Sand filtration

[guru]

I came across an interesting article: ftp://ftp.fao.org/docrep/fao/010/y5118e/y5118e09c.pdf

It has got some info on how tribal people process spirulina for food use. Its a very simple process where they use sand for removing excess water (sand filtration and solar drying)and dry them as well. I think this can be applied to algae for fuel also?

[cacofonix]

Guru,

This is very interesting...

I just did some back-of-envelope calculations. At 4-5 cm thick algae cake, it comes to over 400 T of algae that can be recovered every time from a hectare of sand filter. This is enormously high, and just imagine how much more it will be per day, since from the document you had linked to, it appears that they can complete a drying process every 20 minutes.

I need to recheck my numbers, as they appear to be unbelievably high, bit if the data I have calculated is correct, I wonder why anyone is not trying this method on a large scale? Why bother with far more expensive techniques such as centrifuges, flocculation etc?

Thanks once again for the link, very interesting!

[guru]

I wonder how come they separate the cakes without sand particles... as they do this process for Human consumption?