading to quicker and more consistent shell closure responses.
Implementation Method 1
larvae in the settlement stage tend to stop from swimming or crawling in water when they are irradiated with light including the spectrum of 409 to 412 nm
Data Source
AI summary
The present invention provides a method of stopping larvae of sessile invertebrates in the settlement stage from swimming or crawling in water, by irradiating light comprising the spectrum of 409 to 412 nm and a part of 400 to 440 nm, to the larvae in the settlement stage.