Very interesting, Tango. I'll have to wife talk to some of the pottery people at the college where she works, and see if this is a feasable thing to accomplish locally. It seems that the clay mixture and the silver biocide coating are the keys to getting this to work.
Just though the mixing coffee or rice hulls in the clay and burning'em out technique was good "mcgyvering knowledge" to tuck away...
The wife found this site: http://www.pottersforpeace.org/ It goes into some more detail, but still no exact formula for the colloidial silver stain or the exact composition of the clay/sawdust/etc mixture. I like the 5 gallon bucket idea, that would make things really easy.
You could simply treat the "filtered" water with colloidal silver after the filtration to kill organic nasties. I'll talk to my step dad about the idea of mixing silver into the clay.
Still checking, Tracy. Art majors are... fickle. Especially when they don't understand why you would want an ugly flower pot to put dirty water in and clean water out. Oh, and it has to fit in a boring 5 gallon bucket, yawn. Why do you need that if you can just use the sink to get water?