Fine bubbles are very useful in a post-harvest seaweed washing and freshness system as they can combine two functions in the same water:
1. Provide dissolved oxygen (DO) to keep harvested seaweed metabolically alive.
2. Create gentle water movement and bubble–surface contact that helps detach sand, silt, mucus, epiphytes and other contaminants.
Post-harvest seaweed is still biologically active and continues to respire.
As no more sunshine is available to such seaweed, water having high oxygenated level is necessary to meet the respiration demand by seaweed of very high biomass level in small water tanks.
Inside the washing tank:
Pump → fine-bubble nozzle → bottom/side injection → rising fine bubbles → seaweed → surface overflow/filtration → recirculation
Fine bubbles perform three functions simultaneously:
| Function | Effect on seaweed |
|---|---|
| Oxygen transfer | Maintains adequate dissolved oxygen around the seaweed |
| Gentle agitation | Loosens sand, mud, debris and attached organisms |
| Water circulation | Prevents stagnant, low-O₂ zones inside a pile of seaweed |
| Bubble/surface interaction | Helps lift some light organic particles and mucus toward the surface |
| Mixing | Makes washing more uniform than simply soaking |