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 CFPPA-HYERES Spirulina Training Program

"spirulina WORLD program"
CFPPA , 32 chemin St Lazare 83400 Hyéres - France

  10 - Harvesting -
Harvesting by filtration
Harvesting is done by passing the culture over a fine filter screen - polyester cloth with 30-micron diameter holes. The filter screen is inclined slightly so that the accumulating Spirulina filter cake moves gradually toward the lower edge of the filter screen, where it is rinsed, collected, and then sent to a dewatering station where water is extracted by vacuum, by pressing, or by gravity through a vibrating screen. The filter cake, or paste, now can be cut with a knife and it will retain its shape; but it still contains 70 to 80% water .
If the Spirulina is left in this state, because it is such a good food it will be invaded by bacteria and fermented into an unapproachable stinking mass within a few hours - depending upon the temperature. This is why the Aztecs and the Kanembous poured the Spirulina concentrate into shallow basins they hollowed out of the sand. The sand allowed the water to filter down through to the ground and the hot sunshine dried it in 4 or 5 hours, which stopped any fermenting action by bacteria.
However, exposure to direct sunlight bleaches and destroys the green pigment, chlorophyll, and degrades the B-vitamin content of Spirulina. So, artisanal and small-scale Spirulina farms use solar dryers which avoid direct contact between the algae and the sunlight - a black-painted metal box which allows air to pass over and under the algae cake.
Spirulina drying on the sun
drying spirulina on the sand
Extruding Spirulina
Extruding Spirulina Cake
This is done by extruding fine (about 2-mm diameter) "noodles" of the algae cake onto plastic screens (about l-mm diameter holes) ...screens which are stretched tightly over wood or metallic frames that are nested inside the dryer box ...the dryer box having equal sized inlet and outlet holes to allow an unobstructed passage of air .
One can improve efficiency by heating the air under glass or plastic before it enters the dryer box. This creates a draft which pulls a greater quantity of air through the box. Bear in mind that it is not the heat that dries the algae but the capacity of a lot of air to absorb moisture as it passes across the algae cake.
When producing several kilograms of dried algae per day it is much more convenient to create a black plastic walk-in sized tunnel equipped with a large diameter evacuation fan. Many "noodle" trays can be stacked one over the other in wood or metal racks. The advantages of extruding "noodles" onto the drying screens instead of just spreading a thin layer of algae cake on top are, first, that air circulates around all sides of a "noodle" and hence the cake dries more quickly. Second, it is much easier to remove "noodles" from a screen than to scrape and chip away at a smooth-surfaced dry product. Third, spreading a film of algae cake onto a screen pushes it into the mesh of the screen where, when it dries, it is gripped tightly by the screen.
solar dryier
Spirulina solar drier system
- Introduction ] CD-ROM Spirulina for Reducing Malnutrition - Historic of the World ]
- SPIRULINA Composition  ]   [  - Texcoco Lake Story  ]
 [ -  
WHERE SPIRULINA is found ] [  - Basins  ]   [  - Photosynthesis ]  
- SPIRULINA Production  ]  [  - Laboratory ]  [  - Harvesting ]
- Mix-drying SPIRULINA ]   [  - Starting ]  [ Problems and Solutions  ] 
[  -
- Why should we grow SPIRULINA ? : for nutrition and health ]
- Public Information-paper on SPIRULINAuseful links ]


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